Electric Power Research Institute
TEXTILE INDUSTRY: PROFILE AND DSM OPTIONS
Prepared by RESOURCE DYNAMICS CORPORATION
and BATrELLE-COLUMBUS DIVISION
R E P O R T SUBJECTS TOPICS
AUDIENCE
S U M M A R Y
Demand-side planning / Industrial / Market assessment Demand-side management Demand-side planning Electrotechnology
Industrial technology alternatives Marketing Load management
Customer service representatives / Demand-side, R&D, and corporate planners / Marketing managers
Textile Industry: Profile and DSM Options Demand-side management approaches and emerging electrotechnologies promise to increase the efficiency and productivity of the textile industry. This guidebook provides utilities with a comprehensive overview of the textile industry's challenges, manufacturing processes, technologies, and energy-use patterns, as well as opportunities for electrotechnologies and demand-side management options.
BACKGROUND
OBJECTIVES
Throughout the utility industry, demand-side management (DSM) is gaining greater acceptance as a resource that promotes value for utilities as well as their customers. The great diversity in industrial business situations and energy-use patterns, however, often makes it difficult to understand how to apply DSM in the industrial sector. By better understanding their customers' needs and the technology options available, utilities can develop programs that are more successful in promoting DSM and electrotechnology applications. To identify opportunities for improving energy efficiency, enhancing productivity, and promoting load management objectives.
-To help utilities develop and implement DSM programs. APPROACH
RESULTS
EPRl CU-6789s
On the basis of literature surveys and interviews with experts in the textile and utility industries, investigators created this guidebook to describe the textile industry and advise on the selection of appropriate DSM and electrotechnology approaches. As background for their research, they relied on the DSM framework developed under EPRl's DSM project (report EAIEM-3597). This guidebook presents a detailed profile of the textile industry, providing information about the markets, processes, technologies, and energy-usage patterns of the major types of customers in this industry. Following the framework of the DSM project, it presents the DSM technologies and market implementation methods appropriate for achieving the various load-shape objectives within the textile industry. It describes a step-by-step approach for the development of a DSM plan that can help not only the utility but Electric Power Research Institute
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also textile customers, through lower energy costs, greater productivity, and improved product quality. EPRl PERSPECTIVE
This textile industry guidebook is part of a broad framework of tools and data designed to assist utilities in working with the industrial sector. These products help utilities better understand and meet the needs of their industrial customers. They also suggest how utilities can help achieve their load-shape objectives in the industrial sector. Among EPRl's other industry-related products is IMlS (Industrial Market Information System software), available through the Electric Power Software Center, to help utilities identify markets for various electrotechnologies. In addition, lndustrial Load Shaping: An lndustrial Application of DSM (report CU-6726) describes a methodology and real-world applications of DSM in the industrial sector. Tech Applications and Tech Commentaries, available through EPRl's Centers for Materials Production and Materials Fabrication, further explain how industries can benefit from electrotechnologies. And lndustry Briefs, currently under development and available in mid-1990, will provide insight into industrial processes, technologies, and energy-use patterns at the three- and four-digit SIC level. When used together, these documents will aid in development of DSM programs that will benefit both utilities and their industrial customers. ~
PROJECT
RP2885-1 EPRl Project Manager: Paul C. Meagher Customer Systems Division Contractors: Resource Dynamics Corporation; Battelle-Columbus Division
For further information on EPRl research programs, call EPRl Technical Information Specialists (415) 855-2411.
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Textile Industry: Profile and DSM Options
CU-6789 Research Project 2885-1 Final Report, July 1990
Prepared by RESOURCE DYNAMICS CORPORATION 8605 Westwood Center Drive Vienna, Virginia 22180 BATTELLE-COLUMBUS DIVISION 505 King Avenue Columbus, Ohio 43201
Prepared for Electric Power Research Institute 3412 Hillview Avenue Palo Alto, California 94304 EPRl Project Manager P C. Meagher Demand-Side Planning Program Customer Systems Division
ORDERING INFORMATION Requests for copies of this report should be directed to Research Reports Center . (RRC), Box 50490, Palo Alto, CA 94303, (415) 965-4081. There is no charge for reports requested by EPRl member utilities and affiliates, U.S. utility associations, U.S. government agencies (federal, state, and local), media, and foreign organizations with which EPRl has an information exchange agreement. On request, RRC will send a catalog of EPRl reports.
Clecinc Power
Research Institute and EPRl are registewd service m a r k of Electric Power Research Institute, Inc
Copyright 0 1990 Electric Power Research Institute, Inc All rights reserved
NOTICE This report was prepared by the organmtion(s) named below as an account Of w r k sponsored by the Electr~c Power Research Institute. Inc (EPRI) Neither EPRI, members of EPRI. the arganiralion(s) named below, nor any pefson acting on behalf Of any of them, (a) makes any warranty, enpress or impled. with respect to the use of any information. apparatus. method. or process disclosed in this repon 01 that such use may not infringe privately owned rights: or (b) assumes any liabilities with respect to the use of, or lor damages resulting from the use of. any information. apparatus. method, or process disclosed in this report. Prepared by Resource Dynamics Corporation Vienna. Virginia and Banelie-Columbus Division Columbus, Ohio
ABSTRACT
The T e x t i l e I n d u s t r y Guidebook provides e l e c t r i c u t i l i t y planning, marketing, and customer s e r v i c e s t a f f w i t h a p r a c t i c a l t o o l t o b e t t e r understand t h e t e x t i l e i n d u s t r y and t h e challenges i t faces: i t s manufacturing processes, technologies, and energy use; and i t s o p p o r t u n i t i e s f o r demand-side management (DSM).
The Guidebook
concludes w i t h guidance and summary data f o r developing and e v a l u a t i n g DSM plans t o r e a l i z e such o p p o r t u n i t i e s .
iii
ACKNOWLEDGMENTS
The Resource Dynamics Corporation and Battelle-Columbus D i v i s i o n wish t o thank t h e numerous t e x t i l e companies, associations, equipment s u p p l i e r s , government agencies and u t i l i t i e s t h a t a s s i s t e d i n p r o v i d i n g information used i n t h i s study.
Of
p a r t i c u l a r n o t e were t h e c o n t r i b u t i o n s o f D r . Gary N. Mock o f North Carolina State U n i v e r s i t y and N. James Covington. Paul Meagher o f t h e Demand-Side Planning Program o f t h e Customer Systems D i v i s i o n (CSD) coordinated t h i s p r o j e c t . I. L e s l i e Harry and K. R. Amarnath o f CSD's I n d u s t r i a l Program provided valuable review and i n p u t , as w e l l as t h e T e x t i l e I n d u s t r y Scoping Study, an important precursor t o t h i s Guidebook.
Resource Dynamics Corporation B a t t e l le-Columbus D i v i s i o n February, 1990
V
CONTENTS Sect i o n
5-1
EXECUTIVE SUMMARY Purpose o f t h e Guidebook
1
The T e x t i l e I n d u s t r y
5-1 5-1
Business and Product Trends
5-5
Manufacturing Processes and Energy Use G e t t i n g S t a r t e d : C h a r a c t e r i z i n g Potent ia1 DSM O p p o r t u n i t i e s
5-8
1-1
OVERVIEW OF THE TEXTILE INDUSTRY Purpose o f t h e Guidebook The T e x t i l e I n d u s t r y Business and Product Trends
1-1 1-2 1-3
Opportunities f o r the E l e c t r i c U t i l i t y Industry
1-5 1-6
How t o Use t h i s Guidebook
1-7
Organization o f t h i s Guidebook
1-10
E l e c t r i c i t y ' s Role i n Improving Competitiveness
2
MEETING TEXTILE-CUSTOMER NEEDS THROUGH ELECTRICITY T e x t i l e E l e c t r i c i t y Use by I n d u s t r y Segment and Process Importance o f E l e c t r i c i t y Competing Technologies and Energy Sources Technology A c q u i s i t i o n and Decision Making
3
5-13
2-1
2-3 2-3 2-5 2-7
A b i l i t y t o Modify E l e c t r i c i t y Use
2-9
DSM Program O p p o r t u n i t i e s and Constraints
2-11
I d e n t i f i c a t i o n o f Appropriate DSM Programs E v a l u a t i o n and S e l e c t i o n o f DSM Programs
3-1 3-2 3- 2 3-3
Program Implementation
3-8
Program M o n i t o r i n g
3-8
DSM PLANNING AND IMPLEMENTATION S e t t i n g DSM Objectives
vii
CONTENTS (Continued) Section 4
DEVELOPING A DSM PLAN FOR THE TEXTILE INDUSTRY
APPENDIX A
4-1
Organizing f o r DSM
4-1
Step 1.
I d e n t i f y and Characterize T e x t i l e Customers
Step 2.
Analyze T e x t i l e E l e c t r i c Loads and End Uses
4-2 4-5
Step 3.
I d e n t i f y Applicable DSM Technologies and Process Changes
4-8
Step 4. Step 5.
I d e n t i f y Market Implementation Methods Evaluate and Select DSM Programs
4-9
Step 6.
Develop T e x t i l e - I n d u s t r y DSM Plan
4-18
OVERVIEW OF THE TEXTILE INDUSTRY
4-15
A- 1
The T e x t i l e I n d u s t r y
A-1
Suppliers t o the T e x t i l e Industry Major Markets and End Uses o f T e x t i l e M i l l Products
A-3
A-5
Regional Impacts o f T e x t i l e Production
A-8
Segmentation and S p e c i a l i z a t i o n I n d u s t r y Concentration
A-12 A-13
Competitive Forces and Imports
A-14
Cost-Based Competition
A-17 A-22 A-25
Impact o f Competitive Responses Business and Product Trends APPENDIX B MANUFACTURING PROCESSES AND ENERGY USE
8-1
U n i t Processes i n Dry Processing
B-8
U n i t Processes i n Wet Processing
8-12 8-14
T e x t i l e Production Costs T e x t i l e Manufacturing Processes and Technologies Energy Consumption in t h e T e x t i l e I n d u s t r y
6-17 B-19
E l e c t r i c i t y Use i n t h e T e x t i l e I n d u s t r y
8-25
Energy Consumption by S p e c i f i c Processes
B-30
viii
CONTENTS (Continued) Section APPENDIX C
TEXTILE INDUSTRY ELECTROTECHNOLOGY EQUIPMENT SUPPLIERS Adjustable Speed D r i v e Equipment Suppliers
c-1
Heat Exchangers and Heat Recovery Equipment Suppliers
c-3
I n f r a r e d Processing Equipment Suppliers I n d u s t r i a l Process Heat Pump Equipment Suppliers
c-4
C-6
Microwave Heating and Drying Equipment Suppliers Radiofrequency Heating and Drying Equipment Suppliers
C-8
U l t r a v i o l e t Curing Equipment Suppliers
c-9
APPENDIX D
DESCRIPTIONS OF SELECTED ELECTROTECHNOLOGIES FOR THE TEXTILE INDUSTRY
Radiofrequency Drying and Heating I n d u s t r i a l Process Heat Pumps Membrane Processes U l t r a v i o l e t Curing
c-7
D-1 0- 1
0-6 D-17
D-32 D-42
Microwave Processing
ix
ILLUSTRATIONS
Fiqure 5-1
The T e x t i l e Complex
5-2
5-2
Import Share o f T e x t i l e Markets
5-5
5-3
Basic Processes i n T e x t i l e Manufacturing
5-8
5-4
Importance o f E l e c t r i c i t y as an Energy Source:
2-1
Basic Processes i n T e x t i l e Manufacturing
2-1
2-2
Importance o f E l e c t r i c i t y as an Energy Source
2-4
4-1
Load P r o f i l e s f o r T e x t i l e M i l l s
4-6
4-2
U t i l i t y vs. Customer B e n e f i t s
4-18
4-3
I l l u s t r a t i v e DSM Plan:
4-20
A-1
The T e x t i l e Complex
A-2
A-2
End Uses o f T e x t i l e M i l l Products
A-7
A-3
1985 T e x t i l e I n d u s t r y Shipments by S t a t e
A-8
8-1
Basic Processes i n T e x t i l e Manufacturing
8-1
8-2
Yarn Formation: Process Flow, Energy Inputs, and Process Outputs
8-3
8-3
F a b r i c Formation: Process Flow, Energy Inputs, and Process Outputs
8-4
8-4
F l o o r Coverings: Process Flow, Energy Inputs, and Process Outputs
8-5
B-5
Nonwovens: Process Flow, Energy Inputs, and Process Outputs
8-6
8-6
T e x t i l e F i n i s h i n g : Process Flow, Energy I n p u t s , and Process Outputs
8-7
8-7
1985 T e x t i l e Energy Use
8-26
8-8
1985 T e x t i l e I n d u s t r y E l e c t r i c i t y End Uses
8-27
B-9
1985 Manufacturing E l e c t r i c i t y Use by Region
8-29
T e x t i l e Industry
S t r a t e g i c Conversation
xi
s- 10
ILLUSTRATIONS (Continued)
Figure B-10
1985 Process Heat Energy Sources
B-35
D- 1
Drying o f T e x t i l e Spools
D-3
D-2
Closed-Cycle Heat Pump System
D-6
D-3
Open-Cycle Heat Pump
0-7
0-4
Open-Cycle I n d u s t r i a l Heat Pump
D-10
D-5
P e r m s e l e c t i v i t y o f RO and UF Membranes
D-19
D-6
Generalized Schematic o f T e x t i l e Treatment Processes
D-20
D-7
Membrane-Based Hybrid L i q u i d Separation Process
D-23
D-8
Spiral-Wound, Hollow-Fine-Fiber,
D-24
D-9
Cross Section of a Tubular RO Membrane and Schematic o f a Tubular RO Membrane Module
D-25
D-10
The Separation Spectrum
D-27
D-11
UV Curing Process
D-33
D-12
Types o f UV Sources
D-35
D-13
Commercial UV Processor U n i t s
D-36
D-14
Schematic Representation o f D i e l e c t r i c Hysteresis Heating
D-42
D-15
Comparison o f Microwaves and Conventional Drying
D-43
and Flat-Element Membrane
xii
TABLES
s-1
Textile Industry Summary: Industry Segments
5-14
S-2
Textile Industry Summary: Unit Processes or End Uses
5-17
s-3
Textile Industry Summary: DSM Technologies and Process Changes
5-20
s-4
Textile Industry Summary: DSM Market Implementation Methods
5-23
1-1
Textile Industry Summary: DSM Technologies and Process Changes
1-8
2-1
1985 Electricity Consumption by Specific Textile Processes
2- 4
2-2
1985 Non-Electric Energy Consumption by Specific Textile Processes
2-6
2-3
Selected Competing Energy Technologies
2- 8
2-4
1985 Textile Industry Electricity Costs and Intensity
2-12
4-1
Textile Industry Summary: lndustry Segments
4-4
4-2
Textile Industry Summary: Industry Energy Use
4- 7
4-3
Textile Industry Summary: Unit Processes or End Uses
4-10
4-4
Textile Industry Summary: DSM Technologies and Process Changes
4-12
4-5
Textile Industry Summary: DSM Market Implementation Methods
4-16
A-1
1985 Overview of the U.S. Textile Industry
A- 2
A-2
1985 Suppliers to the Textile Industry (Projected)
A- 3
A-3
1985 Manufacturing Sector Suppliers to the Textile Industry (Projected)
A- 4
A-4
1985 Manufacturing Sector Buyers of Textile Mill Products (Projected)
A- 6
A-5
1986 Regional Manufacturing Activity
A-10
A-6
1985 Textile Industry Manufacturing Activity
A-11
A-7
1986 Regional Impacts o f Textile Manufacturing
A-11
A-8
Ratios of Primary Product Specialization in Selected Textile Mills (Percent)
A-13
xiii
TABLES (Continued) Table A-9
Share o f T e x t i l e Shipments Accounted f o r by 20 Largest Companies (Percent)
A-14
A-10
Import Share o f T e x t i l e Markets (Percent)
A-15
A-11
Index o f Production f o r t h e T e x t i l e I n d u s t r y
A-16
A-12
Hourly Compensation Rates f o r T e x t i l e Production Workers
A-18
A-13
1983-1985 Permanent T e x t i l e Plant Closings i n t h e Southeast
A-20
A-14
New C a p i t a l Expenditures i n t h e T e x t i l e M i l l I n d u s t r y
A-21
A-15
Trends i n U.S. T e x t i l e I n d u s t r y P r o d u c t i v i t y ( P r o d u c t i v i t y 1977 = 100) Indexes
A-23
Comparative Rates o f Modernization i n Spinning and Weaving, 1985 (Percent)
A-24
A-17
Import Share o f T e x t i l e Machinery Market (Percent)
A-25
B-1
Dry and Wet Processing M i l l s Categories
B-8
8-2
T e x t i l e I n d u s t r y Average Costs Per D o l l a r o f Output by Cost Category and 3 - D i g i t S I C , 1985
8-14
8-3
T e x t i l e I n d u s t r y U n i t Labor Cost by Type, 1985
8-16
8-4
S t a t e - o f - t h e - A r t Text i1e Manufacturing Techno1o g i es--Dry Processing
B-18
B-5
S t a t e - o f - t h e - A r t T e x t i l e Manufacturing Technologies--Wet Processing
8-20
B-6
Advanced T e x t i l e Manufacturing Technologies
B-21
8-7
T o t a l Energy Consumption i n t h e T e x t i l e I n d u s t r y
B-22
B-8
1985 T e x t i l e I n d u s t r y Energy Costs and Energy I n t e n s i t y
B-22
B-9
Energy I n t e n s i t y i n t h e T e x t i l e I n d u s t r y
B-24
B-10
Energy P r o d u c t i v i t y Trends i n t h e T e x t i l e I n d u s t r y
8-24
B-11
E l e c t r i c i t y Consumption i n t h e T e x t i l e I n d u s t r y
B-26
B-12
1985 T e x t i l e I n d u s t r y E l e c t r i c i t y Use i n t h e Southeast
8-29
A-I6
-
xiv
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TABLES (Continued)
6-13 Energy Consumption in Dry Processing Mills
6-31
6-14 1985 Electricity Consumption by Specific Textile Operation
6-32
6-15 Energy Consumption in Wet Processing Mills
6-34
6-16 1985 Non-Electric Energy Consumption by Specific Textile Processes
6-36
D-1 D-2
Summary of Capital and Operating Costs for Closed-Cycle Heat Pumps Summary of Projected Capital Costs for New and Retrofit
D-13
MVR Systems
0-14
D-3
Comparison of Types of Membrane Permeators
D-28
D-4
UV Lamp Operating Characteristics
D-37
D-5
Comparative Microwave Drying Data
D-45
xv
EXECUTIVE SUMMARY
Electricity is more than just the largest energy source for textile manufacturers; it is a unique and invaluable resource for improving their troubled competitive position. Automation and emerging electric-based textile processing technologies promise to increase significantly the efficiency and productivity of the industry.
PURPOSE OF THE GUIDEBOOK
This Textile Industry Guidebook is designed to provide electric utility planning, marketing, and customer service staff with a practical tool t o : 0
Understand the textile industry and the challenges it faces
0
Understand energy use and the different processes and technologies found within the industry
0
Identify and characterize opportunities for improving energy efficiency, enhancing productivity, and promoting load management as sound approaches that will benefit both the customer and the utility
0
Help develop a demand-side management (DSM) plan to realize such opportunities.
The purpose of this Executive Summary is to acquaint the reader with the primary conclusions of the study and the technical information covered in the Guidebook.
THE TEXTILE INOUSTRY
The textile mill industry produces spun yarns, thread, woven and knit fabrics, and floor coverings such as rugs and carpets. It also produces nonwoven fabrics such as synthetic leathers, and miscellaneous textile products such as tire cord. The textile mill industry (or for the purposes of this study, simply the textile industry) is part of the "textile complex," a system of independent enterprises
s- 1
involving many segments outside of SIC 22 and tied together by complex business relationships. Figure S-1 highlights some of the relationships between these segments.
Natural Fiber Producers SICS 01,02
SICS 26,30, 31,37.39
Manmade Fiber Producers SIC 28
Furnishings SICS22.23,25
Figure S-1. The Textile Complex
In addition t o the textile industry (SIC 22), the textile complex consists of suppliers and markets for the textile industry. Suppliers include natural fiber producers in the agriculture industry (SICs 01 and 02), manmade fibers from the chemical industry (SIC 28), and textile machinery producers (SIC 3552). Markets include industrial fabrics (SICS 26, 30, 31, 37, and 39), home furnishings (SICs 22, 23, and 25), and apparel (SIC 23). The textile industry is its own biggest supplier, accounting for over 40 percent o f its inputs on a dollar basis. The chemical industry represents nearly 30 percent, and the agriculture sector accounts for another 8 percent. The three major end-use markets (apparel fabrics, home furnishings, and industry fabrics) each account for about one-third of all textile industry shipments.
Standard Industrial Classification (SIC 22) consists of the following 3-digit SIC sectors: SIC 221
-
SIC 222
- Manmade fiber weaving mills
Cotton weaving mills
- Wool weaving and finishing mills SIC 224 - Narrow fabric mills SIC 225 - Knitting mills SIC 226 - Textile finishing (except wool) SIC 227 - Floor covering mills SIC 228 - Yarn and thread mills SIC 229 - Miscellaneous textile mills. SIC 223
Reqional Impacts Approximately 80 percent of the total U.S. textile shipments originate from the Southeast region, while about 9 percent of shipments originate from the MidAtlantic states of New Jersey, New York, and Pennsylvania. Wool weaving and finishing mills (SIC 223) and narrow fabric mills (SIC 224) are concentrated in New England. This region accounts for 77 percent and 50 percent, respectively, of shipments in these two textile industry sectors. Due to the bulky nature of carpets (SIC 227), transportation costs are high, so floor covering mills are more widely dispersed in the U.S. than textile mills producing other textile products. Major carpet and rug mills are found in Georgia, California, Texas, North Carolina, and Tennessee.
Industry Concentration The textile industry consists of about 5,300 companies operating over 7,000 mills, ranging from highly integrated to small, independent plants. Many of these companies are small establishments performing single operations on a contract basis for other mills. The most common type of textile mill is the greige mill, in which spinning, knitting, and weaving operations are combined to produce greige goods--unfinished textile products.
5-3
Industry concentration varies from segment to segment. The highest concentration ratios are found in the cotton and manmade fiber industries (SICs 221 and 222) where the 50 largest firms accounted for approximately 97 and 90 percent of shipments in those sectors, respectively. The four largest firms accounted for 41 and 40 percent, respectively. The industry segments with the lowest concentration ratios are the knitting mills, textile finishing, and yarn and thread mills. Many of these mills are small, independently owned operations. With the recent number of mergers and acquisitions, these concentration ratios have increased considerably.
Production Costs Production costs in the textile industry, as in all other manufacturing sectors, consist of labor, raw material, energy, and other costs such as the cost of financial and insurance services, capital charges, and non-production supplies. Across all 3-digit textile SIC categories, raw material costs account for 40-70 percent of the average costs per dollar of output, averaging about 60 percent. Raw materials consist mostly of fiber or yarn staple. In finishing plants, chemical dyes are also a major raw material. The floor coverings industry is the textile sector whose raw materials cost captures the largest share (69 percent) o f a dollar of output. Labor costs average about 22 percent per dollar of output in the textile industry, but is as high as 29.7 percent in narrow fabric mills (where considerable detailed work is required to produce specialty items such as laces, beltings, ribbons, and bindings) and as low as 11.9 percent in floor covering mills (SIC 227). Fossil energy costs average about 1.3 percent of dollar output in SIC 22, but are higher in the textile finishing segment (SIC 226) due to the many fossil-fuelbased finishing and coating processes in that particular segment. Electricity cost per dollar of output in the textile industry as a whole averages about 2.3 percent. Electricity cost per dollar of output for the entire manufacturing sector (SICs 20-39) averages about 1.4 percent. Spinning and weaving mills are the most electricity intensive. In these mills (SICs 221, 222, and 228) electricity costs are 3 . 9 percent, 3.5 percent, and 3.8 percent of shipments, respectively.
s-4
BUSINESS AN0 PRODUCT TRENDS
In t h i s , t h e o l d e s t o f American manufacturing i n d u s t r i e s , many of the b a s i c manufacturing methods have n o t changed f o r decades o r longer.
The t e x t i l e
i n d u s t r y i s conservative and has been slow t o accept t e c h n o l o g i c a l change. Recently, however, cheaply produced f o r e i g n t e x t i l e products have gained a f o o t h o l d i n many domestic markets f o r c i n g w e l l - e s t a b l i s h e d manufacturers t o reexamine t h e i r competitiveness. R i s i n g l a b o r costs, a r a p i d l y - g r o w i n g array o f new chemical f i b e r s , and s o p h i s t i c a t e d t e x t i l e machinery must now be accommodated. Domestic and i n t e r n a t i o n a l competition and technology have combined t o f o r c e changes i n t e x t i l e manufacturing methods. R i s i n g imports o f t e x t i l e products now present a formidable economic t h r e a t d e s p i t e steady increases i n shipments, m i l l consumption o f f i b e r , and c a p a c i t y i n 1975, 14 percent o f a l l t e x t i l e goods s o l d i n t h i s c o u n t r y were imported; over 37 percent were imported i n 1986. I n the
utilization.
As shown i n Figure
S-2,
apparel f a b r i c s sector, imports captured over 50 percent o f t h e market i n 1986.
Apparel and Apparel Fabric
1970
1975
1980
1985
Year
F i g u r e S-2.
import Share o f T e x t i l e Markets
s-5
Most U.S.
i n d u s t r i e s have seen domestic market shares h e l d by imports increase due
t o a s t r o n g U.S. d o l l a r and a U.S. government p o s i t i o n f a v o r i n g f r e e trade. The t e x t i l e i n d u s t r y s i t u a t i o n has been a d d i t i o n a l l y a f f e c t e d by i t s h i g h l a b o r i n t e n s i t y (some 22 percent o f t o t a l output d o l l a r s ) and b y i t s dependence on f o r e i g n sources f o r t e x t i l e machinery. t e x t i l e machinery market.
Imports h o l d n e a r l y 60 percent o f t h e
This competition has forced t h e U.S.
t e x t i l e industry
t o seek ways t o improve performance by working towards f i v e important goals described i n t h e f o l l o w i n g paragraphs.
Improving Labor P r o d u c t i v i t y I n response t o increased f o r e i g n competition, t h e i n d u s t r y i s now attempting t o reduce t h e l a b o r content o f i t s products.
Between 1980 and 1985, t e x t i l e i n d u s t r y
employment d e c l i n e d 15 percent w h i l e shipments increased by 13 percent.
Wages
were a l s o cut, and constant d o l l a r value-added p e r f u l l t i m e e q u i v a l e n t employee i n t h e t e x t i l e i n d u s t r y grew f a s t e r than t h e average f o r a l l manufacturing.
As
t e x t i l e f i r m s c u t l a b o r costs, they increased c a p i t a l expenditures.
Improving Process E f f i c i e n c y T e x t i l e manufacturing i n v o l v e s mu1t i p l e , r e p e t i t i v e batch processing. This g e n e r a l l y r e q u i r e s considerable manual i n s p e c t i o n and i n t e r v e n t i o n because most technologies do n o t perform o p t i m a l l y o r lend themselves t o automation.
In the
p a s t , workers had t o be employed t o d e t e c t and r e p a i r breakages r e s u l t i n g from poor f i b e r q u a l i t y and t o avoid over- o r under-processing o f f a b r i c i n the Now, automation i s made p o s s i b l e by t h e increased use o f
f i n i s h i n g processes.
s y n t h e t i c s , more u n i f o r m q u a l i t y i n n a t u r a l f i b e r s , and advanced spinning and weaving technologies. S y n t h e t i c f i b e r s and improved n a t u r a l f i b e r s e l i m i n a t e t h e need f o r constant manual i n s p e c t i o n .
New technologies o f f e r f a s t e r f i b e r and f a b r i c processing
speeds and d i m i n i s h t h e r i s k o f expensive and t i m e consuming breakage r e p a i r s . Today, some t e x t i l e producers are experimenting w i t h f a s t e r - d r y i n g dyes and technologies designed t o e l i m i n a t e many intermediate process steps. T e x t i l e companies a r e a l s o moving toward computerized m o n i t o r i n g and c o n t r o l o f production processes and automated i n s p e c t i o n procedures t o ensure f i b e r , yarn, and f a b r i c q u a l i t y a t a l l p r o d u c t i o n stages.
S-6
Improving Product Quality The development of durable synthetic fibers and higher agricultural standards for natural fibers has yielded improvements in yarn strength, uniformity, and cleanliness. These advances in fiber quality lead to higher fabric quality, much o f which can be attributed to technology advances: improved fiber blends can be achieved by opening and picking equipment; new carding technology achieves better integration of fibers which results in fewer breakages; new loom designs process yarns at faster speeds; and state-of-the-art spinning machines produce firstquality fabric in a shorter period than conventional equipment.
Reducins Production Costs Although the U.S. textile industry's productivity level grew at a faster rate than the average for all manufacturing between 1976 and 1986 (5.2 percent annually compared to 2.8 percent), additional productivity improvements must be realized to maintain a presence in today's competitive market. Textile companies can lower production costs through a number of methods. Simplifying and accelerating production processes, for example, combining processes or using faster-drying dyes, would allow products to get to market more quickly. Today's rapid developments in fiber and fabric types require that newly-developed production processes be carefully researched to ensure applicability to all fibers and fabrics.
Meeting Environmental Requlations Electrotechnologies can be used, directly and indirectly, to meet federal, state, and local environmental restrictions placed on the textile industry. Direct environmental benefits from electrotechnologies appear to be promising. For example, membrane separation processes allow for recycling and recovery of useful thermal energy and chemicals used in textile drying and finishing, thus reducing the amount of hazardous chemicals disposed of by mills. Heat exchangers and heat recovery systems perform the same recycling task with similar advantages. Electricity used in lieu of conventional thermal processes eliminates or reduces point-source emissions. This indirect benefit can be substantial if large numbers of conventional thermal energy processes are replaced with electric-based technologies.
s-7
MANUFACTURING PROCESSES AND ENERGY USE
Typical t e x t i l e manufacturing f a c i l i t i e s are made up o f one o r more o f f i v e basic processes:
y a r n formation, t h r e e classes o f m a t e r i a l formation (woven/knitted
f a b r i c , f l o o r coverings, and nonwoven f a b r i c ) , and f i n i s h i n g .
These processes can
then be c a t e g o r i z e d i n t o two types o f processing, d r y and wet.
Basic T e x t i l e Processes F i g u r e 5-3 d e p i c t s t h e r e l a t i o n s h i p among these processes and processing categories. Each o f t h e f i v e b a s i c processes i s b r i e f l y described below.
Yarn Formation
+
Floor Covering Formation
I
;
Finishing/ Dyeing
I
I I I
b
Nonwoven Fabric Formation
I I
-1
Wet Processing (Finishing Mills)
Dry Processing (Greige Mills)
F i g u r e S-3. Yarn Formation.
Basic Processes i n T e x t i l e Manufacturing
Natural o r manmade f i b e r s o r blends are spun i n t o yarn through
various p i c k i n g , combing, and t w i s t i n g processes.
Yarn formation equipment such
as p i c k i n g , card, and combing machines gather f a b r i c s l o o s e l y i n t o a c o r d - l i k e form known as a s l i v e r . These s l i v e r s are passed through drawing frames t o increase alignment, then through a r o v i n g frame t o apply t w i s t .
S-8
Woven o r K n i t t e d Fabric Formation. Fabric formation i n v o l v e s t h e conversion o f yarn i n t o f a b r i c . A warping machine winds numerous separate strands o f yarn onto a beam.
A s l a s h i n g machine t r e a t s t h e yarn w i t h a s i z e , which i s a h o t s o l u t i o n o f s t a r c h , wax, o i l s , and water, t o coat and strengthen t h e yarn i n p r e p a r a t i o n f o r f u r t h e r processing. The yarn i s then woven o r k n i t t e d i n t o grey, o r unfinished, fabric.
F l o o r Covering Formation.
F l o o r coverings a r e produced e i t h e r by weaving o r by t u f t i n g , a process where yarn i s attached t o t h e carpet backing d i r e c t l y .
Nonwoven F a b r i c Formation.
I n nonwoven f a b r i c formation, yarns o r f i b e r s are
bound t o g e t h e r using adhesive chemicals o r heat. i n t h e i n d u s t r i a l and home f u r n i s h i n g sectors.
Nonwoven f a b r i c s a r e mainly used Web forming and bonding a r e
p e c u l i a r operations t o t h i s process.
Finishinq.
F i n i s h i n g processes vary w i t h t h e f a b r i c and product end-use; they i n c l u d e bleaching, mercerizing, dyeing, s a n f o r i z i n g , and heat s e t t i n g . These
operations a r e designed t o impart q u a l i t i e s such as c o l o r fastness, f e e l , and p r o t e c t i o n from shrinkage. These f i v e b a s i c processes i n v o l v e numerous and sometimes r e p e t i t i v e batch operations, which can be placed i n t o two broad categories--dry and wet, depending on whether o r n o t a l i q u i d i s involved. Dry processing o f t e n takes p l a c e i n greige m i l l s and includes a l l t h e t e x t i l e
processing operations t h a t take place through t h e stage where t h e yarn i s spun and t h e woven o r k n i t t e d grey f a b r i c i s formed (except slashing).
They i n c l u d e
opening, blending, carding, spinning, weaving, and k n i t t i n g .
Wet processing i n v o l v e s t h e m a j o r i t y o f processes t h a t dye o r f i n i s h t h e spun yarn o r woven/knit g r e i g e f a b r i c o r f l o o r covering.
Also included i n wet processing i s
slashing, which takes place p r i o r t o f a b r i c o r yarn dyeing and/or f i n i s h i n g but involves t h e a p p l i c a t i o n o f l i q u i d chemicals t o t h e yarn. Some m i l l s are now integrated.
s-9
T e x t i l e I n d u s t r y Energy Use As shown i n F i g u r e
5-4, e l e c t r i c i t y provides 31 percent o f t h e t o t a l energy used
i n t h e t e x t i l e i n d u s t r y and represents t h e i n d u s t r y ' s l a r g e s t source.
This compares w i t h t h e market share o f 19 percent h e l d by e l e c t r i c i t y f o r t h e e n t i r e manufacturing s e c t o r
(SICS 20-39).
Coal 19% Figure S-4. Importance o f E l e c t r i c i t y as an Energy Source: T e x t i l e I n d u s t r y Less than one percent o f e l e c t r i c i t y i s self-generated.
Cogeneration i s a
t e c h n i c a l l y v i a b l e o p t i o n f o r meeting some o f t h e i n d u s t r y ' s e l e c t r i c needs, due t o t h e l a r g e amounts o f process steam r e q u i r e d f o r d r y i n g and f i n i s h i n g , t h e existence o f waste products ( f i b e r s t h a t can be i n c i n e r a t e d ) , and t h e presence o f waste heat. However, many t e x t i l e p l a n t s are small establishments which may n o t be able t o a f f o r d t h e c a p i t a l investment r e q u i r e d t o cogenerate. The primary end uses o f e l e c t r i c i t y i n t h e t e x t i l e m i l l i n d u s t r y are motor d r i v e , l i g h t i n g , and process heat.
Motor d r i v e accounts f o r 83 percent o f t h e
e l e c t r i c i t y consumed i n t h e t e x t i l e m i l l i n d u s t r y .
L i g h t i n g , representing 15
percent, i s t h e n e x t l a r g e s t e l e c t r i c i t y consumer: process h e a t i n g a p p l i c a t i o n s represent o n l y about 2 percent. Motor d r i v e e l e c t r i c i t y use i s broken down i n t o m a t e r i a l s processing (45 p e r c e n t ) , m a t e r i a l s h a n d l i n g (35 percent), and pumps, fans, and compressors (about 20
s-10
percent). Materials-processing equipment performs the separating, combing, and other materials-processing steps that are carried out during spinning and weaving. Opening and card machinery, which use their steel fingers for plucking and combing, and spinning machinery, which twists and separates fibers, are materialsprocessing equipment. Materials-handling activities take place throughout textile manufacturing, starting from the rotating fiber-opening machinery to finishing, where fabric is printed or heat set using rollers and rolling frames. Materials handling also takes place during fabric formation where bales of fiber are moved through the mill. Pumps, fans, and compressors account for a large portion of the electricity used in HVAC systems. About 20 percent of the energy used in finishing mills is electricity, mostly to power small motors scattered through the mill. Pumps are used for fluid processing in dyeing to pump dyes, rinse water, and other liquids into and out of dye becks. Fans are also used in convection ovens used for drying and finishing and for blowers in opening and blending machines.
Textile Plant Enerqy Use and DSM Opportunities The importance of energy in a particular textile mill depends on the type o f processing that is done at the mill--wet or dry. In general, dry processes are electricity intensive while wet processes are fossil-energy intensive.
Dry Processing. The spinning, twisting, and weaving processes performed in these mills require considerable amounts of motive power. Except for slashing, all operations performed in the dry processing mill use electricity as the primary energy source. Steam used in the slashing operation is usually generated by boilers burning natural gas, coal, fuel oil, or other petroleum products. Electricity supplies about 80 percent of the total energy requirements in greige mill (dry mills). There are few opportunities for further electricity penetration in dry processing. Most of the increases will come from automation programs. A s more companies automate their plants and install computerized systems for process control, their reliance on uninterrupted electric power will increase, but only slightly. New technology developments that might increase electricity consumed by
s-11
drive motors include mechanical moisture-removal devices such as vacuum extractors and roller squeezers. Since a typical greige mill will have many motors running during a normal work day, there are numerous opportunities for conservation and load management in dry processing. For example, high-efficiency electric motors with adjustable speed drives can help this equipment run more efficiently, reducing overall electricity costs. HVAC systems are also very important in greige mills because they must work with the machinery to filter out the large amounts of debris, lint, and other material generated during production processes. Impaired air quality from the collection of cotton dust in the air, for example, may create a hazard to operators as well as a risk of potentially fouling the machinery. Opportunities for heat recovery exist for HVAC systems designed to capture waste heat from machinery and redirect it into the ventilation system, thus eliminating hot spots. More-efficient spinning, weaving, and knitting technologies will also provide opportunities for conservation.
Wet Processinq. Wet processing often requires large inputs of thermal energy, mainly to heat liquids and chemical dyes and to dry and finish textiles. Process heating is dominated by fossil fuels because they can heat evenly and inexpensively with readily available technologies. In textile processing, the quantity of heat, temperature, and method of application varies widely. Some methods (such as singeing) require direct applications of open flame, eliminating the possibility of electric process heat applications. Others require steam cans or calendars for the application of heat and pressure. In all cases the application and maintenance of a certain temperature is crucial to avoid over- or under-processing. The design and application flexibility of gas equipment allows ready application of heat in those processes where heat is required. The textile firm's ability to modify electricity use is more pronounced in wet processing applications than in dry. The majority of wet processes dye or finish spun yarn and woven or knit greige fabric. Also included in this category is a process called slashing, which takes place prior to fabric or yarn dyeing and/or finishing and involves the application of liquid chemicals to the yarn in order to improve weaving efficiency by strengthening the yarn. A variety of electric technologies now compete with conventional fossil-fuel-fired technologies for
5-12
s l a s h i n g , d r y i n g , dyeing, and c u r i n g . wet processing include:
Approaches f o r modifying e l e c t r i c i t y use i n
0
Increased a p p l i c a t i o n s o f process heating technologies --Radiofrequency --Infrared '--Ultraviolet curing
0
Increased a p p l i c a t i o n s o f o t h e r electrotechnologies --Membrane s e p a r a t i o d f i l t r a t i o n techniques - - I n d u s t r i a l process heat pumps/heat recovery systems --Thermal energy storage --Ultrasonics --Process automation.
Examples o f i n s t a l l a t i o n s i n c l u d e using i n d u s t r i a l process heat pumps and f i l t r a t i o n techniques t o recover waste chemicals and using e l e c t r i c heating technologies t o replace conventional dyeing and d r y i n g processes. opportunities also exist.
HVAC
F i n i s h i n g p l a n t s r e q u i r e l a r g e v e n t i l a t i n g systems f o r
t h e removal o f vapors, odors, fumes, and o t h e r contaminants.
GETTING STARTED: CHARACTERIZING POTENTIAL DSM OPPORTUNITIES As noted p r e v i o u s l y , e l e c t r i c u t i l i t i e s have many o p p o r t u n i t i e s t o h e l p t h e t e x t i l e i n d u s t r y f u r t h e r improve i t s competitive p o s i t i o n , w h i l e a t t h e same t i m e advancing u t i l i t y DSM o b j e c t i v e s .
These o p p o r t u n i t i e s range from o v e r a l l energy
conservation, t o l o a d management, t o t h e a p p l i c a t i o n o f s p e c i f i c e l e c t r o technologies. I n h e l p i n g t o understand t h e t e x t i l e i n d u s t r y and i t s p o t e n t i a l DSM o p p o r t u n i t i e s , a s e r i e s o f f o u r t a b l e s has been developed t o provide a f i r s t step i n c h a r a c t e r i z i n g t h e a v a i l a b l e DSM options and t o summarize t h e t e c h n i c a l i n f o r m a t i o n provided i n t h i s Guidebook. Please note t h a t t h e i n f o r m a t i o n represented i n each o f t h e t a b l e s r e f l e c t s t y p i c a l t e x t i l e plants.
Because s i g n i f i c a n t v a r i a t i o n s i n p l a n t design and
processing equipment e x i s t , caution i s required i n using t h i s information.
I n d u s t r y Seqments The f i r s t t a b l e (Table
S-1) summarizes t h e key c h a r a c t e r i s t i c s o f t h e n i n e t h r e e - d i g i t S I C segments o f t h e t e x t i l e i n d u s t r y . The information includes key
S-13
Table S-l TEXTILE INDUSTRY SUMMARY: INDUSTRY SEGMENTS
industry Segment (3-Digit Sic)
21.
Cotton Weaving
industry Trendrl
Industry Products
comments
Growthin home furnishin in durtrial.and medical mar?&; De O f Shipments rota1 Cost
Costs Per D o l l a r of Value A&ed
Total Cost ($Mils)
costs costs Per D o l l a r of Per vaLw Of Shipnents Value Added
Sector _______.__._..__..__--.------------...------------
-
Source:
Textile Industry
1,925
3.6%
9.3%
1,214
2.3%
5.9%
Process Industries
29,061
3.4%
10.0%
13,176
1.6%
4.6%
All Manufacturing
59,M7
2.6%
6.0%
31,595
1.1%
3.2%
U.S. Department o f Commerce, Bureau o f t h e Census, Annual Survey o f Manufactures, 1985.
8-22
i n d u s t r y t o t h e energy i n t e n s i t y i n t h e process and a l l manufacturing i n d u s t r i e s . The t a b l e shows t h a t a t 9.3 percent, 1985 energy costs p e r d o l l a r o f value added i s higher than t h e n a t i o n a l average o f 6 percent f o r a l l manufacturing b u t s l i g h t l y lower than t h e average f o r t h e process i n d u s t r i e s (10 percent). I n 1985, t h e c o s t o f e l e c t r i c i t y i n t h e t e x t i l e i n d u s t r y was 5.9 percent o f t h e i n d u s t r y ' s value added by manufacture, almost t w i c e t h e n a t i o n a l average o f t h e manufacturing sector.
E l e c t r i c i t y i n t e n s i t y i s higher than t h e average f o r t h e
process i n d u s t r i e s , perhaps a r e f l e c t i o n o f t h e t e x t i l e i n d u s t r y ' s lower r e l i a n c e on self-generated e l e c t r i c i t y t h a t i s so common t o process i n d u s t r i e s l i k e t h e petroleum, p u l p and paper, and chemical i n d u s t r i e s . The i n t e n s i t y a l s o demonstrates t h e importance o f e l e c t r i c i t y i n most t e x t i l e manufacturing processes. When examining t h e t r e n d i n t o t a l energy i n t e n s i t y ( f o r both purchased f u e l s and e l e c t r i c i t y ) between 1980 and 1985, i t can be seen from Table E-9 t h a t t o t a l energy i n t e n s i t y increased from 3.2 percent o f value o f shipments i n 1980 t o 3.6 percent i n 1985.
This change i n t o t a l energy i n t e n s i t y i s a t t r i b u t e d d i r e c t l y t o t h e almost 30
percent r i s e i n t h e e l e c t r i c i t y i n t e n s i t y compared w i t h t h e 7 percent d e c l i n e i n f o s s i l energy i n t e n s i t y .
During t h e same period, t h e c o s t o f e l e c t r i c i t y increased
a t a much f a s t e r r a t e (45 percent) than t h e c o s t o f purchased f u e l s (10 percent). This f u r t h e r e x p l a i n s t h e d e c i s i v e impact o f e l e c t r i c i t y i n t e n s i t y on t o t a l energy intensity
.
Despite t h e increase i n energy i n t e n s i t y , energy p r o d u c t i v i t y trends improved between 1975 and 1985 (as shown i n Table E-10). I n t h a t ten-year period, energy consumption per pound o f f i b e r went from 29,930 Etu t o 25,739 Etu. This t r e n d i n d i c a t e s t h a t widespread energy conservation e f f o r t s i n t h i s i n d u s t r y are achieving t h e i r goal o f processing more f i b e r w i t h reduced energy i n p u t .
6-23
Table 6-9 ENERGY INTENSITY I N THE TEXTILE INDUSTRY
1980
Cost Energy
Source:
(nil. 5)
Cost/$ ship. Cost/$ val.
(XI
Cost
.dded (74
(nil. f )
C o s t l t ship. Costlt v a l . (X) d e d (7.)
Electrical
840.2
1.8
4.4
1,214.2
2.3
5.9
Purchased Fuels
647.5
1.4
3.4
710.6
1.3
3.4
1.487.7
3.2
7.8
1.924.8
3.6
9.3
Total
-
Source
1985
U.S. Dept. o f Commerce, Bureau o f t h e Census, Annual Survey o f Manufactures, 1980 and 1985.
Table 6-10 ENERGY PRODUCTIVITY TRENDS I N TEXTILE INDUSTRY
Total Energy Used ( T r i l . Btu)
Mill Fiber Consumption ( M i l . lbs.)
Energy Use Per l b of Fiber (Bt4
Year ___-__---__-____________________________-----------------------
1975 1976 1977 1978 1979 1980 1982 1983 1984 1985
=e:
307.1 328.6 339.2 326.6 314.9 294.9 262.4 288.6 283.2 286.1
10,260.6 11.189.9 11,s15.2 11,650.8 11,891.1 11,223.3 9,378.8 11,122.4 10.824.3 11.115.5
29.930 29,366 29 457 28,032 26,482 26,276 27,978 25,948 26,163 25,739 I
U.S. Department o f Commerce, Bureau o f t h e Census, Annual Survey o f Manufactures; American T e x t i l e Manufacturers I n s t i t u t e , T e x t i l e H i L i t e s , March 1988.
6-24
ELECTRICITY USE I N THE TEXTILE INDUSTRY E l e c t r i c i t y consumption represents about 31 percent o f t h e i n d u s t r y ' s t o t a l energy
use, making e l e c t r i c i t y t h e l a r g e s t energy supply source i n t h i s i n d u s t r y (Figure B7). The t e x t i l e i n d u s t r y consumed about 28.5 b i l l i o n kWh i n 1987. o f the e l e c t r i c i t y consumed was purchased. self-generated.
More than 98 percent Only a small share o f e l e c t r i c i t y was
Cogeneration i s a t e c h n i c a l l y v i a b l e o p t i o n f o r meeting some o f the
i n d u s t r y ' s e l e c t r i c needs, due t o the l a r g e amounts o f process steam r e q u i r e d f o r d r y i n g and f i n i s h i n g , the existence o f waste products ( f i b e r s t h a t can be i n c i n e r a t e d ) , and t h e presence o f waste heat.
However, many t e x t i l e p l a n t s are
small establishments which may not be able t o a f f o r d t h e c a p i t a l investment required t o cogenerdte. Table B-11 shows e l e c t r i c i t y consumption patterns i n t h e t e x t i l e i n d u s t r y between 1980 and 1987. Both self-generated and purchased e l e c t r i c i t y consumption increased about 9 percent between 1980 and 1987. Manmade f i b e r weaving ( S I C 222) and yarn and thread m i l l s
i n t h e t e x t i l e industry.
(SIC 228) are t h e l a r g e s t e l e c t r i c i t y consumers
The combined e l e c t r i c i t y consumption f o r the two
i n d u s t r i e s amounted t o 14.8 b i l l i o n kWh i n 1987, o r 52 percent o f t h e t o t a l e l e c t r i c i t y use i n the t e x t i l e i n d u s t r y . These two i n d u s t r i e s should be targeted by u t i l i t i e s f o r t h e promotion o f electrotechnologies t h a t improve e f f i c i e n c y ' because they stand t o g a i n t h e most from e f f i c i e n t use o f e l e c t r i c i t y .
End-Uses o f E l e c t r i c i t y The main end uses o f e l e c t r i c i t y i n t h e t e x t i l e m i l l i n d u s t r y are motor d r i v e , l i g h t i n g , and process heat. As shown i n Figure 8-8, motor d r i v e accounts f o r 83 percent o f t h e e l e c t r i c i t y consumed i n t h e t e x t i l e m i l l industry. L i g h t i n g i s the next l a r g e s t e l e c t r i c i t y consumer, w i t h process heating a p p l i c a t i o n s representing o n l y about 2 percent. Motor d r i v e e l e c t r i c i t y use i s broken down i n t o m a t e r i a l s processing (45 percent), m a t e r i a l s handling (35 percent), and pumps, fans, and compressors (about 20 percent). MuteriuZs-processing equipment performs t h e separating, combing, and other materials-processing steps t h a t are c a r r i e d out during spinning and weaving. Opening and card machinery, which use t h e i r s t e e l f i n g e r s f o r plucking and combing, and spinning machinery, which t w i s t s and separates f i b e r s , are materials-processing equipment.
8-25
Coal 10%
Source:
Figure 6-7.
1985 T e x t i l e Energy Use (286.1 T r i l l i o n Btu)
U.S. Deoartment o f Commerce. Bureau o f t h e Census. 1985 Annual Survev o f Manufactures; American Gas Association, Future Ga; Consumption i n t h e United States, Vol. 13, 1986; U.S. Department o f Energy, Energy Information Administration, Manufacture Energy Consumption Survey: Consumption o f Energy, 1985, November, 1988; and Resource Dynamics Corporation estimates. Table 6-11 ELECTRICITY CONSUMPTION I N THE TEXTILE INDUSTRY ( M i l l i o n kWh)
SIC ln&strY ..............................
221 cotton uc.vir4 222 M a m d e r i h r Ycavinp 223 Yo01 UeavinglFlnirhln 224 Y ~ W W h b d c Niilr 225 Knltting M i l k 226 Textile Finishing 227 Floor Covering Mills 228 Yam C Thread M i l l s 229 Wise. lextile
1983 1 980 1981 1982 1984 19% 1-7 1985 ............................... .......... .......... ........................... 4.758
6.4%
323 460 3.326
1.5M 1.005 6.275
c.470 6.671 339 b54
3.138 1.649 1.010 6.258 1,953
3,515
6.41111 298 317 2,918 1.891 989 5.977 1,847
3,796
3.609 7.127 336 329 3.156
3,507
2.055
1.164 7.140 2,123
1.975 1.091 6,619 2.w
2 6 . m 27.039 383 W9 26.600 26.603
25.11117 562 25.525
r.wr
298 265
3,356 2,167 9s 6.800 2.012
6.791 514 341 3,055
3.bb7 6.904 350 347 3.190 2.076 1.200 7.156 2.165
3.794 7.23L 564
561 3.350 2,201 1.319 7.596 2.295
1,898 ....................................................................................................... TOTAL SELF.GEWERATE0 ELECTR PURCHASED ELECTRICITY
Source:
26.123 392 25,751
25.922 542 25,580
24.240
553
23.887
27.034
28.562
406
b28 28.134
26.628
U.S. Dept. o f Commerce, Ann , various issues; Board o f Governors o f t h e F serve S t a t i s t i c a l Releases, 1986 and 1987; Resource Dynamics Corporation estimates.
6-26
Total Electricity Use 1985 25.9 Billion kwh
-
...................... 2%
Electric Motor D r l w Apdbationt 1985 11.3 BlPbn kWh
Electrle Process Heat Applcatlonr IS86 .6 Blllon LWh
-
Figure E-8.
-
1985 Textile Industry Electricity End Uses (25.9 Billion kWh)
8-27
Muteriols-hundling a c t i v i t i e s take place throughout t e x t i l e manufacturing, s t a r t i n g from t h e r o t a t i n g fiber-opening machinery t o f i n i s h i n g , where f a b r i c i s p r i n t e d o r heat set using r o l l e r s and r o l l i n g frames.
M a t e r i a l s handling a l s o takes place
during f a b r i c formation where bales o f f i b e r are moved through t h e m i l l .
Pumps, funs, and compressors account f o r a l a r g e p o r t i o n o f t h e e l e c t r i c i t y used i n HVAC systems.
About 20 percent o f t h e energy used i n f i n i s h i n g m i l l s i s e l e c t r i c i t y , mostly t o power small motors scattered through t h e m i l l . Pumps are
used f o r f l u i d processing i n dyeing t o pump dyes, r i n s e water, and other l i q u i d s i n t o and out o f dye becks.
Fans are a l s o used i n convection ovens used f o r drying
and f i n i s h i n g and f o r blowers i n opening and blending machines. About 640 m i l l i o n kWh was used i n t e x t i l e process heat a p p l i c a t i o n s i n 1985.
About
67 percent o f e l e c t r i c i t y used i n process heating a p p l i c a t i o n s i s used f o r drying operations and t h e remainder i s used i n c u r i n g operations.
E l e c t r i c i t y Consumption by Region The m a j o r i t y o f t e x t i l e m i l l s are concentrated i n a few regions i n the U.S.
Figure
6-9 shows e l e c t r i c i t y consumption by region i n the t e x t i l e i n d u s t r y compared t o a l l other manufacturing i n d u s t r i e s .
The Southeast region ranks t h e highest i n t e x t i l e
e l e c t r i c i t y consumption. The 1985, e l e c t r i c i t y consumption i n t h i s region amounted t o 21.6 b i l l i o n kWh, representing about 84 percent o f the t o t a l energy consumed by t h e t e x t i l e i n d u s t r y i n t h e e n t i r e U.S.
T e x t i l e manufacturers i n South Carolina and
North Carolina consumed over 12 b i l l i o n kWh o f e l e c t r i c i t y . Alabama, Tennessee, and V i r g i n i a a l s o consume l a r g e amounts o f e l e c t r i c i t y . High concentrations o f t e x t i l e m i l l s i n High Point, North Carolina; G r e e n v i l l e and Spartanburg, South Carolina; and F o r t Payne, Alabama account, i n p a r t , f o r these regional trends. As a r e s u l t , the t e x t i l e loads o f u t i l i t i e s serving these regions are high. While t e x t i l e e l e c t r i c i t y use represents about 4 percent o f t h e t o t a l manufacturing s e c t o r ' s e l e c t r i c i t y consumption, i t i s 18 percent o f the manufacturing e l e c t r i c i t y load i n the Southeast and over 25 percent o f t h e manufacturing load i n t h e t h r e e l a r g e s t producing s t a t e s as shown i n Table 6-12.
6-28
Billion kWh
I
160 1 140
120 100
80 60 40
20
"
n
S. E. E.S.Cent.Mld Atl. New Eng.E.N.CentW.S.Cent. Paclflc W.N.Cent. Mount.
Region Textlles
Other Mfrg. F i g u r e 8-9.
1985 Manufacturing E l e c t r i c i t y Use By Region Table 8-12
1985 TEXTILE INDUSTRY ELECTRICITY USE I N THE SOUTHEAST
State South C a r o l i n a North C a r o l i n e Georgia Alabama Virginia Tennessee T o t a l S.E. T o t a l U.S. S.E.
=e:
X of T o t a l U.S.
Total Indu+trisl El=. Use ( M i l . kUh)
Textile Elec. Use ( M i l . kUh)
20.994 25,795 17,630 18,642 11 .am 25,568
6,037
120,433
Textile E l e c . Use Percentage Of T o t a l
Textile Shi-ts
( M i l l i o n f)
4,902 1,912 95c 934
29 27 28 10 8 4
7.776 14,113 10,997 2,560 2,956 1.476
728.004
21,617 25,887
18 4
39.874 53,277
16.5
85.5
b,877
-.__-.-_.___ __________ ---___ -_._._-.__
-_-_---__-_.._----__~~~.~-.-.~~~.~ 74.8
U.S. Dept. o f Commerce, Annual Survey o f Manufactures, 1985; Resource Dynamics Corporation estimates.
8-29
ENERGY CONSUMPTION BY S P E C I F I C PROCESSES
The importance o f energy i n t h e t e x t i l e m i l l depends on t h e t y p e o f processing t h a t i s done a t t h e m i l l - - w e t o r dry. I n general, d r y processes are e l e c t r i c i t y i n t e n s i v e w h i l e wet processes are f o s s i l energy i n t e n s i v e .
Dry Processing
The spinning, t w i s t i n g , and weaving processes performed i n these m i l l s r e q u i r e considerable amounts o f motive power. Except f o r slashing, a l l operations performed i n t h e d r y processing m i l l use e l e c t r i c i t y as t h e primary energy source.
Steam used
i n t h e s l a s h i n g o p e r a t i o n i s u s u a l l y generated by b o i l e r s b u r n i n g n a t u r a l gas, c o a l , f u e l o i l , o r o t h e r petroleum products.
E l e c t r i c i t y supplies about 80 percent o f t h e
t o t a l energy requirements i n g r e i g e m i l l (dry m i l l s ) .
There are few o p p o r t u n i t i e s
f o r f u r t h e r e l e c t r i c i t y p e n e t r a t i o n i n dry processing.
Most o f t h e increases w i l l
come from automation programs.
As more companies automate t h e i r p l a n t s and i n s t a l l computerized systems f o r process c o n t r o l , t h e i r r e l i a n c e on u n i n t e r r u p t e d e l e c t r i c
power w i l l increase, b u t o n l y s l i g h t l y . Among t h e new technology developments t h a t might increase e l e c t r i c i t y consumed t o d r i v e motors are mechanical moisture-removal devices such as vacuum e x t r a c t o r s and r o l l e r squeezers. These might be used i n g r e i g e m i l l s t o improve s l a s h i n g operations and could be a t t r a c t i v e because o f t h e i r p o t e n t i a l energy savings. Table B-13 shows energy i n p u t s , average energy consumption, and outputs f o r each o p e r a t i o n i n t h e d r y processing m i l l . As can be seen from t h i s t a b l e , t e x t u r i z i n g , spinning, and weaving are t h e processes t h a t r e q u i r e t h e l a r g e s t amounts o f e l e c t r i c i t y t o process a pound o f f i b e r . Table B-14 presents energy consumption f i g u r e s f o r u n i t operations i n t e x t i l e m i l l s . Spinning operations i n t h e manmade f i b e r weaving ( S I C 222) and yarn and t h r e a d m i l l s ( S I C 228) s e c t o r s consumed a t o t a l o f 3,879 m i l l i o n kWh--70 percent o f a l l e l e c t r i c i t y used i n s p i n n i n g i n t h e e n t i r e i n d u s t r y .
B-30
Table E-13 ENERGY CONSUMPTION I N DRY PROCESSING MILLS
ENERGY INPUTS
OPERATIOU
AVG. ENERGY CONSfflPTlON
E
Y a m preparation
1,200
E
Carding
250 caw:
BTU/lb
yarn
. 1.800
8TUllb 754 BTUllb)
98 . 323 BTUllb (avg: 163 BTUllb)
E
.
CUTWTS
trash ( w ) lap (P) short fibers. s l i v e r (p)
trash (w)
s l i v e r (p)
E
Roving
677 1,219 BTUllb (avg: 985 BTUNIlb)
E
Spinning
1,612 -20,618 yarn (P) 7.520 B T U l l b (yarn count 18.51) ( 15,965 B T U l l b Warn count 351)
roving s l i v e r s (p)
caw:
E
Texturizing 11,694 -33,400 BTUllb tsynthhetic yarns only1 (avg: 20,500 BTUllb) Yarping
E
850 BTUllb Lbslhrlpositim)
Y a r n (p)
yarn (P)
(a 5.5 Slashing
S. E
.
1.100 2,900 BTUllb c a w : tst.eanl 1,523 BTUllb) ( telec.1 800 BTUflb)
process water tu) yam (P)
............
[total]
(
Weaving
E
2,323 BTUllb)
3,540 -13,850 BTlJ/lb (avg: 5.440 BTUllb)
f a b r i c (p)
3,540 -10.860 BTUllb
f a b r i c (PI
MI
Knitting
E KEY:
outputs: Y waste p pPocess Wtplt
Inputs: E electricity
.
s
-
. .
S".t
*Fuel swpces f o r steam prwhction: n a t u r a l gas, coal, fuel o i l , a d other p t r o l n n products
Source:
American Consulting Engineers Council, I n d u s t r i a l Market & Energy Manaqement Guide: S I C 22 The T e x t i l e M i l l Products I n d u s t r y , 1985; U.S. Dept. o f Energy, The U . S . T e x t i l e I n d u s t r y : An Energy Perspective, March 1988.
-
8-31
Table 8-14 1985 ELECTRICITY CONSUMPTION BY SPECIFIC TEXTILE OPERATION ( M i l l i o n kWh)
IOf.1
=e:
1,382
810
5.531
3.8S2
l.37p
3.W8
2,570
1.971
513
3.881
2S,?d7
U.S. Dept. o f Commerce, Bureau o f t h e Census, Annual Survey o f Manufactures, 1985; U.S. Dept. of Energy, The U . S . T e x t i l e I n d u s t r y : An Energy Perspective, March 1988; American Consulting Engineers Counci 1, I n d u s t r i a l Market and Energy Management Guide: S I C 22 Textile M i l l Products Industry; Resource Dynamics Corporation estimates.
-
8-32
Wet Processing Wet processing often requires large inputs of thermal energy, mainly to heat liquids and chemical dyes and to dry and finish textiles. Process heating is dominated by fossil fuels because they can heat evenly and inexpensively with readily available technologies. In textile processing, the quantity of heat, temperature, and method of application varies widely. Some methods (such as singeing) require direct applications of open flame, eliminating the possibility of electric process heat applications. Others require steam cans or calendars for the application of heat and pressure. In all cases the application and maintenance of a certain temperature is crucial to avoid over- or under-processing. The design and application flexibility of gas equipment allows ready application of heat in those processes where heat is required. Table 6-15 presents energy inputs, average energy consumption, and outputs for individual operations in wet processing mills. Dyeing, curing, and other finishing processes require large quantities of thermal energy. As can be seen from Table 8-15, only a few wet processing operations rely on electricity. Many plants have fuel-switching capabilities to avoid dependence on one fuel source, enabling costs to be the determining factor in fuel choice. Steam and natural gas are the two major thermal energy sources for drying and finishing, with most steam being generated by coal-, oil-, or natural gas-fired boilers. In addition to steam and hot water supplied by boilers, some drying, curing, and finishing processes also require direct-fired natural gas. Current natural gas equipment in textile processes includes natural gas radiant heat, dryers, burners, cylinder dryers, curers, convection ovens, and gas burners with calendar rolls. Electrical energy requirements for space conditioning, material handling, and other systems used in wet processing are low. Figure 6-10 shows that out of the 188 trillion Btu used for process heating in 1985, 30 percent was supplied by natural gas, 29 percent by coal, 20 percent by fuel oil, and 19 percent by LPG and other fossil fuels. Electricity accounted for only about one percent. Electric heating technologies are used mainly for drying and curing. Some mills have installed RF drying equipment. Electric process heating applications in textiles grew from about 520 million kWh in 1980 to about 640 million kWh in 1985, and there appear to be opportunities for these processes to become more widely applied in the textile industry. If electric heating processes can provide the high temperatures required
8-33
Table B-15
ENERGY CONSUMPTION I N WET PROCESSING MILLS
ENERGY INPUTS
OPERATION
YARN
AVG. ENERGY CONSUUPTIOW
CUTPUTS
DYEING
. rawstosk dyein0 ard drying wg: . yarn package dyeing a r d drying
9,UO BTUllb 10,mo
process $later dyed yarn (P)
"
YOMW FABRIC DYElllG AND FIHISHIMG heat setting avg: 530 BTUllb
. . singeing . desizing . scwring . bleachins . mercerizing .. dp yr ienitwl n g . finishing . dryin9
155
"
465
I'
1,350 1,200 1,920 6,225 9,570
heat loss (u) fabric (p) exhaust, process w a t e r (u) fabric (p) process water (w) fabric (p)
" "
process water ( w ) dyed fabric (p) process uater (u) printed fabric (p) procwr "ate? (U) fabric (p) exhaust (w) fabric (P)
'I
2,730
"
3.455
"
(W)
. preparation . dyeiw . finishing . drying
process water fabric (p) exhaust (w)
tu)
FLOOR COVERINGS
. twisting
avg: 4,500 BTUlLb ( 0 0.833 Lbslhrlposition) 3.150 BTUflb
. heat Setting
heat Loss ( w ) Yarn 1 0 )
. tufting . dyeing . printing . finishing . drying -
y a m (p)
1.050
"
9.800
ne
39,000 Blulsq. yard 3,500 BTUllb 4.350 4,550 2.010
web formation/ web b r d i n g
" I'
(Mat) (dry)
;roc.;-u.ter (U) c a r p t (p) process water ( w ) carpet (p) process uater (u) c a r p t (p) process water (w) c a r p 1 (p) exhaust (w) c a r p t (p) waste adhesive, p d m r c a r p c (p)
tu)
hltplts: Y waste process Wtput p
Inputs: E electricity G natural gas S steam, Y water
. .
. . . .
*Fuel sources for s t e m production: natural gas, coal, fuel a i \ , and other p e t r o l e m prodvcts
Source:
American Consulting Engineers Council, I n d u s t r i a l Market & Enerq The T e x t i l e M i l l Products I n d u s t r y , 1385; U.S. Manaqement Guide: S I C 22 Department o f Energy, The U.S. T e x t i l e Industry: An Enerqy Perspective, March 1985.
-
8-34
Coal 29%
Fuel Oil 20% F i g u r e B-10.
=e:
1985 Process Heat Energy Sources 188 T r i l l i o n Btu
U.S. Department o f Commerce, Bureau o f t h e Census, 1985 Annual Survey o f Manufactures; American Gas A s s o c i a t i o n , Future Gas Consumption i n t h e U n i t e d S t a t e s , Vol. 13, 1986; U.S. Department o f Energy, Energy I n f o r m a t i o n A d m i n i s t r a t i o n , Manufacture Energy Consumption Survey: Consumption of Enerqv, 1985, November, 1988; and Resource Dynamics C o r p o r a t i o n estimates.
8-35
f o r d i r e c t - f i r e d processes, increase production, improve q u a l i t y , and prevent dye m i g r a t i o n , t h e y may be i n s t a l l e d . Table 6-16 presents n o n - e l e c t r i c energy consumption by i n d i v i d u a l u n i t operations. The t a b l e shows t h a t a t o t a l o f 56.1 t r i l l i o n B t u o f f u e l s were purchased i n 1985 f o r dyeing operations, t h e l a r g e s t amount o f n o n - e l e c t r i c energy consumed i n t h e ~
t e x t i l e industry.
Almost a l l o f t h i s energy goes t o heat water f o r proper dye
f i x a t i o n and t o heat r i n s e water.
K n i t t i n g m i l l s (which dye and f i n i s h k n i t goods),
f i n i s h i n g m i l l s , and c a r p e t and r u g m i l l s are among t h e l a r g e s t consumers o f f o s s i l energy used f o r dyeing.
The combined consumption o f these t h r e e m i l l s ( S I C S 225,
226, and 227) amounts t o 73 percent o f t h e t o t a l energy consumed f o r dyeing operations i n a l l t e x t i l e m i l l s .
Table 6-16 1985 NON-ELECTRIC ENERGY CONSUMPTION BY S P E C I F I C TEXTILE PROCESSES ( T r i l l i o n Btu)
5.0 0.1
0.2
2.1
0.2
0.4
1.s
2.0 2.6
1.11
=e:
5.2
0.11
20.1
0.2
1.1
0.1
L.5
13
0.6
0.6
0.1
2.5
(6.1
9.4
8.1
1.6
10.7
11.1
1.6
52.1
S.216.411.1
2.a
0.6
0.3
1.1
8,s
a.9
*.I
2.s
1.1
5.9
5.7
6.6
1.7
5.7
56.1
54.6
3b.8
0.b
rot.i
7.4 1.1
2.6 0.2
8.0
7.7
6.2
11.1
1.0
4.1
5.1
1.1
27.7
0.8
15.6
1 .I
1a.q
8.2
197.8
U . S . Dept. o f Commerce, Bureau o f t h e Census, Annual Survey o f Manufactures, 1985; U . S . Dept. o f Energy, The U.S. T e x t i l e I n d u s t r y : An Energy Perspective; American Consulting Engineers Council, I n d u s t r i a l Market and Energy Manaqement Guide: S I C 22 T e x t i l e M i l l Products I n d u s t r y ; Resource Dynamics Corporation estimates.
-
6-36
~
Appendix C TEXTILE INDUSTRY ELECTROTECHNOLOGY EQUIPMENT SUPPLIERS
i
TABLE OF CONTENTS
APPENDIX C TEXTILE INDUSTRY ELECTROTECHNOLOGY EQUIPMENT SUPPLIERS Adjustable Speed D r i v e Equipment Suppliers Heat Exchangers and Heat Recovery Equipment Suppliers I n f r a r e d Processing Equipment Suppliers I n d u s t r i a l Process Heat Pump Equipment Suppliers Microwave Heating and Drying Equipment Suppliers Radiofrequency Heating and Drying Equipment Suppliers U l t r a v i o l e t Curing Equipment Suppliers
c-1 c-3 c-4 C-6
c-7 C-8 c-9
ADJUSTABLE SPEED DRIVE EQUIPMENT SUPPLIERS A l l e n Bradley Motion Control D i v i s i o n 4300 Brown Deer Road Brown Deer, W I 53223
Magnetek Drives & Systems 16555 Ryerson Road New B e d i n , W I 53151 414-782-0200
ABB I n d u s t r i a l Systems, Inc. P.O. Box 372 Milwaukee, W I 53201 414-785-3358
Marathon E l e c t r o n i c s Avtek D r i v e D i v i s i o n 398 Beach Road Burlingame, CA 94010 415-347-3081
Oanfoss E l e c t r o n i c s 2995 Eastrock D r i v e Rockford, I L 61109 815-398-2770; 800'-432-6367
Mitsubishi Electric Sales America 800 Biermann Court Mount Prospect, I L 60056 708-298-9223
Eaton Corporation E l e c r i c Drives D i v i s i o n 3122 14th Avenue Kenosha, W I 53141 414-656-4011
Polyspede E l e c t r o n i c s Co. 6770 Twin H i l l s Avenue Dallas, TX 75231 214-363-7245
Emerson E l e c t r i c Company I n d u s t r i a l Controls D i v i s i o n 3036 A l t Boulevard Grand Island, NY 14072 716-773-2321
Reliance E l e c t r i c Co. E l e c t r i c a l Drives Group 24703 E u c l i d Avenue Cleveland, OH 44117
GE D r i v e Systems 1100 Lawrence Parkwav ,. Erie, PA 16531 814-875-2663
Ross H i l l Controls Corp. 1530 Sam Houston Pkwy North Houston, TX 77043 7 13-467 -9888
Graham Company 8800 W. Bradley Road Milwaukee, W I 53223 414-355-8800
Southcon 10901 Downs Road PO Box 410328 Charlotte, NC 28241-0328 704-393-1636
H i t a c h i America Ltd. 220 White P l a i n s Road Tarrytown, NY 10591 914-631-0600
Square D Company PO . Box -. .. 7744h -. . . Raleigh, NC 27611 919-266-8600
-
Lovejoy Incorporated 2655 Wisconsin Avenue Downers Grove, I L 60515 708-852-0500
-
T. B. Woods' Sons Company 440 N. F i f t h Avenue Chambersburg, PA 17201 717-264-7161
c-1
ADJUSTABLE SPEED DRIVE EQUIPMENT SUPPLIERS (CONTINUED) Toshiba I n t e r . Corp. 13131 W. L i t l e York Road Houston, TX 77041 713-466-0277 West inghouse E l e c t r i c Corp. Control D i v i s i o n P.O. Box 819 Oldsmar. FL 34677
c-2
HEAT EXCHANGERS AND HEAT RECOVERY EQUIPMENT SUPPLIERS A i r t e c h Systems Corp. 365 Central S t r e e t PO Box 686 Stoughton, MA 02072
617-344-0467 Morton Machine Works, Inc. PO Box 2547 300 Jackson Avenue Columbus, GA 31901
404-322-5541
c-3
INFRARED PROCESSING EQUIPMENT SUPPLIERS BBC I n d u s t r i e s , Inc. 1526 Fenpark D r i v e Fenton, MO 63026 314-343-5600
DeVi 1b i s s Company .P.O.
BOX 913 .~.
Toledo, OH 43692 800-628-1200, Ext. 735
BGK F i n i s h i n g Systems, Inc. 4131 Pheasant Ridge Drive, North Minneapolis, MN 55434 612-784-0466
Dry-Clime Lamp Corporation P.O. Box 146 S t a t e Road 46W Greensburg, I N 47240 812-663-4141
Brink, E.H. Company, Inc. 476 Grant Terrance B u f f a l o , NY 14213 716-885-0265
Eraser Company, Inc. Luxtherm D i v i s i o n Oliva Drive P.O. Box 4961 Syracuse, NY 13221 315-454-3237
Brown Engineering 550 South Monroe S t r e e t S e a t t l e , WA 98108 206-762-7337 800-426-6384
F o s t o r i a I n d u s t r i e s , Inc. 1200 North Main S t r e e t Fostoria, OH 44830 419-435-9201
Caloritech, Inc. P.O. Box 846 Glen Burnie, MD 21061 301-766-6333
Glenro, Inc. 39 McBride Avenue Paterson, NJ 07501 800-922-0106;201-274-5900
Casso-Solar Corporation P.O. Box 163 U.S. Route 202 Pomona, NY 10970 914-356-2500
Glo-Quartz E l e c t r i c Heater Company, 1nc. 7074 Maple S t r e e t Mentor, OH 44060 216-255-9701
Chroma1ox E.L. Wiegand D i v i s i o n 641 Alpha D r i v e Pittsburgh, PA 15238 412-967-3900
Hix Corporation 1201 East 27th S t r e e t P.O. Box 393 P i t t s b u r g , KS 66762 316-231-8568
Cleveland Process Corporation 127 S.W. F i f t h Avenue Homestead, FL 33030
I n d u s t r i a l Systems Corporation 1021 Lake Road Medina. OH 44256 216-725-8500
800-241-0412;305-248-4312 Delta T Products, Inc. 22 Park Place B u t l e r , NJ 07405 201-492-1533
c-4
INFRARED PROCESSING EQUIPMENT SUPPLIERS (CONTINUED) Infrasource, Inc.
Radiation Systems, Inc.
1200-A North Concord S t r e e t South S t . Paul, MN 55075 612-450-9747
455 West Main S t r e e t Wyckoff, NJ 07481 201-891-7515
I n t e g r a t e d Technologies, Inc.
Research, Inc. Radiant Energy D i v i s i o n P.O. Box 24064 Minneapolis, MN 55424
70 M i l l Road Acushnet, MA 02743
508-998-3071
612-941-3300 J.R. Greene, Inc. 710 M y r t l e Avenue Boonton, NJ 07005
Spectrum I n f r a r e d , Inc. 246 East 131st S t r e e t Cleveland, OH 44108
201-335-1630
216-451-6666
John J. Fannon Company Thermal Devices D i v i s i o n 16025 23 M i l e Road Mount Clemens, M I 48044
Tech Systems 1013 West Main S t r e e t P.O. Box 142 Greensburo. I N 47240
313-263-8850 Mahan Oven and Engineering Co. Inc. P.O. Box 2144 Hiahwav 176E Spartanburg, SC 29304
Therma-Tech Corporation 300 Dakota S t r e e t
803-585-9433 Oal Associates, Inc. 1175 I n d u s t r i a l Avenue P.O. Box J Escondido, CA 92025
UV I11 Systems, Inc. P.O. Box 447 M i l l i s , MA 02054
619-743-7143
508-520-1802
Ogden Manufacturing Company 48 West Seeoers Road A r l i n g t o n Heights, I L 60005
Wat 1ow E l e c t r i c Manufacturing Co. 12001 Lackland Road S t . Louis, MO 63146
708-593-8050
314-878-4600
Process Thermal Dynamics, Inc. 1200 North Concord S t r e e t South S t . Paul, MN 55075
Wellman Thermal Systems Corporation One Progress Road S h e l b y v i l l e , I N 46176
612-450-4702
317-398-4411
Radiant Heat Enterprises, Inc. P.O. Box 566 4 0 ~ ~ i eai r West F a i r f i e l d , NJ 07006
201-227-6633 Radiant Heat, Inc. I n d u s t r i a l Park 62 Sawyer D r i v e Coventry, R I 02816
401-822-0360
c-5
PROCESS HEAT PUMP EQUIPMENT
INDUSTRIAL
A p p l i c a t i o n Engineering Corporation 801 AEC D r . Wood Dale, IL 60191 708-595-1060 ~~~
~~
C r i s p a i r e Corp. E-Tech D i v i s i o n 3570 American D r i v e A t l a n t a , GA 30341 404-458-6643 Dantherm Systems D i v i s i o n Patterson I n t e r n a t i o n a l 208 E. Adam S t r e e t Cambridge, W I 53523
608-423-4101;800-368-4376 Heat Exchangers, I n c . 8131 N.Monticel10 Avenue PO Box 790 Skokie, IL 60076 708-679-0300 H i t a c h i Zosen U.S.A. 150 E. 52nd S t r e e t 20th F l o o r New York, NY 10022 212-355-5650
Ltd.
McQuaylSnyderGeneral Corp. PO Box 1551 Minneapolis, MN 55440 612-553-5330 Tecogen, Inc. Thermo E l e c t r o n Corp. 45 F i r s t Avenue Waltham, MA 02254 617-622-1000
C-6
SUPPLIERS
MICROWAVE HEATING AN0 DRYING EQUIPMENT SUPPLIERS Associated Science Research Foundation 126 Water S t r e e t Marlboro NH 03455 914-335-6270 Econco Broadcast Service 1318 Commerce Avenue Woodland, CA 95695 916-662-7553; 800-0532-6626
502-241-8933 Raytheon Company 190 Willow S t r e e t Waltham, MA 02254 617-642-4244 Radio Frequency Co. Inc. 152 Dover Road PO Box 158 M i l l i s , MA 02054 617-762-4900 Watlow E l e c t r i c Mfg. Co 12001 Lackland Road S t . Louis, MO 63146 314-878-4600
c-7
RADIOFREQUENCY HEATING AND DRYING EQUIPMENT SUPPLIERS
Ameritherm, Inc. 39 Main S t r e e t S c o t t s v i l l e , NY 14546 800-456-HEAT
Radio Frequency Company, Inc. 152 Dover Road P.O. Box 158 M i l l i s , MA 02054 617-762-4900
Cal lanan 5679 Northwest Highway Chicago, I L 60646 312-792-3344
Radvne Corporation 12819 West' S i l v e r Spring Road B t .l e..r . - -u.
W..I-
53007 ...
414-mi-8360 Econco 1318 Commerce Avenue Woodland, CA 95695
Thermex Thermatron 60 Spence S t r e e t Bay Shore, NY 11706 516-231-7800
916-662-7553;800-532-6626 Glenro, Inc. 39 McBride Avenue Extension Paterson, NJ 07501 800-922-0106;201-274-5900 IHS-INOUCTOHEAT 5009 Rondo D r i v e F o r t Worth, TX 76106 817-625-5577
Inductoheat, Inc. 32251 North Avis D r i v e Madison Heights, M I 48071
800-624-6297;313-585-9393 Kabar Manufacturing Corp 140 Schmit Blvd. Farmingdale, NY 11735 516-694-6857 Nemeth Engineering Associates, Inc. 5901 West Highway 22 Crestwood, KY 40014 502-241-1502 P i l l a r I n d u s t r i e s , Inc. N92 W15800 Mega1 D r i v e Menomonee F a l l s , WE 53051 414-255-6470 PSC, Inc. 21761 Tungsten Road Cleveland, OH 44117 216-531-3375
c-8
ULTRAVIOLET CURING EQUIPMENT SUPPLIERS American U l t r a v i o l e t Co. 562 Central Avenue Murray H i l l , NJ 07974 201-665-2211 Col i g h t 820 Decatur Avenue North Minneapolis, MN 55427 612-544-9100 F u l l e r U l t r a v i o l e t Corp. PO Box 279 F r a n k f o r t , I L 60423 815-469-3301 Fusion UV Curing Systems Corp. 7600 Standish Place Rockville,MD 20855 301-251-0300 Glenro, Inc. 10 South 11th Avenue Paterson, NJ 07501 800-922-0106;201-274S5900 Hanovia, Inc. 100 Chestnut S t r e e t Newark,NJ 07105 201-589-4300 I n t e g r a t e d Technologies, Inc. 70 M i l l Road Acushnet, MA 02743 508-998-3071 Spectronics Corp. 956 Brush Hollow Road Westbury, NY 11590 516-333-4840 UV I11 Systems, Inc. P.O. Box 447 M i l l i s , MA 02054 508-520-1802
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Appendix D L
DESCRIPTIONS OF SELECTED ELECTROTECHNOLOGIES FOR THE TEXTILE INDUSTRY
7
! 7
! I
!
I
! !
~
!
! !
!
TABLE OF CONTENTS Section
APPENDIX
D
DESCRIPTIONS OF SELECTED ELECTROTECHNOLOGIES FOR THE TEXTILE INDUSTRY
D- 1
0-1 0-6 D-17 D-32 0-42
R a d i o f r e q u e n c y D r y i n g and H e a t i n g I n d u s t r i a l Process H e a t Pumps Membrane Processes U l t r a v i o l e t Curing Microwave P r o c e s s i n g
D-iii
Appendix D DESCRIPTIONS OF SELECTED ELECTROTECHNOLOGIES FOR THE TEXTILE INDUSTRY RAOIOFREQUENCY DRYING AND HEATING
B A S I C PRINCIPLES
Radiofrequency (RF) i s the name given t o the p o r t i o n o f t h e electromagnetic spectrum between 2 and 100 MHZ because these frequencies are used f o r r a d i o communications. The most commonly used RF frequencies are 13.56 and 27.12 MHZ. RF heating and drying use radio-frequency waves t o heat e l e c t r i c a l l y non-conducting m a t e r i a l s ( d i e l e c t r i c s ) composed o f p o l a r molecules.
The most common d i e l e c t r i c w i t h p o l a r
molecules i s water, and many RF a p p l i c a t i o n s are used t o d r y moist m a t e r i a l s .
Polar
molecules have an asymmetric e l e c t r i c a l structure--much l i k e m i n i a t u r e magnets--and tend t o a l i g n themselves i n an imposed e l e c t r i c f i e l d .
When the d i r e c t i o n o f the
e l e c t r i c f i e l d i s a l t e r n a t e d r a p i d l y ( a t high frequencies) these p o l a r molecules tend t o move i n synchronization w i t h the f i e l d , c r e a t i n g f r i c t i o n between molecules and thus producing heat from w i t h i n t h e material.
This p r i n c i p l e i s r e f e r r e d t o as
d i e l e c t r i c heating, and i s a l s o e x p l o i t e d by microwaves.
TEXTILE APPLICATIONS AND COMMERCIAL STATUS RF d r y i n g i s used i n t h e t e x t i l e i n d u s t r y t o dry yarn and f a b r i c s .
Specific t e x t i l e
i n d u s t r y a p p l i c a t i o n s o f RF i n c l u d e the d r y i n g o f yarn, thread tows, and f a b r i c webs.
Most t e x t i l e d r y i n g a p p l i c a t i o n s have involved b u l k yarns, i n c l u d i n g rayon
cakes and dye bobbins.
RF d r y i n g o f t h i n webs o f f a b r i c has n o t y e t been done i n a
commercial s e t t i n g .
RF d r y i n g o f warped yarns during slashing and s i z i n g operations i s c u r r e n t l y a t t h e l a b o r a t o r y stage. Since RF i s a non-contact d r y i n g method,
t h e r e are i n d i c a t i o n s t h a t t h e common problem o f s i z e m a t e r i a l s t i c k i n g t o drying c y l i n d e r s can be eliminated. f o r s i z i n g wax.
An added b e n e f i t may be a reduction o f requirements
Other RF d r y i n g b e n e f i t s i n t e x t i l e a p p l i c a t i o n s include:
0
Absence o f thermal l a g and i n e r t i a
0
Nonheating o f nonpolar f i b e r s such as p o l y e s t e r i n RF f i e l d
D- 1
Rapid drying rates Smaller drying sections of sizing machines Little or no heat radiation into the room Simple process control. By selectively heating the dielectric medium (most often water), RF produces more uniform drying in the product, while improving product quality by heating moisture and not the surface of the product. RF can be used to dry compacted materials, such as bulk yarns, which could not be dried using conventional methods. As a result, textile manufacturers can increase production volume by producing higher density yarn (more yarnlspool).
EQUIPMENT A typical RF system consists of the following four major components: A generator. Includes the power supply, voltage controls and oscillator. The power supply and voltage controls provide high-voltage power to the oscillator, which generates high-frequency power for the application. An applicator. Houses the electrode system, provides shielding and may include such auxiliaries as hot air and moisture extraction systems. The electrode system, often consisting of simple parallel plates or rods, converts the high-frequency power from the oscillator to RF waves. The applicator also contains shielding to avoid transmission of RF radiation. The materials-handling system. Positions the product under the RF applicator. In continuous-type systems, such as conveyors, the material is guided through the exposure area. Batch-type processing systems (similar to home ovens) have no materials-handling system, and depend on an operator to remove the product from the exposure area when processing is complete. The system controls. Contains the necessary controls (automatic, digital, or manual) to regulate the processing duration, intensity, and speed of the materials-handling system. The controls may be complex for special applications or may be simple on-off push buttons. Figure D-1 illustrates a textile spool-drying RF system, showing the generator, electrodes, conveyors, and extraction system.
D-2
Figure D-1. Drying of Textile Spools =e:
Reference
(2)
PERFORMANCE AND COST DATA
Power Requirements
In drying applications, a rule-of-thumb is that the power requirements are calculated at 1 kW for each kg of water removed in an hour. Thus for a bobbin of yarn weighing 1.3 kg and initially holding 26-percent moisture, an RF system removing all but 3 percent moisture (or 0.3 kg water removed) would require 03k x d
1kW
=
.
0.3kW bobbin/hr
At a production rate of 700 bobbins dried per hour, the power rating would be
x 700 bobbins
= 210
kW.
hr
Capital Costs One major disadvantage of RF is its high capital costs. The cost of an RF heater or dryer may range from $1,000 to $3,500 per kW, with smaller systems
D-3
(1 - 200 kw) ranging from $2,500 t o $3,500 p e r kW and l a r g e r systems (300 1,000 kW) ranging from $1,000 t o $2,500 per kW. The high end would be represented by a sophisticated process r e q u i r i n g complex c o n t r o l s and a p p l i c a t o r , whereas t h e low end would be t h e cost o f a simple a p p l i c a t o r . t h e 210 kW bobbin-drying system, t h e c a p i t a l cost i s $570,000.
For
Operating Costs I n s p i t e o f RF's h i g h c a p i t a l cost, a number o f t e x t i l e a p p l i c a t i o n s have proven t o be economical. However, operating costs can vary, and an examination o f c u r r e n t operating costs i s required t o evaluate t h e p o t e n t i a l benefits. Labor Costs. heat.
Labor costs are o f t e n lower w i t h RF than w i t h o t h e r forms o f Some i n s t a l l a t i o n s are equipped t o operate completely unattended. Some
i n s t a l l a t i o n s share t h e operator costs w i t h other machines o r o t h e r p a r t s o f t h e process.
I n many a p p l i c a t i o n s o n l y one operator i s required t o load and
unload. Operating l a b o r savings may be o f f s e t by increased maintenance requirements. Because o f t h e l i m i t e d l i f e o f vacuum tubes, the c r i t i c a l component o f t h e RF generator, t h e l a b o r and p a r t s required t o maintain an RF system could be significant. Enerav Costs.
Approximately 60 percent o f the power i n p u t t o the generator
a c t u a l l y reaches the product.
As a r e s u l t , t h e power r e q u i r e d i s about 1.7
times t h e power reaching t h e product, o r generator output. w i t h a 210 kW output would r e q u i r e about 350 kW power input.
Thus a generator The energy costs
o f a 210 kW RF system would be about $87,500 annually (based on 350 kW power i n p u t , 5,000 hours p e r year operation, and $0.05 per kWh). M a t e r i a l Costs. I n d r y i n g t e x t i l e s , t h e d r y i n g p e r i o d i s reduced from hours t o minutes. This n o t o n l y reduces heat d e t e r i o r a t i o n o f t h e product due t o t h e s h o r t e r time exposure, b u t a l s o reduces work i n process inventory.
Also,
t h e oven temperature need o n l y reach t h e b o i l i n g p o i n t t o remove moisture, thus t h e product i s never exposed t o h i g h heat. As a r e s u l t o f decreased exposure t o h i g h temperature, t h e amount o f product l o s s due t o overheating can be s i g n i f i c a n t l y reduced w i t h RF d r y i n g and heating.
0-4
REFERENCES: 1.
Auburn U n i v e r s i t y , Dept. o f T e x t i l e Engineering, Radio Frequency Drying o f T e x t i l e Yarns i n Sizinq, November 1987.
2.
O r f e u i l , Maurice, E l e c t r i c Process Heatinq, EPRI Report EM-5105-SR, B a t t e l l e Press, Columbus, OH 1987.
3.
Schmidt, P.S., E l e c t r i c i t y and I n d u s t r i a l P r o d u c t i v i t y , E l e c t r i c Power Research I n s t i t u t e , Report EM-3640, New York, NY, 1984.
4.
Thermo Energy Corporation, Radio-Frequency D i e l e c t r i c Heating i n Industr E l e c t r i c Power Research I n s t i t u t e , E P R I EM-4949, Palo A l t o , CA,
imidb.
D-5
INDUSTRIAL PROCESS HEAT PUMPS
BASIC PRINCIPLES Industrial process heat pumps receive process heat from low-temperature sources, elevate its temperature, and return it for process use. Heat pumps offer industries the ability to upgrade low-temperature heat and to recycle this heat back into the processes. The net effect of a well-chosen application is to reduce external energy requirements, thereby reducing costs. Heat pump cycles may be open, semi-open, or closed, depending upon the heat transfer configuration used in the process.
-
Figure D-2 is a schematic of a closed-cycle heat pump. Closed-cycle heat pumps use a working fluid, separate from the process, to transfer heat from a low-temperature source to a higher-temperature sink. The working fluid circulates through an evaporator where it is vaporized by absorbing heat from the source. A compressor is used to increase the pressure and thus the temperature of the working fluid. This fluid then passes through a condenser, where heat is transferred to the process fluid. To complete the cycle, the working fluid is then expanded to lower its pressure. Inlet I
-
I
Process
-
ounet I
Sink
t
Evaporator
t-
outlet
Heat Source-
t
Inlet
Figure D-2. Closed-Cycle Heat Pump System =e:
Reference
(2)
D-6
An open-cycle system, o f t e n c a l l e d mechanical vapor recompression (MVR), uses t h e m a t e r i a l being processed (steam o r other process vapors) d i r e c t l y as the working f l u i d , r a t h e r than t r a n s f e r r i n g heat through t h e medium o f a separate The c y c l e t h e r e f o r e eliminates heat exchangers and t h e i r associated heat t r a n s f e r i n e f f i c i e n c i e s . A schematic o f an MVR system i s shown i n Figure D-3. The process vapor (e.g., waste water) i s d e l i v e r e d refrigerant.
through an expansion device t o a f l a s h chamber where p a r t o f t h e stream i s vaporized and flows t o a compressor, which raises i t s temperature and pressure. The heated vapor d e l i v e r s i t s heat back t o t h e process, i n t h i s case as steam.
Compressed
7-
&=
rz;cs :
Campressor
' -r
bquidiCondensate Stream :n
Expansion Device
Vaporizer
rJ-"?
Flam Chamber
Heat Source
Discharge
Figure D-3.
=e:
Reference
Open-Cycle Heat Pump
(2)
A v a r i a t i o n o f t h e open-cycle system i s the semi-open system, i n which the process f l u i d i s vaporized by absorbing heat from a waste stream i n a conventional heat exchanger, then compressed t o d e l i v e r heat a t an elevated temperature.
These systems t y p i c a l l y recover heat from contaminated waste
streams.
D-7
TEXTILE APPLICATIONS AND COMMERCIAL STATUS Closed-cycle heat pumps are used in industries with relatively low temperature requirements, such as the textile industry, in applications where hotwater-driven absorption chillers are used. The textile mill industry requires large quantities of hot water for washing, dyeing, rinsing, bleaching, and scouring. A closed-cycle heat pump can recover the heat from waste water that has been used in one of these wet processing applications to heat the incoming water. Most industrial process heat pumps now in use are open-cycle systems. Open-cycle systems are finding application in industries where large quantities of water vapor are produced in evaporation, distillation, and drying processes. The textile industry uses large quantities of caustic, sodium hydroxide, and other process chemicals. Traditional steam-fired evaporators used in textile applications can be replaced with industrial process heat pumps. An open-cycle heat pump combined with an evaporative and concentrating process can recover some of these chemicals. One example is the use of a heat pump to increase the pressure of low-quality steam from a caustic soda evaporator. Semi-open-cycle systems are mostly used to recover heat from contaminated streams. Many textile drying processes rely on steam that is generated in boilers and many of the dyeing processes performed prior to drying generate large quantities of effluent. A semi-open system can recover the excess heat from waste streams and heat them for use as boiler make-up water. The main advantage of industrial process heat recovery is the reduction in energy costs. If properly placed in the industrial plant, electric heat pumps can lower operating costs by decreasing process energy requirements and reducing cooling requirements. However, their economics are highly sensitive to site-specific conditions, including relative fuel and electricity costs. Moreover, the evaluation of heat pumps should include consideration of the relative costs and benefits o f other energy conservation measures, such as increased heat integration. Heat pumps may also have other advantages. For example, compared to multipleeffect evaporators heat pump evaporators require less space and permit processing at lower temperatures, an important consideration for D-8
heat-sensitive materials, especially in those mills that process synthetic fibers or blends.
EQUIPMENT Industrial process heat recovery systems consist o f a variety o f waste recovery devices, depending on the type o f system that is being designed. Each type operates slightly differently but the end result is the same.
All industrial process heat pumps are custom designed to meet site-specific and process-specific conditions. System designs are typically prepared by architect/engineering firms or by equipment manufacturers such as evaporator suppliers. These systems may be supplied on a "turn-key" basis. As a result, it is difficult to describe a generic industrial process heat pump installation. Closed-cycle systems are typically packaged units which recover 50 to 14OoF heat and amplify it to useable temperature levels (e.g., 110 to ZOOOF). The main components o f these systems are a compressor, pressure reducing valve, and two heat exchangers (condenser and evaporator). The choice of a refrigerant (working fluid) in a closed-cycle system can be the key t o successful heat pump application.
In open-cycle systems, the compressor (and the heat exchanger in a semi-open cycle) must be compatible with the process fluids and be protected from corrosive and erosive fluids. Centrifugal compressors require that the inlet vapor be dry (superheated). Rotary screw machines can handle wet vapors and are also less sensitive to contaminated vapors. Figure D-4 is a typical system configuration for an open-cycle industrial process heat pump. The overhead vapor from a distillation vessel is compressed, raising its temperature and pressure. The high-temperature compressed gas is condensed in a heat exchanger with the bottoms product being vaporized to return the heat to the process. In an electric system the driver of the compressor is an electric motor, and in a natural gas-fired system the driver is an internal combustion engine.
D-9
Feed --#
Compressor
nottoms Product
Figure D-4. =e:
Open-Cycle Industrial Heat Pump
Reference (5) -
PERFORMANCE AND COST DATA An investment by a textile firm in an industrial process heat recovery system will be determined by the technical and economic viability of the system. From the technical standpoint, the opportunities for process heat recovery need to be assessed. The identification of industrial process heat pump utilization opportunities is complicated by the dozens of hot and cold streams that typify a wet processing operation in a textile mill. While the industrial process has been viewed as a multitude of sources and sinks offering many heat pumping possibilities, attention has typically been focused on the design of the individual unit operation at the expense of the integration of those units into an overall optimized heat flowsheet. A new analytical methodology called Pinch Analysis based on "process synthesis" techniques can be used to optimize the matching of hot and cold process streams with each other or with external utilities in a heat exchange network to reduce overall capital and operating (mainly energy) costs. Various process synthesis techniques can be applied to identify optimal heat pump
D-10
placement within the industrial plant. Only by evaluating an application in the context of overall process heat and power flows, can heat pump use be properly justified. Methodologies for achieving process integration are described in References 11, 12, 15, 17, and 18. The effectiveness of an open-cycle heat pump system is strongly dependent upon the performance of its vapor compression equipment. Generally, the desired characteristics i n a compressor include reliability, low maintenance, and high efficiency. The nature of the compression equipment varies significantly with the heat pump size and pressure ratio. Low volumetric flow rates and high pressure ratios suggest the use of positive displacement equipment such as reciprocating-piston and screw compressors. Intermediate flows and moderate pressure ratios can be accommodated by centrifugal equipment, while high flows and low pressure ratios may be best provided by axial compressors. Some process situations may require a combination of any two or all three types of compressors in order to accomplish special cycle performance. The efficiency of a heat pump i s measured by the coefficient of performance (COP), defined as the ratio of heating output to compressor work. The COP of a heat pump system should be used only as a measure of efficiency and not as a decision variable for the selection of a heat pump. The COP is dependent on: 0
Temperature difference between the heat sink and the heat source
0
Working fluid properties
0
Compressor efficiency
0
Heat exchanger effectiveness.
Capital and Operating Costs Industrial process heat pump systems are custom designed to fit specific process requirements. The economic viability of heat recovery systems is largely determined by the capital costs and operating costs (including fuel cost savings). The capital cost of a heat pump system is dependent upon many factors including system type and capacity (MBtu/hr), required temperature lift, compressor size and type, working fluid specifications, and heat exchanger(s) type and area (in closed-cycle and semi-open systems). Additional factors that directly or indirectly influence the cost o f a heat
D-11
pump system i n c l u d e t o t a l engineering time, c o s t o f c a p i t a l , p i p i n g , i n s t r u m e n t a t i o n , i n s u l a t i o n , a u x i l i a r y equipment, and i n s t a l l a t i o n . The economic r e t u r n o f a heat pump system i s very s e n s i t i v e t o s i t e - s p e c i f i c c o n d i t i o n s (i.e., technology).
pressure, temperature, u t i l i t y costs, and p r o d u c t i o n
For example, reducing steam pressure requirements o r i n c r e a s i n g
source temperature can have a s i g n i f i c a n t e f f e c t on t h e o v e r a l l system economics.
In a r e c e n t study prepared f o r t h e Department o f Energy (DOE), b o t h closedand open-cycle heat pump systems, used i n several e x i s t i n g operations, were s t u d i e d and evaluated.
Most closed-cycle heat pumps s t u d i e d used
e l e c t r i c - d r i v e systems and were moderate i n s i z e ( t y p i c a l l y l e s s than 1 t o 2 m i l l i o n Btus p e r hour). The open-cycle heat pumps ( p r i m a r i l y used i n chemical process a p p l i c a t i o n s ) were much l a r g e r systems, and used a v a r i e t y o f prime movers, i n c l u d i n g gas and steam t u r b i n e s , and e l e c t r i c motor d r i v e . Table 0-1 shows a summary o f c a p i t a l and o p e r a t i n g costs f o r t h e closed-cycle systems. The t a b l e a l s o includes payback c r i t e r i a used t o evaluate t h e p r o j e c t s .
Table
D-2 i s a summary o f t h e p r o j e c t e d c a p i t a l and o p e r a t i n g costs f o r new and r e t r o f i t MVR systems. In general, MVR systems are more expensive and r e q u i r e more engineering and design than t h e closed-cycle heat pump systems. A DOEsponsored study found t h a t a t e x t i l e company which i n s t a l l e d an MVR system i n p l a c e o f t h e e x i s t i n g c o a l - f i r e d b o i l e r s was expected t o save up t o 60 percent o f t h e p l a n t ' s f u e l costs, w i t h payback i n j u s t over one year (Reference
D-12
6).
Table D - 1 SUMMARY OF CAPITAL AND OPERATING COSTS FOR CLOSED-CYCLE HEAT PUMPS*
C a p i t a l Costs:
LOW -
Heat Pumps Other Equipment I n s t a l 1a t ion Design
$30,000 10,000 10,000 0
$
T o t a l Investment
$50,000
$3,680,000
Annual Operating and Maintenance Costs:
None Budgeted
$
Annual Energy Cost Savings:
$20,000
$1,100,000
Payback Required:
2-3 years
5-10 years
Payback Projected:
2.5 years
3.3 years
*
650,000 2,050,000 500,000 480,000
82,000
System Capacity: Range o f 100 Thousand B t u / h r t o 25 M i l l i o n B t u / h r . The s e t o f f i g u r e s r e l a t e d t o t h e "Low" end o f t h e cost range r e f l e c t s s m a l l e r system c a p a c i t i e s . The s e t o f f i g u r e s r e l a t e d t o "High" end o f t h e cost range r e f l e c t s l a r g e r system c a p a c i t i e s .
Source:
(5)
0-13
Table 0-2 SUMMARY OF PROJECTED CAPITAL COSTS FOR NEW AND RETROFIT MVR SYSTEMS* (Dollars i n Millions)
New -
Retrofit
Compression and D r i v e System
$0.75-2.3
$0.7-1.2
R e b o i l e r Condenser
$0.5-1.0
$0.9-1.1
O t h e r Equipment
$0.2-1
Installation, Engineering, and Design
$0.5-1.0
$1.3-2.0
T o t a l C a p i t a l Investment
$2.0-5.3
$3 .O-4.5
C a p i t a l Costs:
.o
$0.1-0.2
Operating and Maintenance Costs: Electricity
$0.4-1.4
$0.6-1.4
Steam
$0.8-1.5
_-
C o o l i n g Water
$0.05-0.2
$0.06-0.2
Other Expenses
$0.1-0.5
$0.30-0.5
T o t a l 0 & M Expenses
$0.5-2 .O
$1.0-2.1
$0.75-2.2
$1.0-1.5
P r o j e c t e d Energy Savings vs Conventional D i s t i l l a t i o n :
2-2.5 y e a r s
P r o j e c t e d Paybacks:
years
T o t a l s may n o t add due t o rounding and due t o t h e f a c t t h a t these c o s t s r e p r e s e n t ranges f o r t h e systems surveyed; a l s o each system may n o t have i n c o r p o r a t e d each c o s t i t e m (e.g., steam and electricity)
Note:
*
2.7-3.5
System c a p a c i t y : 20 t o 100 m i l l i o n B t u / h r . The c o s t ranges r e p o r t e d above t e n d t o r e f l e c t a t l e a s t a p o r t i o n o f t h e l i s t e d ranges of system capacities.
Source:
(5)
D-14
REFERENCES
1. A r t h u r D. L i t t l e , Inc., Heat Pumps as E f f i c i e n t I n d u s t r i a l Technoloqy, New York S t a t e Energy Research and Development A u t h o r i t y , Albany, NY, 1984.
2. E l e c t r i c Power Research I n s t i t u t e , I n d u s t r i a l Process Heat Pumps, Technical B r i e f , Palo A l t o , CA. 3. E l e c t r i c Power Research I n s t i t u t e , Heat Pump Manual, Report EM-4100-SRt Palo A l t o , CA, E l e c t r i c Power Research I n s t i t u t e and National Rural E l e c t r i c Cooperative Association, Washington, D.C., August 1985. 4.
Gas Research I n s t i t u t e , An Assessment o f Vapor Compression Heat Pumps Technology and Applications f o r I n d u s t r i a l Processes, F i n a l Report ?,November 1980-February 1982), Chicago, I L .
5. Hagler, B a i l l y , & Co., I n d u s t r i a l Heat Pump I d e n t i f i c a t i o n and Case Studies, U.S. Department o f Energy, F i n a l Report, Washington, DC, J u l y 1987. 6.
Hagler, B a i l l y Co., Opportunities f o r P r o d u c t i v i t y Improvements and Enerqy Savings i n U.S. Industry: Heat Pump Applications, U.S. Dept. o f Energy, Washington, D.C., June 1987.
7. H a r r i s , G. E.,
Heat Pumps i n D i s t i l l a t i o n Processes, EPRI EM-3656, Palo A l t o , CA, August 1984.
8. Karp, Alan, " I n d u s t r i a l Process Heat Pumps:
Some Unconventional Wisdom," paper presented t o t h e IETCE, Houston, TX, Sept. 1987.
9. O r f e u i l , Maurice, E l e c t r i c Process Heating, EPRI Report EM-5105-SR, B a t t e l l e Press, Columbus, OH, 1987. 10. Ranade, S.M., E. Hindmarsh, and D. Boland, " I n d u s t r i a l Heat Pumps: Appropriate Placement and S i z i n g Using the Grand Composite," paper presented t o t h e 8 t h I n d u s t r i a l Energy Technology Conference and E x h i b i t i o n , Houston, TX, 1986. 11. Ranade, S.M., e t . a l , " I n d u s t r i a l Heat Pumps: A Novel Approach t o Their Placement, Sizing, and Selection," paper presented t o t h e 21st IECEC, San Oiego, CA, 1986. 12. Resource Dynamics Corporation, I n d u s t r i a l Process Heat Pumps: State-of-the-Art Review and Research and Development Needs, McLean, VA, 1984.
13. Resource Dynamics Corporation, I n d u s t r i a l Process Heat Recovery, Edison E l e c t r i c I n s t i t u t e , E l e c t r i c Power Research I n s t i t u t e , September 1988. 14. Schmidt, P h i l i p S . , E l e c t r i c i t y and I n d u s t r i a l P r o d u c t i v i t y , E l e c t r i c Power Research I n s t i t u t e , Report EM-3640, Palo A l t o , CA, 1984. 15. Spriggs, H.D., and G. Ashton, "Diverse Applications o f Pinch Technology Within t h e Process I n d u s t r i e s , " paper presented t o t h e 8 t h I n d u s t r i a l Energy Technology Conference and E x h i b i t i o n , Houston, T X , 1986.
D-15
16. Tensa Technology, An Assessment o f t h e Future A p p l i c a b i l i t y o f Some Heat Engines and Heat Pumps i n t h e Process I n d u s t r i e s , Technical Papers, Middlesbrough Cleveland, England, 1981. and B. L i n n h o f f , "Using Pinch Technology f o r Process 17. Tjoe, T.N., R e t r o f i t , " Chemical Engineering, A p r i l 28, 1986.
18. Townsend, D.W., and B. Linnhoff, "Heat and Power Networks i n Process Design," AICHE Journal, Vol. 29, No. 5, 1983. 19. Union Carbide Corp., Heat Pumps i n Evaporation Processes, E l e c t r i c Power Research I n s t i t u t e , Report EM-4693, Palo A l t o , CA, November 1986.
D-16
MEMBRANE PROCESSES
BAS I C PRINCIPLES
Membrane processes use a semipermeable b a r r i e r ( t y p i c a l l y made o f an organic polymer, metal, o r ceramic) t o s e l e c t i v e l y t r a n s p o r t components from one f l u i d t o another.
The d r i v i n g f o r c e f o r the t r a n s p o r t may be pressure,
concentration, o r electromagnetic gradient. have been known f o r 200 years.
Some o f the membrane processes
The f i r s t p r a c t i c a l use o f a membrane process
was developed i n t h e e a r l y 1960's f o r seawater desalting.
By t h e e a r l y
1970's, membrane processes were commercialized and used i n waste water treatment, seawater desalting, and cheese whey separation.
Q u i t e often,
membrane separation i s overlooked although t h e p o t e n t i a l f o r energy savings i s enormous compared w i t h o t h e r separation techniques, p a r t i c u l a r l y evaporation.
In general, membrane processes do n o t i n v o l v e phase change and they are l e s s energy i n t e n s i v e than o t h e r separation processes. In phase-change separation processes, such as evaporation, d i s t i l l a t i o n , and c r y s t a l l i z a t i o n , heat i s applied o r removed from t h e s o l u t i o n t o change i t s phase t o vapor o r s o l i d On t h e o t h e r hand, membrane separation processes i n v o l v e no such
crystals.
phase change; t h e product e x i t s t h e membrane i n i t s o r i g i n a l phase.
A
combination o f conventional phase-change and membrane u n i t s are used i n h y b r i d systems capable o f operations t h a t are n o t f e a s i b l e w i t h e i t h e r process alone. Four p r i n c i p a l types o f membrane processes are used i n the i n d u s t r y , depending upon t h e physical and electrochemical p r o p e r t i e s o f the p a r t i c l e s being separated: 0
Reverse osmosis
0
U1t r a f i l t r a t i o n
0
Gas separation
0
Electrodialysis.
For t e x t i l e i n d u s t r y a p p l i c a t i o n s , reverse osmosis and u l t r a f i l t r a t i o n have proven t o be valuable and c o s t e f f e c t i v e and o n l y these two types w i l l be
0-17
discussed i n t h i s document.
The thermodynamic p r i n c i p l e s o f membrane
t r a n s p o r t are e s s e n t i a l l y the same f o r t h e d i f f e r e n t membrane processes. Reverse osmosis (RO) i s a process t h a t uses a semipermeable membrane which allows s o l u t i o n permeation, b u t acts as a b a r r i e r t o the passage, o r t r a n s p o r t , o f dissolved and suspended substances (i.e. s a l t s , ions, and organic compounds).
The s o l u t i o n t r a n s p o r t i n RO i s accomplished by using
pressure h i g h enough t o overcome t h e n a t u r a l osmotic pressure i n t h e s o l u t i o n . The p a r t i c l e s i z e o f species separated i s t y p i c a l l y between 1 t o 10 angstroms w i t h d r i v i n g pressure o f 200 t o 1000 pounds per square inch ( p s i ) . U l t r a f i l t r a t i o n (UF) i s s i m i l a r t o RO, b u t w i t h lower pressure (10-100 p s i ) and l a r g e r p a r t i c l e sizes (10 t o 299 angstroms). S o l u t i o n components r e t a i n e d (not allowed t o pass t h e membrane) depend on t h e i r molecular weight (MW); RO membranes r e t a i n species w i t h MWs up t o 300, w h i l e UF membranes r e t a i n species
with MW between 300 and 300,000. Figure D-5 i s a schematic o f t h e RO and UF processes. It shows how s a l t i s r e j e c t e d by t h e RO membrane w h i l e i t passes through t h e UF membrane.
TEXTILE APPLICATIONS AND COMMERCIAL STATUS T e x t i l e processes r e q u i r e and produce considerable q u a n t i t i e s o f hot and c o l d streams f o r various operations, as shown i n Figure D-6.
Membrane processes
are i n c r e a s i n g l y p l a y i n g an important r o l e i n t e x t i l e a p p l i c a t i o n s f o r the recovery and reuse o f valuable chemicals, organics, and process water. T e x t i l e a p p l i c a t i o n s o f membrane processes f a l l i n t o two broad categories: 0
Water p u r i f i c a t i o n
0
Waste water treatment and recovery.
0-18
Reverse Osmosis (RO)
Water
Macromolecules
Salts
-.-. 5
.*.
.:!
Permeate
:*e
~
Ultrafiltration (UF) Water
Macromolecules
Salts
2 .:;. * Figure D-5.
’
Permeatetf
Permselectivity of RO and UF Membranes
Reference (8)
=e:
Water Purification Purified water or water of a certain quality is required in many wet processing textile applications, mainly for product quality benefits. Waters used to rinse fabrics and fibers after dyeing must be of a certain quality to yield desired results, as must the boiler feed waters. Waters used in climate control systems can be pre- or post-treated using membrane systems. Textile industry process waters that can be purified with membrane separation processes include: Dye bath make-up water 0
Rinse water for higher product quality
0
Boiler feed water
0
Climate control systems.
D-19
Raw
-
Filter
Carding, Combing. Drawing Out, Roving, Spinning
Yarn -L
Hot. Xoist Exhaust Wet-End Processing Clean Fabric
Hoc, Desire Waste Scream
I
HOC, Scouring Wash Wacer
Dropped Hoc-Dye Batches
Figure D-6. =e:
Reference
-
Hot. Moist Exhaust
tI Bleaching
"Grev" FabrLc
Hot. Xoist Exhaust
t
t
Dyeing
Fabric
Hot. Bleaching Wash Water
not, m i s t Exhaust Screams "Grey" Fabric
Slashing (siring), Weaving
Washes
not Wash Water
Drying, Fixing
Finished Fabric
Generalized Schematic of Textile Treatment Processes
(2)
D-20
Waste Water Treatment and Recovery T e x t i l e wet f i n i s h i n g processes generate considerable streams c o n t a i n i n g chemical dyes, other chemicals, and heat. oxygen demand (BOD),
Many o f these have high b i o l o g i c a l r e q u i r i n g treatment p r i o r t o discharge. T h e i r reuse can
r e s u l t i n cost savings.
Membranes have been used i n t h e t e x t i l e i n d u s t r y t o
remove t h e c o l o r from waste water, separate t h e b r i n e from dyes t o be reused i n dye s e t t i n g , and recover concentrates, t e x t i l e l u b r i c a n t s , and sizes f o r reuse.
Examples o f waste water recovery and treatment a p p l i c a t i o n s include:
0
Continuous recovery (up t o 2-percent concentrations o f t e x t i l e l u b r i c a n t s w i t h high BOD f o r reuse)
0
Concentration and recovery o f dyes
0
P u r i f i c a t i o n and reuse o f i n d i g o dye
0
Recovery o f c a u s t i c wash water
0
Concentration o f p o l y v i n y l alcohol (PVA), carboxyl methyl c e l l u l o s e (CMC), and o t h e r sizes used i n slashing.
Membrane separations are normally much less energy-intensive than are conventional separations, which o f t e n i n v o l v e energy-intensive phase-change u n i t operations. I n general, they r e q u i r e o n l y e l e c t r i c a l energy t o run pumps o r compressors. The advantages o f membrane separation systems i n dyeing operations i n c l u d e consistent q u a l i t y i n t h e c o l o r o f dyes and reduced feedwater requirements.
One problem many t e x t i l e f i n i s h e r s face i s the
degradation o f dye q u a l i t y during a given production run.
Because o f the
v a r i a t i o n s i n feedwater q u a l i t y during a t y p i c a l day ( t h i s may a r i s e from overpumping, inadequately t r e a t e d feedwater, o r other reasons), dye s e t t i n g i s n o t always uniform.
This l a c k o f u n i f o r m i t y can r e s u l t i n d i f f e r e n t shades o r
hues o f f a b r i c intended t o have t h e same c o l o r .
I n some m i l l s t h e r e can be a
sharp d i s t i n c t i o n between a f a b r i c dyed i n the beginning o f t h e production run and t h a t dyed a t t h e end, although t h e same c o l o r dye was used.
When a
reverse osmosis system i s used, dye water can be t r e a t e d t o separate t h e c o l o r and p u r i f y t h e water t o i t s o r i g i n a l q u a l i t y p r i o r t o the o r i g i n a l dye setting.
Thus, no new feedwater i s required, o r what new feedwater i s
r e q u i r e d as a r e s u l t o f wastage due t o slashing would be so minimal as n o t t o a l t e r feedwater q u a l i t y .
D-21
Not all dye recovery applications of membrane processes produce these benefits, however, because some dyes may act as foulants for the membranes. When such fouling occurs on a regular basis the cost of cleaning or replacement may negate the cost effectiveness of membrane systems. In those textile processes, such as scouring, where high temperatures and waste streams containing high pH levels are produced, successful applications of membrane processes depend on the availability of high-temperature and pH-resistant membranes. The optimal separation process for many applications of membrane processes is a "hybrid" process. These processes combine a conventional separation unit operation, such as evaporation, with a membrane process, such as reverse osmosis. In some cases, separations that are not possible with either process alone may be achievable with a hybrid process. Since membrane processes are generally electric-driven, replacement of a conventional phase-change separation process with a membrane-based hybrid process usually results in the replacement of some or all thermal energy requirements by electrical energy requirements. And, due t o the relatively low energy requirements o f most membrane processes, the overall energy requirements of a membrane-based hybrid process will be lower than those of a conventional phase-change process alone. The economic benefits of membrane systems are: 0
Lower energy costs
0
Lower floor space due to compact size of membrane equipment
0
Lower design/maintenance costs due to modular design of membrane units
0
Increased productivity due to improved system reliability.
EQUIPMEN1 The basic components of a typical membrane process consist of the following components: 0
Membranes
0
Membrane modules
0
Electric liquid pump.
D-22
IIF
scour Pump Wasre ace= f o r
a 25 W C X
F i g u r e D-7. =e:
Reference
Membrane-Based Hybrid L i q u i d Separation Process
(2)
The membranes and membrane modules are t h e keys t o these systems. membrane and t h e membrane module d i f f e r among a p p l i c a t i o n s .
The type o f
Membranes are
made from a wide v a r i e t y o f m a t e r i a l s i n c l u d i n g c e l l u l o s e esters, p o l y v i n y l c h l o r i d e (PVC),
c e l l u l o s e acetate, polycarbonate, polyamides, polysulfone,
p o l y o l e f i n s , and v i n y l c h l o r i d e . The most w i d e l y used
RO membrane module c o n f i g u r a t i o n s today are: t h e
spiral-wound f l a t - s h e e t membrane; t h e s h e l l - s i d e - f e e d hol l o w - f i n e - f i b e r membrane; and t h e f l a t - e l e m e n t membrane arrangements as shown i n Figure D-8. These c o n f i g u r a t i o n s have r e l a t i v e l y h i g h packing d e n s i t i e s and a r e r e l a t i v e l y inexpensive t o i n s t a l l .
D-23
membrane; and the flat-element membrane arrangements as shown in Figure D-8. These configurations have relatively high packing densities and are relatively inexpensive to install.
Figure D-8.
=e:
References
Spiral-Wound, Hollow-Fine-Fiber, and Flat-Element Membrane
(8) D-24
A module design that is less prone to fouling than are the shell-side-feed
hollow-fine-fiber or spiral-wound modules i s the tubular-membrane module, illustrated in Figure D-9. A typical tubular membrane module consists of a number o f perforated stainless steel tubes in the form o f a shell-and-tube heat exchanger. Each tube is lined with a tubular membrane. Feed is introduced on the tube side. Turbulent flow is maintained down the length of the tubes, thereby minimizing fouling; there are no "dead spots" within the membrane module. The cost per square foot of tubular membranes, however, is typically about three times that for hollow-fiber membranes.
n Pemeate
U Parseace
InieclOutlec Ports
I
Permeate Collection Shroud
I
Pcrseace Otfcake
stainless
?lembraae
Support Tubes
/
Uembrane Insert Tubes
Figure D-9. Cross Section of a Tubular RO Membrane (A) and Schematic of a Tubular RO Membrane Module (B) =e:
Reference (2) D-25
Since most UF processes treat fouling-prone streams, UF membranes are typically modularized in tube-side-feed hollow-fiber and tubular configurations (although spiral-wound is sometimes used when less-foul ing-prone streams are treated). Module configuration also affects the ease with which the membranes can be cleaned. UF membranes can withstand solutions with high chlorine concentration, higher temperatures (close to boiling), and a wide pH range, while RO membranes have little tolerance for chlorine concentration and high temperatures (higher than 100 degrees Fahrenheit). Also, RO membranes are much more fragile than the UF ones.
PERFORMANCE AND COST DATA The selection of membrane systems depends on application requirements such as chemical and physical properties of the feed stream (i .e., feed composition, pressure, and temperature), material being separated (i .e., molecular weight and size), desired composition of the permeate and/or the concentrate, and the desired production rate (i.e., gallons per day or cubic feet per minute). While there is no standard specification for membrane equipment, it can be described in terms of pore size, rejection capability, and permeability. Pore Size: The pore structure of the membrane acts as a filter; passing small solutes while retaining larger emulsified and suspended matters. The pore size of a specific membrane should be much smaller than the size of particles rejected such that the particles cannot enter the membrane structure and plug it. Figure D-10 shows the membrane separation processes in relation t o commonly known particle sizes. Rejection: Molecular weight cut-off (defined as: the molecular weight below which a species passes through the membrane) is used as a measure of rejection. Particle rejection is influenced by many factors including pressure, pH, temperature, and solute characteristics (i.e., shape, size, and flexibility). For example, for a given molecular weight, more-rigid molecules are better rejected than flexible ones. Permeability: Permeability is defined as the volume of water permeated per unit area, time, thickness, and pressure driving force. The standard units of permeability are gallons per day (or hour) per unit area or cubic meters per day per square meter. Because both capital and operating costs for a membrane
D-26
system increase w i t h i n c r e a s i n g membrane area, i t i s important t o minimize membrane area by choosing membranes w i t h h i g h e r p e r m e a b i l i t y . Membrane l i f e depends on t h e operating c o n d i t i o n s such as process temperature, pH l e v e l , stream c h a r a c t e r i s t i c s , and c l e a n i n g and s t e r i l i z i n g c o n d i t i o n s . Generally, membrane l i f e times are two years o r more f o r t r e a t i n g clean streams (water processing), b u t are d r a s t i c a l l y reduced when t r e a t i n g comparatively d i r t y streams (i.e., waste water).
Some types o f membrane
module c o n f i g u r a t i o n s a r e more s u i t a b l e f o r c e r t a i n k i n d s o f a p p l i c a t i o n s than others.
Table 0-3 compares features f o r t h e most common membrane modules:
f l a t , t u b u l a r , spiral-wound, and h o l l o w - f i b e r membrane modules.
Typical
range
Reverse oimoiis
Mi 90% Eflicienw (3) Reflector (pamboiic or Elliptical) (4) Energy Profile (5) Cooling (Air, HIO) (6) Housing: Radialion Containment (7) ConWOr Bed
Main
-
I
t t
I
Filter
J t t
Blower
0 0
0 0 -
Substrate Positive Air Cooling
Negative Air Cooling
Radiator
Reflector Controller
(10" long 16" tall 9" wide)
-Exhaust Eiectrodeiess lamp Curing System (Fusion Systems)
Figure 0-13.
=e:
Reference
Commercial UV Processor U n i t s
(2) D-36
Table 0-4 UV
LAMP OPERATING CHARACTERISTICS
El ectrode-Act ivated Mi cruwave
=e:
Low-Pressure Mercury
Medium-Pressure Hercurv
Lamp Temp.
Cool
High
Lamp Power
1
Arc Lengths
10
Bulb Shapes
Linear, Ci rcu 1 ar
Relative System Costs
LOW
-
Flash Xenon
High
Moderate (Water Cooled)
300 Watts/In.
.1 to 10 KiloWatts Peak Power
10 Inches
.6
Linear, Curved
Linear
Linear. Circular, Hclica1
Moderate
High
High
10 Watts/In. 100
- 75 Inches
Energized Mercury
- 400 Watts/In.
1-1/2
- 77 Inches
1 - 10 Watts/In. 110 - 440 Watts/In. 550 Watts/In. Input Power Lamp Warranty 17,500 Hours 1.000 Hours 3,000 Hours
--
Major Output Wavelengths (m)
- 30 Inches
1.000 Hours
254
365. 436, 546. 580
365, 636. 546, 580
450
Spectral Variations
none
Moderate
Extensive
Limited
Spectral Efficiency
Excellent
Good
Very Good
Poor
Radiant Efficiency
Very Good
Good
Fair
Poor
Overall Efficienty
Fair
Good
Good
Poor
Practical Limits
Low Intensity
None
Limited Sizes
Low Efficiency
Reference
(2)
D-37
I n mercury lamps, t h e plasma which produces t h e UV energy i s enclosed i n a quartz envelope. This quartz envelope acts as a f i l t e r , absorbing unwanted wavelengths, e s p e c i a l l y the i n f r a r e d (IR) p o r t i o n o f t h e spectrum contained i n the lamp. F i l t e r i n g o f I R wavelengths i s important because some c u r i n g a p p l i c a t i o n s r e q u i r e t h a t substrate temperature should be maintained a t a given l e v e l . For special a p p l i c a t i o n s , e.g.,
where a high degree o f r a d i a t i o n p e n e t r a t i o n
i s required, pulsed x e n o n - f i l l e d lamps are used.
The UV s p e c t r a l output o f
the xenon lamp can be s h i f t e d by varying t h e capacitance and t h e lamp voltage. Pulsed xenon lamps can be s t a r t e d , stopped, and r e s t a r t e d i n s t a n t l y without warm up time.
Curing Speed The main advantage o f UV c u r i n g i s t h e r a p i d c u r i n g t h a t UV can e f f e c t .
Cure
speed, determined by t h e number o f UV lamps required t o cure a product a t a given l i n e speed, i s an extremely complex c a l c u l a t i o n . Q u a n t i t a t i v e t e s t s are o f t e n d i f f i c u l t t o design. factors:
Generally, c u r i n g speed depends on the f o l l o w i n g
0
The chemical depending on pigment, and manufacturer
compound. Each monomer w i l l cure a t a d i f f e r e n t r a t e , i t s composition, t h e type and amount o f s e n s i t i z e r a d d i t i v e s used. A l l o f these are determined by the o f t h e compound.
0
The thickness o f coating. The amount o f UV energy i n s i d e a l a y e r o f c o a t i n g decreases exponentially w i t h t h e depth.
0
The i n t e n s i t y o f UV energy. Up t o a c e r t a i n s a t u r a t i o n p o i n t , t h e c u r i n g r a t e increases w i t h the UV energy p e r u n i t surface area. UV cure lamps should have the highest power-to-size r a t i o a t t a i n a b l e w i t h o u t s a c r i f i c i n g t h e i r l i f e t i m e o r r e l i a b i l i t y . The shape o f a lamp's r e f l e c t o r and i t s h e i g h t above the product a f f e c t the i n t e n s i t y o f the UV energy. A r e f l e c t o r f o r which UV energy i s concentrated on a small area can a f f o r d f a s t e r c u r i n g than a r e f l e c t o r t h a t f l o o d s an area w i t h a uniform d i s t r i b u t i o n o f energy.
0
A d d i t i o n a l Factors. The method o f coat a p p l i c a t i o n , chemical f o r m u l a t i o n and substrate c h a r a c t e r i s t i c s such as type and c o l o r o f m a t e r i a l , temperature, pretreatment, and thermal capacity ( s p e c i f i c heat), can a l s o i n f l u e n c e the c u r i n g speed.
D-38
Capital Costs Complete UV system costs include the lamp system, shielding, shutters, cooling system, and installation cost. Typically, these costs are amortized over five years and represent about 25 percent of the hourly operating costs. Generally, capital cost for conventional gas curing systems are nearly four times higher than equivalent UV systems, and one-fourth of this expenditure is for the incinerator required to dispose of the solvent vapor. Since most of the UV curing systems are custom made, their prices are influenced by many factors such as type, number, and length of lamps; type of shielding; cooling method (water versus air); and type of power supply and safety interlocks. For example, water-cooled UV systems are more expensive than air cooled ones. In general, the capital cost for each type of UV lamp system i s as follows: Low-pressure mercury lamp systems have selective markets for surface curing and in some cases total curing of temperature-sensitive and troublesome substrates. A typical one-lamp low-pressure mercury system costs $215. Typical multiple-lamp systems cost anywhere between $2,700and $19,400 depending on number and lamp length. Electrodeless systems have two standard size modules (6" or lo"), and cost approximately $3,200 for the 6-inch compared to $7,500 for the 10-inch lamp module. An Xenon system complete with lamp, power supply, water cooling system, and reflector costs approximately $4,300depending upon lamp length and additional options.
Operating Costs The most significant operating costs in any curing application are material, maintenance and labor, and energy costs. Material Cost. The coating material is the most critical cost element in the UV curing applications. Coating material for UV curing applications is 1.1 to 1.75 times as expensive per pound as conventional solvent-based coatings. On the other hand, UV coating materials are entirely convertible to solids with no wasted solvent to evaporate from the coating film. This results in less coating material used per unit stock and offsets the higher price for the UV coating material. Also, since the UV-curing process is very well controlled, D-39
material loss due to the rejection of poor quality output is less than conventional curing processes. Maintenance and Labor Costs. Burned out lamps and electrical components (i.e., ballasts, magnetrons, etc.) must be periodically replaced or cleaned. Lamp replacement costs generally represent 10 to 25 percent of the total operating costs for UV systems. The normal life expectancy for most UV lamps is 1,500 hours based on one shift per day of operation. Usually, the electrodeless UV lamps have about 100 percent greater operating life than conventional electrode lamps (1,500vs. 3,000 hours for electrodeless lamps). The cost of replacement lamps varies considerably, depending on their length and type. Electrodeless lamps require the replacement of the magnetron power tubes in the 4,000- to 6,000-hour range, and cost approximately $75, whereas in conventional (electrode) lamps, ballasts are replaced and usually cost approximately $100 each. The operating labor cost for UV systems is roughly 33 percent less than that o f similar gas systems because UV systems are mechanically less complex and skilled labor is not required. Enerqy Cost. Typically, UV curing units use approximately 25 percent of the energy required by equivalent conventional gas units. Gas systems are less efficient than the UV systems. Typically, electricity represents 30-40 percent of the total operating costs.
Power Requirements Many factors influence the power requirements, such as type of substrate, lamp source, coating material, and cooling and ventilation rates. Generally, the total power required is determined by multiplying the lamp intensity (expressed in watts per inch), times the lamp length, times the total number of lamps in the system. The power required for air blowers and/or heat exchangers as well as ballast inefficiencies can generally be accounted for by including a safety factor, usually from 20-40 percent of the required power. For most ultraviolet drying applications, energy use is about 0.5 to 1 kW per inch width of substrate for each drying position in the press.
0-40
REFERENCES 1.
Baer, G.F.,"UV Curing - An Overview," SME Technical Paper FC83-248, Dearborn, M I , 1983.
2.
Battelle Columbus Laboratories, Radiation Curing: State-of-the-Art Assessment, Electric Power Research Institute, Report EM-4570, Palo K l t o , J u n e 1986.
3.
Fusion Systems, "Fusion Systems Ultraviolet Curing, Advanced Technology for Tomorrow's Benefits Today," Rockville, MD.
4.
Schmidt, Philip S . , Electricity and Industrial Productivity, Electric Power Research Institute, Report EM-4630, Palo Alto, CA, May 1983.
5.
Spero, D.M., "Choosing UV Hardware--Promises, Performances, Prices," ASM Technical Paper FC78-545, Dearborn, M I , 1978.
0-41
MICROWAVE PROCESSING
BASIC PRINCIPLES Microwave is the name given to the radio-frequency portion of the electromagnetic spectrum between 300 and 300,000 MHZ. In an effort to avoid conflict with communication applications using microwave frequencies, the Federal Communication Commission (FCC) has set aside several frequency bands for microwave heating. Of the allowed frequencies, 915 and 2,450 MHZ are used almost exclusively
.
Microwave processing uses microwaves to heat electrically non-conducting materials (dielectrics) composed of polar molecules. The most common dielectric with polar molecules is water, and many microwave applications are used to heat or dry moist materials. Polar molecules have an asymmetric electrical structure--much like miniature magnets--and tend to a1 ign themselves in an imposed electric field, as shown in Figure D-14. When the direction of the electric field is alternated rapidly (at high frequencies) these polar molecules tend to move in synchronization with the field, creating friction between molecules and thus producing heat from within the material. This principle is referred to as dielectric heating, and is also performed by radiofrequency equipment.
t.
Dipolar molecules
Alternating electric field
+
Figure D-14.
Schematic Representation of Dielectric Hysteresis Heating
D-42
Microwaves are produced by magnetron tubes, which are comprised of a rod-shaped cathode within a cylindrical anode. When power is supplied to the magnetron, electrons flow from the cathode to the anode, setting up an electromagnetic field (both electric and magnetic fields). The frequency of the field is determined by the dimensions of the slots and cavities which line the walls of the anode. When power is supplied to the magnetron, oscillations i n the slots and cavities form microwaves.
TEXTILE APPLICATIONS AND COMMERCIAL BENEFITS Textile industry applications of microwaves fall into two categories: the removal of moisture from fibers and the heating of solids and liquids used to coat, dye, or otherwise process fibers, fabrics, and floor coverings. Microwaves have been used for finished drying of carpets and to dry different samples of textile fibers (polyester and cotton fibers) and lubricants. Application of microwaves for sample testing can provide a fast and effective method of determining the moisture content of particular fabric and fiber types and their response to drying. While conventional heating provides efficient drying of products with high moisture content (microwaves can cause undesirable boil-up), microwave drying is more efficient when used to dry products with lower moisture contents. Figure D-15 illustrates how microwaves can be used to speed up drying after moisture levels drop. Microwaves have been used to reduce all the moisture from pillow stuffing to flatten these pillows for packaging. These pillows are later puffed to their original shape without any wrinkling.
antmi
n.rm
I
Figure D-15.
I
Microwave heating can effectively augment conventional heating in some applications. For example, microwave heat can pump moisture to the surlaoe 04 a product where it can be evaporated mole efficiently byaconventional hot air system. But when a product has a moisture content of 50% or more. microwave heating might cause undesirable boilina
Comparison of Microwaves and Conventional Drying
D-43
The t e x t i l e i n d u s t r y , driven almost e n t i r e l y by economics, has been slow t o respond t o microwave technology applications.
One o f the major problems w i t h
applying microwaves i n t e x t i l e a p p l i c a t i o n s i s t h e l a c k o f a d e t a i l e d assessment o f t h e economics.
Microwave equipment i s expensive from a c a p i t a l
cost standpoint. E l e c t r i c i t y i s more expensive than the o t h e r energy sources used i n t e x t i l e heating, drying, and c u r i n g applications. Microwave use i n o t h e r i n d u s t r i e s w i t h a p p l i c a t i o n s s i m i l a r t o t e x t i l e drying, f o r example, d r y i n g o f i n k s i n t h e p r i n t i n g i n d u s t r y , has demonstrated t h e convenience and speed o f microwaves.
I n a d d i t i o n t o convenience and speed, microwave
processing has been shown t o enhance p r o d u c t i v i t y because i t can heat t h i c k sections o f m a t e r i a l and heat m a t e r i a l s t h a t are s e n s i t i v e t o h i g h temperatures such as s y n t h e t i c f i b e r s and heat-sensitive dyes. Increased competition i s now f o r c i n g the t e x t i l e i n d u s t r y t o look f o r ways t o increase p r o d u c t i v i t y and decrease costs.
This has helped t o b u i l d a new
i n t e r e s t i n a v a r i e t y o f i n d u s t r i a l heating applications.
I n general,
b e n e f i t s o f microwave processing i n c l u d e increased production, decreased energy consumption, reduced m a t e r i a l loss, as w e l l as space and l a b o r savings, provided t h e a p p l i c a t i o n i s s u i t a b l e f o r microwaves.
Since the moisture l e v e l
o f f a b r i c s and f i b e r s t h a t have been d r i e d i s c r u c i a l t o t e x t i l e product q u a l i t y , t h e use o f microwaves t o measure moisture l e v e l s i n t e x t i l e products i s one valuable a p p l i c a t i o n o f microwaves i n the t e x t i l e i n d u s t r y . The comparison i n Table D-5 shows microwaves have some advantages over The reduction i n d r y i n g time can lead t o increased production volume w i t h reduced processing time. P o t e n t i a l l y successful a p p l i c a t i o n s t y p i c a l l y r e q u i r e any o f the f o l l o w i n g : conventional d r y i n g methods.
0
Heating t h i c k sections o f m a t e r i a l
0
Heating temperature-sensitive m a t e r i a l s
0
Heating expensive m a t e r i a l s w i t h reduced m a t e r i a l loss, leading t o s i g n i f i c a n t c o s t savings
0
Converting a batch process t o continuous o r semi-continuous.
D-44
Table D-5 COMPARATIVE MICROWAVE DRYING DATA
MATERIAL
T
X
Polyester Fiber Cotton F i k r T e x t i l e Lubricant
Source:
Reference
A I R OVEN DRYING
MICROYAVE D R Y I N G
Weight (9)
Moisture
Drying Tim
Moisture
(Z)
(Win)
(X)
Drying Tim (nin)
12 4
4 7 25
4
4
60
a
7 25
60
3
10
60
(2)
Microwaves have a higher power density than radiofrequency (RF) waves, and thus microwave systems g e n e r a l l y heat f a s t e r than
RF systems.
RF systems achieve a slower, more uniform heat r a t e , which i s i d e a l f o r l a r g e r , t h i c k e r
objects.
Although t h e r e i s p o t e n t i a l f o r competition between t h e two
electrotechnologies, i n most a p p l i c a t i o n s one i s b e t t e r s u i t e d than the other and g e n e r a l l y each competes against conventional ovens.
I n addition, the
average microwave system i s about 50 kW, i n contrast t o a t y p i c a l RF system, which i s about 100 300 kW. To date, t e x t i l e a p p l i c a t i o n s o f RF are more
-
v a r i e d and commercialized than those o f microwaves. Unfortunately, the t e x t i l e a p p l i c a t i o n s o f microwaves t h a t have reaped successful r e s u l t s have not been published by the companies.
For competitive
reasons t h e r e are many well-kept trade secrets i n the t e x t i l e i n d u s t r y . Laboratory t e s t s o f microwave processing i n the t e x t i l e i n d u s t r y have i n d i c a t e d some t e c h n i c a l l i m i t a t i o n s (e.g.,
dye m i g r a t i o n ) , and the high
c a p i t a l costs o f microwave equipment may pose economic b a r r i e r s . l i m i t a t i o n s are n o t insurmountable.
But these
A concerted research and development
e f f o r t together w i t h commitments from the t e x t i l e industry, microwave equipment manufacturers, and u t i l i t i e s can help accelerate the
D-45
commercialization of microwaves. In this way textile firms can realize some of the inherent benefits of microwave processing for those applications to which they are suitable.
EQUIPMENT The microwave processing system is comprised of four basic components: A generator. Includes the power supply unit and magnetron(s). The magnetron generates microwaves from electricity produced by the power supply. Prone to overheating, the magnetron is typically airor water-cooled. An applicator. Receives the microwaves from the generator and directs them to the product. The applicator consists of one or more waveguides to direct the microwaves, and can also include one-way shields that prevent microwaves from reflecting back through the waveguide, possibly damaging the magnetron. Materials Handling Equipment. Positions the product under the applicator. In continuous processing systems, the materials handling system guides the product through the exposure area. Batch processing systems (similar to home microwave ovens) have no materials handling system, and depend on an operator to remove processed products. System Controls Monitor and Regulator. To ensure adequate drying and heating while protecting against overexposure, the controls should regulate exposure time and/or material-hand1 ing speed.
PERFORMANCE AND COST DATA Prior to specifying microwave equipment, several characteristics that affect heating requirements should be known, including: Production rate (yards or feet per minute if web drying, products per hour if drying spools) 0
Material being processed
0
Weight of each product
0
Specific heat of the product
0
Desired rise in temperature
0
Dielectric properties (if application is not drying or heating water).
0-46
Determination o f Heating Requirements The f i r s t step i n s p e c i f y i n g microwave equipment i s t o determine t h e heating required by t h e a p p l i c a t i o n .
This step i s necessary t o determine the
microwave generator power requirements.
I n d r y i n g a p p l i c a t i o n s , however, the
power requirement can be estimated by using t h e percentage moisture and product weight (see next section).
There are a t most f o u r types o f heat
requirements:
1)
The heat r e q u i r e d t o r a i s e t h e dry m a t e r i a l up t o processing temperature, c a l c u l a t e d by the product o f t h e weight o f the p a r t , the s p e c i f i c heat o f the p a r t , and t h e desired r i s e i n temperature.
2)
The heat r e q u i r e d t o r a i s e the v o l a t i l e matter ( f l u i d being d r i v e n o f f , e.g., water) up t o processing temperature. The q u a n t i t y o f heat r e q u i r e d t o do so i s c a l c u l a t e d by the product o f the i n i t i a l moisture percentage, product weight, s p e c i f i c heat o f t h e v o l a t i l e , and t h e r i s e i n temperature. I n non-drying a p p l i c a t i o n s , t h i s heat i s n o t r e q u i r e d since there i s no v o l a t i l e .
3)
The heat r e q u i r e d t o vaporize ( d r i v e o f f ) t h e v o l a t i l e matter. This i s dependent on t h e heat o f vaporization o f t h e v o l a t i l e (970 B t u / l b f o r water). This q u a n t i t y o f heat i s the product o f t h e product weight,'percentage moisture, and heat o f vaporization.
4)
Heat losses t o t h e surrounding a i r o r machinery. Peak e f f i c i e n c y i s achieved when t h e product absorbs the f u l l output o f the microwave system. By c a r e f u l l y c o n f i g u r i n g the a p p l i c a t o r , t h e amount o f microwaves not absorbed by the product can be minimized.
The t o t a l heat r e q u i r e d t o d r y o r heat the a p p l i c a t i o n i s t h e sum o f these f o u r components.
By m u l t i p l y i n g by t h e production r a t e , i n products per hour,
the h o u r l y BTU requirement can be estimated.
Determination o f Power Requirements
To convert t h e heat requirements i n t o power requirements, the h o u r l y Btu requirement must be d i v i d e d by 3412 ( t h e Btu per kWh equivalent). T h i s conversion y i e l d s the generator kW output. For example, 1,000 Btu per l b i s required t o evaporate 100 l b s o f water per hour. be r e q u i r e d o r about 311 kWh.
Therefore, 100,000 Btu w i l l
This must be adjusted because o n l y a c e r t a i n
p o r t i o n o f t h e energy from the MW generator reaches the product.
I n microwave
d r y i n g a p p l i c a t i o n s , a rule-of-thumb i s t h a t the power requirements are c a l c u l a t e d a t 1 kW f o r every 2.5 l b s o f water removed per hour. Due t o the h i g h e r cost o f e l e c t r i c i t y i n comparison w i t h o t h e r energy sources, t e x t i l e
D-47
f i r m s are g e n e r a l l y w i l l i n g t o i n v e s t only i n small-sized e l e c t r i c - b a s e d equipment, g e n e r a l l y , those w i t h i n the 30-50 kW range unless the b e n e f i t s o f a l a r g e r u n i t are unequivocally demonstrated.
A p p l i c a t o r Desisn
In microwave a p p l i c a t i o n s , c o n f i g u r i n g the a p p l i c a t o r t o provide high e f f i c i e n c y , uniform, and r a p i d heating i s c r i t i c a l l y important. A p p l i c a t o r design i s a tomplex f i e l d , i n v o l v i n g t h e i n t e r a c t i o n o f heat t r a n s f e r , mass t r a n s f e r , and electromagnetics.
I n established a p p l i c a t i o n s such as bacon
cooking, pasta drying, and rubber heating, manufacturers have standard a p p l i c a t o r designs which provide h i g h l y e f f i c i e n t transmission o f t h e microwaves.
However, i n newly developed a p p l i c a t i o n s , t h e a p p l i c a t o r may
r e q u i r e a custom design.
Capital Costs One o f t h e major disadvantages o f microwave systems i s the high c a p i t a l costs. Most microwave systems cost between $2,000 and $4,000 per kW. Very l a r g e systems may c o s t l e s s p e r kW capacity. type o f operation (i.e.,
Much o f t h i s variance i s due t o t h e
batch o r continuous).
For a 40-kW u n i t ,
continuous-type systems would t y p i c a l l y cost between $100,000 t o $160,000 ( o r from $2,500 t o $4,000 per kW). The same sized u n i t may cost o n l y $50,000 f o r batch-type operation.
The continuous-type system requires a m a t e r i a l s
handling system, as w e l l as much more complex c o n t r o l s . i s about 50 kW.
A standard s i z e u n i t
Applications r e q u i r i n g 300 kW are g e n e r a l l y b e t t e r s u i t e d t o
conventional ovens due t o t h e d i f f e r e n c e i n c a p i t a l costs.
Operatinq Costs
In s p i t e o f high c a p i t a l cost, t h e r e have been a number o f a p p l i c a t i o n s where microwave d r y i n g and heating has proved t o be economical.
However, operating
cost can vary by p l a n t , and an evaluation o f c u r r e n t operating costs i s r e q u i r e d to evaluate the p o t e n t i a l b e n e f i t s o f microwave processing. Labor Costs.
Labor costs are o f t e n lower w i t h a microwave heater than w i t h conventional methods o f heating. This i s a r e s u l t o f decreased operator
involvement. In many applications only one operator is required to load and unload. Other applications may share the operator costs among several microwave heaters or with other machines. Some installations are equipped to operate completely unattended. These systems may have higher capital costs due to the automated controls necessary for unattended operation. However, any operating labor savings may be partially offset by an increase in maintenance requirements. Magnetrons, the critical component of the generator, have a limited life (requiring replacement every 6,000 hrs.). A 50-kW magnetron costs about $60,000,bringing additional maintenance charges to about $1 per hour of operation. As a result, the labor and parts required for maintenance could decrease the operating labor savings. Enerqy Costs. Approximately 50 percent of the power input to the generator actually reaches the product. As a result, the power required is about 2 times the power reaching the product, or generator output. Thus a generator with a 50-kW output would require about 100-kW power input. The energy costs o f a 50-kW microwave system would be about $44,000 annually (based on 100 kW power input, 8,760 hours per year operation--as many textile plants operate 3-shift operations 7 days a week--and $0.05 per kWh). In general, an application well suited to microwaves can save 30 to 50 percent in energy costs compared to conventional gas-fired ovens. Material Costs. One o f the major advantages of microwaves i s the increase in production or decrease in processing time. This not only reduces heat deterioration of the product due t o the shorter time exposure, but also reduces work in process inventory. Also, the oven temperature need only reach the minimum temperature (in drying applications the boiling point of water), thus the product is never exposed to high heat. As a result of.decreased exposure to high temperature, the amount of.product loss due to overheating can be significantly reduced with microwave processing. Space Savings. Microwave systems take up much less floor space than conventional ovens. Reduction in space requirements of up to 75 percent have resulted by installing microwave systems. Although sometimes difficult to quantify, the value o f reducing space requirements should be considered when evaluating microwave systems.
D-49
REFERENCES:
1.
O r f e u i l , M., E l e c t r i c Process Heatinq, EPRI Report EM-5105-SR, B a t t e l l e Press, Columbus, OH, 1987.
2.
CEM Corporation, Company brochure on Microwave S o l i d s and Moisture Analyzer, Mathews, North Carolina.
3.
Thermo Energy Corporation, Microwave Power i n Industry, E l e c t r i c Power Research I n s t i t u t e , E P R I EUM-3645, Palo A l t o , CA, August 1984.
4.
Thermo Energy Corporation, Radio-Frequency D i e l e c t r i c Heatinq i n I n d u s t r y E l e c t r i c Power Research I n s t i t u t e , Report EM-4949, Par0 A l t o , CA, Mar& 1987.
D-50
