Solids Handling in The Chemical Company
Dr. Hermann J. Feise1) DI Thomas Letzelter2)
1) Science
Relations
2) Process
Systems Engineering
24.09.2012
1
Solids Handling Storing and Conveying of Bulk Solids
Bulk Solids Characterization Flow properties Shear testers
Design of Storage Silos Gravity fed storage systems Flow promoting devices
Conveying of Bulk Solids Screw conveyors, pneumatic conveying 24.09.2012
Dr. Hermann J. Feise, GOH/C Science Relations and Innovation Management
2
Being an Engineer in Industry The phone call 4:30 pm a customer calls
What question do you ask?
A new factory for our product „Powdery White“
…
Can you design the handling and shipping facilities for us?
…
…
… …
YES, ...... Oh, and we have two grades, the fine and the instant product.
24.09.2012
Dr. Hermann J. Feise, GOH/C Science Relations and Innovation Management
3
The Role of Particle Technology Merrow (1986): “use of solids in a process is the most prominent factor causing delayed start-up”
Merrow (1998): “things did not get better” delays of up to 18 month process predictions of solids processes are inferior to fluid - processes
Particle technology is becoming increasingly important 24.09.2012
Dr. Hermann J. Feise, GOH/C Science Relations and Innovation Management
4
Characterization of Bulk Solids: Bulk Solids are NOT like liquids Flow under gravity Surface Liquid: level Bulk solids: angle of repose Flow Liquid: incompressible
Gravel
Baking powder
Bulk solids: dilatant Storgae pressure Liquid: hydro static Bulk solids: Janssen - effect Vitamin powder
24.09.2012
Dr. Hermann J. Feise, GOH/C Science Relations and Innovation Management
Cement
5
Bulk Density – Bulk Solids Density Flow properties, packaging NOT a material constant Depends on compaction,
Feed hopper Fülltrichter
shaking, electro static conditions... Tapped density / bulk density = Hausner number Different countries – different
Bodenklappe Knife valve
Graded cylinder Meßbecher Prüfgerät zur Schüttdichtebestimmung nach DIN 53466
Device to determine the bulk density acc DIN 53466
standards – different bulk densities
24.09.2012
Dr. Hermann J. Feise, GOH/C Science Relations and Innovation Management
6
Bulk Solid Properties Janssen - Effect Janssen (1895) v A
z
Hydro static
dz
w U dz h U dz w
v
h
v + dv) A g b A dz
= lateral stress ratio = h/v x = external or wall friction angle U = circumference A = cross sectional area 24.09.2012
g b v tan x
tan D A A 1 e U 4
x U
z
w h tan x
Dr. Hermann J. Feise, GOH/C Science Relations and Innovation Management
7
Bulk Solid Properties Janssen - Effect
v A
z
dz
w U dz
v
h U dz
v + dv) A g b A dz
tan U g b A A x z e 1 v Reversion of frictional force! tan x U
24.09.2012
Dr. Hermann J. Feise, GOH/C Science Relations and Innovation Management
8
Force to Convey Millet seed Vertically through a 45 mm Acrylic Tube 250 Curve (1) Theoretical 200 Curve (2) Experimental Millet Vcon ? 30 mm/s Force - N
150
100
50
0
24.09.2012
© P. Arnold, U Wollongong
0
100
200 300 400 Column Length - mm
500
Dr. Hermann J. Feise, GOH/C Science Relations and Innovation Management
9
Bulk Solid Properties: Virtual Experiment 1 fc
Cylindrical sample with fricitonless supports Compaction with lateral support
2
Consolidation stress 1 Bulk solid density b
2
‚shear‘ 1 Consolidation
24.09.2012
fc
No lateral support Uni-axial compressive strength fc
Shear
Dr. Hermann J. Feise, GOH/C Science Relations and Innovation Management
10
Bulk Solid Properties: Ringschergerät Current industrial standard S
Ring Shear Tester RST-01pc
Tie Rod Guard Roll
Lid
N
Automatic control
Cross Bar
‚unlimited‘ travel
Guard Roll
Shear Cell
Several data points per sample
Tie Rod
Suitable for products with x95< 4 mm
S
Bulk Material
24.09.2012
Sample size: 200 bzw. 900ml
http://www.dietmar-schulze.de/fre.html
Dr. Hermann J. Feise, GOH/C Science Relations and Innovation Management
11
Shear Test Shear test vs. Travel diagram S
Over-consolidated sample Material flows under dilation travel
S
travel
Well pre-sheared sample Material flows under constand volume, no compaction
S Under – consolidated sample Material keeps compaction during shear
N =normal force, S = shear force
travel 24.09.2012
Dr. Hermann J. Feise, GOH/C Science Relations and Innovation Management
12
Test Evaluation acc. Jenike i
= internal friction angle
Shaer stres c
e = effective angle of internal friction fc = uniaxial compressive strength
1 = major principal stress (axial) 2 = minor principal stress (radial)
E
Plastic deformation
c Cohesion i
e 2
Internal friction angle 24.09.2012
fc
1 Normal stress
Dr. Hermann J. Feise, GOH/C Science Relations and Innovation Management
13
Bulk Solid Properties: Jenike Shear Cell Past industrial standard
N
Sample size: 600 ml Material requirement: 3 - 15 Liter
S
Max. travel 3 * Bmin steep 24.09.2012
steep
Less steep
Dr. Hermann J. Feise, GOH/C Science Relations and Innovation Management
25
Mass Flow Angle* % proportion odf hoppers with mass flow
100
80
axc
60
40
20
0 0°
24.09.2012
10° 20° 30° 40° Hopper angle (axial-symmetric hopper)
c
Dr. Hermann J. Feise, GOH/C Science Relations and Innovation Management
*STUDY BY TERBORG OF 500 SAMPLES
26
Flow Promotion – not this way
© BASF SE, 1999
24.09.2012
Dr. Hermann J. Feise, GOH/C Science Relations and Innovation Management
27
Silo Design: Silo Discharge for Mass Flow Flow properties
Rotary valve
ax
Storage time 4m
30°
Vibrating hopper
Silo Shape Scraper
Live Bottom 15°
0,5 24.09.2012
Dmin/D
Dr. Hermann J. Feise, GOH/C Science Relations and Innovation Management
28
Silo Design: Minimum Silo Outlet and Time consolidation Mass Flow Silo Maximum stoppage time: 3 days (week end) Continuous discharge Flow promoters conveyor Flow promoter, continuous Flow promoter after prolonged stoppage Alternative: Recycling 24.09.2012
Dmin(3 d) Gravity flow Dmin Flow promoters, short term DAus
Discharge device Conveyor
Dr. Hermann J. Feise, GOH/C Science Relations and Innovation Management
29
Mechanical Conveying: Screw Conveyors Principle:
Several feed or discharge ports
Screw helix moves through the material
Closed system (inert atmosphere)
50 - 200 rpm
No bends (exception: flexible screw conveyors)
Operational conditions L < 6 m, no intermediate bearing L < 60 m , intermediate bearing Horizontal, vertical,
Single and multiple screws Additional features Heating, cooling, mixing, homogenizing, degassing …
tilted ( 100 to/h Products Suitable for: hot, abrasive, dusty Nor sited for: cohesive, tacky Design Several feed and discharge ports horizontal up to ±5° No bends
24.09.2012
Dr. Hermann J. Feise, GOH/C Science Relations and Innovation Management
32
Material Class
1
2
3
Powder Powder sluggish sluggish adhesive 100 –
Powder sluggish fluidizes
300 mesh
3 – 325 mesh
(incl. class 1 when damp)
4
5
Granualr free-flowing
Fibrous, flaky, flocculent
>100 mesh > 25 Ib/ft3
Large particles Sizes > 3˝
Abrasive solids
High temperature
Belt conveyor Screw conv. Flex screw converyor
Vibratory conv Drag disc conv
. AeroMech Drag chain c. Redler conv Bucket elevator Plastic elevator
24.09.2012
Dr. Hermann J. Feise, GOH/C Science Relations and Innovation Management
33
Belt Conveyor
Feeder / Conveyor
Drag chain conveyor
Drag disc conveyor Screw conveyor Vibratory conveyor Aeromechanical conveyor Flexible screw conveyor Screw feeder without intermediate bearings
30 24.09.2012
Conveying60distance [m]
Dr. Hermann J. Feise, GOH/C Science Relations and Innovation Management
100
150 34
Pneumatic Conveying Principle
Product
Discharge air PI
Ambient air
Pressureized air Feed port Silo with filter unit
24.09.2012
Dr. Hermann J. Feise, GOH/C Science Relations and Innovation Management
35
Geldard diagram of fluidization
Density differnce (s – F) [kg \ m3]
10000 Group D
Diagram acc. to Geldart, boundaries acc. to Molerus
5000 2000
Group A
1000
Group B Group C
500
200 100 10
20
50
100
200
500
1000
2000 5000
Mean particle size dp [µm] 24.09.2012
Dr. Hermann J. Feise, GOH/C Science Relations and Innovation Management
36
Pneumatic Conveying States Horizontal Conveying Lean Phase Conveying Dichtstromförderung Dünnstromförderung Dense Phase Conveying Saug-or vacuum conveying oder Druckförderung pressure‐ log(log) relative pressure drop, p/l (bezogener Druckverlust/Längeneinheit)
Druckförderung Stable plug flow
24.09.2012
stabiler Vollrohr-/Kolben-
.
Instabiler Instable/ Kolbenplug Dünen-
flow
MS = 0 ruhende Granular Schüttung bed at rest
stabiler Förderbereich Stable dispersion flow Dünen/ Flugförderung Solids conveying rate Gutdurchsatz . . . . MS3MS2MS1MS0= 0
Leerlaufkurve Air only
.
pmin f) e) vmin
.
.
MS3 > MS2 > MS1
d) c)
b) a)
v* (log) mean gas velocity, v log (mittlere Gasgeschwindigkeit)
Dr. Hermann J. Feise, GOH/C Science Relations and Innovation Management
37
Pneumatic Conveying: Air flow controller Dense phase conveyor (RotoConveyor or pressure vessel system)
Almost constant air flow rate (ideal pump characteristic) at all pressure levels up to the supply pressure
p [mbar]
Laval nozzle with variable nozzle geometry
Fa. Waeschle
Suitable for explosion protection areas (no ignition sources) Can supply systems with various discharge ports and conveying distances (routing and run length)
24.09.2012
Ventilator Compressor Air flow controller
Q [m³/h]
Dr. Hermann J. Feise, GOH/C Science Relations and Innovation Management
3
Being an Engineer in Industry The phone call 4:30 pm a customer calls
What question do you ask?
A new factory for our product „Powdery White“
Product Split, Production capacity
Can you design the handling and shipping facilities for us?
Storage Volume, Storage Time
YES, ......
What do you suggest to do?
Oh, and we have two grades, the fine and the instant product.
…
Product Data
Packaging (bags, Super Sacks, loose)
… …
24.09.2012
Dr. Hermann J. Feise, GOH/C Science Relations and Innovation Management
39
