Analysis & Design of Common Chemical Engineering Systems

What is Analysis? ? Analysis

is the process of identifying a question or issue to be addressed, modeling the issue, investigating model results, interpreting the results, and possibly making a recommendation.

Typical analysis for process design may include: ? Market

and Technical Feasibility ? Choice of Technology (Proven, Innovative, path/ rating) ? Identification Process Equipment in the Plant ? Choice of Design theme and mode ? Availability of raw materials, utilities, human resource and process constraints ? Costs of providing the services, skills, materials, equipment, taxes and other economic issues.

Invention and Design ? INVENTION

An invention is something produced for the first time through the use of imagination or ingenious thinking and experimentation. A famous quote is: "Necessity is the mother of invention ? DESIGN

Engineering Design is like an invention to suit the unique demand of the customer (customized solutions).

What is Design? ? Design

is the human power to conceive, plan, and realize products that serve human beings in the accomplishment of any individual or collective purpose."

? Process

Design is the sizing of equipment and facilities necessary to carry out the process.

Engineering Design may require (A). Design for new process (B). Process design (C). Mechanical design (D). 3D design (E). Fabrication

(A).

Design for New Processes

– What is the Design Process? Typical five steps through which scientific principles are applied for the solution of Engineering problems are: 1. 2. 3. 4.

Define the Problem Finding solutions and ideas Documentation of ideas Testing and Refining

5. Production

Defining the Problem ? The

design process is undertaken after a specific problem or need has been identified. The identification of the problem occurs in the research and development stage of manufacturing. ? Once scientists and engineers working in R&D have identified the need for a product or discovered a problem, the design process is used to make the new product or solve the problem

The design process

The wagon...

Either fix the wheel

...broke

Or add tires so it doesn't brake again

Finding solutions and Ideas ? In

this phase, ideas are examined and a concept of the overall design is developed. ? Preliminary sketches are used to document the design and/ or computer software used for it.

One can document by hand or...

... use a CAD system

Documentation of Ideas ? In

this phase, all preliminary drawings or sketches from the previous phase are transformed into a finished package. ? Today, this is accomplished using Computer Aided Drafting and Design (CADD) systems.

To test, a computer simulation can be made ... and examined using virtual reality ....

... and a SLA/ CNC machine can be used to make a physical prototype.

Testing and Refining ? In

this phase, the design is tested in more realistic modes. This usually involves pilot plants and computer simulations for better visualization.

Machining equipment is used to mass produce the final product.

Production ?

?

In the production phase, the design is sent off to be produced. With the use of a CADD system, the data from the design is translated into a form that a Computer Aided Manufacturing (CAM) system can understand. Typical examples are CNC and CIM. Some productions processes involve Robotics as well.

(B). ? ?

?

?

Process Design

Process design is the design of processes for desired physical and/or chemical transformation of materials. The deep understanding of physical, chemical, thermodynamic properties in relation with working conditions, separation phenomena, rates of reactions, laws of transfer, transformation etc is desired. The availability of technology and kind of machinery and it’s range of applicability should be well understood. The overlapping areas of mechanical, electrical, chemical, metallurgical and civil engineering need to be well understood.

(C). ? Using

Mechanical Design

Drawing boards/CAD

(Horizontal Cylindrical Tank supported on compression load cell)

Conical Hopper

(D).

3D design

Drawing and Model

(E). ? Fabrication

Fabrication

is a specialized job jointly done by the collaboration of Chemical, Mechanical and Instrumentation engineers.

How to design

1). Mathematical Model/Equations

2). Software

3). By Analogy

1). Using Mathematical

Model/Equations (The continuity equation)

(Heat conduction equation)

(Bernoulli equation)

2).

Using Software

Design software can be categorized as : 1. Design and Draft (e.g AutoCAD) 2. Modeling and Simulation (Solid Edge, Hysys, AspinPlus, AspinDyn,PRO-II, SuperChem) 3. Analysis Software (Hysys, Asys, PRO-II)

Right software for right job !

Software Tools for Design ASPIN PLUS PIPECAD

HYSIS

CONSYD

SOLID EDGE

SOFTWARE TOOLS

TUTSIM

AUTOCAD

AUTOPLANT

MATLAB MATRIX--X MATRIX

Characteristics of Drafting Softwares ? Main

capability is Drafting

(Generate Drawings, Fabrication & Assembly Diagrams)

? Low

3-D capabilities ? Different Environments available in Software to suit Mechanical, Civil, Architecture etc. ? Fabrication details can be provided such as ( Materials, welding, grinding, Tolerances and Surface Finish information)

Characteristics of Modeling Software ? Can

generate drawings ? Can model a process for better visualization ? Models can be used with other softwares for further processing ? Can Generate machine code for fabrication

Model Visualization

Gasifier

Characteristics of Analysis Softwares ?

? ? ? ?

Requires most input from other software e. g. Drawing/Model, Material Properties, Boundary Conditions and other Computational constraints Elementary Analysis e.g. Assembly, Fixing and Alignment, Collision, Force Working in layers Integration with other software Standard procedures need to be followed in the design

(Hysys, Fluent, Asys, Aspin etc)

3).

Scale up

By Analogy

Common Chemical Engineering Systems Furnace Furnace Auxiliaries Auxiliaries Ancillaries Ancillaries

Heat Heat Exchanger Exchanger

Crystallizer Crystallizer COMMON COMMON Chemical Chemical Engg. Engg. systems systems Filters Filters

Distillation Distillation Column Column

Boiler Boiler

Tanks Tanks Vessels Vessels

Centrifuges Centrifuges Reactor Reactor

Case Study Design & Fabrication of a Down Draft Gasifier Rig

Facility Developed at Chemical Engineering, UET

Downdraft Gasifier

Wet Scrubber

Blower

Water Recirculation Tank

Recycle Pump