chapter 1a - introduction to process and sustainable design

8/18/2019 Chapter 1a - Introduction to Process and Sustainable Design

1/29

EP426

Chemical Process Design and Optimization

Chapter 1


2/29

Student attainment

CLO1: Identify sustainable processes for chemicalproduction.

C4 – Assessing peer feedback and Critical evaluation of literature.

A4 – Case study, PBL, and Case summary.

P1 - Case history exercise and Case presentation.

PLO9 - ENVIRONMENT AND SUSTAINABILITY

Understand the impact of professional engineering solutions in societal andenvironmental contexts and demonstrate knowledge of and need forsustainable development.

Note:

Teaching method - Lecture & Group Project

Assessment - Test, Final Exam and report presentation.


3/29

EP426

Chemical Process Design and Optimization

Chapter 1 – Sustainable Process Design


4/29

What is Sustainability?

U.S. Environmental Protection Agency proposed thefollowing definition:

“sustainability occurs when we maintain or improve

the material and social conditions for human healthand the environment over time without exceedingthe ecological capabilities that support them”


5/29

Growing interest in sustainability

because of:

1. Increasing population, industrialization, andstandards of living.

2. Dwindling natural resources (for example, fossilfuels) and increase in the consumptions of thenon-renewable resources.

3. Global climatic changes.4. Risk to biodiversity and ecosystems.


6/29

What is Sustainability?

“triple bottom line: people, planet, and profit” - (Elkington, 1994).


7/29

Sustainable design

Sustainable design of industrial processes may bedefined as:

“the design activities that lead to economic growth,

environmental protection, and social progress for thecurrent generation without compromising the potential of future generations to have an ecosystem

that meets their needs.” - El-Halwagi, 2012


8/29

Principal objectives of a sustainable

design:

1. Resource (mass and energy) conservation

2. Recycle/reuse

3. Pollution prevention

4. Profitability enhancement

5. Yield improvement

6. Capital –productivity increase and

debottlenecking7. Quality control, assurance, and enhancement

8. Process safety


9/29

Process

Synthesis

Process

Analysis

Structure & Parameters

(unknown)

Process Output

(unknown)

Pillars of sustainable process design


10/29

Process Synthesis


11/29

Process Analysis


12/29

THE DESIGN PROCESS


13/29

Schedule The Design Process

• Primitive Design Problems

• Example

• Steps in Designing and Retrofitting Chemical Processes

• Assess Primitive Problem

• Process Creation

• Development of Base Case• Detailed Process Synthesis - Algorithmic Methods

• Process Controllability Assessment

• Detailed Design, Sizing, Cost Estimation, Optimization

• Construction, Start-up and Operation

• Environmental Protection

• Safety Considerations

Ref: Seider, Seader and Lewin (1999), Chapter 1


14/29

Primitive Design Problems

The design or retrofit of chemical processes begins with thedesire to produce profitably chemicals that satisfy societalneeds that arise in the broad spectrum of industries thatemploy chemical engineers:

– petrochemicals,

– petroleum products

– industrial gases

– foods

–pharmaceuticals

– polymers

– coatings

– electronic materials

– bio-chemicals

Note: Many design projects involve the redesign, or retrofitting , ofexisting chemical processes to solve environmental problems and to adhereto stricter standards of safety.


15/29

Steps in Process Design and Retrofit

Section A


• Development of Base-case

Section B

• Detailed Process Synthesis -AlgorithmicMethods

Section C• Plant-wide Controllability Assessment

• Detailed Design, Equipment sizing, Cap. CostEstimation, Profitability Analysis, Optimization


16/29


Assess PrimitiveProblem

Detailed Process

Synthesis -Algorithmic

Methods

Development ofBase-case

Plant-wide

ControllabilityAssessment

Detailed Design,Equipment sizing, Cap.

Cost Estimation,

Profitability Analysis,

Optimization


17/29



18/29



Development ofBase-case

Detailed Process


Methods

Plant-wide


Detailed Design,

Equipment sizing, Cap.

Cost Estimation,


Optimization

SECTION A


19/29


20/29



Development of

Base-case

Plant-wide


Detailed Design,

Equipment sizing, Cap.

Cost Estimation,


Optimization

Detailed Process


Methods

SECTION B


21/29


Section B


22/29


Development of

Base-case

Detailed Process


Methods

Detailed Design,

Equipment sizing, Cap.Cost Estimation,


Optimization

SECTION C

Plant-wide




23/29


Section C

From : Dev. of

base-case


24/29


25/29

Schedule The Design Process

• Primitive Design Problems

• Example

• Steps in Designing and Retrofitting Chemical Processes


• Process Creation

• Development of Base Case• Detailed Process Synthesis - Algorithmic Methods

• Process Controllability Assessment

• Detailed Design, Sizing, Cost Estimation, Optimization

• Construction, Start-up and Operation

• Environmental Protection

• Safety Considerations

Ref: Seider, Seader and Lewin (1999), Chapter 1

Section A

Section B

Section C

Initial

Final Design


26/29

5 Environmental Issues in Design

1. Handling of toxic wastesIt is essential that facilities be included to removepollutants from waste-water streams.

2. Reaction pathways to reduce by-product toxicity• Especially those recovered as byproducts, needs to be

evaluated.

• Pathways in large quantities of toxic should bereplaced by alternatives, except under unusualcircumstances.

3. Reducing and reusing wastes• Environmental concerns place even greater emphasis

on recycling for unreacted, product and by-productchemicals


27/29

Environmental Issues in Design ( ont’d)

4. Avoiding non-routine events

• Reduce the likelihood of accidents and spills through thereduction of transient phenomena, relying on operation at thenominal steady-state, with reliable controllers and fault-detectionsystems.

5. Design objectives, constraints and optimization

• Environmental goals often not well defined because economicobjective functions involve profitability measures, whereas thevalue of reduced pollution is often not easily quantifiedeconomically.

• Solutions: mixed objective function (“price of reduced pollution”),

or express environmental goal as “soft” or “hard” constraints.

• Environmental regulations = constraints


28/29

Design Approaches for Safety

1. Techniques to Prevent Fires and Explosions• Inerting - addition of inert dilutant to reduce the fuel

concentration below the LFL• Installation of grounding devices and anti-static devices to avoid

the buildup of static electricity• Use of explosion proof equipment•

Ensure ventilation - install sprinkler systems2. Relief Devices3. Hazard Identification and Risk Assessment

• the plant is carefully scrutinized to identify all sources of accidentsor hazards.

• Hazard and Operability (HAZOP) study is carried out, in which all

of the possible paths to an accident are identified.• when sufficient probability data are available, a fault tree is

created and the probability of the occurrence for each potentialaccident computed.


29/29

To be continued…

Chapter 1 - Hierarchical approach to process design

chapter 1a - introduction to process and sustainable design

Documents