Chemical Engineering Plant Design

Lek WanthaLecture 03

The Nature of Process Synthesis and Analysis

Creative Aspects of Process DesignIn many particular company, we might try to generate new ideal

• To produce a purchased raw material• To convert a waste by-product to a valuable product• To create a new material• To find a new way of producing an existing product• To exploit a new technology

Creative Aspects of Process Design

• Success Rates • Synthesis and analysis

• Engineering Method

• Level of engineering designs

Levels of Engineering Designs

A Hierarchical Approach to Conceptual Design

• The engineering method indicates that we should solve design problems by first developing very simple solutions and then adding successive layers of details

A Hierarchical Approach to Conceptual Design

Example: Hydrodealkylation of Toluene (HDA process)

Toluene + H2 Benzene + CH4

2Benzene Diphenyl + H2

Example: Hydrodealkylation of Toluene (HDA process)

Example: Hydrodealkylation of Toluene (HDA process) – Energy Integration

Example: Hydrodealkylation of Toluene (HDA process) – Distillation Train

Example: Hydrodealkylation of Toluene (HDA process) – Distillation Train

Example: Hydrodealkylation of Toluene (HDA process) – Vapor Recovery System

As a vapor recovery system we could use one of these:

• Condensation (high pressure, or low temperature, or both)• Absorption• Adsorption• A membrane process

Example: Hydrodealkylation of Toluene (HDA process) – Simplified Flowsheet

Example: Hydrodealkylation of Toluene (HDA process) – Recycle Structure

Example: Hydrodealkylation of Toluene (HDA process) – Input-Output Structure

Example: Hydrodealkylation of Toluene (HDA process) – Hierarchy of Decisions

1. Batch versus continuous

2. Input-output structure of the flowsheet

3. Recycle structure of the flowsheet

4. General structure of the separation system

5. Heat exchanger network