Process flow diagram

Author: Tammy Wong ^[2015]

Stewards: Jian Gong and Fengqi You

Introduction

The process flow diagram (PFD) is a critical component of process design. It is absolutely necessary that chemical engineers know how to read process flow diagrams because it is the primary method of detailing the process and design information. Additionally, the most effective way of relaying information about a process design is the use of process flow diagrams. The PFD shows the sequence of flow through a system through the various equipment (such as piping, instrumentation, and equipment design) and details the stream connections, stream flow rates and compositions and operating conditions through the plant layout. The PFD differs from a block flow diagram (BFD) in that the PFD is more detailed and conveys more information than the BFD, which only gives a general sense of flow of information.

Overview

Essential Information That Must Be Included In A Process Flow Diagram

1. Process vessels and equipment (such as heat exchangers, pumps, distillation columns, and reactors)
2. Process piping
3. Process and Utility Flow Lines
4. Full heat and material balances
5. Composition, flow rate, pressure and temperature of every stream
6. Stream enthalpy
7. Location of every control valve
8. Sizing of pumps and compressors
9. Bypass and recycle streams

Optional Information That Can Be incorporated In A Process Flow Diagram

1. Molar percentage composition and/or molar flow rates
2. Physical property data
3. Mean values for stream
4. Stream names