TABLE OF CONTENTS Key Learning Objectives
How to prepare and present a process flow diagram
How to use commercial process simulation software to build a process heat and material balance model
How to use user-specified models and components when the simulator does not have what you need
How to converge flowsheets that include recycles
This chapter covers the preparation and presentation of the process flowsheet, also known as the process flow diagram (PFD). The flowsheet is the key document in process design. It shows the arrangement of the equipment selected to carry out the process, the stream connections, stream flow rates and compositions, and the operating conditions. It is a diagrammatic model of the process.
The flowsheet is used by specialist design groups as the basis for their designs. These include piping, instrumentation, and equipment design and plant layout. It is also used by operating personnel for the preparation of operating manuals and operator training. During plant startup and subsequent operation, the flowsheet forms a basis for comparison of operating performance with design.
The flowsheet is drawn up from material balances made over the complete process and each individual unit operation. Energy balances are also made to determine the energy flows and the utility requirements.
Most flowsheet calculations are carried out using commercial process simulation programs. The process simulation programs contain models for most unit operations as well as thermodynamic and physical property models. All the commercial programs feature some level of custom modeling capability that allows the designer...
