In this section, the problem of how to create, simulate, and optimize a process and how to develop a PFD is addressed. In order to create a process flow diagram, a considerable amount of information needs to be gathered. This includes reaction kinetics, thermodynamic property data, the required purity for products and byproducts, the types of separations to be used in the process, the reactor type, the range of conditions for the reaction, and many others. Once this information has been gathered, it must be synthesized into a working process. In order to accommodate the synthesis of information, the chemical engineer relies on solving material balances, energy balances, and equilibrium relationships using a process simulator. The basic data required to perform a simulation of a process are covered, and other aspects of using a process simulator are discussed. Once the PFD has been simulated, the optimization of the process can proceed. In general, process optimization involves both parametric and topological changes and both these aspects are discussed.

This material is treated in the following chapters:

      The information required to obtain a base case process flow diagram is discussed and categorized into the six basic elements of the generic block flow process diagram. The need to obtain reaction kinetics, thermodynamic data, and alternative separation methods is discussed in the context of building a base case process.

      The structure of a typical process simulator and the basic process information required to simulate a process are discussed. The various types of equipment that can be simulated, and the differences between alternative modules used to simulate similar process equipment are reviewed. The importance of choosing the correct thermodynamic package for physical property estimation is emphasized, and strategies to eliminate errors and solve simulation problems are presented.

      Basic definitions used to describe optimization problems are presented. The need to look at both topological changes in the flowsheet (rearrangement of equipment) and parametric changes (varying temperature, pressure, etc.) are emphasized. Strategies for both types of optimization are included. Special attention is paid to the integration of heat within a process. A variety of examples are given to illustrate these principles which show how optimization is applied to chemical processes.