Process Synthesis

Chemical processes are usually considered to consist of a number of ?unit operations? connected together in order to transform raw materials into useful products. Traditionally, each unit operation in the process was designed and optimized individually. Unfortunately, even though each unit is optimized, the overall process may be far from optimal.

In recent years, more attention has been paid to the design of the overall process instead of individual units. In designing the overall process, the designer is faced with many challenges. The designer not only has to choose the various steps (reaction, separation, mixing etc) but also determine the best interconnection of these various steps i.e. the structure of the process. This activity of determining the structure of process is termed Process Synthesis.

Ideally, these procedures should be applied in the early stages of the design and should require minimum information since the use of rigorous design methods to evaluate alternatives can be time and capital intensive.

Process synthesis methods and tools can be applied to the design of new processes as well as to retrofit existing processes. The uses of these techniques lead to significant savings in capital and operating costs.

The Centre of Process and Material Synthesis (COMPS) has been developing new ways of synthesizing processes. A novel approach (see Figure below), which involves an interaction of both design calculations and the experimental programme has been developed. This approach allows quick and systematic generation and assessment of the large number of process alternatives.

In addition to the new approach, novel design tools and calculations, which can be applied in the early design stage, have been developed. These tools include ways of setting performance targets for processes based on fundamental principles and techniques for scanning and assessing various flowsheets. These tools have proved to be very useful in gaining insights into processes (especially in terms of integrating processes), identifying capital and operating cost saving opportunities and designing efficient and cleaner processes.