STUDY OF CHEMICAL PROCESS STRUCTURES FOR PROCESS SYNTHESIS

Abstract

When thermodynamic characteristics of processes are represented by a vector on the (ΔH, T₀ΔS) diagram, the processes may be classified into six types: heating, separation, refrigeration, heat source, mixing, and refrigerant. Based on this classification, which is quite appropriate to process synthesis, the analogy between chemical reactions and physical operations is discussed.
Since a chemical process system is considered to be an isolated system, the criterion for those processes to constitute a process system is examined and a new criterion based on the dissipation factor, D=T₀Δs/ΔH, is proposed. It is shown that there are only six basic patterns for the combination of processes to make up a process system.
When an endergonic process and an exergonic one constitute a process system and the former process is carried out with the help of the latter, the exergy transformation between these two processes becomes an important factor. The concept of the ideality index is introduced and the relationship between this ideality index and the dissipation factor D is discussed.