Chapter 14 – Synthesis of Reactive Mass-Exchange Networks

Chapter 5, Synthesis of Mass-Exchange Networks, and Chapter 12, An Optimization Approach to Direct Recycle, covered the synthesis of physical mass-exchange networks (MENs). In these systems, the targeted species was transferred from the rich phase to the lean phase in an intact molecular form. In some cases, it may be advantageous to convert the transferred species into other compounds using reactive mass-separating agents (MSAs). Typically, reactive MSAs have a greater capacity and selectivity to remove an undesirable component than physical MSAs. Furthermore, since they react with the undesirable species, it may be possible to convert pollutants into other species that may either be reused within the plant itself or sold. The synthesis of a network of reactive mass exchangers involves the same challenges described in synthesizing physical MENs. The problem is further compounded by virtue of the reactivity of the MSAs. Driven by the need to address this important problem, Srinivas and El-Halwagi introduced the problem of synthesizing reactive mass-exchange networks (REAMENs) and developed systematic techniques for its solution. This chapter provides the basic principles of synthesizing REAMENs. The necessary thermodynamic concepts are covered. Chemical equilibrium is then tackled in a manner that renders the REAMEN synthesis task close to the MEN problem. Finally, an optimization-based approach is presented and illustrated by a case study.