On the Design of a Dual Reflux Pressure Swing Adsorption Process

Due to the complex interaction among the process operating parameters originated by the two refluxes in dual reflux pressure swing adsorption, to foresee the influence of changes in the main operating parameters is not trivial. On one hand, the reliable rules of thumb effective to design such a process are not available. On the other hand, multi-objective optimization (MOO) algorithms coupled with detailed modeling of the process are also not viable to be used as a daily design tool since the aforementioned complexity can result in huge CPU time demand to achieve cyclic steady-state conditions. In this work, a design tool based on MOO using a properly simplified model of the unit was used to identify suitable relationships between selected target parameters (typically, product purity and energy demand) and the main operating parameters, as suggested by the equilibrium theory. These relationships allowed building a Master plot summarizing the effect of changing such operating parameters on separation performance as well as quickly identifying a small enough operating window where both the target parameters achieve the desired values. The whole procedure has been investigated and validated with reference to the separation of the binary mixture CO2–N2 as a case study.