Novel Module-Based Membrane Reactor Design Approach for Improved Operability Performance

Abstract

This work aims to address the design and control challenges caused by the integration of phenomena and the loss of degrees of freedom (DOF) that occur in the intensification of membrane reactor units. First, a novel approach to designing membrane reactor units is proposed. This approach consists of designing smaller modules based on specific phenomena such as heat exchange, reactions, and mass transport and combining them in series to produce the final modular membrane-based unit. This approach to designing membrane reactors is then assessed using a process operability analysis for the first time to maximize the operability index, as a way of quantifying the operational performance of intensified processes. This work demonstrates that by designing membrane reactors in this way, the operability of the original membrane reactor design can be significantly improved, translating to an improvement in achievability for a potential control structure implementation.

Novel Module-Based Design Algorithm for Intensified Membrane Reactor Systems

“…This can be imagined as a spectrum where, on one end, there is a traditional approach with sequential unit operations that has more freedom for control but lacks efficiency, and, on the other end, there are intensified processes, such as membrane reactors, which are more efficient but lack the same freedom for control. Based on designs proposed in literature, it appears one solution might be to use a design paradigm that lies somewhere in the middle [17][18][19].…”

“…The compromise would be to propose a design that still performs membrane separation and reaction to get the benefits of the membrane reactor's efficiency, but where the unit's phenomena are decoupled to allow for more freedom for the control scheme. In previous work, the idea for modular design of membrane reactors was proposed as a potential option for this design approach [18]. This approach to designing intensified reactive distillation systems [17,20,21] and membrane reactor systems [22,23] using combinations of modules is becoming more popular in the intensification community.…”

“…The operability framework provides a great measure for determining the best modular design for addressing the degrees of freedom challenge as an increase in the servo-OI implies that a future control system will be able to achieve more points in the DOS. To demonstrate that this modular design approach could lead to an improvement in the servo-OI, a water-gas shift membrane reactor (WGS-MR) case study was explored in previous work [18]. This membrane reactor consisted of a shell and tube arrangement with a polybenzimidazole (PBI) membrane that is selective to hydrogen and highly selective to water.…”

“…The operability of a given process unit can be quantified using a metric called the operability index (OI). In previous work [18], it was demonstrated that a modular design approach could significantly improve the operability index and, therefore, gave the unit more freedom for control than it previously had. Although this was a great result, there are two challenges for solving this type of problem.…”

Reactors for Process Intensification: Recent Advances and Key Applications

“…First, B.A. Bishop and V. Lima [8] present a general overview of both design and control challenges typically occurring in membrane reactors caused by the integration of phenomena and reducing degrees of freedom. They propose a novel approach in which smaller modules based on specific phenomena (i.e., heat or mass transfer processes and chemical reactions) are consecutively combined in series to produce the final modular membrane-based unit.…”