Novel Module-Based Design Algorithm for Intensified Membrane Reactor Systems

Abstract

The growing interest in intensified process units that improve efficiency by combining several phenomena into one unit, has led to a loss in degrees of freedom when addressing the control scheme of these units. Previous work demonstrated that a novel module-based design approach to membrane reactors could improve the operability index of membrane reactor systems. This approach sought to decouple the phenomena to regain some degrees of freedom for the control system. However, the computational time to determine such an optimal module design made this class of design problems intractable to solve in a reasonable amount of time. This work proposes a set of design heuristics for a new module-based design approach for membrane reactors. These heuristics are used in combination with a genetic algorithm formulation to produce a novel, two-staged algorithm for the design and control of membrane reactor systems. This algorithm is developed in Python and uses rigorous membrane reactor models built in AVEVA Process Simulation. The proposed algorithm solves the original non-polynomial (NP) complexity problem in polynomial time (P), while still being able to find the optimal designs discovered in previous work through exhaustive methods.

Dynamic Operability Analysis for Process Design and Control of Modular Natural Gas Utilization Systems

“…Each modular unit is a self-contained steel structure (i.e., a module) with integrated process equipment, pipings, instrumentations, and an integrated control system . While modular units may be more efficient due to process integration and intensification, they may have fewer operational degrees of freedom . Furthermore, the manufacturing cost of modules is typically higher than for traditional units due to the additional requirement to withstand the stress of transportation and installation.…”

“…1 While modular units may be more efficient due to process integration and intensification, they may have fewer operational degrees of freedom. 2 Furthermore, the manufacturing cost of modules is typically higher than for traditional units due to the additional requirement to withstand the stress of transportation and installation. To address these challenges, the upfront engineering of a modular unit has to ensure that it can be operated within a wide range of feed conditions while guaranteeing product specifications.…”

“…Since modular units are assembled in a factory, higher quality control is achieved, and worker safety is increased . Additionally, modularization of a process can potentially save on capital cost, deployment cost, and project timeline. − In recent years, process intensification has been combined with modularization resulting in many significant improvements in process design. , Through process intensification, new process designs with favorable scaling characteristics can be created as a means of further expanding modular manufacturing. Because an intensified modular process incorporates different phenomena (e.g., reaction, separation, heat transfer) into a single piece of equipment (e.g., membrane reactor, reactive distillation column), it is typically more efficient than its conventional counterparts.…”

“…Furthermore, modular plants are more difficult to control because of the coupling of phenomena that occurs during process intensification. This coupling of phenomena is the reason for greater efficiency in modular intensified processes, but the trade-off is fewer degrees of freedom for the controller because there are physically fewer manipulable streams and control valves in the intensified process when compared to the stand-alone units . Lastly, the dimensions of a modular unit are constrained by its means of transportation.…”

“…This coupling of phenomena is the reason for greater efficiency in modular intensified processes, but the trade-off is fewer degrees of freedom for the controller because there are physically fewer manipulable streams and control valves in the intensified process when compared to the stand-alone units. 2 Lastly, the dimensions of a modular unit are constrained by its means of transportation. For instance, when processing natural gas from the Marcellus Shale Formation around West Virginia and Pennsylvania, modular units can be shipped by road, resulting in their dimensions not exceeding those of commercial trucks.…”