Semester

Spring

Date of Graduation

2022

Document Type

Dissertation

Degree Type

PhD

College

Statler College of Engineering and Mineral Resources

Department

Chemical and Biomedical Engineering

Committee Chair

Fernando V. Lima

Committee Member

Richard Turton

Committee Member

Debangsu Bhattacharyya

Committee Member

David Mebane

Committee Member

Scott Brown

Abstract

As interest in the modularization and intensification of chemical processes continues to grow, more research must be directed towards the modeling and analysis of intensified process units. Intensified process units such as membrane reactors pose unique challenges pertaining to design and operation that have not been fully addressed in the reported literature. 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 modular membrane reactor units.

First, a novel first-principles approach for modeling membrane reactors is developed using the AVEVA Process Simulation Platform’s equation-oriented capabilities. The produced model allows for the simulation of generalized membrane reactors under nonisothermal and countercurrent operation for the first time. This model is then applied to generate an operability input-output mapping to study how operating points translate to overall unit performance. This work demonstrates how operability analyses can be used to identify areas of improvement in membrane reactor design, other than just using operability mapping studies to identify optimal input conditions for process operations.

Next, 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 module-based approach to designing membrane reactors is then assessed using a process operability analysis 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 enhanced, translating to an improvement in achievability for a potential control structure implementation.

Although the demonstrated novel module-based design approach to membrane reactors could improve the operability index of membrane reactor systems, the computational time to determine such an optimal design made this class of design problems intractable to solve in a reasonable amount of time. So lastly, this work proposes a set of design heuristics for this new module-based design approach for membrane reactors. These heuristics are used in combination with a genetic algorithm to produce a novel, two-staged algorithm for the design and control of membrane reactor systems. The proposed algorithm leads to a reduction in computational time by about 2 orders of magnitude while also improving the operability index of the original membrane reactor design by 21%.

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