(147c) Generalized Modular/Collocation Framework for Representation and Synthesis of Intensified Multi-Scale Reaction Systems

Reaction engineering, the heart of many chemical production processes, can drive radical revolutions in chemical and energy industry by designing novel catalysts and employing intensified modular reactor designs, such as micro-reaction systems, to boost volumetric or energic efficiency [1,2]. The conceptual design of chemical reactors, especially micro-reactor, normally depends on first-principle modeling with detailed descriptions on mass/heat balances and mass/heat transport with respect to specific reactor types and catalysts. However, a holistic approach to rapidly screen and systematically generate intensified and optimal reaction process alternatives by simultaneously taking into consideration multi-scale reactor options (e.g., meso- and micro- reactors) is still lacking.

A promising means to address this challenge is via the phenomena-based synthesis-intensification strategy [3-6], which represents a chemical process with fundamental building blocks without requiring any pre-postulation of plausible equipment and/or flowsheet configurations. However, key open questions remain on: (i) how to capture micro-reactors via such synthesis representation, (ii) how to capture meso- and micro- reaction systems under a unified synthesis approach, and (iii) what type of minimum process input information or data is needed to reveal the differentiation of multi-scale reactors.

In this work, we propose a synthesis representation approach for reaction systems based on the Generalized Modular Representation Framework (GMF) [7,8]. Herein, the reaction systems are represented as aggregated multifunctional mass/heat exchange modules and pure heat exchange modules to intensify the fundamental mass and/or heat transfer phenomena. Driving force constraints, derived from total Gibbs free energy change, are employed to characterize the mass transfer feasibility from a general thermodynamic perspective. Diffusion and transport rates are also incorporated into the driving force constraints to particularly account for the miniaturization effects in micro-reactors. These rate terms can be activated or de-activated respectively based on the corresponding values of Damkohler number and Thiele modulus which dictate the choice of micro- or meso- reactor size. Spatial distribution information within GMF modules is extracted via orthogonal collocation [9] in a physically compact and computationally efficient manner. A comparative case study on micro-reactor and conventional reactor for methane steam reforming [10,11] is presented to showcase the proposed approach. Extensions of catalyst impact on reactor design will also be discussed.

References

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