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Dissertation Lili Sun Dec2022 F.pdf (3.59 MB)

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High Fidelity Simulations of Hollow Fiber Membrane Gas Separation Modules

Sun, Lili
http://rave.ohiolink.edu/etdc/view?acc_num=toledo1671199530904072

Abstract Details

2022, Doctor of Philosophy, University of Toledo, Engineering.
Membrane processes are the preferred option for many gas separations. Hollow fiber membranes commonly are used in these processes. Usually, ideal performance models are used to predict module performance, however, there is dramatically deviation between an ideal module and real module performance. In this work, a high fidelity simulation model is developed and used for simulating fluid flow and mass transfer in hollow fiber membrane modules. The model is used to evaluate the potential detrimental effects of: poor fiber packing along the case, potential axial diffusion, and the use of fiber tows to form the fiber bundle. The results can be used to guide carbon capture module manufacture. A full three-dimensional model is developed and used to study the effects of poor packing at the bundle-case interface. It is found that poor fiber packing near the wall is detrimental to performance. The impact increases as the size of the flow regions near the case increases. The detrimental changes to performance increase with packing fraction for a given module size (i.e., fiber number), while performance improves with increasing fiber number. To reduce the computational cost of simulating large fiber bundles, the use of an equivalent planar bundle (EPB) is proposed. A simple procedure for determining the geometry of the equivalent planar bundle is described and validated through comparisons of calculated performance metrics with results obtained from full three-dimensional simulations. Full three-dimensional models of flow and mass transfer within fiber bundles formed from tows also are developed. Results are presented illustrating the effects of varying fiber packing within a tow and the packing of tows. The results suggest smaller tows are preferred over larger tows at fixed overall fiber packing, and the inter-tow packing should be comparable to the intra-tow fiber packing. Additionally, an equivalent planar bundle (EPB) method is developed and validated that reduces computational costs compared to full three-dimensional simulations of circular bundles. To study the effects of axial diffusion on performance, 2D and 3D simulations of planar and hollow fiber modules are performed. Simulations for high performance carbon dioxide capture membranes suggest axial diffusion adversely affects module performance in certain cases. Simulations are performed for a range of material properties, module geometries, and operating conditions to determine when axial diffusion becomes significant and its impact on module performance. The conditions that lead to significant contributions from axial diffusion correlate well with a modified Peclet number.
Glenn Lipscomb (Committee Chair)
Chemical Engineering

Recommended Citations

Citations

  • Sun, L. (2022). High Fidelity Simulations of Hollow Fiber Membrane Gas Separation Modules [Doctoral dissertation, University of Toledo]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=toledo1671199530904072

    APA Style (7th edition)

  • Sun, Lili. High Fidelity Simulations of Hollow Fiber Membrane Gas Separation Modules. 2022. University of Toledo, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=toledo1671199530904072.

    MLA Style (8th edition)

  • Sun, Lili. "High Fidelity Simulations of Hollow Fiber Membrane Gas Separation Modules." Doctoral dissertation, University of Toledo, 2022. http://rave.ohiolink.edu/etdc/view?acc_num=toledo1671199530904072

    Chicago Manual of Style (17th edition)

toledo1671199530904072
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© 2022, all rights reserved.
This open access ETD is published by University of Toledo and OhioLINK.
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