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High Temperature High Pressure Water Gas Shift Reaction in Zeolite Membrane Reactors

Arvanitis, Antonios
http://orcid.org/0000-0001-7117-8496
http://rave.ohiolink.edu/etdc/view?acc_num=ucin1563872266361549

Abstract Details

2019, PhD, University of Cincinnati, Engineering and Applied Science: Chemical Engineering.
The water gas shift (WGS) reaction of syngas (mainly containing CO, CO2, and H2) and subsequent H2/CO2 separation are key operations for H2 production from fossil fuels, agricultural and forestry biomass, and municipal wastes with pre-combustion CO2 capture in thermal electric power production by the emerging integrated gasification-combined cycle (IGCC) power plants. Hydrogen permselective membrane reactors (MR) are capable of achieving near complete CO conversion (?CO) with simultaneous H2/CO2 separation that can substantially simplify and intensify the process to lower the overall operation cost. However, up to date, there is a lack of WGS MRs, which are practically viable either due to membrane instability in the WGS reaction of real syngas or insufficient ?CO and H2 recovery (RH2). This dissertation reports the development and scale up of thermally and chemically stable tubular zeolite membranes for future industrial high temperature and high pressure WGS MR to achieve nearly complete ?CO when nearly total RH2 is achieved in the permeate stream. An effective in-situ crystallization method has been established for synthesizing MFI-type zeolite membranes on industrially meaningful low-cost commercial porous a-alumina tube supports. The zeolite membranes with a length of 35 cm exhibited a H2/CO2 selectivity (aH2/CO2) ranging from 10 to 45 and hydrogen permeance (Pm,H2), of 1 – 2*10-7 mol/m2·Pa·s at 500oC. The WGS reaction in the single tube zeolite MR has been studied at high temperature (500oC) and high pressure (20bar) using nanocrystalline Fe-based catalysts under practically meaningful space velocities and steam-to-CO ratios. The zeolite membranes with moderate aH2/CO2 and Pm,H2, exceeded the equilibrium conversion at >500oC and achieved ?CO >99.9%. Realization of near-complete ?CO must rely on the prevention of excessive permeation of CO when the membrane has imperfect H2/CO selectivity. For the porous membranes with imperfect H2/CO permeation selectivity, such as the zeolite membranes in this research, the arrangement of catalyst loading along the membrane tube length has shown significant influences on the ?CO. For near-complete ?CO, the CO must be largely converted through the pre-membrane section so that CO partial pressure becomes sufficiently low to prevent excessive CO leak to the permeate side. A simple one-dimensional isothermal PFR model has been established for simulation of the WGS reaction in the zeolite membrane tubes with large lengths and small diameters. Both the experimental investigations and model calculations have indicated that such a distributed catalyst packing is effective for obtaining total removal of H2 and negligible escape of unreacted CO to accomplish near-complete ?CO (>99.5%). Such packing significantly improves the performance of the MR compared to the uniform packing of catalyst with the same load. Finally, because of the limited aH2/CO2, the H2 purity in the permeate stream is moderate when achieving total removal of H2 from the reaction side. A highly CO2-selective polymeric membrane unit has been integrated with the WGS MR to further remove CO2 from the H2-rich product. Results of this dissertation research showed promises for the application of the zeolite MR in the emerging IGCC plants with CCS capacity.
Junhang Dong, Ph.D. (Committee Chair)
Joo-Youp Lee, Ph.D. (Committee Member)
Peter Panagiotis Smirniotis, Ph.D. (Committee Member)
Maobing Tu, Ph.D. (Committee Member)
158 p.
Chemical Engineering
Water-Gas-Shift; Zeolites; Membrane Reactor; High Pressure; High Temperature

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Citations

  • Arvanitis, A. (2019). High Temperature High Pressure Water Gas Shift Reaction in Zeolite Membrane Reactors [Doctoral dissertation, University of Cincinnati]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1563872266361549

    APA Style (7th edition)

  • Arvanitis, Antonios. High Temperature High Pressure Water Gas Shift Reaction in Zeolite Membrane Reactors. 2019. University of Cincinnati, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=ucin1563872266361549.

    MLA Style (8th edition)

  • Arvanitis, Antonios. "High Temperature High Pressure Water Gas Shift Reaction in Zeolite Membrane Reactors." Doctoral dissertation, University of Cincinnati, 2019. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1563872266361549

    Chicago Manual of Style (17th edition)

ucin1563872266361549
174
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This open access ETD is published by University of Cincinnati and OhioLINK.