High-Temperature Ceramic-Carbonate Dual-Phase Membrane Reactor for Pre-combustion Carbon Dioxide Capture (Final Scientific/Technical Report)
Arizona State University, in collaboration with University of South Carolina, worked on a project aimed at development of a new high temperature, high pressure CO2 perm-selective membrane reactor for water-gas-shift reaction (WGS) with simulated gasifier syngas to produce a high concentration H2 stream with CO2 capture. The membrane reactor is made of a CO2 semi-permeable ceramic-carbonate dual-phase (CCDP) membrane with high CO2 perm-selectivity/permeance and thermal/mechanical stability for application in WGS reaction. The objectives of this project were to (1) synthesize the chemically/thermally stable tubular CCDP membranes with CO2 permeance and selectivity (with respect to H2, CO or H2O) larger than 6.5×10-7 mol/m2·s·Pa and 500, respectively; (2) establish CCDP membrane reactor setup and study high pressure CO2 permeation and WGS reaction with CO2 capture using the setup; and (3) identify conditions for WGS in the CCDP membrane reactor that produce CO2 and H2 streams with purity of >99% and >90% respectively at CO conversion >95% and overall carbon capture >90%. The work in this project included both membrane development and membrane reactor process study. The membrane development efforts were focused on investigating a H2S resistant and highly oxygen-ionic conducting metal oxide material and membrane for CO2 separation, fabrication of tubular samaria-doped-ceria/molten-carbonate CCDP membrane with high mechanical strength, and experimental and modeling study of high-pressure CO2 permeation of the CCDP membranes. Mathematical models were developed to describe WGS in the CCDP membrane reactor without a catalyst or packed with a commercial high temperature WGS catalyst. Experiments on WGS in the CCDP membrane reactor with the commercial WGS catalyst, guided by the model analysis, were performed to identify optimum conditions for achieving the CO conversion, carbon capture, and the purity of the H2 and CO2 streams mentioned above. At 30 atm feed pressure, 750°C operation temperature, space velocity of 250 h-1, and with steam sweep, a single-stage CCDP membrane reactor with average CO2 permeation flux of 0.5 cm3(STP)/min.cm2 can achieve CO2 conversion of 95% and overall carbon capture of 94%, and produce CO2 and H2 streams with dry-based purity of >99% and 92% respectively. The project also included process design and techno-economic analysis (TEA) for a CCDP membrane reactor process for WGS reaction with CO2 capture for a 550 MW coal-fired IGCC power plant, and its comparison with the conventional fixed-bed reactor system for WGS with follow-up CO2 capture by an amine absorption process. The target performance for the reactor for WGS with CO2 capture includes CO conversion >95%, hydrogen stream purity >90%, CO2 stream purity >95%, and total carbon capture >90%. The CCDP membrane developed in this project can achieve the performance target, without subsequent CO2 capture process at the optimum conditions identified in this project. The outcome of the process design and TEA analysis shows that the membrane reactor for WGS with in-situ CO2 capture has an operating cost about 40% lower than that for the conventional fixed-bed reactor with a separate amine absorption process for CO2 capture. However, the capital cost of the membrane reactor process is about twice that of the conventional process because of the higher cost of the CCDP membrane. Modeling analysis shows that a membrane reactor using a CCDP membrane with higher CO2 permeance (about three times the current value) can deliver the targeted performance for WGS reaction with CO2 capture at a much higher space velocity and lower membrane surface area to catalyst volume ratio, leading to a smaller catalyst amount and/or membrane area and hence significantly reduced membrane reactor capital costs.
- Research Organization:
- Arizona State Univ., Tempe, AZ (United States)
- Sponsoring Organization:
- USDOE Office of Fossil Energy (FE), Clean Coal and Carbon Management
- Contributing Organization:
- University of South Carolina
- DOE Contract Number:
- FE0031634
- OSTI ID:
- 1899858
- Report Number(s):
- DOE-ASU-31634
- Country of Publication:
- United States
- Language:
- English
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