A significant barrier to the commercialization of coal-to-hydrogen technologies is high capital cost. The purity requirements for H(sub 2) fuels are generally met by using a series of unit clean-up operations for residual CO removal, sulfur removal, CO(sub 2) removal and final gas polishing to achieve pure H(sub 2). A substantial reduction in cost can be attained by reducing the number of process operations for H(sub 2) cleanup, and process efficiency can be increased by conducting syngas cleanup at higher temperatures. The objective of this program was to develop the scientific basis for a single high-temperature syngas-cleanup module to produce a pure stream of H(sub 2) from a coal-based system. The approach was to evaluate the feasibility of a 'one box' process that combines a shift reactor with a high-temperature CO(sub 2)-selective membrane to convert CO to CO(sub 2), remove sulfur compounds, and remove CO(sub 2) in a simple, compact, fully integrated system. A system-level design was produced for a shift reactor that incorporates a high-temperature membrane. The membrane performance targets were determined. System level benefits were evaluated for a coal-to-hydrogen system that would incorporate membranes with properties that would meet the performance targets.
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