Designing for hydrogen, electricity, and CO2 recovery from a Shell gasificationbased system

摘要

The U.S. Department of Energy (DOE) is investigating CO2 recovery from fossil-fuel cycles as a greenhouse gas mitigation strategy. Recognizing this, we compared two integrated gasification combined-cycle (IGCC) plant designs based on the Shell entrained-flow gasifier. One option, called the 'co-product case,' uses high-sulfur Illinois no. 6 coal to produce electricity and hydrogen (H2) as energy carriers. At the same time, 90% of the carbon dioxide (CO2) is recovered for disposal in geological storage or for use, such as in enhanced-oil recovery (EOR). The second option called the 'base case,' is a conventional IGCC power plant releasing CO2 by combustion of the synthesis gas in a gas turbine. Process design has been aided by the use of the ASPEN-Plus (trademark) simulation for critical design areas. Special attention is paid to the transport issues for the CO2 product, because transportation technology is a determinant of product specifications, which affect plant design. Separating and purifying the H2 for fuel cell use should yield an impressive gain in overall process efficiency, offsetting the losses in efficiency from recover and compression of CO2 to supercritical conditions.