Integration of H2-Separating Membrane Technology in Gas Turbine Processes for CO2 Sequestration

Publisher Summary The chapter describes the possibility of capturing CO2 in natural gas fired power cycles through the integration of a H2-separating membrane in a component for steam reforming of natural gas, a so-called membrane reactor. Two types of membranes are investigated: Pd membranes, which could allow for zero-emission power cycles, and microporous membranes, the use of which in the present work means that 20% of the generated CO2 is emitted to the atmosphere. to reduce the CO2 emission from natural-gas based power-generation plants, three different main types of concepts have emerged as the most promising: (1) separation of CO2 from exhaust gas coming from a standard gas-turbine (GT) combined cycle (CC), using chemical absorption by amine solutions; (2) oxyfuel CC with a close-to-stoichiometric combustion using as oxidizing agent with CO2 and water vapor as the combustion products; and (3) fuel decarbonization in which the carbon of the natural gas (NG) is removed prior to combustion and the fuel heating value is transferred to hydrogen. Three non-optimized power cycles with a membrane reactor are studied, the best of which (a combined cycle with a directly fired gas turbine) has a thermal efficiency of only 41.6%. Through refined process layout and systematic process optimization, it should be possible to design a process with significantly higher thermal efficiency.