A quantitative comparison of gas turbine cycles with CO2 capture

Nine different concepts for natural gas fired power plants with CO2 capture have been investigated, and a comparison is made based on net plant efficiency and emission of CO2. The cycles are one post-combustion, six oxy-fuel and two pre-combustion capture concepts. A 400MW combined cycle plant is applied as a reference case. A common basis for the comparison of all concepts is defined and employed in heat- and mass-balance simulations of the various concepts. As gas turbine cooling impacts the net plant efficiency at high turbine inlet temperatures, a simplified turbine cooling model has been applied in the simulations. It is found that the concepts, in which novel technology (the hydrogen membrane separation reformer—-MSR-H2, the advanzed zero emission power plant—AZEP, the solid oxide fuel cell combined with a gas turbine—SOFC+GT and the chemical looping combustion—CLC concepts) is employed, exhibit the best performance with respect to both efficiency and in most cases also CO2 capture (capture rates close to 100%). Post-combustion capture and pre-combustion capture with auto-thermal reforming, which are based on more mature technology, show a lower efficiency and a capture rate of typically 90%. The SOFC+GT concept exhibits the best cycle performance and even better than a standard CC plant, however, any realization of a SOFC-GT 400MW plant has a very distant future perspective. In order to conduct a complete assessment of these diverse concepts, other criteria for comparison such as e.g. technology level and costs should also be considered. This is not, however, included in the present work.