Natural gas fired power plants with CO2-capture-process integration for high fuel-to-electricity conversion efficiency

A concept for capturing and sequenstering CO 2 from a natural gas fired combined cycle power plant is presented. The present approach is to decarbonise the fuel prior to combustion by reforming natural gas, producing a hydrogen-rich fuel. The reforming process consists of an air-blown pressurised auto-thermal reformer that produces a gas containing H 2 , CO and a small fraction of CH 4 as combustible components. The gas is then led through a water gas shift reactor, where the equilibrium of CO and H 2 O is shifted towards CO 2 and H 2 . The CO 2 is then captured from the resulting gas by chemical absorption. The gas turbine of this system is then fed with a fuel gas containing approximately 50% H 2 . In order to achieve acceptable level of fuel-to-electricity conversion efficiecy, this kind of process is attractive because of the possibility of process integration between the combined cycle and the reforming process. A comparison is made between a “standard” combined cycle and the current process with CO 2 -removal. This study also comprise an investigation of using a lower pressure level in the reforming section than in the gas turbine combustor and the impact of reduced steam/carbon ratio in the main reformer.