ABSTRACT
A new pre-combustion natural gas fired power plant concept with an Oxygen Transfer Membrane (OTM) reactor and a H₂ fired combined cycle has been developed. The OTM reactor consists of 3 channels: one steam reformer channel that produces synthesis gas, one combustion channel that supplies heat to the steam reforming channel, and an air channel with the OTM, that feeds the combustion channel with pure oxygen through the OTM. A PSA separates a shifted synthesis gas into a hydrogen fuel stream and a purge gas, which is fed to the combustion channel in the OTM reactor. The hydrogen fuel is diluted with nitrogen in a catalytic pre-burner by reacting partly with the oxygen lean air from the air channel. After the pre-burner, the hydrogen is fed to a H₂ fired combined cycle. The net energy efficiency of the concept is 48%, which is relatively high compared with pre-combustion concepts presented in prior art. Especially the 3-channel OTM reactor and the PSA contribute to this high efficiency. However, this high efficiency is dependent on a high level of heat integration. The concept has a potential for improvements, and an efficiency of 50% can be achieved by increasing the PSA purge gas pressure and implementing an even higher degree of heat integration. The development of the OTM reactor is still in its conceptual phase. A preliminary cost estimate of the concept with a two H₂ fired combined cycle trains producing 858 MW net electricity indicates a electricity cost of 44.5 €/MWh. However, these numbers have a relatively high uncertainty, due to the immaturity of the OTM reactor and, to some extent, the H₂ fired combined cycle.