Development of high-efficiency oxy-fuel IGCC system

CCS is a method of reducing CO₂ emission but it deteriorates the efficiency of power stations. It is important to ensure high efficiency so that limited fossil fuel resources can be used effectively. We are carrying out a project to develop innovative gasification technology for CCS that maintains a high efficiency of more than 40% at HHV. In this project we gasify coal with a mixture of O₂ and recirculated CO₂ exhaust gas, similarly to in oxy-fuel combustion. Because CO₂ concentration of the exhaust gas is sufficiently high, a CO₂ separation unit is not required and the system can be simplified. Moreover as CO₂ gas acts as a gasifying agent for coal, the high CO₂ concentration improves the performance of the gasifier. CRIEPI confirmed this effect using a pressurized drop tube furnace (PDTF), and on pressurized entrained flow gasifier with a capacity of 3 tons per day (3TPD). Fundamental experiments on a hot gas clean-up system have been carried out to develop countermeasures for carbon deposition in high-CO-concentration syngas. In this paper, we introduce the latest status of this project executed by CRIEPI by referring several papers previously published by CRIEPI.