Integrated characteristics and performance of zero emission coal system

Abstract

Before the commercialization of zero emission coal (ZEC), some technical hurdles must be settled and the performance of the whole system needs to be studied. The main technical hurdles of ZEC system are analyzed and some solutions are presented in this paper. A detailed ZEC system is setup and its characteristics are studied. High temperature solid oxide fuel cell (SOFC) is used to produce electricity and served as the heat source for the decarbonater. ZnO and NaHCO3 are proposed to deeply eliminate H2S and HCl. H2 recycle ratio should be kept at 0.75 for the high conversion ratio of carbon in the gasifier and the high system efficiency. Calcium to carbon mole ratio (CTCR) should be kept around 0.6 to reach high CO2 sequestration rate and acceptable economic penalty. Fuel utilization factor (Uf) of SOFC should be kept around 0.55 so as to supply enough heat to the decarbonater, and steam to carbon ratio (STCR) for the reformers in the system should be kept around 2.0. With these optimized parameters, the total efficiency of the system of 69.1% and the CO2 sequestration ratio of 87% can be reached.