Abstract
A technology of carbon dioxide capture and storage (CCS) is the one of global warming countermeasure. As an oxidizer in advanced integrated coal gasification combined cycle (A-IGCC), the utilization of mixture gas including carbon dioxide (CO_2) and oxygen (O_2) is discussed. In the present study, a coal gasifier with two-stage entrained bed was numerically simulated to investigate the adaption of O_2/CO_2-blown system in gasifier. Thermal loss on the gasifier furnace wall was considered in this simulation. Because the reaction of coal gasification was promoted by CO_2, we can operate the gasifier system for low oxygen ratio compared with the conventional system. By the control of the reactor/total coal ratio, we can easily operate the gasifier system. At the O_2/CO_2-blown system, high level gas heating value was obtained and the operation range with safety combustion became wide. We can expect the enhancement of thermal efficiency of power generation and the reduction of reductor length for the operation of low oxygen ratio.
