Performance evaluation of porous sodium aluminate sorbent for halide removal process in oxy-fuel IGCC power generation plant

Abstract

Integrated coal gasification combined cycle power generation that adopts oxy-fuel concept has potential to achieve thermal efficiency of 44% at lower heating value besides its CO2 separation ability. Halide control as well as dry gas sulfur removal is inescapable process to the proper operation of the plant. This study investigates performance of dry halide sorbents to establish suitable halide control procedure for the power plant. The most appropriate position of the process is considered to be in the upper stream of the dry sulfur removal process, where the process is able to prevent both corrosion of gas turbine and halogenation of zinc in the desulfurization sorbent. Preproduction sorbents for the dry-gas halide removal process were prepared as pellets containing sodium aluminate as a main ingredient. The sorbents could absorb stoichiometric amount of hydrogen chloride at 450 °C and 0.98 MPa absolute in a simulated coal derived gas environment. The fresh and spent sorbents were examined for dependence of kinetics of halide removal reaction on their pore structures. The results showed that the pore structure comprising of macropore peak at around 5.0 μm and smaller peaks at 1.0 μm or below was suitable to attain affordable kinetics on halide removal and sodium conversion of the sorbent.