Sulfur emission control in fossil fuel gasification plants implies the removal of H2S from the product gas either inside the furnace or in the gas clean-up system. In a fluidized-bed gasifier, in-bed sulfur capture can be accomplished by adding a calcium-based sorbent such as limestone or dolomite to the bed and removing the sulfur from the system with the bottom ash in the form of CaS. This work describes the H2S uptake by a set of physically and chemically different limestones and dolomites under pressurized conditions, typically for those in a pressurized fluidized-bed gasifier (2 MPa, 950 °C). The tests were done with a pressurized thermobalance at two pco2 levels. Thus, the sulfidation of both calcined and uncalcined sorbents could be analyzed. The effect of pH2s was also investigated for uncalcined limestones and half-calcined dolomites. The results are presented as conversion of CaCO3 or CaO to CaS vs time plots. The results are also compared with the sulfur capture performance of the same sorbents under pressurized combustion conditions.
- H2S, sulfur capture, sorbents, pressurized gasification