关键词: 化学链燃烧, CaSO4竞争还原反应, Boudouard反应, 积碳

Abstract: For the application of CaSO4 oxygen carrier in chemical looping combustion (CLC)，the thermodynamic of Boudouard reaction during the process of CaSO4 reduction with CO were investigated at 500—1200 ℃，at different CO concentrations (0.5%—99.0%)，CO2 concentrations (0—70%) and SO2 concentrations (0—10%). And the control method of the Boudouard reaction for less carbon deposition on oxygen carrier was discussed. The expression forms of the equilibrium constants of CaSO4 reductions and Boudouard reaction differed，and therefore，direct comparisons on the extents of the chemical reactions cannot be done. The extents of the chemical reactions of the competitive reductions of CaSO4 and the side reaction of the Boudouard reaction were analyzed based on the CO equilibrium conversions. For the suitable temperature of fuel reactor in CLC (850—1050 ℃)，higher CO concentrations favor the Boudouard reaction，while the SO2 concentrations had no effects on the extent of the Boudouard reaction. The Boudouard reaction was suppressed at higher reaction temperatures and higher CO2 concentrations. Furthermore，when the CO concentration was at 95% and the CO2 concentration in the gas reactant was above 3.7%，the Boudouard reaction was not able to be initiated.

Key words: chemical looping combustion, competitive reduction of CaSO4, Boudouard reaction, carbon deposition