Key Words:Gas generators;Coal combustion - Fuels - Gas emissions - Gasification - Oxygen - Sulfur dioxide - Synthesis gas - Thermoanalysis - Thermodynamic properties;Chemical looping - Chemical-looping combustion - Effect of temperature - Gasification process - Mass and heat balances - Oxygen Carrier - Syn-gas generation - Thermo dynamic analysis

Abstract:Chemical-looping gasification (CLG) is a novel process for syngas generation from solid fuels, sharing the same basic principles as chemical-looping combustion (CLC). It also uses oxygen carriers (mainly metal oxide and calcium sulfate) to transfer heat and oxygen to the fuel. In this paper, the primary investigation into the CLG process with CaSO<inf>4</inf> as oxygen carrier was carried out by thermodynamic analysis and experiments in the tube reactor. Sulfur-contained gas emission was mainly H<inf>2</inf>S rather than SO<inf>2</inf> in the CLG process, showing some different features from the CLC. The mass and heat balance of CLG processes were calculated thermodynamically to determinate the auto-thermal operating conditions with different CaSO<inf>4</inf>/C and steam/C molar ratios. It was found that the CaSO<inf>4</inf>/C molar ratio should be higher than 0.2 to reach auto-thermal balance. The effect of temperature on the reactions between oxygen carrier and coal was investigated based on Gibbs free energy minimum method and experimental results. It indicated that high temperature favored the CLG process in the fuel reactor and part of syngas was consumed to compensate for auto-thermal system. &copy; 2013 Chemical Industry and Engineering Society of China (CIESC) and Chemical Industry Press (CIP).

Volume:21

Issue:2

Translation or Not:no