Abstract： Two Canadian limestones with different properties were tested to determine the effect of SO2 during the carbonation of sorbent on the CO2 capture performance in Ca- looping. When the reaction gas is mixed w...Abstract： Two Canadian limestones with different properties were tested to determine the effect of SO2 during the carbonation of sorbent on the CO2 capture performance in Ca- looping. When the reaction gas is mixed with SO2, the carbonation ratio of the sorbent is always lower than that without SO2 for each cycle under the same conditions, and the sulfation ratio increases almost linearly with the increase in the cycle times. At 650 ℃, there is little difference in the carbonation ratio of the sorbent during the first four cycles for the two carbonation time, 5 and 10 rain at 0. 18% SO2. The indirect sulfation reaction that occurs simultaneously with the carbonation of CaO is responsible for the degradation of the sorbent for CO2 capture, and the carbonation duration is not the main factor that affects the ability of the sorbent. 680℃ is the best carbonation temperature among the three tested temperatures and the highest carbonation ratio can be obtained. Also, the sulfation ratio is the highest. The probable cause is the different effects of temperature on the carbonation rate and sulfation rate. A higher SO2 concentration will decrease the carbonation ratio clearly, but the decrease in the carbonation capability of the sorbent is not proportional to the increase of the SO2 concentration in flue gases.展开更多
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 ox...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 CaSO4 as oxygen carrier was carried out by thermodynamic analysis and experiments in the tube reactor. Sulfur-contained gas emission was mainly H2S rather than SO2 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 CaSO4/C and steam/C molar ratios. It was found that the CaSO4/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 ex- perimental 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.展开更多
基金The National Natural Science Foundation of China(No.51276064)the Natural Science Foundation of Beijing City(No.3132028)
文摘Abstract： Two Canadian limestones with different properties were tested to determine the effect of SO2 during the carbonation of sorbent on the CO2 capture performance in Ca- looping. When the reaction gas is mixed with SO2, the carbonation ratio of the sorbent is always lower than that without SO2 for each cycle under the same conditions, and the sulfation ratio increases almost linearly with the increase in the cycle times. At 650 ℃, there is little difference in the carbonation ratio of the sorbent during the first four cycles for the two carbonation time, 5 and 10 rain at 0. 18% SO2. The indirect sulfation reaction that occurs simultaneously with the carbonation of CaO is responsible for the degradation of the sorbent for CO2 capture, and the carbonation duration is not the main factor that affects the ability of the sorbent. 680℃ is the best carbonation temperature among the three tested temperatures and the highest carbonation ratio can be obtained. Also, the sulfation ratio is the highest. The probable cause is the different effects of temperature on the carbonation rate and sulfation rate. A higher SO2 concentration will decrease the carbonation ratio clearly, but the decrease in the carbonation capability of the sorbent is not proportional to the increase of the SO2 concentration in flue gases.
基金Supported by the National~ Natural Science Foundation of China （20876079）, the Natural Science Funds for Distinguished Young Scholar in Shandong Province （JQ200904）, and Shandong Province Key Technologies Research and Development Program of China （2008GG 10006010, 2009GG 10007001）.
文摘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 CaSO4 as oxygen carrier was carried out by thermodynamic analysis and experiments in the tube reactor. Sulfur-contained gas emission was mainly H2S rather than SO2 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 CaSO4/C and steam/C molar ratios. It was found that the CaSO4/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 ex- perimental 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.
