Research On The Cyclic Reaction Performance Of Calcium Sulfate-based Composite Oxygen Carrier

Chemical looping combustion(CLC)is a new combustion technology.It is different from the traditional combustion.In the chemical looping combustion system,the fuels needn't to react with the air directly instead of useing oxygen carrier.It could not only avoid NOX emission,obtained and captured high pure CO2,but also can achieve a very high efficient use of energy.In a word,chemical looping combustion in the field of CO2 reduction has a high research value and a favorable application prospects.In the CLC system,oxygen carrier's performance is crucial,Ca SO4 is considered as a popential substitute for fautre industrial applications,because of its rich reserverse,low prices,high oxygen capacity.In the chemical looping combustion process,Ca SO4 oxygen carrier suffers from the problems of sulfur release in the form of gas sulfide and will affect its life,so control the release of gaseous sulfides is the key to the study of Ca SO4 oxygen carriers.In this paper,both Ca SO4/Cu O and Ca SO4/Ca O oxygen carriers are prepared by mechanical mixing method.The mass of oxygen carrier,reaction temperature reduction,and different Cu O/Ca SO4 molar ratio were investigated.at the same time,the cyclic reactions were studied when the reduction temperature was 900? and the oxygen concentration were 5% and 10%.The cyclic performances of Ca SO4/Ca O composite oxygen carrier were studied.The effects of reaction conditions on CO2 formation and sulfide release were discussed.The flue gas analyzer and gas chromatograph were used to analyze the composition and concentration of the reaction tail gas.The combustion cycle performance of the composite oxygen carrier in CO atmosphere was studied.The solid content and solid morphology of the solid residue were characterized by XRD and SEM-EDS.(1)The results show that the addition of Cu O not only inhibit the release of sulfur gas,but improve the activity of Ca SO4 carrier.(2)In the experimental study on the cyclic reaction of Cu O/Ca SO4 combined oxygen carrier,when the reduction temperature is 900°C,the fuel was 5% CO,and the oxidation gas was 5% O2,with the increase of oxidation reaction temperature.The cyclic performance and FR-SO2 release of oxygen carriers gradually decreased,and the amount of AR-SO2 released gradually increased.(3)When the oxidition atmosphere was O2 which concentration is 10%,with the increase of the oxidation temperature,the cycling reaction performance of the Cu O/Ca SO4 composite oxygen carrier decreases,and the release of FR-SO2 gradually increases,AR-SO2 release also increased.(4)The addition of Ca O can improve the activiy of oxygen carrier.With and without the addition of Ca O additive,the CO2 yield decreased slightly after the first cycle both Ca SO4 oxygen carrier and Ca SO4-Ca O combined oxygen carrier;in the subsequent cycle reaction,the CO2 yield can be maintained at a high level with the Ca O addition,and inhibit the release of COS-FR and SO2-AR,but the release of SO2-FR increased.(5)The increasment of Ca O/Ca SO4 molar ratio can promise a high CO2 generating efficiency.With the use of Ca O additive,the E-factor of SO2 decreases,but when Ca O/Ca SO4 ratio raises from 1 to 2,there was no obvious change in SO2 E-factor.