A Preliminary Study On The Reaction Performance Of Iron-based Composite Oxygen Carriers

Chemical looping combustion?CLC?is a new combustion technology.It is different from the traditional combustion.In the CLC system,the fuels needn't to react with the air directly instead of using oxygen carrier.It could not only avoid NO_X 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 CO₂reduction has a high research value and a favorable application prospects.Oxygen Carrier is the important factor to Chemical Looping Combustion.The metal oxide oxygen carrier itself has high reaction performance and can maintain structural integrity and stable reaction performance during multiple reduction oxidation processes.Therefore,it has attracted considerable attention,extensive research and application.Fe-based oxygen carriers have relatively high activity,usually in the form of FeO,Fe₂O₃,Fe₃O₄.In this paper,Fe₂O₃ was used as the oxygen carrier,Al₂O₃ and MgO were selected as the support carriers,and a series of Fe₂O₃/Al₂O₃,Fe₂O₃/MgO oxygen carriers were prepared by impregnation method,and on this basis,the carrier is loaded with 10%by mass of CuO,and its reduction performance is studied.The development of sulfur-tolerant oxygen carriers is also an important research content and direction of chemical chain combustion.In this paper,the predominant region of CuO and Fe₂O₃ as sulfur carriers in the reaction with sulfur was studied by using Factsage software.The formation of products during the reaction of three oxygen carriers and sulfur gas at different temperatures was investigated.?1?The results shows the increase of Fe₂O₃ mass content has an important influence on the reduction performance of Fe₂O₃/Al₂O₃ and Fe₂O₃/MgO oxygen carriers.The reduction performance of Fe₂O₃/MgO at each Fe₂O₃ content is higher than that of Fe₂O₃/Al₂O₃ at the same Fe₂O₃ content.At the same time,the hydrogen consumption of Fe₂O₃/MgO oxygen carriers per unit mass decreases with the increase of Fe₂O₃ content.When the mass ratio of Fe₂O₃ to MgO is 1.5:8.5,the hydrogen consumption per unit mass of oxygen carrier reaches the maximum.?2?Through CO thermogravimetric experiments,it was found that with the increase of temperature,the maximum weight loss rate of the oxygen carrier Fe1Mg9 at900?was 3.65%,and the maximum weight loss rate was 0.24%min^-1,and the reaction temperature increased to At 950?,the maximum weight loss rate of Fe1Mg9decreased to 3.65%.?3?Compared with the oxygen carrier of Fe₂O₃/Al₂O₃,the reduction ability of Fe₂O₃-CuO/Al₂O₃ was improved after loading CuO,however,the Fe₂O₃-CuO/MgO carrier has a reduced ability to reduce H₂ after loading CuO.Fe₂O₃-CuO/MgO with the same Fe₂O₃ content has higher reduction reaction ability than Fe₂O₃-CuO/Al₂O₃.?4?The reaction of Fe₂O₃ with sulfur is sorted according to the difficulty of the reaction,respectively:the reaction of forming Fe₃O₄,FeS,FeS₂,FeAl₂O₃,FeO and Fe₂?SO₄?₃.The higher sulfur equilibrium concentration is beneficial to the formation of FeS₂ and FeS,while the lower sulfur equilibrium concentration is beneficial to the formation of Fe₃O₄,FeO and Fe.?5?With the increase of temperature,the stable regions of CuO and Cu₂O are gradually enlarged,and the stable region of Cu during the transition from Cu₂O to Cu₂S is gradually expand,and the stable region of CuS is gradually reduced.