Study On Formation And Inhibition Of Fe Based Oxygen Carrying Volumetric Carbon In Coal Chemical Looping Combustion

Chemical looping combustion is an important carbon capture method.The cycle stability of the oxygen carrier and the inhibition of carbon deposits are important issues that need to be further broken through in the chemical looping combustion method.This article focuses on the combustion ratio and cycle performance of the oxygen carrier to fuel.As well as the reaction atmosphere,the changes in the morphology and structural components of Fe₂O₃/Al₂O₃ oxygen carriers after reacting with different coals were analyzed,and the influence of different conditions on the formation of polycyclic aromatic hydrocarbons in the reaction,as well as the reasons for the formation of oxygen-carrying volumetric carbon,were studied.The relationship between combustion reaction conditions.To find feasible carbon deposition inhibition conditions and methods to solve the carbon deposition problem on the oxygen carrier,improve the reactivity of the oxygen carrier to extend its life,and increase the carbon dioxide capture rate.First,the influence of combustion ratio on the generation of oxygen-carrying volumetric carbon is analyzed.When the combustion ratio is 40:1,the proportion of bottom-ring aromatics is the largest,the proportion of high-ring aromatics is the smallest,and the amount of carbon deposits is also the smallest.It shows that in a gas-free atmosphere,increasing the combustion ratio is beneficial to suppress carbon deposits,and subsequent experiments are carried out on the basis of a 40:1 combustion ratio.Secondly,the cycle performance of the oxygen carrier and the generation of carbon deposits are analyzed.The proportion of PAHs produced at T1 is the largest,and the proportion of PAHs produced at T10 is the least.The difference between the amount of production and the amount of production at T15 is very small.The changes in carbon are consistent and vary greatly between T1-T3.After the oxygen carrier cycled to deoxygenate and absorb oxygen,in the XRD pattern analysis of T10 and T15times,the peak intensity and peak width of Fe₂O₃did not change significantly.It shows that the oxygen carrier is activated at the beginning of the cycle reaction,and the oxygen carrier is fully activated when the cycle is 3 times,and the reaction activity increases.After 15 redox reactions,its reduction degree and purity are still relatively good,and the performance is stable.Cycle at high temperature can maintain good phase and reducibility.Finally,the effect of water vapor and carbon dioxide on the suppression of carbon deposits is analyzed.In a 40%CO₂ combustion atmosphere,the production of PAHs is the least.Compared with the conditions without CO₂,both PAHs and carbon deposits are reduced.In a H₂O atmosphere with a concentration ratio of 100%,the amount of PAHs generated is the least.Compared with the condition without H₂O,only the carbon coke-type carbon deposits are reduced.In the mixed atmosphere of water vapor and carbon dioxide,the carbon deposits in bituminous coal and anthracite are reduced,and the reduction in carbon deposits of anthracite is more than that of bituminous coal;and when the combustion ratio is 30:1,the amount of carbon deposits generated is the least.The results show that a combustion atmosphere with a 40%CO₂ concentration ratio is the best reaction condition for inhibiting carbon deposition.The water vapor atmosphere can reduce the amount of polycyclic aromatic hydrocarbons and carbon coke type carbon deposits at a lower concentration ratio of 0-20%.The mixed atmosphere of water vapor and carbon dioxide can effectively inhibit carbon deposition,and the effect is best when the combustion ratio is 30:1.