Cold Model Experiment And Gasification Zone Fault Simulation Of A New Type Of Chemical Looping Combustion Device

The global warming trend is becoming more and more serious,and CO₂ emission reduction is getting more and more attention.However,human beings are still unable to get rid of the dependence on fossil fuels.Chemical looping combustion technology has attracted extensive attention as a combustion method with its own carbon separation characteristics.Among them,chemical looping combustion is divided into chemical looping combustion of gaseous fuel and solid fuel.Combined with China’s rich coal-poor and low-gas resource reserves,chemical looping combustion of solid fuels such as coal is particularly important.But there are certain problems in combustion or direct feed combustion,which need to be solved by many scholars.In order to avoid the influence of ash generated by solid fuel on the activity of oxygen carrier,a new type of chemical looping combustion device was designed,and a cold model experimental system was built for cold model experiment.The device adopts a three-bed series structure to isolate the solid fuel from the oxygen carrier,simultaneously,the residual heat of the oxygen carrier was used to heat the gas for gasification,thereby avoiding the influence of the solid fuel ash on the oxygen carrier and reducing the additional energy consumption.In the cold model experiment,the effect of the air reactor and the circulating flow rate control valve on the circulation flow rate and the influence of the air reactor and the fuel reactor wind speed on the operating state of the experimental system were analyzed.The results show that the air reactor can be adjusted accurately with the circulating flow rate control valve.The wind velocity of the two reactors were adjusted separately,and the effects on the various parts of the experimental system were analyzed.The wind velocity of the single reactor changed,and the other reactors did not change significantly.The two reactors had good independence.An increase in the air reactor wind velocity causes some of the particles to enter the fuel reactor to increase the overall pressure drop in the fuel reactor;an increase in the fuel reactor wind speed will send some of the particles in the combustion chamber to the gasification chamber.The increase in wind velocity of the air reactor and the fuel reactor promotes the solids circulation rate,but the apparent wind velocity of the air reactor has more effect on the solids circulation rate than the fuel reactor’s.At the same time,the CPFD method was used to numerically simulate the blockage failure phenomenon in the gasification chamber of the gasification chamber encountered in the preliminary experiment,and its influence on the fluidization characteristics of the particles in the bed was analyzed.The simulation results show that partial blockage of the air distribution plate will result in a high concentration area in the bed,which will affect the mixing of particles in the bed.The high concentration zone has a tendency to diffuse to the periphery.The effects of wind speed,bed height and plugging area on the diffusion are analyzed.It is found that as the wind speed increases,the degree of diffusion decreases,and the bed height has less influence on it.The increase in area enhances the degree of diffusion to some extent.