Numerical Simulation Of Influence Mechanism Of Dissolution Model And Operating Parameters On Flue Gas Desulfurization Reaction Of Powder-Particle Spouted Bed

With the rapid development of modern industry around the world,environmental problems have followed.As one of the most important energy sources in China,coal accounts for a large proportion of the energy consumption structure.However,coal contains a large amount of sulfur,and sulfides such as SO₂ emitted after combustion are liable to cause environmental problems such as acid rain and haze.Reducing SO₂ emissions in exhaust gas has become an environmental problem to be solved.At present,researchers at home and abroad have proposed hundreds of desulfurization technologies of SO₂ emission reduction.Among them,post-combustion desulfurization,that is,flue gas desulfurization,has been widely used because of its many advantages.For the semi-dry flue gas desulfurization technology in post-combustion desulfurization,the semi-dry flue gas desulfurization technology of spouted bed came into being,and the unique flow structure characteristics of the powder-particle spouted bed were studied to make it of great application value in the fields of material drying and chemical reaction.Due to the complexity of the internal flow structure of the spouted bed and the limitation of the existing experimental conditions,the flue gas desulfurization technology is introduced into the spouted bed by numerical simulation,which is expected to obtain the ideal desulfurization effect and provide the theoretical research basis for the practical application of the project.In this paper,based on the experimental spouted bed data of Ma,a numerical simulation is carried out.Based on gas-solid two-phase fluid dynamics,a two-fluid model?TFM?is used to simulate the interaction of gas-solid two-phase in the spouted bed.Through reasonable hypothesis and simplification,the mathematical models of water vapor and desulfurization reaction and the desulfurization reaction dissolution model of the semi-dry flue gas desulfurization system of powder-particle spouted bed are established.By using the"UDF"custom function,the coupling between the gas-solid flow and the chemical reaction in the bed is realized by the correlation formula,and the numerical simulation of the water vapor process and the flue gas desulfurization process is carried out by using the Fluent15.0 calculation software.Through simulation calculation,the distribution of particle volume fraction,water vapor rate,phase temperature and desulfurization reaction product generation rate in the bed is obtained.The results show that water vaporization rate was high in the spouted region and the outside of the annular region because of high gas temperature and gas velocity in the spouted region and large gas-liquid contact area,large gas flow,long water retention time in the outside of the annular region.The production rate of desulfurization reaction products in the annular region is the largest,and the desulfurization products are concentrated in the annular region and gas outlet.Under the same conditions,the simulation value of desulfurization rate is slightly higher than the experimental value,and the simulation error is 0.96%,which indicates that the model used in the simulation is reasonable.On the basis of the above model and calculation results,the influence of the operating parameters such as water content,inlet gas temperature and apparent gas velocity on the particle volume fraction,spouted height,water vapor rate and the desulfurization production rate in the spouted bed is studied by numerical simulation method.The results show that with the water content increases,the water vapor rate decreases,the desulfurization rate is the first to increase and then decreases.with the increase of the inlet gas temperature,the water vapor rate increases and the desulfurization efficiency decreases.When other conditions are the same,the smaller the apparent gas velocity,the lower the spouted height,the narrower the diameter of the spouted region,the smaller the axial and radial velocity and the water vaporization rate,the longer the gas residence time,and the higher the desulfurization efficiency.