烟气催化脱硫反应器化学反应的数值模拟

The lower outlet SO₂concentration of flue gas and emission standards were achieved mainly through the desulfurization reaction occurred on the surface of the carriers of catalyst in desulfurization reactor.The effects of important structural and operational parameters of the desulfurization reactor on desulfurization percent need to be clearly investigated to predict the desulfurization percent accurately.Based on the finite element software ANSYS,the unsteady flow and catalytic oxidation reaction in the reactor were simulated,the effects of SO₂concentration,empty tower gas velocity and the catalyst packing bed height on the desulfurization percent were investigated by means of a method of reducing effective reaction volume.The regularities of desulfurization percent and outlet concentration of SO₂vs.time were also studied.By comparing the simulated data with the experimental results,the mathematical model of reaction rate for the catalytic desulfurization was corrected.The results showed that the desulfurization percent became lower during heating of the carriers of catalyst,both the desulfurization percent and SO₂outlet concentration of the reactor would decreased with the increasing inlet concentration of SO₂,the effect of the space velocity on the desulfurization percent was great,the operation of the desulfurization system became abnormal at too high or too low space velocity and the desulfurization percent increased with the increasing catalyst packing bed height.Therefore,the reaction rate constant could be corrected based on the changing operation temperature during heating stage of hot flue gas with the good agreement with the industrial data.It is feasible in simulating the unsteady flow and chemical reaction that the unsteady model could be simplified by gradually reducing the total reaction volume of computational domain instead of reducing reaction surface area.The high desulfurization percent could be obtained when the space velocity is in the range from 0.2 to 0.3 m/s.Besides,it is suitable that the catalyst packing bed height ranges from 1 600 to 1 800 mm.The results could provide important basis for engineering design of catalytic desulfurization reactor.