Experimental And Numerical Simulation Investigation On Ammonia Desulphurization Of Sintering Machine Exhaust

The process of sintering and coking, to blast furnace, then to converter is the main technology practiced in iron and steel smelting in China. According to statistics, the sintering process results SO₂ emissions to total emissions of the steel industry for over 70% and rising. Desulphurization of sintering machine has become the focus of our energy reduction. For a long time, coking processes produce the waste ammonia can be difficulty deal with, which will greatly used to handle sintering machine coking produced SO₂ both saved the desulfurization cost, and solves the processing problem ammonia waste produced a resource and ammonium sulfate with the requirement of sustainable development.In this paper, an absorption model of SO₂ in the tower and a motion model of liquid and gas were established. The flow distribution and the concentration distribution of SO₂ were simulated using the FLUENT software and the results showed that spraying hardly influenced the gas flow distribution above the liquid surface, while when the spraying stopped the gas distribution was uniform in the spray section of the desulfurization tower. Besides, by the analysis of the SO₂ concentration distribution, we found that where the nozzle formed the liquid film was the point where the concentration of SO₂ had a sharp change, which indicated that, best desulfurization was achieved before the spray liquid film broke and. So, in a word, the removal of SO₂ was accomplished by the slurry around the nozzle and the model of SO₂ concentration distribution is a good method to optimize the desulfurization tower.In this paper, the discharged SO₂ from the sintering machine as a target was treated through ammonia desulfurization process, the key factors such as pH, the ratio of liquid to gas, the initial SO₂ concentration gas temperature, and slurry concentration, were all investigated in experiments. Moreover, the slurry after desulfurization was tested and we found that low pH value under 4.5 had no obvious effect on the desulfurization efficiency, yet high pH value showed the opposite. The ratio of liquid to gas correlated to the efficiency within certain limits. The higher was the initial SO₂ concentration, the poorer was the desulfurization performance. Within a certain range, temperature had no significant influence upon the performance. The higher concentrations of the slurry lead to the lower efficiencies.The simulation of the key factors affecting the desulfurization efficiency was compared to the experiment values. Results showed that, under low pH conditions, simulated and experimental values did not match, and under the high pH, two values corresponded to each other to a certain extent, but there was a large deviation. There was a more than 10% deviation between different the simulated and experimental values under different liquid-gas ratio. When the ratio was 10L/m³, the simulation curve had a turning point while there was none in the experimental curve. Under the initial SO₂ of 3000 mg/m³ and the liquid-gas ratio less than 12L/m³, SO₂ removal efficiency curve segment simulated trends associated better with the experimental, but when the liquid-gas ratio was greater than 12L/m³, trends did not match. With the initial SO₂ of 1000 mg/m³, the liquid-gas ratio was greater than 10L/m³ SO₂ removal efficiency curve segment between the simulated and experimental data showed better correlation between trends, yet with liquid gas ratio less than 10L/m³, the trends did not match. 3000 mg/m³ and 1000 mg/m³ SO₂ concentration in the initial desulfurization rate of deviation of simulated and experimental values was relatively large; the higher the temperature the higher the desulfurization rate of the simulation, but experimental results did not match; simulated slurry concentration of 15% accorded to desulfurization efficiency maximum, while the experimental results showed that slurry concentration of 6% and 15% had same efficiency. Within a certain range, low concentration slurries had better desulfurization efficiency, but there was a big difference between simulation results and experimental results.