【作者】 傅旭明；

【导师】 刘吉普； 叶恒棣；

【作者基本信息】 湘潭大学 ， 化工过程机械， 2011， 硕士

【摘要】 我国钢铁冶炼以“烧结（球团）和焦化—高炉—转炉”的流程为主。据统计,烧结工艺所产生的SO₂的排放量达到了钢铁行业总排放量的70%以上,并呈上升趋势。烧结机脱硫已经成为我国节能减排工作的重点。长期以来,焦化工序产生的废氨水的处理难度极大,将焦化废氨水用来处理烧结机产生的SO₂既节约了脱硫成本,又解决了废氨水的处理问题,产生的硫酸铵是一种资源,符合可持续发展的要求。本文以烧结机排放的烟气中SO₂为研究对象,以氨法脱硫为研究手段,首先建立了脱硫塔内SO₂的吸收模型和气液运动模型,运用FLUENT软件模拟了脱硫塔内的流场和SO₂浓度场等,发现:喷淋对脱硫塔浆液池液面以上的烟气流场影响很小;无喷淋时,烟气在脱硫塔喷淋段的流场分布较均匀,增加喷淋后,喷淋段流场分布不均。此外,分析了脱硫塔内SO₂浓度场,发现SO₂浓度变化明显的地方是喷嘴形成的液膜的地方,说明喷淋液膜没有破碎之前脱硫效果最好,SO₂的脱除是靠喷嘴附近的浆液吸收完成的,SO₂浓度场的模拟为脱硫塔的优化设计提供了有利手段。本文从实验的角度考察了各关键因素（pH、液气比、初始SO₂浓度、烟气温度、浆液浓度）对脱硫效率的影响,发现:pH在4.0～4.5时对脱硫率影响不大,在4.5～7.0时对脱硫率影响比较明显;液气比与脱硫率在一定范围内线性关联较好;初始SO₂浓度越高,脱硫率越低;一定范围内的温度变化对脱硫率影响不大;吸收浆液浓度越高,脱硫率越低。本文模拟了各关键因素（pH、液气比、初始SO₂浓度、烟气温度、浆液浓度）对脱硫率的影响,并将模拟值和实验值进行了比较,发现:低pH条件下,模拟值和实验值对脱硫效率的影响趋势不符,高pH在一定程度上相符,但存在较大的偏差;不同液气比脱硫效率的模拟值和实验值之间存在10%以上的偏差,液气比为10L/m³时,模拟曲线出现转折点,实验曲线没有转折点;初始SO₂为3000 mg/m³时,在液气比小于12L/m³曲线段SO₂脱除率模拟值与实验值变化趋势相关性比较好,液气比大于12L/m³时,变化趋势不相符。初始SO₂为1000 mg/m³时,在液气比大于10L/m³曲线段SO₂脱除率模拟值与实验值变化趋势相关性比较好,液气比小于10L/m³时,变化趋势不相符。3000 mg/m³和1000 mg/m³初始SO₂浓度的脱硫率模拟值和实验值偏差较大;温度越高模拟的脱硫率越高,与实验结论不符;模拟的浓度为15%的浆液脱硫效率最高,实验结果6%和15%的浆液脱硫效率相当。在一定范围内,低浓度浆液的脱硫效率高,模拟结果和实验结果之间有一定的偏差。更多还原

【Abstract】 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.更多还原