【作者】 段振亚；

【导师】 胡金榜；

【作者基本信息】 天津大学 ， 化工过程机械， 2006， 博士

【摘要】 随着经济的快速发展,二氧化硫的排放总量呈现快速增长趋势,消减和控制工业锅炉烟气二氧化硫的排放已成为我国可持续发展的严峻挑战。WX型脱硫装置是天津大学开发的适用于中小型锅炉的高效脱硫除尘一体化装置,本文对其核心元件文丘里洗涤器的脱硫性能进行了试验研究与理论分析,在此基础上设计了适用于中大型锅炉的WX/U型脱硫装置,并通过模拟试验和示范工程考察了该装置的脱硫效果。另外本文还在WX/U型脱硫试验平台上就添加剂对石灰脱硫的强化作用进行了试验研究。首先,就不同参数对文丘里脱硫效率和压力损失的影响进行了试验研究,得到了二氧化硫初始浓度为2000 mg·m-3时,文丘里洗涤器优化操作条件为:氢氧化钠溶液浓度为0.075 mol·l-1,液气比为1.0 l·m-3,喉口气速为40 m·s-1。其次,采用有限反应速率的二阶不可逆反应描述氢氧化钠与二氧化硫的反应过程,在考虑轴向涡流扩散与烟气与液滴相对速度的基础上,得到了描述文丘里内气-液传质的宏观模型。脱硫效率的预测值与实验值吻合良好,三种尺寸的文丘里洗涤器相对误差的算术平均值均小于5%,最大相对误差为-8.07%。再次,根据文丘里洗涤器与旋流分离器的结构特点,设计了结构合理、经济性好的WX/U型脱硫装置。模拟试验表明,优化操作条件下WX/U脱硫效率比单一文丘里洗涤器增加9.6%。20 t·h-1锅炉的WX/U型脱硫装置的运行效果表明,烟气出口的二氧化硫与烟尘浓度均达到了国家标准。在此基础上,还完成了WX/4U脱硫装置应用于2×130 t·h-1锅炉烟气脱硫的工程设计与推广工作。最后,在WX/U模拟试验平台上对脱硫剂进行筛选,研究添加剂对石灰脱硫的强化作用,结果表明增强作用的次序为:硫酸钠>造纸黑液>甲酸>柠檬酸>己二酸>氧化镁>硫酸镁。其中硫酸钠的增强作用最显著,成本也较低,是一个非常有发展前景的添加剂。同时还对硫酸钠强化石灰脱硫时操作条件对脱硫效率的影响进行了研究,并得到了优化的操作条件,氧化钙吸收液浓度为0.8%,液气比为1.0 l·m-3,喉口气速为40 m·s-1,硫酸钠的适宜浓度为0.004～0.006 mol·l-1。更多还原

【Abstract】 With the rapid development of economy in China, the total emission of sulfur dioxide is increasing rapidly in recent years. To control and reduce the emission of sulfur dioxide, therefore, has been became a severe issue for the sustainable development of economy and society in China. WX desulfurization equipments developed independently by Tianjin University is an efficient integrated wet desulfurization and dust removal device suits small-scale and medium-sized boiler. In this paper, experimental and theoretical investigations are conducted on the desulfurization performance of venture scrubber, a key component of WX desulfurization equipments. On this basis, WX/U desulfurization system for large-scale boiler is designed and its performance is verified by experimental and industrial test. In addition, the effect of various additives on the removal efficiency of WX/U desulfurization equipments using lime as absorbent is investigated.Firstly, the effect of operational parameters on the removal efficiency and pressure loss of venturi scrubber is investigated experimentally. And the optimum operational parameters under the condition that the concentration of sulfur dioxide is 2000 mg·m-3 are obtained as follows. Concentration of sodium hydroxide solution is 0.075 mol·l-1, liquid-to-gas ratio is 1.0 l·m-3 and gas velocity in throat is 40 m·s-1.Secondly, a one-dimensional mathematical model is proposed to predict the removal efficiency with second-order chemical reaction in venturi scrubber. In order to describe accurately the mass transfer mechanism occurring in venturi scrubber, the relative velocity of gas and droplets and axial eddy diffusivity are considered. Comparison results between experimental data and those of predicted by present model show that the present model has a good agreement with experiments. Average values of relative error are all less than 5% and the maximum relative error is–8.07%.Thirdly, according to the unique structures of venturi scrubber and cyclone-separator, the WX/U desulfurizaton equipments are developed. And the experimental results show that the removal efficiency of WX/U, under the optimum operational parameters, is higher than that of venturi scrubber by 9.6%. Furthermore, the engineering test of 20 t·h-1 industrial boiler shows that the WX/U desulfuration equipments could meet the requirement of emission standard of air pollutants forthermal power plants in china. On the basis of experimental and engineering test, the promotion and application of WX/4U desulfurization equipments on 2×130 t·h-1 boiler is accomplished.Lastly, the selection of appropriate absorbent is conducted in the experimental set-up of WX/U desulfurization equipments. In addition, to reduce operational cost, the enhancement of various additives on the removal efficiency of WX/4U desulfurization equipments using lime as absorbent is investigated experimentally. The results show that the sequence of enhancement is sodium sulfate>black liquor>formic acid>critic acid>adipic acid>magnesium>magnesium sulfate. Among these additives, sodium sulfate is the most promoting additive for WX/4U desulfurization equipments for its highest enhancement on removal efficiency and the low operation cost. In addition, the optimum operational parameters under the condition that sodium sulfate as additive are obtained as follows. The mass concentration of lime is 0.8%, liquid-to-gas ratio is 1.0 l·m-3, gas velocity in throat is 40 m·s-1 and the effective concentration of sodium sulfate is from 0.004 mol·l-1 to 0.006 mol·l-1.更多还原