【作者】 程峰；

【导师】 骆仲泱； 倪明江； 岑可法；

【作者基本信息】 浙江大学 ， 工程热物理， 2005， 博士

【摘要】 随着经济和社会的发展,燃煤锅炉排放的二氧化硫严重地污染了我们赖以生存的环境。石灰石-石膏湿法烟气脱硫技术具有工艺成熟、脱硫剂来源广泛、价格低廉、脱硫效率高、副产品可以回收利用等优点,获得了广泛的应用。但是湿法烟气脱硫系统的投资和运行成本较高。以提高脱硫效率、降低投资和运行成本为目的,本文提出了液柱冲击塔,对这种湿法脱硫装置的性能进行了研究。 本文对液柱冲击塔的阻力特性和脱硫特性进行了试验研究和分析。试验研究了喷液量、塔内风速,结构等因素对阻力特性的影响,以及喷液量、塔内风速、循环水池pH值、SO₂入口浓度、烟气入口温度、结构等因素对脱硫效率的影响,还研究了添加剂甲酸、甲酸钠和己二酸的脱硫添加剂的作用。根据试验研究结果给出了液柱冲击塔的运行工况设计。 液柱冲击塔内,液柱冲击雾化形成的液滴的粒径分布、液滴速度等流场特性对二氧化硫的吸收有着重要的影响。本文利用PIV方法对液柱塔内雾化液滴的粒径分布和运动状态进行了试验研究,给出了浆液流量、烟气流速、喷嘴与挡板间距、挡板类型等因素对雾化液滴粒径分布和运动特性的影响。试验研究的结果表明:烟气流速一定时,浆液流量越大,浆液液滴的平均粒径也越大;浆液流量一定时,液滴平均粒径随烟气流速增大而减小;在相同的烟气流速和浆液流量下,喷嘴与挡板间距越小,雾化效果越好;雾化后的浆液液滴粒径分布符合Rosin-Rammler分布。 以多相流体力学、化学反应动力学、湍流扩散和传质理论为基础,对液柱冲击塔建立二氧化硫吸收模型,考虑了喷淋密度、烟气流速、液滴粒径变化和分布等参数对塔内流场分布和SO₂吸收的影响,运用CFD对塔内的流场和二氧化硫的吸收过程进行了数值模拟,并根据数值模拟的结果对液柱塔入口的几何形状进行了相应的优化。数值模拟和试验结果吻合较好,对液柱冲击塔的工业应用具有一定的指导意义。 本文还对适用于中小型电站锅炉的湍流式简易湿法脱硫除尘装置的阻力特性和脱硫特性进行了试验研究和工程应用,分析了简易湿法脱硫除尘装置烟气带水的原因,通过试验研究优化旋流板设计,提高除湿效率,解决了烟气带水问题。更多还原

【Abstract】 With the development of economy, the environment we live in is badly polluted by SO₂ from coal-fired boilers. Limestone-gypsum wet flue gas desulfurization technology is being widely applied all over the world because of its advantages: high desulfurization efficiency, widespread and cheap absorbent, retrievable and available byproduct. But the capital cost and operation cost are too expensive to be accepted by our consumer in China. In the thesis, impinge stream scrubber are carried out in order to decrease its capital cost and operation cost.The resistance and desulfurization characteristic of impinge stream scrubber are studied. The effects of slurry flux density and flue gas velocity on the resistance in the scrubbers and the effects of slurry flux density, flue gas velocity, circulating tank pH, SO₂ inlet concentration, and flue gas inlet temperature on desulfurization in the scrubbers are studied. The effects of additives （formic acid, sodium formate and adipic acid） on desulfurization in the scrubbers are also studied. The characteristics of the scrubbers are found. Optimum operation parameters are obtained on the basis of experimental investigation results.The flow field characteristic in impinge stream scrubber such as the diameter and velocity distribution of atomized slurry droplets has great effect on SO₂ absorption. With PIV technology, the diameter distribution and motion state of droplets is investigated. The effects of slurry flux, flue gas velocity, the distance between damper and nozzles and damper type are studied. As can be seen from the experimental investigation results, the mean diameter of slurry droplets increase with a greater slurry flux when the flue gas velocity is indefinite; but when the slurry flux is infinite, it will decrease when the flue gas velocity increases. The atomization effect is better with a less distance between damper and nozzles. And the droplets diameter distribution is Rosin-Rammler.On the basis of multiphase fluid dynamics, chemical reaction kinetics, turbulent diffusion and mass transfer theory, the SO₂ absorption model in impinge stream scrubber is set up. The effect s of slurry flux density, flue gas velocity, droplets diameter change and distribution on flow field distribution and SO2 absorption are taken into consideration. The flow field and SO₂ absorption in 1 impinge stream scrubber has been simulated by CFD method. In order to improve the distribution of flow field, the geometry of tower entrance is optimized. The calculated results agreed well with the test results. The results may give some directions on the design and operation of impinge stream scrubber.The resistance and desulfurization characteristic of turbulent ball scrubber which is fit for medium and small sized station boiler is also studied on pilot-scale and industry application. The reason of flue gas carrying water is analyzed and solved by the optimum design of rotating dehumidification plate to improve dehumidification efficiency.更多还原