火电厂脱硫废水蒸发工艺及对烟气除尘脱硫的影响研究

发布时间：2018-03-09 11:24

本文选题：脱硫废水　切入点：液滴蒸发　出处：《西安建筑科技大学》2015年硕士论文　论文类型：学位论文

【摘要】：随着我国火电建设力度的加大和环保要求的提高,火电厂烟气排放中二氧化硫的治理工作将更加深入。湿法脱硫工艺作为烟气脱硫的主导工艺被广泛采用,其比例已占到脱硫装机总容量的84%,目前世界上技术最成熟的脱硫工艺是最具优势的石灰石--石膏法。在湿式石灰石洗涤烟气脱硫工艺中,烟气中的氯化物会溶解,使得脱硫洗涤液中氯离子的浓度增加,而氯离子浓度的增加会引起脱硫率下降,并影响石膏品质。为了解决这一问题,通常从脱硫工艺系统中排出一定量的废水并补充新鲜吸收液来降低吸收剂中氯离子的浓度,排出的这部分废水就是脱硫废水。脱硫废水中含有大量的氯离子、氟化物、亚硝酸盐等;重金属离子,如:铜、汞离子等;不可溶的硫酸钙及细尘等。针对废水成分特点,废水处理工艺主要采用石灰中和、絮凝澄清处理,但为去除一些金属离子需加入特殊的铁络合物和聚合物药品作为辅助絮凝剂,采用化学方法处理后的废水中氯离子含量高,导致处理后的废水无法进入系统回用,而且根据国家环保要求脱硫废水不允许排放。基于脱硫废水难处理的问题,近年来发展的以液滴蒸发进行废水处理的工业应用崭露头角,它是将废水雾化喷入空气预热器和电除尘器之间的烟道,利用热烟气把废水蒸发,废水中的可溶性固形物转化为结晶盐类固体,连同废水中的颗粒物,经过PCD装置(颗粒物控制装置)与飞灰一起被收集从而实现废水的零排放。本文主要对废水在烟道中的蒸发条件进行计算,分析烟道废水蒸发对除尘器及脱硫的影响。
[Abstract]:With the increase of thermal power construction and the improvement of environmental protection requirements, the treatment of sulfur dioxide in flue gas emissions from thermal power plants will be further deepened. The wet desulfurization process is widely used as the leading technology of flue gas desulfurization. At present, the most mature desulfurization technology in the world is the most advantageous limestone gypsum process. In the wet limestone washing flue gas desulfurization process, the chloride in the flue gas will dissolve. In order to solve this problem, the concentration of chlorine ion in desulfurization washing solution is increased, and the concentration of chlorine ion will cause the decrease of desulphurization rate and affect the quality of gypsum. A certain amount of waste water is usually discharged from the desulfurization process system and fresh absorbent solution is added to reduce the concentration of chlorine ion in the absorbent. This part of the waste water is the desulfurization wastewater, which contains a lot of chlorine ions, fluoride, etc. Nitrite and so on; heavy metal ions, such as copper and mercury ions; insoluble calcium sulfate and fine dust, etc. According to the characteristics of wastewater composition, the wastewater treatment process mainly adopts lime neutralization, flocculation clarification, etc. However, in order to remove some metal ions, special iron complexes and polymer drugs should be added as auxiliary flocculants. The wastewater treated by chemical method has high chlorine ion content, and the treated wastewater cannot be reused in the system. In addition, according to the national environmental protection requirements, desulphurization wastewater is not allowed to be discharged. Due to the difficult treatment of desulphurization wastewater, the industrial application of droplet evaporation for wastewater treatment has emerged in recent years. It is to spray the waste water into the flue between the air preheater and the electrostatic precipitator. The waste water is evaporated by hot flue gas, and the soluble solids in the wastewater are converted into crystalline salt solids, together with the particles in the wastewater. The zero discharge of waste water was realized by PCD device (particle control device) and fly ash. The evaporation conditions of waste water in flue were calculated and the influence of evaporation on dust collector and desulfurization was analyzed.
【学位授予单位】：西安建筑科技大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：X773

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