燃煤电厂湿法烟气脱硫废水零排放处理技术研究

发布时间：2018-02-20 08:12

本文关键词： 脱硫废水物化法零排放吸附蒸发结晶　出处：《武汉科技大学》2015年硕士论文　论文类型：学位论文

【摘要】：燃煤电厂脱硫废水污染物种类繁多,悬浮物、含盐量、重金属离子(镉、汞、铬、铅、镍等)、氟化物、硫化物、COD等指标含量都超过国家排放标准,对环境的污染性很强,若直接排放,将严重影响环境,进一步威胁人们的身体健康。因此,研究脱硫废水综合利用技术,通过废水回用,实现脱硫废水“零排放”,有重要的环境效益、经济效益以及社会效益。本文主要通过正交试验确定了物化法及吸附法对江苏某燃煤电厂脱硫废水预处理的最优操作参数,再采用蒸发结晶法对预处理后的脱硫废水进行深度处理,回用废水并回收废水中的工业盐,实现脱硫废水零排放。本论文主要研究结果如下:物化法主要包含中和沉淀、硫化物沉淀和混凝,正交试验确定的燃煤电厂脱硫废水物化法预处理的最佳工艺条件为:中和沉淀反应的pH=9,搅拌速度200 r/min,搅拌时间20 min,镉、铅、镍离子的去除率分别为97.14%、69.13%及79.81%;硫化物沉淀反应控制硫化钠加入量21 mg/L,搅拌速度200 r/min,搅拌时间40 min,铅离子去除率达80.94%;混凝反应加入混凝剂PAFS 2.5 mL/L和助凝剂PAM 2.0mL/L,浊度降低了91.3%。以生物炭为原料,制备出KOH活化、磁性和赋硫三种生物质活性炭;改性制备的三种生物质活性炭的各项孔结构参数均大于未改性的原料生物炭;KOH改性的活性炭的酸性基团羧基显著增加,内酯基减少;磁性活性炭的羧基略有增加,内酯基和酚羟基减少,羰基增加;赋硫活性炭的羧基增加,内酯基和羰基减少。实验考察了pH值、温度、时间三种吸附条件对Pb(Ⅱ)、Cd(Ⅱ)、Ni(Ⅱ)的吸附影响,研究结果表明三种重金属离子的最佳吸附pH值均为6;脱硫废水的吸附过程中,各种重金属离子之间存在竞争吸附,去除效果为Cd(Ⅱ)Ni(Ⅱ)Pb(Ⅱ),镉抑制铅和镍的吸附,综合比较,磁性活性炭对重金属离子混合体系的吸附效果较好。蒸发结晶深度处理时,当蒸发速率为50 mL/h,加入2%晶种时,得到的工业盐粒度分布均匀,平均粒度达414μm;工业盐产品质量达到GB/T 5462-2003《工业盐》的国家精制工业盐二级标准;冷凝水水质达到GB/1576-2008《工业锅炉水质》的给水标准。
[Abstract]:The coal-fired power plant desulfurization wastewater pollutant variety, suspended solids, salinity, heavy metals (cadmium, mercury, chromium, lead, nickel), fluoride, sulfide, COD and other indicators were more than the national emission standards, environmental pollution is very strong, if the direct emissions, will affect the environment seriously, further threatening the people health. Therefore, the comprehensive utilization technology of desulfurization wastewater, the wastewater reuse, the desulfurization wastewater "zero emissions" has significant environmental benefits, economic benefits and social benefits. This paper mainly through orthogonal test to determine the physicochemical method and adsorption method for the optimal operation parameters of pretreatment desulfurization wastewater in a coal-fired power plant in Jiangsu then, the evaporation crystallization method for the advanced treatment of desulfurization wastewater after pretreatment, wastewater reuse and recycling of industrial salt wastewater, desulfurization wastewater to achieve zero emissions. The main results are as follows: the main physicochemical method Including neutralization precipitation, sulfide precipitation and coagulation, orthogonal test to determine the coal-fired power plant desulfurization wastewater by physicochemical pretreatment and the optimum conditions were: the precipitation reaction of pH=9, stirring speed of 200 r/min, stirring time 20 min, cadmium, lead, nickel ion removal rates were 97.14%, 69.13% and 79.81%; sulfide precipitation the reaction control of sodium sulfide dosage 21 mg/L, stirring speed of 200 r/min, stirring time of 40 min, the lead ion removal rate was 80.94%; the coagulation reaction adding coagulant and coagulant aid PAFS 2.5 mL/L PAM 2.0mL/L, 91.3%. in turbidity reduced biological carbon as raw material, prepared by KOH activation, magnetic and sulphur of three kinds of biomass activity carbon; the pore structure parameters of three kinds of biomass activated carbon prepared were higher than that of unmodified carbon raw materials; carboxylic acid groups of KOH modified activated carbon increased significantly, lactone reduction; magnetic activated carbon with carboxyl radical Increase, lactone and phenolic hydroxyl carbonyl reduction, increasing sulphur; activated carbon increased lactone carbonyl and carboxyl, reduced. The effects of pH value, temperature, time of the three kinds of adsorption conditions on Pb (II), Cd (II), Ni (II) the effect of adsorption, the results show that the optimum adsorption of pH three kinds of heavy metal ions was 6; adsorption desulfurization wastewater, the competitive adsorption existed between various heavy metal ions, the removal effect of Cd (II) Ni (II) Pb (II), the adsorption of cadmium, lead and nickel in the suppression of a comprehensive comparison, better absorption effect of magnetic activated carbon mixed system for heavy metal fitting the depth of treatment. Ion evaporation and crystallization, when the evaporation rate is 50 mL/h, with 2% seed, the granularity of industrial distribution, the average particle size of 414 mu m; refining industrial salt two national standard of industrial product quality reached GB/T 5462-2003< salt industrial salt >; water quality reached the GB/1576-2008< industry Water quality of boiler > water supply standard.

【学位授予单位】：武汉科技大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：X773

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