煤制氮肥厂废水氨氮预处理及回收研究

发布时间：2018-07-26 13:56

【摘要】：氨氮是造成水体富营养化的关键因素,随着工业的发展,越来越多的含氮工业废水被排入江河湖泊中,为水体带来了极大的隐患。高浓度工业氨氮废水成分复杂,污染物含量高,难处理,在排入城市污水处理系统前,应进行预处理降低氨氮浓度,以减少城市污水处理系统负荷。同时,氨氮被广泛添加到各类肥料中,废水脱氮的同时,氨氮资源化回收的研究具有重要意义。本文对陕西省某煤制氮肥厂废水进行了污染源调查,并采用膜化学反应器与中空纤维膜分离法对氨氮废水进行了脱氮处理。膜化学反应器将鸟粪石沉淀法与膜分离技术结合处理氨氮废水,研究了氨氮去除率、出水浊度、鸟粪石回收情况。在废水p H为8~9并不调节废水p H的情况下,用中空纤维膜分离法处理氨氮废水,并使用不同浓度的硫酸溶液作为分离液,研究初始浓度、硫酸溶液浓度以及流向对于氨氮去除率的影响。研究得出以下主要结论:(1)使用德士古气化炉的煤制氮肥厂所排放的废水中,气化废水,变换常温冷凝液,火炬液封水的水量、氨氮浓度、COD均较大,变换常温冷凝液可回用至磨煤工段,主要处理对象是气化废水及火炬液封水,气化废水氨氮浓度为180~500mg/L,火炬液封水氨氮浓度为1500~1800 mg/L。(2)用膜化学反应器处理氨氮浓度为192.88 mg/L的气化废水,选择Mg Cl2·6H2O和Na2HPO4·12H2O作为沉淀剂,药剂投加比为n(NH4+):n(Mg2+):n(PO43-)=1:1:1,氨氮去除率超过90%。出水浊度为20度,相较于进水,出水浊度降低了50%左右,相较于分离池,出水浊度降低了85%以上。在分离池持续曝气,可减缓膜通量的降低速率。鸟粪石的回收率可达94.29%。(3)将0.3 mol/L、0.4 mol/L、0.5 mol/L的硫酸溶液作为分离液,用中空纤维膜分离法对浓度为274 mg/L、380 mg/L、478 mg/L的废水进行脱氮处理。氨氮的去除率为34%~50%。采用中空纤维膜分离法处理氨氮废水时,氨氮的去除率会随废水初始浓度的增加而降低,也会随硫酸溶液浓度增大而提高,当氨氮废水和硫酸溶液在中空纤维膜内流向相同时,氨氮去除率稍大于反向时。
[Abstract]:Ammonia nitrogen is the key factor of eutrophication of water body. With the development of industry, more and more industrial wastewater containing nitrogen is discharged into rivers and lakes, which brings great hidden trouble to water body. The wastewater with high concentration of ammonia nitrogen is complex in composition, high in pollutant content and difficult to treat. Before discharging into the municipal wastewater treatment system, pretreatment should be carried out to reduce the concentration of ammonia nitrogen in order to reduce the load of municipal wastewater treatment system. At the same time, ammonia nitrogen is widely added to all kinds of fertilizers, and it is of great significance to study the recovery of ammonia nitrogen resource while the wastewater is denitrified. The pollution sources of wastewater from a coal nitrogenous fertilizer plant in Shaanxi Province were investigated, and the ammonia nitrogen wastewater was treated by membrane chemical reactor and hollow fiber membrane separation method. The ammonia nitrogen wastewater was treated by a membrane chemical reactor. The removal rate of ammonia nitrogen, the turbidity of effluent and the recovery of bird dung stone were studied. Under the condition that the pH of the wastewater is 8 ~ 9, the ammonia nitrogen wastewater is treated by hollow fiber membrane separation method, and the initial concentration is studied by using different concentrations of sulfuric acid solution as the separation solution. The effect of concentration and flow direction of sulfuric acid solution on ammonia nitrogen removal rate. The main conclusions are as follows: (1) in the wastewater discharged from the coal nitrogen fertilizer plant with Texaco gasifier, the amount of water in gasification wastewater, the change of condensate at room temperature, the amount of water sealed by flare liquid, and the concentration of ammonia and nitrogen in nitrogen fertilizer plant are all relatively large. The condensate at normal temperature can be reused to the coal mill section, and the main treatment object is gasification wastewater and flare liquid sealing water. The ammonia nitrogen concentration of gasification wastewater was 180 ~ 500mg / L and the concentration of ammonia nitrogen in water was 1500 ~ 1800mg / L. (2) the gasification wastewater with ammonia nitrogen concentration of 192.88 mg/L was treated by membrane chemical reactor. Mg Cl2 6H2O and Na2HPO4 12H2O were selected as precipitators. The ratio of adding agent was n (NH4): n (Mg2) n (PO43-) 1: 1: 1, and the ammonia nitrogen removal rate exceeded 90%. Compared with the influent, the turbidity of the effluent decreased by about 50%, and the turbidity of the effluent decreased by more than 85% compared with the separation tank. Continuous aeration in the separation tank can slow down the reduction rate of membrane flux. The recovery rate of bird dung can reach 94.29. (3) the sulfuric acid solution of 0.3 mol / L ~ (0.4) mol / L ~ (0.5) mol/L was used as the separation solution, and the wastewater with a concentration of 274 mg / L ~ (380) mg / L ~ (478) mg/L was treated with hollow fiber membrane separation method. The removal rate of ammonia nitrogen is 34% and 50%. When the ammonia nitrogen wastewater is treated by hollow fiber membrane separation, the removal rate of ammonia nitrogen decreases with the increase of the initial concentration of the wastewater and increases with the increase of the concentration of sulfuric acid solution. When the flow of ammonia nitrogen wastewater and sulfuric acid solution is the same in the hollow fiber membrane, The removal rate of ammonia nitrogen is slightly higher than that of reverse.
【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】：X786

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