【作者】 李浩；

【导师】 王宗廷；

【作者基本信息】 中国石油大学 ， 化学， 2010， 硕士

【摘要】 酸化压裂作业是油气田增产的主要措施,被各油田普遍采用,但作业过程中会产生大量的返排液返回至地面,返排液具有颜色深、CODCr值高、酸性强、粘度大、难降解等特点。若将返排废液不经处理而直接排放,将会对环境造成严重的污染。针对酸化压裂返排液的水质组成及特点,依据过硫酸铵氧化、微电解处理、Fenton氧化等原理,以CODCr降低率为处理效果的判断依据,提出了“过硫酸铵氧化-微电解-Fenton氧化-沉淀除氟”联合处理工艺,并通过实验优化了各分工艺的实验条件。本论文首先以羟丙基瓜尔胶溶液作为酸化压裂模拟废水(CODCr:752mg/L、pH=3.0、c(F-)= 114.3mg/L)开展了“微电解-Fenton氧化”处理工艺研究,通过单因素实验优化的工艺条件为:(1)微电解实验:m(Fe)/m(C)=5:1,t =90min,pH=2.5,其CODCr降低率可达26.3%;(2)联用Fenton氧化对模拟废水进行深度处理,当10%双氧水加入浓度为7.5mL/L,t=75min,pH=4.0时,CODCr总降低率为38.3%。(3)以Ca(OH)2为F-的沉淀分离剂,当加入浓度为20g/L时,废水中剩余F-浓度为8.5mg/L,符合废水排放标准。在上述工作的基础上,研究了胜利高清区块樊18-9井压裂废水(CODCr:11007mg/L)的联合处理工艺:(1)通过实验优化了过硫酸铵氧化工艺条件:5%(NH4)2S2O8溶液的加入浓度为25.0mL/L,t=30min、进水pH=3.0,其CODCr降低率可达22%;(2)采用铁碳微电解对过硫酸铵氧化后的压裂废水直接进一步处理,当t=120min、m(Fe)/m(C)=5:1时,其CODCr降低率可达35.8%;为进一步改善处理效果,本论文还研究了镀铜铁碳微电解工艺以及微电解池处理级数对处理效果的影响,当t=120min、m[Fe(Cu)]/m(C)= 6:1、微电解池级数为2时,CODCr降低率则提高至58.7%。(3)双级镀铜铁碳微电解后的出水继续采用Fenton氧化法深度处理,当10%双氧水加入浓度为7.5mL/L,pH=4.0,t =60min时,CODCr降低率可达22.6%。压裂废水经联合工艺处理后,CODCr总降低率可达75.6%。本论文的创新性主要为首次提出采用“过硫酸铵氧化-双级镀铜铁碳微电解-Fenton氧化”联合处理工艺深度处理高浓度有机压裂废水,处理效果良好,为酸化压裂废水的处理提供了一种新的方法。同时,通过对比实验对微电解法处理有机废水的工作机理进行了初步探讨,结果表明微电解处理过程是集絮凝、吸附、氧化还原、电富集等因素综合作用的结果,而非简单的絮凝、吸附过程。更多还原

【Abstract】 Fracturing and acidification were adopted popularly by oilfields in order to enhance oil recovery. The fracturing and acidizing wastewater had dull color, high COD value, high acidity, high viscosity, refractory and etc which was produced in the process of fracturing and acidizing operation. If the wastewater was discharged without being treated, the environment would be seriously polluted.This thesis proposed the process integration of“ammoniumpersulfate oxidation– microelectrolysis–Fenton oxidation-defluorination”to treat the fracturing wastewater based on its component, characteristic and according to the mechanism of ammoniumpersulfate oxidation, microelectrolys and Fenton oxidation. The conditions for process were determined on the removal rate of CODCr.The job were done in sequence. Firstly, in order to treat the fracturing and acidizing wastewater, the simulate wastewater of HPG (CODCr:752mg/L、pH = 3.0、CF- = 114.3mg/L) was treated by“microelectrolysis-Fenton oxidation”, and the results were: (1) The removal rate of CODCr was 26.3% in the process of microelectrolysis with the process conditions were: m(Fe)/m(C)=5:1, t=90min,pH=2.5. (2) Under the conditions of t=75min, c[10%H2O2(v/v)]= 7.5mL/L, pH=4.0, the total removal rate of CODCr was 38.3%. (3) Using Ca(OH)2 as precipitant, the concentration of fluorion was 8.5mg/L when the concentration of precipitant was 20g/L.secondly, the fracturing wastewater (initial CODCr:11007mg/L) was treated by the process integration, and the results as follows: (1) The removal rate of CODCr was 22% in the process of oxidation by ammoniumpersulfate under the condition of the reaction time was 30min, c[5%(NH4)2S2O8 (m/m)]=25.0mL/L, pH=3.0. (2) After oxidation operation, the fracturing wastewater was treated by microelectrolysis with the conditions of t=120min, m(Fe)/m(C)= 5:1, and the removal rate of CODCr was about 35.8%. In order to improve the ratio of CODCr removal, copper was electroplated on the surface of iron particles, under the optimum conditions of t=120min, m[Fe(Cu)]/m(C)=6:1, the times was 2, the removal rate of CODCr could reach to 58.7%. The results showed that the removal rate of CODCr was increased by about 20% compared with microeleclysis above. (3) The fracturing wastewater was given to the Fenton reagent oxidation after the reaction of catalytic copper microelectrolysis. The conditions of the advanced oxidation were that: c[10%H2O2(v/v)]=7.5mL/L, pH=4.0, t= 60min, and the removal rate of CODCr 22.6% was got. The total removal rate of CODCr could reach to 75.6% by the process integration (final CODCr:2750mg/L).The innovations of this thesis were that the fracturing wastewater treated by the“four-stages”process integration was implemented for the first time, then a convenient way of treating fracturing and acidizing wastewater was offered. And the mechanism of microelectro- lysis involved flocculation, adsorption, oxidation-reduction, and electro-enrichment which worked coordinately was testified initially.更多还原