压裂返排液物理化学法达标治理研究

ON THE TREATMENT OF DISCHARGE OF FRACTURING FLUID WITH PHYSICAL AND CHEMICAL METHODS TO MEET DISCHARGE STANDARD

以油气田作业现场的仪陇-1井压裂返排液为研究对象,通过对其来源、水质特征、治理现状进行分析,提出预氧化复合混凝—Fenton试剂深度氧化—二次混凝的处理工艺。通过实验研究,确定了氧化剂Mn-1,筛选了适合的混凝剂(PAC和PAJ),通过正交实验获得的最佳工艺条件为:Mn-1、碱化剂、PAC、PAJ投加量分别为2250、2500、5000,4000 mg/L;PAC与PAJ质量比为1.25。Fenton试剂深度处理的工艺条件为:H2O2(30%)与废水体积比为0.4%,FeSO4投加量为2400 mg/L,pH为4~6,反应时间为2.5~3.0 h。采用上述处理工艺,处理后废液的主要污染物指标COD降低84.8%,从而为达标深度处理创造了条件。

Taking fracturing fluid used in Yi Long well 1 as example,according to the analysis of fluid source,quality characteristics and current treatment condition,the process of pre-oxidation-coagulation H2O2/Fe2+ catalytic oxidation,second coagulation put is forward in this paper.Based on series of experimental research in the lab,Mn-1 is chosen as oxidantion agent,proper coagulants(PAC and PAJ) is selected.Meanwhile,through orthogoral experiment,and the best conditions in the course of the oxidation and coagulation are optimized and determined.The best reaction conditions are Mn-1 2 250 mg/L,NaOH 2 500 mg/L,duplicate matching proportion 1.25,PAC 5 000 mg/L and PAJ 4 000 mg/L;The best reaction conditions of Fenton agent are H2O2(30%) 0.4%(Vt),FeSO4 2 400 mg/L,pH 4 to 6,reaction time 2.5 h to 3.0 h.After the treatment outlined above,the COD(Chemical Oxygen Demand),one of the most important pollutant index,can be reduced by 84.80%,which creates certain conditions for the further disposal.