摘要：

对页岩气开采中压裂返排液的组成、特性及处理现状进行分析,提出采用破胶混凝-磁分离-电化学催化氧化技术处理压裂返排液.研究得到各处理单元优化工艺,其中破胶混凝工艺采用高铁酸钾破胶剂、投加量2500mg/L,混凝剂聚合氯化铝铁投加量为2000mg/L,反应pH为11.0,反应时间40min;磁分离工艺采用纳米磁铁粉,投加量4000mg/L,高分子絮凝剂阴离子聚丙烯酰胺投加量为20mg/L;电化学催化氧化工艺采用Ti/TiO₂作阳极,不锈钢作阴极,氧化电压10.0V,电流密度1.6×10^-2A/cm²,体系pH为11.0,反应时间30min.研究结果表明,采用上述技术及优化工艺处理压裂返排液,处理后COD、SS、油、色度、pH等主要指标均达到GB8978-2002的一级排放标准要求.

关键词: 页岩气, 压裂返排液, 混凝, 磁分离, 电化学催化氧化

Abstract:

The components,characteristics and treatment actuality of fracturing flow-back fluid fromshale gas explo-ration are analyzed. It is put forward that the gel-breaking coagulation-magnetic separation-electrochemistry catalysis oxidation technology is used for treating fracturing flow-back fluid. The optimized technology of every treatment unit is obtained through researches,among which gel-breaker K₂FeO₄ is used in the gel-breaking coagulation process. The conditions needed are as follows:the dosage of K₂FeO₄ is 2 500 mg/L,PAFC dosage 2 000 mg/L,reacting pH 11.0 and reaction time 40 min. Nano-magnet powder 4 000 mg/L and polymer flocculant HPAM 20 mg/L are needed for the magnetic separation process. Ti/TiO₂ plate is used as anode,while stainless steel plate as cathode, oxidation voltage 10.0 V,current density1.6×10^-2 A/cm²,reaction pHof the system 11.0 and reaction time 30 min are needed for the electrochemistry catalysis oxidation process. The research results show that after the above technology and optimized processes have been used for the treatment of fracturing flow-back fluid,all of the main factors,such asCOD,SS,oil content,chroma,pH,etc. meet therequirementsspecified in thefirst class of the IntegratedWastewater Discharge Standard(GB 8978-2002).

Key words: shale gas, fracturing flow-back fluid, coagulation, magnetic separation, electrochemistry catalytic oxidation

中图分类号: 

• X703