过一硫酸盐/高铁酸盐体系处理页岩气压裂返排液实验研究

Experimental Study on the Treatment of Shale Gas Fracturing Flowback Fluid by Persulfate/Ferrate System

针对高盐难降解的页岩气压裂返排液,探究过一硫酸盐(PMS)/高铁酸盐(Fe(VI))体系氧化其中有机物的可行性。对比了活化PMS的不同方式及不同氧化工艺;设计了L_(16)(4~4)正交实验优化氧化反应参数;考察了该体系在氧化的同时达到的混凝和软化效果。结果表明,PMS/Fe(VI)体系在最佳反应条件下(即PMS的浓度为1 800 mg/L,Fe(VI)浓度为1 200 mg/L,pH为5,反应温度为35℃时)TOC的去除率为46.4%,其中各因素的贡献值分别是19.34%、51.31%、15.38%、13.68%。在高效矿化有机物的同时能去除返排液中99.5%的总悬浮固体(TSS)和95.2%的Ba^(2+)。研究结果可为页岩气压裂返排液预处理工艺单元的设计和运行提供参考。

The feasibility of peroxymonosulfate(PMS)/ferrate(Fe(VI)) system for oxidizing organics in shale gas fracturing flowback fluid with high salt and low degradation was investigated.Different ways of activating PMS and different oxidation processes were compared.The L_(16)(4~4) orthogonal experiment was designed to optimize the oxidation reaction parameters.The coagulation and softening effects of the system during oxidation were investigated.The results showed that the TOC removal rate of PMS/Fe(VI) system is 46.4% under the optimal reaction conditions(i.e.,the concentration of PMS is 1 800 mg/L,the concentration of Fe(VI) is 1 200 mg/L,the pH value is 5,and the reaction temperature is 35 ℃).The contribution values of each factor were 19.34%,51.31%,15.38% and 13.68%,respectively.At the same time,99.5% of total suspended particulates(TSS) and 95.2% of Ba~(2+) were removed from the flowback fluid.The research results can provide a reference for the design and operation of shale gas fracturing flowback fluid pretreatment process unit.