Application of Chemical Oxidation-flocculation Process in Boron Removal from Fracturing Flowback Fluid
To reduce the boron content in flowback fluids from hydraulic fracturing and meet the standards for reuse or discharge,the flowback fluids from five horizontal wells after hydraulic fracturing were studied.The effects of oxidant type,dosage,pretreatment conditions,precipitant type,and dosage on the chemical oxidation process were investigated.On the basis of the chemical oxidation process effluent,the influences of coagulant dosage,stirring speed,and dosing interval on the flocculation process were studied,and the effects of their combined use were monitored.The results showed that when H2O2 and BaCl2 were used as oxidant and precipitant,respectively,the boron removal effect was better.Linear equations correlating the optimal dosage with the initial boron concentration in the flowback fluid were established,facilitating the rapid selection of dosing concentrations on-site.When the PAC concentration was 80 mg/L,the PAM concentration was 5 mg/L,the stirring speed was 30 r/min,and the dosing interval was 30 s,the flocculation process exhibited optimal treatment performance.After coupling the chemical oxidation-flocculation process,under conditions of pH 9 for the oxidation reaction,a reaction time of 30 min for oxidation,pH 9 for the precipitation reaction,and optimal flocculation process conditions,the boron mass concentration in the filtrate could be maintained below 5 mg/L,meeting the requirements for reuse.These findings provide practical reference for the efficient and clean treatment of hydraulic fracturing flowback fluids.
chemical oxidationflocculationfracturing flowback fluidboronoxidantprecipitant
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维普
