电催化氧化复合磁分离处理页岩气压裂返排液室内研究

Laboratory study on shale gas flowback water treatment applying electrochemical oxidation coupled with magnetic separation

关键词:  页岩气  滑溜水返排液  电化学催化氧化  磁分离 

Key words:  shale gas  slippery water flowback fluid  electrochemical catalytic oxidation  magnetic separation

摘要:

通过对页岩气开采用滑溜水压裂返排液组成、特性及处理现状分析,结合页岩气开采现场及国家对水资源的资源化利用、环保要求,提出了采用电催化氧化技术及磁分离处理滑溜水压裂返排液研究思路。实验研究了影响电催化氧化技术及磁分离处理的主要影响因素,讨论了电催化氧化作用机理,研究得到处理优化工艺条件。电极板选择铝板电极,极板间距为4 cm；催化剂选择二氧化钛,加量为3.0(w)%；处理时间为40 min；电催化氧化处理电流为0.06 A,电流频率为1 800 Hz；磁铁粉加量为0.3%(w),絮凝剂HPAM加量为20 mg/L。研究表明,采用上述技术及优化工艺条件处理滑溜水压裂返排液,处理后水质COD值、SS、油含量、色度、pH值等指标均达到GB 8978-1996的一级排放要求。 

Abstract:

Through analysis on composition, characteristics, and current treatment options of flowback water arising from slick water using for shale gas fracturing, as well as drilling site survey and state regulations on water resource utilization and environmental protection, this paper proposed treatment process with electrochemical oxidation followed by magnetic separation. Experiments have been conducted to identify the main factors influencing the treatment processes, discussing the function mechanisms of the electrochemical oxidation, and finally achieving the optimum operating conditions. In details, aluminum plate was chosen as electrodes with plate spacing at 4 cm; the catalyst was titanium dioxide with contents equivalent to 3.0%(w); the processing time, electric current of catalytic oxidation processing, and the current frequency were determined to be 40 min, 0.06 A, 1 800 Hz, respectively. Besides, in the magnetic separation process, the dosage of magnetic power and flocculant HPAM was 0.3%(w) and 20 mg/L. Results showed that by applying the proposed treatment process, COD, SS, oil & grease contents, chroma, pH, and other major water quality parameters could meet the first category integrated wastewater discharge standard (GB 8978-1996).