页岩气压裂返排液复合絮凝处理优化

OPTIMIZE COMPOSITE FLOCCULATION OF FRACTURING BACKFLOW LIQUID AT SHALE GASFIELD

采用丙烯酰胺改性壳聚糖(CTS),合成了改性生物絮凝剂XU1、XU2、XU3,通过其对页岩气压裂返排液的处理效果,筛选出性能最好的XU2,并将其与聚合氯化铝(PAC)复配形成复合絮凝剂。考察了复合絮凝剂对压裂返排液的处理效果并通过正交实验方法确定了最佳复合絮凝条件,即:改性生物絮凝剂浓度10 mg/L;聚合氯化铝浓度30 mg/L;慢速搅拌强度60 r/min;沉降时间30 min。最佳絮凝条件下,复合絮凝剂对压裂返排液中COD去除率55%以上,浊度去除率95%以上。

The bioflocculants XU1,XU2,XU3 were synthetized by modifying chitosan using acrylamide. Due to its best performance in terms of treating shale gas fracturing backflow liquid,XU2 was used to compound with polyaluminium chloride( PAC) to form the composite flocculants. The performance of the composite additive was examined. And the best composite flocculation conditions were determined through orthogonal experiments,including modified bioflocculant content 10mg/L,PAC content 30mg/L,agitation speed 60 rpm,and settling time30 min. Under the optimal flocculating conditions,COD removal was above 55%,turbidity removal above 95%.