聚硅酸盐混凝剂处理压裂返排液的效果及影响因素

Effect and Influence Factors of Poly-silicic-cation Coagulant in Fracturing Flowback Fluids Treatment

李冉 潘杰 张丽 屈肖 杨江 秦文龙

LI Ran，PAN Jie，ZHANG Li，QU Xiao，YANG Jiang，QINWenlong

为提高压裂返排液化学处理效率、降低后续深度处理工艺负荷，采用自制聚硅酸盐混凝剂（PSiC）对返排液进行混凝预处理，利用Box-Behnken 设计建立连续变量曲面模型进行Si 浓度、聚合pH、Si/（Al+Fe）摩尔比（Fe/Al摩尔比9∶1）3 因素3 水平实验设计，考察了这3 种因素对PSiC 混凝效果的影响，确定出合适的制备参数。进一步利用统计软件Design Expert 对实验数据进行多元回归拟合，并通过三维立体图像揭示三种因素交互作用规律。研究结果表明，Si/（Al+Fe）摩尔比对PSiC 混凝效果和稳定性影响较大，当Si 浓度、Si/（Fe+Al）比和pH值分别取3.41%、1.3、1.8 时，PSiC 具有最佳的混凝性能，投加量为130 mg/L（以铁铝和计）时压裂返排液的浊度去除率和COD去除率分别为88.52%和70.35%。Si 浓度、聚合pH、Si/（Al+Fe）摩尔比与处理效果之间的二次多项回归模型方程显著、可靠。Si 浓度和Si/（Fe+Al）比交互作用不显著，Si 浓度和pH有一定的交互作用，Si/（Fe+Al）比和pH交互作用较显著。图9表5 参12

In order to improve the efficiency of chemical treatment of fracturing flowback fluids，and reduce the load of subsequent treatment process，the poly-silicic-cation coagulant（PSiC）was prepared to treat fracturing flowback fluids. Through Box-Behnken experiment design and response surface analysis，optimization grouping of Si concentration，polymerization pH，Si/（Al+Fe）molar ratio was realized，a quadratic response surface model and optimum level values were obtained. The experimental data were multivariable regression fitting by the statistical software Design Expert. Three-dimensional images were used to reveal interaction between three factors. The results showed that coagulation performances and stability were significantly influenced by the Si/（Fe+Al）molar ratio. It was found that the optimization grouping of the main influence factors for coagulation were as following：Si concentration，pH value and Si/（Al+Fe）molar ratio being of 3.39%，1.3 and 1.8，respectively，and the removal rate of turbidity and COD were 88.52% and 70.35% ，respectively，with the active ingredient （Fe + Al） dosage of 130 mg/L. The quadratic polynomial regression equation model of Si concentration，polymerization pH，Si/（Al+Fe）molar ratio and treatment effect was significant and reliable. The interaction between Si concentration and Si/（Al+Fe）molar ratio was not significant，and there was some kind of interaction between Si concentration and pH，while the interaction between Si/（Al + Fe）molar ratio and pH was significant.

10.19346./j.cnki.1000-4092.2017.04.027