稠油污水蒸发前除硅及有机物的试验研究

Experimental Study on Silica and Organic Matter Removal from Heavy Oil Wastewater Before Evaporation

稠油污水是油田地区建设热电厂的重要水源,其温度、含盐量、SiO_2和有机物浓度较高。为了使用蒸发脱盐工艺处理稠油污水,采用化学反应和强化混凝技术进行了除硅、除有机物的研究,以降低蒸发器结硅垢的倾向并提高蒸发产水水质。试验结果表明,联合投加Ca(OH)_2、MgCl_2·6H_2O及净水剂PAC、PAM,在最优工艺条件下,出水全硅可降至25.5 mg/L,全硅去除率为89.5%。气相色谱-质谱联用仪(GC-MS)测定结果显示,稠油污水及预处理出水中主要有机物成分均为有机酸、含氮化合物,预处理对有机酸类有明显去除,但对挥发性有机物影响不大。

The heavy oil wastewater, which is of high temperature, high salinity, SiO2 and organic matter concentrations, is the major raw water source for the thermal power plants built in oilfield areas. To conduct the heavy oil wastewater treatment with evaporation desalination technique, the study on silica and organic matter removal is performed using chemical reaction and enhanced coagulation technology to reduce the risks of silica scaling in the evaporator as well as to enhance the quality of the evaporation water product. The experimental results show that with the joint Ca（OH）2, MgCl2·6H2O, PAC and PAM dosing and under the optimal processing condition, the effluent total silica concentration is decreased to 25.5 mg/L and its removal rate reaches as much as 89.5%. The gas chromatography-mass spectrometer（GC-MS） analysis results indicate that the predominant organic compounds in the heavy oil wastewater and the effluent of its pretreatment process are organic acids and nitrogen compounds. The pretreatment process can remove the organic acids notably but has little effect on VOCs removal.