稠油污水回用热采锅炉深度除硅实验研究

Study on extended silicon removal in heavy oil produced water recovering for thermal boilers

对辽河曙光采油厂稠油污水进行除硅处理研究。提出用全硅法测定ρ(硅)作为稠油污水除硅剂研究的评价方法,并与活性硅法测定值进行了对比。优选除硅剂单剂,考察复配除硅效果,研究了不同复配比及加剂量对除硅效果的影响。用显微镜观察了聚合氯化铝(PAC)除硅前后沉积物的形态并分析了除硅机理。实验证明,采用活性硅法测定ρ(硅)时MgO与PAC除硅效果好,常用熟石灰及氯化钙无明显除硅效果。采用全硅法测水中的ρ(硅)证明氧化镁对水中溶解硅去除效果好,对不溶性硅聚沉去除效果差,而PAC对水中不溶性硅有较好的聚沉去除作用;最佳m(MgO)∶m(PAC)=3∶1,ρ(除硅剂)=400mg/L时,2种方法测得的ρ(硅)均低于50mg/L,复配强化了除硅效果,满足现场除硅指标。氧化镁主要是表面水化层与SiO23-结合生成MgSiO3而去除硅,PAC可吸附SiO23-并破坏胶体硅稳定性,将溶解硅与不溶硅聚集沉降去除。

The heavy oil produced water from Shuguang Oil Production Company was treated to re- move silicon in this thesis. Adopt determination of all-silicon content as evaluation method to analyze the effects of Si removal of several agents, the value of determination was compared with that of Si-Mo Spectro Photometry. Meanwhile,the influences of various composite ratios and dosage of compound a- gents on the effects of Si removal were investigated. The microscope was used to observe deposits in produced water after treatment with PAC. The result showed that magnesium oxide and PAC present the best Si removal effects, but slaked lime and calcium chlorides have no obvious effects. Determine all-silicon content showed that PAC has a better removal effect on activated silica and non-activated silica than magnesium oxide. When the composite dosage is 400 mg/L the contents of total-silicon and activated silica after treatment with combined use of and 3 ： 1 magnesium oxide and PAC can satisfy the requirements of the site. The hydrated surface layer of magnesium oxide reacts with silicate ion and comes out as magnesium silicate so that silicon can be removed. PAC not only can remove silicate ion to destroy colloid stability, but also can gather all-silicon and settle them to remove silicon.