化学混凝法同步除炼油污水中硅和浊度的研究

Removal of silicon and turbidity from oil refinery effluent by chemical coagulation progress

关键词:  炼油废水  低温多效蒸发  混凝剂  脱硅除浊度 

Key words:  oil refinery effluent  low temperature multi-effect evaporation  coagulation  silicon and turbidity removal

摘要:

炼油厂污水经A²/O为核心的生化系统处理后,水质可达到污水综合排放标准。 有效利用炼油厂低温余热,通过负压多效蒸发工艺实现净化后污水的回收再利用,是炼油厂节能减排的新举措。进水水质中硅、浊度是蒸发工艺防垢、控制水质的主要参数,以硅、浊度的同步去除为目标,研究了石灰、镁盐沉淀、铁铝盐共沉淀法对硅和浊度去除效果的影响。结果 表明,当Ca(OH)₂的投加量为500 mg/L时,硅、浊度的同步去除率分别为79.2%和4.2%；pH值=10.0,MgCl₂投加量为400 mg/L时,硅、浊度的同步去除率分别为91.6%和74.4%；优选的Fe(Ⅱ/Ⅲ)Al复合混凝剂投加量为400 mg/L时,硅、浊度的同步去除率分别为91.9%和90.4%。Fe(Ⅱ/Ⅲ)Al复合混凝剂作用效果满足蒸发系统对进水硅和浊度的控制要求,处理后硅含量为17.93 mg/L,浊度为3 NTU。 

Abstract:

The oil refinery effluent was dealt with biochemical treatment taking A²/O as a core, and its quality could reach the comprehensive discharge standard of effluent. The effluent could be recycled by the low pressure multi-effect evaporation system using the low temperature heat of oil refinery, and it was the new measure of energy saving and emission reduction. The silicon and turbidity were the main parameters of evaporation process. The removal effect of silicon and turbidity by softening with lime, magnesium salt precipitation and precipitation by combination coagulant of molysite and aluminium salt were researched. The results indicated that:when the dosage of Ca(OH)₂ was 500 mg/L, the removal rate of silicon and turbidity were 79.2% and 4.2%,respectively, and when the dosage of MgCl₂ was 400 mg/L at the pH value of 10, the removal rate of silicon and turbidity were 91.6% and 74.4% ,respectively. The requirement of low temperature multi-effect evaporation system could be achieved, when the dosage of Fe(Ⅱ/Ⅲ)Al combination coagulant was 400 mg/L and the removal rate of silicon and turbidity were 91.9% and 90.4%,respectively. The residual silicon content and turbidity were 17.93 mg/L and 3 NTU.