电气浮法处理炼油循环水旁滤器反冲水研究

西北某炼油厂4套敞开式循环水系统冷却塔易混入空气中的灰尘杂质,并滋生细菌、藻类等,导致循环水水质变差。该厂采用旁流过滤技术净化循环水水质,且旁流过滤器反冲水水量大,回收利用很有必要。本文采用电气浮法和混凝法+电气浮法进行了废水处理试验。试验结果表明:静态电气浮法和动态电气浮法在不加入介质调节电导率、电流为1.1A(即电流密度为0.016A/cm2)、pH值为5.5、电极间距为5mm、气浮时间大于40min的试验条件下,可使废水处理后达到回用的基本要求;根据电压、电流和动态电气浮法所能处理的最大流量(157.1mL/min),可计算出电气浮法每吨水电耗约1kW·h;试验结果显示,电气浮法+混凝法处理的工艺效果不好,反而使处理过程复杂化;动态电气浮法试验能使出水达到回用要求且杀菌能力强,避免回用后细菌在循环水系统内繁殖而影响正常生产。

A Study into Using Electro-Coagulation-Floatation Method to Treat Backwash Water of Side Filter for Refinery Circulating Water

The cooling tower of four open-type circulating water systems of a refinery in northwestern China is subject to influence of dust and other impurities in the air,causing the breeding of bacteria and algae and a deterioration of the quality of circulating water.The refinery adopted side filter technology to purify the circulating water.As the flow of backwash water of the side filter is very large,it is necessary to recover the backwash water.Technicians conducted a wastewater treatment experiment using the electro-coagulation-floatation method and the coagulation plus electro-coagulation-floatation method.The experiment shows that：wastewater treated using both the static and dynamic electro-coagulation-floatation methods meets the basic requirements for reuse when no medium is added to adjust the electrical conductivity and when the current stands at 1.1A（i.e.the current density is 0.016A/cm2）,the pH value is 5.5,the electrode spacing is 5mm and the floatation duration is greater than 40min;based on voltage,current and the maximum flow that can be treated by the dynamic electro-coagulation-floatation method（157.1mL/min）,we can calculate that the electricity consumption in treating one ton of water using the electro-coagulation-floatation method is about 1kW·h;the combined use of the electro-coagulation-floatation method and the coagulation method did not yield good results but complicated the treating process;the dynamic electro-coagulation-floatation method can produce water meeting the requirements for reuse and has strong sterilization ability,which can prevent bacteria from breeding in the circulating water system after water recycling,thus preventing production from being affected.