Research Of Reusing Waste Water Of The Circulating Cooling Water Of Refinery

Circulating cooling water system is an important portion of a refinery, it is indispensable to keep it working stably, measures are taken to avoid the machinery being rusted and being fouled and the growth of bacteria; measures are also taken to reduce consume of water, These measures involved discharge concentrated water form cooling water system, filtrate part of circulating cooling water; The filter is stop up usually because the pollutants of cooling system are excessive, the frequency of backwash is accordingly high and the volume of backwash waste water is great. The intention of this research is to devise techniques for reusing blowdown of circulating cooling water of refinery and the filter backwash waste water, these techniques are supposed to replace lateral filters system.Treat filter backwashing water with flocculation-sedimentation method at first, ascertain optimal pH and optimal amount of several staple inorganic flocculation. Use PAC as inorganic flocculation cooperate with organic flocculation such as PDMDAAC-AM, PDMDAAC, cationic-type PAM, anionic PAM, choose PAC and cationic-type PAM to treat waste water from these flocculation, determine quality of treated water, the result shows that the water quality can meet the standard of circulating cooling water of refinery.Electro-flotation is a briefleness water treatment technique, the results of experiment showed it is an appropriate technique that treat the waste water use electro-flotation without flocculation. Most factors have impacts on efficiency of electro-flotation such as conductance of waste water, pH, electric current density, space between electrodes. The best value of these factors are obtained: electric current density is 0.016A/cm ,pH5.5, space between electrodes is 5mm, electro-flotation time is longer than 40min.test the efficiency of dynamic electro-flotation on these conditions, It makes clear that the water quality can meet the standard of reusing water after treatment of dynamic electro-flotation.Finally, choose PAC as inorganic flocculation and cationic-type PAM as organic flocculation and treat the water with coagulation-dissolved air floatation process on the optimal condition of flocculation-sedimentation. Result shows that dissolve air pressure and flocculation time have slightly impact on coagulation-dissolved air floatation process. There are several virtue of coagulation-dissolved air floatation such as the treated water quality is all right, its efficiency is high; its finally water quality is steady; its flow is brief; the volume of concentrated mud is small and the concentrated mud can be dried easily, the concentrated mud does not need treat again. So it can be choose as semi-works flow.