The Research Of Reuse Technology For Recirculating Cooling Water Sewage In Refinery Enterprise

In order to ensure long-term stable operation of a circulating cooling water system, we need to discharge sewage on a regular basis. Apart from a lot of salt,a variety o f water treatment chemicals are still contained in the circulating cooling water sewage for the sake of corrosion prevention,scale prevention and sterilization.If we can do some treatments to the circulating cooling water sewage to make it as the supplementary water for circulating cooling water system or even to the boiler, we can save a lot of fresh water and improve its utilization efficiency, which can bring considerable economic benefits to the company while reducing environmental pollution.According to the characteristics of circulating cooling water sewage, this paper adopted coagulation+clarify+quartz+sand filter+activated carbon adsorption+reverse osmosis desalination as circulation cooling water sewage treatment system, which can make the sewage meet the water quality standard to reuse as make-up water for circulating cooling water.On this basis the influence of the water quality on the corrosion and microorganism growth of circulating water system was also investigated.At the same time, tetradecyl dimethyl benzyl ammonium chlorine (1427)、Amino Trimethylene Phosphonic Acid (ATMP) and1-Hydroxy Ethylidene-1,1-Diphosphonic Acid (HEDP) were chosen as the representatives to investigate the effect of residual sewage water treatment reagent on coagulation clarification. The experiments showed that:(1)the treatment process in this paper was efficient to the circulating cooling water sewage, its removal rate of COD was94%, the removal rate of chloride ion, sulfate, total hardness reached more than98%, the effluent water quality indexes were turbidity,-0.3NTU, chloride ions5.0mg/L, sulfate ion2.2mg/L, COD4.7mg/L, total hardness18.7mg/L, which had already met the water quality standards of make-up water for circulating cooling water; The residual water treatment chemicals in the circulating cooling water can greatly influence for the coagulation. In the range of the experimental concentration,1427had the greatest influence on turbidity and settling velocity of the flocs, which could decrease the turbidity from1.98NTU to8.81NTU, the sedimentation rate reduced from2.92mm/s to1.38mm/s, HEDP had a great impact on the sludge volume and chemical oxygen demand(COD), it can reduce the sludge volume from15.5mL to6.0mL and increase COD from45mg/L to110mg/L, ATMP had the biggest influence on the compressive degrees of the sludge, which can increase it from2.53to4.24. The influences of residual water treatment chemicals on coagulation effect had a positive correlation relationship with the chemical concentrations in water; The reuse of the treated water from Circulating water sewage could make the circulating water system corrosion and microorganism growth under control:with the increase of the treated water reuse ratio, the corrosion rate became lower and the control of corrosion became better; with the increase of the treated water reuse ratio, the quantity of microorganism became less, the inhibitory to microorganism growth became better.