Application And Research Of Ultrafiltration And Reverse Osmosis On Treatment Of Circulating Cooling Water

Special phenomenon of fouling and corrosion in the central air conditioning circulating cooling water system is comparison seriously, it reduces efficiency of heat exchangerso The existing chemical cleaning out not only causes pollution, but also reduces the nature life of equipments. This paper have combined ultrafiltration(UF) and reverse osmosis(RO) to deal with circulating cool water and anti-fouling, it is rarely studied.UF and RO are used to treat parts of circulating cooling water, then the permeate water of RO is made up to circulating cooling water, it will reduce that water quality of circulating cooling water is stable on a low certain rage to reaching the aim of anti-fouling and anticorrosive.The experiment is made up by UF and RO which are made in china. Firstly circulating cooling water is treat by UF and RO, The feasibility and the optimum operating conditions of UF and RO followed by RO are tested through a series of experiments.In this paper,the best pressure of UF is 0.1MPa, then this paper uses discrete data analyzing method(slope change point analysis)to analyze the changes of ultrafiltration permeate flux without backwash and under different backwash periods, and this data analysis approach to determine the optimal period of online backwash is effective. The optimal period of online backwash is 15min in this paper.Turbidity, SDI, residual chlorine of permeate water of UF are better than RO's demands of feed, it will not effect RO, the average of turbidity is 0.14NTU, SDI is less than 2.5 and residual chlorine is less than 0.02 mg/L. UF can removes mostly microorganism, the removing rate is 94%; After using 1%HCl and 200mg/LNaClO cyclic wash, the permeare flux of UF could be up to original flux.RO can remove effectively various ions in wastewater, the average conductance of permeate of RO is 20.6μS/cm, pH is 7.7, and the average desalinization ratio of RO is up to 98%; the permeare flux of RO could be up to original flux after using 0.2%HCl (pH＞2) cyclic wash.The results of the test on treatment of circulating cooling water show that, when treat 4% circulating cooling water, the maintained cooling water pH is 7.3, the average total hardness is 135.33mg/L, and the average total alkalinity 76.46mg/L, which are less than standard level of JRA, and the water quality can stay a low rage after long-term operation, it satisfies the test requirement; After amplification calculation on the above experiment and a system of circulating cooling water which quantity of circulating Water is 900m~3/d, the cost of UF-RO on treatment of circulating cooling water is 1.64 yuan/t, the methods are of some value in economic and social benefits.