Research On Treatment And Reuse Of Desulfurization Wastewater In Coal-fired Power Plant

At present,the domestic large capacity coal-fired power generating units are equipped with wet flue gas desulfurization,wet desulfurization process will produce large amounts of wastewater.It is necessary to make the research and devel opment of the comprehensive wastewater reuse technology,and to evaluate its practical application effect.Combined with the current situation of the application of desulfurization wastewater reuse technology and the results of wastewater quality analysis,the author carried out three series of experimental research on pretreatment,membrane concentration and evaporation crystallization under the wet desulfurization conditions.In the practice power plant,the author carried out pretreatment + gypsum crystal study on desulfurization wastewater by MVR evaporation crystallization.By comparing the screening showed that the plant desulfurization waste water adding amount of Ca(OH)2 and Na2SO4,followed by 13.7g/L?6g/L,concentrations and the p H reach 12.5,treated water quality accords with gypsum seed crystal method evaporation crystallization water quality requirements;DTRO(disc-type reverse osmosis)operating pressure is higher,under the operating pressure of 75 bar,the TDS of concentrated water can reach 100000mg/L,the TDS of water production reached 1200-1300 mg/L.In the experiment of pretreatment + gypsum seeding method MVR evaporation crystallization process,the feasibility of gypsum seeding MVR evaporation crystallization process for desulfurization wastewater was verified.In "legs with salt washing + outer row of mother liquor of coordinating role",the separation of the effluent gypsum and the sodium chloride salt can be achieved.The outer row of crystalline salt(sodium chloride)is pure white crystal,the indicators meet the refining industrial salt standard grade gifted,the secondary effluent discharge meet the re-use standards.According to the reduction process route selection,according to different engineering requirements,the appropriate treatment process can be selected to achieve a large number of wastewater reuse,less emissions or zero emissions.Desulfurization wastewater reuse technology has a very broad application prospects in coal-fired power plants and coal chemical industry.In the evaporation crystallization process,should be in-depth research crystallization salt purification technology,can be sold as industrial salt,will significantly enhance the economic benefits of technology.Economic and reliable wastewater reuse proc ess is conducive to industrial wastewater treatment,but also produce better environmental benefits,economic benefits and social benefits.