Research On Desulfurization Wastewater Treatment Of Coal-fired Power Plant Based On The Coupling Process Of Microfiltration And Flue Evaporation

As environmental protection policies become more and more stringent,traditional desulfurization wastewater treatment processes will be difficult to meet environmental protection requirements.The treatment of desulfurization wastewater from coal-fired power plants is moving in the direction of "zero discharge”.One is that it has unparalleled advantages over other processes in terms of investment and operating costs,and it has been applied in many domestic power plant projects.However,this process generally has problems such as nozzle clogging and incomplete droplet evaporation.In response to the existing problems,this paper proposes to use flat ceramic membranes to filter wastewater.The purpose is to remove suspended solids in the wastewater and prevent nozzle clogging.At the same time,numerical simulation is used.The evaporation process of waste water droplets in the flue is studied,and the influence of each key factor on the droplet evaporation characteristics is explored,so as to provide theoretical support and data reference for the improvement of the process in engineering applications.In the first part of this paper,a flat ceramic membrane is used to filter the desulfurization wastewater,and the influence of factors such as transmembrane pressure difference,aeration and backwashing on the permeability of the membrane is explored.Secondly,the water quality before and after filtration and the pollution of the membrane are tested and analyzed.The experimental results show that under constant pressure operation,the membrane flux of the flat ceramic membrane decreases rapidly first,then decreases steadily,and finally stabilizes;compared with the backwash time,the influence of the backwash pressure on the membrane flux is more obvious.When the backwash interval is 2 min,the backwash pressure is 0.01 MPa,and the backwash time is 5 s,the net water production per unit time of the microfiltration system is the highest,525 L·h-1m-2;the 1 μm plate ceramic used in the experiment The membrane can effectively remove the suspended matter in the desulfurization wastewater,and meet the inlet water quality requirements of the two-fluid nozzle in the flue evaporation process(suspended matter content<500 mg/L);after scanning electron microscope(SEM)and energy dispersive X-ray spectrum analysis(EDS),it proves that backwashing can effectively suppress the pollution problem of the membrane,and at the same time,it was judged that the contaminants on the membrane surface were inorganic substances mainly composed of calcium compounds.The second part of this paper uses Fluent software to simulate the evaporation process of desulfurization wastewater flue,and explores the characteristics of droplet evaporation by flue gas velocity,flue gas temperature,droplet diameter,droplet velocity,spray angle,and spray flow rate.Impact.The results show that the evaporation time and evaporation distance of the atomized droplets in the flue are mainly related to the temperature of the flue gas at the tail of the boiler,the flow rate of the flue gas,the diameter of the atomized droplets,the spray flow rate and the spray angle,and the initial velocity of the waste water droplets and the nozzle position It has little effect on the evaporation process;in the flue evaporation process,the maximum evaporation of waste water is limited by the outlet flue temperature and the length of the flue.When the flue temperature is low,the maximum evaporation is determined by the outlet flue temperature.When it is high,the maximum evaporation is determined by the length of the flue.Finally,the experiment and simulation part of this article are summarized and analyzed,and relevant suggestions on the research of the coupling process of microfiltration and flue evaporation are put forward.