| The method of limestone-gypsum wet flue gas desulfurization is the most widelyused method among desulfurization systems. But the system would produce a certainamout of desulfurization wastewater during working. Among all of the desulfurizationwastewater treatment methods, the physical-chemical treatment, which is usedcommonly has many drawbacks. For example, it is unable to remove chlorine ion. Byusing the atomizing nozzle, the desulfurzation wastewater is sprayed into flue gas ductbetween the air preheater and the electrostatic precipitator. Through technique ofevaporation by flue gas, solid particles can be dryed from wastewater. In this way, thedesulfutization wastewater can be treated well. But this process system is seldom usedbecause desulfurization wastewater in the flue gas is hard to evaporate completely,which is easily to cause corrosion of the precipitator. There in no power plant in thedomestic using this solution, and few power plant abroad use it.In this paper, a power plant in China is regard as the research background. Thecommerical CFD software, FLUENT, is adopted to study the evaporation process ofdroplet in the flue gas. The mathematic modle of motion and evaporation of droplet isestablished. Study on the effects of various parameters on desulfurization wastewaterevaporation characteristics was carried out.The parameters are flue structure, flue gastemperature, spray particle siza, the installation position of nozzle and so on.The dropletevaporation state under various conditions is obtained.This paper makes an analysis to the amout of unevaporated liqulid under thecondition of different droplet diameters and different flue gas temperatures andcorresponding calculation formula has been built.Through simulaiton, the following results are obtained. The length of straight ductis unable to evaporate desulfurization wastewater, and the length of bend flue can meetthe requirement. The higher the temperature of the flue gas is, the less the evaporationtime is, and the evaporating length is shorter. Besides, when the nozzles are installed indifferent distances to duct wall, it has little influence on wastewater evaporation. Thesimulation of CFD proves that the of the desulfurization wastewater evaporation systemis feasible. Proper diameter of the droplet was found, so was the position of nozzlesinstalled. As the feasibility of the system is proved, according to the specific circumstancesof the plant, a desulfurization wastewater evaporation system was designed. This systemconsists of five parts including wastewater transport system, air transport system, cleanwater transport system, spray nozzle and logic control system. By using the logiccontrol system, the remote control operation can be realized. At the same time, the typeselection of main equipment is determined.After the system was set up, experimental study is carred out in the power plant.Measurement parameters of desulfurization system and electrostatic precipitator arecollected. The paremeters when wastewater treament system is running are comparedwith that system not running. Besides, the infuence of the wastewater treament systemon desulfurization system and precipitator is studied. The results show that thedesulfurization wastewater treatment sysytem has not adverse effect on the operatingthe desulfurization system and precipitator of the power plant. |
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