| With an emission standard of air pollutants for coal-fired power plants increasingstringency, the improvement of desulfurization technology has become a burning issue whichbrooks no delay. Limestone (calcium oxide)-gypsum wet flue gas desulfurization (WFGD) isthe most widely used by coal-fired power plants, it’s core equipment is desulfurizationabsorption tower. The spray tower is the most common type of desulfurization absorptiontower in China, which are characterized by easy maintenance, stable operation and highefficiency. Owing to lack of foreign technology digestion, problems of nozzle atomizing andinterior architectural design were studied and studied, improving design scheme was putforward according to existing problems.On the premise of high desulfurization efficiency, we should count the cost and Reliableoperation in spray tower structure optimization. The optimum design of the spray tower indesulfurization unit includes two main aspects: the selection of nozzles and the layout ofpipeline networks.Limestone slurry exists in the shape of droplets in spray absorbers, which reacts withsulfur dioxide in the flue gas. Droplets are represented as typical chemical mass transferreaction zone. So we can lessen the gas-liquid mass transfer resistance in order to promote thereactions sulfur dioxide absorption reaction. The study of droplets has established atheoretical analyzing model on the basis of two-film mass transfer theory. Simulation resultsdemonstrate that mass transfer resistance can be trimmed to reduce the droplet diameter in theliquid film and film, the residence time of the droplets in the tower will be increased, Thedesulfurization efficiency of spray absorber will be effectively improved and the suitablediameter of the droplets between170μm and1500μm.Due to the difficulty in finding an atomizing nozzle that presents the above-mentioneddiameter of the droplets, a gas-outside liquid-inside atomizer with a built-in Rafael air nozzleis designed based on the atomisation mechanism of two-fluid air blast atomizer. Theexperimental performance of the atomizer show that the diameter of droplets will below250μm when the pressure of the gas and liquid is less than0.5MPa, the spray angle of nozzlebetween40°and90°, the relation between the air-liquid mass rate and the liquid-air pressureratio can be represented by a simple little equation: Pli/Pai=0.04552w-1.04888and the criticalair-liquid mass rate is found to be0.057.Aiming at the subsistent problems in WFGD, this paper proposes a Spray Toweroptimum structural design idea Used Gas-Oueside Liquid-Inside Atomizer, and gives a whole design plan following the structural parameters and performance parameters of a coal-firedpower plant.In order to reduce the pressure loss of the spray layer to take on the appearance ofherringbone structure, the branch pipe are arranged by wing with an equally distant from thetower wall. The main gas pipe having a direction opposite to the main slurry pipe to savespace. The spray angle (52°), volume flow (73.077m3/h) is determined by the spraycharacteristics by atomizer, and the diameter of gas pipe and slurry pipe are given byprocedure data.The performance experiment for spray tower draw some conclusions: The new freshair which are driven into spray tower by new fan has no effect on desulfurization efficiency;The flow and velocity of gas have approximative influence on desulfurization efficiency；thePH of slurry is an important parameter to desulfurization efficiency, and there is anapproximate linear relationship as η=0.398+0.819pH between them under the constant testconditions. |
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