Investigation Of Flow Field Uniformity For The Spray Tower In A Wet Flue Gas Desulfurization System

ABSTRACT:Limestone/gypsum wet flue gas desulfurization (WFGD) is the most important way for desulfurization in power plant, but when the WFGD system is in operation it will carry slurry out of the tower with the smoke, which causes "gypsum rain" and other damages. The reason of the serous slurry entrainment is the uneven distribution of the smoke in the desulfurization tower. This work studied the characteristic and the uniformity of internal flow field of the desulfurization tower.First of all, in order to simulate the influence of demister in flow field, the resistance of demister is studied using the commercially available software Fluent. The study focuses on the amount of serous entrainment and the flue gas flow rate. The relationship of pressure drop with the change of velocity in the demister is determined and can be used to simulate the influence of demister to the flow field of the desulfurization tower. The results showed that:(1) the slurry entrainment has little effect on the pressure drop of the demister, which can be ignored;(2) the pressure drop will increase when the flue gas velocity increases.Then, an experimental system was set up according to the similarity criterion of fluid mechanics. The influences of demister and the slurry spray to the flow field of the desulfurization tower are studied experimentally. The results show that:(1) the demister has a strong integration function on the flow field around it, and cannot be ignored in the simulation;(2) the slurry spray has a strong influence on the flow field in the reaction area, and cannot be ignored in the simulation.Finally, the internal flow field of the desulfurization tower is studied using the Fluent, and the simulation results were verified by experiments. The results showed that:(1) the porous jump model and DPM model can be used to simulate the flow field of desulfurization tower;(2) the demister has a great influence to the flow field of the desulfurization tower, and cannot be ignored in simulation;(3) the slurry influences the flow field a lot, and spraying upward is conducive to the uniform of flow field, at the same time do little to the resistance of the tower;(4) heightening the tower body is better for the uniform of the flow field near the demister, which is also good for demisting;(5) changing the outlet of flue gas from the side to the roof of the desulfarization tower, has no role of uniforming the flow field, but increases the resistance in desulfurization tower which is not conducive to the operation of the desulfurization tower.