Numerical Analysis Of Flow Field To Sintering Flue Gas Desulfurization System And Experimental Study

SO₂ emitted from iron and steel industry is about 8% of the total industrial emission in China. The iron and steel industry has become the second SO₂ emitting source, in which the sintering section of iron and steel production contributes to about 40-60% SO₂. So it is important to control SO₂ emission in the sintering process for total of SO₂ reduction.The process of Sintering gas desulfurization just began a few years ago in China. Due to the wide range of gas temperature , large gas volume, wide range of concentration of SO₂,frequently start and stop of sintering equipment,the best choice of the sintering gas desulfurization technology is being discussed. A Chinese iron and steel company applied the NID (Novel Integrated Desulfurization) technology from Alstom Company. Because of the variability of sintering gas characteristic, the flow field and the desulfurization operating parameters should be studied.In this paper, the fluid dynamics of the NID system was studied by using Fluent, considered the influence of gas volume, pressure jump of fan after the bag house and outlet pressure on the gas volume of the bypass. The study showed that pressure jump of fan after the bag house became the main factor in affecting the volume of bypass, and the most economical gas volume of bypass is about 10% of the inlet gas amount. Finally, a cold 20:1 model of NID system was build to verify the simulation result.In this paper, the preparation of desulfurization material has also been studied. The influence of H2O/CaO ratio, initial water temperature, stirring rate on the BET surface area of Ca(OH)2 was considered. Finally, the best way to prepare Ca(OH)₂ was obtained. At last, an entrained flow bed desulfurization system which handled 25m³/h gas was established. It included gas pre-heating system, reaction system, bag house, humidification system, feeding system, gas flowing system and control system. The influence of gas temperature, Ca(OH)2 humidity on SO₂ removal efficiency, reaction rate, and the desulfurization efficiency under different circulation ratios was studied based on this system. The result showed that the desulfurization efficiency reaches as high as 90% even at the temperature less than 373K.