Study On Humidification Of The Flue Gas Desulfurization In Dense Phase Tower System

The pollution of SO2and the acid rain in our country has become more and moreserious, and the task of SO2emission reduction in sintering flue gas of major steelcompanies is arduous during the period of12th Five-Year Plan. At present, for FGDtechniques having some problems in treating sintering flue gas effectively, it is emergentto develop new desulfurization technology. As a kind of semi-dry flue gas desulfurizationtechnology, dense phase tower system has widely used in sintering flue gasdesulfurization. In recent years, due to the advantages of semi-dry desulfurizationprocess, such as the advanced design, low cost and stable operation, it has attracted muchmore attention. This paper mainly does some research on the humidification of theprocess.Based on the analysis of the effect of wet digestion time, cement water ratio, stirringspeed, the best wet digestion conditions are determined; and the wet digestion method ofash circulation are also determined. The optimal humidification conditions are alsoachieved by the analysis of the thermodynamic characteristic of circulating ash of thedigestive process. The characteristics of different humidifying equipment are alsostudied.Under the optimum wet digestion conditions, the digestion time is20min thestirring speed is100r/min; When the cement water ratio is2g/ml, lime conversion rate is97.84%, the moisture content is3.98%, and specific surface area is5.231m2/cm3withhigh desulfurization efficiency, high specific surface area, and great humidifying effect.The results showed that, with the increase of cycle times, the best cement-waterratio of the selected different loop nodes are4g/ml4g/ml5g/ml and7g/ml respectively，and transformation rate of quicklime can reach88.13%95.21%96.75%and93.45%,product moisture content are3.75%4.32%5.31%and4.23%. With the bestcement-water ratio, the cycling ash transformation is high, and humidification effect isgood. After the cycle to40%, reduce the adding speed of water can achieve precise controlcycling ash humidification. And the steam appeared in the late cycle is more useful fordesulfurization reaction.The results of thermodynamic calculation of wet digestion for circulating ashshowed that, compared with the condition without any humidification, the water additioncan significantly improve the rate of desulfurization. Steam is more effective than liquidwater for the desulfurization reaction in the middle and later period of wet digestion.