Research Of Industrial Flue Gas Desulfurization By Alumina Red Mud

The power industry in China grows steady and fast with the rapid development of economy. Electric power industry is one of the biggest coal consumers which the thermal power generation accounts for about80%. A large number of SO2emissions are resulted from coal combustion, which will cause serious threat to human health, the natural environment, industrial and agricultural production, architectural materials and so on. Flue Gas Desulfurization (FGD) has been the main controlling means of SO2emissions. But the high cost of current flue gas desulfurization technologies is still problematic. Red mud from alumina industry is high alkaline solid waste. which is discharged about0.8-1.5t per ton alumina production. Red mud discharged annually in China is more than30million tons recent years that bring serious social, ecological, environmental and economic problems and the sustainable development of alumina industry has been seriously hindered.This research comes from the Sub-Project of2010Henan Big Commonweal Research Project:"Technological Research of Industrial Flue Gas Desulfurization by Alumina Red Mud", which aims to making two originally environmental pollutants interaction. SO2in flue gas was removed and alumina red mud can be utilized comprehensively as well.First, the mineral composition, chemical composition, grain size, microstructure, and reaction activity of alumina red mud were analyzed and acid-insoluble components in the red mud were determined. Thermodynamics analysis of FGD related major chemical reactions was studied. The result showed that industrial flue gas desulfurization was feasible theoretically. Morever, the basic principle of red mud desulfurization in gas-liquid-solid three phases was analyzed systematically using "Double Film Theory"Second,1700X60mm small glass tower absorption device was designed and installed. Based on the selection of equipments and accessories related to desulfurization system such as slurry circulating pump, centrifugal air compressor, liquid and gas flow meters, pipe valves and so on, flue gas from2#Booster fan of1# Generating Set was introduced into the laboratory on-the-spot of Zhengzhou Xinli Electric Power Company. Cyclic absorption experiments were conducted and the influential factors such as liquid solid ratio, empty tower gas velocity, SO2concentration, liquid gas ratio were examined through the orthogonal tests. The influential factors remarkable sequence is liquid gas ratio>liquid solid ratio>empty tower gas velocity> SO2concentration. The optimum conditions are:liquid-solid ratio7/1(mass ratio), gas flow0.35m/s, liquid-gas ratio12/1(L/m3), concentration of SO21700mg/m3. Under the optimum conditions, SO2absorption ratio reached97.5%.Finally, the desulfurization effect in this process was compared with the traditional limestone-gypsum method under the same experimental conditions. The result showed that the alumina red mud desulfurization is better than the limestone method.