Study On Flue Gas Desulphurization By Modified Activated Coke

China is one of the largest countries using coal as the chief energy sources, whose energy resources are rich in coal but lacking in petroleum and natural gas. The characteristics of the country’s energy sources result that the energy problem must be solved based on coal. In the process of exploitation and utilization of coal resources, the problem of environmental pollution from burning coal has been deteriorating, which severely restricts the sustainable development of our country’s economic and society. Flue gas desulfurization by activated coke is a kind of advanced dry desulfurization technology. It can overcome the shortcomings of large water consumption, secondary pollution and so on, which exist widely in limestone/gypsum flue gas desulphurization. Meanwhile, it can recover the sulfur resources and effectively reduce other pollutants. The kind of dry desulfurization technology is more applicable for the west regions where coal is rich but water is lacking.The desulfurization by activated coke was investigated on a fixed bed reactor. Comparation was made between the commercial and experiment activated cokes in the performance of desulfurization and regeneration. Research was made on the influence of processing parameters and modification methods on the desulphurization performance of WLS-AC. The desulfurization kinetics was also investigated. The physical and chemical properties of activated coke were characterized by acid-base titration, N2adsorption, X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectroscopy (FT-IR) and so on. The results are as follows:1. The comparison of four raw materials of activated cokes on SO2removal efficiency shows that:WLS-AC>IM-AC>SM-AC>BX-AC. The desulfurization and regeneration performance of WLS-AC were better than commercial XH-AC. On the consideration of the cost, the direct heating regeneration method was preferred. The pore structure of activated coke influenced desulphurization performance, but was not the decisive factor. The desulfurization of activated coke was strongly influenced by its surface chemical properties and associated with basic C=O groups.2. The optimum process parameters were:particle size of activated coke40-60meshes, GHSV=1000-2000h-1, T=100℃, simulated flue gas composition SO2500-1000ppm, O26%, H2O10%.3. The modification of WLS-AC:(1)The desulfurization perform-ance of activated coke was increased after deashing. The activated coke from acid deashing was better than acid&alkali deashing.(2)The iodine adsorption value and surface basic group were increased as well as the desulfurization performance after HNO3modification. The proper HNO3modification conditions were:concentration of nitric acid15%-30%, activation time90min, activation temperature100℃, calcining temperature500℃.(3)Modification by impregnating aluminum nitrate and copper nitrate showed the best sulfur capacity effect and sulfur capacity was increased by>40%.4. According to the deceleration phase fitting of adsorptive reactions, adsorption rate equation and the parameters were obtained. The results of experiment show that the adsorption rate constant increased first and then decreased with temperature from60℃to140℃. Higher temperature was unfavorable to SO2removal efficiency.