Study Of Mechanism Of Combined Removal Of So₂ And No From The Flue Gas By Activated Coke

As the major air pollutants, SO2 and NOx emission was intensified, they result in significant harm of acid rain. Damage caused by air pollution account for about 2%-3% of China's GDP per year. Coal-fired power plants are a major source of SO2 in the atmosphere, reducing power plant emissions of SO2 and NOx is of great significance on the control of air pollution.Activated coke with good pore structure, the more developed surface area and rich surface groups and renewable is one of the excellent adsorbents. The activated coke joint flue gas desulfurization and denitration technology is widespread concerned. In this paper, the mechanism of removal of SO2 and NO by activated coke, as well as interaction effects about SO2, NO, and NH3 were studied. The the removal behavior and the mechanism of activated coke desulfurization and denitrification were discussed. Study of process of the desulfurization reactor removal the SO2 by activated coke is carried out, that examined the factors impact of combined removal and provided a theoretical basis for industrial applications.In this paper, the activated coke made of the Tai Xi anthracite, which contains more advanced micro and medium hole, the surface of activated coke richer alcohols, carboxylic acids, phenols, quinones and other oxygen-containing functional groups from the domainπelectrons as well as the pyridine class, pyrone, class pyran-functional such as nitrogen groups. After the adsorption of NH3 activated coke can increase the surface N-containing functional groups.It is studied and found that in the process of activated coke desulfurization, when the flue gas without O2 and H2O, the SO2 adsorption is physical adsorption and the capacity is very small. When the flue gas contain O2, the SO2 adsorption on the surface of the activated coke, including both of physical adsorption and chemical adsorption. SO2 first adsorbed to the surface of activated coke and was oxidized SO3 by gaseous O2, increase the amount of SO2 adsorption. The SO3 generated is occupying active sites, since there is no H2O, failed to produce H2SO4 and vacant active sites, The SO2 removal rate is small. The O2 and H2O exist in flue gas, in the SO2 removal process by activated coke, H2O not only as a solvent of SO3, but also on the role of the nitrogen-containing groups of surface of activated coke, O2 and H2O reacted, which increased alkaline of coke surface and enhanced the SO2 adsorption and oxidation. It is greatly promote the removal of SO2. The SO2 adsorption capacity is the largest.In the process of activated coke ammonia selective catalytic Removal of NO, NH3 and O2 are obviously promote the removal of NO and H2O inhibit it in flue gas.NH3 belonging to polar molecules and the adsorption much larger than the NO on the surface of activated coke, NO adsorption is weak. As the NH3 adsorption on the surface of activated coke increased, NO removal rate is also increased. The activated coke ammonia-selective catalytic reduction NO(SCR) reaction occurred between the gaseous NO (or weakly adsorbed) and the adsorbed NH3, in line with Eley-Rideal mechanism.SO2 and NO on the surface of activated coke is competitive adsorption, SO2 absorption is stronger than NO, and exchange out of the NO physical adsorption. Chemical adsorption of NO on the adsorption of SO2 has a facilitating role. Activated coke adsorption of NH3, can promote the removal of SO2, NH3 not only reacted with SO2, which can also adsorbed on the activated coke and formed on the surface of the nitrogen-containing basic functional groups, that promote the adsorption and catalytic oxidation of SO2. Gasous NH3 can promote the removal of SO2 and NO at the same time, SO2 removal is greater.Experimental simulation of the joint removal of activated coke in the desulfurization process reactor, at this time, the activated coke from the denitration reactor and adsorped some NH3, the flue gas contain SO2 and NO. It is study that, the lower SO2 concentration, the smaller the airspeed and low-temperature are more conducive to the removal of SO2, NO is no bad effect on the removal of SO2.