Study On Removal Of Sulfur Dioxide And Nitric Oxides From Flue Gas By Activated Coke

SO2, NO and other atmospheric pollutants in industrial flue gas emissions are the primary cause caused by the atmospheric pollution, especially the acid rain and smog formed by SO2, NO are relating to majority of human health. Therefore, in order to solve the increasingly serious environmental problems, it is necessary to control and management of industrial gas as soon as we can. But how to efficiently and economical eliminate SO2and NO is still a worldwide problem, at present, desulfurization and denitration technology are mature and has succeeded in industrial application. The desulfurization technology were classified by desulfurization agent mainly have the wet, dry, semi-dry desulfurization technology, the denitrification technology is mostly established after desulfurization technology. SCR (selective catalytic reduction of NOx with NH3) which builds on the dry desulfurization technology is the mainstream technology. The dry denitrification technology is considered as the most potential technology in the purification technology, due to the well-known reasons such as high purification efficiency, low energy consumption, small occupation of land, no pollutions, convenient operation and so on.Dry desulfurization agent mainly have activated carbon and activated coke, the purifying material of activated carbon (coke) has obvious advantages in industrial flue gas desulfurization and denitration, such as removal of pollutants, low reaction temperature, small occupation of land. Besides, the sulfur and nitrate resources can be reused by activated carbon (coke) desulfurization. At present, the activated carbon and activated coke have been used in the developed countries, however, the equipment investment and purification of activated carbon and activated coke technology are too high. The active coke also have these characteristics such as large specific surface area, with abundant of pore structure and a lot of hydrogen oxygen elements. To sum up, it can be provide favorable conditions for desulfurization and denitrification, The more important reason is activated coke is cheaper than the active carbon. Due to the cause of our country, we should promote the application of active coke to denitration and desulfurization in china. Therefore, based on the previous research work, we used the activated coke instead of activated carbon materials for desulfurization and denitrification experiment, in order to obtain some new and meaningful results. The main research work and results are followed as:This paper introduces the research background and current situation of desulfurization and denitration technology. The significance of the study was discussed and we did experimental research and analysis on the desulfurization and denitration.In this paper, a lot of activated coke was prepared from Shanxi JinCheng anthracite and Eastern of Yunnan Lignite, the preparation process includes grinding, screening, carbonization, activation and so on. The study of desulfurization experiment were carred out with the simulated flue gas, then we investigate the desulfurization efficiency of the homemade activated coke (ACa, ACL) and commercial activated coke (RAW-AC). The research results showed that the desulfurization efficiency and sulfur capacity of ACa and ACL was lower than RAW-AC, in the range of100min, the desulfurization efficiency of RAW-AC was higher than55%.The best desulfurization agent was screened by preliminary experiment, we select the RAW-AC for subsequent experiments. The performance and feasibility of the activated coke for desulfurization and denitrification was improved by modification again. The study of desulfurization experiment was carried out with the simulated flue gas. The research results showed that the desulfurization efficiency of RAW-AC which treatment by KOH was improved again. Besides, literature data shows that the treatment of KOH was propitious to load a lot of metallic oxide on the activated coke.In this paper, in order to further improve the feasibility and performance of desulfurization agent. We loaded different metal oxides (Fe2O3, CuO, MnO2, CoO) and rare earth elements (Ce, La) on the RAW-AC and carried out the results in a fixed bed quartz tube reactor with simulated flue gas. The results shows that in the conditions:2000ppm SO2;5%O2, space velocity8000h1, reaction temperature120℃, the Fe/ACKoH and Ce/ACKOH have the best desulfurization efficiency. In the conditions:1000ppm NO;5%O2; space velocity8000h-1; reaction temperature80℃, the Cu/ACKOH and Ce/ACKOH have the best denitrification efficiency.By the experimental investigation, we studied the simultaneous of desulfurization and denitrification by Fe/ACKOH and Cu/ACKOH-The results show that the Cu/ACKOH have better simultaneous of desulfurization and denitrification efficiency. In the conditions:flow rate200ml/min;2000ppm SO2;1000ppm NO;5%O2; space velocity4000h-1, reaction temperature120℃, the desulfurization efficiency of both Fe/ACKOH and Cu/ACKOH remained99%in100min, the denitrification efficiency remained40%in45min. According to the literature data that the existence of NO could promot the desulfurization efficiency, but the existence of SO2could inhibited the denitrification efficiency.This paper adopt thermal desorption and ultrasonic water-washing regeneration to regenerate the activated coke which lost activity. The study results show that the regenerated activated coke (Fe/ACKOH and Cu/ACKOH) had lower removal efficiency and keep the desulfurization and denitration rules. In100min, the removal SO2efficiency of Fc/ACKOH which regenerated by ultrasonic water-washing remained95%and Cu/ACKOH remained92%, the removal NO efficiency of Fe/ACKOH and Cu/ACKOH remained above35%. In a word, the ultrasonic water-washing was better than thermal desorption.