高浓度CO2气氛下燃煤氮、硫污染物的释放特性

采用污染物在线分析仪、气相便携红外分析仪研究了程序升温条件下改变氧化介质时煤中氮,硫的释放特性以及含硫物相的浓度变化规律,探讨了不同气氛,CO2浓度与O2浓度单独变化时对NO、SO2析出特性的影响机理.结果表明:O2/CO2燃烧气氛下NO、SO2排放峰值及总量均低于O2/N2气氛.CO2气氛下烟气中存在大量的CO,有利于NO的降解,同时也促进了烟气中其他含硫物相的形成,随着CO2浓度的增加,特别是在燃烧后期,NO、SO2的排放显著降低.O2浓度改变对NO和SO2的释放影响不同:O2浓度升高促进了SO2的析出;但是O2浓度在一定范围内增加对NO的排放并无明显影响,随着O2浓度进一步增加,NO的释放峰向低温区迁移,同时排放量降低.

RELEASE OF NO AND SO2 IN HIGH-CONCENTRATION CO2 ATMOSPHERE DURING COAL COMBUSTION

The release of S,N and the formation of other S-species have been investigated in a programmed-temperature horizontal tube furnace by means of pollutants on-line analyzer and portable infrared gaseous analyzer when changing combustion medium.The effects of atmosphere,CO_2 and O_2 concentrations on the emission of NO and SO_2 were discussed.The results showed that both the emission amount and peak value,of NO,SO_2 decreased in O_2/CO_2 atmosphere in contrast to that of O_2/N_2 atmosphere.The concentration of CO increased during O_2/CO_2 atmosphere,which is favorable for NO reduction and other sulfureous phase formation in flue gas.With the increase of CO_2 concentration,the emissions of NO and SO_2 reduced significantly,especially in the later stage of coal combustion.The effect of O_2 concentration on the emission of NO and SO_2 is different:SO_2 emission was promoted when increasing O_2 concentration,while there is no significant impact on NO emission when O_2 concentration changed in a certain range,as the O_2 concentration increased further,the peak temperature of NO emission dropped and the emission amount decreased.