Operating condition influences on PCDD/Fs emissions from sinter pot tests with hot flue gas recycling  

作　　者：Yongmei Yu Minghui Zheng Xianwei Li Xiaolei He 

机构地区：[1]State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, P.O. Box 2871, Beijing 100085, China [2]Research Institute of Baoshan Iron & Steel Co., Ltd., Shanghai 201900, China

出　　处：《Journal of Environmental Sciences》2012年第5期875-881,共7页环境科学学报（英文版）

基　　金：supported by the National Basic Research Program (973) of China (No. 2009CB421606);the National Natural Science Foundation of China (No. 21037003,20921063);the National Key Technology R&D Program (No. 2008BAC32B05)

摘　　要：This study was designed to clarify the influence of operating conditions on the formation and emissions of polychlorinated-p-dibenzodioxins and dibenzofurans （PCDD/Fs） from a sintering process with hot flue gas recycling. A pilot scale sinter pot with simulated flue gas recycling was developed, and four key operational parameters, including temperature, oxygen content of the simulated waste flue gas, the coke rate of the sintering mixture, and the quicklime quality, were selected for exploring PCDD/Fs formation. The results showed that the temperature of the recycled flue gas had a major affect on PCDD/Fs formation, and a high temperature could significantly increase their formation during sintering. A clear linear correlation between the temperature of recycling flue gas and PCDD/Fs emission （r = 0.93） was found. PCDD/Fs could be reduced to a certain extent by decreasing the level of oxygen in the recycled flue gas, while sintering quality was unchanged. The coke rate had no significant influence on the formation of PCDD/Fs, but the quality of quicklime used in the sintering mixture could affect not only the amount of PCDD/Fs emissions but also the sintering productivity. Compared with a benchmark sinter pot test, PCDD/Fs emissions markedly decreased with improvements to quicklime quality. However, the reduction in PCDD/Fs emissions realized by using high-quality quicklime was limited by the temperature of the inlet gas. The highest reduction achieved was 51% compared with conventional quicklime when the temperature of the inlet gas was 150°C.This study was designed to clarify the influence of operating conditions on the formation and emissions of polychlorinated-p-dibenzodioxins and dibenzofurans （PCDD/Fs） from a sintering process with hot flue gas recycling. A pilot scale sinter pot with simulated flue gas recycling was developed, and four key operational parameters, including temperature, oxygen content of the simulated waste flue gas, the coke rate of the sintering mixture, and the quicklime quality, were selected for exploring PCDD/Fs formation. The results showed that the temperature of the recycled flue gas had a major affect on PCDD/Fs formation, and a high temperature could significantly increase their formation during sintering. A clear linear correlation between the temperature of recycling flue gas and PCDD/Fs emission （r = 0.93） was found. PCDD/Fs could be reduced to a certain extent by decreasing the level of oxygen in the recycled flue gas, while sintering quality was unchanged. The coke rate had no significant influence on the formation of PCDD/Fs, but the quality of quicklime used in the sintering mixture could affect not only the amount of PCDD/Fs emissions but also the sintering productivity. Compared with a benchmark sinter pot test, PCDD/Fs emissions markedly decreased with improvements to quicklime quality. However, the reduction in PCDD/Fs emissions realized by using high-quality quicklime was limited by the temperature of the inlet gas. The highest reduction achieved was 51% compared with conventional quicklime when the temperature of the inlet gas was 150°C.

关 键 词：PCDD/FS sintering recycling flue gas formation mechanism 

分 类 号：TF72[冶金工程—钢铁冶金] TS272.7[农业科学—茶叶生产加工]