烧结烟气的循环流化床焚烧处理方法  

Circulating fluidized bed incineration treatment of sintering flue gas

作　　者：沈宇帆 韩诚良 柯希玮 张扬[1,2,3] 张杨鑫 张海 吕俊复[1,2,3] SHEN Yufan;HAN Chengliang;KE Xiwei;ZHANG Yang;ZHANG Yangxin;ZHANG Hai;LYU Junfu(Key Laboratory of Thermal Science and Power Engineering,Ministry of Education,Department of Energy and Power Engineering,Tsinghua University,Beijing100084,China;Beijing Huairou Laboratory,Beijing 101499,China;Shanxi Research Institute of Huairou Laboratory,Taiyuan 030032,China;Shanxi Clean Energy Research Institute,Tsinghua University,Taiyuan 030032,China)

机构地区：[1]清华大学能源与动力工程系热科学与动力工程教育部重点实验室,北京100084 [2]北京怀柔实验室,北京101499 [3]怀柔实验室山西研究院,山西太原030032 [4]清华大学山西清洁能源研究院,山西太原030032

出　　处：《煤炭学报》2024年第10期4051-4059,共9页Journal of China Coal Society

基　　金：太原市关键核心技术攻关“揭榜挂帅”资助项目(2024TYJB0101);清华大学山西清洁能源研究院“揭榜挂帅”资助项目(2023JZ0501001);怀柔实验室重大专项资助项目。

摘　　要：烧结烟气是钢铁生产的烧结工序产生的废气,含NO_(x)、SO_(2)、二噁英、挥发性有机物等污染物成分。用烧结烟气替代燃煤循环流化床锅炉空气以焚烧处理,既能有效资源化利用废气中CO和余氧,又能借助循环流化床中脱硫脱硝设备与高温环境,将烧结烟气中SO_(x)和NO_(x)等污染物与燃煤产生的污染物一并去除,有望成为高效的烧结烟气一体化污染物处理技术。然而,目前燃煤循环流化床燃烧背景下烧结烟气中二噁英、挥发性有机物等污染物脱除的研究尚不足。针对该问题,先通过化学反应动力学模拟,研究烧结烟气作为助燃剂燃烧过程,发现燃烧过程中产生的氢等自由基在二噁英分解过程中发挥重要作用,燃烧反应温度提高能显著促进二噁英及挥发性有机物的脱除,而燃尽烟气的余氧量降低对二噁英的脱除也有较显著促进作用。通过计算颗粒流体动力学的方法,模拟以烧结烟气为助燃剂的燃煤循环流化床锅炉运行情况,发现燃烧过程流态化情况好,烧结烟气中低浓度CO基本燃尽,旋风分离器出口CO质量浓度约100 mg/m^(3),燃烧温度达到去除污染物的要求,验证了将烧结烟气作为燃煤循环流化床锅炉中助燃剂的可行性。在唐山某钢铁企业开展了烧结烟气的循环流化床焚烧方法工程验证,测试发现低低温省煤器出口处烟气二噁英脱除率超过99.5%,低至0.0057 ng TEQ/m^(3),CO质量浓度低至108 mg/m^(3),此外烟气中NOx和SO2质量浓度低至38、24 mg/m^(3),满足超低排放要求。工程验证证实循环流化床烧结烟气一体化焚烧处理技术有效。Sintering flue gas is the waste gas produced in the sintering process of steel production,containing NO_(x),SO_(2),dioxins,volatile organic compounds,and other pollutants.The sintering flue gas can replace the air of the coal-burning circulating fluidized bed(CFB)boiler for incineration treatment,which can effectively reuse CO and residual oxygen in the waste gas,and remove SO_(x),NO_(x),and other pollutants in the sintering flue gas together with pollutants from coal combustion by the high-temperature atmosphere and desulfurization and denitrification facilities in the CFB boiler.It is expected to become an efficient integrated treatment technology for sintering flue gas.However,the research on removing dioxins and volatile organic compounds from sintering flue gas by coal-fired circulating fluidized bed boilers is still limited.The coal combustion process of sintering flue gas as an accelerant was studied through chemical reaction kinetics simulation.It is found that hydrogen radicals and other free radicals produced in the combustion process are the main mechanisms of di-oxin removal,and the increase in combustion reaction temperature can significantly promote the removal of dioxins and volatile organic compounds.The decrease of residual oxygen in burned flue gas can also encourage the removal of diox-ins.The operation of a coal-fired CFB boiler with sintering flue gas as the accelerant is simulated by calculating particle fluid dynamics.It is found that the fluidized state of the combustion process is good,and the low-concentration CO in the sintering flue gas is burned out with the cyclone separator outlet mass concentration of CO at around 100 mg/m^(3).The combustion temperature also satisfies the temperature requirement for removing pollutants.The feasibility of using sinter-ing flue gas as the accelerant in the coal-fired CFB boiler is verified.The engineering verification of the CFB incineration method for sintering flue gas is conducted in a steel plant in Tangshan.The test on the flue gas at the outlet

关 键 词：循环流化床 烧结烟气 焚烧处理 二噁英 污染物治理 

分 类 号：TQ536[化学工程—煤化学工程]