• 关键词：CO₂  污泥  Fuel-N  析出特性

• 基金项目：国家自然科学基金（No.NSFC-51778264）；广州珠江科技新星项目（No.201610010150）；广东特支计划项目（No.2016TQ03Z576）；广东省科技项目（No.2017B020237002）；公益性科研院所基本科研业务专项（No.PM-zx703-201803-077）

• 肖香
• 环境保护部华南环境科学研究所, 广州 510655

• 方平
• 环境保护部华南环境科学研究所, 广州 510655

• 黄建航
• 环境保护部华南环境科学研究所, 广州 510655

• 唐子君
• 环境保护部华南环境科学研究所, 广州 510655

• 吴海文
• 环境保护部华南环境科学研究所, 广州 510655

• 岑超平
• 环境保护部华南环境科学研究所, 广州 510655

• 唐志雄
• 环境保护部华南环境科学研究所, 广州 510655

• 摘要：在模拟水泥分解炉气氛条件下，考察了CO₂浓度对污泥燃料N（Fuel-N）析出特性的影响，结果表明污泥Fuel-N的析出形式主要为NH₃、HCN及NO_x.在研究的CO₂浓度范围（体积分数0~35%）内，CO₂浓度的升高将消耗更多的含氮位点和H自由基，导致NH₃的析出受到抑制；而CO₂能直接氧化HCN或—CN官能团，导致HCN的析出随着CO₂浓度的升高逐渐降低.NO_x的析出量随CO₂含量的升高先减小后升高，在25%时达到最小值.NO_x的生成和还原反应是同步发生的，在燃烧温度和O₂含量一定的情况下，NO_x的析出主要受NO_x还原反应的影响，研究表明燃烧过程中同时存在NO_x的气相均相还原反应和气固异相还原反应.当CO₂浓度从0上升至25%时，CO₂分子与污泥焦反应生成的CO相对增加，在污泥焦表面的催化作用下，NO_x被CO还原的量增多，此时污泥焦对NO_x的气固异相还原占据主导地位；继续增加CO₂浓度至35%时，还原性气体HCN生成幅度下降较大，此时HCN、NH₃对NO_x的气气均相还原占据主导地位，导致NO_x的析出逐渐升高.

• Abstract：The effect of CO₂ content on the fuel-N release characteristics from sewage sludge combustion was investigated in simulated flue gas of cement precalciner. The experimental results showed that the emission forms of Fuel-N were mainly NH₃、HCN and NO_x. The increasing of CO₂ content consumed more nitrogen containing sites or H free radicals, resulting in the inhibition of NH₃ release. As CO₂ directly oxidized HCN or -CN functional groups, the amount of HCN release gradually decreased with the increasing of CO₂ content. The amount of NO_x decreased first and then increased as the CO₂ contents increased, with a minimum value at 25%. NO_x generation and reduction reactions occured synchronously, while the emission of NO_x was mainly affected by NO_x reduction under the condition of certain combustion temperature and O₂ content, the results showed that the homogeneous and heterogeneous reduction reaction of NO_x were both concurrence during combustion. With the increasing of CO₂ content from 0 to 25%, the CO generated by the reaction between CO₂ molecules and sludge char increased relatively, the amount of NO_x reduction by CO increased under the catalytic of sludge char surface, thus the sludge char played a leading role in the gas-solid heterogeneous reduction of NO_x. The generation of reducing gas HCN decreased significantly as continue increasing CO₂ concentration to 35%, and the gas-gas homogeneous reduction of NO_x by HCN and NH₃ was dominated, leading to the gradual increasement of NO_x emission.

• Key words：CO₂  sewage sludge  fuel-N  release characteristics

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