Experiment and mechanism investigation on advanced reburning for NO(x) reduction: influence of CO and temperature.
Experiment and mechanism investigation on advanced reburning for NO(x) reduction: influence of CO and temperature.
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DOI：
10.1631/jzus.2005.b0187
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发表时间：
2005-03
期刊：
影响因子：
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通讯作者：
Zhi-hua Wang;Junhu Zhou;Yan-wei Zhang;Zhi-min Lu;Jianren Fan;K. Cen
中科院分区：
文献类型：
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作者：
Zhi-hua Wang;Junhu Zhou;Yan-wei Zhang;Zhi-min Lu;Jianren Fan;K. Cen
在中试实验台上对煤粉再燃、喷氨再燃和先进再燃进行了研究。将石油气、空气和NH3预混物在多孔气体燃烧器中燃烧以产生所需的烟气。以4种煤粉为再燃燃料，以1g/min的恒流量进行再燃试验，研究了再燃热输入15%~ 25%、再燃温度1100 ~ 1400 ℃、再燃飞灰含碳量、煤粉细度、再燃区化学计量比等再燃工艺参数。在再燃热输入为25%的条件下，兖州煤纯煤再燃NO还原率最高可达47%。最佳再燃温度为1300 ℃左右，燃料的富化学计量比是必不可少的;煤粉细度可以略微提高再燃能力。用于氨注入的温度窗口为约700摄氏度（约1100摄氏度）。CO在较低温度下能提高NH3能力。在高级再燃期间，测得72.9%的NO还原。选择性非催化NO（x）还原（SNCR）技术要实现70%以上的NO还原，NH3/NO化学计量比应大于5，而高级再燃技术仅使用常规SNCR技术中常用的氨气剂量。机理研究表明，CO的氧化促进了H_2O的分解，使自由基池丰富，从而在较低温度下引发整个反应。
Pulverized coal reburning, ammonia injection and advanced reburning in a pilot scale drop tube furnace were investigated. Premix of petroleum gas, air and NH3 were burned in a porous gas burner to generate the needed flue gas. Four kinds of pulverized coal were fed as reburning fuel at constant rate of 1g/min. The coal reburning process parameters including 15% approximately 25% reburn heat input, temperature range from 1100 degrees C to 1400 degrees C and also the carbon in fly ash, coal fineness, reburn zone stoichiometric ratio, etc. were investigated. On the condition of 25% reburn heat input, maximum of 47% NO reduction with Yanzhou coal was obtained by pure coal reburning. Optimal temperature for reburning is about 1300 degrees C and fuel-rich stoichiometric ratio is essential; coal fineness can slightly enhance the reburning ability. The temperature window for ammonia injection is about 700 degrees C approximately 1100 degrees C. CO can improve the NH3 ability at lower temperature. During advanced reburning, 72.9% NO reduction was measured. To achieve more than 70% NO reduction, Selective Non-catalytic NO(x) Reduction (SNCR) should need NH3/NO stoichiometric ratio larger than 5, while advanced reburning only uses common dose of ammonia as in conventional SNCR technology. Mechanism study shows the oxidization of CO can improve the decomposition of H2O, which will rich the radical pools igniting the whole reactions at lower temperatures.