无烟煤高温火焰贫氧区喷氨降低NO<sub><i>x</i></sub>排放试验

许芸; 朱志祥; 董月红; 张乾; 徐静馨; 张忠孝; 李子祥; 乌晓江

doi:10.13205/j.hjgc.202501018

无烟煤高温火焰贫氧区喷氨降低NO_x排放试验

doi: 10.13205/j.hjgc.202501018

1. 国家能源集团科学技术研究院有限公司, 南京 210046;
2. 上海交通大学机械与动力工程学院, 上海 200240

基金项目:

低碳智能燃煤发电与超净排放全国重点实验室开放课题(D2021FK058)

详细信息

作者简介:
许芸(1981-),女,高级工程师,主要研究方向为大气污染治理新技术研究与工程管理。12059091@ceic.com

通讯作者:
乌晓江(1977-),男,研究员,主要研究方向为燃煤污染物控制技术。wxj9631@163.com

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出版历程
- 收稿日期: 2023-09-19
- 录用日期: 2024-03-12
- 修回日期: 2023-12-29
- 网络出版日期: 2025-03-21
- 刊出日期: 2025-03-21

Experimental study on nitric oxide reduction by urea solution injection into low-oxygen zone of anthracite coal combustion flame

1. Science and Technology Research Institute Co., Ltd., CHN Energy, Nanjing 210046, China;
2. School of Mechanical Engineering, Shanghai Jiao Tong University, Shanghai 200240, China

摘要

摘要: W火焰炉是燃用低挥发分煤种的主要炉型,其NO_x排放远高于常规煤粉锅炉,如何减排成为亟待解决的关键问题。在高温沉降炉试验平台上详细研究了无烟煤燃烧过程中过量空气系数、氨氮摩尔比(NH₃/NO_x)、温度等因素对高温富燃料区直喷尿素溶液降低NO_x排放的影响。结果表明:过量空气系数由1.05降低至0.75时,空气分级燃烧可以降低约30%的NO_x排放。在空气分级基础上向高温富燃料区通入尿素溶液可以进一步降低NO_x排放,较低的过量空气系数和较高的温度有利于提高尿素溶液的NO_x还原效率。1400 ℃或氧化性气氛下,最佳氨氮摩尔比为1.5;此时过量空气系数为0.75,高温富燃料区直喷尿素溶液可在空气分级基础上实现32.47%的NO_x还原效率,炉膛出口NO_x排放浓度最低可降至438.30 mg/Nm³。而在较低温度、还原性气氛下,最佳氨氮摩尔比为2.0。研究结果验证了燃无烟煤W火焰炉采用高温富燃料区直喷尿素溶液在降低NO_x排放方面的有效性。
- 无烟煤燃烧 /
- 过量空气系数 /
- 氨氮摩尔比 /
- 温度 /
- NO_x排放
Abstract: Down-fired boilers are designed to burn low-volatile coal, of which the NO_x emission is much higher than that of conventional coal-fired boilers. With the proposal of ultra-low emission standards for thermal power units, the efficient and low-cost reduction of NO_x emission in down-fired boilers has become a key issue to be solved urgently. Experiments were conducted in a high-temperature drop tube furnace to investigate the effects of excess air ratio (λ), NH₃/NO_x molar ratio (NSR), temperature, etc. on the NO_x reduction characteristics during anthracite coal combustion by urea solution injection into the high-temperature fuel-rich zone. The experimental results indicated that air-staging combustion could lower approximately 30% of NO_x emissions when the excess air ratio was decreased from 1.05 to 0.75. NO_x emissions could be further lowered by urea solution injection into a high-temperature reduction zone based on air-staging combustion, and a lower excess air ratio and higher temperature were conducive to the NO_x reduction efficiency of urea solution. The optimal NH₃/NO_x molar ratio was 1.5 under 1400 ℃ or oxidizing atmosphere. However, the optimal NH₃/NO_x molar ratio was shifted to 2.0 under relatively lower temperatures and a reducing atmosphere. Urea solution injection into a high-temperature fuel-rich zone could reduce 34.27% of NO_x emissions and achieve a minimum NO_x emission of 438.30 mg/Nm³ under the optimal experimental conditions, i.e., temperature of 1400 ℃, excess air ratio of 0.75, NH₃/NO_x molar ratio of 1.5. Our findings verify the effectiveness of urea solution injection into the high-temperature fuel-rich zone in lowering NO_x emission in down-fired boilers burning anthracite coal.
- anthracite coal combustion /
- excess air ratio /
- NH₃/NO_x molar ratio /
- temperature /
- NO_x emission

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