李玉凯,孙绍增,赵义军,等. 天然气调质煤粉再燃中关键参数的实验研究[J]. 煤炭学报,2024,49(7):1−8. doi: 10.13225/j.cnki.jccs.ZZ23.1507
引用本文: 李玉凯,孙绍增,赵义军,等. 天然气调质煤粉再燃中关键参数的实验研究[J]. 煤炭学报,2024,49(7):1−8. doi: 10.13225/j.cnki.jccs.ZZ23.1507
LI Yukai,SUN Shaozeng,ZHAO Yijun,et al. Experimental study of key parameters of natural gas-activated pulverised coal reburning[J]. Journal of China Coal Society,2024,49(7):1−8. doi: 10.13225/j.cnki.jccs.ZZ23.1507
Citation: LI Yukai,SUN Shaozeng,ZHAO Yijun,et al. Experimental study of key parameters of natural gas-activated pulverised coal reburning[J]. Journal of China Coal Society,2024,49(7):1−8. doi: 10.13225/j.cnki.jccs.ZZ23.1507

天然气调质煤粉再燃中关键参数的实验研究

Experimental study of key parameters of natural gas-activated pulverised coal reburning

  • 摘要: 针对煤粉再燃技术,提出了一种结合再循环烟气输送煤粉和天然气调质的方案。其目的在于提高再燃煤粉的还原能力,从而降低燃煤锅炉产生的氮氧化物排放。为了探索如何利用天然气中高活性成分,创造一个更有利于煤粉还原NOx的环境,利用模拟实际燃煤锅炉条件下的多反应控制段携带流反应器实验系统,研究了天然气调质的整个过程。结果表明,天然气调质产生的大量还原性物质,如CO*、OH*、H和CHi等优化了煤焦的物理化学结构,增强了煤焦还原氮氧化物的能力。与传统的再循环烟气输送煤粉相比,添加天然气调质后,NOx的还原效率显著提高了约12.23%。通过实验和数据分析,解析了天然气调质技术对于煤粉再燃的显著影响,并提出了在工程应用中的具体参数要求。从工程应用角度来看,为了实现高效率的氮氧化物还原,并兼顾煤粉的燃烬和经济性,需要对再燃区的过量空气系数、停留时间和燃料比进行精确控制,分别为0.8、0.6 s和20%。总的来说,采用天然气调质技术可在保证氮氧化物超低排放的同时,尽量减少活性气体的使用,从而提高系统运行的经济性。该灵活的天然气使用技术不仅在实验室条件下取得了良好的效果,也为工程实践提供了可行的方案,保证系统运行的经济性。

     

    Abstract: In the study of coal powder reburning technology, combining the coal powder delivery via recirculating flue gas and natural gas conditioning was proposed. The purpose of this approach is to enhance the reduction capability of coal powder reburning, thereby reducing the emission of nitrogen oxides from coal-fired boilers. The main objective of the research is to explore how to utilize the highly reactive components in natural gas to create a more favorable environment for coal powder to reduce nitrogen oxides. To achieve this, a detailed investigation of the entire process of natural gas conditioning was conducted using a multi-reaction control section with a flow reactor experimental system simulating actual coal-fired boiler conditions. The results revealed that the abundant reduction substances generated during natural gas conditioning, such as CO*, OH*, H, and CHi, optimized the physical and chemical structure of coal char, thereby enhancing its ability to reduce nitrogen oxides. Compared with traditional coal powder delivery via recirculating flue gas, the addition of natural gas conditioning significantly increased the efficiency of nitrogen oxide reduction by approximately 12.23%. Through experimental investigation and data analysis, the significant impact of natural gas conditioning technology on coal powder reburning was elucidated, and the specific parameter requirements for engineering applications were proposed. From an engineering perspective, the precise control of the excess air ratio, residence time, and fuel ratio in the reburning zone is essential to achieve a high-efficiency nitrogen oxide reduction while ensuring a complete coal powder combustion and economic feasibility. Overall, adopting natural gas conditioning technology can not only guarantee ultra-low nitrogen oxide emissions but also minimize the use of reactive gases, thereby enhancing the economic efficiency of system operation. This flexible use of natural gas technology has demonstrated some promising results in laboratory conditions and offers feasible solutions for engineering practice, ensuring the economic efficiency of system operation.

     

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