氨（NH3）具有零碳燃料属性，绿氨掺烧是煤电低碳化改造重要途径之一。在大规模应用NH3燃料之前，如何高效清洁的进行氨煤混燃已然成为国际热点问题。目前国内氨煤混燃的研究还集中在单个燃烧器以及中小型实验平台上，对实际大型燃煤锅炉电站组织氨煤混燃缺乏指导意义。为了研究在大型燃煤锅炉中组织氨煤混燃对燃烧以及污染物排放的影响，借助Ansys Fluent软件作为数值模拟平台，采用数值计算方法，开展了国内某1000 MW前后墙对冲燃煤锅炉掺氨燃烧特性研究，首先，在基于输入炉膛总热量不变的前提下，考察了在氨煤混燃比为30%时，氨气从不同位置喷入（中心风、一次风、内二次风和外二次风），以及在氨-煤燃烧不同比例（5%至50%）下对煤粉炉掺氨燃烧特性及NOx排放特性的影响规律。结果表明:氨气从中心风喷入的掺烧方式相较于从一次风、内二次风和外二次风喷入的方式会提升氨着火稳定性，同时炉膛出口NOx较其它位置排放最低仅有2311 mg/m3，且氨气从中心风管喷入炉膛对锅炉原始燃烧系统影响最小；随着在中心风氨气掺混比例的增加，炉膛出口处NOx呈现先上升后下降的趋势；同煤燃烧相比，氨燃料引入的燃料氮产生的NOx对NOx排放值起决定性作用，煤掺氨燃烧方式下抑制NOx的生成关键在于控制氨向NOx的转化。最后，提出了通过缩小氨喷口以提高氨喷入速度的整体燃烧器调整策略，模拟结果表明提高氨气喷入速度可有效控制氨向NOx的转化，NOx排放最高浓度从2538 mg/m3降低至1195 mg/m3，下降幅度达52.92%，NOx排放最低浓度从683 mg/m3降低至410 mg/m3，下降幅度达42.79%。本文的研究为燃煤锅炉掺氨燃烧改造提供理论指导。

Ammonia (NH3) possesses the attribute of a zero-carbon fuel, and green ammonia co-firing represents a key pathway for the low-carbon transformation of coal-fired power generation. Prior to the large-scale adoption of ammonia fuel, achieving efficient and clean ammonia-coal co-combustion has emerged as an internationally significant research focus. Currently, research on ammonia-coal co-firing in China remains largely concentrated on single burners and small-to-medium experimental platforms. This limits its applicability for guiding the implementation of ammonia-coal co-firing in actual large-scale coal-fired utility boilers. To investigate the influence of co-firing configuration on combustion characteristics and pollutant emissions in large-scale coal-fired boilers, this study employed the Ansys Fluent software as a numerical simulation platform. Numerical methods were used to analyze the combustion characteristics of ammonia-coal blends in a 1000 MW opposed-firing pulverized coal boiler in China. Firstly, while maintaining constant total furnace heat input, the effects of different ammonia injection positions (central air, primary air, inner secondary air, and outer secondary air) at a fixed 30% ammonia co-firing ratio (by heat input) were examined. Subsequently, the impacts of varying ammonia co-firing ratios (5% to 50%) were investigated. The results indicate that injecting ammonia through the central air duct improves ammonia ignition stability compared to injection via primary air, inner secondary air, or outer secondary air. Furthermore, central air injection yielded the lowest NOx emissions at the furnace outlet among the positions tested, measuring only 2311 mg/m3. This method also demonstrated the least impact on the boiler"s original combustion system. As the central air ammonia blending ratio increased, furnace outlet NOx exhibited an initial rise followed by a subsequent decrease. Compared to pure coal combustion, the fuel nitrogen introduced by ammonia plays a controlling role in the conversion of ammonia to NOx. Finally, an optimized burner strategy was proposed: reducing the ammonia injection port size to increase injection velocity. Simulation results confirmed that higher ammonia injection velocity effectively suppresses the conversion of ammonia to NOx. The maximum NOx emission concentration decreased from 2538 mg/m3 to 1195 mg/m3 (a 52.92% reduction), while the minimum concentration decreased from 683 mg/m3 to 410 mg/m3 (a 42.79% reduction). This research provides theoretical guidance for the retrofit of coal-fired boilers for ammonia co-firing.

国家能源投资集团有限责任公司科技项目（GJNY-24-112）