Liu Changqi, Liu Zhenyi, Liu Qingming, Liu Qiqi, Liu Chuang, Xiu Zihao, Yang Jun, He Zongling, Wang Zhisong
National Key Laboratory of Explosion Science and Safety Protection, Beijing Institute of Technology, Beijing 100081, China.
ACS Omega. 2024 Jun 17;9(26):28293-28310. doi: 10.1021/acsomega.4c01763. eCollection 2024 Jul 2.
The addition of ammonia and hydrogen into natural gas fuel is an effective method to reduce carbon emissions. This study aims to investigate the effect of adding ammonia and hydrogen on the mechanism of natural gas combustion and emission characteristics. Based on a self-developed mixed gas deflagrate experimental platform, the deflagrate characteristics, emission characteristics, and chemical reaction kinetics mechanism of mixed gas fuels under different composition ratios (natural gas 0-100%, hydrogen 10-85%, and ammonia 0-100%) were studied. The results indicate that the propagation of the deflagration shock wave can be categorized into an initial stage ( < 3 m) and a development stage ( > 3 m) based on the observed trend of shock wave intensity variation with distance. The intensity of the deflagration shock wave for the mixed gases increases monotonically as the hydrogen content ratio rises. In contrast, the impact of the ammonia content ratio on the shock wave intensity exhibits a distinct pattern that varies with changes in the equivalence ratio and hydrogen content ratio. In terms of carbon emissions per unit of heat value produced by the fuel, adding hydrogen to natural gas proves to be more effective at reducing carbon emissions than adding ammonia. When the ammonia content ratio is 50% and the hydrogen content ratio is 40%, the combustion performance of the mixed gas fuel is similar to that of natural gas, but its carbon emissions are lower than 30% of natural gas, making it a new type of mixed fuel with potential application value; the interaction between reflected pressure waves and flames is the main reason for the fluctuation of deflagrate shock wave pressure; ammonia lowers the temperature of the reaction system by reducing the concentration of OH radicals.
向天然气燃料中添加氨和氢气是减少碳排放的有效方法。本研究旨在探究添加氨和氢气对天然气燃烧机理及排放特性的影响。基于自主研发的混合气体爆燃实验平台，研究了不同组成比例（天然气0 - 100%、氢气10 - 85%、氨0 - 100%）下混合气体燃料的爆燃特性、排放特性及化学反应动力学机理。结果表明，根据观察到的冲击波强度随距离的变化趋势，爆燃冲击波的传播可分为初始阶段（< 3 m）和发展阶段（> 3 m）。混合气体的爆燃冲击波强度随氢气含量比的增加而单调增加。相比之下，氨含量比对冲击波强度的影响呈现出随当量比和氢气含量比变化而变化的明显规律。就燃料产生的单位热值碳排放量而言，向天然气中添加氢气在减少碳排放方面比添加氨更有效。当氨含量比为50%且氢气含量比为40%时，混合气体燃料的燃烧性能与天然气相似，但其碳排放量低于天然气的30%，使其成为一种具有潜在应用价值的新型混合燃料；反射压力波与火焰之间的相互作用是爆燃冲击波压力波动的主要原因；氨通过降低OH自由基浓度来降低反应体系的温度。
