Effect of H2O on the combustion characteristics of pulverized coal in O2/CO2 atmosphere
Effect of H2O on the combustion characteristics of pulverized coal in O2/CO2 atmosphere
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DOI：
10.1016/j.apenergy.2014.07.031
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发表时间：
2014-11
期刊：
影响因子：
11.2
通讯作者：
Yi Baojun;Liqi Zhang;F. Huang;Mao Zhihui;C. Zheng
中科院分区：
文献类型：
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作者：
Yi Baojun;Liqi Zhang;F. Huang;Mao Zhihui;C. Zheng
实际富氧燃烧气氛中的H2O浓度明显高于常规空气燃烧，这对煤粉的燃烧特性有很大影响。研究了水对煤粉在O2/CO2气氛中燃烧行为的影响。在O2/CO2/H2O气氛中，考察了3种中国煤在不同H2O和O2浓度下的着火温度、燃尽温度和综合反应活性。在高浓度富氧气氛下，研究了煤粉粒度和升温速率对煤粉燃烧的影响。结果表明，在O2/CO2气氛中，H2O的存在对煤和煤焦的燃烧特性有很大的影响，导致着火延迟大、燃尽快、综合反应活性高。对于褐煤来说，这些变化更加明显。在O2/CO2/H2O气氛下，H2O可以提高燃烧气氛的扩散率和热容，从而对煤粉燃烧有积极的作用。此外，通过对比O2/CO2气氛中添加H2O和不添加H2O时的燃烧反应性，得出含H2O气氛下煤的燃烧反应性机理与升温速率密切相关。
The H2O concentration in real oxy-fuel combustion atmospheres is significantly higher than that in conventional air combustion, which strongly affects the combustion characteristics of pulverized coal. This study studies the effect of H2O on pulverized coal combustion behaviour in O2/CO2atmosphere. The ignition temperature, burnout temperature and comprehensive reactivity of three types of Chinese coal at different H2O and O2concentrations in O2/CO2/H2O atmosphere were investigated. The effect of particle size and heating rate on the pulverized coal combustion was also studied under high-H2O-concentration oxy-fuel atmosphere. The results showed that the presence of H2O strongly affects the combustion characteristics of coal and coal char in O2/CO2atmosphere, leading to a greater ignition delay, faster burnout and higher comprehensive reactivity. These changes are more obvious for brown coal. Under O2/CO2/H2O atmosphere, H2O can improve the diffusivity and heat capacity of the combustion atmosphere and therefore has a positive effect on pulverized coal combustion. In addition, based on a comparison of the combustion reactivity between O2/CO2atmosphere with and without H2O, the mechanism of coal combustion reactivity in H2O-containing atmosphere is significantly related to the heating rate.