一种褐煤煤焦水蒸气和CO2气化活性的对比研究

面向循环流化床褐煤热解-部分气化-残炭燃烧分级转化工艺，以宁夏石沟驿褐煤为原料，采用水平管式炉在700～950 ℃，以快速热解和慢速热解方式制备煤焦，考察煤焦表面形貌和结构随制焦条件的变化。利用热分析技术研究气化温度、热解温度和热解速率对煤焦水蒸气和CO2气化反应活性的影响。结果表明：煤焦气化反应速率主要受气化温度影响，受热解温度的影响相对较小；煤焦分别与水蒸气和CO2气化的活性有较大差异，差异随着气化温度的升高而减小；与煤焦的水蒸气气化相比，热解条件对煤焦的CO2气化活性影响更大；煤焦水蒸气气化和CO2气化的反应性指数之间的关系可用二次曲线进行描述，在10%～80%碳转化率范围内分布活化能存在良好的线性关系。

A contrastive study on reactivity of brown coal char gasification with steam and CO2

Based on the staged conversion technique of brown coal pyrolysis，partial gasification and residual carbon combustion in circulating fluidized beds，rapid and slow coal char were produced from the brown coal of Shigouyi coal mine in Ningxia，at the temperatures from 700 ℃ to 950 ℃ in a horizontal tube furnace.The effects of pyrolysis conditions on the surface morphology and structure of the coal chars were investigated.A contrastive study was conducted using thermogravimetric technology，testing the reactivity of coal chars gasification with steam and CO2.The effects that gasification temperature，pyrolysis temperature and pyrolysis rate have on the gasification reactivity of coal chars were also analyzed.The results show that gasification temperature is the most important factor influencing gasification rate，while pyrolysis temperature has a weaker effect.However，there is great difference in gasification reactivity between steam and CO2，which decreases as gasification temperature rises.Compared to steam gasification，pyrolysis conditions have greater influence on CO2 gasification.The relation of reaction indexes between steam and CO2 gasification can be expressed using a quadratic regression equation，and a linear relationship exists between the distributed activation energy of both reactions in a carbon conversion range from 10% to 80%.