3种煤焦的CO2气化反应特性及动力学模型

为探索不同煤种的气化反应特性及其动力学，以神木煤、新疆准东煤和印尼加里曼丹岛煤3种煤质差异较大的低阶煤为原料，在水平管式炉上制备了3种煤样的900 ℃快速热解煤焦，并采用热重分析仪考察了3种煤焦的非等温和等温气化特性，用分布活化能模型和随机孔模型拟合了煤焦的CO2气化反应速率与碳转化率间的关系。研究结果表明：煤焦的非等温气化反应活性和等温气化反应活性存在一定的差异，气化温度、煤种及煤灰分中的碱金属均影响气化反应活性，煤焦的等温气化反应活性为印尼加里曼丹岛煤焦的最高，神木煤焦最低，气化温度对神木煤焦的影响更显著。分布活化能模型和随机孔模型计算的活化能存在一定的关联；随机孔模型能较好地拟合煤焦气化实验数据。

CO2 gasification characteristics and dynamic models of three coal chars

In order to study on CO2 gasification characteristics and dynamic of different coal chars，based on circulating fluidized bed (CFB) coal gasification technology，three rapid pyrolysis coal chars were prepared with Shenmu coal， Xinjing Zhundong coal and Kalimantan coal，at 900 ℃ in an electric horizontal tube furnace.The CO2 gasification of the coal chars were analyzed by non-isothermal and isothermal thermogravimetric measurements.In order to investigate the suitable dynamic model for CFB gasification technology，the nth-order distributed activation energy model (DAME) and random pore model (RPM) were applied to analyze the relationship between the CO2 gasification reaction rate and the carbon conversion rates of the coal chars.The results showe that the gasification reactivities of the coal chars are different for non-isothermal and isothermal gasification;the gasification reactivity is affected by coal types，gasification temperatures and alkali metals in coal ash;the reactivity of Kalimantan coal char is the highest while Shenmu coal char is the lowest，and the influence of temperature on gasification is obvious for Shenmu coal char;the experimental data of coal chars are fitted well by RPM for CFB gasification and there is a relationship between DAME and RPM.