添加CaO的准东煤中温水蒸气气化特性的研究

以内在碳捕集气化为背景,利用加压热重分析仪开展CaO对准东煤中温(700-750℃)水蒸气气化反应动力学特性的影响研究,采用氮气吸附仪对准东煤焦的比表面积进行测定,并对煤中不同赋存形态碱金属含量采用电感耦合等离子体发射光谱仪(ICP-OES)进行测定。结果表明,准东煤中的可溶性碱金属元素能有效催化气化反应,引入的二氧化碳吸收剂CaO与碱金属间表现出协同催化作用。水洗后的准东煤焦活性最高,添加CaO后的气化活性最好。Ca/C物质的量比对准东煤气化特性的影响研究表明,CaO的添加存在饱和量,Ca/C物质的量比为1.0较为合适。利用均相模型(HM)、缩核模型(SCM)以及修正体积模型(MVM)对反应动力学实验数据进行拟合,结果表明,修正体积模型可以较好地体现添加CaO的准东煤中温水蒸气气化反应动力学特性,由此获得反应活化能为160.90 kJ/mol。

Steam gasification characteristics of Zhundong coal with additive CaO at medium temperature

The steam gasification characteristics of Zhundong coal with additive CaO at medium temperature of 700-750℃ were investigated by Thermal Gravimetric Analyzer (TGA). The Brunauer-Emmett-Teller (BET) specific surface area of the coal char was tested by N₂ adsorption, and the different occurrence modes of alkali metals in the coal were analyzed by Inductively Coupled Plasma Optical Emission Spectrometer (ICP-OES). The results show that the soluble sodium could catalyze the gasification reaction effectively and the water-washed coal has the highest activity. The additive CaO and the inherent sodium have a synergistic effect during the gasification, and the optimal Ca/C molar ratio is 1.0. The kinetic parameters were calculated using the homogeneous model (HM), the shrinking core model (SCM) and the modified volumetric model (MVM), respectively. The results indicate that the MVM is better to represent the char steam gasification reaction, and its activation energy calculated by the MVM is 160.90 kJ/mol.