煤气化颗粒中碱金属的扩散/反应动力学机理与模型研究

Xinjiang Zhundong coal field has huge amounts of proven reserves. However, the usage of the Zhundong coal in comubstion/gasification furnaces can lead to operational difficulties such as agglomeration, slagging, fouling or corrosion of downstream processes, seriously affecting the safely, stably operation of the equipment due to its high alkali content. In order to provide a better understanding of the physical and chemical phenomena behind the process, the application will focus on mechanism of precipitation and transformation of the alkali species during gasfication, internal diffusion/reaction kinetics of alkali species in the porous particle and investigation of related influence factors, through extensive experimental testing and modeling researches combined with the theoretical analysis. It is expected to reveal the process mechanism and kinetics behavior of precipitation and transformation of the alkali species, realize the qualitative/quantitative description of precipitation and transformations, expound the related factors influence and interaction between the gasification process and alkali species precipitation and transformation process, deepen the understanding of the nature of process. Finaly, an accurate and reliable scientific evidence and theoretical prediction model method for high alkali coal usage of gasification will be provided, and a guide for the optimation and control of industrial process of usage of the high alkali coal.

新疆准东煤田储量丰富，但高碱含量特性导致其在燃烧/气化等利用过程中易造成炉内聚团、尾部受热面结焦沾污和腐蚀等问题，严重影响设备的安全稳定运行。为掌握高碱煤在利用过程中特有的物理化学现象，本项申请拟采用实验和建模的方法，结合理论分析，逐级深入地对气化条件下单颗粒高碱煤中碱金属的析出转化过程机理、碱金属物质在多孔颗粒内部的扩散/反应动力学行为理论以及相关因素影响进行研究。通过对上述内容的研究，有望揭示碱金属析出转化的中间过程机理及动力学控制机理，实现煤气化碱金属析出转化过程的定性/定量描述，阐明气化进程与碱金属析出转化过程的因素影响及关联交互作用，加深对碱金属析出转化过程的本质认识和理解，并最终为高碱煤利用过程中碱金属的析出转化提供准确、可靠的科学依据和理论预测模型方法，并为实现工业中高碱煤利用过程的优化控制提供理论指导。

本项目结合实验测量和模拟预测的方法，对热解、气化条件下多孔煤颗粒中Na盐物质析出转化行为机理及Na盐物质对煤颗粒热解、气化特性的影响特性开展研究，为解决我国新疆准东煤在非掺混流化床气化过程的结焦、沾污等问题，以及过程优化控制提供理论指导。通过在小型电加热流化床反应器和TG-DTA-EI/PI-MS（Skimmer接口）电-光离子质谱同时在线测量系统上的实验测量，定性/定量获得了Na盐物质在热解、气化等不同阶段的析出转化行为过程机理，获得了不同预处理方法对准东煤热解、煤焦气化特性的影响作用规律；基于实验数据分析，建立了可用于描述多孔颗粒煤气化条件下碱金属析出转化的扩散/反应动力学数学模型，并对微米级单颗粒煤内碱金属Na元素物质析出转化行为进行了数值仿真研究。研究结果表明，Na盐物质的析出转化主要发生在焦炭气化阶段，且不同赋存形态的Na盐物质对热解产物组成、热解速率等特性具有重大影响，而Na盐物质以及热解条件对后续半焦的气化特性具有重大影响。参加2次国内会议，2次国际会议，国内国际会议论文3篇，发表SCI论文3篇。