气流床煤气化过程中煤焦结构演变过程研究和离散网络模型模拟

Entrained-flow coal gasification technologies have been applied widely in modern coal chemical industry and have made significant economic and social benefits, for its higher capacity, higher efficiency and less harmful to environment compare with other coal gasification processes. However, with the expansion and deepening of the application, Fundamental research on entrained-flow coal gasification process is highly proposed to meet requirements to further improve the carbon conversion and optimize coarse slag and fine ash handling processes. Coal char solid structure change during the process has a major impact on the gasification process performance as well as slag and fine ash characteristics. The present project will firstly conduct rapid pyrolysis experiments under conditions similar to entrained-flow gasification processes, structural characteristics parameters of coal char will be obtained as the initial stage of gasification. A discrete structure model will be made to simulate structure characters of coal char from experiments. And the change of coal char during gasification will be simulated by the discrete structure model to reveal the relationship between changes of coal char structure and reaction rates of gasification as well as coal char fragment. Comparison will be made between simulation result and experimental data to validate the model proposed in the project. And the mode will also be used to forecast characters of coarse slag and fine ash in industrial entrained-flow coal gasification. This project will help to deepen the understanding of the basis of the entrained flow coal reaction to improve the design and operation of gasification reactor, and provide a theoretical basis for the development and optimization of coarse slag and fine ash treatment process in entrained-flow coal gasification applications.

气流床煤气化技术以其大型化的处理能力和高效环保的过程特征已经在现代煤化工中获得了大规模应用，并取得了显著的经济和社会效益。但是随着应用的扩大和深入，对其基础研究提出了更高的要求。煤焦固体结构在气化过程中的演变对气化过程工艺性能以及灰渣特征等都有重要影响。本项目针对气流床气化工艺特征，建立高温快速热解条件，获得煤焦初始阶段结构特征参数，建立煤焦结构离散模型，模拟气化过程中煤焦结构的演变，揭示煤焦结构演变与气化反应速率、煤焦破碎等之间的关系，并通过实验数据比对和验证模型演算结果，预测生成粗渣和细灰的结构基础特征。本项目有助于加深对气流床煤反应过程的基础认识，为气化反应器设计和粗渣和细灰的处理工艺的开发和优化提供理论基础。

气流床煤气化技术以其大型化的处理能力和高效环保的过程特征已经在现代煤化工中获得了大规模应用，并取得了显著的经济和社会效益。但是随着应用的扩大和深入，对其基础研究提出了更高的要求。煤焦固体结构在气化过程中的演变对气化工艺性能以及灰渣特征等都有重要影响。本项目针对气流床气化工艺特征建立了高温快速热解条件,探究了煤等含碳物质快速热解过程中颗粒破碎行为的机理，采用了Ohm原理和粘度流模型分析了脱挥发分过程，通过关联压差和破碎速率建立了破碎模型；基于渗流理论建立了单颗粒煤焦气化过程的离散模型，考察了煤焦初始结构和反应条件对气化过程煤焦结构演变特性的影响；采用高频炉开展了快速热解煤焦多次气化实验，并探讨了气化过程煤焦结构(碳微晶结构、孔隙结构和粒径分布)演变特性；利用高温热台显微镜可视化技术原位研究了高温气化过程不同煤阶煤焦固体结构演变对反应特性的影响，探讨了气化过程煤灰和含碳基质的交互作用以及焦-灰/渣转变机理。本项目不仅有助于加深对气流床煤反应过程的理论认识，而且为气化反应器的设计和粗渣/细灰处理工艺的开发和优化提供了基础数据。