蒙东褐煤结构热演变及水蒸气气化历程解析

Based on understanding the theory of chemical composition, valence bond type and structure of lignite coal , aim at the three topics of structure thermal evolution, pyrolysis and gasification process of coexistence and calcium bonding evolution in the process of steam catalytic gasification for high hydrogen synthesis gas , according to the high oxygen content/ high water content/ high ash content characteristic of MengDong lignite, regard （CxHyOz）n_MeaO_MebO as model basis of MengDong lignite，model compounds are adopted to simulate chemical model and the structural thermal evolution of MengDong lignite by using oxygen-poor oxidation performance testing in this project. Meanwhile, it is resolved that the relationship between thermodynamics and kinetics lignite steam gasification and the structural thermal evolution of MengDong lignite through decomposition and control of pyrolysis and steam gasification reaction process. Based on the above work，by modifying Ca/O/Si/Al content and ratio of MengDong lignite coal/coke and its corresponding model compounds， the effect of Ca/O/Si/Al content and ratio on the relationship between thermodynamics and kinetics lignite steam gasification and the structural thermal evolution of MengDong lignite were investigated and calcium bonding evolution in the process of steam catalytic gasification was illuminated. the catalytic effect of composite metal oxides on MengDong lignite structure thermal evolution and the steam gasification reaction was annotated via the composite metal oxide catalytic theory.

项目基于对褐煤化学组成、价键类型与结构理论认识的基础上，针对蒙东褐煤水蒸气催化气化制高氢合成气过程中结构热演变，热解与气化历程共存及Ca键合形态演化三个主题，根据蒙东褐煤的高氧，高水，高灰特性，以（CxHyOz）n_MeaO_MebO为蒙东褐煤的模型基础，采用缺氧氧化反应性能甄别蒙东褐煤结构热演变历程，并利用模型化合物模拟构建蒙东褐煤化学模型及其结构热演变过程。同时，通过对热解与水蒸气气化反应进程的分解与控制，进行蒙东褐煤水蒸气气化热力学和动力学及其与结构热演变相互关系的解析。在上述基础上，调变蒙东褐煤/焦及其相对应模型化合物的Ca/O/Si/Al含量及配比，考察Ca/O/Si/Al配比对蒙东褐煤结构热演变与水蒸气气化热力学与动力学进程及其相互关系的影响，阐明Ca在蒙东褐煤水蒸气催化气化过程中价键键合形态演变历程，并通过金属氧化物催化理论，诠释金属氧化物对蒙东褐煤结构热演变历程及水蒸气气化

项目从蒙东褐煤清洁利用出发，在对褐煤化学组成、价键类型与结构理论认识的基础上，采用程序升温，梯度等温，等温缺氧氧化反应三种反应模式以木质素/木质素焦、石墨/无烟煤、氧化石墨/氧化无烟煤等模型化合物的缺氧氧化反应性为标准，模拟解析了蒙东褐煤/焦的化学结构及其热演变历程，初步建立了褐煤的基本化学模型，并尝试揭示了褐煤的热解与气化热化学反应过程中结构热演变，明确了褐煤水蒸气气化反应存在的三种反应路径。项目通过对褐煤中低温催化热解过程与水蒸气催化气化制氢反应过程相互关系的辨识，发现了褐煤中低温热解的产物是水蒸气催化气化制氢的反应物，催化热解的钾、钙元素同时催化水蒸气气化制氢过程。其中，钾元素在褐煤中低温热解过程中促使氢气提前逸出，一氧化碳推后逸出，提高了煤焦中碳含量，降低了蒙东褐煤/焦水蒸气气化制氢反应温度200℃左右，氢气产量增加一倍。钙元素显著降低了褐煤中低温催化热解过程与水蒸气催化气化制氢反应过程的反应温度，并有效降低了褐煤中硫元素的逸出，提出了钙元素催化褐煤水蒸气气化反应的失活机理。项目对钾、钙元素来源进行了筛选，发现了环境废物电石渣与生物质向日葵秸秆是高效的钾钙元素来源，实现蒙东褐煤高效清洁利用的同时实现了环境废物的回收与生物质的利用，项目为褐煤高效清洁利用、环境废物回收和生物质资源利用提供了一定的理论与实践基础。