基于微波非热效应作用的煤中硫迁移行为与脱除机理研究

The atmospheric pollution pattern with the coal-smokes of SO2 is determined by the characteristics of coal-based energy consumption of our country. Therefore, it is of great significance to carry out the research on new type theory and technology of coal desulfurization for promoting clean coal utilization and improving the ecological environment. Microwave works as a special energy tool, whose application in coal desulfurization has attracted the high attention of peer experts. In this subject, the chemical speciation of sulfur components in coal and intrinsic energy of sulfur chemical bond is to be analyzed initially. Then, the dielectric properties of coal and sulfur-containing impurities, and their influence on the response mechanism of the microwave electromagnetic field and energy effect mechanism will be investigated. By studying the approaches and methods of catalytic regulation by chemical additives, the speciation migration characteristics and distribution laws of sulfur in coal with microwave irradiation will be clarified accordingly. Through designing sulfur-containing model compounds, simplifying the reaction system of desulfurization and reducing affecting factors, the breaking and depolymerization of sulfur chemical bonds of various model compounds by the non-thermal effects of microwave will be explored with several modern analyzing methods. Combined with the analysis and reverse speculation of the components and configuration of desulfurization intermediates and final products, the mechanism of microwave desulfurization is firstly explored. Thereby, the mechanisms of speciation migration of sulfur-containing components and sulfides during the process of which are to be revealed. Subsequently, it is expected that through establishing the corresponding reaction dynamic model and finding the optimal technical condition of coal desulfurization by microwave, the theoretical basis will be provide for developing industrial-scale microwave desulfurization technology.

我国以煤为主的能源消费特点决定了SO2煤烟型大气污染格局，因此，开展新型煤炭脱硫理论与技术研究对提高我国煤炭洁净利用水平和改善生态环境具有重大意义。微波作为一种特殊能量手段，在煤脱硫领域的应用引起了同行专家的高度关注。本项目从煤中含硫组分赋存形态、硫化学键本征能量分析入手，探讨煤与含硫组分的介电特性及其对微波电磁场的响应特性和能量作用机制，研究化学助剂催化调控途径和方法，掌握微波辐照下煤中硫的形态变化特征及分布规律。通过含硫模型化合物的构建，简化脱硫反应体系和复杂研究对象影响因素，并利用多种现代分析测试手段，探索微波非热效应对各种模型化合物硫化学键的断裂和解聚作用。结合对脱硫中间体及产物组成结构的分析和逆推，探索微波脱硫机理，从而揭示煤微波脱硫过程中含硫组分和硫化物形态演变机制及硫迁移行为，建立相关反应动力学模型，并找出煤炭微波脱硫的最佳工艺条件，为开发工业规模的微波脱硫技术提供理论依据。

开展高硫煤微波脱硫理论与技术研究对提高我国煤炭洁净利用水平和改善生态环境具有重大意义。.本项目从煤中含硫组分赋存形态和类煤含硫模型化合物分子性质等方面入手，主要对山西高硫煤中含硫组分的赋存机制进行了分析，并筛选了11种类煤模型化合物。.探讨了煤与含硫组分的介电特性及其能量作用机制，建立了煤炭介电性质测试系统并优化了测试工艺参数。研究发现，通过氧化处理可增强煤中含硫基团对微波的吸收能力，微波场中有机含硫分子的加热速率比其他分子快且可实现选择性加热。结合介电性质分析和含硫键键解离能计算，构建了含硫键理论断裂时间预测模型。.量子化学计算结果表明：微波脱硫过程中，氧化助剂首先进攻含硫模型化合物分子中的硫原子。通过氧化处理可降低分子中含硫键的键解离能并提高分子的偶极距，从而提高含硫键的断裂几率。有关非热效应的研究结果表明，外加适宜的电场，可增强分子反应活性和硫原子亲电活性，降低反应的吉布斯自由能变和反应活化能，并提高反应速率。.煤炭微波脱硫过程中，煤中的硫铁矿硫最终转化为硫酸盐，而低价态有机硫倾向于被氧化为砜类，少部分硫醇硫醚类的含硫键在氧化过程中断裂生成含硫自由基，并进一步氧化为可溶性盐或磺酸类，而大部分有机硫最终以氧化态形式残留在煤大分子结构中。.通过工艺条件的优化研究，找到了微波联合氧化助剂脱硫的最佳工艺和条件，采用微波联合氧化助剂的脱硫方式，最高脱硫率可达到61.03%。.通过本课题的研究，初步掌握了煤与含硫组分对微波的响应特性，阐明了微波脱硫机制，弄清了硫的形态变化特征及迁移行为，掌握了化学助剂催化调控途径和方法，为煤炭微波脱硫的应用提供了理论依据。