掌握炼焦煤中有机硫的禀赋特征, 认知微波对煤中有机硫结构的化学作用机制, 对丰富煤炭脱硫理论体系, 优化煤炭微波脱硫工艺, 开发煤精细加工新技术具有重要意义。 应用XPS和XANES表征炼焦煤中有机硫的主要赋存结构类型及其相对含量, 基于煤密度特性的差异, 探索有机硫类型及其含量的变化规律。 选择苯并噻吩和3-噻吩甲酸两种模型化合物, 分别进行915和2 450 MHz频率微波辐射实验, 通过Raman光谱研究模型化合物中含硫结构的变化特征, 利用Materials Studio进行量子化学模拟, 计算不同方向外加能量场作用下模型化合物的构型参数, 比较微波辐射前后, 模型化合物构象变化, 解析煤中含硫化学键对微波能量的响应机制。 XPS和XANES表征结果显示, 炼焦煤中硫以有机硫为主, 噻吩是煤中最主要的有机硫赋存形式。 随着炼焦煤密度级的增加, 噻吩硫相对含量逐渐减小, 硫醇(醚)和(亚)砜相对含量逐渐增大, 三类有机硫赋存含量趋于平均。 施加不同方向的外加能量场后, 苯并噻吩和3-噻吩甲酸中含硫化学键键长和键级变化不明显, 说明微波能量场对化学键的拉伸和扭转作用有限, 但是, 对模型化合物分子结构中的键角和偶极矩具有影响, 并且, 不同的能量场施加方向对键角和偶极矩的影响效果不一样。 Raman谱图分析显示, 915和2 450 MHz频率微波辐射后, 模型化合物中含硫化学键振动峰都出现了红移。 因此, 微波辐射影响了模型化合物微环境局部结构, 改变了其分子构型和分子极性, 减小了晶格的振动恢复力, 削弱了原子间的相互作用力, 促进了含硫化学键的断裂及硫的解离。 同时, 发现915 MHz频率微波辐射具有比2 450 MHz更加明显的作用效果。

To understand the endowment characteristics of the organic sulfur in coking coal and know about the chemical mechanism of microwave to organic sulfur in coal are of great importance to the enrichment of the coal desulfurization theory, optimization of the microwave desulfurization process of coal and development of new technology of fine coal processing. XPS and XANES were used to represent the main structure types of organic sulfur and the relative content of organic sulfur in coking coal. Based on the difference of coal density characteristics, we explored the types and content changes of organic sulfur. The benzothiophene and 3-thiophenecarboxylic acid were selected for microwave irradiation experiments at 915 and 2 450 MHz. The variation characteristics of sulfur structures in the model compounds were studied by Raman spectroscopy. The quantum chemistry simulation was performed using Materials Studio to calculate different directions. Materials Studio was used to simulate the configuration parameters of model compounds under energy fields in different directions. We compared the conformation changes of the model compounds after microwave radiating, and analyzed the response mechanism of the sulfur chemical bonds in the coal to the microwave. The XPS and XANES characterization results showed that sulfur in coking coal is dominated by organic sulfur, and thiophene is the most important form of organic sulfur. With the increase of the densities of coking, thiophenic content decreases relatively, a thiol (ether), and (sub) sulfone gradually increase, and the content of three types of organic sulfur tends to be average. After applying the applied energy fields in different directions, the chemical bonds length and bond level of sulfur in benzothiophene and 3-thiophenecarboxylic acid were not obvious, indicating that the microwave energy fields have limited stretching and torsion of chemical bonds. However, there had influence on the bonds angle and dipole moment in the molecular structures of the model compounds by different energy fields application directions. Raman spectrum showed that the vibration peaks of sulfur chemical bonds in the model compounds were red-shifted after microwave irradiation at 915 and 2 450 MHz. Therefore, microwave radiation affected the local structures of the model compounds microenvironment, and changed their molecular configuration and molecular polarity. At the same time, the vibration recovery force of the crystal lattice was reduced, the interaction force between atoms was weakened, and the fracture of sulfur chemical bonds and the dissociation of sulfur were promoted. It was found that the 915 MHz microwave radiation had more obvious effects than 2 450 MHz.