废旧轮胎催化热解过程中有机硫化物与催化剂和特征主体组份交互作用机制

Due to the existence of organic sulfur compounds in pyrolytic oil from used tire, the technology of tire pyrolysis for oil suffer from restrictions in terms of commercialization and industrialization. The catalytic pyrolysis process can enhance the production of valuable single ring aromatic compounds and decrease the sulfur amount in oil. But at the current stage, the knowledge of sulfur behavior during catalytic pyrolysis of used tire is still limited, thus cannot provide strong theoretical foundation for the preparation of effective catalyst. Based on previous researches and complex compositions of oil, the organic sulfur compounds were obtained according to the oil analysis. The metals were also loaded into zeolites to improve its catalytic ability. Through this project, the interaction between organic sulfur compounds and catalyst will be illustrated, including the effect of active sites of catalyst on adsorption and cracking of organic sulfur compounds and the sulfur and coke on catalytic ability of catalyst. The effect of major characteristic compounds in oil on organic sulfur compounds will also be studied. The combined effect of dehydrogenation and hydrogen cracking provided by different active sites of catalyst will also be interpreted. The implementation of this project shows theoretical significance and theoretical foundation for the production of valuable oils.

废旧轮胎热解油由于有机硫化物的存在，在工业应用中受到极大限制，阻碍其大模型商业化应用。废旧轮胎催化裂解具有既能够增加单环芳香族化合物的产量，又能降低焦油中硫含量的潜力。但现阶段对废旧轮胎催化热解过程中硫的催化转化机制缺乏足够的认识，不能为高效催化剂的制备提供理论依据。本项目根据前期研究基础，并考虑到焦油化学成分复杂，通过对热解油进行解耦调制并对催化剂进行改性，探索研究催化过程中有机硫化物与催化剂相互作用机制，确定催化剂不同活性位点对有机硫化物协同吸附及裂解机制，并掌握硫对积炭形成影响机制；对热解油主体成分进行归类，研究热解油中特征主体组份对有机硫化物催化转化影响机制，并阐明催化剂的脱氢和加氢裂解双重作用机制。通过本项目的实施，预期能够为废旧轮胎催化裂解制备低硫高品质热解油提供科学参考和理论依据，对废旧轮胎资源化利用具有重要意义。

废轮胎循环利用被国家列为循环经济重点发展领域。目前获得低含硫而富集芳香族化合物的高品质热解油是废轮胎热解技术的攻关难题，有机硫化物的催化反应路径及催化剂的作用机制缺乏了解。.本项目以典型橡胶及其硫化物为原料，通过实验和分子动力学模拟，研究了硫化橡胶热解特性及硫的迁移转化机制。硫化橡胶中的硫主要在低温下释放，而高温下热解油中的含硫组分会部分分解成热解气。液相产物中，硫在低温条件下主要以硫醇、硫醚和自由基碎片的形式存在，高温下主要以噻吩硫的形式存在。硫化橡胶热解气态含硫气体H2S会参与热解焦油的二次交互反应，同时促进热解过程中的环化反应与脱氢反应，但会抑制脱甲基反应。.开展改性分子筛原位吸附脱硫探究，并研究吸附前后催化剂的催化反应性，为开发高效抗硫催化剂提供指引。研究发现，分子筛催化剂会对H2S进行不同程度的化学吸附形成稳定的含硫物质，吸附程度遵循顺序：Zn/ZSM-5>ZnO/ZSM-5>HZSM-5的顺序；Zn金属改性分子筛主要通过形成ZnS实现原位吸附脱硫。经H2S吸附的金属改性催化剂，其裂解、芳构化能力均大幅降低。研究为废轮胎催化热解中硫的迁移及脱除提供指导。.在立式两段热解炉上开展硫化橡胶热解催化提质研究，阐明金属改性分子筛对硫原位脱除机理。金属的负载会降低分子筛上B酸的强度，并产生L酸。金属改性的ZSM-5催化剂会进一步促进挥发分裂解生成热解气，而金属改性的MCM-41催化剂对热解油产率的影响较小。金属改性催化剂通过与硫反应形成稳定的金属硫化物，使硫化橡胶热解油中的硫得到有效脱除。相较于Cu改性催化剂，Zn改性催化剂具有更强的脱硫作用。.通过本项目的开展，为废轮胎的原位催化提质协同脱硫提供了理论依据。