【作者】 司西强；

【导师】 夏道宏；

【作者基本信息】 中国石油大学 ， 化学工程与技术， 2010， 博士

【摘要】 国内外汽油加氢精制装置逐渐显露出的问题之一是加氢后汽油中重硫醇（大分子硫醇）含量上升,并且不能有效将其脱除。随着国内外对汽油硫含量标准越来越严格,研究加氢精制过程中二次硫化物的生成规律非常重要。本文针对汽油加氢精制过程中重硫醇及其它硫化物的生成问题开展系统的基础研究,具有重要的理论和实际意义。研究了在非临氢条件下无催化剂时1-己烯与硫化氢的热反应、γ-Al₂O₃上1-己烯与硫化氢的反应、加氢精制催化剂NiMoS/γ-Al₂O₃上1-己烯与硫化氢的反应,得出了不同条件下1-己烯与硫化氢的反应规律。结果表明在上述三种情况下,随着反应温度升高和硫化氢浓度增大,硫化物的生成量明显增加;对于1-己烯与硫化氢的热反应,随着1-己烯体积分数的增加,硫醇硫的量先增加后减少,总硫量呈增加趋势;在γ-Al₂O₃及NiMoS/γ-Al₂O₃催化剂上,硫醇硫及总硫的量都随着烯烃体积分数的增加呈增大趋势。1-己烯与硫化氢的热反应产物主要有己硫醇、己硫醚和二己基二硫化物;γ-氧化铝催化下反应的产物主要有己硫醇和己硫醚;加氢精制催化剂NiMoS/γ-Al₂O₃催化下反应产物主要有烷基噻吩和少量硫醇。根据产物GC-MS分析及反应的热力学分析,得到1-己烯与硫化氢的热反应主要是自由基机理,γ-氧化铝及NiMoS/γ-Al₂O₃催化下1-己烯与硫化氢反应遵循碳正离子反应历程。对临氢条件下NiMoS/γ-Al₂O₃催化剂上1-己烯与硫化氢的反应进行了详细研究。随着反应温度升高、氢初压增大、反应时间延长、催化剂用量增加,硫醇硫及总硫均呈先增加后减少的变化趋势;硫化氢的存在促进硫醇及总硫的生成;随着1-己烯体积分数的增加,硫醇硫的量先增加后减少,总硫的量呈增加趋势。通过考察HF改性催化剂和H3PO4改性催化剂对临氢条件下1-己烯与硫化氢反应的影响,发现随着酸浓度增加,改性催化剂上酸性位强度增大,催化生成的硫化物的量越多。综合NiMoS/γ-Al₂O₃催化剂上1-己烯与硫化氢反应规律、产物GC-MS分析及热力学分析,证明了临氢条件下NiMoS/γ-Al₂O₃催化剂上1-己烯与硫化氢的反应为碳正离子机理,并拟定了反应历程。临氢条件下对NiMoS/γ-Al₂O₃催化剂上其他烯烃包括环己烯、1,3-戊二烯及1-辛烯与硫化氢的反应进行了探讨,得到了和1-己烯与硫化氢反应相似的反应机理。为更贴近工业生产实际,以噻吩和1-己烯作为模型化合物,通过噻吩加氢脱硫原位生成硫化氢,考察了在临氢条件下NiMoS/γ-Al₂O₃催化剂上噻吩-烯烃体系生成重硫醇及其它硫化物的反应规律。随着反应温度的升高,体系中硫化氢含量越来越高,硫醇硫含量先增加后减少,总硫也逐渐减少;随着氢初压升高,反应体系中硫醇硫的量呈先增后减的趋势,噻吩硫含量逐渐减少,总硫含量是先减小后趋于平缓,逐渐表现出加氢脱硫反应强于烯烃与硫化氢的加成反应;随着反应时间的延长,反应体系中噻吩的加氢脱硫程度越来越高,剩余的噻吩硫越来越少,生成的硫化氢越来越多,生成的硫醇硫先增大后减小,总硫的量呈一直减少的趋势;随着催化剂量的增大,反应的加氢脱硫程度越来越大,剩余的噻吩硫、生成的总硫、硫醇硫均减少,生成的硫化氢的量增多。通过GC-MS分析,发现产物主要有四氢噻吩、2-己硫醇、1-己硫醇、烷基噻吩、烷基四氢噻吩、己硫醚、二硫化物等,这一结果为汽油加氢精制过程中重硫醇及其它硫化物的生成提供了证据。更多还原

【Abstract】 One of the problems for gasoline hydrotreating in our country was appeared gradually, which was in the process of gasoline hydrofining, the content of weight mercaptans was increasing after hydrodesulfurization process, and the weight mercaptans were not removed effectively. Other weight sulfides were formed which accompanied with the formation of weight mercaptans. In the process of gasoline hydrotreating, recombination mercaptans and other sulfides（for example thioether） were formed by the reaction of H2S and olefin, H2S was produced by the sulfides hydrodesulfurization and olefin was mainly from the feedstock of gasoline. With more and more severe standard for the sulfur in gasoline, the formation of weight mercaptan and other sulfides will be a big obstacle for producing clean gasoline. In this work, basic research on the formation of weight mercaptans and other sulfides was conducted systemically, which has important theoretical and practical meaning.The reaction of 1-hexene and H2S was studied, which were included no catalyst without hydrogen,γ-Al₂O₃ as catalyst without hydrogen, NiMoS/γ-Al₂O₃ as catalyst without hydrogen and NiMoS/γ-Al₂O₃ catalyst with hydrogen. The formation laws under different reaction conditions were obtained, and the reaction mechanisms were obtained though the analysis of thermodynamic data and GS-MS analysis. When the reaction condition was no catalyst and without hydrogen, the reaction mechanism obey free radical reaction pathway, product was mainly included hexanethiol, dihexyl sulfide and dihexyl disulfide. Whenγ-Al₂O₃ as catalyst without hydrogen, the mechanism was carbonium ion mechanism, sulfide compounds in product were mainly hexanethiol and dihexyl sulfide. When the condition was NiMoS/γ-Al₂O₃ without hydrogen, the mechanism was also carbonium ion mechanism, hexanethiol and thiophene derivatives were major sulfide compounds in product. When NiMoS/γ-Al₂O₃ as catalyst with hydrogen, the mechanism was also carbonium ion mechanism, sulfide compounds in product were mainly hexanethiol and dihexyl sulfide.Effects of NiMoS/γ-Al₂O₃ modified by HF or H3PO4 on the reaction of 1-hexene and hydrogen sulfide were detected. With the concentration of acid in the dipping solvent increasing, the content of mercaptan and other sulfide compounds was increasing, which proved that the reaction mechanism of 1-hexene and hydrogen sulfide over NiMoS/γ-Al₂O₃ with hydrogen was obey carbonium ion reaction pathway.The reaction of cyclohexene, 1,3-dipentene, 1-octene with hydrogen sulfide over NiMoS/γ-Al₂O₃ under hydrogen were detected, through the thermodynamic data and sulfur compounds in product, the mechanisms of reaction of cyclohexene, 1,3-dipentene, 1-octene with hydrogen sulfide were proposed.Take thiophene and 1-hexene as model compounds, the formation law and mechanism for the reaction of 1-hexene and hydrogen sulfide was detected for the thiophene-olefin reaction system over NiMoS/γ-Al₂O₃ under hydrogen. In this process, hydrogen sulfide was produced in situ by thiophene hydrodesulfurization. This work was closed to industry practicality, provided evidence for the formation of weight mercaptan and other sulfides, provided evidence for the formation of weight mercaptan and other sulfides, provided theoretical advices for controlling the formation of weight mercaptans. From the GC-MS analysis, the sulfur compounds in product were mainly tetrahydrothiophene, 2-hexanethiol, 1-hexanethiol, alkylthiophene, alkyltetrahydrothiophene, dihexyl sulfide and bisulfide, through the analysis of product and thermodynamic data, the mechanism was obtained and which was also obey carbonium ion pathway.更多还原