【作者】 高晶晶；

【导师】 冯丽娟；

【作者基本信息】 中国海洋大学 ， 分析化学， 2007， 硕士

【摘要】 随着人们环保意识的加强,柴油脱硫技术日益受到关注。目前降低柴油中硫含量的方法主要有加氢脱硫和非加氢脱硫。加氢脱硫技术要求高温、高压、氢环境以及贵金属催化剂等苛刻条件,设备投资和操作费用相对比较昂贵,且对于稠环噻吩类硫化物及其衍生物的脱除比较困难。吸附脱硫是新的有效脱除FCC柴油中硫化物的方法,具有操作简单、投资费用少、无污染、适合于深度脱硫等优点,它是一项具有广阔发展空间及应用前景的新技术。本文以活性炭为载体,CuO、ZnO和硝酸等为改性剂,采用等体积浸渍法制备了一系列吸附脱硫剂;采用静态吸附法和固定床动态吸附法对脱硫剂的吸附性能进行评价。考察了活性炭的种类和粒度、金属氧化物的负载量、焙烧温度、焙烧时间、脱硫温度、空速、油剂比等因素对脱硫剂吸附性能的影响,并对脱硫剂的硫容进行计算。筛选出了适宜的吸附脱硫和最佳吸附剂制备条件,并对脱硫剂进行再生研究和物化性质表征分析,为吸附脱硫技术的工业化提供一定的理论依据。研究结果表明,活性炭基吸附剂能够有效地脱除柴油中的含硫化合物。改性后活性炭的吸附脱硫性能要好于活性炭原样(AC);活性炭负载CuO(AC-A)的脱硫性能要好于负载ZnO(AC-B),活性炭混合负载CuO/ZnO(AC-C)的脱硫性能与单独负载CuO或ZnO相差不大;活性炭经硝酸活化后再负载CuO(AC-N-A)的脱硫性能大大提高,其脱硫性能要好于直接负载CuO。活性炭负载CuO和ZnO主要脱除了柴油中二苯并噻吩及其衍生物。表面酸碱性官能团测定结果表明,所制备的脱硫剂表面碱性官能团含量大于表面酸性官能团含量,其表面酸量大小:AC-N-A>AC-C>AC-A>AC-B>AC,表面碱量大小:AC-C>AC-B>AC-A>AC-N-A>AC。焙烧和硝酸活化对活性炭的比表面积、孔容和平均孔径的影响不大,其最可几孔径主要集中在20-30?之间。差热-热重分析表明,硝酸锌晶体与硝酸铜晶体受热到350℃基本完全分解为CuO和ZnO,活性炭在200-550℃之间受热稳定。X射线衍射分析表明,脱硫剂AC-A在350℃下焙烧出现了Cu2O的衍射峰,这是C将部分CuO还原为Cu2O;在500℃和700℃下焙烧出现了单质Cu的衍射峰,这是C将部分Cu的氧化物还原为单质Cu;吸附脱硫后AC-A中Cu2O的衍射峰消失,这可能是Cu2O参与了硫的脱除;脱硫剂AC-B中没有发现Zn以任何物相存在的衍射峰,这说明活性组分均匀分散在活性炭表面。脱硫剂用于FCC柴油吸附脱硫评价结果表明,脱硫剂AC-A、AC-B、AC-C和AC-N-A的吸附饱和硫容分别为0.587%、0.531%、0.596%和0.808%;脱硫剂用于模型化合物吸附脱硫评价结果表明,AC、AC-A、AC-B和AC-N-A对噻吩的吸附饱和硫容分别为0.261%、0.325%、0.298%和0.470%,对苯并噻吩的吸附饱和硫容分别为1.076%、1.354%、1.251%和1.826%,脱硫剂能够选择性吸附脱除苯并噻吩。所制备的脱硫剂吸附饱和硫容大小:AC-N-A>AC-C>AC-A> AC-B>AC。静态吸附脱硫评价结果表明,在CuO负载量为4.0%,ZnO负载量2.0%,油剂比1.0,浸泡时间2h,脱硫温度80℃,脱硫剂AC-A、AC-B、AC-C和AC-N-A的最大脱硫率分别为45.27%、44.40%、45.76%和60.95%。固定床动态吸附脱硫评价结果表明,在CuO负载量为4.0%,ZnO负载量2.0%,焙烧温度350℃,焙烧时间2.0h,脱硫温度80℃,空速2.0h-1,油剂比1.0时,脱硫剂AC-A、AC-B和AC-C的最大脱硫率分别为46.98%、43.91%和47.82%;在CuO负载量为4.0%,焙烧温度350℃,焙烧时间2.0h,脱硫温度100℃,空速2.0h-1,油剂比1.0时,脱硫剂AC-N-A的最大脱硫率为70.60%。脱硫剂AC-N-A再生研究结果表明,采用气体吹扫热再生和有机溶剂洗脱再生对失活后脱硫剂有一定的再生效果。更多还原

【Abstract】 The desulfurization of diesel fuel is of great significance while the regulation of sulfur content in liquid transportation fuel is becoming more and more stringent. At present, the main way to reduce sulfur content in diesel oil is hydrodesulfurization (HDS) and non-hydrodesulfurization. Hydrodesulfurization technology needs harsh conditions as follows: high temperature, high pressure, hydrogen environment, the noble metal catalysts and high operating costs. Furthermore, removal of thiophene sulfide and its derivatives are more difficult. However, adsorptive desulfurization is a new and effective method of removing sulfur from FCC diesel oil, which has some advantages as follows: simple operation, low investment, no pollution and suitable for deep desulfurization. Therefore, adsorptive desulfurization is a broad space for development and application.In this paper, activated carbon based adsorbent, loaded with copper oxide, zinc oxide and nitric acid was prepared by incipient wetness impregnation methods. Removal performance of sulfur from FCC diesel oil was evaluated using the two methods of static adsorption and dynamic adsorption in a fixed bed reactor. The effects of preparation parameters of adsorbents and operating conditions on sulfur removal performance of diesel oil were intensively discussed, such as the kind and granularity of activated carbon, loading amount of active component, calcination temperature and time, desulfurization temperature, space velocity and ratio of oil to adsorbent were studied, and the saturation sulfur capacity of desulfurizers was calculated. In the present study, the operation parameters on sulfur removal performances and optimal adsorbents were chosen, the disabled adsorbents were regenerated and physical and chemical properties of adsorbents were characterized. The practice experiences were provided for the industrialization of adsorptive desulfurization.The results indicated that, the sulfur compounds in diesel oil were effective to remove over activated carbon based adsorbent. Desulfurization performance was enhanced when active component was supported with active component, the sulfur removal efficiency decreased in the order of activated carbon loaded with CuO>ZnO, denoted as AC-A and AC-B respectively. When activated carbon was loaded with CuO/ZnO, denoted as AC-C, the sulfur removal efficiency is similar to AC-A and AC-B. When activated carbon was pretreated by nitric acid before loaded with CuO, denoted as AC-N-A, its sulfur removal efficiency was greatly enhanced comparing to AC-A. The GC-FPD chromatograms of FCC diesel oil showed that activated carbon loaded with CuO or ZnO preferred to adsorbe dibenzothiophene and its derivatives compared with other sulfur components.The content of surface basicity functional groups on desulfurizers was more than the contents of surface acidity functional groups, the content of surface basicity functional groups decreased in the order of AC-N-A>AC-C>AC-A>AC-B>AC, and the content of surface basicity functional groups decreased in the order of AC-C> AC-B>AC-A>AC-N-A>AC. Calcination and nitric acid activation did not change the surface area, pore volume and average pore diameter, and most probable pore diameters were in 20-30?. DTA-TG analysis showed that when the temperature reached 350°C, copper nitrate crystals and zinc nitrate crystals were decomposed into CuO and ZnO completely. Activated carbon was stable from 200°C to 550°C. X-ray diffraction analysis indicated that Cu2O diffraction peaks were found in desulfurizer AC-A under calcination temperature of 350°C, and Cu diffraction peaks were found under calcination temperature of 500°C and 700°C, because some copper oxide was deoxidize to copper. After desulfurization Cu2O diffraction peaks disappeared, it is probably because Cu2O participated in adsorption. Diffraction peaks in any form of Zn were not found in desulfurizer AC-B, because active component was dispersed on activated carbon.The results of removal performance of sulfur from FCC diesel oil and model diesel oil showed that, the saturation sulfur capacities over AC-A, AC-B, AC-C and AC-N-A was 0.587%, 0.531%, 0.596% and 0.808% respectively, the saturation sulfur capacities of thiophene over AC, AC-A, AC-B and AC-N-A was 0.261%, 0.325%, 0.298% and 0.470% respectively, the saturation sulfur capacities of benzothiophene over was 1.076%, 1.354%, 1.251% and 1.826% respectively. The desulfurizers prefer to selectively remove benzothiophene compared with thiophene. The saturation sulfur capacities of desulfurizers decreased in the order of AC-N-A> AC-C>AC-A>AC-B>AC.The static adsorption results indicated that when loading amount of CuO and ZnO, desulfurization temperature and time, ratio of diesel oil to adsorbent were 4.0%, 2.0%, 80°C, 2.0 h, 1.0, the sulfur removal efficiencies over AC-A, AC-B, AC-C and AC-N-A reached the maximum of 45.27%, 44.40%, 45.76% and 60.95% respectively. The dynamic adsorption results showed that, when loading amount of CuO and ZnO, calcination temperature and time, desulfurization temperature, space velocity, ratio of diesel oil to adsorbent were 4.0%, 2.0%, 350°C, 2h, 80°C, 2.0h-1, 1.0, the sulfur removal efficiencies over AC-A, AC-B and AC-C reached the maximum of 46.98%, 43.91% and 47.82% respectively. When loading amount of CuO, calcination temperature and time, desulfurization temperature, space velocity, ratio of diesel oil to adsorbent were 4.0%, 350°C, 2h, 100°C, 2.0h-1, 1.0 respectively, the sulfur removal efficiency over AC-N-A reached the maximum of 70.60%. Thermal regeneration at gas atmosphere and organic solvent washing regeneration were effective to the disabled desulfurizer AC-N-A.更多还原