【作者】 张伟；

【导师】 李忠； Chunshan Song；

【作者基本信息】 华南理工大学 ， 化学工程， 2014， 博士

【摘要】 由于日益严格的环保法规，燃油深度脱硫已经成为亟待解决的环境问题。传统的加氢脱硫工艺不仅在高温高压条件下操作，而且消耗大量的氢气，研究和发展更加高效节能的燃油脱硫技术是全球炼油工业面临的巨大挑战。本文主要选择分子氧氧化法深度脱除燃油中有机硫为研究主题，拟研制出以分子氧为氧化剂，能在温和条件下高效脱除燃油有机硫的氧化脱硫技术，论文主要涉及非均相催化剂的制备，表征以及脱硫性能评价，研究催化剂催化脱硫性能构效关系，考察各工艺条件对有机硫转化率的影响。本文属化学反应与分离科学的研究领域，具有重要的科学研究价值和实际意义。本文提出乙腈萃取-臭氧氧化脱硫新工艺。研究结果表明：臭氧氧化苯并噻吩呈零级反应动力学，臭氧从气相传质到液相是反应控制步骤。乙腈作为萃取剂和反应溶剂，不仅可以选择性的萃取柴油中有机硫，而且可以促进柴油中二苯并噻吩类硫化物氧化反应速率；本文提出的新工艺在常温常压下，将商品柴油硫含量由1450μg/g脱除到50μg/g，脱硫率高达97%，油品回收率达99%。本文研究碳纳米管催化氧化脱硫。研究结果表明：碳纳米管可有效催化氧气氧化有机硫生成其相应的砜，其催化性能高于文献所报道的Co3O4/γ-Al2O3等催化剂近200倍。；Raman表征结果显示碳纳米管的石墨化程度越高，其催化氧化脱硫性能越高。反应后，碳纳米管由于石墨化程度下降导致其催化活性下降，通过在900℃热处理，碳纳米管的催化活性基本得到恢复，碳纳米管经五次循环再生，其催化活性仅下降4%。本文研究使用CuO-ZrO2-TiO2催化剂催化航空煤油原位生成有机过氧化物，进而氧化脱除油品中的有机硫。研究结果表明：相比于CuO，在负载型CuO催化剂存在下，油品中生成的过氧化物浓度更高，有机硫转化率越高。然而，在负载型CuO催化剂存在下，油品中过氧化物生成会存在明显的诱导期，且催化剂的孔径越小，过氧化物生成诱导时间越长；生成的过氧化物浓度越高，有机硫转化率越高。利用此工艺，油品硫含量可由初始的485μg/g降低到25μg/g，脱硫率高达95%。本文提出光辐射＆催化氧化两步法脱硫工艺，研究了影响过氧化物生成因素和催化剂催化氧化有机硫氧化的活性。结果表明，紫外光可大大促进有机过氧化物生成速率；在氧化有机硫过程中，过氧化物的自分解与过氧化物氧化有机硫是一对平行发生的竞争反应，这两个平行发生的竞争反应的热力学和动力学共同决定了有机硫转化的最佳反应温度。催化剂的孔径越大，越有利于有机硫在催化剂表面扩散，从而提高有机硫的转化率和过氧化物的利用率。本文提出一种新的光催化氧化-吸附耦合脱硫工艺。结果表明，有机硫在Ti(1-x)SixO2催化剂表面被光催化氧化生成其相应的亚砜，与此同时，产生的亚砜被选择性地吸附在催化剂表面而脱除；在不同组成的的Ti(1-x)SixO2催化剂中，Ti0.3Si0.7O2催化剂具有最高的脱硫性能；利用该工艺，在常温常压下，商用柴油的硫含量由220μg/g降低到31μg/g。更多还原

【Abstract】 Deep desulfurization of fuels has become very urgent task for petroleum refiningindustry due to strict environmental regulations to limit sulfur contents. Traditionaldesulfurization technology in refinery is hydrotreating, which operates at high temperatureand pressure, and consumes large amount of hydrogen. The petroleum refinery industy isfacing a major operational and economical challenge to develop highly efficientdesulfurization technologies.This work is mainly concerned with oxidative desulfurization (ODS) of liquid fuelsusing molecular oxygen, and it aims to develop selective oxidative desulfurization approachesto efficiently remove organosulfur compounds from fuels using molecular oxygen as theoxidant under mild conditions. Heterogeneous catalysts were synthesized, characterized, andevaluated for ODS. The influencing factors on ODS were investigated, and the catalyticactivities of catalysts for ODS were studied. This work belongs to the fields of chemicalreaction and separation science and is of important scientific interest and practicalapplications.A new acetonitrile extraction-ozone oxidation approach for ODS was proposed. Resultsshowed that the ODS reaction by ozone was zero-order reaction, and the O3diffusion stepfrom gas-phase to liquid-phase was the rate-determining step. Acetonitrile acted as theextractant and the reaction solvent which could not only selectivily extract organosulfur fromdiesel but also enhanced the reactivity of dibenzothiohenes. The proposed approach was ableto desulfurize commercial diesel from1450μg/g to50μg/g, and the sulfur removal reached97%with fuel loss less than1%.The ODS with carbon nanotube as the catalyst under atmospheric pressure and lowtemperature was studied. Results showed that carbon nanotube was an effective catalyst forODS with molecular oxygen as the oxidant, and its catalytic performance was200-fold higherthan Co3O4/γ-Al2O3and MnO2/γ-Al2O3reported in the literature. Raman spectroscopyanalysis revealed that the CNT with the higher degree of graphitization had higher catalyticactivity for DBT oxidation The deactivated CNT can be effectively regenerated by heattreatment under an argon atmosphere at900°C. After five recycling, the activity of carbonnanotube decreased only4%.ODS of jet fuel using in-situ generated peroxides over CuO-ZrO2-TiO2catalyst with airas the oxidant was studied. The generation rate of peroxides was higher over supported CuOcatalyst than bulk CuO. However, over supported CuO catalyst, the induction time for peroxide formation was longer, and the the induction time increased by decreasing the poresize of catalyst. The higher the peroxides concentration was, the higher the sulfur conversionwas. The proposed approach was able to desulfurize jet fuel from485μg/g to25μg/g with theODS conversion of95%.ODS using in-situ generated peroxides in diesel by light-irradiation was proposed. Theinfluencing factors on the peroxides generation and the catalyst activity for ODS in dieselwere studied. Results showed that the kinetics of peroxide generation in diesel could beimproved by the employment of UV irradiation. Accompanying the main ODS reaction withhydroperoxides over MoO3/SiO2catalyst in diesel, the side reaction of peroxideself-decomposition occurred, and the kinetics increased dramatically with the reactiontemperature. To achieve a high ODS conversion, the reaction temperature can be optimizedbalancing the thermodynamics and kinetics of the two coexisting competing pathways ofperoxides. The larger pore size of MoO3/SiO2facilitated the diffusion of bulky refractorysulfur compounds in diesel over the catalyst, and ultimately it led to the increase of sulfurremoval and utilization of peroxides.A new desulfurization approach by photocatalytic oxidation coupled with adsorptionusing bi-functional Ti(1-x)SixO2was proposed. Results showed that over Ti(1-x)SixO2under lightirradiation, organosulfur compounds could be oxidized to sulfoxides, which was furtheradsorbed on Ti(1-x)SixO2. The Ti/Si ratio of Ti(1-x)SixO2was optimized to be3:7to achieve thebest desulfurization performance. The proposed approach was able to desulfurize commercialdiesel from220μg/g to31μg/g under atmospheric pressure and room temperature.更多还原