中孔硅胶负载浓硝酸脱除柴油中的硫化物

采取中孔硅胶负载浓硝酸脱除1 000×10~(-6)的4,6-二甲基二苯并噻吩模型柴油中的硫化物,考察反应温度、酸负载量、剂油质量比和吸附剂目数对脱硫效果的影响,并通过红外光谱分析和N_2等温吸附法对硅胶进行表征。结果表明,中孔硅胶具有较大的比表面积、孔体积和合适的孔径;浓硝酸可以负载于中孔硅胶上并将4,6-二甲基二苯并噻吩氧化为砜后吸附在硅胶上。在反应温度45℃、(40~60)目硅胶和硅胶与浓硝酸质量比为1∶0.75条件下脱硫效果最好,剂油质量比为1∶7.5时,脱硫率达93.7%,脱硫后的模型柴油硫含量达到国Ⅴ标准。     

氧化吸附法脱除燃油中苯并噻吩类硫化物

为深度脱除燃油中苯并噻吩类硫化物,采用质量分数69.8%浓硝酸作为催化剂和氧化剂,负载于硅胶吸附剂孔中制备成脱硫剂,在间歇反应器中,常温常压操作条件下处理质量分数1 000×10-6 4,6-二甲基二苯并噻吩(4,6-DMDBT)模型油.结果显示:脱硫剂在温度45 ℃,吸附剂与催化剂负载质量比1: 0.75,吸附剂与燃...     

金属离子改性HY-KIT-1脱除柴油中硫化物

以介孔分子筛KIT-1与微孔分子筛HY机械混合作为载体,负载活性组分Ce、Ni、Co,对柴油中的含硫化合物进行吸附分离,采用气相色谱-硫化学发光检测分析柴油脱硫前后噻吩类硫化物的分布.结果表明,柴油中所含的硫化物主要为苯并噻吩和二苯并噻吩,其中苯并噻吩占总含量的51.15％,二苯并噻吩占总含量的48.85％.Ce/HY-KIT-1吸附剂的吸附效果最好.     

柴油加氢脱硫机理的研究进展

从常规加氢脱硫（HDS）到超深度HDS（S〈10μg/g）的转变面临着非常复杂的技术问题。一些硫化物（4,6-二甲基二苯并噻吩等）在常规脱硫条件下很难脱除。在超低硫柴油的生产过程中,这类硫化物也必须脱除。文章对柴油加氢脱硫机理进行了综述。     

分级多孔HPW/TiO_2催化剂的合成及其氧化脱硫性能

以阳离子表面活性剂(CTAB)为介孔模板,单分散聚苯乙烯微球(PS)为大孔模板,合成了一系列分级孔磷钨酸(HPW)/TiO_2复合材料,并将其用于燃油深度氧化脱硫。采用X-射线衍射、氮气吸脱附、扫描电镜、红外光谱及紫外光谱等技术对催化剂的结构及形貌进行表征。结果表明,该催化剂具有无序大孔、有序介孔的结构,Keggin型结构HPW高度分散在TiO_2基质中。在优化的反应条件下,该催化剂对苯并噻吩(BT)、二苯并噻吩(DBT)、4,6-二甲基二苯并噻吩(4,6-DMDBT)的脱除率分别达到100%、82%和86%。由于该催化剂的分级孔结构缩短了介孔的传输距离,同时催化剂的高比表面积使得更多的活性中心位点暴露,因此提高了催化剂的催化氧化脱硫性能。此外催化剂循环使用5次后性能仅稍微降低。     

柴油深度脱硫技术研究进展

加氢柴油中残留的硫化物主要为二苯并噻吩及其衍生物,因此,脱除柴油中二苯并噻吩类硫化物是实现柴油深度脱硫的关键技术。系统地介绍了加氢脱硫、生物脱硫、氧化脱硫和吸附脱硫等技术及其优缺点,重点介绍了反应吸附脱硫技术的最新研究进展。     

柴油吸附脱硫工艺条件影响

研究了吸附工艺条件对柴油中硫化物,特别是对二苯并噻吩（DBT）的脱除效果。实验在常压下,采用静态吸附法,以FCC柴油和DBT模型物为原料,用燃灯法测定脱硫前后油品的硫含量,考察了模型物溶剂、油品中含有的芳烃以及吸附温度对吸附剂脱硫率的影响。得出溶剂黏度越大吸附脱硫率越差;油品中含有芳烃时,吸附剂脱硫率减小,温度对脱硫率的影响不大。考察了高温氮气、有机溶剂和水蒸汽这3种再生方法对吸附剂的再生效果,结果表明,水蒸汽600℃再生4h和有机溶剂苯洗涤24h的再生效果较好,基本可以恢复吸附剂的吸附性能。     

吸附法脱除柴油中噻吩类含硫化合物的研究进展

综述了吸附法脱除柴油中噻吩类含硫化合物的常用吸附剂、吸附脱硫的机理及吸附脱硫过程动力学研究的最新进展。阐述了近来研究较多的吸附剂主要有分子筛、活性炭和金属有机骨架（MOFs）材料。目前传统的加氢脱硫（HDS）技术虽然可以满足当前柴油中硫含量的国家标准,但是其需要高温高压、成本高且对二苯并噻吩类硫化物脱硫率低,而吸附脱硫技术由于成本低、操作条件温和、易脱除加氢脱硫难以脱除的硫化物、对油品品质影响小等优点成为当前柴油脱硫的研究热点。吸附脱硫主要包括反应型吸附脱硫和非反应型吸附脱硫,反应吸附脱硫关键是有旧键的断裂与新键的生成,而非反应吸附脱硫则是通过分散力使硫化物上的硫原子与吸附剂之间相互作用,从而达到吸附脱硫的作用。本文对吸附脱硫机理和吸附脱硫过程的动力学加以讨论,为以后的研究提供一定的理论基础,并提出了脱硫吸附剂今后的研究方向。     

柴油深度脱硫三集总一级动力学模型建立

将柴油馏分中硫化物按照其加氢脱硫反应难易程度分为三个集总,建立了柴油深度加氢脱硫反应三集总一级动力学模型。运用建立的动力学模型对柴油馏分中不同类型硫化物的反应规律以及工业上几种不同类型柴油加氢脱硫催化剂的反应性能特点进行了分析。动力学模型拟合结果表明,在脱硫率为70%时,集总1已经完全脱除,生成油中剩余未转化硫化物全部为集总2和3硫化物,且随着反应深度的加深集总3的比例逐渐提高,脱硫率达到98%后,加氢精制油剩余硫化物80%以上为集总3硫化物,4,6位含空间位阻作用的二苯并噻吩(DBT)硫化物的脱除是深度脱硫反应过程的速率控制步骤。相比于另外两个集总硫化物,集总3的脱除反应提温敏感性较差,较高的压力和较低的空速下有利于这部分硫化物的脱除。运转评价结果也表明催化剂1相比于催化剂2和3在深度加氢脱硫反应过程受热力学平衡限制作用更加明显:以原料2为反应进料,在反应压力6.0 MPa、体积空速1.0 h-1条件下催化剂1加氢脱硫生成油硫含量随反应温度变化曲线在370℃下出现拐点。而在相同压力、体积空速1.5 h-1条件下,催化剂2和3上随着反应温度的升高,产品硫含量逐渐降低,在试验的温度范围内,未出现温度拐点。催化剂2和3表现出了更好的对集总3的脱除效率以及更好的提温敏感性,更适合工业装置上深度脱硫反应过程。     

ZrO2/SiO2催化剂的制备及其氧化脱硫性能研究

以己内酰胺-八水氧氯化锆低共熔溶剂为添加组分,采用溶胶-凝胶法合成含锆的硅胶,再经过高温煅烧得到n-ZrO₂/SiO₂ （n=2%,4%,6%） 负载型催化剂。并用红外光谱（FT-IR）、X射线衍射（XRD）、扫描电镜（SEM）、N₂吸附-脱附、X射线光电子能谱（XPS）对其进行结构表征,确定ZrO₂成功负载到SiO₂上。以ZrO₂/SiO₂为催化剂和吸附剂,H₂O₂为氧化剂组成催化氧化脱硫体系,并应用于模拟油脱硫。分别考察了氧化锆负载量、反应温度、氧硫比、催化剂加入量及不同类型的硫化物对脱硫效果的影响。实验结果表明,在反应温度为70℃、n（H₂O₂）/n（S）=4（摩尔比）、4%-ZrO₂/SiO₂的加入量为0.2 g的最佳反应条件下,氧化脱硫体系对二苯并噻吩（DBT）、4,6-二甲基二苯并噻吩（4,6-DMDBT）和苯并噻吩（BT）的脱除率分别为98.7%、93%和65.9%。且4%-ZrO₂/SiO₂回收利用5次后,DBT脱除率仍可达到91.8%。     

Performance of fluorine-added CoMoS/Al2O3 prepared by sonochemical and chemical vapor deposition methods in the hydrodesulfurization of dibenzothiophene and 4,6-dimethyldibenzothiophene

The performance of a new type of CoMoS/Al₂O₃ catalyst, with added fluorine and prepared by sonochemical and chemical vapor deposition (CVD) methods, was investigated in the hydrodesulfurization (HDS) of dibenzothiophene (DBT) and 4,6-dimethyldibenzothiophene (4,6-DMDBT). The catalyst, which was designed to contain optimum amounts of fluorine and cobalt, exhibited a higher activity, ca. 4.6 times higher activity particularly in the HDS of 4,6-DMDBT, than a fluorine-free catalyst prepared by a conventional impregnation method. The enhanced activity of the new catalyst can be attributed to the cumulative effects of individual factors involved in the catalyst preparation. That is, the use of a sonochemical synthesis led to a high dispersion of small MoS₂ crystallites on the alumina, and the addition of the Co species to the catalyst by CVD caused a close interaction between the Co species and the MoS₂ crystallites to produce numerous CoMoS species, which are the catalytically active species for HDS. The addition of fluorine increased the amounts of acidic sites in the catalyst, which promoted hydrogenation (HYD) route to a greater extent than the direct desulfurization (DDS) route in DBT HDS and both HYD and DDS routes to similar extents in the case of 4,6-DMDBT HDS. Accordingly, the addition of fluorine led to a greater increase in catalytic activity for 4,6-DMDBT HDS than for DBT HDS.     

Microbial desulfurization of dibenzothiophene and 4,6-dimethyldibenzothiophene in dodecane and straight-run diesel oil

The desulfurization of dibenzothiophene (DBT), 4,6-dimethyldibenzothiophene (4,6-DMDBT) and their mixture by lyophilized cells ofPseudomonas delafieldii R-8 was studied in the presence of dodecane. The desulfurization rate for 4,6-DMDBT was found to be about 40% in comparison with that for DBT. The desulfurization process for DBT and 4,6-DMDBT proceeded simultaneously without preference for either one. The desulfurization rate for each compound was decreased when they were mixed together. The extent of desulfurization of 4,6-DMDBT was increased with the increase of cell concentration and the decrease of the volume ratio of oil-to-water used. The specific desulfurization rate for 4,6-DMDBT could be reached to 10.4 mmol sulfur kg⁻¹ (cell) h⁻¹ [approximately 0.33 mg sulfur g⁻¹ (cell) h⁻¹].Pseudomonas delafieldii R-8 showed high desulfurization capability for straight-run diesel oil (containing 1,807 mg/L of sulfur). About 1,000 mg/L of sulfur in diesel oil was removed by resting cells of this strain in 24 h of reaction. The specific desulfurization rate was 8.75 mmol sulfur kg⁻¹ (cell) h⁻¹.     

Hydrodesulfurization of hindered dibenzothiophenes on bifunctional NiMo catalysts supported on zeolite–alumina composites

A series of NiMo catalysts supported on HNaY(x)–Al₂O₃ composites with different amounts of HNaY zeolite (x = 0, 5, 10, 20 and 100 wt.% of HNaY) was prepared and tested in the hydrodesulfurization (HDS) of dibenzothiophene (DBT) and 4,6-dimethyl-DBT (4,6-DMDBT). The catalysts were characterized by N₂ physisorption, X-ray diffraction (XRD), FT-IR spectroscopy of pyridine and nitrogen oxide adsorption (Py and NO-FT-IR), temperature-programmed reduction (TPR), scanning electron microscopy (SEM-EDX) and high-resolution transmission electron microscopy (HRTEM). It was found that the increase in the zeolite content causes changes in the acidic properties of the catalyst (number of acid sites) as well as in the characteristics of the deposited metallic species (location and dispersion). Different activity trends with the amount of the zeolite were found for the DBT and 4,6-DMDBT hydrodesulfurization on NiMo/HNaY-Al₂O₃ catalysts. As for the HDS of DBT the alumina-supported catalyst presents the highest activity. The incorporation of the zeolite causes an initial drop and then the recovery of activity with zeolite content. In contrast, for the 4,6-DMDBT the HDS activity always increases with zeolite content. These two different catalytic behaviors seem to be due to two opposite effects, which affect the contribution of the reaction routes available for the HDS of each reactant, these effects are: (i) the decrease of MoS₂ dispersion caused by the incorporation of zeolite to the catalyst and (ii) the increase of the proportion of Brönsted acid sites with zeolite content. The reaction product distribution indicates that both types of sites, coordinatively unsaturated sites (CUS) of the MoS₂ and zeolite Brönsted acid sites, participate in the 4,6-DMDBT and DBT transformations.     

苯深度脱硫钌吸附剂失活及其原因分析

从吸附剂中活性组分钌的烧结、流失、氧化、中毒四个方面分析苯吸附脱硫钌吸附剂的失活原因,总结吸附剂的失活机制。以运行后的苯吸附脱硫钌吸附剂和新鲜吸附剂为研究对象,应用氮气吸附-脱附、X射线衍射、X射线荧光、透射电镜等手段对新鲜吸附剂及运行后吸附剂进行表征。结果表明,活性组分钌未出现明显流失,同时晶粒没有出现团聚,吸附剂表面孔结构变化、Fe和Cl中毒是其硫容降低的主要原因。吸附剂再生后,硫容约恢复到初始硫容的90%。     

柴油深度加氢脱硫技术进展

随着世界各国对环保法规的日益关注,运输燃料深度脱硫技术在世界范围内受到广泛的研究。近年来,柴油深度脱硫化技术已受到西方国家的普遍重视。在工业上,加氢工艺是应对产品低硫化最有效的途径。柴油深度脱硫的关键是对反应活性最低的4,6-二甲基苯并噻吩类化合物中硫原子的脱除。本文综述了近年来柴油深度加氢脱硫技术的基本原理、超低硫柴油的催化及工艺的研究进展。     

MCM-41-supported Co-Mo catalysts for deep hydrodesulfurization of light cycle oil

Light cycle oil (LCO), a by-product of the fluid catalytic cracking (FCC) process in a petroleum refinery, can be used as a blendstock for the production of diesel and jet fuels. Regulatory and operational issues result in need for new and more active catalysts for the deep hydrodesulfurization (HDS) of diesel feedstocks, such as LCO. This paper reports the activity of a mesoporous molecular sieve MCM-41-supported Co-Mo catalyst in comparison to a commercial γ-alumina (Al₂O₃)-supported Co-Mo catalyst for the desulfurization of a LCO with a sulfur content of 2.19 wt.%. The HDS of dibenzothiophene, 4-methyldibenzothiophene, and 4,6-dimethyldibenzothiophene—polyaromatic sulfur compounds present in LCO—and their relative reactivities in terms of conversion were examined as a function of time on stream in a fixed-bed flow reactor. The MCM-41-supported catalyst demonstrates consistently higher activity for the HDS of the refractory dibenzothiophenic sulfur compounds, particularly 4,6-dimethyldibenzothiophene. The presence of a large concentration of aromatics in LCO appears to inhibit the HDS of the substituted dibenzothiophenes.     

MoO2/g-C3N4催化剂的制备及其氧化脱除模拟油中的硫化物

采用高温煅烧MoO₂和g-C₃N₄混合物制备了不同MoO₂含量的MoO₂/g-C₃N₄催化剂。采用X射线粉末衍射（XRD）、傅里叶红外光谱（FTIR）、扫描电镜（SEM）和N₂吸附脱附对催化剂的结构和性能进行了表征。以MoO₂/g-C₃N₄作为催化剂,H₂O₂为氧化剂,离子液体为萃取剂研究了反应体系的氧化脱硫性能。这项研究中考察了不同煅烧温度下制得的催化剂、负载量、氧化剂使用量、催化剂加入量、反应温度、萃取剂使用量、反应时间、硫化物类型等不同反应参数对脱硫率的影响。结果表明,在H₂O₂的使用量为0.2mL,MoO₂/g-C₃N₄加入量为0.03g,1-乙基-3-甲基咪唑硫酸乙酯离子液体1.0mL,反应温度为70℃,反应时间60min的最佳工艺条件下,24%-MoO₂/g-C₃N₄催化剂脱硫率可以达到94.8%,催化剂循环使用5次后活性没有明显下降。此外,研究了MoO₂/g-C₃N₄在离子液体中的催化氧化反应机理。