活性炭用于柴油深度脱硫研究进展

综述了活性炭作为吸附剂和催化剂在柴油深度脱硫方面应用的新进展。通过表面热氧化和负载金属离子对活性炭表面进行化学性能改性,有效提高对柴油中噻吩类硫化物的吸附性能。活性炭作为催化剂,能有效催化过氧化氢和氧化柴油中的噻吩类硫化物而达到催化氧化脱硫。活性炭在柴油深度脱硫方面具有广阔的应用前景,但要真正实现其在脱硫上的工业化应用,尚需加强其表面化学性能改性、再生、吸附和催化氧化机理等方面的研究。     

固体酸催化FCC柴油氧化脱硫

分别采用沉淀-浸渍法制备了SO_4~(2-)/ZrO_2固体酸催化剂,以30%H_2O_2(质量分数)为氧化剂,将FCC柴油中难以脱除的弱极性苯并噻吩(BT)和二苯并噻吩(DBT)类有机硫化物氧化成极性较强的砜和亚砜类物质,再采用极性有机溶剂N,N-二甲基甲酰胺(NMP)进行萃取以脱除氧化后柴油中的砜和亚砜类含硫化合物,最后以脱硫率来评价所制备固体酸的催化脱硫活性和效果.考察了焙烧温度、焙烧时间、硫酸浸渍液浓度等制备条件对固体酸催化脱翩:活性的影响规律.实验结果表明,低温沉淀制备的SO_4~(2-)/ZrO_2固体酸作催化剂时脱硫率较低;高温沉淀制备的SO_4~(2-)/ZrO_2固体酸作催化剂时脱硫率较低,最高脱硫率可达69.2%,回收率可迭97%.     

硫化物在纳米HZSM-5催化剂上催化转化性能及机理研究

研究了催化裂化（FCC）汽油中硫化物类型和含量，特别考察了各种硫化物在纳米HZSM-5催化剂上的催化转化性能，并探讨了硫化物的加氢脱硫转化机理。结果表明FCC汽油中硫化物主要为硫醇、噻吩、烷基取代噻吩和苯并噻吩等，其中，烷基取代噻吩占总硫化物的65％-73％。在纳米HZSM-5催化剂作用下，FCC汽油的硫化物都较易被脱除。烷基取代噻吩脱硫机理一方面含有直接加氢脱硫反应路线，另一方面含有裂解反应、烷基化反应和异构化反应路线。     

废FCC催化剂在LPG吸附脱硫中的资源化利用

金属污染是导致流化催化裂化（FCC）催化剂失活的重要因素,充分利用沉积的重金属是废FCC催化剂资源化的关键。本文将废FCC催化剂引入到轻质油品吸附脱硫领域,以脱除液化石油气（LPG）中的二甲基二硫醚作为考核目标,验证了废FCC催化剂作为脱硫剂的可行性。除去废FCC催化剂表面积炭后,其脱硫性能得到明显改善,在常温、质量空速为4.0h^-1的条件下,LPG中硫化物质量分数从382mg/m³脱除至40mg/m³。镧、铁、镍、钒、钙、锑6种金属在新鲜催化剂和焙烧后废催化剂上的总质量分数从10.2%升高至46.6%,6种金属按照对应含量分别固载在新鲜催化剂上,脱硫效果较未改性新鲜催化剂均有明显提升。验证实验表明,导致FCC催化剂失活的金属具有较高脱硫活性,废FCC催化剂作为轻质油品脱硫剂具备工业前景。     

固体酸催化剂的酸性对噻吩类硫化物转化的影响

在温度300 ℃、空速2.0 h－1条件下,以含有芳烃、烯烃的噻吩类硫化物为模型化合物,探索研究不同酸类型分子筛催化剂硫转化的机理。研究表明,具有不同酸类型的催化剂硫转化效果不同,同时有B酸和L酸的催化剂硫转化效果较好,带侧链的噻吩容易被转化,而且侧链越长、个数越多越容易被吸附脱出。不同酸类型的催化剂对模型化合物的组成影响不同,同时具有B酸和L酸的催化剂使模型化合物中芳烃和烯烃都大量减少,只有L酸的催化剂芳烃会大量减少,而烯烃变化不明显。     

吸附法柴油脱硫技术进展

本文从吸附剂改性、吸附脱硫机理和吸附剂再生等方面综述了以活性炭、金属氧化物、分子筛等为吸附材料吸附脱除柴油中硫化物的最新进展。柴油中的含硫化合物主要包括无机硫和有机硫,其中有机硫占80％以上。在活性炭表面,金属氧化物或分子筛上负载过渡金属都可提高其对硫的吸附能力,π键配位吸附脱硫技术是脱除噻吩类硫化物的有效方法。吸附脱硫是一项具有发展潜力的脱硫技术,然而,要加速这一技术的工业化进程,开发对稠环噻吩类硫化物具有高选择性、高吸附量、易再生的吸附剂是当前面临的重要挑战。     

硫化物在OTA催化剂上催化转化性能

考察了催化裂化(FCC)汽油中硫化物和模型硫化物在OTA(Olefin To Aromatics)催化剂上的催化转化性能.结果表明FCC汽油硫化物总脱硫率为86.3 %,其中,硫醚和四氢噻吩的转化率都达到100 %,硫醇硫转化率96.6 %,噻吩硫转化率78.8 %,烷基噻吩转化率85.8 %,苯并噻吩转化率81.4 %.3-甲基噻吩在OTA催化剂上的转化产物中含有小分子(噻吩),异构硫化物(2-甲基噻吩),以及大分子异构硫化物(如2,5-二甲基噻吩、2,4-二甲基噻吩和2,3-二甲基噻吩).烷基噻吩和苯并噻吩硫化物在OTA催化剂上脱硫反应网络一方面含有直接加氢脱硫反应,另一方面经历歧化、异构化和裂解等反应.     

FCC汽油噻吩烷基化脱硫催化剂研究进展

在简要介绍烷基化脱硫原理基础上,综述了近年来对FCC汽油中噻吩和烷基噻吩等小分子噻吩类硫化合物烷基化反应催化剂的研究进展,着重从分子筛、负载型杂多酸及固体磷酸、离子液体和离子交换树脂等方面来介绍催化裂化汽油烷基化脱硫催化剂的研究应用,最后对汽油烷基化脱硫催化剂的研究重点进行了展望。     

车用燃料油中噻吩类硫化合物脱除技术进展

燃料油硫化物中的噻吩类硫化物较难脱除,采用经济、适用的噻吩类硫化物脱除技术是车用燃料油深度脱硫技术发展的必然趋势。介绍了加氧脱硫、非加氢脱硫、联合脱硫等噻吩类硫脱除技术,指出为了实现高效、经济、环保的目标,联合脱硫技术将得到更多使用,非加氢脱硫技术中的吸附脱硫、氧化脱硫在克服目前存在的技术问题后将有非常好的发展前景。     

Amberlyst树脂催化汽油烷基化硫转移反应的研究

烷基化硫转移反应脱硫是一种非加氧脱硫方法,该法首先利用FCC汽油中的烯烃与噻吩类硫化物进行烷基化反应,形成高沸点的烷基噻吩类硫化物,然后通过蒸馏分离达到脱硫目的.实验分别在FCC汽油和模拟汽油中考察了大孔磺酸树脂Amberlyst 35催化汽油烷基化硫转移的反应活性,并研究了反应温度对反应过程的影响.结果表明 Amberlyst 35树脂可有效催化烷基化硫转移反应的发生,80～140℃温度范围内,在剂油质量比为1:11、反应时间为1 h的条件下,对FCC汽油中主要硫化物的转化率均达到90%以上,可以满足催化精馏烷基化脱硫操作的需要.转化了的烯烃主要发生了低聚反应,随反应温度的升高,烯烃二聚的选择性降低,容易生成更多高沸点胶质,会降低催化剂的稳定性和产品的收率.     

Study on Olefin Alkylation of Thiophenic Sulfur in FCC Gasoline Using La2O3-Modified HY Zeolite

HY zeolite modified by La₂O₃ on olefin alkylation of thiophenic sulfur in fluid catalytic cracking (FCC) gasoline was studied in the micro fixed-bed reactor. Reaction pressure 1.5 MPa, reaction temperature 180 °C, WHSV 3.5 h^?1, using HY zeolite modified by 2% La₂O₃, the conversion of thiophene sulfur promoted nearly 10% with good selectivity, comparing with no-modified by La₂O₃. Acidity of modification of HY zeolite with La₂O₃ was tested in Pyridine–IR, it showed that increasing the amount of weak Bronsted (B) acid and the ratio of total B acid with total Lewis (L) acid could strengthen the hydrogen transfer activity of the catalyst, which leaded to improving the capacity of thiophene alkylation. The X-ray diffraction (XRD) results showed that the structure of catalysts could be optimized by loaded proper amount of La₂O₃ for promoting the acidic properties of HY zeolite.     

Effects of metal modifications of Y zeolites on sulfur reduction performance in fluid catalytic cracking process

The acidity of catalytically active component, e.g., ultra stable Y zeolite (USY), plays an important role in determining their cracking activity and selectivity. To develop advanced sulfur reduction catalytic cracking catalysts, different type of elements were used to modify USY and the resulting catalysts were evaluated in a confined fluidized bed reactor and a micro-activity testing unit. The relation between the acidity of the zeolite and the conversion of sulfur compounds as well as the distributions of fluid catalytic cracking (FCC) products were discussed. The results showed that the rare earth (RE) metal can stabilize the catalyst and increase the conversion, but cannot increase the selectivity to thiophene compounds; V can reduce the sulfur content by 36.3 m%, but decreases the overall conversion compared with the base catalyst. An optimum catalyst was obtained by the combined RE and V modification, over which the sulfur content in FCC gasoline can be decreased and the selectivity for the target products can be improved, with the sulfur content reduced by 30 m% and the selectivity to coke even decreased by 0.20 m% at a comparable conversion level of the base catalyst.     

不同价态钒对重油接触裂化催化剂结构的影响

采用浸渍法在接触裂化催化剂上污染钒,然后进行还原及老化处理,采用TPR和ESR方法表征催化剂上钒的价态,利用BET、XRD方法研究不同价态钒对催化剂结构的影响。结果表明,+5价钒在老化过程中破坏接触裂化催化剂的结构,引起比表面积大幅下降,并导致莫来石相的生成;+4价钒对接触裂化催化剂结构的影响不大。     

Some ideas on cracking catalyst design

Progress in understanding the nature of cracking catalysts has led from the early recognition of the carbonium ion intermediate to the current view which ascribes cracking activity to the acidic nature of active sites. Here we develop the concept of acid catalysis to include the specific effects of Bronsted and Lewis acid sites on gas oil cracking. It is shown that these two types of sites react with specific substrates and that each has a characteristic kinetic behaviour. This leads us to suggest that careful control of the total site density and of the proportion of Bronsted/Lewis sites can result in a catalyst which is optimized for the feedstock, reactor configuration, and product distribution desired.     

Chemistry, spectroscopy and the role of supported vanadium oxides in heterogeneous catalysis

Supported vanadium oxide catalysts are active in a wide range of applications. In this review, an overview is given of the current knowledge available about vanadium oxide-based catalysts. The review starts with the importance of vanadium in heterogeneous catalysis, a discussion of the molecular structure of vanadium in water and in the solid state and an overview of the spectroscopic techniques enabling to study the chemistry of supported vanadium oxides. In the second part, it will be shown that advanced spectroscopic tools can be used to obtain detailed information about the coordination environment and oxidation state of vanadium oxides during each stage of the life-span of a heterogeneous catalyst. Three topics will be discussed: (1) the molecular structure of supported vanadium oxide catalysts under hydrated, dehydrated and reduced conditions, including the parameters, which influence the molecular structures formed at the surface of the support oxide; (2) elucidation of the active surface vanadium oxide during the oxidation of methanol to formaldehyde, the reaction mechanism and the vanadium oxide---support effect; and (3) deactivation of fluid catalytic cracking (FCC) catalysts by migration of vanadium oxides and the development of a method preventing the structural breakdown of zeolites by trapping the mobile vanadium oxides in an aluminum oxide coating.     

Interaction of vanadium and nickel porphyrins with catalysts, relevance to catalytic demetallisation

The binding of vanadium and nickel porphyrins to γ-Al₂O₃, SiO₂-Al₂O₃ MoO₃/Al₂O₃, NiO/Al₂O₃, and to Co- and Ni-Mo/Al₂O₃ catalysts in their oxide and sulfide forms, and their subsequent decomposition reactions when heated in nitrogen or exposed to hydrogen and thiophene in catalytic hydrodesulfurisation, have been studied by electron spin resonance. We wished to discover which part of the porphyrin molecule became bound to the catalyst and to which surface sites. Our main conclusions are that the porphyrins are bound to the catalyst by a donor-acceptor interaction,, the delocalised π-system of the porphyrin ring being the electron donor, and the Bronsted and/or Lewis acid function of the catalyst being the acceptor. Depending on the conditions, oxidation or hydrogenation of the porphyrin ring at the meso carbons is the initial stage in the decomposition of the bound porphyrins.     

Fluid catalytic cracking technology: current status and recent discoveries on catalyst contamination

The fluid catalytic cracking (FCC) technology is one of the pillars of the modern petroleum industry which converts the crude oil fractions into many commodity fuels and platform chemicals, such as gasoline. Although the FCC field is quite mature, the research scope is still enormous due to changing FCC feedstock, gradual shifts in market demands and evolved unit operations. In this review, we have described the current status of FCC technology, such as variation in the present day feedstocks and catalysts, and particularly, great attention is paid to the effects of various contaminants of the FCC catalysts of which the latter part has not been sufficiently documented and analyzed in the literature yet. Deposition of various contaminants on cracking catalyst during FCC process, including metals, sulfur, nitrogen and coke originated from feedstocks or generated during FCC reaction constitutes a source of concern to the petroleum refiners from both economic and technological perspectives. It causes not only undesirable effects on the catalysts themselves, but also reduction in catalytic activity and changes in product distribution of the FCC reactions, translating into economic losses. The metal contaminants (vanadium (V), nickel (Ni), iron (Fe) and sodium (Na)) have the most adverse effects that can seriously influence the catalyst structure and performance. Although nitrogen and sulfur are considered less harmful compared to the metal contaminants, it is shown that pore blockage by the coking effect of sulfur and acid sites neutralization by nitrogen are serious problems too. Most recent studies on the deactivation of FCC catalysts at single particle level have provided an in-depth understanding of the deactivation mechanisms. This work will provide the readers with a comprehensive understanding of the current status, related problems and most recent progress made in the FCC technology, and also will deepen insights into the catalyst deactivation mechanisms caused by contaminants and the possible technical approaches to controlling catalyst deactivation problems.     

流化催化裂化汽油吸附脱硫金属氧化物吸附剂

制备了不同的金属氧化物吸附剂并采用不同方法进行改性,在常压、温度为360℃、液时空速为1 h-1的条件下,采用固定床吸附法考察了吸附剂改性前后的脱硫性能.结果表明:MoO3和MnO2的脱硫效果较好,对硫含量为511.10 μg/g的流化催化裂化(FCC)汽油脱硫,脱硫率达60%以上;CuO-MoO3,MoO3-MgO和MoO3-Fe2O3复合金属氧化物吸附剂对FCC汽油的脱硫效果可达75%以上,其中脱除乙硫醇效果最好的是CuO-MoO3,脱除噻吩效果最好的是MoO3-MgO,脱除二苯并噻吩效果最好的是MoO3-Fe2O3;采用等体积浸渍法对MoO3和MnO2改性后,对FCC汽油吸附脱硫效果有所增强,其中对MoO3改性效果较好的是NiO,脱硫率可达90.1%,对MnO2改性效果较好的是CoO,脱硫率可达93.2%.