FCC汽油降烯烃工艺及催化剂研究进展

针对国VI汽油标准大幅度降烯烃的需要及乙醇汽油对有机含氧化合物含量的严格要求,从分子炼油角度出发,按照烯烃碳数C_4、C_5～C_6、C_5～C_8的顺序分别介绍并分析催化裂化(FCC)汽油降烯烃后处理技术,包括MTBE生产、烷基化、醚化、异构化/芳构化工艺发展状况、优缺点与应用局限。由于乙醇汽油的推广,MTBE生产技术与轻汽油醚化技术将面临停产的困境与改造的挑战,而烷基化、异构化/芳构化等生产高辛烷值汽油组分的技术是更具潜力的FCC汽油降烯烃技术,将得到大力发展。此外,总结常用工业催化剂及其改性研究,并简述存在问题与发展方向,提出汽油组分比例优化、MTBE装置改造等建议与展望,为FCC汽油降烯烃工艺技术路线选择提供借鉴。     

碳四烃转化与利用技术研究进展及发展前景

我国来自炼油厂和石化装置的碳四(C₄)烃资源非常丰富,与此同时,C₄烃用作传统液化石油气燃气的需求量正逐渐减少,C₄烃资源综合利用成为企业的关注热点。本文介绍了国内外C₄烃转化与利用技术的开发进展及工业应用情况,包括丁烯异构化、丁烯歧化、C₄烯烃催化裂解、异丁烷脱氢、异丁烯制甲基丙烯酸甲酯(MMA)、C₄烃芳构化与烷基化等。认为对炼化一体化企业而言,将炼油厂C₄和裂解C₄整合在一起,应用增产低碳烯烃、醚后C₄生产高辛烷值汽油组分、C₄组分相互转化以及向下游高附加值产品延伸等技术,未来将具有较好的发展前景,不仅可为市场提供所需的燃料与化学品,而且有利于提升企业经济效益。     

劣质原料催化裂化脱硫降烯烃生产清洁汽油技术

介绍了劣质催化裂化原料的特点,分析了催化裂化汽油清洁化对策,应从提高FCC汽油质量关键应从FCC进料预处理、优化FCC加工过程以及FCC汽油精制等3方面出发．采用有效的降烯烃技术以及选择性加氢和氧化一萃取等脱硫技术对催化裂化汽油进行清洁化处理。认为应注重发展加氢技术,增强加氢在清洁油品生产中的作用;适当减少FCC汽油所占比例,增加异构化油、烷基化油、重整汽油比例,缩小与国外成品油结构组成的差距。     

催化裂化汽油降烯烃技术研究进展

从FCC技术、醚化改质技术、芳构化改质技术等方面介绍了催化裂化汽油降烯烃技术的发展状况。对FCC自身进行改造的方法简单易行;轻汽油醚化和芳构化改质技术不仅降低了汽油的烯烃含量,同时可以大大提高汽油的辛烷值,但汽油中醚类及芳烃的含量都有一定的限制。目前要降低汽油烯烃含量,需要发展一整套综合技术或措施,然而要从根本上解决问题,必须对汽油的生产结构进行调整,降低催化裂化汽油的比重,增加烷基化、异构化、芳构化、重整等汽油的比例。     

ZSM-5/γ-Al2O3质量比对FCC轻汽油异构化/芳构化性能影响

通过调变ZSM-5分子筛与γ-Al₂O₃质量比,采用等体积浸渍法制备系列FCC轻汽油异构化/芳构化催化剂。本文采用X射线衍射（XRD）、N₂吸附脱附、扫描电子显微镜（SEM）、氨气程序升温脱附（NH₃-TPD）、红外光谱（IR）和吡啶红外光谱（Py-IR）等手段对其进行表征,并以乌鲁木齐石化醚后C₅掺杂液化石油气（LPG）为原料对催化剂异构化/芳构化性能进行评价。实验结果表明,ZSM-5分子筛与γ-Al₂O₃质量比的调变可以改变催化剂的酸性质及孔结构性质。在反应温度380℃、反应压力1.0MPa、反应空速1.0h^-1、氢/油体积比100、LPG进量4.4g/h的条件下,ZnLa/ZSM-5/γ-Al₂O₃-1异构化/芳构化产物与反应原料相比,烯烃体积分数降低27.49%、异构烷烃体积分数增加15.87%、芳烃体积分数增加3.97%,辛烷值损失3.38个单位,产品收率高达89.90%,实现了异构化/芳构化大幅降烯烃保辛烷值的目标。     

Catalytic conversion of commingled polymer waste into chemicals and fuels over spent FCC commercial catalyst in a fluidised-bed reactor

A commingled post-consumer polymer (CPW#1) was pyrolysed over spent fluid catalytic cracking (FCC) commercial catalyst (ECat-1) using a laboratory fluidised-bed reactor operating isothermally at ambient pressure. The influence of reaction conditions including catalyst, temperature, ratios of commingled polymer to catalyst feed and flow rates of fluidising gas was examined. The conversion for spent FCC commercial catalyst (82.7 wt%) gave much higher yield than silicate (only 14.2 wt%) and the highest yield (nearly 87 wt%) was obtained for ZSM-5. Greater product selectivity was observed with ECat-1 as a recycled catalyst with about 56 wt% olefins products in the C₃–C₇ range. The selectivity could be further influenced by changes in reaction conditions. Valuable hydrocarbons of olefins and iso-olefins were produced by low temperatures and short contact times used in this study. It is also demonstrated that the use of spent FCC commercial catalyst and under appropriate reaction conditions can have the ability to control both the product yield and product distribution from polymer degradation, potentially leading to a cheaper process with more valuable products.     

Efficient production of propylene and gasoline from methanol in multi-regime riser

High gas-solid contact efficiency and low solid back-mixing are necessary to both promote methanol conversion and inhibit side reactions. Thus, a novel multi-regime reactor with dense-phase reaction section and dilute-phase conveying region was designed. The reactor promoted stable reaction activity during a 300 h pilot-scale evaluation with high yields of propylene and gasoline. A process for maximum propylene and gasoline production from methanol (PGFM) characterized by moderate operating severity, application of ZSM-11 catalyst and novel reactor, and stratified reprocessing or etherification of light gasoline and C₄ olefins was proposed. The PGFM process can be implemented in the existing FCC process and is considered to be more economic and flexible.     

Conversion of waste plastics into fuels: Recycling polyethylene in FCC

Low density polyethylene was dissolved into toluene and converted at 500 °C over three different commercial FCC catalysts in a laboratory Riser Simulator reactor. Short reaction-times up to 12 s were used. All the catalysts had qualitatively similar behaviors. The specific contribution of the polymer to the product slate of FCC was centered in hydrocarbons in the range of gasoline, with high aromatic content and highly olefinic C₃–C₄ gases. Saturated C₄–C₅ products were mainly isoparaffins. The additional coke formed by the polymer would make coke yields to increase moderately in relation to the standard operation. These facts confirmed that this recycling option, which is based on a proven technology, represents an interesting alternative to solve a major environmental problem.     

Reactivity of olefins in the hydrodesulfurization of FCC gasoline over CoMo sulfide catalyst

To achieve selective hydrodesulfurization (HDS) of fluid catalytic-cracked (FCC) gasoline for producing sulfur-free gasoline (S < 10 ppm), the reactivity of various olefins contained in FCC gasoline on CoMoP/Al₂O₃ sulfide catalysts was investigated. Isomerization of the CC double bond from the terminal position to an internal position was observed. The steric hindrance around the CC double bond suppresses the reactivity of olefin hydrogenation. The sulfidation temperature of the catalyst has a major influence on olefin hydrogenation active sites. Addition of the appropriate amount of cobalt (Co/Mo ratio approximately 0.6) contributes to the suppression of olefin hydrogenation at high reaction temperature (260 °C). From the comparison of catalytic performance and characterization of our CoMoP/Al₂O₃ catalyst with an analogous commercial catalyst, it is suggested that the hydrogenation of olefins depends not only on the state of the Mo CUS but also on the steric effects of both olefin structure and MoS₂ crystalline structure.     

新时期C4馏分中异丁烯综合利用分析

随着国家对生物燃料乙醇生产和推广使用车用乙醇汽油的方案实施,C_4馏分中异丁烯的利用引起科研工作者和石油炼制行业的思考。我国C_4资源利用尤其是异丁烯一直以来主要依靠甲基叔丁基醚(MTBE)生产路线,其中,90%用于汽油辛烷值添加剂。汽车能源清洁化是新能源发展必由之路,我国的能源结构正在经历前所未有的全面重构,如何应对逐渐步入的乙醇汽油时代?如何满足汽油的清洁绿色性能?异丁烯等C_4资源如何重新布局?这些成为各石油化工企业的很难面对又不得不面对的困惑。着重介绍可改造或代替MTBE生产过程,为C_4资源尤其是异丁烯的综合利用提供出路的主要技术,并对不同技术进行工艺特点、产品性质与市场应用等方面的分析,为市场应对新时期清洁燃料等需求提供借鉴与帮助。     

Chemistry, Catalysts, and Processes for Isoparaffin-Olefin Alkylation: Actual Situation and Future Trends

As a consequence of the Clean Air Act (CAA), beginning in 1990, USA refiners were forced to change their strategy in order to meet the new mandatory specifications on gasoline composition. The targets established by the CAA were directed to overcoming environmental problems by reducing the ground-level ozone-forming and carbon monoxide emissions from vehicles, as well as toxic hydrocarbons and SO, and NO, emissions in auto exhausts. In order to accomplish this, gasolines had to move in the following direction:

1. Reduce volatility: that is, lower Reid vapor pressure (RVP), especially during summer months, in order to reduce ozone levels. This can be achieved by removing butanes and even C, from the gasoline.
2. Limitations in the aromatic content, with special emphasis on benzene. This can be solved by reducing reformate severity and/or by reducing the upper cut of the fluid catalytically cracked (FCC) gas-oline.
3. Increased amount ofoxygenates, in which MTBE and TAME are preferred, especially in the carbon monoxide and ozone nonattainment areas.
4. Reduction of olefins: This will be achieved by separating the C, olefins from FCC gasoline. Meanwhile, the elimination of C, olefins from the gasoline will further reduce RVP, and the isoamylenes will be used as a raw material to produce TAME in sterification units.
5. Reduction of sulfur: Hydrotreating of FCC feeds, or hydrotreating or removing part of the heavy-end FCC gasoline.
6. Elimination of lead: This, which was already under way when the new regulations were announced, produces a decrease in octane which has to be compensated by other streams coming into the gasoline pool.

     

CO/CO2加氢高选择性合成化学品和液体燃料

一氧化碳/二氧化碳（CO/CO₂）转化利用是碳一化学与CO₂捕集利用中的重要环节,也是当今碳资源的非石油路线利用最具挑战性的方向之一。CO₂的高效活化与定向转化是CO₂利用过程中的关键问题,而CO加氢转化最大的瓶颈问题为如何有效控制C-O键的活化、C—C键的形成、碳链增长及终止。本文主要综述 CO/CO₂加氢高选择性合成重要化工原料低碳烯烃（C₂ ⁼～C₄ ⁼）以及一步高效合成汽油馏分（C₅～C₁₁）等方面取得的突破性进展。目前,CO/CO₂加氢主要经过费托合成与氧化物/分子筛双功能两条路线合成低碳烯烃与汽油燃料。针对费托合成C₂ ⁼～C₄ ⁼,分析表明棱柱状碳化钴得到的烃类产物分布可以显著突破Anderson-Schulz-Flory（ASF）分布的限制,而分子筛已被广泛用于构建双功能费托催化剂,由于酸性分子筛具有加氢裂化、低聚与异构化等功能,使得CO/CO₂还可以直接高选择性地转化为C₅～C₁₁烃类。另一方面,将可以活化CO或CO₂到甲醇的可还原型氧化物与具有C—C偶联功能的SAPO-34或HZSM-5分子筛进行耦合,也可以实现CO/CO₂加氢一步合成低碳烯烃或汽油且具有非常优异的选择性和高转化率。今后,借鉴纳米合成领域新方法,使产物分布打破经典ASF限制,最大限度地提高目标烃类化合物的选择性并显著减少甲烷的生成是研究关键。     

液化气C4组分异构化研究及应用

在实际生产过程中,MTBE装置加工后的剩余C₄中含有大量非活性C₄烯烃,该部分烯烃随着液化气作为产品进行销售,对于液化气中的C₄造成浪费。提出将MTBE装置剩余C₄引入汽油加氢醚化装置异构化反应器进行异构化反应,将剩余C₄中的非活性烯烃转化为活性烯烃,再将异构化产物送至MTBE装置原料缓冲罐中作为MTBE装置原料进行反应。通过调研后得出,异构化反应器催化剂对剩余C₄中的非活性烯烃转化率可达30%,异构化反应产物与进料对比,异丁烯含量上升约3%,可有效提高MTBE装置产品产量。     

The performance of solid phosphoric acid catalysts and macroporous sulfonic resins on gasoline alkylation desulfurization

Sulfur removal has received increasing attention in recent years primarily for environmental protection purpose. As an attractive technology in the case of gasoline, OATS (olefinic alkylation of thiophenic sulfur) proposed to separate sulfur compounds by distillation after being weighed down by alkylation with olefins in the feed. In this paper, alkylation reactions of thiophenic compounds were studied over solid phosphoric acid catalysts (SPAM and SPAS using MCM-41 and Silicalite-1 zeolite as supporters respectively) and macroporous sulfonic resins (including NKC-9, D005-2 and Amberlyst 35) with model gasoline and FCC (fluid catalytic cracking) gasoline. Results showed that macroporous sulfonic resins showed better performance than solid phosphoric acid catalysts under milder conditions in both feeds. Among the resins, Amberlyst 35 was the most suitable catalyst for the application of catalytic distillation for its good performance at the temperature range of 353-413 K in FCC gasoline. However, the selectivity of isoamylene dimerization over Amberlyst 35 decreased with the temperature, which was harmful to the product yield and catalyst stability. Besides, different activity orders of solid phosphoric acid catalysts in model gasoline and FCC gasoline were explained by combining the acidic properties of the catalysts with the species of olefins in two feeds.     

Study on reformulation of fluid catalytic cracking gasoline and increasing production of light olefins

The effects of reaction temperature, mass ratio of catalyst to oil, space velocity, and mass ratio of water to oil on the product distribution, the yields of light olefins (light olefins including ethylene, propylene and butylene) and the composition of the fluid catalytic cracking (FCC) gasoline upgraded over the self-made catalyst GL in a confined fluidized bed reactor were investigated. The experimental results showed that FCC gasoline was obviously reformulated under appropriate reaction conditions. The olefins (olefins with C atom number above 4) content of FCC gasoline was markedly reduced, and the aromatics content and octane number were increased. The upgraded gasoline met the new standard of gasoline, and meanwhile, higher yields of light olefins were obtained. Furthermore, higher reaction temperature, higher mass ratio of catalyst to oil, higher mass ratio of water to oil, and lower space velocity were found to be beneficial to FCC gasoline reformulation and light olefins production.     

ZSM-5分子筛的复合改性及催化裂化性能

针对催化裂化反应中提高汽油辛烷值和增加丙烯收率，对择形分子筛ZSM-5的改性方法进行研究。通过磷、钴和稀土的复合改性，不仅提高改性元素磷的利用率，而且加强分子筛裂化汽油中C₅、C₆烯烃以及异构化和芳构化能力，达到增产丙烯同时生产清洁汽油的目的。小型固定流化床评价结果表明，常规FCC催化剂中添加复合共沉淀法改性分子筛制备的催化剂助剂后，液化气产率提高3.22个百分点，丙烯收率提高1.52个百分点以上，汽油研究法辛烷值提高2个单位以上。     

DC and FCC dry gas valorization on PtZrGa/MCM-41

The light olefins present in DC and FCC dry gas can be valorized into aromatics and paraffins. A new PtZrGa/MCM-41 catalyst has been synthetized and used to carry out dimerization and trimerization reactions of olefins. The catalyst was characterized by XRD and using FTIR, XPS, ⁷¹Ga and ¹H NMR spectroscopies. A blend of ethylene–propylene in presence of CS₂, hydrogen and benzene were tested in a semi-batch-type reactor. A simplified set of reaction is proposed and the operating variables were explored to study the catalytic activity and selectivity. The paper discusses the catalytic surface composition and the sensitivity of the reactions to temperature, hydrogen partial pressure and ethylene/propylene ratio. The catalyst deactivation was analyzed and the industrial implication was discussed.     

催化裂化汽油临氢异构化/芳构化改质过程的反应特性

采用工业Ni-Mo/Al₂O₃-HZSM-5催化剂在小型固定床加氢微反装置上对催化裂化（FCC）汽油临氢改质过程的反应特性进行了研究,通过考察反应温度、压力、空速和氢油体积比对改质后的FCC汽油烃类组成的影响,分析了汽油中不同烃类的转化性能。结果表明,氢油比对产物组成影响不大,高温、低压、低空速有利于增加芳烃的选择性,低温、高压、高空速则有利于增加异构烷烃的选择性;临氢改质后,FCC汽油的烯烃含量明显降低,芳烃和异构烷烃含量增加,因而产品汽油的辛烷值基本保持不变;全馏分、轻馏分和重馏分FCC汽油临氢改质实验结果表明,烯烃含量较高的轻馏分具有更高的转化活性;在FCC汽油临氢改质过程中,同碳数的端烯烃反应活性高于内烯烃,直链烯烃的反应活性高于支链烯烃。     

Study on reformulation of fluid catalytic cracking gasoline and increasing production of light olefins

The effects of reaction temperature, mass ratio of catalyst to oil, space velocity, and mass ratio of water to oil on the product distribution, the yields of light olefins (light olefins including ethylene, propylene and butylene) and the composition of the fluid catalytic cracking (FCC) gasoline upgraded over the self-made catalyst GL in a confined fluidized bed reactor were investigated. The experimental results showed that FCC gasoline was obviously reformulated under appropriate reaction conditions. The olefins (olefins with C atom number above 4) content of FCC gasoline was markedly reduced, and the aromatics content and octane number were increased. The upgraded gasoline met the new standard of gasoline, and meanwhile, higher yields of light olefins were obtained. Furthermore, higher reaction temperature, higher mass ratio of catalyst to oil, higher mass ratio of water to oil, and lower space velocity were found to be beneficial to FCC gasoline reformulation and light olefins production. __________ Translated from Chemical Reaction Engineering and Technology, 2006, 22(6): 532–538 [译自: 化学反应工程与工艺]     

不同类型氧化铝对FCC轻汽油芳构化性能影响

针对第六阶段汽油国家（国Ⅵ）标准大幅度降烯烃同时保辛烷值的生产需要，本文通过改变氧化铝基质类型，制备了系列催化裂化（FCC）轻汽油芳构化催化剂，并对催化剂酸性质和织构性质进行调变。采用X射线衍射（XRD）、N₂吸附脱附、扫描电子显微镜（SEM）、红外光谱（IR）和吡啶红外光谱（Py-IR）等手段对催化剂的物理性质进行表征，并以工业FCC轻汽油为原料对催化剂芳构化性能进行评价。实验结果表明，不同类型氧化铝的引入未对ZSM-5分子筛晶型产生影响，但可以显著调变ZSM-5分子筛的表面酸性，增加L酸中心数量。具有均一和相对较小比表面积和孔容的氧化铝材料更有利于轻汽油芳构化性能，轻汽油产品中，烯烃大幅下降（体积分数减少18.18%），异构烷烃（体积分数提高10.51%）和芳烃（体积分数提高2.75%）增幅较为明显，辛烷值损失（-5.1）较小并且可控。