Enhancing hydrothermal stability of nano-sized HZSM-5 zeolite by phosphorus modification for olefin catalytic cracking of full-range FCC gasoline

In this study, phosphorus modification by trimethyl phosphate impregnation was employed to enhance the hydrothermal stability of nano‐sized HZSM‐5 zeolites. A parallel modification was studied by ammonium dihydrogen phosphate impregnation. The modified zeolites were subjected to steam treatment at 800 °C for 4 h (100% steam) and employed as catalysts for olefin catalyticcracking (OCC) of full‐range fluid catalytic cracking (FCC) gasoline. X‐ray diffraction, N2 physicaladsorption and NH3 temperature‐programmed desorption analysis indicated that, although significantimprovements to the hydrothermal stability of nano‐sized HZSM‐5 zeolites can be observedwhen adopting both phosphorus modification strategies, impregnation with trimethyl phosphatedisplays further enhancement of the hydrothermal stability. This is because higher structural crystallinityis retained, larger specific surface areas/micropore volumes form, and there are greaternumbers of surface acid sites. Reaction experiments conducted using a fixed‐bed micro‐reactor(catalyst/oil ratio = 4, time on stream = 4 s) showed OCC of full‐range FCC gasoline-under a fluidized‐bed reaction mode configuration-to be a viable solution for the olefin problem of FCC gasoline.This reaction significantly decreased the olefin content in the full‐range FCC gasoline feed, andspecifically heavy‐end olefins, by converting the olefins into value‐added C2–C4 olefins and aromatics.At the same time, sulfide content of the gasoline decreased via a non‐hydrodesulfurization process.Nano‐sized HZSM‐5 zeolites modified with trimethyl phosphate exhibited enhanced catalytic performance for OCC of full‐range FCC gasoline.

Fluid Catalytic Cracking Technology for Maximum Gasoline Production

Increasing gasoline production in FCC unit can improve the utilization efficiency of petroleum resources and gain economic benefit.This paper discusses the technical principles for increasing FCC gasoline yield from the aspects of feedstock properties,operating conditions,LCO(light cycle oil)recycling,catalyst selection and reactor type,and illustrates the industrial application examples for maximizing gasoline production.The technical measures,such as optimizing the feedstock,properly increasing the catalyst activity and reaction temperature,recycling LCO or hydrotreated LCO,applying high gasoline yield catalyst,and adopting the two-zone riser reactor,are proposed to enhance the gasoline yield.

Study of Carbon Nanotube Supported Co-Mo Selective Hydrodesulphurization Catalysts for Fluid Catalytic Cracking Gasoline

In this paper, carbon nanotube supported Co-Mo catalysts for selective hydrodesulphurization （HDS） of fluid catalytic cracking （FCC） gasoline were studied, using di-isobutylene, cyclohexene, 1-octene and thiophene as model compounds to simulate FCC gasoline. The results show that the Co-Mo/CNT has very high HDS activity and HDS/hydrogenation selectivity comparing with the Co-Mo/γ-Al2O3 and Co-Mo/AC catalyst systems. The saturation ratio of cyclohexene was lower than 50%, and the saturation ratio of 1,3-di-isobutylene lower than 60% for the Co-Mo/CNT catalysts. Co/Mo atomic ratio was found to be one of the most important key factors in influencing the hydrogenation selectivity and HDS activity, and the most suitable Co/Mo atomic ratio was 0.4. Co/CNT and Mo/CNT mono-metallic catalysts showed lower HDS activity and selectivity than the Co-Mo/CNT bi-metallic catalysts.

Highly Selective Conversion of Olefin Components in FCC Gasoline to Propylene in Monolithic Catalytic Reactors

The demand for propylene has been growing recently. The concentration of olefins in the gasoline is strictly limited by the related environmental regulations. The olefins contained in the gasoline used as the feed could be cracked into light olefins to slash the olefin concentration in the gasoline to yield more propylene at the same time. The monolithic catalyst washcoated on the modified ZSM-5 zeolite was used in the experiments. The effect of the temperature, the Si/Al ratio in ZSM-5 and the addition of the rare earth elements on the selectivities and the yields of the light olefins were studied. The high yields of propylene and butene could be obtained under the experimental conditions of a higher temperature and Si/Al ratio with the addition of rare earth elements.

Industrial Application and Fundamental Research Progress on Fluid Catalytic Cracking Technology of Downer Reactors

Fluid catalytic cracking(FCC)technologies of downer reactors,which have reached the demonstration or commercial scale,are systematically discussed,i.e.,millisecond catalytic cracking,fluidization lab of Tsinghua University,and high-severity FCC.Moreover,aiming to promote industrial application,the fundamental studies are comprehensively described,particularly focusing on high-density downer reactors,clusters,and up-scaling.Furthermore,from the perspective of industrial application,some research directions toward further developments are suggested.

Catalytic Cracking of Polyolefins in the Molten Phase——Basic Study for the Process Development of Waste Plastics Liquefaction

The cracking of polyolefins, especially polyethylene in the molten state was effectively catalyzed by the powdery spent FCC （Fluid Catalytic Cracking） catalyst which was dispersed in it. The activation energy of the catalytic cracking of polyethylene was about 74 kJ/mol. The cracked product was naphtha and middle distillate as the major product and gaseous hydrocarbon （C1-C4） as the minor product while little heavy oil was produced. The chemical compositions of the product were： aromatic hydrocarbons, isoparaffins and branched olefins, whereas that of the non-catalyzed products were： n-olefins and n-paraffins with minor amount of dienes with increasing the process time. Additionally, the product pattern shifted from naphtha rich product to kerosene and gas-oil rich product. However, any catalytic product showed low fluid point （〈 -10 ℃）, while that of the non-catalyzed product was as high as 40 ℃. Catalyst could process, more than 100 times by weight of polyethylene with fairly small amount （- 30 wt%） of coke deposition. Spent catalyst gave higher hydrocarbons while fresh catalyst gave gaseous product as the major product. Other polyolefins such as polypropylene and polystyrene were tested on same catalyst to show that their reactivity is higher than that of polyethylene and gave the aliphatic products, alkyl benzenes and C6-C9 iso-paraffins as the major product. Product pattern of the cracked product suggested that the reaction proceeded via the primary reactions making paraffins and olefins which were followed by the isomerization, secondary cracking, aromatization and hydrogen transfer which based on the carbenium ion mechanism.

Development and Commercial Application of RFCC Catalyst for Reducing Sulfur Content in Gasoline

The sulfur-reducing functional component the Lewis acid-base pair compound and associated active zeolite component were developed to prepare the RFCC catalyst DOS for reducing sulfur content in gasoline. The results of catalyst evaluation have revealed that the Lewis acid-base pair compound developed hereby could enhance the conversion of macromolecular sulfur compounds by the catalyst to promote the proceeding of desulfurization reactions, and the synergetic action of the selected zeolite and the Lewis acid-base pair compound could definitely reduce the olefins and sulfur contents in gasoline. The heavy oil conversion capability of the catalyst DOS thus developed was higher coupled with an enhanced resistance to heavy metals contamination to reduce the sulfur content in gasoline by over 20%. The commercial application of this catalyst at the SINOPEC Jiujiang Branch Company has revealed that compared to the GRV-C catalyst the oil slurry yield obtained by the catalyst DOS was reduced along with an improved coke selectivity, an increased total liquid yield, and a decreased olefin content in gasoline. The ratio of sulfur in gasoline/sulfur in feed oil could be reduced by 20.3 m%.

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

The effects of reaction temperature,mass ratio of catalystto oil,space velocity,andmass 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 con-ditions.The olefins(olefins with C atom number above 4)content of FCC gasoline was markedly reduced,and the aromaticscontent andoctanenumber 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.

Effects of the properties of FCCS on the removing of catalyst particles from FCCS under a DC electrostatic field

Catalytic cracking is the main method to lighten heavy crude oil,this process can produce high quality oil products such as gasoline and diesel,but also produces a large amount of fluid catalytic cracking slurry(FCCS).The catalyst particles in FCCS seriously restrict the secondary processing of FCCS and need to be removed,and the properties of Fccs is an important factor that affects the removal efficiency of the catalyst particles.Based on the"effective contact point"model proposed by the research group,this study further proposed the"electrostatic separation efficiency calculation"model.In this model,since Fccs has a uniform distribution of catalyst particles,the ratio of the number of catalyst particles can be expressed as the ratio of area to achieve the calculation of separation efficiency.Then the catalyst removal efficiency under different viscosity was analyzed,thus verifying the feasibility of this model.The effects of temperature and mass ratio of four components on the viscosity of FccS were investigated respectively,then the effects of temperature and four components'mass ratio on the electrostatic sep-aration can be directly converted into the effect of viscosity on the electrostatic separation efficiency.All the results show the electrostatic separation efficiency decreases with increasing viscosity,and the best separationtemperatureis120℃.

CFD SIMULATION OF FLUID CATALYTIC CRACKING IN DOWNER REACTORS

A mathematical model has been developed for the simulation of gas-particle flow and fluid catalytic cracking in downer reactors. The model takes into account both cracking reaction and flow behavior through a four-lump reaction kinetics coupled with two-phase turbulent flow. The prediction results show that the relatively large change of gas velocity affects directly the axial distribution of solids velocity and void fraction, which significantly interact with the chemical reaction. Furthermore, model simulations are carried out to determine the effects of such parameters on product yields, as bed diameter, reaction temperature and the ratio of catalyst to oil, which are helpful for optimizing the yields of desired products. The model equations are coded and solved on CFX4.4.

FCC汽油中硫分布和催化脱硫研究

对胜利石油化工总厂的FCC汽油中的硫含量、硫分布及硫化物的种类进行了分析。该汽油中的硫含量高 ,且 90 %的硫都集中在占 65 %的 10 0℃以上的汽油馏分中。采用配有PFPD检测器的色谱分析了 10 0℃以上的汽油馏分中硫化物的种类 ,结果表明 ,近 90 %的硫化物都是噻吩类化合物。对不同的汽油脱硫方法进行了分析 ,提出了汽油催化裂化脱硫全新方法 ,并开发出了具有显著脱硫效果的脱硫催化剂。

FCC汽油非临氢脱硫技术进展

综述了国内外开发和应用的FCC汽油非临氢脱硫技术,该技术主要有生物脱硫、催化裂化脱硫、吸附脱硫、溶剂抽提脱硫、烷基化脱硫、氧化脱硫和膜分离脱硫等;评述了催化裂化脱硫、吸附脱硫和氧化脱硫等技术的特点和研究应用前景。

ZRP沸石对FCC汽油催化裂解产丙烯的影响

研究了在550℃、常压、加入水蒸气条件下,FCC汽油在ZRP沸石上的催化裂解反应和ZRP沸石硅/铝比(n(SiO2)/n(Al2O3))变化及稀土改性ZRP对反应的影响。实验结果和反应前后反应物与产物分布的计算结果表明,FCC汽油中烯烃进行裂化反应生成丙烯。提高烯烃的选择性转化、促进裂化反应并提高丙烯产物的选择性,有利于提高丙烯产率。提高ZRP沸石的n(SiO2)/n(Al2O3)能够增加其强酸量,使烯烃的转化率和低碳烯烃的选择性有所提高,但丁烯选择性高于丙烯的选择性。采用稀土改性也可使ZRP沸石增加强酸量,提高烯烃的转化率和丙烯的选择性,使74.32%的烯烃被转化,裂解汽油烯烃质量分数为18.20%,丙烯选择性达到45.91%。

FCC轻汽油催化裂化生产丙烯反应规律的研究

在提升管实验装置和脉冲色谱装置上,采用ZSM-5催化剂,考察了不同条件下FCC轻汽油和2M-1-C=5的裂化。结果表明,催化裂化过程添加ZSM-5催化剂可提高汽油中C=5、C=6的质量分数。轻汽油裂化生产丙烯的性能优于重汽油和全馏分汽油,在相对低的温度下瞬时反应能得到较高的丙烯收率。在脉冲色谱装置上,反应温度和载气流量对轻汽油和2M-1-C=5裂化生产丙烯的影响一致,即反应温度升高,载气流量降低,丙烯收率增加。提高反应温度,延长停留时间可以提高丙烯对丁烯的比例。轻汽油在ZSM-5催化剂上反应,催化剂结焦失活速度开始较快,后来减缓。ZSM-5催化剂结焦失活对丙烯生成的抑制作用大于对丁烯的抑制作用,ZSM5-的强酸中心多则更有利于生成丙烯。

生产低硫汽油新型FCC催化剂研究进展

介绍了国内外低硫汽油生产技术 ,重点讨论了催化裂化过程硫转化机理及国内外脱硫FCC催化剂的研究开发现状。结果表明 :在B酸或L酸的作用下 ,通过氢转移使FCC汽油中的噻吩硫及其衍生物分解生成H2 S气体 ,以达到降低FCC汽油硫含量的目的 ,这在反应机理上是可行的 ,因此 ,开发新型FCC催化剂 ,对于实现催化裂化过程直接脱硫 ,生产低硫汽油具有实际意义。

FRS全馏分FCC汽油加氢脱硫技术开发及工业应用

抚顺石油化工研究院(FRIPP)开发的FRS全馏分FCC汽油加氢脱硫技术具有大幅度降低催化汽油硫含量和烯烃含量而辛烷值损失较低的特点。在中国石油化工股份有限公司九江分公司0.4Mt/a装置上的工业应用结果表明,FRS技术能够为我国炼油厂生产清洁汽油提供灵活、经济的技术解决方案。

CO吸附原位红外光谱结合分子模拟计算研究FCC汽油加氢脱硫催化剂的选择性

以脱硫选择性不同的2组催化裂化汽油加氢脱硫催化剂为研究对象,采用CO吸附原位红外光谱表征了2组催化剂的活性相特征,并通过分子模拟计算方法比较了助剂Co加入前后噻吩和1-己烯在催化剂表面的电荷分布、吸附能及其加氢反应的活化能等,探讨了助剂Co的加入对选择性加氢脱硫催化剂脱硫选择性的作用机理.结果表明,加氢脱硫催化剂CoMoS活性相的增加有利于提高催化剂的加氢脱硫/加氢降烯烃(HDS/HYD)选择性.与1-己烯加氢位相比,Co的加入显著提高了噻吩分子加氢位的缺电子性,噻吩在催化剂表面的吸附度增强,显著降低噻吩加氢反应的能垒,从而使噻吩加氢反应更易进行.这也表明CoMoS为高HDS活性、高HDS/HYD选择性的活性相.

催化剂上沉积钒氧化数对降低FCC汽油中硫含量的影响

过滤金属化合物与硫化物相互作用的分子模拟研究结果表明,低氧化数钒的氧化物有利于促进硫化物的转化。然而,工业运转中催化剂在进入反应器前已经历氧化再生,沉积于其上的钒处于高氧化数状态,为此提出了强化降低催化剂上沉积钒氧化数的"择效活化"方法。电子顺磁共振(ESR)结果表明,通过择效活化处理,催化剂上沉积钒的氧化数下降。重油微反评价结果表明,高钒活化剂进一步表现出明显优于高钒再生剂的降硫作用;高钒人工污染再生剂具有强于未污染剂的降硫作用,并且经择效活化后,高钒污染活化剂进一步表现出明显优于高钒污染再生剂的降硫作用,评价实验证实了分子模拟计算的结果。

FCC汽油加氢脱硫/降烯烃新技术的开发

介绍了中国石化抚顺石油化工研究院(FRIPP)开发的OCT M、FRS和OTA催化裂化(FCC)汽油加氢脱硫/降烯烃技术。这些技术针对我国不同硫和烯烃含量的FCC汽油分别进行加氢处理,在大幅度降低硫含量和烯烃含量的同时,辛烷值损失较少,为炼油企业生产清洁汽油提供了灵活、经济的技术解决方案。

CGO关键组分结构分析及其对FCC反应性能的影响

以大港焦化蜡油(CGO)400～425℃窄馏分为研究对象,采用盐酸+糠醛分级抽提的方法富集其中的碱性氮化物及稠环芳烃,采用GC-MS对抽出物进行结构分析,并比较了抽提前后油样的FCC反应性能。结果表明,盐酸抽出相中的碱性氮化物主要是氮杂菲系和氮杂芘系,其中以苯并喹啉系及二苯并喹啉系含量最多;这类化合物与催化剂活性中心结合,使催化剂活性下降。糠醛再抽提抽出相中的稠环芳烃包括荧蒽、苯基萘、菲蒽系、芘系及苯并芘系,其中3～4环的稠环芳烃所占比例最大;这类化合物在催化剂表面缩合生焦,降低了CGO的FCC反应性能。盐酸及糠醛抽余油的FCC反应性能均得到了改善,但糠醛抽余油的改善程度不及盐酸抽余油;碱性氮化物对CGO的FCC反应性能的影响比稠环芳烃大。