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.

Research on Catalytic Cracking Performance Improvement of Waste FCC Catalyst by Magnesium Modification

In this study,the deactivation mechanism caused by high accessibility of strong acid sites for the waste FCC catalyst was proposed and verified for the first time.Based on the proposed deactivation mechanism,magnesium modification through magnesium chloride impregnation was employed for the regeneration of waste FCC catalyst.The regenerated waste FCC catalyst was characterized,with its heavy oil catalytic cracking performance tested.The characterization results indicated that,in comparison with the unmodified waste FCC catalyst,the acid sites strength of the regenerated waste FCC catalyst was weakened,with no prominent alterations of the total acid sites quantity and textural properties.The heavy oil catalytic cracking results suggested that the catalytic cracking performance of the regenerated waste FCC catalyst was greatly improved due to the suitable surface acidity of the sample.In contrast with the unmodified waste FCC catalyst,the gasoline yield over the regenerated waste FCC catalyst significantly increased by 3.04 percentage points,meanwhile the yield of dry gas,LPG,coke and bottoms obviously decreased by 0.36,0.81,1.28 and 0.87 percentage points,respectively,making the regenerated waste FCC catalyst serve as a partial substitute for the fresh FCC catalyst.Finally,the acid property change mechanism was discussed.

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.

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.

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℃.

FCC废催化剂磁分离技术的工业应用

利用电磁分离设备和永磁分离设备,对4种典型的FCC废催化剂进行分离,考察废催化剂中金属含量对磁分离效果的影响,同时对比分析两种类型磁分离设备的使用效果。结果表明,磁分离对满足特定条件的FCC废催化剂中低金属颗粒的回收有明显效果。在工业应用中,应有选择性地采用磁分离设备对FCC废催化剂进行回收。

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。

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。

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。

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。

FCC汽油二次裂化增产丙烯过程中主要影响因素的研究

利用提升管中试实验装置,研究了催化汽油二次裂化制丙烯过程中热裂化、氢转移反应的特点和影响因素,给出了不同反应条件对丙烯选择性的影响,考察了丙烯选择性最大点处热裂化反应、氢转移反应的变化。研究结果表明,采用适当的反应温度和剂油比以及缩短反应时间能有效抑制热裂化反应和氢转移反应的发生,提高丙烯的选择性。

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。

FCC汽油催化转化动力学模型

以催化裂化反应机理为基础,将FCC汽油原料及产品按馏程和化学组成进行集总划分。考虑裂化、氢转移、芳构化和缩合等反应,对反应网络进行合理简化,提出了一种接近分子水平的动力学模型。通过参数估算求取14个动力学速率常数、反应活化能和指前因子,建立了汽油催化转化反应的十集总动力学模型。研究结果表明,采用该模型能预测不同反应条件下汽油转化反应产率分布和产品中汽油的烃类组成。

FCC汽油重馏分的催化裂化和热裂化产物组成的研究

以FCC汽油重馏分为原料，分别在惰性石英砂及酸性催化剂上，反应温度为300 -700℃，在小型固定流化床上进行热裂化和催化裂化实验。结果表明，FCC汽油重馏分的热裂化起始反应温度为525℃左右。在催化裂化实验中，当反应温度为300-500℃时，FCC汽油重馏分催化裂化所得的干气100％由单分子裂化反应所产生；525℃时93％的干气由单分子裂化反应产生；550℃时63％的干气由单分子裂化反应产生；反应温度高于600℃时，干气几乎100％由热裂化反应所产生。单分子裂化反应所产生的干气组成中，按体积分数大小的顺序依次为C2H4、CH4、H2和C2H6。而热裂化反应所产生的干气组成中，CH4体积分数最高，约占50％，其次为H2，然后依次为C2H4、C2H6。当反应温度为300～600℃时，FCC汽油重馏分催化裂化所得的液化气80％～100％由催化裂化反应所产生，其主要组成为C3H4、iC4H10和C3H8，而热裂化液化气的主要组分为C3H6、iC4H8和C3H8。

碱性氮化物对CGO FCC反应性能的影响及其结构分析

利用甲酸抽提的方式,富集了辽河焦化蜡油中的碱性氮化物,对抽提前后油样的FCC反应性能在小型固定流化床实验装置上进行了考察,并对富集所得到的碱性氮化物的结构利用傅里叶离子回旋共振质谱进行了分析。试验结果表明,甲酸对碱性氮化物有较好的富集效果,碱性氮化物的抽提效率达到了95%以上;FCC反应性能评价表明,去除碱性氮化物以后,萃余油的FCC反应性能得到改善,汽油、柴油收率增加,焦炭产率降低,转化率、轻质油收率及液收率增加;傅里叶离子回旋共振质谱结果表明:辽河CGO中的碱性氮化物主要为喹啉、吖啶类化合物。

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。

FCC汽油选择性HDS催化剂Co-Mo/镁铝尖晶石-Al2O3的研制

采用镁铝尖晶石(MgAl2O4)对γ-Al2O3进行了改性,并以其为载体,以Co-Mo为活性组元,采用等体积浸渍法制备了一系列MgAl2O4含量不同的Co-Mo/MgAl2O4-Al2O3催化剂。以FCC汽油为原料,在高压微反装置上对Co-Mo/MgAl2O4-Al2O3催化剂的加氢脱硫(HDS)活性进行了评价,计算了催化剂的HDS选择性因子。采用低温N2吸附-脱附、XRD、NH3-TPD、Py-IR及TPR手段对镁铝尖晶石改性后载体和相应催化剂进行了表征。结果表明,Co-Mo/MgAl2O4-Al2O3催化剂具有较高的HDS活性和较大的HDS选择性因子。镁铝尖晶石的加入减弱了载体的酸性,减弱了金属与载体的相互作用,提高了催化活性,降低了反应温度,从而使催化剂的HDS选择性因子提高。在MgAl2O4-Al2O3载体中镁铝尖晶石质量分数为50%时,其所制备的Co-Mo/MgAl2O4-Al2O3的HDS选择性因子达到最大值。

FCC汽油催化裂解生产低碳烯烃的动力学模型研究

针对催化裂化汽油催化裂解生产低碳烯烃的反应体系,建立了六集总动力学模型,推导出模型的解析解,利用小型提升管催化裂化试验装置的试验数据,采用最小二乘法求出了各集总之间的反应速率常数,并对所建立的模型进行了初步的检验,结果表明计算值与试验值吻合良好,模型具有较好的预测能力。对乙烯、丙烯的产率及选择性的计算表明,随停留时间的延长,产率有所增加,但选择性基本不变。