Study on Olefin Decrement Reformulation and Increasing Light Olefins of FCC Gasoline by Catalytic Cracking

Abstract

Catalytic upgrading of fluid catalytic cracked (FCC) gasoline obtained from Huabei Petrochemical Company, PetroChina (Renqiu, Hebei, China), was investigated using a microreactor and gas chromatograph integrated unit in order to decrease the content of olefins in gasoline and increase the light olefins (ethylene, propylene, and butylene) content. The experimental results showed that the olefin content in upgraded gasoline can be decreased from 42.6% in raw material to nearly 10%, meeting the requirements of the new gasoline standard, whereas iso-alkane and aromatics contents were markedly increased, from 28.4 and 18.2% to 47 and 36.1%, respectively, so the octane number of gasoline should not be reduced. In addition, higher yields of light olefins were obtained after FCC gasoline was reformulated under laboratory conditions. Higher reaction temperature, longer reaction time, higher weight ratio of catalyst to oil, and higher catalyst activity were beneficial to decrease the olefin content of FCC gasoline and increase the yields of light olefins.     

催化裂化汽油的下行床催化转化

以循环下行床为反应器,催化裂化汽油为原料,在工业催化裂化(FCC)催化剂和催化裂解(DCC)催化剂作用下,研究了催化裂化汽油的催化转化过程。实验结果表明,在下行床反应器中,催化裂化汽油中的烯烃能显著降低,主要转化为低碳烯烃产品,同时得到富含芳烃的液体产品,副产干气和焦炭量很低。催化裂化汽油在FCC催化剂和DCC催化剂上表现出不同的反应机理。FCC催化剂孔道大,可以发生双分子裂化反应和单分子裂化反应,而DCC催化剂孔道小,以单分子裂化反应机理为主,同时DCC催化剂低碳烯烃选择性更高。     

工艺条件对降低催化汽油烯烃过程中汽油烯烃分布的影响

着重考察了在使用降烯烃催化剂GOR-Q和常规催化剂MLC-500时工艺条件对催化汽油烯烃分布的影响。结果表明：GOR-Q催化剂具有明显降低催化汽油各类烯烃的效果。从碳数分布看,催化汽油中的烯烃主要集中在C5～C7之间。从类型看,单烯烃是催化汽油烯烃的主要存在形式,其中又以正构烯烃和单支链烯烃为主。降低催化汽油烯烃主要是通过小分子烯烃或单烯烃、正构烯烃、单支链烯烃的降低来实现。低温、低空速、高剂油比有利于降低催化汽油中单烯烃、正构烯烃、单支链烯烃和二烯烃含量,但为了减少辛烷值的损失,在降低催化汽油烯烃时首先应采用提高剂油比的方式。     

FCC操作条件对汽油族组成及辛烷值的影响

通过对一种工业FCC催化剂在固定流化床上的评价 ,揭示了反应温度、剂油比和空速对汽油族组成及辛烷值影响的一些规律。研究发现 :随着反应温度的上升汽油中的总烷烃和异构烷烃含量下降 ,烯烃和芳烃含量上升 ;随着剂油比的增加 ,汽油中的总烷烃、异构烷烃和芳烃含量上升 ,烯烃含量下降 ;环烷烃、总烷烃、烯烃和芳烃的含量随着空速的变化出现相互交叉的现象 ;而汽油的辛烷值 (RON和MON)仅是转化率的函数 ,与达到同一转化率的操作条件无关     

降低汽油烯烃含量裂化催化剂LBO-12的研制与开发

探讨了催化裂化过程降低汽油烯烃的反应原理，研究了催化剂各组分对裂化汽油性质影响的规律性，围绕提高氢转移活性，提出制备降烯烃裂化催化剂的技术路线，并研制开发了新型LBO-12降烯烃催化剂，固定流化床反应器对中试样品的评价和工业应用结果表明，该催化剂在不损失汽油辛烷值的前提下，降低催化裂化汽油烯烃能力较强，并具有较高的水热活性稳定性和良好的抗重金属污染特性。     

相转移催化剂催化降低FCC汽油烯烃含量的研究

 将磷钨杂多酸季铵盐相转移催化剂/双氧水(Q₃[PO₄(WO₃)₄]/H₂O₂)体系应用于FCC汽油的液-液高效催化氧化降烯烃. 结果表明, 在H₂O₂用量2.5ml、剂/油质量比1:40、pH值3.33、反应温度60℃、反应时间1h的条件下, FCC汽油烯烃体积分数下降了23.56%, 而汽油辛烷值基本保持不变. 处理后的FCC汽油完全符合我国清洁汽油规定的烯烃体积分数低于35%的新标准. 对FCC汽油加入催化剂前后烯烃含量分布的分析结果表明, FCC汽油在该催化体系中烯烃含量的下降主要集中在C₅、C₆、C₇等低碳烯烃上. 另外,还对该催化氧化体系脱除FCC汽油中的硫含量进行了初步探讨.     

FCC汽油催化裂解反应的实验考察

采用微反-色谱联合的方法,考察了反应温度、反应时间及催化剂活性对哈尔滨炼油厂流化催化裂化汽油催化裂解的产品分布、低碳烯烃(乙烯、丙烯和丁烯)产率和产品汽油族组成的影响。结果表明,在反应温度590℃、剂油比170、反应时间0.24s的实验条件下,FCC汽油经催化改质后,烯烃含量大幅度下降,可由改质前的41.6%降到改质后的13.4%,满足汽油新标准的要求,而异构烷烃和芳烃含量有较大幅度增加,分别由改质前的33.3%、13.3%增到40.4%、35.7%,使汽油在降低烯烃含量的同时,辛烷值不会降低,并且还会增加低碳烯烃的产率。此外,提高反应温度、延长反应时间、提高催化剂活性均有利于降低改质汽油的烯烃含量,增产低碳烯烃。     

Conversion of n-heptane over different catalysts: Effect of catalyst-to-oil ratio and temperature

Catalytic cracking of n–heptane was investigated over various catalysts including ZSM-5, MCM-41, USY and mordenite. The influence of reaction temperature and catalyst-to-oil ratio was investigated in the case of ZSM-5 as more favorable catalyst in terms of conversion and light olefins yield. The highest n-heptane conversion of 97.3 wt.% was achieved over USY zeolite. Both conversion and olefin selectivity were increased by temperature over ZSM-5 zeolite. Increasing catalyst-to-oil ratio enhanced conversion with no significant changes in olefins selectivity. The highest olefin production was achieved over ZSM-5 zeolite in catalyst-to-oil ratios of 1.5 and 3.0 (g/g) at 550°C.     

FCC汽油提升管内降烯烃改质工艺条件的研究

利用催化裂化过程本身降低汽油烯烃含量成为近年来新型催化剂和新型工艺技术开发的主要方向，在连续小型提升管装置上，考察FCC汽油降烯烃效果与反应条件的关系。结果表明，采用普通催化裂化催化剂，当汽油烯烃降低15个百分点以上时，轻质油收率超过91％。低温、高剂油比、长反应时间和较低的再生催化剂炭含量有利于汽油烯烃的降低，汽油中C，以上烯烃降烯烃比较容易，C6烯烃有一部分发生反应，而C5烯烃基本不反应。     

降低催化裂化汽油烯烃含量的中型试验研究

在中型提升管催化裂化试验装置上详细考察了原料油性质、催化剂类型以及操作条件对催化裂化汽油烯烃含量的影响.原料油性质是决定催化裂化汽油烯烃含量高低的关键,选择氢转移活性高的稀土Y型催化剂是降低催化裂化汽油烯烃含量的有效措施.选择适宜的反应温度和油气停留时间,适当提高剂油比和催化剂活性,均可以在一定程度上降低催化裂化汽油烯烃含量.     

重质催化裂化原料加氢预处理制备清洁燃料

对一种制备清洁燃料的加氢处理—催化裂化组合工艺在实验室进行了试验。该组合工艺采用劣质蜡油加氢预处理生产催化裂化原料，然后利用石油化工科学研究院开发的降汽油烯烃催化剂进行催化裂化。研究结果表明，采用该组合工艺所生产的FCC产品中的硫含量和汽油中的烯烃含量均可以满足清洁燃料的要求。     

催化裂化操作参数对降低汽油烯烃含量的影响

针对催化裂化汽油烯烃含量较高的情况,在中型提升管催化裂化装置上,考察了原料油性质、催化剂性质、反应条件、汽油馏程等对汽油烯烃含量的影响,提出了工业生产装置降低催化裂化汽油烯烃含量的措施。研究发现,催化裂化汽油烯烃含量与氢转移指数（异丁烷／丁烯及异丁烷／异丁烯）呈线性关系,氢含量高、K值大的原料油,汽油烯烃含量较高。使用降烯烃催化剂、提高催化剂活性、提高剂油比、降低反应温度、延长反应时间、提高烃分压、提高汽油终馏点等有利于降低催化裂化汽油烯烃含量。     

催化裂化反应类型及其相互作用对产物分布和产品组成的影响

以大庆蜡油掺30％减压渣油为原料油分别用催化剂A（只含有Y型分子筛）和催化剂B（含有较多的ZSM-5分子筛）在新结构提升管装置上进行裂化反应试验；并采用烯烃模型化合物1-庚烯用催化剂A在固定流化床反应器上进行了裂化反应试验。试验结果表明，双分子裂化反应历程在催化剂A上发生机率较大，表现为较低的干气产率，较低的汽油烯烃含量；单分子裂化反应在催化剂B上发生机率较大，表现为较高的液化气和丙烯产率，产品含有较高的烯烃。1-庚烯在催化剂A上反应，具有较高的丙烯选择性，同时干气产率较低，烯烃下降幅度较大。烯烃是单分子裂化反应和双分子裂化反应理想的连结物，将单分子和双分子裂化反应特点充分发挥，从而得到较高的丙烯产率、较佳的产物分布和较低的汽油烯烃含量，为开发生产清洁汽油组分并增产丙烯的催化裂化工艺提供试验和理论依据。     

A New Downstream Process Design for a Fluid Catalytic Cracking Unit to Raise Propylene Yield and Decrease Gasoline Olefin Content

Abstract

Based on the paraffins, olefins, naphthenes, aromatics (PONA) composition of crude light gasoline, crude heavy gasoline, stabilized gasoline, and wet gas of a pilot plant fluid catalytic cracking (FCC) unit, it was found that the root cause of high gasoline olefin content and low propylene yield was low C₅ and C₆ olefin content of crude light gasoline. A new design for the main fractionater and absorber–stripper–stabilizer was presented to obtain stabilized light gasoline that contains more C₅ and C₆ olefins recracked in the secondary riser. Industrial studies on the revamped unit showed that gasoline olefin content was decreased markedly, though research octane number (RON) was preserved. In addition, propylene yield was raised to a higher level and unit energy consumption (or operating cost) was not increased.     

改性纳米HZSM-5催化剂在FCC汽油改质中的应用

 采用水热处理和负载金属氧化物对纳米HZSM－5催化剂进行组合改性。临氢条件下，在固定床反应器上考察了组合改性制备的纳米HZSM－5催化剂对FCC汽油改质的性能。300h连续运转结果表明，组合改性制备的纳米HZSM－5催化剂具有很强的降低FCC汽油中烯烃含量的能力，使改质后的FCC汽油的烯烃体积分数从49.6%降到12.8%，硫质量分数由181.2μg/g降至39.1μg/g，苯的体积分数由1.6%降至1.0%，而汽油的辛烷值没有降低。     

Aromatization Reactions of Three Gasoline Fractions

Abstract

Using a confined fluidized bed reactor and aromatization catalysts (LBO-A and LBO-16), three fluid catalytic cracking (FCC) narrow fraction gasoline (Lanlian gasoline, Shandong gasoline, and Fushun gasoline) at 420°C has been studied. The results reveal that at 420°C and a mass ratio of catalyst to oil of 5, the olefin content is remarkably reduced from about 20 to 30% (by mass) over 75% LBO-A and 25% LBO-16, and the octane number is kept at a high level after the aromatization reaction, at the same time the nine lumps model of aromatization reaction is put forward based on the corresponding mechanism. The method obtained can provide the technical instruction for the petroleum chemical plant.     

催化裂化汽油降烯烃技术的研究进展

随着环保意识的加强,国家标准对汽油中的烯烃含量限制越来越严格。本文介绍了降低催化裂化汽油烯烃的反应原理,同时从优化FCC原料及工艺条件、降烯烃催化剂、FCC技术、醚化技术等方面介绍了催化裂化汽油降烯烃技术的发展状况,指出降低FCC汽油烯烃含量需要发展一整套综合技术或措施。     

An Orthogonal Method for Aromatization Reactions of Shenghua FCC Gasoline

Abstract

Using a confined fluidized bed reactor and aromatization catalysts (LBO-A and LBO-16), the aromatization performance of Shenghua fluid catalytic cracking (FCC) gasoline has been studied in an orthogonal method. The experimental results reveal that the optimum reaction condition for the light oil yield was reaction temperature 420°C, WHSV 40 h^?1, mass ratio catalyst to oil 4 and 75% LBO-A and 25% LBO-16; the optimum reaction condition for aromatics amount in the light oil was reaction temperature 420°C, WHSV 30 h^?1, mass ratio catalyst to oil 5 and 65% LBO-A and 35% LBO-16, the olefin content is remarkably reduced from about 54.7% to 12.8% and 8.7% (by mass), respectively, at the same time the reaction mechanism of aromatization reaction is put forward based on the experimental result.     

催化裂化汽油催化改质降烯烃反应规律的试验研究

利用催化裂化催化剂在小型提升管催化裂化装置上对催化裂化汽油催化改质降烯烃过程的反应规律进行了试验研究，详细考察了反应温度、剂油比、反应时间、催化剂活性以及催化剂类型对催化裂化汽油改质降烯烃过程的影响。试验结果表明，随着反应温度、剂油比、反应时间以及催化剂活性的增加，改质汽油烯烃含量降低的幅度增加。催化裂化汽油改质后，烯烃含量大幅下降，异构烷烃和芳烃含量有较大幅度的增加，烯烃含量可以降低到汽油新标准的要求，辛烷值基本维持不变，并且汽油收率高，液体收率维持在98．5％以上，(干气 焦炭)产率损失小。     

Effect of Olefins on Formation of Sulfur Compounds in FCC Gasoline

The effect of olefins on formation of sulfur compounds in FCC gasoline was studied in a small-scale fixed fluidized bed （FFB） unit at temperatures ranging from 400℃ to 500℃, a weight hourly space velocity （WHSV） of 10 h-1, and a catalyst/oil ratio of 6. The results showed that C4--C6 olefins contained in the FCC gasoline could react with HzS to form predominantly thiophenes, alkyl-thiophenes as well as a fractional amount of thiols, while large molecular olefins such as heptene could react with hydrogen sulfide to form benzothiophenes. The amount of sulfur compounds formed at different tem- peratures over different catalysts were in proportion to the mass fractions of olefins in the feedstock, with the amount of sulfur compounds formed over REUSY catalyst exceeding those formed over the shape selective zeolite catalyst owing to the effect of catalyst performance and the impact of catalyst on the degree of olefin conversion. The amount of sulfur compounds generated and their increase reached a maximum at 450℃ and a minimum at 400℃ because of the influence of temperature on the thermodynamic and kinetic constants for formation of sulfur compound as well as on the olefin conversion degree. Based on the above-mentioned study, a reaction network and a model for prediction of sulfur compounds generated upon reaction of olefins in FCC gasoline with HES were established.