降低汽油烯烃含量FCC催化剂技术进展

从国内清洁汽油燃料需求和催化裂化过程降低汽油烯烃反应原理出发，系统论述了国内外降烯烃FCC催化剂的研究开发现状及技术发展方向，指出未来降烯烃FCC催化剂将朝着突出重油裂化、增加产品(尤其是柴油)收率、提高汽油辛烷值和多产低碳烯烃方向发展。     

甲醇作为催化裂化部分进料反应过程的可行性分析

通过对甲醇制低碳烯烃(MTO)工艺与催化裂化(FCC)工艺的相似性分析,论述了二者结合的可能性。分析了FCC提升管反应器中的温度分布、催化剂活性变化和水存在的状况,以及这些因素对MTO反应的影响。同时对不同的甲醇加入方式进行了分析,并与FCC的多产液化气和柴油工艺(在提升管反应器底部注入汽油)进行比较,提出适宜的甲醇加入位置为FCC提升管反应器底部,先于原料油进料。此过程既可将甲醇转化为低碳烯烃,又有利于重油的催化裂化反应。初步论证了甲醇作为FCC部分进料的可行性,为甲醇作为FCC部分进料以多产低碳烯烃的进一步研究指出了方向。     

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。     

两段提升管催化裂化新技术的开发：Ⅱ．提高轻质产品收率、降低催化汽油烯烃含量

两段提升管催化裂化工艺是用串联的两段提升管反应器取代原有的FCC提升管反应器,构成新的反应再生系统流程,因此克服了原FCC工艺的反应器稳定时间长的缺点。该技术的特点在于反应油气二次接触新鲜催化剂,接触时间短且分段时间反应,因此有效地提高了提升管中催化剂的平均活性和选择性,有效地抑制了热裂化及不利的二次反应,在提高转化率,汽油和轻油收率的同时,大幅度降低了催化汽油中烯烃的含量,增加了异构烷烃和芳烃含量,提高了汽油的辛烷值。     

FCC 汽油烯烃双分子裂化反应及其与双分子氢转移反应之比的研究

以催化裂化汽油为原料在不同类型的催化剂上进行了催化转化试验，探讨了不同类型的氢转移反应在烯烃转化中的作用。结果表明，汽油烯烃在不同类型的催化剂上发生裂化反应强弱及其与氢转移反应之比大小是不同的；再生催化剂有利于裂化反应，有利于提高裂化反应与氢转移反应之比；较高的反应温度和较高的重时空速有利于裂化反应，有利于提高裂化反应与氢转移反应之比。     

满足国Ⅵ标准的FCC汽油改质技术研究

介绍了3种基于汽油分子组成的催化裂化(FCC)汽油改质技术,以烯烃定向转化为基础,在降低FCC汽油烯烃含量的同时,最大限度减少辛烷值损失,使产品满足国Ⅵ汽油质量标准。其中,骨架异构技术以全馏分FCC汽油为原料,强化催化剂的异构化性能。中试结果表明,加氢条件下,在硫和烯烃含量达标的同时,RON损失仅0.7单位;异构-醚化组合技术以C_5烯烃为原料,经异构化过程将其中的直链烯烃转化为叔碳烯烃,再与甲醇醚化生成甲基叔戊基醚(TAME),相比于正构烯烃,RON可提高21.1单位;芳构化技术将正构烯烃定向转化为辛烷值很高的芳烃产品,同时实现降低烯烃含量和提高辛烷值的目标。     

催化裂化汽油裂解制备低碳烯烃

在小型提升管催化裂化实验装置上研究了催化裂化(FCC)汽油催化裂解生产低碳烯烃的反应规律。实验结果表明,催化剂类型、反应温度、停留时间及水蒸气用量对乙烯、丙烯的产率均有显著的影响。高温、大剂油比、长停留时间及提高水蒸气用量都可促进汽油的裂解,增加低碳烯烃的产率。在实验室条件下,以ZC-7300为催化剂,多产低碳烯烃的最佳条件:反应温度580℃,停留时间1.6s左右,剂油质量比为11,水蒸气与汽油的质量比为0.20。对不同催化剂进行了对比实验得知,自制催化剂A的催化效果最好,汽油转化率达到40%以上,乙烯+丙烯的产率达到20%以上,焦炭和干气(不含乙烯)的产率不大于5%。     

大庆蜡油在酸性催化剂上反应机理的研究

以大庆蜡油为原料，采用两种不同类型的催化剂，在流化床反应器实验装鬣上进行催化裂化反应。结果表明，大庆蜡油在酸性催化剂上反应所产生的干气组成与高烯烃催化裂化汽油相同，干气的产生主要是单分子裂化反应所造成的。从干气产率、组成以及液化气组成可以看出，大庆蜡油在不同类型的催化剂上明显地表现出裂化反应类型的差异。     

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。     

Comparison of Downer and Riser Based Fluid Catalytic Cracking Process at High Severity Condition: A Pilot Plant Study

Integration of refining and petrochemicals offers economic benefits to both the industries. Converting low value refinery products to high value petrochemicals require novel processes and extra investment. Though FCC is not a new process to the refining industry, it still has a potential for modification to enhance light olefins demanded by reformulated gasoline and the petrochemical industry. In this article a novel, High Severity FCC process based on the downer reactor is presented. Supported by the pilot plant study and comparison with riser, it is shown that the downer FCC reduces backmixing, which is the main cause of gasoline overcracking. Reduction of backmixing reduces coke and dry gas formation, resulting in increased yield of gasoline. Despite the operation at higher temperature, there is reduction in the thermal cracking. Though the light olefins yield is lower in case of downer, the total yield of useful products (gasoline + light olefins) is higher in downer as compared to the same from a riser. The increased yield of gasoline from downer can be converted to light olefins by using ZSM-5 based additives.     

Comparison of Downer and Riser Based Fluid Catalytic Cracking Process at High Severity Condition: A Pilot Plant Study

Abstract

Integration of refining and petrochemicals offers economic benefits to both the industries. Converting low value refinery products to high value petrochemicals require novel processes and extra investment. Though FCC is not a new process to the refining industry, it still has a potential for modification to enhance light olefins demanded by reformulated gasoline and the petrochemical industry. In this article a novel, High Severity FCC process based on the downer reactor is presented. Supported by the pilot plant study and comparison with riser, it is shown that the downer FCC reduces backmixing, which is the main cause of gasoline overcracking. Reduction of backmixing reduces coke and dry gas formation, resulting in increased yield of gasoline. Despite the operation at higher temperature, there is reduction in the thermal cracking. Though the light olefins yield is lower in case of downer, the total yield of useful products (gasoline + light olefins) is higher in downer as compared to the same from a riser. The increased yield of gasoline from downer can be converted to light olefins by using ZSM-5 based additives.     

EFFECT OF ZSM-5 ADDITION ON PRODUCT DISTRIBUTION IN A HIGH SEVERITY FCC MODE

The high-severity fluid catalytic cracking (HS-FCC) process is a novel FCC process that enhances light olefins yield under high severity reaction conditions. The process has been investigated by using a small-scale FCC pilot plant (0.1 BPD) with a down-flow reactor. High severity reaction conditions are preferable for enhancing the production of light olefins by catalytic cracking of heavy oils. As another option for the light olefin production, adoption of ZSM-5 additive in conventional FCC units is well known. This presentation describes the effect of ZSM-5 additive on the catalytic cracking of vacuum gas oil under high severity reaction conditions, particularly focusing on the synergistic effect with the base catalyst. Three kinds of FCC catalysts with different activity were used as base catalysts. Although the employment of a ZSM-5 additive resulted in significant increase in the light olefins yield at the expense of gasoline in each catalyst system tested, the effectiveness was varied depending on the nature of the base catalysts. By choosing a suitable base cracking catalyst, more than 20 wt% of propylene yield was obtained at a one-pass conversion of fresh feed.     

EFFECT OF ZSM-5 ADDITION ON PRODUCT DISTRIBUTION IN A HIGH SEVERITY FCC MODE

The high-severity fluid catalytic cracking (HS-FCC) process is a novel FCC process that enhances light olefins yield under high severity reaction conditions. The process has been investigated by using a small-scale FCC pilot plant (0.1 BPD) with a down-flow reactor. High severity reaction conditions are preferable for enhancing the production of light olefins by catalytic cracking of heavy oils. As another option for the light olefin production, adoption of ZSM-5 additive in conventional FCC units is well known. This presentation describes the effect of ZSM-5 additive on the catalytic cracking of vacuum gas oil under high severity reaction conditions, particularly focusing on the synergistic effect with the base catalyst. Three kinds of FCC catalysts with different activity were used as base catalysts. Although the employment of a ZSM-5 additive resulted in significant increase in the light olefins yield at the expense of gasoline in each catalyst system tested, the effectiveness was varied depending on the nature of the base catalysts. By choosing a suitable base cracking catalyst, more than 20 wt% of propylene yield was obtained at a one-pass conversion of fresh feed.     

Investigation of the Operating Conditions on Decreasing FCC Gasoline Olefin Content by GOR-Q Catalyst

Abstract

Based on a fixed-fluid-bed reactor and a GOR-Q catalyst, the influence of process parameters on decreasing gasoline olefin content was studied. The results show that the catalyst had an obvious effect on the decreasing gasoline olefins. A higher catalyst-to-oil ratio, lower weighted hourly space velocity, and lower reactor temperature give rise to lower gasoline olefin content. The reduction of fluid catalytic cracking (FCC) gasoline olefin content is achieved by decreasing olefins of low carbon number. Reaction temperature under 520°C and catalyst-to-oil ratio = 7.0 for a GOR-Q catalyst are advantageous for decreasing olefin content of FCC gasoline.     

纳米HZSM-5沸石催化剂上催化裂化轻汽油的芳构化

利用小型固定床加压反应器在纳米 HZSM-5沸石催化剂上进行了流化催化裂化(FCC)轻汽油(馏出温度小于等于85℃的馏分)的芳构化反应。实验结果表明,在反应温度为360～400℃、反应压力为1.0～3.0 MPa、重时空速为1.0～4.0 h~(-1)、V(H_2)∶V(原料)为260、反应时间48 h 的条件下,FCC 轻汽油中的 C_5~+烯烃转化率为39.11%～97.92%,产物中芳烃净增量为2.59%～19.05%,说明 FCC 轻汽油可在纳米 HZSM-5沸石催化剂上有效进行芳构化反应。汽油收率低和催化剂失活快是 FCC轻汽油在纳米 HZSM-5沸石催化剂上进行芳构化反应需要解决的两个主要问题。对纳米 HZSM-5沸石催化剂进行必要的改性处理及脱除原料中的二烯烃杂质呵以改进 FCC 轻汽油芳构化催化剂的性能。     

FCC汽油重馏分的单分子和双分子裂化反应特征产物的生成途径Ⅰ. 在不同类型催化剂上的裂化机理比率（CMR）

 以FCC汽油重馏分为原料油，采用不同类型的酸性催化剂，在小型固定流化床装置上进行催化裂化反应，反应温度为400～520℃。结果表明，不同类型的酸性催化剂，其裂化机理比率（CMR）明显不同，并与强B酸量和弱B酸量有关。酸性催化剂强B酸量越高，对单分子反应越有利; 弱B酸量越高, 对双分子反应越有利，单分子反应和双分子反应之间存在竞争。