直馏柴油催化裂化加工技术探索

采用小型固定流化床实验装置,探索研究了直馏柴油催化裂化加工技术路线的可行性。结果表明：催化裂化是将直馏柴油转化为高附加值产物的切实可行的工艺技术;采用催化裂化技术路线时,直馏柴油直接催化裂化反应具有较高的汽油和丙烯收率,分别可达48%和8%左右;采用催化裂解技术路线时,直馏柴油直接催化裂解反应具有较高的低碳烯烃和BTX（苯、甲苯和二甲苯）收率,在反应温度为620℃时乙烯、丙烯和BTX总收率可达39%以上,并可副产22％以上的高辛烷值汽油,其 RON在99以上;重油原料掺炼直馏柴油时,直馏柴油掺入比例较高时催化裂化反应性能较好,但会导致汽油产物中芳烃含量增加。     

The Addition of ZSM-5 to a Fluid Catalytic Cracking Catalyst for Increasing Olefins in Fluid Catalytic Cracking Light Gas

Abstract

The second largest source of propylene supplied for petrochemical application is from fluid catalytic cracking (FCC) units. The primary function of the FCC unit has typically been to produce gasoline. However, refiners have been taking advantage of opportunity to produce and recover more propylene from their FCC unit by increasing reaction severity via riser temperature, adding shape selective catalyst, and installing a propylene recovery unit (PRU). At a conventional FCC process propylene exists in the off gas of FCC and it is about 6 wt% of off gas by changing the FCC process parameter quantity of propylene in off gas can be more than 20 wt% by using ZSM-5 additives and increasing temperature The effects of operating parameters, such as reaction temperature, and ZSM-5 as FCC catalyst additive, on the distribution of the product and the yield of propylene were investigated on a bench-scale fluidized bed reactor. It is the aim of this work to perform an overall analysis of the yields and selectivity of hydrocarbons obtained in the vacuum gas-oil conversion over FCC and ZSM-5 catalysts. The effectiveness of ZSM-5 additive in the FCC process was investigated by doing experimental work in a bench-scale setup. The experiment data of off gas analysis showed that vacuum gas oil cracking at high reaction temperatures of 450–550°C increases the yield of propylene. Similar behavior is observed with the addition of 10–25 wt% ZSM-5 additive. The combination of the two effects (high temperature and ZSM-5 addition) makes the FCC unit an excellent source of light olefins for downstream petrochemical units. Higher FCC reactor temperatures (600–650°C) would not have positive effects for increasing propylene yield.     

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。     

A Kinetics Lumped Model for VGO Catalytic Cracking in a Fluidized Bed Reactor

Abstract

Fluid catalytic cracking (FCC) is a process used to converted heavy petroleum products to light products such as gasoline, light fuel oil, and petroleum gas. In the fluid catalytic cracking reactor heavy gas oil is cracked into more valuable lighter hydrocarbon products. The reactor input is a mixture of hydrocarbons that makes the reaction kinetics very complicated due to the involved reactions. In this article, a four-lump model is proposed to describe the kinetics of vacuum gas–oil (VGO) cracking in the FCC process. This model is different from other models mainly in that the deposition rate of coke on catalyst can be predicted from gas–oil conversion and isolated from the C1-C4 gas yield. By this lumped model for the kinetic of cracking VGO we can also conclude that the C1-C4 gas yield increases with increasing reactor temperature, whereas the production of gasoline and coke decreases. We can also conclude that with decreasing space velocity the product yield will increase.     

加入甲醇对直馏汽油裂化反应的影响

采用小型固定流化床装置研究甲醇作为催化裂化部分进料的反应过程,考察了加入甲醇对直馏汽油裂化反应的影响,比较了不同进料方式的反应过程,分析加入甲醇后的催化裂化反应规律。结果表明,甲醇与直馏汽油同时进料相对于单独的直馏汽油裂化,气体产率增加,并可维持低碳烯烃的选择性;产物汽油的正构烷烃、异构烷烃、环烷烃含量降低,烯烃含量略有增加,芳烃含量增加。对甲醇作为催化裂化部分进料过程的反应机理进行了初步探讨。     

MIP技术在提高液体产品收率上的先进性分析

对具有代表性的工业MIP装置与FDFCC装置、FCC装置和TSRFCC装置的液体产品收率进行对比分析。结果表明：无论是以加氢重油还是以加氢蜡油或者是常压渣油为原料,采用MIP工艺时,汽油与液化气产率均较高,而干气与油浆产率较低,液体产品收率较高;与其它同类技术相比,其液体产品收率最少提高2百分点;且MIP技术的汽柴比高,所生产汽油硫含量低、烯烃含量较低而辛烷值与其它技术相当或较高。这主要是由于MIP技术采用具有独特的双反应区的提升管反应器,并在不同反应区内设计了与烃类反应相适应的工艺条件,可强化重油转化能力,减少干气和焦炭产率,从而提高总液体产品收率。     

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.     

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.     

Catalyst Deactivation, Kinetics, and Product Quality of Mild Hydrocracking of Bitumen-Derived Heavy Gas Oils

To assess mild hydrocracking as an option to improve the quality of the heavy gas oil (HGO) fraction of Syncrude's synthetic crude oil (known as Syncrude Sweet Blend or SSB), severe hydrotreating tests were performed by using Athabasca oilsands bitumen-derived coker HGO, heavy vacuum gas oil, and a blend of the two in a pilot-scale down-flow reactor over a typical commercial NiMo/Al₂O₃ hydrotreating catalyst. Kinetics of sulfur and nitrogen removal, 343°C+ conversion, and aromatics hydrogenation were investigated by incorporating the effect of catalyst deactivation. The total liquid products (TLPs) from the pilot tests were distilled into naphtha, light gas oil (LGO), and HGO fractions, and the TLPs and distilled products were characterized. Cetane number (CN) was determined by engine test for selected LGOs and by ignition quality tester for all LGOs. The quality of product HGOs as fluid catalytic cracking (FCC) unit feedstock was evaluated by using correlations (developed based on feed properties including GC-MS data) to predict FCC product yields. The CN of the LGOs and the predicted gasoline yields from HGO products were much better than that produced from the corresponding fractions of current SSB. The CN and FCC gasoline yield were related to the level of 343°C+ conversion (i.e., the higher the conversion, the higher the CN and FCC gasoline yield).     

催化裂化中温度对汽油裂解制备低碳烯烃的影响研究

对具有增产丙稀功能催化剂LCC-2,进行了高温裂解制备低碳烯烃试验。以催化汽油为原料,在中型提升管试验装置上进行了反应性能研究和反应温度的条件试验。结果表明:随反应温度的升高,汽油收率降低,干气产率增加,液化气产率随反应温度的升高先增加后下降,在600℃左右达到最大值;裂解产品中正构烷烃与异构烷烃降低,芳烃含量及辛烷值都有所增加。     

催化裂化—延迟焦化组合工艺

介绍了ＲＦＣＣ－延迟焦化组合工艺，ＲＦＣＣ应用了吸附转化加工焦化蜡油（ＤＮＣＣ）的技术。该组合工艺中的焦化汽油进ＲＦＣＣ改质，焦化蜡油注入ＲＦＣＣ提升管中部，ＲＦＣＣ油浆则作为延迟焦化的进料。结果表明，该组合工艺可改善产品分布，提高轻质油收率，焦化蜡油、催化裂化油浆、焦化汽油可以得到合理利用或改质，且可不产低价值的燃料油。     

催化裂化装置采用两段提升管技术的改造及效果

为降低催化裂化汽油烯烃含量和提高轻质油收率，对0.8 Mt/a重油催化裂化装置进行了采用两段提升管反应器催化裂化技术的改造。改造中除反应沉降器和提升管反应器改动较大外，其余设备改动很小。改造后装置采用了汽油回炼方式。改造后装置的标定结果表明，两段提升管反应器与LBO-16L降烯烃催化剂配合，在保证汽油烯烃体积分数小于35%的前提下，产品分布较好，轻质油收率和柴汽比较高。但是在汽油回炼量较大（20t/h）的情况下，汽油烯烃含量才达到要求。     

劣质重油高选择性催化裂化(RTC-G)技术开发

为了达到劣质重油催化裂化多产汽油和低碳烯烃的目的,基于拟全浓相、拟均温、拟匀速反应概念,提出使用快速流化床反应器对劣质重油原料进行催化裂化的思路。以中国石化济南分公司2号催化裂化装置原料油为原料,进行了快速流化床反应器催化裂化反应研究,开发了劣质重油原料高选择性催化裂化(RTC-G)技术。研究结果表明：相比于提升管反应器,使用快速流化床反应器催化裂化时的液化气产率和汽油产率分别高2.33百分点和0.35百分点,干气产率低0.34百分点,产品转化率和高价值产品选择性均有一定优势。在快速流化床反应器内选用适当的催化剂,可使劣质重油催化裂化的液化气产率达25.52%,丙烯产率达11.84%。     

FCC轻汽油组合回炼增产丙烯的研究

 以恒源石化提供的FCC轻汽油(LCG)和回炼油以及大庆炼油厂提供的蜡油(VGO)和常压渣油(AR)为原料,以自制LTB-2为催化剂, 在小型提升管装置中,研究了FCC轻汽油催化裂解增产丙烯的可行性以及与不同重质原料油组合进料对增产丙烯的协同效应.结果表明, LCG与回炼油、AR以及VGO组合进料回炼时,缩短了LCG的停留时间,在600℃、停留时间0.03s的反应条件下,干气产率明显降低,由9.94%～16.92%降到5.52%～6.33%,丙烯产率达到13.26%～17.91%,焦炭产率为0.69%～3.50%.     

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.     

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。     

FDFCC-Ⅲ装置加工不同性质原料油的技术分析

分析了中国石化洛阳分公司FDFCC-Ⅲ装置加工加氢精制蜡油前后的生产运行和生产调整情况。结果表明,重油提升管进料经过加氢精制处理后,性质得到明显改善,硫、氮、重金属等杂质含量大幅度降低;装置产品分布得到改善,干气、焦炭、油浆产率分别降低0.11,2.08,3.65个百分点,轻质油收率、总液体收率分别增加6.34和5.87个百分点;产品质量得到提升,汽油硫质量分数降到0.015%;装置能耗降低657 MJ/t;催化剂单耗降低0.4 kg/t。同时,充分利用汽油提升管改质降硫、降烯烃的作用,生产中通过优化汽油提升管混合进料品种、性质,在停开汽油选择性加氢装置的情况下,改质后汽油质量达到国Ⅲ标准要求,提高了装置整体运行水平。     

LDO-75重油催化裂化催化剂的工业应用

介绍了重油裂化催化剂LDO-75在中国石油独山子石化公司I套催化裂化装置上工业应用的情况。结果表明,当LDO-75催化剂达到系统藏量的80%后,与对比剂相比,油浆收率下降0.17百分点,同时,干气收率下降0.49百分点,总液体收率上升0.54百分点,轻油收率上升1.37百分点。由此可见,采用LDO-75催化剂时产品选择性好、轻油收率高、总液体收率高、重油转化能力强。LDO-75催化剂提高汽油辛烷值的能力强,与对比剂相比,汽油RON上升了1.9个单位,MON上升了1.6个单位,可达到提高汽油辛烷值生产高标号汽油的要求。     

提高汽、柴油收率的两段提升管催化裂化动力学模型研究及应用

 建立了提高汽、柴油收率的两段提升管催化裂化六集总动力学模型，根据小型提升管催化裂化装置的实验数据求取了动力学参数，并用Runge-Kuta方法对模型进行了求解。模型对两段提升管催化裂化技术进行计算的结果表明，一段的反应深度影响产品的产率和选择性，两段技术可以提高汽、柴油的产率，选择性和柴/汽比，降低干气和焦炭产率。与单段提升管催化裂化技术相比，当转化率为80%时，两段技术汽、柴油产率提高6.65%，选择性提高8.31%，柴/汽比由单段的0.71提高到1.07；当转化率为90%时，两段技术汽、柴油产率提高20.8%，选择性提高23.19%，柴/汽比提高到0.89。采用两段提升管技术，以汽、柴油作为目的产物时，汽、柴油的最大产率比单段提升管技术提高11.65%，选择性提高2.09%；以汽、柴油+液化气为目的产物时，汽、柴油+液化气的最大产率提高8.69%，汽、柴油的选择性提高16.87%，液化气的选择性则下降13.62%。     

MIP装置回炼轻汽油馏分增产丙烯的实施方案及效果

为降低成品油产量、增产丙烯,可将高烯烃含量轻汽油馏分送回MIP装置进行回炼。轻汽油回炼方式有4种：轻汽油走单独增设的回炼提升管回炼,轻汽油走急冷油线进MIP反应器变径提升管回炼,轻汽油进MIP提升管预提升段底部回炼,轻汽油进单独增设的喷嘴(在重油喷嘴下方)回炼。经对比分析发现：在重油喷嘴下方单独增设轻汽油喷嘴回炼,可以调控反应时间和反应深度;在尽量多产丙烯的前提下,轻汽油回炼产物分布合理、对MIP产品性质负面影响小、装置经济效益好,是优选的轻汽油回炼方式。