Investigation of the fluid catalytic cracking of different H-Oil vacuum gas oils and their blends with hydrotreated vacuum gas oil

H-Oil vacuum gas oils obtained during hydrocracking of vacuum residual oils originated from the crudes Russian Export Blend, Basrah light, and Heavy Kazakh were cracked in a mixture with a hydrotreated vacuum gas oil in the LUKOIL Neftohim Burgas commercial fluid catalytic cracking (FCC) unit. Some of the H-Oil vacuum gas oils were also cracked in a laboratory FCC (ACE) unit. The results from the commercial and the laboratory tests showed that the laboratory FCC experiments in an ACE unit can be used to evaluate the effect of feed quality on the commercial FCC unit performance. The assumption that the conversion of a vacuum gas oil (VGO) blend in the fluid catalytic cracking could be considered as a linear combination of the conversion of the individual components made by other researchers was also confirmed in this study. The higher the hydrogen content in the vacuum residual oil of a crude is the higher the FCC conversion of the H-Oil VGO, obtained during hydrocracking of that high saturate vacuum residual oil, will be expected.     

Advantages of Mild Hydrocracking FCC Feed—A Pilot Plant Study

Abstract

In view of increasingly stringent environmental regulations with respect to SOx and particulate emissions, the allowable sulphur and nitrogen levels in diesel and gasoline are reducing all over the world. Fluid catalytic cracking (FCC) unit is a major source of fuels produced from a refinery. Any attempt to reduce sulphur and nitrogen content of distillates produced from FCC unit will greatly improve the quality of fuels. In the present work, pilot plant studies were conducted to evaluate the options of hydrotreating and mild hydrocracking (MHC) of FCC feedstock. Experiments were conducted on commercially available catalyst samples using high nitrogenous vacuum gas oil (VGO) as feedstock. MAT experiments were also conducted to compare the conversions and yields of untreated, hydrotreated, and MHC VGO at constant operating conditions. Pilot plant data showed that MHC of VGO would produce additional fuels to the extent of 15% under moderate operating conditions besides improving the quality of FCC feedstock. The mild hydrocracked VGO as feed was found to increase FCC conversion by 2 wt%, increase fuels by 2.5 wt%, reduce residue by 2.8 wt% compared to untreated vacuum gas oil.     

Advantages of Mild Hydrocracking FCC Feed—A Pilot Plant Study

In view of increasingly stringent environmental regulations with respect to SOx and particulate emissions, the allowable sulphur and nitrogen levels in diesel and gasoline are reducing all over the world. Fluid catalytic cracking (FCC) unit is a major source of fuels produced from a refinery. Any attempt to reduce sulphur and nitrogen content of distillates produced from FCC unit will greatly improve the quality of fuels. In the present work, pilot plant studies were conducted to evaluate the options of hydrotreating and mild hydrocracking (MHC) of FCC feedstock. Experiments were conducted on commercially available catalyst samples using high nitrogenous vacuum gas oil (VGO) as feedstock. MAT experiments were also conducted to compare the conversions and yields of untreated, hydrotreated, and MHC VGO at constant operating conditions. Pilot plant data showed that MHC of VGO would produce additional fuels to the extent of 15% under moderate operating conditions besides improving the quality of FCC feedstock. The mild hydrocracked VGO as feed was found to increase FCC conversion by 2 wt%, increase fuels by 2.5 wt%, reduce residue by 2.8 wt% compared to untreated vacuum gas oil.     

INFLUENCE OF FEEDSTOCK COMPOSITION ON THE YIELD OF TOTAL CYCLE OIL IN FLUID CATALYTIC CRACKING

With a view to gaining an insight into the understanding of the factors responsible for the maximization of the total cycle oil (TCO) in the fluid catalytic cracking of the vacuum gas oils (VGOs) including the one from Bombay High (BH), necessitated by a greater demand for the diesel fuel compared to gasoline, in India, studies have been carried out on three different VGOs in a Xytel Auto Mat II unit over two REY based FCC catalysts differing in their zeolite content using a fixed bed reactor. The fact that the yield of CLO (370^°C+) from BH VGO was much higher than would be expected for a predominantly paraffinic feedstock has led to studying the cracking to compositionally different concentrates isolated from BH VGO and the results are discussed.     

Commercial Application of MGD Technology in FCCU Using VGO as Feedstock

MGD technology effectively integrates selective cracking reaction of olefin fraction in FCC naphtha with the stepwise cracking of light and heavy feedstocks under different severity conditions for improving FCC gasoline quality and adjusting the product slate of FCC unit. The first commercial application of MGD technology in a 1.30 Mt/a FCCU using VGO as feedstock at Tianjin Petrochemical Company showed that the olefin content in FCC naphtha decreased‘around 10 percentage points (by volume) with slight increase in octane number. The yields of LPG and LCO increased around 4.63 and 2.04 percentage points respectively, and the ratio between LCO to naphtha increased by 0.21. Due to capacity constraints of FCCU, the capacity decreased slightly under the MGD operation mode.     

INFLUENCE OF FEEDSTOCK COMPOSITION ON THE YIELD OF TOTAL CYCLE OIL IN FLUID CATALYTIC CRACKING

ABSTRACT

With a view to gaining an insight into the understanding of the factors responsible for the maximization of the total cycle oil (TCO) in the fluid catalytic cracking of the vacuum gas oils (VGOs) including the one from Bombay High (BH), necessitated by a greater demand for the diesel fuel compared to gasoline, in India, studies have been carried out on three different VGOs in a Xytel Auto Mat II unit over two REY based FCC catalysts differing in their zeolite content using a fixed bed reactor. The fact that the yield of CLO (370^°C+) from BH VGO was much higher than would be expected for a predominantly paraffinic feedstock has led to studying the cracking to compositionally different concentrates isolated from BH VGO and the results are discussed.     

蜡油加氢处理与催化裂化组合工艺的技术优化

中国石油化工股份有限公司洛阳分公司2.2 Mt/a蜡油加氢处理装置2009年5月建成投用,为催化裂化装置提供了优质蜡油原料,发挥了蜡油加氢处理与催化裂化组合工艺的优势.为进一步发挥该组合工艺潜力,采取蜡油加氢处理装置流程改造等优化措施,实现分馏系统停运,蜡油收率提高5.25百分点,有效提高了催化裂化装置处理能力,在降低蜡油加氢处理装置能耗的同时,改善了催化裂化产品分布,两套催化裂化轻质油收率分别提高1.20百分点和1.11百分点,汽油辛烷值提高了0.3个单位,经济效益显著.     

ATMOSPHERIC RESIDUE AS FEEDSTOCK TO HIGH-SEVERITY FLUID CATALYTIC CRACKING

The effect of atmospheric residue as a feedstock to a high-severity fluid catalytic cracking (HS-FCC) process has been investigated using a small-scale HS-FCC pilot plant (0.1 b/d) with a down flow reactor. This novel FCC process has been developed to enhance the yield of light olefins under high severity reaction conditions. Hydrotreated and virgin vacuum gas oils (VGO) as well as hydrotreated and virgin atmospheric residues (AR) were tested in the study. The yield of desired products such as gasoline and light olefins produced from virgin VGO cracking was 79 wt%, much higher than that obtained from a conventional FCC process whereas in case of hydrotreated VGO, the yield of desired products decreased to 76%. On the other hand, AR feeds exhibited performance similar to VGO with a slight increase in coke formation.     

ATMOSPHERIC RESIDUE AS FEEDSTOCK TO HIGH-SEVERITY FLUID CATALYTIC CRACKING

ABSTRACT

The effect of atmospheric residue as a feedstock to a high-severity fluid catalytic cracking (HS-FCC) process has been investigated using a small-scale HS-FCC pilot plant (0.1 b/d) with a down flow reactor. This novel FCC process has been developed to enhance the yield of light olefins under high severity reaction conditions. Hydrotreated and virgin vacuum gas oils (VGO) as well as hydrotreated and virgin atmospheric residues (AR) were tested in the study. The yield of desired products such as gasoline and light olefins produced from virgin VGO cracking was 79 wt%, much higher than that obtained from a conventional FCC process whereas in case of hydrotreated VGO, the yield of desired products decreased to 76%. On the other hand, AR feeds exhibited performance similar to VGO with a slight increase in coke formation.     

焦化汽油的催化裂化改质

报道焦化汽油催化裂化改质的工业试验结果,将11％－15％的焦化气油注入提升管预提升段与胜利管输VGO,CGO和VR混炼,经催化改质后,辛烷值可以达到90号汽油指标的要求,并可获得满意的产品分布,同时催化汽油的改质可明显降低催化汽油的烯烃含量,为焦化汽油利用找到了一条经济可行的途径。     

蜡油加氢装置高比例掺炼脱沥青油的可行性分析

分析了蜡油加氢装置掺炼溶剂脱沥青油(DMO)的情况,得知原料油中DMO掺炼比例增加后,装置脱硫率下降到70%以下,脱氮率下降到40%以下,调整反应温度后,装置脱硫率和脱氮率变化不明显。为解决高比例掺炼DMO的加工难题,开始是将加工路线调整为DMO不进蜡油加氢装置,直供催化裂化装置。结果显示,蜡油加氢装置脱硫率和脱氮率明显回升,但催化裂化装置汽油收率下降了5.69%,柴油收率上升了7.30%,企业效益下降。因此,DMO又重新改为进蜡油加氢装置,利用装置大检修调整反应器保护剂和主催化剂的装填量,结果表明,装置脱硫率和脱氮率能分别保持在约85%和50%,精制蜡油产品质量满足催化裂化装置的进料要求。     

Additional Feedstock for Fluid Catalytic Cracking Unit

Abstract

Fuel refineries are configured with Fluid Catalytic Cracking Unit (FCCU) to convert Vacuum Gas Oils (VGO) into higher value gasoline and middle distillates. But such refineries also generate 8–12% of heavy oils known either as decant oil or clarified oil (CLO), which has to be downgraded as furnace oil. The recycling of the decant oil into FCCU along with VGO feed is restricted to maintain the coke formation within design limits so that there is no decrease either in conversion or yield of liquid products from FCC operations. The condensed aromatic ring compounds present in CLO makes it undesirable feedstock for cracking, as it promotes heavy coke formation on the catalyst. Hence, CLO is disposed by absorbing in the residual fuel oils.

Of late, FCC units are being operated with higher severity to maximize gasoline, and this has resulted in much higher concentration of condensed aromatics in CLO. Hence, better utilization of CLO depends on separating its saturated hydrocarbon components as a good feedstock for recycling into FCCU with the simultaneous production of extract with enriched poly condensed aromatics as a value added product, namely Carbon Black Feed Stock (CBFS). This article describes several extraction studies carried out on CLO to obtain raffinate for which cracking studies were carried out in automated Micro Activity Test (MAT) unit. The quality of extract phase from each of the above studies was evaluated for its suitability as feedstock for carbon black.     

增产丙烯和生产清洁汽油组分技术的工业试验

在中国石油化工股份有限公司镇海炼油化工股份有限公司1.8M t/a的重油催化裂化装置上进行了增产丙烯和生产清洁汽油组分(M IP-CGP)技术的工业试验。工业试验结果表明,采用M IP-CGP技术,丙烯质量收率最高可达8.16%;汽油中的烯烃体积分数最低可降至18%以下。与原来采用的催化裂化工艺相比,汽油与原料油的硫含量(质量分数)之比下降50%~65%,辛烷值提高1.0~1.6个单位;总液体(液化气、汽油、柴油)质量收率约增加1%。该技术具有良好的技术经济效益和社会效益。     

加氢预处理对俄罗斯渣油催化裂化性能的影响

以硫、氮、金属含量及残炭均较高的俄罗斯减压渣油与减三线蜡油的混合油作原料,考察加氢预处理对渣油混合原料催化裂化性能的影响.结果表明:与未加氢预处理相比,混合原料加氢预处理所得大于350℃加氢渣油进行催化裂化时,产物的总液体收率提高4.41百分点,汽油收率提高5.74百分点,轻油收率提高5.12百分点,焦炭产率下降3.4...     

蜡油加氢预处理RVHT技术开发进展及工业应用

介绍了中国石化石油化工科学研究院的蜡油加氢预处理RVHT技术开发及工业应用情况。RVHT技术配套加氢处理催化剂RN-32V以及RVS-420具有优异的加氢脱硫脱氮反应性能。通过个性化的催化剂级配和反应工艺参数优化,可以拓宽RVHT技术的原料油适应性。应用RVHT技术生产催化裂化进料,可有效降低催化裂化进料-催化裂化汽油硫传递系数,为生产清洁汽油创造了有利条件。     

Additional Feedstock for Fluid Catalytic Cracking Unit

Fuel refineries are configured with Fluid Catalytic Cracking Unit (FCCU) to convert Vacuum Gas Oils (VGO) into higher value gasoline and middle distillates. But such refineries also generate 8-12% of heavy oils known either as decant oil or clarified oil (CLO), which has to be downgraded as furnace oil. The recycling of the decant oil into FCCU along with VGO feed is restricted to maintain the coke formation within design limits so that there is no decrease either in conversion or yield of liquid products from FCC operations. The condensed aromatic ring compounds present in CLO makes it undesirable feedstock for cracking, as it promotes heavy coke formation on the catalyst. Hence, CLO is disposed by absorbing in the residual fuel oils.

Of late, FCC units are being operated with higher severity to maximize gasoline, and this has resulted in much higher concentration of condensed aromatics in CLO. Hence, better utilization of CLO depends on separating its saturated hydrocarbon components as a good feedstock for recycling into FCCU with the simultaneous production of extract with enriched poly condensed aromatics as a value added product, namely Carbon Black Feed Stock (CBFS). This article describes several extraction studies carried out on CLO to obtain raffinate for which cracking studies were carried out in automated Micro Activity Test (MAT) unit. The quality of extract phase from each of the above studies was evaluated for its suitability as feedstock for carbon black.     

采用丙烷脱沥青工艺探讨催化裂化油浆的合理应用

在实验室现有的溶剂脱沥青装置上对催化裂化油浆进行丙烷脱沥青研究。结果发现油浆经过丙烷脱沥青后，大部分芳烃富集到脱油沥青中，使脱油沥青可作为较好的沥青调合组分；脱沥青油的n(氢）／n（碳）一般低于1．66，虽然其裂化能力较差，但由于脱沥青油作为原料催化裂化时的汽油产率低于VGO原料，而柴油产率大于VGO，因此，在VGO中掺炼部分脱沥青油可改变催化裂化的产物分布。     

5种催化裂化原料的裂化性能研究

利用XTL-5型提升管中试装置,对中国石油化工股份有限公司洛阳分公司催化裂化原料各组分的裂化性能进行了评价。结果表明:在完全相同的催化剂和操作条件下,减压蜡油、脱沥青油、常压重油、混合原料和拔头轻油浆的转化率分别为74.00%,69.91%,70.43%,67.16%和36.84%;其裂化性能从优到劣的顺序为:减压蜡油,脱沥青油(与常压重油相似),混合原料,拔头轻油浆;其中掺炼拔头轻油浆对催化进料的裂化性能影响很大,使催化裂化产品的分布明显变差。     

STUDIES ON FLUID CATALYTIC CRACKING OF HYDROPROCESSED FEEDSTOCKS

ABSTRACT

Worldwide public concern about environment and increased demand for better quality fuels by automobile industries has necessiated developed countries like USA, UK and Japan to stipulate stringent specifications for petroleum fuel products. Fluid catalytic cracking (FCC) is a major secondary process for fuel products and quality of products coming from FCC unit depends largely on the feedstock used. FCC naphtha makes up for 30–40% gasoline in a typical refinery pool. This FCC naphtha contributes to around 90% of the gasoline pool sulphur. Hence, sulfur and nitrogen reduction have become essential for meeting the quality requirements of fuel products resulting in the growing importance for pretreatment of FCC feedstock. In the present work, studies were carried out in pilot plant on hydrotreatment of feedstock for FCC unit. The results indicate better quality products for treated feedstock vis-a-vis untreated heavy vacuum gas oils from Persian Gulf (PG) crudes. Hydroprocessing of FCC feed has helped refiners in meeting the fuel products quality especially with feedstocks, which are characterized as heavy and refractory in nature.     

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%.