Application of Hydrocracking Process for Upgrading Tail Oil Quality in 1.0 Mt/a Hydrocracker Unit at SINOPEC Yangzi Petrochemical Company

This article focuses on the hydrocracking technology for upgrading the quality of tail oil and the first commercial application of the RN-32V/RHC- 1 catalysts in the 1.0 Mt/a hydrocracker at the Yangzi Petrochemical Company, which was started up successfully in September 2008. One month after start-up of the hydrocracking unit, an evaluation opera- tion has been conducted fbr assessing the catalysts performance. The technical calibration results showed that the RN- 32V/RHC-1 catalysts had high activity, and the product yield distribution was reasonable. The hydrocracker can provide abundant feedstocks for the downstream aromatic production unit and ethylene production unit.

Analysis of the Erosion-Corrosion Mechanism of the Air Cooler in a Hydrocracking Unit:A Numerical and Experimental Study

Corrosion leakages often occur in the air cooler of a hydrocracking unit,with the failure sites mainly located in the entrance area of the tubes.An analysis of the macroscopic morphology and corrosion products confirmed that the damage was caused by erosion-corrosion(E-C).Numerical and experimental methods were applied to investigate the E-C mechanism in the air cooler.Computational fluid dynamics(CFD)was used to calculate the hydrodynamic parameters of the air cooler.The results showed that there was a biased flow in the air cooler,which led to a significant increase in velocity,turbulent kinetic energy and wall shear within 0.2 m of the tube entrance.A visualization experiment was then performed to determine the principles of migration and transformation of multiphase flow in the air cooler tubes.Various flow patterns(pure droplet flow,mist flow,and annular flow)and their evolutionary processes were clearly depicted experimentally.The initiation mechanism and processes leading to the development of E-C in the air cooler were also determined.This study provided a comprehensive explanation for the E-C failures that occur in air coolers during operation.

Optimization of Hydrocracking Process for Enhanced BTX Production from Coal Tar-Derived Hydrorefined Products

Hydroconversion of coal tar to produce aromatic hydrocarbons(BTX)represents a crucial strategy for the highvalue hierarchical utilization of coal.This study focused on the hydrocracking of hydrorefined products derived from coal tar to enhance the production of benzene,toluene,and xylene(BTX).Various reaction conditions,including reaction temperature,hydrogen pressure,space velocity,and hydrogen-to-oil volume ratio,were systematically explored to optimize BTX yields while also considering the process’s economic feasibility.The results indicate that increasing the reaction temperature from 360℃ to 390℃ significantly favors the production of BTX,with yields increasing from 21.42%to 41.14%.Similarly,an increase in hydrogen pressure from 4 MPa to 6 MPa boosts BTX production,with yields rising from 36.31%to 41.14%.Reducing the space velocity from 2 h^(-1) to 0.5 h^(-1) also favors the BTX production process,with yields increasing from 37.96%to 45.13%.Furthermore,raising the hydrogen-to-oil volume ratio from 750 to 1500 improves BTX yields from 41.61%to 45.44%.Through economic analysis,the optimal conditions for BTX production were identified as a reaction temperature of 390℃,hydrogen pressure of 5-6 MPa,space velocity of 1 h^(-1),and hydrogen-to-oil volume ratio of 1000,achieving a BTX yield of 43.73%.This investigation highlights the importance of a holistic evaluation of hydrocracking conditions to optimize BTX production.Furthermore,the findings offer valuable insights for the design and operation of industrial hydrocracking processes aimed at efficiently converting coal tar-derived hydrorefined feedstock into BTX.

Effect of Catalyst Properties on Hydrocracking of Pyrolytic Lignin to Liquid Fuel in Supercritical Ethanol

The metal-acid bifunctional catalysts have been used for bio-oil upgrading and pyrolytic lignin hydrocracking. In this work, the effects of the metal-acid bifunctional catalyst prop- erties, including acidity, pore size and supported metal on hydrocracking of pyrolytic lignin in supercritical ethanol and hydrogen were investigated at 260 ℃. A series of catalysts were prepared and characterized by BET, XRD, and NHa-TPD techniques. The results showed that enhancing the acidity of the catalyst without metal can promote pyrolytic lignin poly- merization to form more solid and condensation to produce more water. The pore size of microporous catalyst was smaller than mesoporous catalyst. Together with strong acid- ity, it caused pyrolytic lignin further hydrocrack to numerous gas. Introducing Ru into acidic catalysts promoted pyrolytic lignin hydrocracking and inhibited the polymerization and condensation, which caused the yield of pyrolytic lignin liquefaction product to increase significantly. Therefore, bifunctional catalyst with high hydrocracking activity metal Ru supported on materials with acidic sites and mesopores was imperative to get satisfactory results for the conversion of pyrolytic lignin to liquid products under supercritical conditions and hydrogen atmosphere.

Optimization of the Striping Section of Modular Refinery Operations in Nigeria

Nigerian crude oil type Okoro 2012 was applied in this study owing to its low API value 23.54 and high residual percentage value of 42.16% from conventional modular refinery operations in Nigeria. The residue acted as a precursor or feedstock to the hydrocracker reactor of the modified modular refinery operation, which is an hydrogenation catalytic process at operating conditions of 380°C and 183 bar respectively and the hydrogen gas applied is produced via steam-methane reforming since the operational feedstocks are available as methane is the first gaseous product from the modified modular refinery process. Thus, more valuable products such as liquefied petroleum gas, naphtha and diesel were produced from modified modular refinery thereby resolving the residue or bottom product issue associated with conventional modular refinery operation in Nigeria. Models were developed from the first principle through the application of the principle of conservation of mass to predict the performance of the hydrocracker reactor and the developed models were sets of ordinary differential equations, which were solved using MatLab ODE45 solver and validated using simulation data of Aspen Hysys software for the hydrocracker reactor. The results gave a minimum percentage absolute error (deviation) between model predictions and Aspen Hysys results of 4.45%, 5.0% and 2.02% for liquefied petroleum gas, naphtha and diesel products respectively. Hence, the model developed predicted the output performance of the hydrocracker reactor very closely and was applied in studying or simulation of the effects of catalyst effectiveness factor on the overall performance of the hydrocracker reactor.

30,000 bpd Capacity Modified Modular Refinery Operations in Nigeria

The study investigated and classified twenty Nigerian crude oil types based on their products recovery volume at true boiling point temperature of 370&#730C using crude oil assay analysis data into Group A (crude oil with recovery volume above 80%), Group B (crude oil with recovery volume between 70% and 79%) and Group C (crude oil with recovery volume below 70%) respectively. Thus, twenty Nigerian crude oil types were simulated in a modified modular refinery (modified topping plant) of 30,000 bpd capacity and twenty-nine (29) column trays number using Aspen Hysys software. Furthermore, the residues from the conventional modular refinery were processed as feedstock or precursor into the hydrocracker reactor attached to the stripping section of the modified modular refinery to yield more valuable products of liquefied petroleum gas, naphtha, diesel and bottom (residue). The simulation results of the modified modular refinery were compared with conventional modular refinery in terms of their residual yield percentage as Nigerian Brass 2012 of API 40.62, recovery volume 88.78%, yielded residue of 11.22% and 1.29% for conventional modular and modified modular refineries respectively while Okoro 2012 of least API 23.54, recovery volume 57.84%, yielded residue of 42.16% and 4.92% for conventional modular and modified modular refineries respectively. Thus, the residual or bottom product issue associated with operational process of conventional modular refinery operations in Nigeria due to inefficient or non-operational conventional major refinery in Nigeria has been resolved to minimum or least amount with the operational process of modified modular refinery operations in Nigeria.

Synthesis,characterization and catalytic properties of Y-β zeolite composites

Y-β zeolite composites were hydrotherrnally synthesized by using high silica Y zeolite as the precursor and characterized by XRD, N2 adsorption, SEM and IR spectra of pyridine. The result showed that the N2 adsorption-desorption isotherm of the zeolite composites had a distinct hysteresis loop, and the SEM result showed that the zeolite composites had a different morphology from Y, β and the corresponding physical zeolite mixture. The acid catalytic performance of the zeolite composite catalysts was investigated in the hydrocracking and hydroisomerization of n-octane, and the results showed that the composite materials exhibited an excellent hydrocracking activity and good hydroisomerization performance. The yield of i-C4 over the zeolite composite catalyst was 4.45% higher than that on the corresponding zeolite mixture in the n-octane hydrocracking process at 553 K. The isomerization ability of n-octane over the composite catalyst was 3.6 fold that of the corresponding mixture at 503 K.

Selective hydrocracking of light cycle oil into high-octane gasoline over bi-functional catalysts

Light cycle oil(LCO) with high content of poly-aromatics was difficult to upgrade and convert,which had hindered upgrading fuel quality to meet with the standard of automotive diesel for the purpose of sustainable development.The hydrocracking behaviors of typical aromatics in LCO of naphthalene and tetralin were investigated over NiMo and CoMo catalysts.Several characterization methods including N2-adsoprtion and desorption,ammonia temperature-programmed desorption(NH3-TPD),Pyridine infrared spectroscopy(Py-IR),CO infrared spectroscopy(CO-IR),Raman and X-ray photoelectron spectroscopy(XPS) were applied to determine the properties of different catalysts.The results showed that CoMo catalyst with high concentration of S-edges could hydrosaturate more naphthalene to tetralin but exhibit lower yield of high-value light aromatics(carbon numbers less than 10) than NiMo catalyst.NiMo catalyst with high concentration of Mo-edges also presented a higher selectivity of converting naphthalene into cyclanes than CoMo catalyst.Subsequently,the naphthalene and LCO hydrocracking performances were also investigated over different catalysts systems.The activity evaluation and kinetic analysis results showed that the naphthalene hydrocracking conversion and the yield of light aromatics for CoMo-AY/NiMo-AY grading catalysts were higher than NiMo-AY/CoMo-AY grading catalysts at same condition.A stepwise reaction principle was proposed to explain the high efficiency of CoMo-AY/NiMoAY grading catalysts.Finally,the LCO hydrocracking evaluation results confirmed that CoMo-AY/NiMoAY catalysts grading system with low carbon deposition and high stability could remain high percentage of active phases,which was more efficient to convert LCO to high-octane gasoline.

Preparation of a new solid acid and its catalytic performance in di(1-naphthyl)methane hydrocracking

A new solid acid was prepared by trifluoromethanesulfonic acid （TFMSA） impregnation into an acid‐treated attapulgite （ATA）. Di（1‐naphthyl）methane （DNM） hydrocracking was used as the probe reaction to evaluate the catalytic performance of TFMSA/ATA for cleaving Car–Calk bridged bonds in coals. The results show that DNM was specifically hydrocracked to naphthalene and 1‐methylnaphthalene over TFMSA/ATA in methanol in the absence of gaseous hydrogen. In partic‐ular, TFMSA/ATA was demonstrated to be stable after four cycles with slight loss in catalytic activi‐ty. Furthermore, a proposed H＋transfer mechanism successfully interprets the TFMSA/ATA‐cata‐lyzed hydrocracking reaction of DNM.

Simulation of Low-Temperature Coal Tar Hydrocracking in Supercritical Gasoline

The aim of this paper was preliminary design of the process for low-temperature coal tar hydrocrackmg m supercritical gasoline based on Aspen Plus with the concept of energy self-sustainability. In order to ensure the correct- ness and accuracy of the simulation, we did the following tasks： selecting reasonable model compounds for low-tem- perature coal tar; describing the nature of products gasoline and diesel accurately; and confirming the proper property study method for each block by means of experience and trial. The purpose of energy self-sustainability could be pos- sibly achieved, on one hand, by using hot stream to preheat cold stream and achieving temperature control of streams, and on the other hand, by utilizing gas （byproduct of the coal tar hydrocracking） combustion reaction to provide energy. Results showed that the whole process could provide a positive net power of about 609 kW-h for processing the low- temperature coal tar with a flowrate of 2 268 kg/h. The total heat recovery amounted to 2 229 kW-h, among which 845 kW＇h was obtained from the gas combustion reaction, and 1 116 kW＇h was provided by the reactor＇s outlet stream, with the rest furnished by hot streams of the products gasoline, diesel and residue. In addition, the process flow sheet could achieve products separation well, and specifically the purity of product gasoline and diesel reached 97.2% and 100%, respectively.

Surface dealuminated Beta zeolites supported WO3 catalyst and its catalytic performance in tetralin hydrocracking

In this study,selective dealumination of Beta zeolites was performed through partially removing the templating agent in Beta zeolites by calcination and then removing the aluminum on the external surface of Beta zeolites with acid treatment.Hydrocracking catalysts were prepared by loading WO_(3)onto these dealuminated Beta zeolites.It was shown that the surface SiO_(2)/Al_(2)O_(3)of selectively dealuminated Beta zeolites was higher than that of conventionally dealuminated samples for the same bulk SiO_(2)/Al_(2)O_(3),and the hydrogenation activity of the catalyst of the selectively dealuminated Beta zeolites was lower than that of conventionally dealuminated Beta zeolites.The experimental results for tetralin hydrocracking to BTX showed that the catalysts based on the selectively dealuminated Beta zeolites had higher BTX selectivity and lower coke formation rate than that the catalysts based on the conventionally dealuminated Beta zeolites.

Hydrocracking diversity in n-dodecane isomerization on Pt/ZSM-22 and Pt/ZSM-23 catalysts and their catalytic performance for hydrodewaxing of lube base oil

Nobel metallic Pt/ZSM-22 and Pt/ZSM-23 catalysts were prepared for hydroisomerization of normal dodecane and hydrodewaxing of heavy waxy lube base oil.The hydroisomerization performance of n-dodecane indicated that the Pt/ZSM-23 catalyst preferred to crack the C-C bond near the middle of n-dodecane chain,while the Pt/ZSM-22 catalyst was favorable for breaking the carbon chain near the end of n-dodecane.As a result,more than 2%of light products(gas plus naphtha)and3%more of heavy lube base oil with low-pour point and high viscosity index were produced on Pt/ZSM-22 than those on Pt/ZSM-23 while using the heavy waxy vacuum distillate oil as feedstock.

A History of Fischer-Tropsch Wax Upgrading at BP-from Catalyst Screening Studies to Full Scale Demonstration in Alaska

Conversion of Fischer-Tropsch wax into high quality synthetic crude or finished transportation fuels such as premium diesel has been studied over the past 15 years within BP. Catalyst screening and selection was carried out in dedicated micro-reactors and pilot plants, whose designs are critical to the performance selection. Variation in catalyst composition and defining the gas to oil feed ratios with the operating temperature are a few of the parameters studied. Product selection and maximizing diesel yield combined with stability （catalyst life） were the ultimate drivers. The selected catalyst was then tested under commercial conditions in a dedicated 300 barrel per day demonstration plant. The products were also tested in engines to assess their combustion characteristics.

Application of Discrete Lumped Kinetic Modeling on Vacuum Gas Oil Hydrocracking

The kinetic model of vacuum gas oil （VGO） hydrocracking based on discrete lumped approach was investigated, and some improvement was put forward at the same time in this article. A parallel reaction scheme to describe the conver- sion of VGO into products （gases, gasoline, and diesel） proposed by Orochko was used. The different experimental data were analyzed statistically and then the product distribution and kinetic parameters were simulated by available data. Fur- thermore, the kinetic parameters were correlated based on the feed property, reaction temperature, and catalyst activity. An optimization code in Matlab 2011b was written to fine-me these parameters. The model had a favorable ability to predict the product distribution and there was a good agreement between the model predictions and experiment data. Hence, the ki- netic parameters indeed had something to do with feed properties, reaction temperature and catalyst activity.

Effect of preparation methods on the hydrocracking performance of NiMo/Al_(2)O_(3) catalysts

In this work,NiMo catalysts with various contents of MoO_(3)were prepared through incipient wetness impregnation by a twostep method(NMxA)and onepot method(NMxB).The catalysts were then characterized by XRD,XPS,NH3TPD,H_(2)TPR,HRTEM,and N_(2)adsorptiondesorption technologies.The performance of the NiMo/Al_(2)O_(3) catalysts was investigated by hydrocracking lowtemperature coal tar.When the MoO3 content was 15 wt%,the interaction between Ni species and Al_(2)O_(3) on the NM15B catalyst was stronger than that on the NM15A catalyst,resulting in the poor performance of the former.When the MoO^(3) content was 20 wt%,MoO_(3) agglomerated on the surface of the NM20A catalyst,leading to decreased number of active sites and specific surface area and reduced catalytic performance.The increase in the number of MoS_(2) stack layers strengthened the interaction between Ni and Mo species of the NM20B catalyst and consequently improved its catalytic performance.When the MoO_(3) content reached 25 wt%,the active metals agglomerated on the surface of the NiMo catalysts,thereby directly decreasing the number of active sites.In conclusion,the twostep method is suitable for preparing catalysts with large pore diameter and low MoO_(3) content loading,and the onepot method is more appropriate for preparing catalysts with large specific surface area and high MoO_(3) content.Moreover,the NMxA catalysts had larger average pore diameter than the NMxB catalysts and exhibited improved desulfurization performance.

Development and Application of Hydrocracking Catalysts RHC-1/RHC-5 for Maximizing High Quality Chemical Raw Materials Yield

To adapt to the change in the demand of the oil refining market,two hydrocracking catalysts,RHC-1 and RHC-5,were developed to improve the quality of tail oil.The catalysts were designed based on the theory of selective ring-opening.By selecting more acidic molecular sieves,the problem of poor selectivity of conventional materials can be solved to properly match up to the hydrogenation performance of catalysts.Compared with the performance of previous catalysts,the quality of the tail oil achieved by the said catalysts is better,and the BMCI is reduced by 1—2 units.In the long cycle operation of the petroleum industry,the good quality of the tail oil has been verified and the adaptability of the process conditions is good.When the RHC-1 catalyst is used to process heavy feed under medium pressure,a BMCI value of about12 can be obtained along with a nearly 60%yield of tail oil.The total yield of chemical raw material(steaming cracking feed+catalytic reforming feed)can exceed 80%,and the hydrogen consumption has dropped by nearly 50%as compared to the conventional hydrocracking conversion rate.When processing a mixed CGO and VGO feed with the full conversion mode under a hydrogen pressure of 13.0 MPa,the RHC-5 catalyst can yield about 68.4%of heavy naphtha with a potential aromatic content of up to 50.6,while the total yield of chemical raw materials can reach more than 98%.The results of industrial application of these catalysts show that more than 30%of high quality tail oil can be obtained via processing of inferior quality feed,and its BMCI value can reach 10.7.The total yield of chemical raw materials can reach more than65%.The industrial operation process has implemented two operating cycles totaling 8 years.

Investigation of the liquid recycle in the reactor cascade of an industrial scale ebullated bed hydrocracking unit

One of the commercial means to convert heavy oil residue is hydrocracking in an ebullated bed. The ebullated bed reactor includes a complex gas–liquid–solid backmixed system which attracts the attention of many scientists and research groups. This work is aimed at the calculation of the internal recycle flow rate and understanding its effect on other parameters of the ebullated bed. Measured data were collected from an industrial scale residual hydrocracking unit consisting of a cascade of three ebullated bed reactors. A simplified block model of the ebullated bed reactors was created in Aspen Plus and fed with measured data. For reaction yield calculation, a lumped kinetic model was used. The model was verified by comparing experimental and calculated distillation curves as well as the calculated and measured reactor inlet temperature. Influence of the feed rate on the recycle ratio(recycle to feed flow rate) was estimated. A relation between the recycle flow rate, pump pressure difference and catalyst inventory has been identified. The recycle ratio also affects the temperature gradient along the reactor cascade. Influence of the recycle ratio on the temperature gradient decreased with the cascade member order.

Commercial Application of the ICR Series Lube Isodewaxing Catalysts

This article illustrates the application of the ICR series lube oil isodewaxing catalysts in commercial scale and proposes the strategy on long cycle operation and optimization of catalysts. The results of commercial application of the catalyst have revealed that the catalyst after pretreatment including drying, sulfidation and reduction can process VGO into base oils meeting the HVI II and HVI II+ standards, and can manufacture base oils meeting the HVI III standard after incorporating the filtrate oil or gatch from acetone-benzene solvent dewaxing unit. The nitrogen content of the feed oil to the IDW reactor should be controlled at 1.0—1.5 ppm, while the CO and CO2 contents in fresh hydrogen is strictly controlled to avoid poisoning of the IDW-HDF catalysts.

Production of Quality Hydrogenated Base Oils through Isodewaxing Technology

This article presents the successful experience in adopting the Isodewaxing technology in the lube oil unit of Shanghai Gaoqiao refinery. In line with the demand of different crude slate for different reaction depth, and good match between the optimal product quality and the yield, the refinery has make strenuous efforts to optimize the operation and reduce the energy consumption to manufacture high-quality hydrogenated base stocks.

Novel design of lubricant-type vacuum distillation process for lube base oils production from hydrocracking tail oil

Dividing-wall columns(DWCs)are widely used in the separation of ternary mixtures,but rarely seen in the separation of petroleum fractions.This work develops two novel and energy-efficient designs of lubricant-type vacuum distillation process(LVDP)for the separation of hydroisomerization fractions(HIF)of a hydrocracking tail oil(HTO).First,the HTO hydroisomerization reaction is investigated in an experimental fixed-bed reactor to achieve the optimum liquid HIF by analyzing the impact of the operating conditions.A LVDP used for HIF separation is proposed and optimized.Subsequently,two thermal coupling intensified technologies,including side-stream(SC)and dividing-wall column(DWC),are combined with the LVDP to develop side-stream vacuum distillation process(SC-LVDP)and dividing-wall column vacuum distillation process(DWC-LVDP).The performance of LVDP,SC-LVDP,and DWC-LVDP are evaluated in terms of energy consumption,capital cost,total annual cost,product yields,and stripping steam consumption.The results demonstrates that the intensified processes,SC-LVDP and DWC-LVDP significantly decreases the energy consumption and capital cost compared with LVDP.DWC-LVDP further decreases in capital cost due to the removal of the side stripper and narrows the overlap between the third lube oils and fourth lube oils.This study attempts to combine DWC structure into the separation of petroleum fractions,and the proposed approach and the results presented provide an incentive for the industrial implementation of high-quality utilization of HTO through intensified LVDP.