Hydrocracking Reactor Research Articles

Process Simulation and Performance Models for Enhanced Modular Refinery Operations in Nigeria

The study aimed at availability of petroleum products in Nigeria through the operation of enhanced modular refinery process due to inefficient conventional major refineries. The enhanced modular refinery converts or processes residue product from conventional modular refinery as feedstock to the hydrocracker reactor for viable and desired products such as liquefied petroleum gas, naphtha and diesel. Therefore, twenty Nigerian crude oil types were classified as sweet, light and medium crude oil, and these crude oil types were categorized based on their recovery volume at true boiling point of 370oC as Group A, Group B and Group C respectively. Thus, based on product output and equipment cost, a modular refinery with 29 trays was used in this study, as light and medium sweet crude oil types were simulated in a modular refinery of various column trays prior to the desired tray. A topping plant with a 30,000 barrel per day capacity and a modified topping plant with 29 trays respectively were used to process different types of Nigerian crude oil. using Aspen Hysys to evaluate their products yield and tray compositions. The modified modular refinery with hydrocracker yielded more valuable from the residue of conventional modular refinery with minimal bottom fraction. Performance models for hydrocracker reactor was developed based on the nature of reaction, kinetic parameters estimated and results compared with experimental data with minimum deviations. The developed performance models predicted feedstock conversion and product yield along the hydrocracker reactor’s dimensionless length by solving a set of ordinary differential equation models. Thus, the hydrocracking process was simulated to evaluate the effects of catalyst effectiveness factor on feedstock conversion and products yield.

Novel distributed parameter model-based continuous lumping approach: An application to a pilot-plant hydrocracking reactor

A novel modelling approach that captures the complex chemistry of the hydrocracking process and its detailed solution is reported in this paper. The fundamentals of the developed model are coming from the well-known continuous lumping approach. The further development of the continuous lumping approach is that yield of each component in the different cracking reactions were estimated with three different yield distribution functions, moreover the originally applied skewed-Gaussian type yield distribution was reformulated and all three approaches were solved as partial differential equations. With the developed method not only the steady-state but the dynamic behaviour can be investigated. The unknown parameters of the models were estimated, and the model predictions were validated using previously published experimental data collected in pilot-plant VGO-hydrocracking reactor in Kuwait VGO at four severity levels. Based on the model error and predicted hydrocracking trends the skewed-Gaussian type yield distribution was the best for prediction.

Estimation of the gas hold up and flow regime of a bubble column reactor for the slurry phase hydrocracking of heavy oil

This study investigated gas hold up and flow regimes according to operating conditions (temperature, pressure, superficial gas velocity) for the design of a slurry phase hydrocracking reactor for heavy oil. Heating medium oil, vacuum residue (VR) and hydrocracking products were used in a bubble column reactor which had a diameter of 0.05 m and a height of 2.3 m. The results confirmed that the gas hold up increased and the flow regime transition point was delayed as VR was converted to a hydrocracking product (change in physical properties), and pressure also affected the flow regime transition. Using the dynamic gas disengagement method, the flow regime transition was observed in the actual hydrocracking reaction, and at the same time, it was confirmed that the hydrocracking reaction performance decreased. A VR slurry phase hydrocracking flow regime map is proposed by modifying the existing correlations, and a guide for reactor design and operation is suggested.

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.

Прогнозування залишкового ресурсу елементів конструкцій довготривалої експлуатації в екстремальних умовах (за матеріалами наукового повідомлення на засіданні Президії НАН України 23 грудня 2020 р.)

Applying the laws of thermodynamics, a general energy approach is formulated to study the delayed fracture of structural materials under the action of force load (static, cyclic, shunting mode of its change), high temperatures, hydrogen-corrosive media, neutron irradiation. Based on the energy approach process, models and forecasting methods of residual resource of structural elements in the mentioned operating conditions are developed. Based on the energy approach and the basic concepts of the acoustic-emission method, the calculation models in the parameters of the AE signals for the analytical description of the materials and structural elements delayed fracture under exploitation conditions are developed. Residual resource of the elements of power equipment (steam pipeline, elements of steam turbines), oil and gas pipelines, elements of nuclear power plants and the body of the oil hydrocracking reactor, is calculated.

Dynamic modeling and simulation of three-phase reactors for hydrocracking of vegetable oils

A dynamic, plug-flow, one-dimensional, and heterogeneous mathematical model for a trickle-bed reactor is described and used to simulate the catalytic hydrocracking of non-edible vegetable oil with countercurrent operation mode. The reactor model considers the hydrocracking reaction of triglycerides towards renewable fuels, which is present in the hydrotreatment process of vegetable oils. The dynamic model was first validated using experimental data reported in the literature, which were obtained in an isothermal micro-scale reactor with cocurrent downflow during hydrocracking of Jatropha oil over a commercial CoMo catalyst. Then, the three-phase reactor model was applied to predict the dynamic behavior of an industrial hydrocracking reactor in order to gain some insight into the transient behavior of the liquid molar concentration, partial pressure, and temperature profiles, which were obtained and discussed as a function of time and axial position of the catalytic bed. The simulations obtained with the proposed dynamic model showed good agreement with the experimental data and trends previously reported for the operation variables profiles at steady-state and relevant findings at industrial scale were obtained. One of the main challenges to produce biofuels by vegetable oils hydroprocessing is to control the high-temperature gradients along the catalyst bed because of the high reaction heat released; therefore, the development of dynamic trickle-bed reactor models, as shown in this work, can be used as a tool to predict the operational behavior of the unit under different reaction conditions and layouts to found the best scheme to control the effects by high-temperature rise.

Enhancement of Cobalt Concentration Supported on Mesoporous Silica towards the Characteristics and Activities of Catalysts for the Conversion of Waste Coconut Oil into Gasoline and Diesel Oil

The analysis of the effect of cobalt concentration supported on mesoporous silica (MS) has been evaluated. This study was aimed to observe the physical and chemical characteristics of the catalysts, and also to study the catalytic activity and its selectivity towards gasoline and diesel oil products in the hydrocracking process of waste coconut oil. The MS was produced using Lapindo mud, where the CTAB was used as the mesopore templating agent. The Co/MS catalyst was prepared by the wet impregnation method with various concentrations of Co. The characterization of the catalyst includes silica purity test by XRF, determination of Co content by AAS, the crystallinity by XRD, the catalyst porosity by SAA, physical pore structure by SEM and TEM, and total acidity by the gravimetric method using NH3 base vapor adsorption. The hydrocracking was carried out in a hydrocracking reactor using various concentrations of Co/MS catalysts with the ratio of catalyst/feed = 1/50. The products of the hydrocracking process were liquid, coke, and gas. The composition of the hydrocracking liquid products was analyzed by GC-MS. Based on the results of the catalytic activity test, it was concluded that the Co(1)/MS catalyst, which had the highest acidity, showed the best catalyst selectivity towards gasoline and diesel fractions.

Modeling of the Hydrocracking Reactor by the CESE Method

In this article, the improved space-time conservation element and solution element (CESE) method are used to simulate the dynamic treatment of the hydrocracking reactor. The dynamic model consists of four lumps: vacuum gas oil (VGO), middle distillate, naphtha, and gas which is dissolved by this method. The offered method can solve the partial differential equations caused by the reactions inside the hydrocracking reactor. In this study, both temperature and mole fraction variables are solved explicitly and simultaneously. In the CESE method, to obtain a suitable answer to the dynamic model, a CFL insensitive scheme was used which, for the CESE method to be stable, the CFL number should be less than 1. In this work, obtained results from the CESE method, in good agreement with the data industry. Outcomes illustrate that AAD% of the yield forecast for the middle distillate, naphtha, and gas are 3.33%, 2.56 %, and 6.47%, respectively. This method unlike other contractual numerical methods treats with space and time coordinates Similar.

Modeling and Simulation of Reaction and Fractionation Systems for the Industrial Residue Hydrotreating Process

The residue hydrotreating process plays a significant role in the petroleum refining industry. In this process, modeling and simulation have critical importance for process development, control, and optimization. However, there is a lack of relevant reports of plant scale due to complexity in characterizing feedstock and determining reaction mechanisms. In this paper, reaction and fractionation models are constructed and simulated for a real-life industrial residue hydrotreating process based on Aspen HYSYS/Refining. Considering the heavier and inferior residue, analytical characterization is carried out for feedstock characterization based on laboratory analysis data. Moreover, two reactor models with parallel structures are proposed to implement the intricate reaction network, namely, a hydrocracker reactor and a plug flow reactor. The former simulates lighter petroleum hydrotreating based on the built-in reaction network. The latter emulates the conversion of a peculiar, heavier resin and asphaltene, using a six-lump model, which expands the scope of the feedstock and improves the accuracy of the model. To obtain a realistic simulation of fractionation, the database-based delumping method is adopted to model it with proper pseudo-components. The simulation results, including temperature rise, hydrogen consumption, temperature distribution, product yield, product properties, indicate that the model is capable of reflecting the realistic process accurately.

Evaluation of Polycyclic Aromatic Hydrocarbon Removal from Hydrocracking Recycle Streams

Large polycyclic aromatic hydrocarbon (PAH) compounds with 7 or more rings, such as coronene, can be problematic in petroleum refining processes, where they build up over time and eventually enhance coke formation. In this work, large PAH molecules were characterized in a recycling stream returning the distillation bottoms of a commercial hydrocracking reactor back into the unit. High performance liquid chromatography and Fourier transform-ion cyclotron resonance mass spectrometry (FT-ICR MS) methods were in good agreement on PAH compounds extracted with DMSO, which provided a selective way to determine PAH with up to 10 aromatic rings. However, after Soxhlet extraction with pentane PAH compounds with up to 14 aromatic rings were tentatively identified using FT-ICR MS, extending the naphthalene zig-zag pattern. With the characterization method established, solvent extraction, solvent precipitation, and adsorption processes were tested to remove the problematic, large PAH compounds from the recycle stream....

AKTIVITAS DAN SELEKTIVITAS KATALIS Ni/H5NZA TERHADAP HIDRORENGKAH METIL OLEAT MENJADI SENYAWA HIDROKARBON FRAKSI PENDEK

It has conducted on the activity and selectivity of Ni/H5NZA catalyst toward the hydrocracking of oleat methyl catalytic becomes short fraction hydrocarbon compounds with the variation of Ni concentration such as 1%, 2% and 3% (% w/w) for oleat methyl catalytic hydrocracking becomes short fraction hydrocarbon compounds (C5-C11 hydrocarbon). The catalyst is prepared by wet impregnation method, then followed by calcinations at 500oC, oxidation at 400oC and reduction at 500oC, each of them are followed by a stream of nitrogen, oxygen and hydrogen with ± 5mL/second in stream velocity. The characterization of catalyst includes the determination of Si/Al ratio, Ni metal that were impregnated by using AAS instrument, and the acid determination by using gravimetric method. The hydrocracking process is done in flow-fixed bed reactor at 500oC; the catalyst are heated at first and followed by the reactants which are heated in pyrolysis reactor up to it change into vapor, then they are moved into the hydrocracking reactor. The liquid from hydrocracking process is collected and analyzed by using Gas of Chromatography (GC) and Gas of Chromatography-Mass spectrometer (GC-MS). The characterization results showed in general that Si/Al ratio decreases after being impregnated by Ni metal. The amount of Ni metal almost reach a half of early Ni concentration which is impregnated. On the other hands, the acid amount of catalyst after being impregnated by Ni metal rise higher than those before being impregnated by Ni metal. The research showed that the activity and selectivity of Ni-2%/H5NZA catalyst is better in hydrocracking hydrocarbon compounds which are shorter. The activity of Ni-2%/H5NZA catalyst reaches 91.3041%. Meanwhile the selectivity is more selective in creating the hydrocarbon compounds with C5-C11 chain and more lead to the formation of alkane and alkene. Keywords: methyloleate, catalyst, Ni/H5NZ,hydrocracking

Simulation, exergy analysis and optimization of a shale oil hydrogenation process for clean fuels production

Because of high contents of unsaturated hydrocarbons, sulfur, nitrogen and other impurities in shale oil, its potential use as an alternative fuel is limited. Shale oil hydrogenation technology is an efficient technique for upgrading shale oil to remove heteroatomic compounds. The whole shale oil hydrogenation process is modeled and simulated firstly in this paper, including embedding the kinetic models of hydrogenation reactions. The corresponding-state group contribution method is applied to estimate the physical properties of the components of shale oil. The performance of the shale oil hydrogenation process is analyzed by exergy analysis. The results indicate that the exergy efficiency of the shale oil hydrogenation process is about 69.20%. The energy bottleneck is the furnaces and compressors because the energy consumption of these devices is 59% and 24% of that of the shale oil hydrogenation process. Furthermore, to optimize the performance of this process, the key parameters of the process are investigated and optimized. The preferable reaction temperature of the hydrorefining and the hydrocracking reactors is 350–375 °C and 375–400 °C. The reaction pressure and catalyst grading ratio are suggested to 16–17 MPa and 1:3:3 for maximizing the yield of products with ultra-low nitrogen and heteroatomic compounds.

Effect of welding thermal cycle on structural and phase weld metal transformations for heat-resistant Cr–Mo–V steels

Results are presented for dilatometric and metallographic investigations and determination of microhardness for weld metal made of the materials for the automatic welding of VVER reactor vessels and oil hydrocracking reactor vessels. It is found that small differences in the content of alloying elements, such as nickel, chromium, molybdenum, and vanadium, cause differences in the structure of the weld metal before heat treatment.

A new lumped kinetic model of an industrial hydrocracking process

Hydrocracking is a catalytic cracking process for the conversion of heavy oil fractions, such as vacuum gas oil (VGO), into valuable products with lower boiling point, such as diesel, kerosene and gasoline. Due to the flexibility of the process, high yields and good quality of liquid products, hydrocracking has become an important unit in modern refinery. However, the study of kinetic modelling towards hydrocracking reactor (HCR) is limited due to its complicated reaction mechanism. In this study, the reactor model is established based on a new six-lump model considering the velocity change along the reactor, different thermal effects and kinetic differences between hydrotreater (HT) and hydrocracker (HC). Compared with the previously reported lumped kinetic models, the fine-tuned model (calibrated by differential evolution algorithm) can predict products yields more accurately, in particular outlet temperature of each beds and the detailed yields and temperature distribution along with the reactor beds. The proposed lump based kinetic model can be applied to the optimization and control of industrial hydrocracking process.

Fischer-Tropsch biofuels production from syngas obtained by supercritical water reforming of the bio-oil aqueous phase

A new process to produce low-temperature Fischer-Tropsch products from the syngas obtained by supercritical water reforming technology of the bio-oil aqueous phase is developed and analyzed. The process includes four sections: syngas production from supercritical water reforming, syngas upgrading by water–gas-shift and dry reforming reactors as well as pressure swing adsorption systems, Fischer-Tropsch synthesis and products refining and upgrading through a distillation columns train and hydrocracking reactor. The aim is to produce maximum biofuels and electrical power, achieving the overall energy self-sufficiency. The energy scheme also involves cogeneration (e.g., hot water for district heating) and removal of CO2 for sequestration. Process simulations were carried out by Aspen Plus. The effect of the main operating parameters (feed concentration and composition, as well as operating conditions of Fischer-Tropsch reactor) on the process performance (carbon efficiency with or without refining, biofuel and electricity production) was studied by a sensitivity analysis. This way, the optimal conditions were found, so for a feeding of 60t/h with a total organic concentration of 35wt%, carbon efficiency with refining is 38.5% (4.6t/h biofuel) and 5.3MWe is generated. The CO2 for sequestration is 0.50kg/kg of organic feeding.

Parametric study of two-stage hydropyrolysis of lignocellulosic biomass for production of gaseous and light aromatic hydrocarbons

Non-catalytic hydropyrolysis of pinewood and its components was carried out using a two-stage reactor. The main aim of this work is to investigate the hydrodeoxygenation and hydrogenation of volatile matter in the post hydrocracking reactor for oriented production of gaseous and light aromatic hydrocarbons. A portion of volatile matter, which evolved from hemicellulose, neutral extractives and lignin below 275°C, was found to be thoroughly hydrodeoxygenated preventing the release of CO2 and CO. Increasing hydrocracking temperature from 600°C to 750°C and pressure from 1.0MPa to 5.0MPa strongly facilitated the hydrogenation reactions to target products. The summed yield of CH4 and C2H6 (dry biomass basis) reached up to 33.2% at a hydrocracking temperature of 750°C and 5.0MPa, with a concomitant 5.1% yield of BTX. All components in pinewood significantly contributed to the production of CH4 and BTX by hydropyrolysis, differing from the case of pyrolysis.

Hydrocracking Kinetics of a Heavy Crude Oil on a Liquid Catalyst

Heavy crude oil hydrocracking was carried out in a continuous reactor using a liquid acid catalyst. Experiments were conducted at 100 kg/cm2 pressure, a low to moderate reaction temperature (350 and 370 °C), and a hydrogen/hydrocarbon ratio of 10 m3/barrel for 180 h. The reaction temperature was below typical industrial hydrocracking reactors to avoid coke or sediment formation. Experimental results demonstrated that heavy oil was importantly upgraded, hydrocracked oil was less viscous, lighter, and with a higher content of valuable distillates than the original heavy crude oil. Kinetics of the process based on a five lump reaction scheme was determined using a modified Marquard–Levenberg optimization technique. The experimental and calculated yield comparison for each of the lumps is in close agreement.

Dynamic modeling of adiabatic reactor for hydrocracking of VGO by using of the continuous lumping approach

The dynamic modeling of an adiabatic hydrocracking reactor was carried out by using the continuous lumping approach. Vacuum gas oil with 30.6°API and normal boiling temperature range from ~285°C to about 329°C was used as feedstock. Kinetic model parameters were derived from experimental information at three different reactor temperatures: 360, 370, and 380°C; 1–3h−1 LSHV; 356m3/m3 hydrogen-to-oil ratio, and reactor pressure of 5.3MPa. Thermal correlations were chosen to be reliable and dependent on reactivity index. The simulations allowed predicting the dynamic behavior of the reactor regarding temperature and cumulative weight fraction profiles. At the reaction conditions of simulations an increase of almost 10°C was observed in the bed regarding inlet temperature while the reactor position of such maximum was moved to outlet reactor as time-on-stream increased.

A two-dimensional discrete lumped model for a trickle-bed vacuum gas oil hydrocracking reactor

A two-dimensional (2D) computational fluid dynamics model based on discrete lumping approach was used to predict the product yields of a pilot scale vacuum gas oil (VGO) hydrocracking reactor. This model was developed by solving mass conservation equations in conjunction with the continuity and momentum balances in the z-r cylindrical plane. The kinetic parameters of the model were estimated from the experimental data, and validated by using actual values. Results show that the proposed model can appreciably improve the accuracy of the yield prediction in comparison to the predicted value using the 1D model. Moreover, it is confirmed that the order of magnitude of the radial liquid velocity against the axial one is considerably low, and there is no significant pressure drop along the r-direction. Additionally, results show that two-dimensional model is a reliable tool for evaluating the catalyst performance and also for designing commercial reactors.