Light Naphtha Isomerization Research Articles

Evaluation of Synthesized Pt/HY-H- Mordenite Composite Catalyst for Isomerization of Light Naphtha

This work deals with a composite catalyst preparation, Pt/HY-H-Mordenite, for isomerization of Iraqi light naphtha produced from Baiji North Refinery in a pilot plant fixed bed reactor under operating conditions with the following ranges: temperature 150–250 °C, LHSV 2.46–4.7 hr-1, pressure 6 bar, and hydrogen to hydrocarbon ratio 3.7 mol/mol. The prepared nano-silica, Na-mordenite, H-mordenite, and Pt/HY-H-Mordenite catalysts were described by X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), Fourier transform infrared spectroscopy (FTIR), and Brunauer-Emmett-Teller (BET) surface area analysis. The investigation results showed that the light naphtha isomerization conversion and yield increased with increasing the temperature and decreasing the liquid-hour space velocity. The highest conversion and yield, obtained at 250 °C and LHSV of 2.46 hr-1, were 89.38% and 76.36%, respectively.

Kinetic Modeling of Light Naphtha Hydroisomerization in an Industrial Universal Oil Products Penex™ Unit

Recently, the isomerization of light naphtha has been increasingly significant in assisting refiners in meeting sternness specifications for gasoline. Isomerization process provides refiners with the advantage of reducing sulfur, olefin, and benzene in the gasoline basin without significantly victimizing the octane. The mathematical modeling of a chemical reaction is a critical tool due to it can used to optimize the experimental data to estimate the optimum operating conditions for industrial reactors. This paper describes light naphtha isomerization reactions over a Pt/Al₂O₃-Cl catalyst at the Al-Dura Oil Refinery (Baghdad, Iraq) using a newly developed universal mathematical model. The proposed kinetic model involves 117 isomerization reactions and 90 cracking reactions to describe 52 real components graded from methane to n-octane. A Genetic Algorithm stochastic optimization technique applied in MATLAB R2020a software was employed to estimate the optimal set of kinetic parameters. The calculated activation energies for hydrocracking reactions was found to be higher than the other reactions because of hydrocracking reactions occur at higher range of temperatures. By benchmarking between the experimental and theoretical results for all 117 data sets, the mean absolute error was obtained to be 0.00360 for all 52 components. Also, a positive effect of increasing reaction temperatures was recognized on enhancing the research octane number (RON).

Robust prediction and optimization of gasoline quality using data-driven adaptive modeling for a light naphtha isomerization reactor

• A data-driven adaptive modeling was made for a light naphtha isomerization reactor. • A new integrated machine learning model (i.e., DLS-SVR) was proposed. • DLS-SVR model shows a better predictive peformance than RSM, SVR, and DLWELM models. • RON, RVP, and benzene content of the isomerate gasoline can be robustly predicted. • Gasoline quality was optimized using a combination of DLS-SVR and CPSO algorithm. In this research, a data-driven adaptive model is developed to predict the variables indicating gasoline quality in the light naphtha isomerization process and determine the optimal conditions leading to improved gasoline quality. To this end, an integrated method based on double-level similarity criterion and support vector regression (DLS-SVR) is proposed. The variables that indicate gasoline quality are research octane number (RON), benzene volume percentage (BVP), and Reid vapor pressure (RVP). In addition to the influential operating variables of pressure, temperature, feed weight hourly space velocity (WHSV), and hydrogen to naphtha feed molar ratio, the model considers benzene’s feed concentration and cycloparaffin content. Experiments are conducted using commercial Pt/Al 2 O 3 -CCl 4 catalyst in a pilot-scale packed-bed reactor. The developed model’s predictive performance and generalization ability are compared with the response surface methodology, support vector regression, and double-level locally weighted extreme learning machine through the fivefold cross-validation technique. The generalized DLS-SVR predicts gasoline’s RON, BVP, and RVP with R 2 = 0.901, 0.959, and 0.931 and RMSE = 0.055, 0.061, and 0.053, respectively, indicating that its performance is superior to alternative generalized models. The optimal conditions are computed using the DLS-SVR model and co-evolutionary particle swarm optimization algorithm (CPSO). The optimal operation of the reactor yielded a 6.78-unit increase in gasoline RON and a minimum BVP of 0.394 %. The results demonstrate that the proposed DLS-SVR model can accurately predict the variables indicating the quality of isomerate gasoline.

Development of a dimensionless and dynamic model of the three-phase trickle bed reactor in light naphtha isomerization process: effects of axial mass dispersion and liquid-solid mass transfer on isomers concentration

Abstract This study develops a general dimensionless model for a three-phase trickle bed reactor in the light naphtha isomerization process. The simulations are accomplished to study its conduct. The model brings up a one-dimensional axial dispersed flow to characterize dispersity and liquid-solid mass transfer in the forms of dimensionless Peclet and mass Stanton numbers under adiabatic conditions. It considers the essential reactions extant in the isomerization process comprising isomerization, hydrogenation, and hydrocracking reactions applying a precise approach of dimensionless kinetic equations and rate constants. The Crank–Nicolson method and a nonstandard finite difference approach are utilized for large systems of time-spatial PDEs to resolve the dynamic reactor model with MATLAB software. The aim is to elucidate how these large systems of PDEs and nonlinear ODEs can be solved with a comprehensive computation in the form of physical dimensionless numbers. The isomers compositions estimated with the suggested model are in corroboration simulation results obtained by empirical information. The dynamics are evaluated to consider the system conduct with a variation in the hydrogen concentration of the feedstock.

Synthesis and Characterization of Sulfated Zirconia Catalyst for Light Naphtha Isomerization Process

The platinum-loaded zirconium oxide (Pt/SO4-2/ZrO2) catalyst was developed for the light naphtha atoms over the reaction temperature range of 160 to 220 °C, 1 and 3 h-1 LSHV and 10 bar. Platinum improved the stability of the catalyst by preventing the formation of a coke precursor at the strong acid site of sulfur zirconium. The acidity of the catalyst was characterized by of NH3-TPD and the effect of sulfur and calcination temperature on the surface area of ​​the final prepared zirconia was studied. The prepared catalyst shows high structural similar activity at temperature between 200 and 210°C for two types of light naphtha feed.

Impacts of Alumina Introduction on a Pt–SO4/ZrO2 Catalyst in Light Naphtha Isomerization

Impacts of Alumina Introduction on a Pt–SO₄/ZrO₂ Catalyst in Light Naphtha Isomerization

Synthesis and Characterization of Ni-WO3/Sulfated Zirconia Nano catalyst for Isomerization of N-Hexane and Iraqi Light Naphtha

This work deals with preparation of Sulfated Zirconia catalyst (SZ) for isomerization of n-hexane model and refinery light naphtha, as well as enhanced the role of promoters to get the target with the mild condition, stability, and to prevent formation of coke precursors on strong acidic sites of the catalyst. The prepared SZ catalysts were characterization by fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), Brunauer –Emmett-Teller (BET) surface area analysis, Thermogravimetric Analysis (TGA), Scanning Electron Microscope (SEM) and atomic force microscopy (AFM) Analyzer. The results illustrate that the maximum conversion and selectivity for n-hexane isomerization with Ni-WSZ and operating temperature of 150 °C was 80.1% and 96 % respectively .Other set of experimental with light naphtha , the results show that the maximum conversion and selectivity with Ni-WSZ and operating temperature of 150 °C was 73.6% and 74% respectively.

Deactivation of platinum on chlorinated alumina catalyst in the light naphtha isomerization process

In order to maintain and increase the lifetime of platinum on chlorinated alumina catalyst, its deactivation was investigated in the presence of oxygenated compounds or mercaptans in the light naphtha hydroisomerization process. A high concentration of methanol or dimethyl disulfide (DMDS) in the feed resulted in irreversible and reversible deactivation of the catalyst. The degree of deactivation and activity recovery of the catalysts measured in the light naphtha isomerization and benzene hydrogenation reactions. The experimental results indicated that when the catalyst was deactivated with oxygenated compounds such as methanol, the catalyst activity was lost drastically, and the regeneration treatment was unable to restore the catalyst’s initial activity. However, a full recovery of the catalyst may obtain when deactivation occurred with dimethyl disulfide. It found that oxygenated compounds affect the acidic functional groups, but mercaptans had an important influence on metallic sites of the catalyst.

A detailed reaction kinetic model of light naphtha isomerization on Pt/zeolite catalyst

There is increasing interest in kinetic models of catalytic refining processes, because of their importance in developing and improving these processes. In fact, the models can be used to predict process performance parameters and to determine the optimum operating conditions. In this work, a detailed reaction kinetic model was developed to describe light naphtha isomerisation reactions over different Pt/zeolite catalysts (Pt/mordenite, Pt/ZSM5, and Pt/BETA). The proposed kinetic model included 66 isomerisation, 28 ring opening, 1 olefin saturation, 22 dehydrogenation, and 90 hydrocracking reactions for 52 real light naphtha components graded from methane to n-octane. A power law reaction kinetics was assumed for all reactions, and 414 kinetic parameters were fine-tuned by comparing the predictions of the model with the results of light naphtha isomerisation experiments at six different temperatures (290, 310, 330, 350, 370, and 390 °C). The Matlab software (version 2015a) was used to perform all the calculations in the current study, and the optimum set of kinetic parameters was estimated using genetic algorithm optimisation. The mean absolute errors for all component compositions at different temperatures were found to be 0.003608, 0.004841, and 0.004757 for the Pt/mordenite, Pt/ZSM5, and Pt/BETA catalysts, respectively. The values of the mean absolute errors estimated from the comparison between the experimental and predicted results showed a very good agreement between the model predictions and the experimental data.

Optimization approaches to the integrated system of catalytic reforming and isomerization processes in petroleum refinery

In this paper, we deal with the optimization of a cluster comprising two key processes in petroleum refinery: catalytic reforming, and light naphtha isomerization. We propose a novel hybrid methodology which combines direct and indirect approaches. In the direct approach we consider the complete kinetic model and we adopt derivative-free approaches since the analytic expression of the model is not available. In the indirect approach we propose a surrogate modelling based optimization and we apply state-of-the-art solver to retrieve the optimal operating condition and flowsheet configuration of the process. The hybrid method consists of two steps: (i) we compute different good feasible solutions by means of the indirect approach, and (ii) we apply the direct approach using the solutions of the previous step as starting points. Computational experiments for different scenarios are finally discussed.

ТЕХНОЛОГИИ ИЗОМЕРИЗАЦИИ ЛЁГКОГО УГЛЕВОДОРОДНОГО СЫРЬЯ В ПРАКТИКЕ ПЕРЕРАБОТКИ НЕФТИ

The features of high-, medium- and low-temperature processes of light naphtha isomerization, operating conditions of the used catalysts and quality specification of the feedstock’s are considered.

ПРОБЛЕМЫ ПРОЦЕССА ВЫДЕЛЕНИЯ УЗКОЙ ФРАКЦИИ С5 - С6 В ТЕХНОЛОГИИ ИЗОМЕРИЗАЦИИ ЛЕГКОЙ НАФТЫ

Approaches of problem points estimation for increasing productivity and increasing the accuracy of isolating the C5-C6 fraction in light naphtha isomerization technology are considered. It is shown that the elimination of these problem points is possible by increasing the efficiency of existing internal contact devices of the distillation column, or by increasing the efficiency of the furnace. The final solution to the problem should be determined on the basis of mathematical modeling of the process.

Surrogate-based modeling techniques with application to catalytic reforming and isomerization processes

In this paper, we first briefly survey the main surrogate model building approaches discussed in the literature considering also design of experiments strategies and dimensionality reduction procedures: we mainly focus on sub-set approaches and sampling strategies for constrained regression problems. We delineate a systematic methodology for surrogate modelling in presence of model constraints, such as non-negativity of the model responses. The main contribution of this paper is twofold: from one side we extend the principal component analysis framework to the case of constrained regression problem, from the other we propose a novel methodology which integrates the subset selection and the previous principal component regression procedure. Finally, we apply the two novel algorithms to two fundamental chemical processes in petroleum refinery, namely catalytic reforming and light naphtha isomerization. The numerical results show the comparisons between the two algorithms in terms of computational and accuracy trade-offs.

Experimental Study of Iraqi Light Naphtha Isomerization over Ni-Pt/H-Mordenite

Hydroisomerization of Iraqi light naphtha was studied on prepared Ni-Pt/H-mordenite catalyst at a temperature range of 220-300°C, hydrogen to hydrocarbon molar ratio of 3.7, liquid hourly space velocity (LHSV) 1 hr-1 and at atmospheric pressure.
 The result shows that the hydrisomerization of light naphtha increases with the increase in reaction temperature at constant LHSV. However, above 270 0C the isomers formation decreases and the reaction is shifted towards the hydrocracking reaction, a higher octane number of naphtha was formed at 270 °C.

A multi-Response Optimization for Isomerization of light Naphtha

Isomerization process is considered one of the main processes used to produce high octane rating gasoline with improved environmental conditions and less emissions. The main keys of performance in isomerization units are the product yield, paraffin isomerization number (PIN) and octane number (RON). In this article we present a multi-response optimization strategy for an industrial naphtha continuous isomerizationprocess that aims to maximize RON, PIN and yield. Data of 53-runs including feed compositions as well as operating conditions; reactor temperature, benzene content, liquid hour space velocity, feed PIN, hydrogen to hydrocarbon ratio, feed octane number, C7+ content, inlet reactor temperature and iC5/C5P ratio are collected from a refinery company over a period of two months to test the effect of each variable and their interaction over each response individually using analysis of variance (ANOVA). Model reduction is applied for the three models in order to exclude any insignificant data and improve the model’s accuracy. Finally, the optimum operating conditions for the process are selected using numerical optimization in Design Expert 11 by comparing with the real industrial data runs to give the maximum yield, PIN and RON which are 99.992, 122 and 86 respectively. Benzene content is selected to be 1.807 wt%, reactor temperature;143oC, LHSV; 0.882 h-1, feed PIN; 64.611, H2/HC; 0.07, feed RON; 74.408, C7+; 4.06 wt%, inlet reactor temperature; 116oC and iC5/C5P ratio 45.768.

Effect of acidity and porosity changes of dealuminated mordenite on n-pentane, n-hexane and light naphtha isomerization

Abstract The purpose of this research work is to prepare and assess the catalytic performance of platinum (Pt) dealuminated mordenite for the of n-hexane, n-pentane and light naphtha isomerization. The Pt dealuminated mordenite was prepared by dealumination of commercial mordenite catalyst by refluxing using hydrochloric acid at 100 °C in various time durations (0.50, 1.0, and 3.0 h). The commercial as well as dealuminated mordenite catalysts were examined by X-ray diffraction analysis, X-ray fluorescence, N2 adsorption-desorption, Fourier-transform infrared spectroscopy, temperature-programmed desorption (NH3-TPD), scanning electron microscopy, and transmission electron microscopy with high resolutions XRD and BET surface area analysis. These afore mentioned studies confirm that the dealumination process exhibit an increasing the external surface area and improved the total acidity with retaining the structure of mordenite. The catalytic performance was investigated for the of n-hexane, n-pentane and light naphtha isomerization by varying factors such as, temperature, reaction pressure, hydrogen flow, hourly mass feed flow rate and catalyst mass. Among the catalysts, the dealuminated catalyst with SiO2/Al2O3 ratio of 40% exhibited highest conversion Pt–Cl–Al2O3 operate set the lowest temperature on and selectivity. The density functional theory (DFT) calculation implies that the activation free energy for isomerization of n-hexane varies with the position of interacting C–H bond with mordenite (Pt/Mordenite) cluster. Besides, the activation energy for the n-pentane isomerization is lesser than the n-hexane isomerization.

Combined light naphtha isomerization and naphthenic ring opening reaction on modified platinum on chlorinated alumina catalyst

The effect of alumina phases on the catalytic performance of platinum (Pt) on chlorinated alumina catalysts studied in the combined light naphtha isomerization and naphthenic ring opening reaction. The results showed that the type of alumina had a great impact on the catalytic performance of the Pt on chlorinated alumina catalysts. The support prepared by a mixture of eta and gamma alumina with the ratio of 70:30 shows better surface area, acidity and catalytic performance. Extra pre-chlorination of catalysts had a positive effect on the catalytic performance in the butane isomerization reaction. Activities of prepared catalysts tested in a pilot plant with two consecutive fixed bed reactors under different operating conditions. Under the experimental conditions of this study, temperatures greater than 135 °C had a reverse effect on the octane number of the products. It was found that the high LHSV has a negative effect on the strong acidic sites and with returning the LHSV to the initial value, 22DMB/ΣC6 ratio and ring opening reaction rate could not be restored completely.

Effect of the Cr2O3 Promoter on Pt/WO3-ZrO2 Catalysts for n-Heptane Isomerization

Isomerate, the product of a light naphtha Isomerization unit, is a clean, high-octane gasoline blending component, which is free of sulfur content, aromatics, and olefins. However, the isomerization of the long-chain alkanes, such as n-heptane, is pretty difficult. As a result, this process has not been commercialized yet. In recent years, much attention has been paid to Pt/WO3/ZrO2 as an n-heptane isomerization catalyst due to its good thermal stability, strong acidity, simplicity of preparation, reusability and good isomerization activity. In this work, the Pt/WO3/ZrO2 catalyst was modified by various loading of metal Cr to improve the catalytic performance. The effects of WO3 content, Cr metal loading and calcination temperature on the catalyst characters and catalytic activity were studied. It is shown that Cr-Pt/WO3/ZrO2 with the loading of 18 wt% WO3 and 1.0–1.4 wt% Cr, prepared at the calcination temperature of 800 °C, has the highest activity. It was found that the octane number increases by 28 units through the isomerization of light naphtha feedstocks. In addition, the study on the stability of Cr-Pt/WO3/ZrO2 indicates that the catalyst is not deactivated after 500 h of the n-heptane isomerization reaction.

Heat transfer enhancement to decrease the energy consumption of a Light Naphtha Isomerization unit by means of heat exchanger network retrofitting

The Light Naphtha Isomerization (LNI) process increases the quality of gasoline, and the Pinch Design Method (PDM) is a novel method in the field of heat transfer that implements the design of Heat Exchanger Network (HEN) to improve energy efficiency. In this research, the HEN of an LNI unit was retrofitted using PDM to determine the best design to decrease hot and cold utility consumption. Stream selection and data extraction were necessary for PDM, and graphical tools in the form of Composite Curves (CC) and a Grand Composite Curve (GCC) were presented to calculate the minimum and actual hot and cold targets. The base-case results showed minimum hot and cold targets of 37 and 42 MW for ΔTmin = 10 °C, respectively and an energy pocket above the pinch in the interval of between 120 and 180 °C. The pocket enhanced heat recovery because of the large driving forces, decreasing MP steam consumption. Scenarios were suggested for the retrofitting of the LNI unit to enhance heat transfer to decrease energy consumption. In particular, the heat pump intensified heat transfer from the Cooling Water cold utility at 29.5 °C to the MP Steam hot utility at 150 °C.

Platinum Catalysts Supported on Iron-Pillared Sodium- and Calcium-Saturated Montmorillonite in n-Hexane Isomerization

The activity of 0.1%Pt and 0.35%Pt catalysts supported on iron-pillared Na- and Ca-saturated montmorillonite has been tested in the n-hexane isomerization reaction. It has been found that a decrease in the platinum content to 0.1% leads to the formation of high amounts of diisomeric hexanes and heptanes. The activity of the catalysts has been correlated with their physicochemical characteristics determined by the BET, ammonia TPD, electron microscopy, and Mossbauer spectroscopy methods. The high strength of the proposed catalysts, high yields of C6 and C7 di- and tri-isomers from n-hexane in the presence of catalysts with a low Pt content, the use of available and cheap natural materials, and a fairly high n-hexane conversion suggest that these catalysts can be used in the isomerization of low-octane light naphtha to high-octane isomers.