Naphtha Reforming Research Articles

Modeling and Simulation of Prereformed Naphtha and Methane Steam Reforming in a Catalytic Membrane Reactor

Modeling and Simulation of Prereformed Naphtha and Methane Steam Reforming in a Catalytic Membrane Reactor

Simulation and optimization of continuous catalytic reforming: Reducing energy cost and coke formation

Continuous catalytic naphtha reformers are one of the main refinery units producing hydrogen. Reliable and comprehensive modeling of such a complex and integrated refinery unit plays a pivotal role in optimization to increase the efficiency of the process. A reaction network with 26 pseudo components and 58 reactions, considering coke formation and catalyst activity, was proposed to predict the outlet compositions of reactors in more detail. The whole unit, including reaction and purification sections, was simulated to cover all products. NOMAD optimizer, with the mesh adaptive direct search algorithm, is used to minimize energy costs. Non-linear constraints were defined to guarantee the quality of the final products. The optimized decision variables reduced the energy cost by 13.5%, mainly caused by a significant decline in natural gas consumption. The simulation also indicated an increase of 4800 ton/y in reformate production, which the product is rich in aromatics. By contrast, LPG, hydrogen-rich gas, and coke production dropped by nearly 4355, 321, and 127 ton/y, respectively. The coke production decline can significantly increase the catalyst lifetime and decrease the operating cost of the catalyst regeneration unit.

Non-thermal plasma assisted catalytic reforming of naphtha and its model compounds with methane at near ambient conditions

Naphtha reforming processes are widely used for high-octane gasoline production. These processes require high reaction temperature and high pressure of expensive hydrogen. Also, olefins and aromatics are produced for achieving high octane number, which could cause severe environmental issues. Here, we report a novel method of non-thermal plasma assisted catalytic reforming of naphtha at near ambient conditions. Conventionally used hydrogen has been replaced by cheaper methane in this study. Non-thermal plasma could effectively convert methane and naphtha to high-quality fuel at near room temperature and atmospheric pressure. A high-quality fuel with high content of iso-paraffin and low content of olefin and aromatic is produced over optimized Ga/mix-ZSM-5 with non-thermal plasma applied. The produced liquid product has a notably higher iso-paraffin content (increased from 21.5%–40.5%) than raw naphtha while the coke deposition (17.4 %) and the content of olefins (decreased from 13.5%–7.8%) and aromatics (dropped from 18.1%–5.9%) are well controlled. The partial desulfurization of fed coker naphtha by close to 60 % is also successfully achieved. A systematic model compounds study is conducted to investigate the involved mechanism of non-thermal plasma assisted catalytic naphtha reforming and coke deposition. Based on the studies of C6-C16 model compounds (including paraffins, olefins, dienes, cyclo-paraffins, cyclo-olefins and aromatics), a hypothetic reaction mechanism is proposed. A series of control experiments is also carried out to reveal the synergistic effect between non-thermal plasma, catalyst, and methane participation. This research thus pioneers a cost-effective and environmental-friendly route for naphtha reforming at mild conditions.

Study on direct conversion of Naomaohu coal pyrolysis heavy oil to aromatics

The pyrolysis tar from Naomaohu coal was separated by distillation apparatus. Four components of heavy oil above 320°C were analyzed. The result showed the colloid content was 28.84% and the asphaltene content was 35.12%, and both were difficult to convert in hydrogenation. 13C-NMR results showed that the relative molar ratio of aromatic carbon in heavy oil was 71.16%, which indicated that aromatic compounds in heavy fraction were dominant. The heavy fraction was treated by suspension bed and fixed bed cracking. The asphaltene and colloid were almost completely converted. The yield of naphtha with boiling point below 180°C was 66.95%, and the diesel with boiling point higher than 180°C was 17.84%. Oxygen, nitrogen and sulfur contained in heteroatoms were almost completely removed. Catalytic reforming of naphtha was carried out. The results showed that the number of cycloalkanes decreased by 60.23%, and the number of aromatics increased by 65.8%, which indicated that the dehydrogenation and aromatization of cycloalkanes occurred mainly. While the number of n-alkanes decreased by 13.42%, which indicated that the isomerization and cyclization of n-alkanes occurred simultaneously. The catalytic reforming oil contained more benzene, toluene, xylene and ethylbenzene, and the contents were 11.97%, 23.15%, 21.43% and 3.48% respectively. In the direct conversion process of heavy oil from coal pyrolysis, the transmissibility of basic structural units of coal was significantly reflected.

In Situ Generated Organic Peroxides in Oxidative Desulfurization of Naphtha Reformate

In Situ Generated Organic Peroxides in Oxidative Desulfurization of Naphtha Reformate

Modelling Industrial Catalytic Reforming of Lowoctane Gasoline

Naphtha reforming is one of the most important industrial processes in refineries. The products include aromatic hydrocarbons such as benzene, toluene, and xylenes, which are frillier used as high octane additives to gasoline. To increase the efficiency of the process, it is necessary to develop a new method of naphtha reforming. In this work, we have proposed a mathematical model of catalytic refining of low-octane gasoline fracdons into high-octane fractions. The model is based on kinetic equations, established for commercial gasoline reforming in the presence of the platinum-rhenium catalyst on a γ-Al2O3 carrier in the industrial-scale conditions. The equation: describe the dependence of the content of paraffinic, naphthenic, and aromatic hydrocarbon fractions on the process parameters, including volumetric rate and the reaction temperature. The mathematical model had been validated by comparing calculated results with the industrial data obtained from the commercial naphtha reforming production.

Thermodynamically Consistent Kinetic Model for the Naphtha Reforming Process

The work is devoted to development of a kinetic model of the naphtha reforming process based on the previously proposed approach using general rate equations for groups of similar reactions, taking...

Mathematical modeling and optimization of semi-regenerative catalytic reforming of naphtha

Catalytic naphtha reforming is extensively applied in petroleum refineries and petrochemical industries to convert low-octane naphtha into high-octane gasoline. Besides, this process is an important source of hydrogen and aromatics obtained as side products. The bifunctional Pt-catalysts for reforming are deactivated by coke formation during an industrial operation. This results to a reduction in the yield and octane number. In this paper modeling and optimization of a semi-egenerative catalytic reforming of naphtha is carried out considering catalyst deactivation and a complex multicomponent composition of a hydrocarbon mixture. The mathematical model of semi-egenerative catalytic reforming considering coke formation process was proposed. The operating parameters (yield, octane number, activity) for different catalysts were predicted and optimized. It was found that a decrease in the pressure range from 1.5 to 1.2 MPa at the temperature 478–481 °C and feedstock space velocity equal to 1.4–1 h induces an increase in the yield for 1–2 wt.% due to an increase in the aromatization reactions rate and a decrease in the hydrocracking reactions rate depending on the feedstock composition and catalyst type. It is shown that the decrease in pressure is limited by the requirements for the catalyst stability due to the increase in the coke formation rate. The criterion of optimality is the yield, expressed in octanes per tons.

Metal carbide as a potential non noble metal catalyst for naphtha reforming

In petroleum refining, continuous catalytic reforming of heavy naphtha is an important process to produce high value products such as hydrogen and aromatics from the low-value feedstock. Pt-Sn supported on chlorinated alumina is an accepted catalyst over last seven decades. However, use of expensive noble metals and corrosion due to halogen leaching are major issues associated with this catalyst. Such problems can be addressed by replacing the precious Pt metal with equally active and a stable non-precious metal catalytic material over suitable non-chlorinated solid acidic supports. In the present study Fe5C2, WC, Fe2W2C, Mo2C carbide materials have been explored as alternatives to Pt and these materials have been synthesized by solid-state temperature-programmed reaction and supported on different zeolites for imparting acidic function to the catalyst. Screening of these catalyst combinations for heavy naphtha reforming under suitable reaction conditions shows that, Mo2C supported on HY zeolite is found to be an active catalyst compared to any other carbide and zeolite combinations, with product aromatics in the range of 50 wt%, RON of 96, while maintaining reformate yields around 91 wt%.

Catalytic upgrading of heavy naphtha to gasoline: Simultaneous operation of reforming and desulfurization in the absence of hydrogen

Reforming of heavy naphtha in the absence of hydrogen and under more moderate conditions compared with conventional naphtha reforming processes is a very attractive subject. Naphtha reforming in the absence of hydrogen along with desulfurization capability of zeolite catalysts has made the process considerably popular. In order to investigate the effect of operation conditions on the naphtha reforming process using zeolite catalyst in the absence of hydrogen, ZSM-5 catalyst (Si/Al = 50) was successfully synthesized. Three operation parameters including WHSV, temperature and pressure were selected as the main factors to determine the optimal conditions for obtaining maximum octane number, liquid recovery, sulfur conversion and minimum coke deposition on catalyst and benzene content as the responses for the modified Taguchi design of experiments. A model was proposed for each of the responses and the corresponding coefficients were obtained based on the experimental data. The analysis of the results of the experimental design was carried out based on the kinetic models proposed for naphtha reforming process in the absence of hydrogen. The optimum conditions to achieve maximum octane number, liquid recovery, and S conversion and minimum coke deposition on catalyst and benzene content were WHSV =4.02 h−1, temperature = 349.09°C, and pressure = 20 bar. The actual responses obtained using reactor tests under optimal conditions indicated that the proposed model was completely valid.

An investigative study on replacing the conventional furnaces of naphtha reforming with chemical looping combustion for clean hydrogen production

This paper presents a new design for the thermal coupling of the naphtha reforming process with chemical looping combustion (CLC-NR). In this integrated configuration, the chemical looping combustion (CLC) process provides the required heat of the endothermic naphtha reforming process. Hence, intermediate heaters of conventional naphtha reforming (CNR) used to adjust the feed temperature of the reactors were eliminated. Another modification was the replacement of the first conventional furnace of CNR with a novel CLC assisted furnace (CLC-Furnace) to increase the naphtha feed temperature to 777 K. CLC and naphtha reforming processes were considered to occur in fixed-bed reactors in which feed streams can be introduced radially either in inward or outward flow patterns. Results showed that the molar flow rates of aromatics produced in an inward flow pattern are 2kmol/h higher than the outward flow. In order to increase the surface area where the heat transfer takes place, the thermally coupled reactors were divided into some subsections which increased the aromatics and hydrogen production rates by 145kmol/h and 1502kmol/h, respectively. The performance of the novel configuration and conventional radial-flow naphtha reforming (RF-CNR) reactor was also compared demonstrating 10% increase in aromatics production.

Selection of Hydrogen Donors for the Production of Renewable Diesel by in Situ Catalytic Deoxygenation of Palm Oil

Recently, advanced biofuels have gained interest and importance; as a result, the world production of renewable diesel has quadrupled in the last 5 years. Renewable diesel is a type of biodiesel whose functional properties are similar, or even superior, to those of fossil diesel. It also looks more attractive than conventional biodiesel (FAME), as an option for the partial or complete replacement of liquid fossil fuels in the effort to reduce GHG emissions generated in the transport sector of diesel engines. However, when obtained by hydrotreating, the use of gaseous hydrogen makes the process lose sustainability due to its petrochemical origin (at least 90% comes from the reforming of naphtha) and high risk in its safe handling, besides increasing the costs due to its intensive operating conditions (temperature and pressure). A possible solution to this remarkable disadvantage is the generation of hydrogen in situ, which can be carried out by hydrogenation by catalytic transfer, using a donor, usually a solvent that transfers hydrogen. This is an interesting alternative for the hydrogenation of organic compounds, with substantial advantages over processes that use molecular hydrogen, in addition to moderate process conditions and reduction of the intensive energy consumption. In this sense, it is necessary to evaluate potential donors as renewable sources of hydrogen to obtain renewable diesel from palm oil. To carry out the previous analysis, in this study, a multicriteria decision method (MACBETH) is applied, using criteria such as renewable origin, decomposition products, cost, availability and toxicity, which are considered to select the most appropriate family of organic compounds that act as hydrogen donor: alcohols, polyols, aldehydes, ketones, carboxylic acids, condensed aromatic homologs, amines and alkanes. Results show that alcohols, polyols and carboxylic acids are the most suitable organic families for the generation of hydrogen in situ during hydroprocessing. According to sustainability and taking into account the atomic economy, the availability and biorefinery origin, it was found that the most promising compounds to use as donors in each of these families are the ethanol, glycerine and formic acid, which are then evaluated using thermodynamic analysis.

A Detailed Reaction Kinetic Model of Heavy Naphtha Reforming

A detailed reaction kinetic model was developed to describe heavy naphtha reforming reactions. The kinetic model involved 32 lumps and 132 reactions; the lumps were one to 11 carbon atoms n-paraffins, four to 11 carbon atoms iso-paraffins, methylcyclopentene, and six to 11 carbon atoms for naphthenes and aromatics. All computations in the present study were predicted using the particle swarm optimization (PSO) method coded by MATLAB 2015a software. This optimization method was used to estimate the optimum set of kinetic parameters of heavy naphtha reforming reactions. All 150 kinetic and deactivation parameters that were predicted in this work were fine-tuned using PSO. The proposed kinetic model was validated by benchmarking the model results with the data collected over 5 years for a commercial naphtha reforming unit. The mean absolute error for all component compositions within the process was found to be 0.0079. The catalyst deactivation rate was also predicted. It was found that catalyst activity decayed to 58.8% after 1225 operating days.

Editorial: Biographical Memoirs , Volume 68

Editorial: <i>Biographical Memoirs</i> , Volume 68

Non Monotonous Product Distribution Dependence on Pt/γ‐Al2O3−Cl Catalysts Formulation in n‐Heptane Reforming.

AbstractThe synthesis of 19 carefully selected Pt/γ‐Al2O3−Cl formulations was followed by high‐throughput catalytic testing in order to unravel the effect of an active phase formulation change on n‐heptane reforming performances. Pt/γ‐Al2O3−Cl catalysts were prepared with different Pt (0.3–1 %wt) and Cl (0.1–1.4 %wt) contents and using two γ‐Al2O3 supports so that both sites concentrations and sites locations at the crystallite surface vary among the catalyst pool. Catalytic tests were conducted in mild conditions for a comparison of catalysts in kinetic regime. Results show that Pt and Cl concentrations control the competition between hydroisomerisation, hydrogenolysis and hydrocracking pathways. Aromatisation, on the contrary, is poorly affected by formulation changes. Non‐monotonous trends linking Pt/Cl ratio to isomerisation selectivity are found for both γ‐Al2O3 supports. This study provides new insights for the description of bi‐functional transformations in catalytic naphtha reforming.

Modeling and optimization of thermally coupled reactors of naphtha reforming and propane ammoxidation with different feed distributions

In this paper, the thermal coupling of naphtha reforming with propane ammoxidation was simulated using a one-dimensional homogenous model for two processes. By this technique, the required heat for the endothermic naphtha reforming process is provided by the exothermic propane ammoxidation which caused the related furnaces to be removed. The propane ammoxidation takes place in the tube side while the naphtha reforming occurs in the shell side of thermally coupled reactors. Depending on the feed distribution, four configurations including (1) series naphtha-series ammoxidation, (2) series naphtha-parallel ammoxidation, (3) parallel naphtha-parallel ammoxidation, and (4) parallel naphtha-series ammoxidation were investigated to select the best configuration which yields the highest efficiency. The modeling results showed that the first configuration is the best configuration in which produces the aromatics 4 kmol h−1 greater than the conventional naphtha reforming (CNR). Hence the optimization of the first configuration with the genetic algorithm method was done to obtain the optimal value of its key variables. The molar flow rate of aromatics was achieved to 141.9 kmol h−1 at optimized input temperature of naphtha reforming (776.94 K), input temperature of propane ammoxidation (779.9 K) and the number of tubes (395).

Sydney Percy Smith Andrew. 16 May 1926—2 November 2011

Sydney Andrew was an outstanding chemical engineer. His career with ICI was notable, culminating in the rare distinction of appointment as senior research associate. Early work when he was a plant manager led to the development of a systematic procedure for plant maintenance, the forerunner of ‘critical path scheduling’, now widely used for planning complex construction and maintenance projects. Syd did pioneering work on the absorption of gases into liquids where the dissolved gas reacts with the liquid. He helped to develop catalysts for the steam reforming of naphtha, leading to the installation of many plants to provide gas for domestic use; these plants replaced the numerous plants for making town gas from coal. Producing syn-gas from naphtha was beneficial for making ammonia and methanol; several plants were built in India and Japan.

Analysis of combined heat and mass transfer in membrane-assisted thermally coupled reactors containing naphtha reforming and m-xylene hydrodealkylation

In this work, the performance of catalytic naphtha reforming in the thermally coupled membrane reactors has been investigated. It is suggested that the hydrodealkylation of m-xylene be placed in the tube side and the catalytic reforming in the shell side of the proposed reactor. The interior reactor wall has been made of palladium membrane, which permits the hydrogen to penetrate from the shell side with higher partial pressure to the tube with lower partial pressure. Thermal coupling of hydrodealkylation of m-xylene with naphtha reforming, as well as the removal of a part of the hydrogen as a by-product from the reforming side leads to an increase in reformate production. Simulation results indicate that the aromatic production rate in this configuration increases by 16.43% relative to the membrane reactors and by 23.52% relative to the conventional reactors. The effect of parameters including the membrane thickness, inlet temperatures of naphtha and HDA feeds, the molar flow rate of the hydrodealkylation side, the hydrogen to hydrocarbon molar ratio and also, the catalyst deactivation on the performance of the system has been studied. Finally, in order to improve the performance of thermally coupled membrane reactors, the effective parameters in the proposed configuration have been optimized by the genetic algorithm. The yield of aromatic was enhanced by about 14% by this optimization. Also, the conversion of m-xylene in each bed was improved in optimized thermally coupled membrane reactors.

A novel reactor concept for thermal integration of naphtha reforming with propane ammoxidation

In this study, propane ammoxidation as an exothermic process is thermally coupled with the endothermic naphtha reforming process which resulted in the elimination of the naphtha reforming furnaces. Both processes are available in petrochemical plants. Naphtha reforming produces aromatics (BTX, Toluene, Ethylbenzene) as well as hydrogen, while propane ammoxidation reactions on V-Sb-Al oxide catalyst produce acrylonitrile (ACN) as the main product which is a known intermediate for the production of various polymers and polyamides. In addition to energy saving, the aromatics production in the proposed scheme increased by 10% compared to conventional naphtha reforming (CNR). Furthermore, the effect of operating temperature, the number of tubes of the reactors, and the inlet molar flow rate of propane on the hydrogen production and aromatics yield in the naphtha reforming process have been investigated.

Optimization of a novel multifunctional reactor containing m-xylene hydrodealkylation and naphtha reforming

In the present study, efforts have been made to improve the performance of the naphtha reforming process. To this end, the conventional reactors in the naphtha reforming process have been replaced with the new multifunctional reactors. These proposed reactors consist of hydrodealkylation and reforming sides separated by a solid wall and also permeation side that is separated from the reforming side by a palladium membrane wall. The naphtha reforming exchanges the heat with the hydrodealkylation of m-xylene, while this process exchanges the hydrogen gas with the permeation side. This new configuration will lead to an improvement in the production yield of aromatic in the catalytic reforming. According to the simulation results, the production rate of aromatic in this new suggestion increases by about 11% in comparison to the conventional process. The effects of design parameters such as the inlet temperatures of naphtha and hydrodealkylation feeds, the inlet molar flow rate of the hydrodealkylation side and, also the membrane thickness on the system performance have been studied. At the end of the work, the genetic algorithm optimization has been used to determine the best values of varies adjustable parameters in this system.