Catalytic Naphtha Reforming Research Articles

A novel dynamic radial-flow, spherical-bed reactor concept for naphtha reforming in the presence of catalyst deactivation

In this work a novel radial-flow, spherical packed bed reactor (RF-SPBR) for naphtha reforming in the presence of catalyst deactivation, has been proposed. In this reactor configuration, the space between the two concentric spheres is filled by catalyst. The reactants are flowing through the outer surface to the inner sphere. The dynamic simulation of spherical reactors has been studied in the presence of long-term catalyst deactivation. Model equations were solved by the orthogonal collocation method. Further, the performance of the spherical reactors was compared with conventional axial-flow, tubular packed bed reactors (AF-TPBR). The theoretical investigations on the effect of the important parameters, pressure and temperature, on aromatic and hydrogen production and catalyst activity have been investigated. This spherical reactor configuration solves some drawbacks of conventional naphtha reforming reactors such as pressure drop. This work shows how spherical reactor can be useful for catalytic naphtha reforming.

Modeling and Simulation of Moving Bed Reactor for Catalytic Naphtha Reforming

A lumped kinetic model for catalytic naphtha reforming with 27 lumps is developed in order to predict aromatic compositions in more detail. The 8-carbon aromatics are subdivided into ethylbenzene and xylene, and 9-carbon aromatics are subdivided into trimethylbenzene, methylethylbenzene, and propylbenzene, respectively. The simulation of a Universal Oil Products (UOP) commercial continuous reforming unit is carried out to validate the model. The results show that perfect agreement of compositions at the exit of the fourth reactor is obtained between simulated values and reported values and the mass contents of benzene, toluene, ethylbenzene, xylene, trimethylbenzene, methylethylbenzene, and propylbenzene are predicted accurately. The calculated temperature at the exit of each reactor is consistent with the actual value. The composition and temperature profiles are calculated, and the two-dimensional distributions of coke content of catalyst bed are simulated.

Laboratory Studies of Producing Hydrogen and Incremental Oil From Light Oil Reservoirs Using Downhole Gasification

Abstract The idea of gasifying (reforming) a fraction of a light crude oil in the reservoir, was conceived originally by Davidson and Yule(1). This involved "stringing?? a series of downhole gasification (DHG) units along either a horizontal producer well or vertical producer well, or along some other suitable well arrangement. Although catalytic steam reforming of naphtha practiced on a large scale has been extensively researched, such understanding is largely restricted to much lower pressures than those investigated in the present study. We present results obtained using a small, "pilot-scale?? DHG unit, or reforming reactor, operated at up to 100 bar pressure. The feed to this unit was a light naphtha fraction cut from Statfjord crude oil. The effect of pressure, catalyst loading, steam to hydrocarbon ratio and gasifier temperature were investigated. Essentially, the conversion to inert gases, principally hydrogen and carbon dioxide, at high pressure was sufficiently high to make the process technically feasible in depleted light oil reservoirs. Furthermore, the economics of this novel enhanced oil recovery process, which also produces (and stores) hydrogen, appear to be very favourable. However, the experiments, which were conducted under pilot-scale conditions using a single-tube reactor unit, were not of sufficient duration time to test the long-term effects on catalyst activity owing to carbon fouling and sulphur poisoning. These factors (at least carbon deposition) can be controlled as demonstrated in the experiments by adjusting the steam-to-hydrocarbon ratio and the depth of naphtha-cut taken from the crude oil. These aspects of the process are to be further investigated in a Phase 2 project. Introduction Davidson and Yule(1) originally conceived the idea of a self-contained, downhole gasification (DHG) unit as a safer, "greener?? method for transporting oil out of environmentally sensitive areas, such as the Everglades, as gas. Subsequently, the focus was directed towards applying DHG in depleted light oil reservoirs. The inert gases generated by a downhole DHG unit(s) are directed into a gas cap, or used to create a gas cap (Figure 1). This would then allow gravity stabilized displacement (GSGI), WAG, or another assisted gas injection technique, to be implemented for the purpose of improved oil recovery. This is still a high priority, especially in such areas as the North Sea, and the many hundreds of depleted light oil fields in the US, where output continues to fall. The main IOR problem is the availability of a suitable gas to inject into the reservoir, especially offshore. Although the displacement dynamics are likely to be complex because of the hydrogen in the generated gas, it is estimated that valuable incremental oil can be gained using the DHG process.

Catalysis in the Petroleum Naphtha Catalytic Reforming Process

Catalysis in the Petroleum Naphtha Catalytic Reforming Process

Dynamic Modeling and Simulation of Catalytic Naphtha Reforming

In this paper, according to the recent progresses in naphtha reforming technology, dynamic modeling of catalytic naphtha reforming process is studied. The dynamic model is composed of the reforming reaction model, the heat exchanger model, furnace model, which together, are capable to capture the major dynamics that occur in this process system. Kinetic modeling of the reactions of the fixed bed reactors connected in series form the most significant part of the overall simulation effort. MATLAB software in SIMULINK mode is used for dynamic simulation. Hougen-Watson Langmuir-Hinshelwood type reaction rate expressions are used to represent rate of each reaction.The results show models are in fair agreement with the actual operating data.

Lumping procedure for a kinetic model of catalytic naphtha reforming

A lumping procedure is developed for obtaining kinetic and thermodynamic parameters of catalytic naphtha reforming. All kinetic and deactivation parameters are estimated from industrial data and thermodynamic parameters are calculated from derived mathematical expressions. The proposed model contains 17 lumps that include the C6 to C8+ hydrocarbon range and 15 reaction pathways. Hougen-Watson Langmuir-Hinshelwood type reaction rate expressions are used for kinetic simulation of catalytic reactions. The kinetic parameters are benchmarked with several sets of plant data and estimated by the SQP optimization method. After calculation of deactivation and kinetic parameters, plant data are compared with model predictions and only minor deviations between experimental and calculated data are generally observed.

Estimation of the environmental impact of a petrochemical process using coupled LCA and exergy analysis

Reduction of the environmental impact in the oil and gas industry is an ecological and financial issue for process development and design. Currently, the environmental impact of a process is often determined by life cycle assessment (LCA). But exergy analysis has also been proposed to assess process sustainability. To illustrate the potential of coupling LCA and exergy analysis in the petroleum industry, a naphtha catalytic reforming process has been selected and evaluated in terms of climate change, one of the classical environmental impacts used in LCA. LCA and exergy analysis are used together to show how greenhouse gas (GHG) emissions and a thermodynamic indicator ( I p ) related to exergy are modified when the process parameters are varied (feed characteristics, inlet reactor temperature, type of utilities). A positive relationship between GHG emissions and I p has been obtained. It does not depend upon the feed characteristics and can be used for process development without performing a full LCA. The methodology has been extended to take into account natural resources depletion, greenhouse gas emissions and quality of co-products during process development and design for a given product specification. Two catalytic reforming process variants (i.e. processing same inputs and producing same outputs with different internal unit operations arrangement; for this reason, these process variants have the same function) are compared from these previous different points of view. LCA and exergy analysis are shown to be complementary tools.

Development of a Kinetic Model for Catalytic Reforming of Naphtha and Parameter Estimation Using Industrial Plant Data

In the present paper, a semi-empirical kinetic model for catalytic reforming has been developed. In the developed model, the component “lumping” strategy is based on a paraffins, olefins, naphthalenes, and aromatics (PONA) analysis. “Activation energy lumps” are introduced to take into account different values of activation energies within specific reaction classes. The parameters of the model have been estimated by bench marking with industrial data. Simulation results have been found to be in very close agreement with plant data. One of the advantages of the present kinetic model is that it predicts the concentration of hydrogen and light gases very well. Because it is formulated from basic principles, this kinetic model with some modification can be applied to any catalytic reformer.

A membrane catalytic bed concept for naphtha reforming in the presence of catalyst deactivation

In this work, theoretical investigation has been used to evaluate the performance, optimal operating conditions and increasing the aromatic production in a Pd–Ad membrane reactor for catalytic naphtha reforming. A reactor configuration has been used with perm-selective Pd–Ag (23 wt% Ag) wall to hydrogen. The reactants are flowing through the tube side and hydrogen is flowing through the shell side. Hydrogen penetrates from reaction side into the carrier gas due to the hydrogen partial pressure driving force. Hydrogen permeation through membrane leads to shift the reaction towards the product side according to the thermodynamic equilibrium. In this study the theoretical investigation on the effects of pressure, membrane thickness, temperature, H 2/HC ratio and flow rate has been investigated. The changes of aromatic production, H 2/HC mole ratio, temperature, catalyst activity and comparison of equilibrium conversion and reactor model have been shown in this research. Also changing in parameters such as temperature, catalyst activity, components mole fractions and the production or consumption rates of species in industrial case have been demonstrated. This work shows how membrane reactor can be useful for catalytic naphtha reforming by enhancement of aromatic production, increase of catalyst activity and hydrogen separation.

Catalysis in the Petroleum Naphtha Catalytic Reforming Process

Before the US. Patent (1949) by Haensel wherein platinum was used as the active metal component in the industrial catalytic reforming catalysts, molybdenum and /or chromium oxides were used but were suffering from very rapid deactivation by coke even when used under high pressures. Platinum containing catalysts enjoyed very high selectivity via producing high yields of high octane C5 + reformates even at relatively much lower pressures. Improvements were then carried out; some concerned with modifying the metal component, and others concerning modifying the support as well as improving the processing schemes. So many patents were disclosing bimetallic or even polymetallic catalysts containing primarily platinum and/or rhenium or iridium, or their combinations, in addition to tin, zinc, germanium, bismuth, phosphorus, or chlorine, etc. These catalysts acquired advantageous activities, selectivities and long time-on stream with maintaining high yields of high octane motor gasoline.

Definition of a Thermodynamic Parameter to Calculate Carbon Dioxide Emissions in a Catalytic Reforming Process

In the context of global warming, reduction of carbon dioxide emissions in oil and gas processes is an environmental and financial issue for process design and comparison. Environmental impact of a system can be determined by life cycle assessment (LCA). However this method presents limitations. Exergy is a thermodynamic function often chosen to complete LCA as it enables quantifying energetic efficiency of a process and takes into account the relation between the considered process and its environment. The aim of this work is to build a correlation between CO2 emissions and a thermodynamic quantity which depends on exergy. For the process under consideration, this correlation has the following asset: it enables CO2 emissions calculation without performing an LCA, when operating conditions are modified. The process studied here is naphtha catalytic reforming.

Data reconciliation and optimal operation of a Catalytic naphtha reformer

Abstract The naphtha reforming process converts low-octane gasoline blending components to high-octane components for use in high-performance gasoline fuels. The reformer also has an important function as the producer of hydrogen to the refinery hydrotreaters. A process model based on a unit model structure, is used for estimation of the process condition using data reconciliation. Measurements are classified as redundant or non-redundant and the model variables are classified as observable, barely observable or unobservable. The computed uncertainty of the measured and unmeasured variables shows that even if a variable is observable it may have a very large uncertainty and may thereby be practically unobservable. The process condition at 21 data points, sampled from two years of operation, was reconciled and used to optimize the process operation. There are large seasonal variations in the reformer product price and two operational cases are studied. In case 1, the product price is high and throughput is maximized with respect to process and product quality constraints. In case 2, the product price is low and the throughput is minimized with respect to a low constraint on the hydrogen production. Based on the characteristics of the optimal operation, a “self optimizing” control structure is suggested for each of the two operational cases.

Data reconciliation and optimal operation of a catalytic naphtha reformer

The naphtha reforming process converts low-octane gasoline blending components to high-octane components for use in high-performance gasoline fuels. The reformer also has an important function as the producer of hydrogen to the refinery hydrotreaters. A process model based on a unit model structure, is used for estimation of the process condition using data reconciliation. Measurements are classified as redundant or non-redundant and the model variables are classified as observable, barely observable or unobservable. The computed uncertainty of the measured and unmeasured variables shows that even if a variable is observable it may have a very large uncertainty and may thereby be practically unobservable. The process condition at 21 data points, sampled from two years of operation, was reconciled and used to optimize the process operation. There are large seasonal variations in the reformer product price and two operational cases are studied. In case 1, the product price is high and throughput is maximized with respect to process and product quality constraints. In case 2, the product price is low and the throughput is minimized with respect to a low constraint on the hydrogen production. Based on the characteristics of the optimal operation, a “self optimizing” control structure is suggested for each of the two operational cases.

Multiobjective Optimization of the Industrial Naphtha Catalytic Reforming Process

In this article, a multiobjective optimization strategy for an industrial naphtha continuous catalytic reforming process that aims to obtain aromatic products is proposed. The process model is based on a 20-lumped kinetics reaction network and has been proved to be quite effective in terms of industrial application. The primary objectives include maximization of yield of the aromatics and minimization of the yield of heavy aromatics. Four reactor index temperatures, reaction pressure, and hydrogen-to-oil molar ratio are selected as the decision variables. A genetic algorithm, which is proposed by the authors and named as the neighborhood and archived genetic algorithm (NAGA), is applied to solve this multiobjective optimization problem. The relations between each decision variable and the two objectives are also proposed and used for choosing a suitable solution from the obtained Pareto set.

Modeling, Simulation and Optimization of a Whole Industrial Catalytic Naphtha Reforming Process on Aspen Plus Platform

A new 18-lump kinetic model for naphtha catalytic reforming reactions is discussed. By developing this model as a user module, a whole industrial continuous catalytic reforming process is simulated on Aspen plus platform. The technique utilizes the strong databases, complete sets of modules, and flexible simulation tools of the Aspen plus system and retains the characteristics of the proposed kinetic model. The calculated results are in fair agreement with the actual operating data. Based on the model of the whole reforming process, the process is optimized and the optimization results are tested in the actual industrial unit for about two months. The test shows that the process profit increases about 1000yuan·h −1 averagely, which is close to the calculated result.

Hydrogen Production by Catalytic Steam Reforming of Bio-oil, Naphtha and CH4 over C12A7-Mg Catalyst

Hydrogen production by catalytic steam reforming of the bio-oil, naphtha, and CH4 was investigated over a novel metal-doped catalyst of (Ca24Al28O64)4+4O/Mg (C12A7-Mg). The catalytic steam reforming was investigated from 250 to 850C in the fixed-bed continuous flow reactor. For the reforming of bio-oil, the yield of hydrogen of 80% was obtained at 750C, and the maximum carbon conversion is nearly close to 95% under the optimum steam reforming condition. For the reforming of naphtha and CH4, the hydrogen yield and carbon conversion are lower than that of bio-oil at the same temperature. The characteristics of catalyst were also investigated by XPS. The catalyst deactivation was mainly caused by the deposition of carbon in the catalytic steam reforming process.

EXPERT OPTIMAL CONTROL OF CATALYTIC REFORMER USING ANN

ABSTRACT Catalytic naphtha reforming is an important process carried out in refineries for upgrading low-octane naphtha to high-octane gasoline. A reformer can meet many product demands through its wide range of design and flexibility of operation. This work deals with optimization of a catalytic reformer using artificial neural networks (ANN). This optimization requires an accurate process model that is valid over wide range of operating conditions. In this work, a simple kinetic model has been developed. This model gives the temperature and concentration profiles of three important hydrocarbons (naphthenes, paraffins, and aromatics) across the reactors. An optimal control scheme using artificial neural networks has been developed to maximize the aromatics yield, subject to constraints in inlet temperature of the reactors. Two neural networks, one in the forward path and the other in the feedback path, are trained to give set points for temperature control loops of the three reactors. Finally, the results are compared with conventional aromatics yield, and the best performance of ANN based control is validated.

Operability of an Industrial Catalytic Naphtha Reformer in the Presence of Catalyst Deactivation

AbstractBifunctional naphtha reforming catalysts are deactivated by side reactions such as coking, sintering, and poisoning in the course of industrial operation. This results in a reduction of the octane number of the product in a commercial naphtha reforming unit. Catalyst deactivation is compensated for by increasing the operating temperature so that the primary product yields are kept constant during an operating cycle. In the present study, a deactivation model has been developed for industrial catalytic naphtha reformers. The parameters for the deactivation model have been estimated using plant data. The results of the model show that increasing the reactor weighted average inlet temperature (WAIT) can offset the decrease in aromatic yield. Concentration and temperature profiles have been obtained to provide information about the extent of conversion in the individual reactors. Reactor inlet temperature is an important parameter, which can significantly affect reformer performance, the aromatic yield increasing with an increase in temperature.

A study on naphtha catalytic reforming reactor simulation and analysis

A naphtha catalytic reforming unit with four reactors in series is analyzed. A physical model is proposed to describe the catalytic reforming radial flow reactor. Kinetics and thermodynamics equations are selected to describe the naphtha catalytic reforming reactions characteristics based on idealizing the complex naphtha mixture by representing the paraffin, naphthene, and aromatic groups by single compounds. The simulation results based above models agree very well with actual operation unit data.

MOLECULAR MODELING AND OPTIMIZATION FOR CATALYTIC REFORMING

In this paper, molecular modeling and optimization for the naphtha catalytic reforming process is studied. The catalytic reforming process is for producing high octane number gasoline by reforming reactions in three sequencing fixed bed reactors. Feed naphtha coming from an atmospheric distillation unit consisted of molecules from C5 to C10 including paraffin, iso-paraffin, naphthene, and aromatic. The molecular reaction network consisted of paraffin cracking, naphthene side-chain cracking, aromatic side-chain cracking, ring opening, ring closure, paraffin isomerization, dehydrogenation, and hydrogenation. A molecular model for catalytic reforming was built. On the basis of the simulation model, a process optimization was performed for feed temperature and pressure under constraints such as benzene content, aromatic content, and RON (Research Octane Number) limitations. High RON was contrasted to low benzene and aromatic content requirements. By optimizing and controlling the reaction pathway, we can obtain a final product with the highest profit and appropriate benzene and aromatic contents and RON value. This example shows significant benefits from applying molecular modeling to optimization in the process level. Since gasoline production is related to many different processes such as reforming, FCC, isomerization, alkylation, and so on, more benefits can be obtained by applying molecular modeling to plant-wide optimization.