Modular Simulation of Fluidized Bed Reactors

Jafari, Rouzbeh; Sotudeh‐Gharebagh, Rahmat; Mostoufi, Navid

doi:10.1002/ceat.200401908

Cited by 47 publications

(45 citation statements)

References 22 publications

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“…As a matter of fact, since the reactions in this system are slow, a large number of divisions are obtained based on the correlation of Jafari et al [11]. This would result in the closeness of the outcome of the model of Jafari et al [11] (CSTRs + PFRs) with that of the model employed in this work (only CSTRs) due to the fact that a large number of CSTRs behave like a PFR.…”

Section: Reactor Modelingmentioning

confidence: 92%

“…Although the hydrodynamic model of Alizadeh et al [7] is somehow different from that proposed by Jafari et al [11], the number of CSTRs in the present work was obtained from the correlation proposed by Jafari et al [11]. As a matter of fact, since the reactions in this system are slow, a large number of divisions are obtained based on the correlation of Jafari et al [11]. This would result in the closeness of the outcome of the model of Jafari et al [11] (CSTRs + PFRs) with that of the model employed in this work (only CSTRs) due to the fact that a large number of CSTRs behave like a PFR.…”

Section: Reactor Modelingmentioning

confidence: 97%

“…Alizadeh et al [7] considered the fluidized bed reactor for polyethylene production as three CSTRs in series where the number of reactors was a fitting parameter of the model. Jafari et al [11] developed a hydrodynamic model for fluidized bed reactors based on the sequential modular approach which is a combination of the tanks-in-series model for nonideal reactors and the two-phase concept of fluidization. Although the hydrodynamic model of Alizadeh et al [7] is somehow different from that proposed by Jafari et al [11], the number of CSTRs in the present work was obtained from the correlation proposed by Jafari et al [11].…”

Section: Reactor Modelingmentioning

confidence: 99%

“…Jafari et al [11] developed a hydrodynamic model for fluidized bed reactors based on the sequential modular approach which is a combination of the tanks-in-series model for nonideal reactors and the two-phase concept of fluidization. Although the hydrodynamic model of Alizadeh et al [7] is somehow different from that proposed by Jafari et al [11], the number of CSTRs in the present work was obtained from the correlation proposed by Jafari et al [11]. As a matter of fact, since the reactions in this system are slow, a large number of divisions are obtained based on the correlation of Jafari et al [11].…”

Section: Reactor Modelingmentioning

confidence: 99%

See 3 more Smart Citations

Reactor Modeling of Gas‐Phase Polymerization of Ethylene

Kiashemshaki

Mostoufi²,

Sotudeh‐Gharebagh

et al. 2004

Chem Eng & Technol

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A model is developed for evaluating the performance of industrial-scale gas-phase polyethylene production reactors. This model is able to predict the properties of the produced polymer for both linear low-density and high-density polyethylene grades. A pseudo-homogeneous state was assumed in the fluidized bed reactor based on negligible heat and mass transfer resistances between the bubble and emulsion phases. The nonideal flow pattern in the fluidized bed reactor was described by the tanks-in-series model based on the information obtained in the literature. The kinetic model used in this work allows to predict the properties of the produced polymer. The presented model was compared with the actual data in terms of melt index and density and it was shown that there is a good agreement between the actual and calculated properties of the polymer. New correlations were developed to predict the melt index and density of polyethylene based on the operating conditions of the reactor and composition of the reactants in feed.

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Section: Reactor Modelingmentioning

confidence: 92%

Section: Reactor Modelingmentioning

confidence: 97%

Section: Reactor Modelingmentioning

confidence: 99%

Section: Reactor Modelingmentioning

confidence: 99%

See 2 more Smart Citations

Reactor Modeling of Gas‐Phase Polymerization of Ethylene

Kiashemshaki

Mostoufi²,

Sotudeh‐Gharebagh

et al. 2004

Chem Eng & Technol

Self Cite

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“…1, a logical combination of ideal PFR and CSTR reactors is employed in order to create the overall model. The number of sections was initially obtained by considering hydrodynamic and reaction conditions based on the dimensionless J number developed by Jafari et al [17]. This number was proposed for simple reaction systems, which may not be directly applied to the conditions found in the reformer where the reactions are rather complex.…”

Section: Simulation Proceduresmentioning

confidence: 99%

Two‐Phase Sequential Simulation of a Fluidized Bed Reformer

et al. 2008

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A two-phase flow model is adapted in order to predict the performance of a fluidized bed reformer using the sequential modular simulator. Since there are physical and chemical phenomena interacting in the reformer, two sub-models appear to be necessary to describe the overall model. These are the hydrodynamic and reaction sub-models. The hydrodynamic sub-model is based on the dynamic two-phase model and the reaction sub-model is derived from the literature. In the overall model, the bed is divided into several sections. At each section, the flow of the gas is considered as plug flow through the bubble phase and to be perfectly mixed through the emulsion phase. Two sets of experimental data from the literature at different hydrodynamic regimes were used in order to validate the proposed model. A close agreement was observed between the model predictions and the experimental data. The model proposed in this work may be used as a framework for the development of sophisticated models for non-ideal reactors inside process simulators. IntroductionMethane steam reforming on solid catalysts is a well-established commercial process for the production of hydrogen and synthesis gas [1]. A typical structure of industrial reformers is made up of hundreds of fixed-bed tubes, packed with large nickel catalyst particles, and which are heated by an external top-or side-fired furnace [2]. These reformers have several shortcomings including the use of large catalyst particles to avoid excessive pressure drop, which results in their effectiveness factor being rather low [2][3][4]. Moreover, steam reforming of hydrocarbons suffers from carbon formation or coking on the catalyst, which deactivates the catalyst and may lead to a decrease in the efficiency of the reformer [5]. The most severe limitation is the reversibility of the steam reforming reactions, which limits the yield of hydrogen to the thermodynamic equilibrium values [2].Conventional fixed-bed reformers have major disadvantages, e.g., low heat transfer rates, diffusion resistance in the catalyst pores and non-isothermicity. Since the highly endothermic steam methane reforming process is significantly affected by the efficiency of heat input into the reformer, the choice of the reformer is of prime importance. Improved heat transfer, catalyst bed uniformity, and the virtual elimination of diffusion limitations are considered as advantages when using fluidized beds. However, there are some uncertainties associated with the scale up of fluidized bed reformers. In fact, this is the main obstacle in the widespread use of fluidized beds in chemical industries. Therefore, there is a need to develop a structure in order to model and simulate fluidized bed reformers with the aim of using it in a complicated process. Since both hydrodynamic and reactional phenomena coexist in the fluidized bed, one has to consider two sub-models describing these two phenomena in order to achieve a proper simulation model.The hydrodynamics of fluidized beds are the most complex among all gas-solid c...

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Sequential Modeling of Heavy Liquid Fuel Combustion in a Fluidized Bed

et al. 2015

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A sequential model involving hydrodynamic and reaction sub-models is developed to predict the fluidized-bed reactor performance for the combustion of heavy liquid fuels. The hydrodynamic sub-model is based on the modified twophase theory and the reaction sub-model is adopted from the literature. Modeling is performed in a dense bed zone and two types of bubbles, namely distributor bubbles and jet bubbles are considered. Results of the model are presented in terms of combustion efficiency and exhaust emission concentrations. The effect of various factors on these two parameters is investigated. The model is validated with experimental data reported in literature and a close agreement is observed between calculated and experimental values. The proposed model can be applied for simulation of nonideal fluidized-bed combustors using heavy liquid fuels in industrial process simulators.

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Modular Simulation of Fluidized Bed Reactors

Cited by 47 publications

References 22 publications

Reactor Modeling of Gas‐Phase Polymerization of Ethylene

Reactor Modeling of Gas‐Phase Polymerization of Ethylene

Two‐Phase Sequential Simulation of a Fluidized Bed Reformer

Sequential Modeling of Heavy Liquid Fuel Combustion in a Fluidized Bed

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