Fixed Bed Catalytic Reactors. Technological and Fundamental Design Aspects

Froment, Gilbert F.

doi:10.1002/cite.330460903

Cited by 66 publications

(19 citation statements)

References 67 publications

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“…Among others this was also found by Froment (1974). This can be understood if we take into account that mass can not pass through the reactor tube wall, so there is no driving force for mass towards the wall.…”

Section: The Initial Conditions Aresupporting

confidence: 58%

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The choice between cooled tubular reactor models: analysis of the hot spot

Westerink

Koster

Westerterp

1990

Chemical Engineering Science

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Abstract-The applicability of the one-dimensional pseudo-homogeneous model of the cooled tubular reactor is studied. Using the two-dimensional model as the more accurate one we compared both models by studying the influence of the design and operating variables on the conditions in the hot spot of the reactor. The effects were studied on an analytical basis, and a relation is derived that describes the radial temperature profile in the hot spot of the reactor. In the first section we present the model equations and discuss the results obtained from a numerical evaluation. In the second section we compare mean and maximum radial temperatures and reaction rates in case a single exothermic reaction is carried out. We conclude that-for reactors operating in the steady state-in the hot spot the one-dimensional model predicts the proper temperature when it is compared with the average temperature calculated by the twodimensional model, although large differences may arise between maximum and mean radial temperature. A new method is presented to obtain the maximum radial temperature in the hot spot directly from the results of the one-dimensional model. It was found that there can be large differences between the actual average reaction rate and the reaction rate at mean temperature as obtained from the one-dimensional INTBODUflIONIn the literature many studies have been published dealing with the proper design of tubular reactors for exotherrnic reactions. These studies are either based on the prevention of runaway or the preservation of a certain a priori desired selectivity. Well known is the paper by Barkelew (1959), who showed that in a plot of the conversion vs the hot spot temperature two regions can be distinguished. One region-that of the low parametric sensitivity-has the property that a small change in the operating conditions also leads to a small change in the hot spot temperature. In the second region-that of high parametric sensitivity-a small change in operating conditions causes a large increase in the temperature profile along the reactor axis.Westerterp er al. (1984), Westerterp and Overtoom (1985), and Westerlnk and Westerterp (1988) present a series of papers dealing with the design and operation of cooled tubular reactors for reaction systems consisting of two or more exothermic reactions and relate the design and operating parameters to the desired selectivity.Both Barkelew and Westerterp used the pseudo-homogeneous one-dimensional modelto arrive at their results. Morbidelli and Varma (1988, 1989) presented a series of papers in which they study parametric sensitivity in a cooled tubular reactor. They conclude that the reactor becomes sensitive to all the operating conditions and physicochemical parameters simultaneously.'Author to whom correspondence should be addressed. Several investigatorspresented papers that deal with the applicability of the ODM. Froment (1967Froment ( , 1974 studied the difference between the ODM and the pseudo-homogeneous two-dimensional model (TDM).He concluded that fo...

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Section: The Initial Conditions Aresupporting

confidence: 58%

“…Froment (1967Froment ( , 1974 studied the difference between the ODM and the pseudo-homogeneous two-dimensional model (TDM).…”

Section: Several Investigatorsmentioning

confidence: 99%

The choice between cooled tubular reactor models: analysis of the hot spot

Westerink

Koster

Westerterp

1990

Chemical Engineering Science

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“…For the purpose of a performance study of the reactor, one tube of the multitubular FT reactor is modeled, see The modeling of a fixed bed Fischer-Tropsch reactor is presented here in two modes. According to the common classification of fixed bed reactor models [17], one and twodimensional pseudo homogeneous models are used. In pseudo homogeneous model, conditions within the fluid and solid phases (here the bulk gas and catalyst particles) are assumed to be the same.…”

Section: Mathematical Modelingmentioning

confidence: 99%

Fischer-Tropsch Synthesis: Modeling and Performance Study for Fe-HZSM5 Bifunctional Catalyst

Marvast

Sohrabi

Zarrinpashne³

et al. 2005

Chem. Eng. Technol.

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A water-cooled fixed bed Fischer-Tropsch reactor packed with Fe-HZSM5 catalyst has been modeled in two dimensions (radial and axial) using the intrinsic reaction rates previously developed at RIPI. The reactor is used for production of highoctane gasoline from synthesis gas. The Fischer-Tropsch synthesis reactor was a shell and tube type with high pressure boiling water circulating on the shell side. By the use of a two-dimensional model, the effects of some important operating parameters such as cooling temperature, H 2 /CO ratio in syngas and reactor tube diameter on the performance capability of the reactor were investigated. Based on these results, the optimum operating conditions and the tube specification were determined. The model has been used to estimate the optimum operating conditions for the pilot plant to be operated in RIPI.

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“…The performance of a multi-tubular wall-cooled packed bed catalytic reactor is, normally, predicted by the modeling of a single tube, assuming, in a reliable manner, that all tubes behave almost identically [66,67]. Due to this, this work simulates the performance of the MoVTeNbO catalytic formulation during the ODH-Et in a single tube industrial-scale packed bed reactor operating in a non-isothermal and non-adiabatic mode.…”

Section: Industrial-scale Reactor Modelmentioning

confidence: 97%