Steady state multiplicity behavior of an isothermal axial dispersion fixed-bed reactor with nonuniformly active catalyst

Abstract A NOx adsorption kinetic model including NO oxidation and adsorption was developed. The NOx and O2 adsorption experimental data from a fixed bed were found to be fitted well to the Freundlich type isotherm. An axial dispersion adsorption model was then developed to simulate the breakthrough curve for NOx adsorption in the fixed bed. The model parameters including mass transfer coefficient and axial dispersion coefficient were fitted from the NOx breakthrough curves measured in a fixed bed. This model can be used for design and scale-up of fixed bed NOx adsorption columns. It can also be extended for the modeling of NOx adsorption in the annulus region of the circulating fluidized bed reactor for catalytic reduction of NOx.

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Modeling of chemical reactors—XXVIII. Steady state operation of tubular adiabatic fixed bed reactor with piston flow and external heat and mass transfer

Chemical Engineering Science ◽

10.1016/0009-2509(74)80010-2 ◽

1974 ◽

Vol 29 (12) ◽

pp. 2333-2338 ◽

Cited By ~ 6

Author(s):

J. Votruba ◽

M. Kubíček ◽

V. Hlaváček

Keyword(s):

Mass Transfer ◽

Steady State ◽

Heat And Mass Transfer ◽

Fixed Bed ◽

External Heat ◽

Fixed Bed Reactor ◽

Chemical Reactors ◽

Steady State Operation ◽

Piston Flow

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Evaluation of stability of a catalytic fixed-bed reactor from a steady-state model

Chemical Engineering Science ◽

10.1016/0009-2509(93)81024-p ◽

1993 ◽

Vol 48 (21) ◽

pp. 3677-3681 ◽

Cited By ~ 1

Author(s):

Venkata R. Khandavalli ◽

V.Dharma Rao ◽

M.V. Ramakanth ◽

Kirankumar V. Athota

Keyword(s):

Steady State ◽

Fixed Bed ◽

State Model ◽

Fixed Bed Reactor ◽

Steady State Model

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Dynamic Simulation of Adiabatic Catalytic Fixed-Bed Tubular Reactors: A Simple Approximate Modeling Approach

ASEAN Journal of Chemical Engineering ◽

10.22146/ajche.49713 ◽

2014 ◽

Vol 14 (1) ◽

pp. 25

Author(s):

Wiwut Tanthapanichakoon ◽

Shinichi Koda ◽

Burin Khemthong

Keyword(s):

Dynamic Model ◽

Dynamic Behavior ◽

Dynamic Simulation ◽

Flow Rate ◽

Fixed Bed ◽

Axial Dispersion ◽

Fixed Bed Reactor ◽

Inlet Temperature ◽

Acetylene Hydrogenation ◽

Tubular Reactors

Fixed-bed tubular reactors are used widely in chemical process industries, for example, selective hydrogenation of acetylene to ethylene in a naphtha cracking plant. A dynamic model is required when the effect of large fluctuations with time in influent stream (temperature, pressure, flow rate, and/or composition) on the reactor performance is to be investigated or automatically controlled. To predict approximate dynamic behavior of adiabatic selective acetylene hydrogenation reactors, we proposed a simple 1-dimensional model based on residence time distribution (RTD) effect to represent the cases of plug flow without/with axial dispersion. By modeling the nonideal flow regimes as a number of CSTRs (completely stirred tank reactors) in series to give not only equivalent RTD effect but also theoretically the same dynamic behavior in the case of isothermal first-order reactions, the obtained simple dynamic model consists of a set of nonlinear ODEs (ordinary differential equations), which can simultaneously be integrated using Excel VBA (Visual BASIC Applications) and 4th-order Runge-Kutta algorithm. The effects of reactor inlet temperature, axial dispersion, and flow rate deviation on the dynamic behavior of the system were investigated. In addition, comparison of the simulated effects of flow rate deviation was made between two industrial-size reactors.Keywords: Dynamic simulation, 1-D model, Adiabatic reactor, Acetylene hydrogenation, Fixed-bed reactor, Axial dispersion effect

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Optimal catalyst activity distribution in fixed-bed reactor with catalyst deactivation

Collection of Czechoslovak Chemical Communications ◽

10.1135/cccc19890375 ◽

1989 ◽

Vol 54 (2) ◽

pp. 375-387 ◽

Cited By ~ 2

Author(s):

Jozef Markoš ◽

Alena Brunovská

Keyword(s):

Catalyst Deactivation ◽

Active Catalyst ◽

Catalyst Activity ◽

Fixed Bed ◽

Fixed Bed Reactor ◽

Catalytic Reactor ◽

Reactor Performance ◽

Thiele Modulus ◽

Activity Distribution ◽

Parameter Ratio

In this paper the influence of the active catalyst location in a pellet on fixed-bed catalytic reactor performance is described. The optimal activity distribution as a function of an economic parameter (ratio of product and catalyst costs), Thiele modulus and Damkohler number is estimated.

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Analysis of multicomponent reversible reactions in an isothermal fixed bed reactor with axial dispersion

The Chemical Engineering Journal ◽

10.1016/0300-9467(84)80004-0 ◽

1984 ◽

Vol 29 (1) ◽

pp. 29-40 ◽

Cited By ~ 1

Author(s):

Ha D. Do ◽

D.D. Do

Keyword(s):

Fixed Bed ◽

Axial Dispersion ◽

Fixed Bed Reactor ◽

Reversible Reactions

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Steady State Model for Heat Transfer in a Packed Bed Reactor of Elliptic Cylindrical Shape

International Journal of Chemical Reactor Engineering ◽

10.2202/1542-6580.1771 ◽

2008 ◽

Vol 6 (1) ◽

Cited By ~ 2

Author(s):

Laércio G. Oliveira ◽

Ramdayal Swarnakar ◽

Antonio G. B. de Lima

Keyword(s):

Heat Transfer ◽

Steady State ◽

Fixed Bed ◽

Packed Bed ◽

Numerical Results ◽

Packed Bed Reactor ◽

Fixed Bed Reactor ◽

Dimensionless Temperature ◽

Cylindrical Shape ◽

Temperature Profiles

The fixed-bed reactors of circular cylindrical geometry with heated or cooled walls are frequently used to carry out heterogeneous reactions of solid-gas type in engineering applications. The design of a fixed bed reactor requires an extensive knowledge of heat transfer characteristics within the packed bed. In this sense, this work presents a three-dimensional mathematical model to predict the heat transfer inside a fixed bed elliptical cylinder heat exchanger. The model considers uniform velocity and temperature profiles of the fluid phase at the entrance of the reactor, and constant thermo-physical properties. The surface of the equipment convective boundary condition is assumed to be constant. The energy equation, written in the elliptical cylindrical coordinates, was discretized using a finite-volume method considering a fully implicit formulation, and WUDS interpolation scheme. Numerical results of the dimensionless temperature profiles inside the packed bed reactor at a steady state are presented and temperature distribution is interpreted. To validate the model, numerical results obtained for the circular cylinder are compared with analytical results from literature and a good agreement was obtained.

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