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Computational analysis of an instantaneous irreversible reaction in a T-microreactor

Bothe, D. and Lojewski, A. and Warnecke, H.-J. (2010):
Computational analysis of an instantaneous irreversible reaction in a T-microreactor.
In: AIChE J., pp. 1406-1415, 56, (6), [Article]

Abstract

We extend and apply a method for the numerical computation of convective and diffusive mixing in liquid systems with very fast irreversible chemical reaction to the case of unequal diffusivities. This approach circumvents the solution of stiff differential equations and, hence, facilitates the direct numerical simulation of flow based reactive mixing with instantaneous reactions like neutralizations or more general ionic reactions. The method is validated by means of the neutralization reaction between hydrochloric acid and sodium hydroxide. This reaction is studied in a T-shaped micromixer and compared with existing experimental data. Due to their large are-to-volume ratio, microreactors provide enhanced mass and energy transport. Hence, they are well suited for fast chemical reactions which are seriously affected by the slow diffusive transport in aqueous media. The simulation results agree very well with given data from laser induced fluorescence measurements. Numerical computations for different reactor dimensions reveal the fact that, in a dimensionless setting, the obtained conversion is independent of the reactor size, if the flow conditions are the same. This corresponds to an increase of space-time-yield proportional to the square of the inverse scale factor.

Item Type: Article
Erschienen: 2010
Creators: Bothe, D. and Lojewski, A. and Warnecke, H.-J.
Title: Computational analysis of an instantaneous irreversible reaction in a T-microreactor
Language: English
Abstract:

We extend and apply a method for the numerical computation of convective and diffusive mixing in liquid systems with very fast irreversible chemical reaction to the case of unequal diffusivities. This approach circumvents the solution of stiff differential equations and, hence, facilitates the direct numerical simulation of flow based reactive mixing with instantaneous reactions like neutralizations or more general ionic reactions. The method is validated by means of the neutralization reaction between hydrochloric acid and sodium hydroxide. This reaction is studied in a T-shaped micromixer and compared with existing experimental data. Due to their large are-to-volume ratio, microreactors provide enhanced mass and energy transport. Hence, they are well suited for fast chemical reactions which are seriously affected by the slow diffusive transport in aqueous media. The simulation results agree very well with given data from laser induced fluorescence measurements. Numerical computations for different reactor dimensions reveal the fact that, in a dimensionless setting, the obtained conversion is independent of the reactor size, if the flow conditions are the same. This corresponds to an increase of space-time-yield proportional to the square of the inverse scale factor.

Journal or Publication Title: AIChE J.
Volume: 56
Number: 6
Uncontrolled Keywords: Quasi-instantaneous chemical reaction, neutralization, reaction-convection-diffusion equation, T-shaped microreactor, 3D fully resolved numerical simulations
Divisions: Exzellenzinitiative > Clusters of Excellence > Center of Smart Interfaces (CSI)
04 Department of Mathematics > Mathematical Modelling and Analysis
UNSPECIFIED
Zentrale Einrichtungen
04 Department of Mathematics
Exzellenzinitiative
Exzellenzinitiative > Clusters of Excellence
Date Deposited: 05 Apr 2011 12:32
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