Topic
Mass transfer coefficient
About: Mass transfer coefficient is a research topic. Over the lifetime, 7827 publications have been published within this topic receiving 168354 citations.
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TL;DR: In this article, the overall gas hold-up, the volumetric mass transfer coefficient, the liquid side mass transfer coefficients, and the bubble size were investigated in two bubble columns and a non-standard vessel equipped with various dual-impeller combinations.
Abstract: The overall gas hold-up e g , the volumetric mass transfer coefficient k 1 a , the liquid side mass transfer coefficient k 1 , the volumetric interfacial area a , the bubble size d bs and bubble distribution have been characterised in two bubble columns and a non-standard vessel equipped with various dual-impeller combinations. In the bubble columns, the effects of gas flow rate, sparger type and column diameter were investigated. In the dual-impeller stirred reactor, the effects of rotational speed, gas flow rate, impeller type and diameter were studied. The performances of the two reactors are compared here, and some relationships are proposed and compared with existing correlations.
323 citations
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TL;DR: In this paper, a two-scale continuum model is developed to describe transport and reaction mechanisms in reactive dissolution of a porous medium, and used to study wormhole formation during acid stimulation of carbonate cores.
Abstract: A two-scale continuum model is developed to describe transport and reaction mechanisms in reactive dissolution of a porous medium, and used to study wormhole formation during acid stimulation of carbonate cores. The model accounts for pore level physics by coupling local pore-scale phenomena to macroscopic variables (Darcy velocity, pressure and reactant cup-mixing concentration) through structure-property relationships (permeability-porosity, average pore size-porosity, and so on), and the dependence of mass transfer and dispersion coefficients on evolving pore scale variables (average pore size and local Reynolds and Schmidt numbers). The gradients in concentration at the pore level caused by flow, species diffusion and chemical reaction are described using two concentration variables and a local mass-transfer coefficient. Numerical simulations of the model on a two-dimensional (2-D) domain show that the model captures the different types of dissolution patterns observed in the experiments. A qualitative criterion for wormhole formation is developed and it is given by Λ ∼ O(1), where Λ = . Here, keff is the effective volumetric dissolution rate constant, DeT is the transverse dispersion coefficient, and uo is the injection velocity. The model is used to examine the influence of the level of dispersion, the heterogeneities present in the core, reaction kinetics and mass transfer on wormhole formation. The model predictions are favorably compared to laboratory data. © 2005 American Institute of Chemical Engineers AIChE J, 2005
317 citations
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TL;DR: In this article, the influence of the capillary diameter, unit cell length and gas hold-up on measured kLa and kSa coefficients was correlated by simple correlation, which showed that in both cases the mass transport is mostly determined by the liquid slug length and velocity.
310 citations
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TL;DR: In this article, a simple correlation for the over-all mass transfer coefficient is presented, which holds with a probable error of 20% for both directions of transfer with either phase dispersed, and is useful for the extrapolation of performance from system to system in a given piece of equipment.
Abstract: Mass and heat transfer rates in extraction are studied theoretically and experimentally for the practical range of the variables involved. For the particular but typical case of liquid drops moving through another liquid a simple correlation for the over-all mass transfer coefficient is presented, which holds with a probable error of 20%.
Included are systems in which the rate is limited by either coefficient, as well as systems in which both coefficients are significant. The correlation, valid for both directions of transfer with either phase dispersed, is useful for the extrapolation of performance from system to system in a given piece of equipment. Also, together with correlations for transfer area and effective driving force, it is part of the information needed for design.
297 citations
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TL;DR: In this article, the effect of pH, temperature, initial absorbate concentration, particle size of the adsorbent and solid to liquid ratio on the kinetics of adsorption was delineated.
295 citations