Journal ArticleDOI
Particle suspension and mass transfer rates in agitated vessels
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In this paper, the authors present new information on three aspects of the behaviour of suspended solid particles in agitated tanks, including the minimum rate of stirring required to keep the particles just suspended (JS) against their tendency to settle to the bottom of the tank, and the rate of mass transfer from suspended particles.Abstract:
This paper reviews and presents new information on three aspects of the behaviour of suspended solid particles in agitated tanks. The first is the minimum rate of stirring N required to keep the particles just suspended (JS) against their tendency to settle to the bottom of the tank. The second is the rate of mass transfer from suspended particles. The third is the relation between these two rates, that is, between N JS and the corresponding mass transfer coefficient k LJS . Theoretical and practical aspects of these three problems are discussed here, and it is shown that, starting from basic turbulence theory, one can predict N JS as a function of particle concentration c . The reported constancy of the experimental k LJS when the tank geometry is widely varied follows from the theoretical equations of the present paper.read more
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Journal ArticleDOI
Solid distribution in vessels stirred with multiple impellers
TL;DR: In this article, the authors investigated the solid distribution for solid liquid suspensions under batch and semi-batch conditions in completely closed tanks, where spherical particles of different materials and sizes were used as the solid phase in various liquids.
Journal ArticleDOI
Particle-liquid mass transfer coefficient in two-/three-phase stirred tank reactors
TL;DR: In this article, the effect of system configurations (type of the impeller, D/T, and C/T), operating parameters (impeller speed/power input, particle loading, and gas flow rate), and physical properties (dP, Dm, μ, and Δρ) on kSL have been discussed elaborately.
Journal ArticleDOI
Calculation of critical velocities to maintain solids in suspension in horizontal pipes
TL;DR: In this paper, a simple theoretical justification of the empirical results for the flow velocities required just to suspend solid particles in horizontal pipes is deduced from turbulence theory, which gives a better fit to the empirical data than does the Durand relation.
Journal ArticleDOI
Solids distribution in stirred slurry reactors: influence of some mixer configurations and limits to the applicability of a simple model for predictions
TL;DR: In this paper, the features of solids concentration distribution were investigated in baffled and unbaffled tanks of high aspect ratio, stirred with multiple radial, mixed-flow or axial impellers.
References
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Journal ArticleDOI
Suspending of solid particles in liquid by agitators
TL;DR: In this paper, an investigation of the required stirrer speed and stirrer dimensions for the suspending of solid particles in a low viscosity liquid has been carried out and the results are given in dimensionless form.
Journal ArticleDOI
Mass transfer to particles: Part I. Suspended in agitated tanks
TL;DR: In this article, mass transfer coefficients for particles suspended in agitated, baffled tanks were measured for a given particle size and a given fluid vary with the 0.10 to 0.15 power of the power dissipated per unit volume.
Journal ArticleDOI
Complete suspension of particles in mechanically agitated vessels
TL;DR: In this paper, a new model is proposed to explain the mechanism of complete suspension of solid particles in cylindrical flat-bottomed stirred tanks, which is mainly due to turbulent eddies of a scale of the order of the particles size.
Journal ArticleDOI
Mass transfer coefficients for suspended particles in agitated vessels and bubble columns
TL;DR: In this paper, mass transfer coefficients of suspended particles were measured in agitated vessels and in bubble columns and correlated the surface factor using the Schmidt number as Sh=[2+0.4(edp4/ν3)1/4•Sc1/3]•φc with a standard deviation of 30.8% for the Sherwood number.
Journal ArticleDOI
A generalized theory of sedimentation
A D Maude,R L Whitmore +1 more
TL;DR: In this paper, a theoretical relationship between the concentration and sedimentation velocity of non-flocculated suspensions of particles is derived, and the settling velocity relative to that of a single particle in the suspension is (1 - c)β where β is a function of particle shape, size distribution and Reynolds number and c is the volume of solid per unit volume of suspension.