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Fluidized bed in gravitational shelf dryers: optimization calculation

Artyukhova Nadiia, Krmela Jan, Krmelová Vladimíra, Artyukhov Artem, Gavendová Mária

Bulletin of the Polish Academy of Sciences. Technical Sciences

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2021

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Vol. 69, nr 3

art. no. e137388

EN

The article deals with studying the hydrodynamic characteristics of the fluidized bed in gravitation shelf dryers. The algorithm to calculate hydrodynamic characteristics of the fluidized bed in the dryer’s workspace is described. Every block of the algorithm has a primary hydrodynamic characteristics theoretical model of calculation. Principles of disperse phase motion in various areas in the gravitation shelf dryer are established. The software realization of the author’s mathematic model to calculate disperse phase motion trajectory in a free and constrained regime, disperse phase residence time in the dryers’ workspace, polydisperse systems classification is proposed in the study. Calculations of disperse phase motion hydrodynamic characteristics using the software product ANSYS CFX, based on the author’s mathematic model, are presented in the article. The software product enables automating calculation simultaneously by several optimization criteria and visualizing calculation results in the form of 3D images. The disperse phase flow velocity fields are obtained; principles of a wide fraction of the disperse phase distribution in the workspace of the shelf dryer are fixed. The way to define disperse phase residence time91 in the workspace of the shelf dryer in free (without consideration of cooperation with other particles and dryer’s elements) and con-strained motion regimes is proposed in the research. The calculation results make a base for the optimal choice of the gravitation shelf dryer working chamber sizes.

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Steady state characteristics of a three-phase fluidizedbed bioreactor with partial biomass recirculation

Skoneczny Szymon, Tabiś Bolesław

Chemical and Process Engineering

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2019

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Vol. 40, nr 1

77-–86

EN

The paper presents modeling and simulation results of the operation of a three-phase fluidized bedbioreactorwith partial recirculation of biomass. The proposed quantitative description of the bioreactortakes into account biomass growth on inert carriers, microorganisms decay and interphase biomasstransfer. Stationary characteristicsof the bioreactorand local stability of steady-states were determined.The influence of microbiological growth kinetics on the multiplicity of steady-states was discussed.The relationship between biofilm growth and boundaries of fluidized bed existence was shown

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A Simple Analytical Method for Determining Basic Hydrodynamic Characteristics of Hybrid Fluidized-Bed Air-Lift Apparatae

Tabiś B., Boroń D.

Chemical and Process Engineering

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2017

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Vol. 38, nr 1

121--133

EN

A simple analytical method for determination of basic hydrodynamic characteristics of hybrid fluidized-bed air-lift devices was presented. These devices consist of two parts: a two-phase air-lift part and a two-phase liquid-solid fluidized-bed part. Forced circulation of fluid in the air-lift part is used for fluidization of solid particles in the fluidized-bed part. According to the opinion given in the literature, if such apparatus is used for aerobic microbiological processes, its advantage is lower shear forces acting on the biofilm immobilized on fine-grained material compared with shear forces in three-phase fluidized-bed bioreactors. Another advantage is higher biomass concentration due to its immobilization on fine particles, compared with two-phase airlift bioreactors. A method of calculating gas hold-up in the air-lift part, and gas and liquid velocities in all zones of the analyzed apparatus is presented.