scholarly journals Diffusion models and scale-up

2005 ◽  
Vol 9 (1) ◽  
pp. 43-72 ◽  
Author(s):  
Christo Boyadjiev
Keyword(s):  
Mass Transfer ◽  
Parameter Identification ◽  
Fluidized Bed ◽  
Scale Up ◽  
Catalytic Reactions ◽  
Fluidized Bed Reactors ◽  
Hierarchical Approach ◽  
Model Parameter ◽  
Transfer Processes ◽  
Three Phase

A model for transfer processes in column apparatuses has been done. The model may be modified for different apparatuses as columns with (or without) packet bed, two (or three) phase airlift reactors and fluidized bed reactors. The mass transfer is result of different volume reactions as a chemical, photochemical, biochemical or catalytic, reactions, or interphase. mass transfer. The using of the average velocities and concentration permit to solve the scale-up problems. A hierarchical approach for model parameter identification has been proposed.

Mass transfer between solid particles and liquid in a three phase fluidized bed

1987 ◽  
Vol 65 (2) ◽  
pp. 228-236 ◽  
Author(s):  
A. Prakash ◽  
C. L. Briens ◽  
M. A. Bergougnou
Keyword(s):  
Mass Transfer ◽  
Fluidized Bed ◽  
Solid Particles ◽  
Three Phase

Wall-to-Bed Mass Transfer in a Three-Phase Fluidized Bed with Twisted Tape as Internal

2014 ◽  
Vol 95 (1) ◽  
pp. 49-56 ◽  
Author(s):  
B. S. Subramanyam ◽  
M. S. N. Murty ◽  
B. S. Babu ◽  
K. V. Ramesh
Keyword(s):  
Mass Transfer ◽  
Fluidized Bed ◽  
Twisted Tape ◽  
Three Phase

scholarly journals Electro Winning from Dilute Solutions at Enhanced Rates using Three-Phase Flow Reactor

2020 ◽  
Vol 9 (4) ◽  
pp. 1740-1745
Keyword(s):  
Mass Transfer ◽  
Transfer Coefficient ◽  
Mass Transfer Coefficient ◽  
Fluidized Bed ◽  
Flow Reactor ◽  
Liquid Velocity ◽  
Particle Diameter ◽  
Limiting Current ◽  
Process Equipment ◽  
Three Phase

Enhancement of mass transfer coefficient is highly desirable for economic design of process equipment. The present study is essentially carried out to know the effect of flow variables such as gas and liquid velocities and geometric parameters of the internal on mass transfer coefficients in a three phase fluidized bed. The mass transfer coefficient data were obtained using a string of cones internal in a three-phase fluidized bed electrochemical reactor. The flow system investigated was nitrogen, a fluid electrolyte and spherical glass beads as gas, liquid and solid phases respectively. Limiting current technique was employed to obtain mass transfer data. The internal comprises of a string of cones arranged concentrically on a central rod which is placed coaxially in a three phase fluidized bed. The presence of internal in three phase fluidized beds augmented the mass transfer coefficient significantly. In the present investigation it was found that the effect of gas velocity, liquid velocity, rod diameter and cone diameter was only marginal. However, the influence of pitch, half apex angle of cone and particle diameter was found to be significant. Correlations were developed based on least squares regression analysis for the prediction of mass transfer coefficient in terms of pertinent variables

Development of a Continuous Fluidized Bed Reactor for Thermochemical Energy Storage Application

2019 ◽  
Vol 141 (7) ◽  
Author(s):  
Manuel Wuerth ◽  
Moritz Becker ◽  
Peter Ostermeier ◽  
Stephan Gleis ◽  
Hartmut Spliethoff
Keyword(s):  
Energy Storage ◽  
Fluidized Bed ◽  
State Of The Art ◽  
Scale Up ◽  
Fixed Bed ◽  
Fluidized Bed Reactor ◽  
Fluidized Bed Reactors ◽  
Heat Of Reaction ◽  
Reaction Systems

Thermochemical energy storage (TCES) represents one of the most promising energy storage technologies, currently investigated. It uses the heat of reaction of reversible reaction systems and stands out due to the high energy density of its storage materials combined with the possibility of long-term storage with little to no heat losses. Gas–solid reactions, in particular the reaction systems CaCO3/CaO, CaO/Ca(OH)2 and MgO/Mg(OH)2 are of key interest in current research. Until now, fixed bed reactors are the state of the art for TCES systems. However, fluidized bed reactors offer significant advantages for scale-up of the system: the improved heat and mass transfer allows for higher charging/discharging power, whereas the favorable, continuous operation mode enables a decoupling of storage power and capacity. Even though gas–solid fluidized beds are being deployed for wide range of industrial operations, the fluidization of cohesive materials, such as the aforementioned metal oxides/hydroxides, still represents a sparsely investigated field. The consequent lack of knowledge of physical, chemical, and technical parameters of the processes on hand is currently a hindering aspect for a proper design and scale-up of fluidized bed reactors for MW applications of TCES. Therefore, the experimental research at Technical University of Munich (TUM) focuses on a comprehensive approach to address this problem. Preliminary experimental work has been carried out on a fixed bed reactor to cover the topic of chemical cycle stability of storage materials. In order to investigate the fluidization behavior of the bulk material, a fluidized bed cold model containing a heat flux probe and operating at atmospheric conditions has been deployed. The experimental results have identified the heat input and output as the most influential aspect for both the operation and a possible scale-up of such a TCES system. The decisive parameter for the heat input and output is the heat transfer coefficient between immersed heat exchangers and the fluidized bed. This coefficient strongly depends on the quality of fluidization, which in turn is directly related to the geometry of the gas distributor plate. At TUM, a state-of-the-art pilot fluidized bed reactor is being commissioned to further investigate the aforementioned aspects. This reactor possesses an overall volume of 100 L with the expanded bed volume taking up 30 L. Two radiation furnaces (64 kW) are used to heat the reactor. The heat of reaction of the exothermal hydration reaction is removed by water, evaporating in a cooling coil, immersed in the fluidized bed. Fluidization is being achieved with a mixture of steam and nitrogen at operating temperatures of up to 700 °C and operating pressures between −1 and 6 bar(g). The particle size is in the range of d50 = 20 μm. While initial experiments on this reactor focus on optimal operating and material parameters, the long-term goal is to establish correlations for model design and scale-up purposes.

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