scholarly journals The Experimental Study of the Kinetics of the Cyclic Adsorption Process of Air Enrichment with Oxygen

2021 ◽  
Vol 27 (3) ◽  
pp. 387-400
Author(s):  
E. I. Akulinin ◽  
D. S. Dvoretsky ◽  
S. I. Dvoretsky
Keyword(s):  
Mass Transfer ◽  
Adsorption Process ◽  
Numerical Study ◽  
Air Separation ◽  
Diffusion Resistance ◽  
Kinetic Regime ◽  
Atmospheric Air ◽  
Mass Conductivity ◽  
Cyclic Adsorption ◽  
Kinetics Of

For mass transfer cyclic processes in the “adsorptive - porous adsorbent” system when air is enriched with oxygen by the method of short-cycle heatless adsorption, a new method has been implemented for determining the coefficients of mass transfer and mass conductivity of processes in systems with a solid phase from kinetic curves. It has been experimentally proved that during the adsorption separation of atmospheric air, the rate of cyclic “adsorption - desorption” processes can be limited by both internal and external diffusion resistance. The mass conductivity coefficients are determined depending on the mass content of the distributed adsorptive (O2, N2) by a method that does not require the implementation of the intradiffusion kinetic regime. The analysis of the kinetics of the process of air enrichment with oxygen is carried out; the coefficients of mass transfer and mass conductivity, which can be used in kinetic calculations and numerical study of the properties and modes of the cyclic adsorption process of atmospheric air separation and oxygen concentration, are determined.

scholarly journals Numerical study of the dynamics and optimization of the modes of air adsorption separation and oxygen concentration

2019 ◽  
Vol 81 (1) ◽  
pp. 310-317
Author(s):  
E. I. Akulinin ◽  
O. O. Golubyatnikov ◽  
D. S. Dvoretsky ◽  
S. I. Dvoretsky
Keyword(s):  
Oxygen Concentration ◽  
Gas Flow ◽  
Numerical Study ◽  
Air Separation ◽  
Zeolite 13X ◽  
Wide Range ◽  
Cyclic Processes ◽  
Pressure Swing ◽  
Cyclic Adsorption ◽  
Adsorption Desorption

Numerical researches of influence of temperature, composition and pressure changes of the initial gas mixture on the purity, recovery and capacity of the pressure swing adsorption (PSA) unit was made. Air separation dynamics was researches in a wide range of control (pressure at the compressor outlet, the duration of the adsorption – desorption cycle, backflow coefficient, programs of control valves opening degree in time) variables. It was found that the change of regime parameters and the inflow on has a significant impact on the purity and recovery of oxygen. Also was founded that the range of the duration of the adsorption stage and the compressor outlet pressure values should be limited to the intervals of 39-43 s and 2.7–2.8?105 Pa, respectively. The steady-state of the PSA unit mode output time was amount 20-30 cycles of "adsorption-desorption". Formulated and solved the optimization tasks of regime parameters of air separation cyclic processes by criterion of maximum oxygen recovery in 2-bed PSA unit with granular adsorbent zeolite 13X; the optimal values of the control parameters for differential environmental conditions (when the product oxygen concentration not less than 45% vol. and the PSA unit capacity ~2 l/min) are determined. It is shown that the implementation of the optimal of the inlet and discharge valves opening degree changes program in PSA unit allows to provide the set values of the gas flow rate in the "frontal" layer of the adsorbent, in which there is no abrasion of the adsorbent in the cyclic adsorption–desorption processes

scholarly journals Mass transfer in the bath reactor of the adsorption process of 1,2-dichloropropane from aqueous solution onto the activated carbon

2007 ◽  
Vol 9 (2) ◽  
pp. 30-33
Author(s):  
Robert Pełech
Keyword(s):  
Aqueous Solution ◽  
Mass Transfer ◽  
Activated Carbon ◽  
Rate Constant ◽  
Adsorption Process ◽  
Particle Diameter ◽  
Mixing Conditions ◽  
Pseudo Second Order ◽  
Kinetics Of ◽  
Order Rate Equation

Mass transfer in the bath reactor of the adsorption process of 1,2-dichloropropane from aqueous solution onto the activated carbon A pseudo-second order rate equation describing the kinetics of the adsorption of 1,2-dichloropropane from aqueous solution onto the activated carbon at different initial concentrations, adsorbent dose, temperature, particle diameter and the rate of stirring have been developed. The rate constant was calculated. The rate constant correlation in a good mixing conditions was described as a function of the temperature.

Improved ODE integrator and mass transfer approach for simulating a cyclic adsorption process

2003 ◽  
Vol 27 (6) ◽  
pp. 883-899 ◽  
Author(s):  
Richard S. Todd ◽  
Guido Buzzi Ferraris ◽  
Davide Manca ◽  
Paul A. Webley
Keyword(s):  
Mass Transfer ◽  
Adsorption Process ◽  
Cyclic Adsorption

Numerical Study of the Combined Free-Forced Convection and Mass Transfer Flow Past a Vertical Porous Plate in a Porous Medium with Heat Generation and Thermal Diffusion

2006 ◽  
Vol 11 (4) ◽  
pp. 331-343 ◽  
Author(s):  
M. S. Alam ◽  
M. M. Rahman ◽  
M. A. Samad
Keyword(s):  
Mass Transfer ◽  
Flow Field ◽  
Differential Equations ◽  
Forced Convection ◽  
Heat Generation ◽  
Numerical Study ◽  
Porous Plate ◽  
Integration Scheme ◽  
Suction Parameter ◽  
Transfer Flow

The problem of combined free-forced convection and mass transfer flow over a vertical porous flat plate, in presence of heat generation and thermaldiffusion, is studied numerically. The non-linear partial differential equations and their boundary conditions, describing the problem under consideration, are transformed into a system of ordinary differential equations by using usual similarity transformations. This system is solved numerically by applying Nachtsheim-Swigert shooting iteration technique together with Runge-Kutta sixth order integration scheme. The effects of suction parameter, heat generation parameter and Soret number are examined on the flow field of a hydrogen-air mixture as a non-chemical reacting fluid pair. The analysis of the obtained results showed that the flow field is significantly influenced by these parameters.

scholarly journals Numerical Study of a Cooling System Using Phase Change of a Refrigerant in a Thermosyphon

Energies ◽  
2021 ◽  
Vol 14 (12) ◽  
pp. 3634
Author(s):  
Grzegorz Czerwiński ◽  
Jerzy Wołoszyn
Keyword(s):  
Mass Transfer ◽  
Phase Change ◽  
Heat Dissipation ◽  
Cooling System ◽  
Numerical Study ◽  
Relaxation Parameter ◽  
Phase Changes ◽  
Transfer Time ◽  
Two Phase ◽  
Time Relaxation

With the increasing trend toward the miniaturization of electronic devices, the issue of heat dissipation becomes essential. The use of phase changes in a two-phase closed thermosyphon (TPCT) enables a significant reduction in the heat generated even at high temperatures. In this paper, we propose a modification of the evaporation–condensation model implemented in ANSYS Fluent. The modification was to manipulate the value of the mass transfer time relaxation parameter for evaporation and condensation. The developed model in the form of a UDF script allowed the introduction of additional source equations, and the obtained solution is compared with the results available in the literature. The variable value of the mass transfer time relaxation parameter during condensation rc depending on the density of the liquid and vapour phase was taken into account in the calculations. However, compared to previous numerical studies, more accurate modelling of the phase change phenomenon of the medium in the thermosyphon was possible by adopting a mass transfer time relaxation parameter during evaporation re = 1. The assumption of ten-fold higher values resulted in overestimated temperature values in all sections of the thermosyphon. Hence, the coefficient re should be selected individually depending on the case under study. A too large value may cause difficulties in obtaining the convergence of solutions, which, in the case of numerical grids with many elements (especially three-dimensional), significantly increases the computation time.

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