Volume 14, no. 2Pages 39 - 51

Numerical Research to Determine the Dominant Mechanism of Mass and Heat Transfer in Pressure Swing Adsorption Processes

O.O. Golubyatnikov, E.I. Akulinin, S.I. Dvoretsky
The existing mathematical models of pressure swing adsorption (PSA) apply various assumptions regarding the mass and heat transfer mechanisms in the “gas mixtureadsorbent” system. An increase in the number of assumptions leads to a simplification of the model, a decrease in the calculation time of one iteration in the model and, at the same time, a decrease in its accuracy. The simplification of the model is especially important in PSA processes, since the calculation of the model is carried out before the cyclic steady state and takes tens and even hundreds of cycles (iterations). Ensuring high accuracy of the PSA model and its minimum complexity is a contradictory requirement; therefore it is important to reasonably consider only those transfer mechanisms that are dominant in the model. The paper proposes a mathematical model of the PSA process, which takes into account the thermal effects of sorption, external and internal diffusion mechanisms of adsorptive transfer. A numerical research was carried out to determine the dominant transfer mechanism, and recommendations were proposed for using the preferred PSA model in terms of its accuracy and calculation time (for the processes of air oxygen enrichment and synthesis gas separation). It was found that to calculate PSA oxygen units with a capacity of less than 4 l/min at NTP, it is advisable to use an isothermal model, which saves at least 24,3% of the calculation time with a loss of accuracy of no more than 0,084 vol%. To calculate PSA hydrogen units, the use of an isothermal model is impractical even at the lowest productivity of 50 l/min at NTP. When the diameter of the adsorbent particles is less than 2 mm, it is advisable to use an external diffusion model, which saves at least 54,2% of the calculation time for oxygen units and at least 47,1% of the calculation time for hydrogen units with a slight loss of accuracy. At a gas flow velocity of more than 0,05 m/s, the model can ignore the diffusion in the gas. The research results can be used to calculate various PSA processes for separation of gas mixtures: rPSA, ultra rPSA, VSA, VPSA, and related processes.
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Keywords
pressure swing adsorption; mathematical modelling; numerical research; hydrogen; oxygen.
References
1. Ackley M.W. Medical Oxygen Concentrators: A Review of Progress in Air Separation Technology, Adsorption, 2019, vol. 25, no. 8, pp. 1437-1474. DOI: 10.1007/s10450-019-00155-w
2. Shi Wenrong, Tian Caixia, Ding Zhaoyang, Han Zhiyang, Zhang Donghui. Review on Simulation, Optimization and Control of Pressure Swing Adsorption. Journal of Chemical Engineering of Chinese Universities, 2018, vol. 32, no. 1, pp. 8-15. DOI: 10.3969/j.issn.1003-9015.2018.01.002
3. Khajuria H., Pistikopoulos E.N. Optimization and Control of Pressure Swing Adsorption Processes Under Uncertainty. AIChE Journal, 2013, vol. 59, no. 1, pp. 120-131. DOI: 10.1002/aic.13783
4. Biegler L.T., Jiang L., Fox V.G. Recent Advances in Simulation and Optimal Design of Pressure Swing Adsorption Systems. Separation and Purification Reviews, 2004, vol. 33, no. 1, pp. 1-39. DOI: 10.1081/SPM-120039562
5. Papadias D., Lee S., Ahmed S. Facilitating Analysis of Trace Impurities in Hydrogen: Enrichment Based on the Principles of Pressure Swing Adsorption. International Journal of Hydrogen Energy, 2012, vol. 37, no. 19, pp. 14413-14423. DOI: 10.1016/j.ijhydene.2012.07.057
6. Cruz P., Magalhaes F. D., Mendes A. On the Optimization of Cyclic Adsorption Separation Processes. AIChE Journal, 2005, vol. 51, no. 5, pp. 1377-1395. DOI: 10.1002/aic.10400
7. Ogawa K., Inagaki Y., Ohno A. Numerical Analysis of O_2 Concentration, Gas-Zeolite Temperatures in Two Zeolite Columns for an Oxygen Concentrator. International Journal of Heat and Mass Transfer, 2019, vol. 129, pp. 238-254. DOI: 10.1016/j.ijheatmasstransfer.2018.09.052
8. Makarem M.A., Mofarahi M., Jafarian B., Lee Chang Ha. Simulation and Analysis of Vacuum Pressure Swing Adsorption Using the Differential Quadrature Method. Computers and Chemical Engineering, 2019, vol. 121, pp. 483-496. DOI: 10.1016/j.compchemeng.2018.11.017
9. Silva B., Solomon I., Ribeiro A.M., Lee U. Hwang, Hwang Young-kyu, Chang Jongsan, Loureiro J.M., Rodrigues A.E. H-2 Purification by Pressure Swing Adsorption using CuBTC. Separation and Purification Technology, 2013, vol. 118, pp. 744-756. DOI: 10.1016/j.seppur.2013.08.024
10. Li Huiru, Liao Zuwei, Sun Jingyuan, Jiang Bingbo, Wang Jingdai, Yang Yongrong. Modelling and Simulation of Two-bed PSA Process for Separating H2 from Methane Steam Reforming. Chinese Journal of Chemical Engineering, 2019, vol. 27, no. 8, pp. 1870-1878. DOI: 10.1016/j.cjche.2018.11.022
11. Tavan Y., Hosseini S.H., Olazar M. A Note on an Integrated Process of Methane Steam Reforming in Junction with Pressure-Swing Adsorption to Produce Pure Hydrogen: Mathematical Modeling. Industrial and Engineering Chemistry Research, 2015, vol. 54, no. 51, pp. 12937-12947. DOI: 10.1021/acs.iecr.5b01477
12. Akulinin E., Golubyatnikov O., Dvoretsky D., Dvoretsky S. Optimization and Analysis of Pressure Swing Adsorption Process for Oxygen Production from Air under Uncertainty. Chemical Industry and Chemical Engineering Quarterly, 2020, vol. 26, no. 1, pp. 89-104. DOI: 10.2298/CICEQ190414028A
13. Sanchez R., Riboldi L., Jakobsen H. Numerical Modelling and Simulation of Hydrogen Production via Four Different Chemical Reforming Processes: Process Performance and Energy Requirements. Canadian Journal of Chemical Engineering, 2017, vol. 95, no. 5, pp. 880-901. DOI: 10.1002/cjce.22758
14. Ribeiro A.M., Grande C.A., Lopes F.V., Loureiro J.M., Rodrigues A.E. A Parametric Study of Layered Bed PSA for Hydrogen Purification. Chemical Enginerring Science, 2008, vol. 63, no. 21, pp. 5258-5273. DOI: 10.1016/j.ces.2008.07.017
15. Santos J.C. Study of New Adsorbents and Operation Cycles for Medical PSA Units. Departamento de Engenharia Quimica Faculdade de Engenharia da Universidade do Porto, 2005.
16. Santos J.C., Cruz P., Regala T., Magalhaes F.D., Mendes A. High-Purity Oxygen Production by Pressure Swing Adsorption. Industrial and Engineering Chemistry Research, 2007, vol. 46, no. 2, pp. 591-599. DOI: 10.1021/ie060400g
17. Dubinin M.M. Fundamentals of the Theory of Adsorption in Micropores of Carbon Adsorbents: Characteristics of Their Adsorption Properties and Microporous Structures. Carbon, 1989, vol. 27, no. 3, pp. 457-467. DOI: 10.1016/0008-6223(89)90078-X
18. Dubinin M.M. Adsorbtsia i poristost' [Adsorption and Porosity]. Moscow, VAHZ, 1972. (in Russian)
19. Poling B., Prausnitz J., O'Connell J. The Properties of Gases and Liquids. New York, McGraw-Hill, 2001. DOI: 10.1036/0070116822
20. Bering B.P., Dubinin M.M., Serpinsky V.V. On Thermodynamics of Adsorption in Micropores. Journal of Colloid and Interface Science, 1972, vol. 38, no. 1, pp. 185-194. DOI: 10.1016/0021-9797(72)90233-0
21. Dubinin M.M., Yavich M. Dynamics of Adsorption of a Multicomponent Gas Mixture. Russian Journal of Applied Chemistry, 1936, vol. 9, no. 7, pp. 1191-1203.
22. Akulinin E.I., Golubyatnikov O.O., Dvoretsky D.S., Dvoretsky S.I. The Optimal Design of Pressure Swing Adsorption Process of Air Oxygen Enrichment under Uncertainty. Bulletin of the South Ural State University. Series: Mathematical Modelling, Programming and Computer Software, 2020, vol. 13, no. 2, pp. 5-16. DOI: 10.14529/mmp200201