Analysis of Mass Transfer During Natural Gas Purification Process in a Vertical Tube

Abstract

The effects of axial and radial velocities on mass transfer during the purification of natural gas in a vertical pipe are studied numerically. The natural gas flowing inside a vertical channel and monoethanolamine (MEA) flowing as a film along the inner wall of the channel is taken together for the purification process. The direction of laminar flow of both fluids is gravity direction. The environment is assumed as isothermal. Comparisons are performed for the interface (wall) between the film and the gas in the presence and absence of axial mass flow. Grams’ finite

difference formulation are used to solve governing equations and solved by using Grams’ package code. It is found that the interface axial velocity effect on mass transfer can be neglected for low Reynolds numbers.

Keywords

• Natural gas
• Purification
• Mass transfer
• Reynolds number

References

1. -
2. Jou FY, Mather AE, Otto FD. “The Solubility of CO2 in a 30 Mass Percent Monoethanolamine Solution”, The Canadian J. of Chemical Engineering, 1995;73:140-147.
3. Li MH, Shen KP. “Solubility of Hydrogen Sulfide in Aqueous Mixtures of Monoethanolmine with N- Methyldiethanolamine”,
4. Engineering, 1993;38:105-108.
5. Faiz R, Al-Marzouqi M. “Insights on natural gas purification: Simultaneous absorption of CO2 and H2S using membrane contactors”, Sep. Pur. Technology, (2010).
6. Dong G, Li H, Chen V. “Factors affect defect-free Matrimid®
7. performance in natural gas purification”, J. Membrane Sci., 2010; 353:17-27.
8. Yeh AC, Bai H. “Comparison of Ammonia and Monoethanolamine Solvents to Reduce CO2 Greeenhouse Gas Emissions”, The Science of the Total Environment, 1999;228:121-133.

9. Pagella C, De Faveri DM. H2S “Gas Treatment by Iron Bioprocess”, Chem. Eng. Sci. 2000; 55:2185- 2194.
10. Lin SH, Shyu CT. “Performance Characteristics and Modeling of Carbondioxide Absorption by Amines in a Packed Column”, Waste Man. 1999;19: 255-262. Journal Chemical [3]
11. doi:1016/j.seppur.2010.11.005 [4] hollow fiber gas
12. separation [5] [6] [7] [8]
13. Yigit A. A “Numerical Study of Heat and Mass Transfer in Falling Film Absorber”, Int. Com. Heat Mass Transfer 1999;26:269-278.
14. Negny S, Meyer M, Prevost M. “Study of a Laminar Falling Film Flowing over a Wavy Wall Column.Part I –Numerical Investigation of the Flow Pattern and the Coupled Heat and Mass Transfer”, 2001;44:2137-2146.
15. Hughes DT, Bott TR. “Minimum Thickness of a Liquid Film Flowing Down a Vertical Tube”, Int. Int. J. Heat Mass Transfer 1998;41:253-260.
16. Negny N, Meyer M, Prevost M. “Enhancement of Absorbtion Efficiency for a Laminar Film Flow by Hydrodynamics Conditions Generated by a New Type of Column Wall”, Chemical Eng. J 2001;83:7-13.
17. Oztop HF, Akpınar EK. “Numerical and Experimental Analysis of Moisture Transfer for Convective Drying of Some Products”, Int. Comm. in Heat Mass Transfer 2008;35:169–177. Koyun T. “Doğal Gazın Tasfiyesi Örneğinde Kütle Transferinin İncelenmesi”, Doktora Tezi, Isparta, 2002. (In Turkish). Uysal,
18. Uygulamaları”, Gazi Üniversitesi 1996 (In Turkish). Kaufmann
19. Aerodynamik”, Berlin, Springer-Verlag 1963. Gram, Copenhagen, 1962.
20. Shen KP, Li MH. “Solubility of Carbon Dioxide in Aqueous Mixtures of Monoethanolamine with Methyldiethanolamine”, J. Chem. Eng. Data 1992;37:96-100.
21. Hillock AMW, Miller SJ, Koros WJ. “Crosslinked mixed matrix membranes for the purification of natural gas: Effects of sieve surface modification”, J. Membrane Sci. 2008; 314:193-199.
22. Bergh J, Zhu W, Groen JC, Kapteijn F, Moulijn JA, Yajima K, et al., “Natural gas purification with a DDR zeolite membrane; permeation modelling with maxwell-stefan equations”, Studies in Surface Science Catalysis 2007;170: 1021-1027.