Dynamics of a Fixed Bed Adsorption Column in the Kinetic Separation of Hexane Isomers in MOF ZIF-8
Abstract
A fixed bed adsorption mathematical model has been developed to describe the kinetic separation of hexane isomers when they flow through a packed bed containing the microporous Metal-Organic Framework (MOF) ZIF-8 adsorbent. The flow of inert and adsorbable species through the fixed bed is modeled with fundamental differential equations according to the mass and heat conservation laws, a general isotherm to describe adsorption equilibrium and a lumped kinetic mass transfer mechanism between bulk gas phase and the porous solid. It is shown that a proper combination of two characteristic times (the residence time of the gas in the fixed bed, \(\tau _{fb}\) and the characteristic time of diffusion of solutes into the pores \(\tau _{dif}\)) can lead to very different dynamics of fixed bed adsorbers where in a limiting case can gives rise to a spontaneous breakthrough curves of solutes. The numerical simulations of an experimental breakthrough curve with the developed mathematical model clearly explain the complete separation between linear n-Hexane (nHEX) and the respective branched isomers: 3-Methyl-Pentane (3MP) and 2, 2-Dimethyl-Butane (22DMB). The separation is due to significant differences in the diffusivity parameters \(\tau _{dif}\) between 3MP and 22DMB and the residence time of the gas mixture \(\tau _{fb}\) within the fixed bed. This work shows the importance of mathematical modelling for the comprehension and design of adsorption separation processes.
References
- 1.Bárcia, P.S., Silva, J.A.C., Rodrigues, A.E.: Ind. Eng. Chem. Res. 45, 4316–28 (2006)CrossRefGoogle Scholar
- 2.Cameron, I.T., Hangos, K.: Process Modelling and Model Analysis, 1st edn. Academic Press, Cambridge (2001). ISBN: 9780121569310Google Scholar
- 3.Chang, N., Gu, Z.Y., Yan, X.P.: Zeolitic imidazolate framework-8 nanocrystal coated capillary for molecular sieving of branched alkanes from linear alkanes along with high-resolution chromatographic separation of linear alkanes. J. Am. Chem. Soc. 132(39), 13645–7 (2010)CrossRefGoogle Scholar
- 4.Cusher, N.A.: UOP TIP and once-through zeolitic isomerization processes. In: Meyers, R.A. (ed.) Handbook of Petroleum Refining Processes, 3rd edn. McGraw Hill, New York (2004)Google Scholar
- 5.Danckwerts, P.V.: Continuous flow systems. Distribution of residence times. Chem. Eng. Sci. 2, 1–13 (1953)CrossRefGoogle Scholar
- 6.Deschamps, A., Jullian, S.: Adsorption in the oil and gas industry. In: Wauquier, J.P. (ed.) Petroleum Refining: Separation Processes, vol. 2. Technip, Paris (2000)Google Scholar
- 7.Ferreira, A.F.P., Mittelmeijer-Hazeleger, M.C., Granato, M.A., Martins, V.F.D., Rodrigues, A.E., Rothenberg, G.: Sieving di-branched from mono-branched and linear alkanes using ZIF-8: experimental proof and theoretical explanation. Phys. Chem. Chem. Phys. 15, 8795–8804 (2013)CrossRefGoogle Scholar
- 8.Finlayson, B.A.: The method of weighted residuals and variational principles. Soc. Ind. Appl. Math. (SIAM) (2014). ISBN-10: 1611973236Google Scholar
- 9.Glueckauf, E.: Formulae for diffusion into spheres and their application to chromatography. J. Chem. Soc. 51, 1540–1551 (1955)Google Scholar
- 10.Holcombe, T.C.: U.S. Patent 4,176,053 (1979)Google Scholar
- 11.Holcombe, T.C.: U.S. Patent 4,210,771 (1980)Google Scholar
- 12.Langmuir, I.: The adsorption of gases on plane surfaces of glass, mica and platinum. J. Am. Chem. Soc. 40, 1361–1403 (1918)CrossRefGoogle Scholar
- 13.Luebbers, M.T., Wu, T., Shen, L., Masel, R.I.: Trends in the adsorption of volatile organic compounds in a large-pore metal-organic framework, IRMOF-1. Langmuir 26(13), 11319–29 (2010)CrossRefGoogle Scholar
- 14.Mendes, P.A.P., Rodrigues, A.E., Horcajada, P., Serre, C., Silva, J.A.C.: Single and multicomponent adsorption of hexane isomers in the microporous ZIF-8. Micropor. Mesopor. Mater. 194, 146–156 (2014)CrossRefGoogle Scholar
- 15.Minkkinen, A., Mank, L., Jullian, S.: U.S. Patent 5,233,120 (1993)Google Scholar
- 16.Park, K.S., Ni, Z., Côte, A.P., Choi, J.Y., Huang, R., Uribe-Romo, F.J., Chae, H.K.: M. O’Keeffe, O. M. Yaghi. PNAS 103(27), 10186–91 (2006)Google Scholar
- 17.Peralta, D., Chaplais, G., Masseron, A.S., Barthelet, K., Pirngruber, G.D.: Ind. Eng. Chem. Res. 51(12), 4692–4702 (2012)CrossRefGoogle Scholar
- 18.Rice, R.G., Do, D.D.: Applied Mathematics and Modeling for Chemical Engineers. Wiley, New York (1995)Google Scholar
- 19.Ruthven, D.M.: Principles of Adsorption and Adsorption Processes. John Wiley and Sons, New York (1984)Google Scholar
- 20.Schiesser, W.E.: Computational Mathematics in Engineering and Applied Science: ODEs, DAEs, and PDEs. CRC Press, Boca Raton (1994)zbMATHGoogle Scholar
- 21.Villadsen, J.V., Michelsen, M.L.: Solution of Differential Equation Models by Polynomial Approximation. Prentice-Hall Inc., Englewood Cliffs, New Jersey (1978)zbMATHGoogle Scholar
- 22.Yang, R.T.: Gas Separation By Adsorption Processes. Butterworth, Stoneham (1987)Google Scholar
- 23.Zhang, K., Lively, R.P., Zhang, C., Chance, R.R., Koros, W.J., Sholl, D.S., Nair, S.: Exploring the framework hydrophobicity and flexibility of ZIF-8: from biofuel recovery to hydrocarbon separations. J. Phys. Chem. Lett. 4, 3618–3622 (2013)CrossRefGoogle Scholar