Advertisement

Adsorption

, Volume 26, Issue 2, pp 317–327 | Cite as

Modelling of the separation of long-chain normal paraffins from kerosene in a simulated moving bed process: effect of the desorbent

  • D. ArandaEmail author
  • V. I. Águeda
  • J. A. Delgado
  • M. A. Uguina
  • I. D. López
  • J. J. Lázaro
  • J. C. Perdomo
  • I. Barrio
Article
  • 187 Downloads

Abstract

Linear paraffins can be selectively separated from the rest of components of kerosene (branched hydrocarbons, aromatics and naphthenes) by means of liquid phase adsorption on 5A zeolite using the technology of simulated moving bed (SMB). In previous works, the kinetic and equilibrium parameters required for modelling and design of the SMB unit were obtained for pure n-paraffins and n-paraffin mixtures. However, the simulation of the SMB process indicated the presence of n-C5, used as a desorbent, in the separation zone, especially after the feed mixture is introduced. This finding motivated this work, in which n-paraffin mixtures (n-C10, n-C12, n-C14) including n-C5 were studied to address its influence in the process. The kinetic and equilibrium parameters for these mixtures were obtained and included in the model for the simulation of an SMB unit. While mixtures without n-C5 preferentially adsorbed shorter n-paraffins, it was found that including n-C5 in the mixtures reverses the selectivity of the adsorbent. In this case, longer n-paraffins are preferentially adsorbed, matching the trend observed for pure n-paraffins. In addition, n-C5 significantly increases the mobility of n-paraffins, as indicated in their higher mass transfer coefficients. The model was validated by comparing the predicted performance with the reported separation achieved by a commercial SMB unit that separates n-paraffins from hydrotreated kerosene fractions. The predicted separation performance is very similar to that achieved in our previous works, slightly improving the purity (99.6%) of the extract as a trade for a small loss in recovery (95.4%).

Keywords

n-Paraffins Mixtures 5A zeolite Adsorption Diffusion Simulated moving bed separation 

Abbreviations

bi

Adsorption affinity, m3 kg−1

ci

Concentration of component i, kg m−3

DL

Axial dispersión coefficient, s−1

dp

Particle diameter, m

kc

Micropore mass transfer coefficient, s−1

kmacro

Macropore mass transfer coefficient, m s−1

Q

Flow rate, m3 s−1

qi

Adsorbed concentration of component i, \({\text{kg}}_{\text{i}} \,{\text{kg}}^{ - 1}_{\text{ads}}\)

qmax,i

Máximum adsorption capacity of component i, \({\text{kg}}_{\text{i}} \,{\text{kg}}^{ - 1}_{\text{ads}}\)

si

Split fraction at the outlet of bed i

Sij

Selectivity of the adsorbent

u

Superficial velocity, m s−1

W

Mass of adsorbent, kg

y

Mass fraction

Greek symbols

\(\rho\)

Liquid density, kg m−3

\(\varepsilon\)

Column void fraction, \({\text{m}}^{ 3}_{\text{void}} \,{\text{m}}^{ - 3}_{\text{bed}}\)

Subscripts

i

ith component; ith bed

F

Feed condition

Superscripts

o

Pure component, reference pressure

Notes

Acknowledgements

We would like to show our gratitude to CEPSA QUÍMICA SA for supporting this work and helping in the research providing their insight in the topic. Also, we would like to thank the Spanish Ministry of Education for their financing through the FPU Grant Program (FPU16/01818).

References

  1. Águeda, V.I., Uguina, M.A., Delgado, J.A., Holik, M.T., Aranda, D., López, I.D., Lázaro, J.J., Peláez, J.: Equilibrium and kinetics of adsorption of high molecular weight n-paraffins on a calcium LTA molecular sieve. Adsorption 23, 257–269 (2017).  https://doi.org/10.1007/s10450-016-9846-1 CrossRefGoogle Scholar
  2. Aranda, D., Águeda, V.I., Delgado, J.A., Uguina, M.A., Holik, M.T., López, I.D., Lázaro, J.J., Perdomo, J.C., Barrio, I.: Modelling of the separation of normal paraffins from kerosene fractions by a simulated moving bed process. Adsorption 24, 667–681 (2018).  https://doi.org/10.1007/s10450-018-9973-y CrossRefGoogle Scholar
  3. Van Assche, T.R.C., Baron, G.V., Denayer, J.F.M.: An explicit multicomponent adsorption isotherm model: accounting for the size-effect for components with Langmuir adsorption behavior. Adsorption 24, 517–530 (2018).  https://doi.org/10.1007/s10450-018-9962-1 CrossRefGoogle Scholar
  4. Azevedo, D.C.S., Rodrigues, A.E.: Design of a simulated moving bed in the presence of mass-transfer resistances. AIChE J. 45, 956–966 (1999).  https://doi.org/10.1002/aic.690450506 CrossRefGoogle Scholar
  5. Bieser, H.J.: Process for separating normal paraffins (1977)Google Scholar
  6. Broughton, D.B., Neuzil, R.W., Pharis, J.M., Brearley, S.: The parex process for recovering paraxylene. Chem. Eng. Prog. 66, 70–75 (1970)Google Scholar
  7. Chung, S.F., Wen, C.Y.: Longitudinal dispersion of liquid flowing through fixed and fluidized beds. AIChE J. 14, 857–866 (1968)CrossRefGoogle Scholar
  8. Daems, I., Baron, G.V., Punnathanam, S., Snurr, R.Q., Denayer, J.F.M.: Molecular cage nestling in the liquid-phase adsorption of n-alkanes in 5A zeolite. J. Phys. Chem. C 111, 2191–2197 (2007).  https://doi.org/10.1021/jp0668145 CrossRefGoogle Scholar
  9. Denayer, J.F.M., Baron, G. V.: Molecular packing-induced selectivity effects in liquid adsorption in zeolites. In: Dunne, L.J., Manos, G. (eds.) Adsorption and Phase Behaviour in Nanochannels and Nanotubes, pp. 171–194. Springer, Dordrecht (2010)CrossRefGoogle Scholar
  10. Hatanaka, T., Ishida, M.: A new process for multicomponent continuous separation by combining multiple liquid chromatography columns. J. Chem. Eng. Jpn 25, 78–83 (1991)CrossRefGoogle Scholar
  11. Juza, M., Mazzotti, M., Morbidelli, M.: Simulated moving-bed chromatography and its application to chirotechnology. Trends Biotechnol. 18, 108–118 (2000).  https://doi.org/10.1016/S0167-7799(99)01419-5 CrossRefPubMedGoogle Scholar
  12. Kosswig, K.: Surfactants. In: Ullmann’s Encyclopedia of Industrial Chemistry, 7th edn. Wiley-VCH, New York (2011)Google Scholar
  13. Markovska, L.T., Meshko, V.D., Kiprijanova, R.T.: Modelling of microporous diffusion of N-paraffins in zeolite 5A. Korean J. Chem. Eng. 16, 285–291 (1999).  https://doi.org/10.1007/BF02707114 CrossRefGoogle Scholar
  14. Mata, V.G., Rodrigues, A.E.: Separation of ternary mixtures by pseudo-simulated moving bed chromatography. J. Chromatogr. A 939, 23–40 (2001).  https://doi.org/10.1016/S0021-9673(01)01335-8 CrossRefPubMedGoogle Scholar
  15. Mazzotti, M., Baciocchi, R., Storti, G., Morbidelli, M.: Vapor-phase SMB adsorptive separation of linear/nonlinear paraffins. Ind. Eng. Chem. Res. 35, 2313–2321 (1996).  https://doi.org/10.1021/ie950766l CrossRefGoogle Scholar
  16. Meyers, R.A.: Handbook of Petroleum Refining Processes. McGraw-Hill, New York (2004)Google Scholar
  17. Migliorini, C., Gentilini, A., Mazzotti, M., Morbidelli, M.: Design of simulated moving bed units under nonideal conditions. Ind. Eng. Chem. Res. 38, 2400–2410 (1999).  https://doi.org/10.1021/ie980262y CrossRefGoogle Scholar
  18. Migliorini, C., Mazzotti, M., Morbidelli, M.: Design of simulated moving bed multicomponent separations: Langmuir systems. Sep. Purif. Technol. 20, 79–96 (2000).  https://doi.org/10.1016/S1383-5866(00)00069-1 CrossRefGoogle Scholar
  19. Minceva, M., Rodrigues, A.E.: Modeling and simulation of a simulated moving bed for the separation of p-xylene. Ind. Eng. Chem. Res. 41, 3454–3461 (2002).  https://doi.org/10.1021/ie010095t CrossRefGoogle Scholar
  20. Punnathanam, S., Denayer, J.F.M., Daems, I., Baron, G.V., Snurr, R.Q.: Parallel tempering simulations of liquid-phase adsorption of n-alkane mixtures in zeolite LTA-5A. J. Phys. Chem. C 115, 762–769 (2011).  https://doi.org/10.1021/jp110627g CrossRefGoogle Scholar
  21. Raghuram, S., Wilcher, S.A.: The separation of n-paraffins from paraffin mixtures. Sep. Sci. Technol. 27, 1917–1954 (1992).  https://doi.org/10.1080/01496399208019457 CrossRefGoogle Scholar
  22. Rodrigues, A.E., Pereira, C., Minceva, M., Pais, L.S., Ribeiro, A.M., Ribeiro, A., Silva, M., Graça, N., Santos, J.C., Rodrigues, A.E., Pereira, C., Minceva, M., Pais, L.S., Ribeiro, A.M., Ribeiro, A., Silva, M., Graça, N., Santos, J.C.: Chapter 5—the parex process for the separation of p-xylene. Simulated Mov. Bed Technol. 1, 117–144 (2015a).  https://doi.org/10.1016/b978-0-12-802024-1.00005-7 CrossRefGoogle Scholar
  23. Rodrigues, A.E., Pereira, C., Minceva, M., Pais, L.S., Ribeiro, A.M., Ribeiro, A., Silva, M.S.P., Graça, N.S., Santos, J.C.: Simulated Moving Bed Technology. Principles, Design and Process Applications. Elsevier, Amsterdam (2015b)Google Scholar
  24. Schmidt-Traub, H., Schulteand, M., Seidel-Morgensten, A.: Preparative Chromatography. Wiley, Weinheim (2012)CrossRefGoogle Scholar
  25. Schulte, M., Strube, J.: Preparative enantioseparation by simulated moving bed chromatography. J. Chromatogr. A 906, 399–416 (2001).  https://doi.org/10.1016/S0021-9673(00)00956-0 CrossRefPubMedGoogle Scholar
  26. Seader, J.D., Seider, W.D., Lewin, D.R., Boulle, L., Rycrof, A.: Separation Process Principles, 3rd edn. Wiley, New York (2006)Google Scholar
  27. Shermann, J.D.: Synthetic zeolites and other microporous oxide molecular sieves. In: Proceedings of the National Academy of Science of the United States of America, pp. 3471–3478 (2000)CrossRefGoogle Scholar
  28. Silva, M.S.P., Rodrigues, A.E., Mota, J.P.B.: Modeling and simulation of an industrial-scale parex process. Am. Inst. Chem. Eng. 61, 1345–1363 (2015)CrossRefGoogle Scholar
  29. Storti, G., Masi, M., Carrà, S., Morbidelli, M.: Optimal design of multicomponent countercurrent adsorption separation processes involving nonlinear equilibria. Chem. Eng. Sci. 44, 1329–1345 (1989)CrossRefGoogle Scholar
  30. Tonkovich, A.L.Y., Carr, R.W.: Experimental evaluation of designs for the simulated moving bed separator. AIChE J. 42, 683–690 (1996)CrossRefGoogle Scholar
  31. Yang, R.T.: Gas Separation by Adsorption Processes. Butterworth, Boston (1987)Google Scholar

Copyright information

© Springer Science+Business Media, LLC, part of Springer Nature 2019

Authors and Affiliations

  1. 1.Universidad Complutense de MadridMadridSpain
  2. 2.Centro de Investigación CEPSA, QUÍMICA S.A.Alcalá de HenaresSpain
  3. 3.CEPSA QUÍMICAAlcalá de HenaresSpain

Personalised recommendations