, 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


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%).


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



Adsorption affinity, m3 kg−1


Concentration of component i, kg m−3


Axial dispersión coefficient, s−1


Particle diameter, m


Micropore mass transfer coefficient, s−1


Macropore mass transfer coefficient, m s−1


Flow rate, m3 s−1


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


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


Split fraction at the outlet of bed i


Selectivity of the adsorbent


Superficial velocity, m s−1


Mass of adsorbent, kg


Mass fraction

Greek symbols


Liquid density, kg m−3


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



ith component; ith bed


Feed condition



Pure component, reference pressure



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).


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© 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

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