**Commenced**in January 2007

**Frequency:**Monthly

**Edition:**International

**Paper Count:**31108

##### Hydrodynamic Simulation of Co-Current and Counter Current of Column Distillation Using Euler Lagrange Approach

**Authors:**
H. Troudi,
M. Ghiss,
Z. Tourki,
M. Ellejmi

**Abstract:**

Packed columns of liquefied petroleum gas (LPG) consists of separating the liquid mixture of propane and butane to pure gas components by the distillation phenomenon. The flow of the gas and liquid inside the columns is operated by two ways: The co-current and the counter current operation. Heat, mass and species transfer between phases represent the most important factors that influence the choice between those two operations. In this paper, both processes are discussed using computational CFD simulation through ANSYS-Fluent software. Only 3D half section of the packed column was considered with one packed bed. The packed bed was characterized in our case as a porous media. The simulations were carried out at transient state conditions. A multi-component gas and liquid mixture were used out in the two processes. We utilized the Euler-Lagrange approach in which the gas was treated as a continuum phase and the liquid as a group of dispersed particles. The heat and the mass transfer process was modeled using multi-component droplet evaporation approach. The results show that the counter-current process performs better than the co-current, although such limitations of our approach are noted. This comparison gives accurate results for computations times higher than 2 s, at different gas velocity and at packed bed porosity of 0.9.

**Keywords:**
Heat Transfer,
mass transfer,
co-current,
counter current,
Euler Lagrange model

**Digital Object Identifier (DOI):**
doi.org/10.5281/zenodo.1128797

**References:**

[1] V. R. Dhole, B. Linnhoff, "Distillation column targets", Computers Chemical Engineering, vol. 17, n° 516, pp. 549-560, 1993.

[2] R W. Rousseau, Handbook of Separation Process Technology. Georgia Institute of Technology, 1987.

[3] M. Soos, E. Graczova, J. Markos, A. Molnar, P. Steltenpohl, "Design and simulation of a distillation column for separation of di-chloropropane from a multi-component mixture", Chemical Engineering and Processing, vol. 42, pp. 273-284, 2003.

[4] A. Ghareghashia, S. Ghadera, b, H. Hashemipoura, H. R. Moghadamc, “A comparison of co-current and counter-current modes for Fischer–Tropsch synthesis in two consecutive reactors of oxidative coupling of methane and Fischer–Tropsch”, Journal of Natural Gas Science and Engineering, vol. 14, pp. 1-16, 2013.

[5] C.T. Blaisdell, K. Kammermeyer “Counter-current and co-current gas separation”, Chemical Engineering Science, vol. 28, n° 6, 1973.

[6] R. Banerjee, R. Gopinath, “CFD Analysis to study evaporation of a single Ethanol / Iso- binary mixture droplet”, ASME-JSME-KSME 2011 Joint Fluids Engineering Conference, July 2011.

[7] M. Vohra, “Evaporation of Ethanol / Iso-Octane Droplets (A Binary Component Fuel)”, 2011.

[8] V. Shirodkar, "urea -water droplet phase change and reaction modelling: multi -component evaporation approach", Frontiers in heat and mass transfer (FHMT), vol. 7, n° 5, 2016.

[9] A. Nasr, A. Belhadj Mohamed, J. Orfi, C. Debissi, S. Ben Nasrallah, “Evaporation of a thin binary liquid film covering one plate of a vertical Channel”, Revue des Energies Renouvelables, vol. 11, n°4, pp. 611 – 622, 2008.

[10] T. Seno, S. Uchida, S. Tsuyutani, "Mass transfer in counter current and cocurrent bubble columns",Chemical Engineering Technology, vol. 13, n° 1, pp. 113–118, 1990.

[11] J. F. Widmann, E. J. Davis, "Evaporation of Multicomponent Droplets", Aerosol Science and Technology, vol. 27, n° 2, pp. 243-254, 1997.

[12] P. Niegodajew, D. Asendrych, M. Marek and S. Drobniak, “Modelling liquid redistribution in a packed bed”, Journal of Physics, vol. 530, 2014.

[13] M.J.V. Goldschmidt, B.P.B. Hoomans, J.A.M. Kuipers, “Detailed comparison of Euler-Lagrange and Euler-Euler models for simulation of dense gas fluidised beds", 10th Workshop on Two-phase Flow Predictions, pp. 285-299, April 2002.

[14] Z. Zhang, Q. Chen, “Comparison of the Eulerian and Lagrangian methods for predicting particle transport in enclosed spaces” Atmospheric environment, vol. 41, n° 25, pp. 5236-5248, August 2007.

[15] J.-P. Wauquier, “Tome 1: Pétrole brut, Produits pétroliers, Schéma de fabrication,” Le raffinage du pétrole, p. 255, 1994.

[16] “Ansys fluent 12.0: Theory Guide,” 2009.