, Volume 24, Issue 2, pp 203–219 | Cite as

Towards polymer grade ethylene production with Cu-BTC: gas-phase SMB versus PSA

  • Vanessa F. D. Martins
  • Ana M. Ribeiro
  • Jong-San Chang
  • José M. Loureiro
  • Alexandre Ferreira
  • Alírio E. Rodrigues


The recovery of ethylene as a product from ethylene/ethane mixtures by adsorptive processes has been attracting great interest due to the high operating and capital costs of the cryogenic distillation traditionally practiced. This search for novel economical ways to separate olefins from paraffins by adsorptive processes has motivated the appearance of improved materials. The trend of developing new materials, such as metal–organic frameworks (MOF) and the challenge of improving the existing technologies, such as pressure swing adsorption (PSA) and simulated moving bed (SMB) leave the horizon open for new alternatives. In the present work, PSA and SMB in gas phase were tested to produce ethylene at high purity on Cu-BTC MOF in beads form. For the first time, the olefin/paraffin separation by SMB technology, using a MOF as adsorbent, was achieved. Both technologies were successfully implemented experimentally and simulated. In the best cycle performed by VPSA for the 20/80 ethane/ethylene feed composition, the ethylene was obtained with a purity of 98.0% at a recovery of 70.2% and a productivity per unit mass of stationary phase of 1.55 molC2 h−1 kg−1adsorbent. Additionally, for the 50/50 ethane/ethylene mixture only 43.2% of the ethylene is recovered at a purity of 95.4% and a productivity of 0.52 molC2 h−1 kg1adsorbent. In the two cycles performed by SMB, to separate 39/61 ethane/ethylene mixture, ethylene was obtained with a purity of 95%, a recovery above 90% and productivity between 0.50 and 0.66 molC2 h−1 kg−1adsorbent. All the experiments were well predicted by the axial dispersion flow model with the LDF approximation.


Gas phase SMB PSA Olefin Adsorption MOF 



The authors acknowledge financial support provided by: project FCOMP-01-0124-FEDER-027458 (Ref. FCT EXCL/QEQPRS/0308/2012) financed by Fundação para a Ciência e a Tecnologia (FCT, Portugal) and FEDER under Programme COMPETE; project “AIProcMat@N2020 - Advanced Industrial Processes and Materials for a Sustainable Northern Region of Portugal 2020”, with the reference NORTE-01-0145-FEDER-000006, supported by Norte Portugal Regional Operational Programme (NORTE 2020), under the Portugal 2020 Partnership Agreement, through the European Regional Development Fund (ERDF); and of Project POCI-01-0145-FEDER-006984 – Associate Laboratory LSRE-LCM funded by ERDF through COMPETE2020 - Programa Operacional Competitividade e Internacionalização (POCI) – and by national funds through FCT - Fundação para a Ciência e a Tecnologia.

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  1. AFPM: What is a Cracker and Why Should I Care? (2016). Accessed 20 Jun 2016
  2. Aguado, S., Bergeret, G., Daniel, C., Farrusseng, D.: Absolute molecular sieve separation of ethylene/ethane mixtures with silver zeolite a. J. Am. Chem. Soc. 134(36), 14635–14637 (2012). CrossRefGoogle Scholar
  3. Ahmed, M.J., Theydan, S.K.: Isotherms and thermodynamics studies for binary adsorption of methane and ethane on 4A molecular sieve zeolite. J. Porous Mater. 21(3), 303–310 (2014). CrossRefGoogle Scholar
  4. Alaerts, L., Kirschhock, C.E.A., Maes, M., van der Veen, M.A., Finsy, V., Depla, A., Martens, J.A., Baron, G.V., Jacobs, P.A., Denayer, J.E.M., De Vos, D.E.: Selective adsorption and separation of xylene isomers and ethylbenzene with the microporous vanadium(IV) terephthalate MIL-47. Angew Chem. Int. Ed. 46(23), 4293–4297 (2007). CrossRefGoogle Scholar
  5. Anson, A., Wang, Y., Lin, C.C.H., Kuznicki, T.M., Kuznicki, S.M.: Adsorption of ethane and ethylene on modified ETS-10. Chem. Eng. Sci. 63(16), 4171–4175 (2008). CrossRefGoogle Scholar
  6. Babarao, R., Hu, Z.Q., Jiang, J.W., Chempath, S., Sandler, S.I.: Storage and separation of CO2 and CH4 in silicalite, C-168 schwarzite, and IRMOF-1: a comparative study from monte carlo simulation. Langmuir 23(2), 659–666 (2007). CrossRefGoogle Scholar
  7. Barcia, P.S., Zapata, F., Silva, J.A.C., Rodrigues, A.E., Chen, B.L.: Kinetic separation of hexane isomers by fixed-bed adsorption with a microporous metal-organic framework. J. Phys. Chem. B. 111(22), 6101–6103 (2007). CrossRefGoogle Scholar
  8. BASF: Polymer Grade Ethylene. (2014). Accessed 04 Mar 2016
  9. Bastin, L., Barcia, P.S., Hurtado, E.J., Silva, J.A.C., Rodrigues, A.E., Chen, B.L.: A microporous metal-organic framework for separation of CO2/N2 and CO2/CH4 by fixed-bed adsorption. J. Phys. Chem. C 112(5), 1575–1581 (2008). CrossRefGoogle Scholar
  10. Bentley, J., Huang, Q.L., Kawajiri, Y., Eic, M., Seidel-Morgenstern, A.: Optimizing the separation of gaseous enantiomers by simulated moving bed and pressure swing adsorption. Adsorption 17(1), 159–170 (2011). CrossRefGoogle Scholar
  11. Bezus, A.G., Kiselev, A.V., Sedlacek, Z., Du, P.Q.: Adsorption of ethane and ethylene on X-zeolites containing Li+, Na+, K+, Rb + and Cs + cations. Trans. Faraday Soc. 67(578), 468–482 (1971). CrossRefGoogle Scholar
  12. Bezus, A.G., Kiselev, A.V., Du, P.Q.: The influence of size, charge and concentration of exchange cations on the adsorption of ethane and ethylene by zeolites. J. Colloid Interface Sci. 40(2), 223–232 (1972). CrossRefGoogle Scholar
  13. Bird, R.B., Stewart, W.E., Lightfoot, E.N.: Transport phenomena. Wiley, Hoboken (2007)Google Scholar
  14. Bloch, E.D., Queen, W.L., Krishna, R., Zadrozny, J.M., Brown, C.M., Long, J.R.: Hydrocarbon Separations in a metal-organic framework with open iron(II) coordination sites. Science 335(6076), 1606–1610 (2012). CrossRefGoogle Scholar
  15. Broughton, D.B., Gerhold, C.G.: Continuous sorption process employing fixed bed of sorbent and moving inlets and outlets. US Patent (1961)Google Scholar
  16. Campo, M.C., Ribeiro, A.M., Ferreira, A., Santos, J.C., Lutz, C., Loureiro, J.M., Rodrigues, A.E.: New 13X zeolite for propylene/propane separation by vacuum swing adsorption. Sep. Purif. Technol. 103, 60–70 (2013). CrossRefGoogle Scholar
  17. Campo, M.C., Baptista, M.C., Ribeiro, A.M., Ferreira, A., Santos, J.C., Lutz, C., Loureiro, J.M., Rodrigues, A.E.: Gas phase SMB for propane/propylene separation using enhanced 13X zeolite beads. Adsorption 20(1), 61–75 (2014). CrossRefGoogle Scholar
  18. Chen, B.L., Liang, C.D., Yang, J., Contreras, D.S., Clancy, Y.L., Lobkovsky, E.B., Yaghi, O.M., Dai, S.: A microporous metal-organic framework for gas-chromatographic separation of alkanes. Angew Chem. Int. Ed. 45(9), 1390–1393 (2006). CrossRefGoogle Scholar
  19. Chui, S.S.Y., Lo, S.M.F., Charmant, J.P.H., Orpen, A.G., Williams, I.D.: A chemically functionalizable nanoporous material [Cu3(TMA)(2)(H2O)(3)](n). Science 283(5405), 1148–1150 (1999). CrossRefGoogle Scholar
  20. Cruz, F.J.A.L., Esteves, I.A.A.C., Mota, J.P.B.: Adsorption of light alkanes and alkenes onto single-walled carbon nanotube bundles: langmuirian analysis and molecular simulations. Colloid Surf. A 357(1–3), 43–52 (2010). CrossRefGoogle Scholar
  21. Da Silva, F.A., Rodrigues, A.E.: Propylene/propane separation by pressure swing adsorption. Adsorpt. Sci. Technol. 2000:537–541 (2000). CrossRefGoogle Scholar
  22. Da Silva, F.A., Rodrigues, A.E.: Propylene/propane separation by vacuum swing adsorption using 13X zeolite. Aiche J. 47(2), 341–357 (2001a). CrossRefGoogle Scholar
  23. Da Silva, F.A., Rodrigues, A.E.: Vacuum swing adsorption for propylene/propane separation with 4A zeolite. Ind. Eng. Chem. Res. 40(24), 5758–5774 (2001b). CrossRefGoogle Scholar
  24. Da Silva, F.A., Silva, J.A., Rodrigues, A.E.: A general package for the simulation of cyclic adsorption processes. Adsorption 5(3), 229–244 (1999). CrossRefGoogle Scholar
  25. Danner, R.P., Choi, E.C.F.: Mixture adsorption equilibria of ethane and ethylene on 13x molecular-sieves. Ind. Eng. Chem. Fund. 17(4), 248–253 (1978). CrossRefGoogle Scholar
  26. Do, D.D., Do, H.D.: Non-isothermal effects on adsorption kinetics of hydrocarbon mixtures in activated carbon. Sep. Purif. Technol. 20(1), 49–65 (2000). CrossRefGoogle Scholar
  27. Dybtsev, D.N., Chun, H., Yoon, S.H., Kim, D., Kim, K.: Microporous manganese formate: a simple metal-organic porous material with high framework stability and highly selective gas sorption properties. J. Am. Chem. Soc. 126(1), 32–33 (2004). CrossRefGoogle Scholar
  28. Ferreira, A.F.P., Santos, J.C., Plaza, M.G., Lamia, N., Loureiro, J.M., Rodrigues, A.E.: Suitability of Cu-BTC extrudates for propane-propylene separation by adsorption processes. Chem. Eng. J. 167(1), 1–12 (2011). CrossRefGoogle Scholar
  29. Finsy, V., Verelst, H., Alaerts, L., De Vos, D., Jacobs, P.A., Baron, G.V., Denayer, J.F.M.: Pore-filling-dependent selectivity effects in the vapor-phase separation of xylene isomers on the metal-organic framework MIL-47. J. Am. Chem. Soc. 130(22), 7110–7118 (2008). CrossRefGoogle Scholar
  30. Fischer, M., Gomes, J.R.B., Froba, M., Jorge, M.: Modeling adsorption in metal-organic frameworks with open metal sites: propane/propylene separations. Langmuir 28(22), 8537–8549 (2012). CrossRefGoogle Scholar
  31. Gomes, P.S., Lamia, N., Rodrigues, A.E.: Design of a gas phase simulated moving bed for propane/propylene separation. Chem. Eng. Sci. 64(6), 1336–1357 (2009). CrossRefGoogle Scholar
  32. Granato, M.A., Martins, V.D., Santos, J.C., Jorge, M., Rodrigues, A.E.: From molecules to processes: molecular simulations applied to the design of simulated moving bed for ethane/ethylene separation. Can. J. Chem. Eng. 92(1), 148–155 (2014). CrossRefGoogle Scholar
  33. Grande, C.A., Rodrigues, A.E.: Propane/propylene separation by pressure swing adsorption using zeolite 4A. Ind. Eng. Chem. Res. 44(23), 8815–8829 (2005). CrossRefGoogle Scholar
  34. Grande, C.A., Poplow, F., Rodrigues, A.E.: Vacuum pressure swing adsorption to produce polymer-grade propylene. Sep. Sci. Technol. 45(9), 1252–1259 (2010). CrossRefGoogle Scholar
  35. Grande, C.A., Lind, A., Vistad, Ø, Akporiaye, D.: Olefin–paraffin separation using calcium-ETS-4. Ind. Eng. Chem. Res. 53(40), 15522–15530 (2014). CrossRefGoogle Scholar
  36. ICIS: Ethylene Production and Manufacturing Process.. (2007a). Accessed 20 Jun 2016
  37. ICIS: Ethylene Uses and Market Data. (2007b). Accessed 20 Jun 2016
  38. Jiang, J.W., Sandler, S.I.: Monte Carlo simulation for the adsorption and separation of linear and branched alkanes in IRMOF-1. Langmuir 22(13), 5702–5707 (2006). CrossRefGoogle Scholar
  39. Jorge, M., Lamia, N., Rodrigues, A.E.: Molecular simulation of propane/propylene separation on the metal-organic framework CuBTC. Colloid Surf. A 357(1–3), 27–34 (2010). CrossRefGoogle Scholar
  40. Jorge, M., Fischer, M., Gomes, J.R.B., Siquet, C., Santos, J.C., Rodrigues, A.E.: Accurate model for predicting adsorption of olefins and paraffins on MOFs with open metal sites. Ind. Eng. Chem. Res. 53(40), 15475–15487 (2014). CrossRefGoogle Scholar
  41. Juza, M., Di Giovanni, O., Biressi, G., Schurig, V., Mazzotti, M., Morbidelli, M.: Continuous enantiomer separation of the volatile inhalation anesthetic enflurane with a gas chromatographic simulated moving bed unit. J. Chromatogr. A 813(2), 333–347 (1998). CrossRefGoogle Scholar
  42. Keskin, S., Sholl, D.S.: Screening metal-organic framework materials for membrane-based methane/carbon dioxide separations. J. Phys. Chem. C 111(38), 14055–14059 (2007). CrossRefGoogle Scholar
  43. Kolmetz, K.: Ethylene splitter (Engineering Design Guideline).. (2012). Accessed 21 Jun 2016
  44. Lamia, N., Wolff, L., Leflaive, P., Gomes, P.S., Grande, C.A., Rodrigues, A.E.: Propane/propylene separation by simulated moving bed I. Adsorption of propane, propylene and isobutane in pellets of 13X zeolite. Sep. Sci. Technol. 42(12), 2539–2566 (2007). CrossRefGoogle Scholar
  45. Lamia, N., Jorge, M., Granato, M.A., Paz, F.A.A., Chevreau, H., Rodrigues, A.E.: Adsorption of propane, propylene and isobutane on a metal-organic framework: molecular simulation and experiment. Chem. Eng. Sci. 64(14), 3246–3259 (2009). CrossRefGoogle Scholar
  46. Martins, V.D., Ribeiro, A.M., Plaza, M.G., Santos, J.C., Loureiro, J.M., Ferreira, A., Rodrigues, A.E.: Gas-phase simulated moving bed: propane/propylene separation on 13X zeolite. J. Chromatogr. A 1423, 136–148 (2015a). CrossRefGoogle Scholar
  47. Martins, V.F.D., Ribeiro, A.M., Ferreira, A., Lee, U.H., Hwang, Y.K., Chang, J.S., Loureiro, J.M., Rodrigues, A.E.: Ethane/ethylene separation on a copper benzene-1,3,5-tricarboxylate MOF. Sep. Purif. Technol. 149, 445–456 (2015b). CrossRefGoogle Scholar
  48. Martins, V.F.D., Ribeiro, A.M., Santos, J.C., Loureiro, J.M., Gleichmann, K., Ferreira, A., Rodrigues, A.E.: Development of gas-phase smb technology for light olefin/paraffin separations. Aiche J. 62(7), 2490–2500 (2016). CrossRefGoogle Scholar
  49. Mazzotti, M., Storti, G., Morbidelli, M.: Robust design of countercurrent adsorption separation processes: 2. Multicomponent systems. Aiche J. 40(11), 1825–1842 (1994). CrossRefGoogle Scholar
  50. Mazzotti, M., Baciocchi, R., Storti, G., Morbidelli, M.: Vapor-phase SMB adsorptive separation of linear/nonlinear paraffins. Ind. Eng. Chem. Res. 35(7), 2313–2321 (1996). CrossRefGoogle Scholar
  51. McKetta, J.J., Cunningham, W.A.: Encyclopedia of chemical processing and design: Volume 20—Ethanol as Fuel: options: advantages, and disadvantages to exhaust stacks: cost. M. Dekker, New York (1976)Google Scholar
  52. Minceva, M.: Separation/isomerization of xylenes by simulated moving bed technology. University of Porto, Porto (2004)Google Scholar
  53. Mofarahi, M., Salehi, S.M.: Pure and binary adsorption isotherms of ethylene and ethane on zeolite 5A. Adsorption 19(1), 101–110 (2013). CrossRefGoogle Scholar
  54. Mofarahi, M., Sadrameli, M., Towfighi, J.: Four-bed vacuum pressure swing adsorption process for propylene/propane separation. Ind. Eng. Chem. Res. 44(5), 1557–1564 (2005). CrossRefGoogle Scholar
  55. Nakahara, T., Hirata, M., Omori, T.: Adsorption of hydrocarbons on carbon molecular-sieve. J. Chem. Eng. Data 19(4), 310–313 (1974). CrossRefGoogle Scholar
  56. Narin, G., Martins, V.F.D., Campo, M., Ribeiro, A.M., Ferreira, A., Santos, J.C., Schumann, K., Rodrigues, A.E.: Light olefins/paraffins separation with 13X zeolite binderless beads. Sep. Purif. Technol. 133, 452–475 (2014). CrossRefGoogle Scholar
  57. Newalkar, B.L., Choudary, N.V., Turaga, U.T., Vijayalakshmi, R.P., Kumar, P., Komarneni, S., Bhat, T.S.G.: Adsorption of light hydrocarbons on HMS type mesoporous silica. Microporous Mesoporous Mater. 65(2–3), 267–276 (2003). CrossRefGoogle Scholar
  58. Pan, L., Olson, D.H., Ciemnolonski, L.R., Heddy, R., Li, J.: Separation of hydrocarbons with a microporous metal-organic framework. Angew Chem. Int. Ed. 45(4), 616–619 (2006a). CrossRefGoogle Scholar
  59. Pan, L., Parker, B., Huang, X.Y., Olson, D.H., Lee, J., Li, J.: Zn(tbip) (H(2)tbip = 5-tert-butyl isophthalic acid): a highly stable guest-free microporous metal organic framework with unique gas separation capability. J. Am. Chem. Soc. 128(13), 4180–4181 (2006b). CrossRefGoogle Scholar
  60. Park, J.H., Han, S.S., Kim, J.N., Cho, S.H.: Vacuum swing adsorption process for the separation of ethylene/ethane with AgNO3/clay adsorbent. Korean J. Chem. Eng. 21(1), 236–245 (2004). CrossRefGoogle Scholar
  61. Plaza, M.G., Ribeiro, A.M., Ferreira, A., Santos, J.C., Lee, U.H., Chang, J.S., Loureiro, J.M., Rodrigues, A.E.: Propylene/propane separation by vacuum swing adsorption using Cu-BTC spheres. Sep. Purif. Technol. 90, 109–119 (2012). CrossRefGoogle Scholar
  62. Poling, B., Prausnitz, J., Connell, J.O.: The properties of gases and liquids. McGraw-Hill Education, New York (2000)Google Scholar
  63. Production: Growth is the Norm. In: Chemical and Engineering News, vol. 84. pp. 59–236. (2006)Google Scholar
  64. PSE: gProms - The world’s leading Advanced Process Modelling platform. (2017). Accessed 18 Aug 2017
  65. Ram, A.: Fundamentals of polymer engineering. Plenum Press, New York (1997)CrossRefGoogle Scholar
  66. Rege, S.U., Yang, R.T.: Propane/propylene separation by pressure swing adsorption: sorbent comparison and multiplicity of cyclic steady states. Chem. Eng. Sci. 57(7), 1139–1149 (2002). CrossRefGoogle Scholar
  67. Rege, S.U., Padin, J., Yang, R.T.: Olefin/paraffin separations by adsorption: pi-complexation vs. kinetic separation. Aiche J. 44(4), 799–809 (1998). CrossRefGoogle Scholar
  68. Shi, M., Lin, C.C.H., Kuznicki, T.M., Hashisho, Z., Kuznicki, S.M.: Separation of a binary mixture of ethylene and ethane by adsorption on Na-ETS-10. Chem. Eng. Sci. 65(11), 3494–3498 (2010). CrossRefGoogle Scholar
  69. Shi, M., Avila, A.M., Yang, F., Kuznicki, T.M., Kuznicki, S.M.: High pressure adsorptive separation of ethylene and ethane on Na-ETS-10. Chem. Eng. Sci. 66(12), 2817–2822 (2011). CrossRefGoogle Scholar
  70. Sircar, S.: Pressure swing adsorption. Ind. Eng. Chem. Res. 41(6), 1389–1392 (2002). CrossRefGoogle Scholar
  71. Sivakumar, S.V., Rao, D.P.: Adsorptive separation of gas mixtures: mechanistic view, sharp separation and process intensification. Chem. Eng. Process. 53, 31–52 (2012). CrossRefGoogle Scholar
  72. Skarstrom, C.W.: Method and apparatus for fractionating gaseous mixtures by adsorption. US Patent (1960)Google Scholar
  73. Skarstrom, C.W.: Oxygen concentration process. US Patent (1966)Google Scholar
  74. Storti, G., Mazzotti, M., Furlan, L.T., Morbidelli, M., Carra, S.: Performance of a 6-Port simulated moving-bed pilot-plant for vapor-phase adsorption separations. Sep. Sci. Technol. 27(14), 1889–1916 (1992). CrossRefGoogle Scholar
  75. Tondeur, D., Wankat, P.C.: Gas purification by pressure swing adsorption. Sep. Purif. Method 14(2), 157–212 (1985). CrossRefGoogle Scholar
  76. van Miltenburg, A., Zhu, W., Kapteijn, F., Moulijn, J.A.: Adsorptive separation of light olefin/paraffin mixtures. Chem. Eng. Res. Des. 84(A5), 350–354 (2006). CrossRefGoogle Scholar
  77. Van Assche, T.R.C., Duerinck, T., Gutierrez Sevillano, J.J., Calero, S., Baron, G.V., Denayer, J.F.M.: High adsorption capacities and two-step adsorption of polar adsorbates on copper benzene-1,3,5-tricarboxylate metal-organic framework. J. Phys. Chem. C 117(35), 18100–18111 (2013). CrossRefGoogle Scholar
  78. Wang, Q.M., Shen, D.M., Bulow, M., Lau, M.L., Deng, S.G., Fitch, F.R., Lemcoff, N.O., Semanscin, J.: Metallo-organic molecular sieve for gas separation and purification. Microporous Mesoporous Mater 55(2), 217–230 (2002). CrossRefGoogle Scholar
  79. Wang, S.Y., Yang, Q.Y., Zhong, C.L.: Adsorption and separation of binary mixtures in a metal-organic framework Cu-BTC: a computational study. Sep. Purif. Technol. 60(1), 30–35 (2008). CrossRefGoogle Scholar
  80. Yang, Q.Y., Zhong, C.L.: Molecular simulation of carbon dioxide/methane/hydrogen mixture adsorption in metal-organic frameworks. J. Phys. Chem. B. 110(36), 17776–17783 (2006). CrossRefGoogle Scholar
  81. Yang, Q.Y., Xue, C.Y., Zhong, C.L., Chen, J.F.: Molecular simulation of separation of CO2 from flue gases in Cu-BTC metal-organic framework. Aiche J. 53(11), 2832–2840 (2007). CrossRefGoogle Scholar
  82. Zhang, L., Wang, Q., Wu, T., Liu, Y.C.: Understanding adsorption and interactions of alkane isomer mixtures in isoreticular metal-organic frameworks. Chem. Eur. J. 13(22), 6387–6396 (2007). CrossRefGoogle Scholar
  83. Zimmermann, H., Walzl, R.: Ethylene. In: Ullmann’s encyclopedia of industrial chemistry. Wiley, Hoboken (2002)Google Scholar

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Authors and Affiliations

  • Vanessa F. D. Martins
    • 1
  • Ana M. Ribeiro
    • 1
  • Jong-San Chang
    • 2
    • 3
  • José M. Loureiro
    • 1
  • Alexandre Ferreira
    • 1
  • Alírio E. Rodrigues
    • 1
  1. 1.Laboratory of Separation and Reaction Engineering - Laboratory of Catalysis and Materials (LSRE-LCM), Department of Chemical EngineeringUniversity of PortoPortoPortugal
  2. 2.Catalysis Center for Molecular EngineeringKorea Research Institute of Chemical Technology (KRICT)DaejeonRepublic of Korea
  3. 3.Department of ChemistrySungkyunkwan UniversitySuwonRepublic of Korea

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