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Modeling Aerosol Formation in an Electrically Heated Tobacco Product

Authors: Markus Nordlund, Arkadiusz K. Kuczaj


Philip Morris International (PMI) is developing a range of novel tobacco products with the potential to reduce individual risk and population harm in comparison to smoking cigarettes. One of these products is the Tobacco Heating System 2.2 (THS 2.2), (named as the Electrically Heated Tobacco System (EHTS) in this paper), already commercialized in a number of countries (e.g., Japan, Italy, Switzerland, Russia, Portugal and Romania). During use, the patented EHTS heats a specifically designed tobacco product (Electrically Heated Tobacco Product (EHTP)) when inserted into a Holder (heating device). The EHTP contains tobacco material in the form of a porous plug that undergoes a controlled heating process to release chemical compounds into vapors, from which an aerosol is formed during cooling. The aim of this work was to investigate the aerosol formation characteristics for realistic operating conditions of the EHTS as well as for relevant gas mixture compositions measured in the EHTP aerosol consisting mostly of water, glycerol and nicotine, but also other compounds at much lower concentrations. The nucleation process taking place in the EHTP during use when operated in the Holder has therefore been modeled numerically using an extended Classical Nucleation Theory (CNT) for multicomponent gas mixtures. Results from the performed simulations demonstrate that aerosol droplets are formed only in the presence of an aerosol former being mainly glycerol. Minor compounds in the gas mixture were not able to reach a supersaturated state alone and therefore could not generate aerosol droplets from the multicomponent gas mixture at the operating conditions simulated. For the analytically characterized aerosol composition and estimated operating conditions of the EHTS and EHTP, glycerol was shown to be the main aerosol former triggering the nucleation process in the EHTP. This implies that according to the CNT, an aerosol former, such as glycerol needs to be present in the gas mixture for an aerosol to form under the tested operating conditions. To assess if these conclusions are sensitive to the initial amount of the minor compounds and to include and represent the total mass of the aerosol collected during the analytical aerosol characterization, simulations were carried out with initial masses of the minor compounds increased by as much as a factor of 500. Despite this extreme condition, no aerosol droplets were generated when glycerol, nicotine and water were treated as inert species and therefore not actively contributing to the nucleation process. This implies that according to the CNT, an aerosol cannot be generated without the help of an aerosol former, from the multicomponent gas mixtures at the compositions and operating conditions estimated for the EHTP, even if all minor compounds are released or generated in a single puff.

Keywords: Aerosol, Classical Nucleation Theory (CNT), Electrically Heated Tobacco Product (EHTP), Electrically Heated Tobacco System (EHTS), modeling, multicomponent, nucleation.

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[1] H. Vehkam¨aki, Classical nucleation theory in multicomponent systems. Springer-Verlag Berlin Heidelberg, 2006.
[2] W. Hinds, Aerosol Technology. New York: Wiley-Interscience, 1999.
[3] H. Nguyen, K. Okuyama, T. Mimura, Y. Kousaka, R. Flagan, and J. Seinfeld, “Homogeneous and heterogeneous nucleation in a laminar flow aerosol generator,” Journal of Colloid And Interface Science, vol. 119, no. 2, pp. 491–504, 1987.
[4] M. Wilck, K. H¨ameri, F. Stratmann, and M. Kulmala, “Experimental and theoretical examination of homogeneous nucleation in a laminar flow reactor (ucpc),” Journal of Aerosol Science, vol. 27, no. SUPPL.1, pp. S587–S588, 1996.
[5] M. P. Anisimov, E. G. Fominykh, S. V. Akimov, and P. K. Hopke, “Vapor-gas/liquid nucleation experiments: A review of the challenges,” Journal of Aerosol Science, vol. 40, no. 9, pp. 733 – 746, 2009.
[6] C. Winkelmann, M. Nordlund, A. Kuczaj, S. Stolz, and B. Geurts, “Efficient second-order time-integration for single-species aerosol formation and evolution,” International Journal for Numerical Methods in Fluids, vol. 74 (5), pp. 313–334, 2014.
[7] E. Frederix, M. Stanic, A. Kuczaj, M. Nordlund, and B. Geurts, “Extension of the compressible PISO algorithm to single-species aerosol formation and transport,” International Journal of Multiphase Flow, vol. 74, pp. 184–194, 2015.
[8] H. Arstila, P. Korhonen, and M. Kulmala, “Ternary nucleation: Kinetics and application to water-ammonia-hydrochloric acid system,” Journal of Aerosol Science, vol. 30, pp. 131–138, 1999.
[9] G. Wilemski, “Composition of the critical nucleus in multicomponent vapor nucleation,” The Journal of Chemical Physics, vol. 80, no. 3, pp. 1370–1372, 1984.
[10] D. S. van Putten, “Efficient methods for N-component condensation,” Ph.D. dissertation, University of Twente, Enschede, The Netherlands, 2011.
[11] R. Becker and W. Dring, “Kinetische behandlung der keimbildung in bersttigten dmpfen,” Annalen der Physik, vol. 416, no. 8, pp. 719–752, 1935.
[12] “The OpenFOAM Foundation,”, 2015.
[13] H. Jasak, “Error analysis and estimation for the finite volume method with applications to fluid flows,” Ph.D. dissertation, Imperial College, University of London, 1996.
[14] M. Nordlund and A. Kuczaj, “Aerosol dosimetry modeling using computational fluid dynamics,” in Computational Systems Toxicology, ser. Methods in Pharmacology and Toxicology, J. Hoeng and M. Peitsch, Eds. Humana Press: Springer, 2015.
[15] R. Bird, W. Stewart, and E. Lightfoot, Transport Phenomena, revised second ed. New York: John Wiley & Sons Inc., 2007.
[16] D. Kashchiev, Nucleation: Basic Theory with Applications. Butterworth-Heinemann: Elsevier Science, 2000.
[17] G. Wilemski and B. E. Wyslouzil, “Binary nucleation kinetics. I. Self-consistent size distribution,” The Journal of Chemical Physics, vol. 103, no. 3, pp. 1127–1136, 1995.
[18] D. S. van Putten, S. P. Glazenborg, R. Hagmeijer, and C. H. Venner, “A multigrid method for N-component nucleation,” The Journal of Chemical Physics, vol. 135, no. 1, 2011.
[19] R. Issa, B. Ahmadi-Befrui, K. Beshay, and A. Gosman, “Solution of the implicitly discretised reacting flow equations by operator-splitting,” Journal of Computational Physics, vol. 93, pp. 388–410, 1991.
[20] R. Baker, “The development and significance of standards for smoking-machine methodology,” Beitrge zur Tabakforschung / Contributions to Tobacco Research, vol. 20, no. 1, pp. 23–41, 2002.
[21] “Philip Morris International,”, 2016.
[22] F. Barontini, A. Tugnoli, V. Cozzani, J. Tetteh, M. Jarriault, and I. Zinovik, “Volatile products formed in the thermal decomposition of a tobacco substrate,” Industrial & Engineering Chemistry Research, vol. 52, no. 42, pp. 14 984–14 997, 2013.
[23] V.-G. V. und Chemieingenieurwesen and V. Gesellschaft, VDI Heat Atlas, ser. Springer reference. Springer, 2010.
[24] “CAMEO Chemicals database,”, 2015.
[25] T. Daubert, R. Danner, and N. Design Institute for Physical Property Data (New York, Data compilation tables of properties of pure compounds. American Institute of Chemical Engineers, 1985, no. Teil 2.
[26] B. Poling, J. Prausnitz, and J. O’Connell, The properties of gases and liquids. McGraw-Hill, 2001.
[27] R. Warming and R. Beam, “Upwind second-order difference schemes and applications in aerodynamic flows,” AIAA Journal, vol. 14, pp. 1241–1249, 1976.