10th International Aerosol Conference September 2 - September 7, 2018 America's Center Convention Complex St. Louis, Missouri, USA
Abstract View
Numerical Model for the Aerosol Formation Process in an Electrically Heated Tobacco Product
MARKUS NORDLUND, Philip Morris Products S.A., Switzerland
Abstract Number: 781 Working Group: Aerosol Modeling
Abstract Philip Morris International is developing a range of products that have the potential to reduce individual risk and population harm compared with continued smoking. One of these products is the Electrically Heated Tobacco System (EHTS) (also referred to as the Tobacco Heating System 2.2), which is currently commercialized in more than 30 markets. During use, the patented EHTS heats a specifically designed tobacco product (Electrically Heated Tobacco Product (EHTP)) without combustion when inserted into the Holder (heating device). The EHTP contains a specially manufactured tobacco material in the form of a porous plug that undergoes a controlled heating process to release chemical compounds (present in the tobacco material) into vapors. As there is no combustion of the tobacco substrate, no smoke is formed, and the nicotine-containing respirable aerosol is instead formed with the help of an aerosol former (glycerol) added to the tobacco material.
The aim of this work was to numerically model the aerosol formation process for realistic operating conditions of the EHTS and for relevant gas-vapor mixture compositions measured in the generated EHTP aerosol. Chemical analysis of the EHTP aerosol showed that it consisted mostly of water, glycerol, and nicotine as well as other compounds at much lower concentrations. An extended Classical Nucleation Theory (CNT) for multicomponent gas-vapor mixtures was used to numerically model the aerosol formation taking place in the EHTP during use when operated in the Holder. Cases with and without glycerol present in the tobacco substrate were simulated to specifically investigate the role that glycerol plays during the aerosol formation process.
Results from the performed numerical simulations demonstrate that glycerol was the compound triggering aerosol formation under the simulated operating conditions of the EHTS and EHTP. Water and other compounds in the gas-vapor mixture were not able to reach supersaturation and therefore could not generate aerosol droplets from the multicomponent gas-vapor mixture at the operating conditions simulated. This implies that according to the extended CNT, an aerosol will only form under the tested operating conditions when there is an aerosol former, such as glycerol, present in the gas-vapor mixture.