Abstract
Estimation of molecular sizes of hydrocarbons in tyre-derived oil (TDO) is necessary for selecting an oil upgrading catalyst. Generally, the size of a hydrocarbon mixture can be described using average kinetic and maximum diameters. Due to molecular movement, average kinetic diameter (Øk) is absolutely needed. However, maximum diameter (Øm), defined as the longest part of a molecule, can ensure that all molecules in the mixture can pass through the catalyst pore. Therefore, the objectives were to estimate average kinetic (Øk,avg) and and average maximum (Øm,avg) of hydrocarbons in TDOs, and then suggest selective catalysts to handle them, aiming to decrease heavy fraction especially aromatic compounds and increase lighter products. Øk was calculated using critical parameters from Joback method, whereas Øm was estimated using published data from Chemspider. More than 800 species detected by GCxGC- TOF/MS were classified into saturated hydrocarbons (SATs), olefins (OLEs), naphthenes (NAPs), terpenes (TERs), mono-aromatics (MAHs), di-aromatics (DAHs), poly-aromatics (PAHs), and polar- aromatics (PPAHs). As a result, the Øk,avg of all hydrocarbon groups is in the range of 6.5 - 8.1 Å. The Øm,avg of SATs and OLEs is 8.1 - 34.7 Å, whereas that of the other groups is in the range of 6.6 - 14.6 Å. Hence, in order to handle aromatic groups (6.6 - 14.6 Å), aluminophosphate catalysts (6 - 15 Å) or mesoporous materials such as MCM (20-30 Å) families are recommended.
