In this folder are present the CHEMKIN format files. The mechanism is labelled polymer_Nspecies_Nreactions. For instance PET_85_700 is the mechanism with 85 species and 700 reactions. The mechanism proposed for PET are:
- PET_85_700 the published mechanism
- PET_18_19 a "global" model with significantly lower computational cost.
The thermodynamic properties have not been investigated due to lack of data and theoretical approaches for aromatic esters.
To cite the semi-detailed mechanism refer to the following publication:
- Locaspi, Andrea et al. "A lumped kinetic model and experimental investigation of Poly(Ethylene Terephthalate) condensed-phase pyrolysis", Chemical Engineering Journal 500 (2024): 156955. DOI
To cite the multistep mechanism refer to:
- Locaspi, Andrea et al. "A multi-step condensed-phase kinetic model for poly(ethylene terephthalate) thermal degradation", Proceedings of the Combustion institute, under review
For all mechanisms, only the amorphous polymer is considered currently. The starting polymer is described in the semi-detailed mechanism by "P-COPhCO-P" and "P-OCCO-P", which represent the terephthalic and glycol moieties of the amorphous polymer (present in equimolar ratios). For the multistep mechanism, both units are represented by the "P-PET-P" species. Both mechanisms consider a single condensed pseudo-phase and model char as liquid-phase species. Mechanisms considering two condensed phases can be provided upon request. Compared to the mechanisms for the other polymers, phase-change is considered separatedly and not pseudo-reaction is introduced. In OpenSMOKE++, polymer and char species species must be defined in gas-phase as well, but do not have physical meaning.
In each folder are present the standard CHEMKIN files (gas kinetics, liquid kinetics, thermodynamics, transport) and a sub-folder of LiquidProperties. The latter is required by OpenSMOKE but reports only FAKE liquid properties of all the chemical species included in the mechanism. These are required for the 1D microgravity model available in OpenSMOKE, but they have not yet been addressed for polymers outside of 0D systems.
All mechanisms are validated with ~50 of data from the scientific literature. Here are reported few validation comparisons in terms of parity plots of mass-loss profiles and gas-phase yields. In-depth discussion of the discrepancies between semi-detailed model and experimental data are provided in the semi-detailed paper (Locaspi (2024)), while the deviations of the multistep model with respect to the semi-detailed one are discussed in the latter paper (under revision currently).
MAH = Mono Aromatic Hydrocarbons, BA = Benzoic Acid, VB = Vinyl Benzoate, TA = Terephthalic Acid, MVT = Monovinyl Terephthalate, DVT = Divinyl Terephthalate