Emission Characteristics during Combustion of Torrefied PET-Biomass Composite Pellets

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Ukrit Samaksaman
Rattanaporn Punthurat
Chanyud Kritsunankul
Kanit Manatura
Kittikorn Sasujit
Sirinuch Chindaraksa


Most of polyethylene terephthalate (PET) bottles, though, has been taken into a recycling system, it still has some problems after preparation and the mechanical process. Waste of PET from the mechanical process is useless and non-recyclable. Pelletizing of such PET waste with biomass such as teak sawdust (TS), eucalyptus sawdust (ES), and corncob (CC) were investigated. Torrefaction of PET-biomass composite pellets was manipulated after pelletizing. Proximate and ultimate analysis as well as the high heating value were deployed to analysis. Moreover, emission characteristics during the combustion of samples of non-torrefied and torrefied pellets; PET/TS, PET/ES, and PET/CC were studied in a lab-scale fixed bed reactor. Emission of flue gas (O2, CO2, CO, SO2, and NOx) and gaseous pollutants (polycyclic aromatic hydrocarbons; PAHs and aromatic hydrocarbons such as benzene, toluene, ethylbenzene, and xylene; BTEX) were determined. The results indicated that flue gases such as CO2, CO and NOx were decreased in the samples of torrefied pellets. SO2 could not be detected due to no sulfur content of the origin materials. The torrefied PET/TS and PET/ES pellets could reduce PAHs compared to the nontorrefied samples indicated as 0.07 and 0.03 g/Nm3, respectively. While emissions of BTEX could not be detected in samples of torrefied PET/TS and PET/ES. Combustion of the torrefied PET/CC pellets caused emissions of PAHs and BTEX with the total concentrations of 6.45 and 0.01 g/Nm3, respectively. Therefore, the torrefaction was a suitable pretreatment method for
PET-biomass composite pellets and altered emission characteristics during the combustion.


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