Co-pyrolysis of Cotton Stalk and Cooked Food Waste for Production of Enhanced Biodiesel Range Compounds

The present study aimed at enhancing the formation of fatty acid alkyl esters (FAAE)-the biodiesel-range compounds via co-pyrolysis of cooked food waste (CFW) and cotton stalk (CS). The co-pyrolysis experiments were conducted at fixed temperature and heating rate, but with varying carrier gas (N2) flow rate and mixing ratios. The temperature and heating rate were maintained at 500 oC and 50 oC/min, whereas the N2 flow rate was varied from 5 to 10 LPM and mixing ration were varied from 10 (CFW):90(RH) to 90 (CFW):10(RH). The results showed that increasing fraction of CFW in co-feed to pyrolysis at a particular flow rate, not only enhanced the FAAE formation, but also enhanced formation of separate phase for FAAE with up to 98% its fraction. However, on changing the flow rate to higher value, the separate phase formed only beyond mixing ratio of 50:50. The highest FAAE yield was obtained at the same mixing ratio and at 7.5 LPM carrier gas flow rate. Finally, the unravelling of reaction mechanism highlights the formation of FAAE via gas phase esterification reaction between intermediates formed via decomposition of non-lignocellulosic and lignocellulosic part of lipid-rich biomass like CS and CFW.