Grape pomace as an energy source for the food industry: A thermochemical and kinetic analysis

The present study investigated the thermochemical performance of grape juice processing byproducts, namely grape pomace grits, grape pomace powder, grape seeds, and grape seed powder, using differential thermogravimetric analysis to determine kinetic parameters during thermal decomposition. Pyrolysis experiments were carried out at heating rates of 10, 20, and 30 degrees C to a maximum temperature of 700 degrees C. The mean activation energy for grape pomace powder of 29.96 kJ/mol was the most energy efficient pyrolysis among the four byproduct types. Physicochemical characterization confirmed that these pulp residues can serve as a potential feedstock for fuel and energy production. Grape seeds had a higher lignin content (49 and 52% for seeds and powder) than grape pomace (38 and 45% for grits and powder), making them an appropriate raw material for industrial applications, particularly chemical production. Moreover, their relatively high cellulose and hemicellulose contents indicate a high saccharification potential. The proposed thermal conversion technique could be used downstream from the conventional biodigesters to convert the digestates of juice processing byproducts to biochar and bioenergy. The key findings of this study target growth of sustainable circular economy in the food industry. (C) 2022 Institution of Chemical Engineers. Published by Elsevier Ltd. All rights reserved.

Automated summary

This study investigated the thermal decomposition kinetics of grape juice processing byproducts using differential thermogravimetric analysis. The results showed that grape pomace powder had the lowest activation energy and the highest energy efficiency, making it suitable for pyrolysis. Physicochemical characterization confirmed the potential of these pulp residues as feedstock for fuel and energy production. Grape seeds were found to have a higher lignin content and a relatively high cellulose and hemicellulose content, indicating their suitability for industrial applications and high saccharification potential. The proposed thermal conversion technique can convert the digestates of juice processing byproducts to biochar and bioenergy.