Bioenergy generation and value addition from processing plant-generated industrial tea waste: a thermochemical approach.

This study deals with the solid waste management in tea processing industries by thermochemical conversion of the raw or industrial tea waste (ITW) for bioenergy generation and value addition. The elemental carbon (C) in ITW was 43.35%. Moreover, ITW exhibited gross calorific value (GCV) of 43.35% and 19.48 MJ/kg, which was comparable to firewood species. ITW was subjected to pyrolysis and industrial tea waste biochar (ITWBC) and industrial tea waste bio-oil (ITWB) were obtained as the main products. The pyrolysis increased the elemental C content and GCV in ITWBC up to 80.01 wt% and 24.00 MJ kg⁻¹, respectively. Besides, alkane, alcohol, phenol, nitro, and aromatic compounds were obtained during spectroscopic analysis of ITWBC. The fixed carbon (FC) content increased from 22.50 to 74% after the conversion of ITW to ITWBC. The H/C and O/C ratios (in weight) decreased after the thermochemical conversion of ITW to ITWBC and ITWB. ITWB is comprised of 66.21% of C; the major components were phenolic (84.6%). Moreover, aromatics, esters, ethers, ketones, alcohols, furans, and aliphatic components were also identified during spectroscopic analysis of the ITWB. The spectroscopic analyses suggest effective thermochemical conversion of ITW with the involvement of chemical processes such as polymerization, dehydration, decarboxylation, aromatization, intermolecular condensations, and rearrangements. The study highlights the possibility of waste management in tea industries via integrated biorefinery approach, besides further validating the potential of ITW for energy/fuel production and value-added product development under the realm of "Waste to Wealth" technology. [ABSTRACT FROM AUTHOR]