Research on the interaction mechanism between textile dyeing sludge and biomass components during high-temperature co-pyrolysis

An in-depth analysis of the interaction mechanism between biomass components and sludge underpins effectively recovering energy by co-pyrolysis. The impacts of biomass component interactions with textile dyeing sludge (TDS) on the thermogravimetric property, pyrolysis reaction kinetics, and product formation routes were investigated. The interaction is most powerful when the adding ratio of biomass components is 20 wt%. The actual reaction activation energies of co-pyrolysis of TDS with cellulose, hemicellulose, and lignin were 53 %, 38 %, and 13 % lower than the predicted values, respectively. The co-heating of TDS with cellulose, hemicellulose, and lignin could be described by the “bubble”, “attenuation”, and “fusion” processes. Co-pyrolysis of TDS and cellulose/hemicellulose increases the total content of H2 and CO by 3 %∼10 % while reducing the CO2 content by up to 7 %. TDS may catalyze the rearrangement and cycloaddition of oxygen-containing heterocyclic rings and monocyclic aromatic hydrocarbons derived from cellulose and hemicellulose, producing polycyclic aromatic hydrocarbons such as indene, naphthalene, and phenanthrene. TDS-lignin interaction promotes the dehydroxylation, decarboxylation, and demethoxylation of phenolic compounds, producing aromatic compounds. Furthermore, C–C deformation and C–H fracture were stimulated, boosting the production of H2. This research advances the understanding of the interaction mechanism between TDS and biomass components during the high-temperature co-pyrolysis process.