Valorization of textile sludge and tannery fleshing wastes through co-hydrous pyrolysis within the domain of biocrude production

The conventional energy supply system is often seen as unsustainable so transitioning to waste-to-energy is a growing trend. This study investigated co-hydrous pyrolysis (co-HP) of textile sludge (TS) and tannery fleshing wastes (TFW) at varying TS:TFW ratios (1:0, 3:1, 1:1, 1:3, and 0:1) for biocrude production. The maximum 38.31% biocrude yield obtained was from 1:1 ratio biomass with an energy recovery of 70.43% and the highest carbon recovery of 57.9%. The highest 33 MJ kg⁻¹ of energy value was found for 3:1 biocrude. The FTIR and GC–MS analysis confirmed that the co-HP biocrude had superior hydrocarbons (5.86%), esters (32.35%), and fatty acids (19.07%) with no sulfur, silicon, and phenolic-based compounds. The percentage of short-chain (C₅–C₁₂) carbon was found higher in biocrude. The specific gravity of biocrude was found in the range of 0.83 to 1.15, and co-HP biocrudes were extra heavy to heavy type fuel. The biocrude was predicted using FTIR to a similar compound of methyl octyl dichlorosilane that supports wastewater treatment. The individual TS-derived biocrude contained a 23% silicon-based chemical compound that might be used as a defoamer in textile effluent treatment plants. The Van Krevelen diagram showed that co-HP biocrude had more energy potential than distinct HP biocrude. The lowest energy consumption ratio was found 0.62 for a 1:1 ratio biocrude suggesting that co-HP was an energetically feasible process. The maximum 6.64 bbls Mt⁻¹ biocrude could be produced through the 1:3 ratio waste biomass, generating $524.46 that validates the sustainability of the co-HP process.