Effect of hot water extraction on pyrolysis of tender coconut fruit biomass: kinetic and thermodynamic parameters

Effect of pre-treatment of tender coconut fruit bio-mass powder with hot water on physico-chemical properties and thermal degradation behavior were investigated. The physico-chemical parameters were evaluated using ASTM standard protocols. The thermal degradation behavior was studied at heating rates of 10, 15 and 20^oC/min under inert (N₂) atmospheric conditions using TG/DTG techniques. The activation energies at each heating rate were determined using Flynn-Wall-Ozawa (FWO), Kissinger-Akahira-Sunose (KAS), Starink, and Tang models. The pre-treatment with hot water improved the proximate and ultimate analyses parameters and calorific value. The higher heating values (HHV) for untreated and treated tender coconut fruit biomass were 18.57 and 21.26 kJ/kg, respectively. The values of activation energy (E_α) for the un-treated biomass powder were estimated to be 389.25, 397.81 and 398.77 and 397.97kJ/mol for FWO, KAS, Tang, and Starink models, respectively and for the treated biomass these were 125.43, 118.61, 118.99 and 118.94kJ/mol, respectively. On an average the E_α of the treated coconut biomass was nearly three times lower than that for the untreated biomass. The results indicated that pre-treatment with hot water improved the fuel characteristics and thermal degradation behavior of the tender coconut shell biomass. The water extract exhibited high COD and BOD values and might be used as the feed-stock for biogas generation. Graphical abstract: [Figure not available: see fulltext.]