Pyrolysis of Tropical Agricultural Crop Waste (Pineapple Residue and Banana Pseudo-Stem): Kinetics, Mechanism and Valorization of Bio-Char

Abstract

Pineapple residue and banana pseudo-stem are waste from tropical agricultural production. Kinetics, thermodynamics, mechanism during pyrolysis of them and valorization of bio-char were explored. Both biomass decomposed rapidly at 150-500°C and there was a significant mass loss peak for banana pseudo-stem at 650 °C, which indicated that degree of lignification apparently affect pyrolysis characterization of biomass. Activation energy of pineapple residue and banana pseudo-stem was 159-292 and 169-321 kJ/mol based on multi-heating rate method. Whereas based on Gaussian multi-peak fitting method, derivative thermogravimetry (DTG) curves of pineapple residue and banana pseudo-stem were simulated with three or four fitting peaks, corresponding to decomposition of hemicellulose, cellulose and lignin and deep degradation. Interaction between these components intensified complexity of kinetic parameters. The main carbon number of organic volatiles during pyrolysis was C 4 and C 5 for pineapple residue, and that was C2 and C3 for banana pseudo-stem. High content of cellulose and hemicellulose in biomass (pineapple residue) intensified volatilization of volatiles. Porous carbon sourced from pineapple residue and banana pseudo-stems had specific capacitance of 375 F/g and 297 F/g at current density of 0.5 A/g, respectively. Pineapple residue and banana pseudo-stem were potential feedstock for electrochemical materials.