Thermophysical property and single particle thermochemical conversion analysis of agro-residue pellets

Biomass, the CHO complex with typical energy content of ~ 18 MJ and having close to 50% by mass embedded carbon is expected to play a crucial role in decarbonization considering that every kg of biomass potentially fixes 1.8 kg of atmospheric CO ₂ . Agro-residue is a key contributor of phytomass with more than 50% of dry mass of crop being non-edible and hence available for energy extraction. Gasification is one of the key routes of agro residue utilization to generate a gaseous mixture consisting of H ₂ , CO, CH ₄ , CO ₂ and N ₂ . While for typical woody biomass (C _1.0 H _1.4 O _0.7 ) the gasification process parameters are well defined, densified agro residue in the form of pellets / briquettes which can potentially have varying thermo-physical properties are required to be analyzed for establishing the gasification process parameter bandwidth. The current article considers pellets from 5 different bio residues for investigation. The pellets are first subjected to proximate and ultimate analysis followed by single particle combustion analysis establishing the mass loss of the particle as a function of time as the particle is subjected to control thermal conditions along with a flux of gas phase reactants at a specific surface velocity. One of the key features emerging from the analysis is that normalized conversion profiles exhibited consistent trends across pellets, highlighting fundamental shared characteristics in combustion behavior. Further, particle density emerged as a pivotal factor impacting combustion. Higher pellet or briquette density correlated with lengthier combustion times, affecting combustion reaction kinetics.