Enhancement of gasification performance of Sesamum indicum stalk residue and Oryza sativa husk through densification and co-gasification with Prosopis juliflora

Abstract

Sustainable management approaches for crop residues have not been explored to their maximum potential. Most agricultural crop residues are arbitrarily burned in the agricultural fields, causing significant air pollution and health problems. This work investigated the gasification of two under-explored herbaceous agricultural wastes, namely Sesamum indicum stalk residue (SSR) and rice (Oryza sativa) husk (RH), in a throatless downdraft gasifier with air. It studied syngas composition, higher heating value (HHV), cold gas efficiency (CGE), and carbon conversion efficiency (CCE) at an air velocity of 7.5 m/s. To improve the gasification performance, pelletization and blending of woody biomass (co-gasification) were studied. After pelletization, the densities increased by 2.3 and 1.8 folds for SSR and RH, respectively. The CGE increased proportionately by 2.9 and 1.7 folds for SSR and RH, respectively. Meanwhile, CCE increased by 2.7 and 1.7 folds for SSR and RH, respectively. Further, the hardwood Prosopis juliflora (PJ) was blended with these biomasses in different mass ratios to improve their gasification performance. The co-gasification studies revealed that the gasification performance of the 1:1:2 blend pelletized SSR: pelletized RH: PJ matched that of hardwood. Thus, the results of this study demonstrated that the leftover agricultural biomasses could be efficiently blended with hardwood to produce energy and thereby (1) reduce hardwood consumption in gasification, (2) provide a solution to manage residues generated during agricultural practices, (3) contribute to a circular economy, and (4) complies with sustainable development goals 2, 7 and 12.