Combustion of pellets produced from corn straw and cashew nut shell in residential and industrial scenarios: Chemical, thermal and emission analyses.

Abstract

The Brazilian Northeast region has considerable agricultural potential for corn and cashew nuts production. Residues from these cultures can be densified into pellets and used as heat generators in industries and homes. In this study, corn straw pellets (CSP) and cashew nut shells pellets (CNSP) were handmade, together with a variation using glycerol as a binder (CSGP and CNSGP). All pellets were subjected to chemical, thermal and exhaust gas analyses of their combustion. All analyses were based on two different scenarios: (i) the use of CSP and CSGP for energy supply in residential use and (ii) the use of CNSP and CNSGP for energy supply in industrial use. All pellets were subjected to chemical, thermal and exhaust gas analyses of their combustion. Chemical analysis involved the study of various fuel properties, comprehending moisture content (%U), bulk density (kg m-3), volatile materials (%V), ash content (%C) and fixed carbon (%FC), and all evaluated pellets met two or more international trading standards. The combustion process analyses in the residential scenario showed higher average temperatures and lower carbon monoxide (CO) and nitrogen oxide (NOx) concentrations obtained during CSP combustion than those of CSGP, and in the industrial scenario showed average similar temperatures and lower CO and NOx concentrations obtained during CNSP combustion than those of CNSGP. Ours results demonstrate the great potential of corn straw and cashew nut shells as crops to be integrated into the biomass supply chain for energy generation and agro-ecological development.