Evaluation of Thermal and Emission Performances of Briquettes Produced from Carbonized Corn Cob and Corn Husk

Abstract

The Mozambican agro-industrial sector relies heavily on various crops, with maize being the most significant. During processing, substantial waste is generated, which is often discarded as organic matter or burned, contributing to environmental pollution and the loss of potential energy resources. This study evaluated the thermal and emission performance of briquettes made from carbonized corn cob (CCC) and carbonized corn husk (CCH), using cashew nut skin as a binder for clean cooking applications. The briquettes were assessed against firewood and charcoal as control fuels, focusing on several energy performance parameters: water boiling time (WBT), combustion index (CI), thermal efficiency (TE), and emissions (E). Testing was conducted using an improved combustion stove (burnjikokoa). Results indicated a CI of 1.06±0.04 for carbonized corn cob briquettes (BCCCNS) and 1.14±0.03 for carbonized corn husk briquettes (BCHCNS). The WBTs (in minutes) were 17 for BCCCNS, 29 for BCHCNS, and 45 for both firewood and charcoal. Thermal efficiency was notably higher for BCCCNS (45%) and BCHCNS (42%) compared to charcoal (24.13%) and firewood (21.55%), suggesting that the selected waste materials are excellent for producing highenergy briquettes. In terms of emissions, particulate matter (PM2.5) levels were measured at 80 µg/m³ for both BCCCNS and BCHCNS, while firewood produced 190 µg/m³ and charcoal 120 µg/m³. Carbon monoxide (CO) levels were all below 200 ppm. These findings demonstrate the potential of utilizing agro-industrial waste to create sustainable and efficient cooking fuels.