Techno-environmental assessment of the fuel properties of a variety of briquettes for biomass boiler applications

Abstract

This study evaluates the fuel properties of five briquette samples made of Saw Dust (SD), Cocoa Shell (CS), Corn Cob (CC), Palm Kernell Shell (PKS) and Coconut Husk (CH), blended with starch at 50 % binder ratio to assess their suitability as boiler fuels, addressing the need to transition to cleaner, more efficient and sustainable boiler fuels for effective decarbonization of the heat and power sector of industry in Ghana. Pertinent solid fuel properties were measured to characterize fuel performance ranges. Environmental implications were also assessed through emissions measurements. SD emerges with the lowest relaxation ratio (1.39), indicating superior stability during transportation. CC exhibits the highest HHV (25.22 MJ/kg), while CH (187 g/h) demonstrates superior fuel economy. CH (27.93 %wt.) presents higher igniting potential, while CC and PKS may necessitate combustion-enhancing additives for ignition. CC (12.34 ± 2.25 wt. %) yields lesser ash, potentially enhancing boiler performance and guaranteeing minimum maintenance as compared with the other briquette samples. Four-day average measurements reveal minimal CO₂ and CO emissions for all samples, indicating negligible environmental threat. PM2.5 emissions mostly conform to WHO safety thresholds, albeit SD exceeding the recommended limit. The diversity of desirable fuel properties obtained, barring the few anomalies observed, demonstrate that briquettes hold the key to achieving fuel resource, environmental, and performance sustainability so far as boilers are concerned. The results also serve as pointers for further research to consolidate knowledge on more detailed fuel performance characteristics.