Combustion Characteristics of Briquettes of Different Feed-Stock of Agricultural Wastes a Review

Biomass utilization through briquette technology has been used extensively with a number of agricultural feedstocks. Despite having energy policies and implementation framework in some countries like Nigeria regarding biomass waste utilization, some agricultural wastes still remain unexploited nor characterized. This review paper embraced journals mainly from Google scholar published between 2006 and 2025, to establish properties and characteristics of various agricultural wastes and emerging trends. For the agricultural wastes characterized in this paper, the proximate analysis results showed, the average moisture content as 8.48 %, volatile matter 56.91 %, ash content 8.94 % and fixed carbon 24.42 %. These quantities were well within the recommended ranges, showing opportunities for utilization in briquette making. Limited amount of nitrogen and Sulphur content, that is below 1 % and 0.3 % respectively and absence of the same in some feedstocks was observed too. This encourages their utilization since nitrogen and Sulphur are the agents of pollution and being low, provides best substitutes for fossil fuels which have been main donors of the same to the environment. Carbon and hydrogen content averages for these feedstocks were 43.19 % and 5.94 % respectively. This having an influence on fuel combustion, the quantities portrayed, gives an assent for utilization of such feedstock for briquettes making. Average calorific value for briquettes from covered feedstocks was 18796.95 kJ/kg. Thermogravimetric analysis revealed high burning rates at high temperatures with increase in heating rate. Increase in amount of binder, negatively affect calorific values. Highly compacted briquettes result to low combustion rate, but good briquettes in terms of storage and transportation. More research needs to be carried out on other agricultural wastes to add to the available feedstock for briquettes. Further, there’s need to adopt modelling and artificial intelligence which is underutilized in characterization and study of properties of this agricultural biomass.