Effect of process parameters and feedstocks on selected briquette properties

Abstract

Energy availability at the domestic level continues to pose a challenge worldwide, especially in Africa. Densification of biomass into briquettes has been considered as a substitute altemative fuel. Briquettes based on two feedstocks have shown improved characteristics; however, knowledge about the effect of briquettes with more than two feedstocks and best mix ratios is not thoroughly studied. The broad objective of this study was to assess the effect of process parameters and agricultural wastes (rice husk- maize cobs and bagasse) as feedstocks on selected briquette properties at different mix ratios (1:1:1, 1:212, 1:313, 2:1:2, 2:213, 2:3:l, 311:3, 3:211 and 3:312) after carbonization using a drum kiln. Then char was milled to less than 2mm, blended, and mixed with molasses binder for densification and agglomeration. The perfonnance characteristics (using Water Boiling Test in a “jiko okoa” cookstove) including ignition time, time to boil, buming rate, specific fuel consumption, and power output were determined. A mixture of 111:1 was used for the three, screw press, drum and hand agglomeration for briquettes production. The high density (screw press) briquettes which had better characteristics were used to determine their physical and combustion properties at selected feedstocks mix ratios. Taguchi- based Grey Relational Analysis was used to determine optimal condition for briquettes which was attained at mix ratio of 3:221 using the screw press technique. Physical properties of briquettes; moisture content and density were 6.43% and 904 kg/m3 respectively. Combustion characteristics of these optimal briquettes were 3.63% ash content, 18.56% volatile matter, 77.81% fixed carbon and 29.04 M]/kg calorific value. The quality of briquettes was influenced by technique and mix ratios. These research findings are of importance to briquettes users as a source of clean energy and environment conservation thus realization of Sustainable Development Goal (SDGs #7).