Physico-Mechanical Characterisation of Fuel Briquettes made from Blends of Corncob and Rice Husk

Abstract

Densification of agricultural residues such as husks, shells and cobs into fuel briquettes is an alternative renewable feedstock for producing solid fuels because it improves their physico-mechanical, storage and combustion properties. This paper presents the physico-mechanical characterisation of fuel briquettes made from blends of corncob and rice husk. The raw samples of corncob and rice husk were collected, sorted and pulverised. The pulverised samples were screened to 0.25, 1.0 and 1.75 mm particle sizes, blended at mixing ratios of 80:20, 70:30, 60:40, and 50:50, and afterwards, briquette samples were produced at 25, 50, and 65 kPa compaction pressures respectively with starch as the binder. The variations in the particle size, mixing ratio and compaction pressure have significantly influenced the investigated physico-mechanical properties of the produced briquettes. The briquette made from 80:20 mixing ratio of corncob to rice husk, 0.25 mm particle size and 65 kPa compaction pressure had the highest compressive strength of 111 kN/m2 and the least compressive strength of 39 kN/m2 from briquette with 50:50 ratio of corncob to rice husk, 1.75 mm particle size and 25 kPa compaction pressure. The briquette made from 50:50 mixing ratio of corncob to rice husk, 0.25 mm particle size and 65 kPa compaction pressure spent the longest time to collapse when immersed in water; taking up to 972 seconds and the least time of 480 seconds from briquette with 80:20 mixing ratio corncob to rice husk, 1.75 mm particle size and 25 kPa compaction pressure.