Rice Husk as a Source for Lightweight Flameless Heat-Energy Carbon Briquettes

Abstract

Herein we present a new method for producing fuel briquettes from rice husk, which can be used both individually or in combination. The designed briquettes are light-weighted and characterized by a flameless combustion that do not emit toxic substances during burning. These new briquettes were shaped from amorphous carbon obtained by carbonization of rice husks that was carried out in an inert atmosphere (N 2 /Ar) at the temperature 450 °C, followed by desilication using caustic soda for 2 hours and demineralization using nitric acid for 2 hours. To the thus obtained raw material, carboxymethyl cellulose (CMC) used as biobinder was added to form the briquettes and bind the carbon-based materials. In order to obtain briquettes of suitable hardness for all purposes ( ca. 30 MPa of briquette strength), 20% of biobinder was necessary. Oxygenating reagents (NaNO 3 and NH 4 NO 3 ) were also added to ensure high performant briquette flameless combustion. Based on the fact that these briquettes are mainly carbon-based materials with the containing 70-90% and therefore are characterized with a rather light overall weight during 30-38 g.