Effects of Process Parameters on the Density and Durability of Biomass Briquettes Made from Wet Method

Abstract
This work aimed at improving the density and durability of biomass briquettes made by composting and pressing biomass (wet method). Though this type of briquettes requires much less energy to form, they are usually of much lower density compared to briquettes made from dry biomass. In this experimental work three parameters were considered, which are type of biomass, composting time, and moisture content. Biomass samples were mixed with water and left to decompose for varying number of days. The moisture content of samples was conditioned accordingly and briquettes were made from these samples using a die and a pressing machine. Briquettes were tested for density and durability. Results show that among saw dust, groundnut shells and rice husk briquettes, rice husk briquettes attain highest density (up to 0.47g/cm3). For all three biomass types, durability index tend to increase with an increase in moisture content. Durability of groundnut shells and rice husk briquettes tend to decrease with an increase in composting time while that of saw dust increase with composting time. For all the three biomasses, the apparent density decreases with an increase in moisture content. For groundnut shells and rice husks the density increases with compositing time while for saw dust the change in density is negligible. In general it can be concluded that better and denser briquettes can be obtained by as long as possible composting time and as low as possible moisture content (but sufficient for bonds formation). However the lower moisture content will decrease durability. Also, saw dust is not recommended for wet briquettes unless long composting time is available. It can be recommended that briquettes which may be subjected to harsh handling and transportation be made using higher moisture content.
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Keywords
Biomass briquettes, Biomass composting, Wet briquetting, Briquette density, Briquette durability, Briquette testing
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