Design and fabrication of an improved low-cost biomass briquetting system for rural communities

Abstract

This study was designed to develop a portable briquette mould to produce briquette and evaluated the performance of the briquette mould for household use in rural settings. Briquette mould was developed using engineering principles that satisfy the requirement of appropriate technology for rural dwellers. The biomass used for briquette production was Cordia millenii, and cow dung as a binder. The sawdust from Cordia millenii was screened to a particle size of 2 mm, washed with water, and mixed with cow dung at binder ratios of 15, 25, and 40% by mass. The briquette mould was developed to be used in a press that was already constructed to provide low compaction pressure of 5 MPa. The physical, mechanical, and combustion characteristics of the briquettes such as water penetration index, compressed density, relaxed density, durability and burn rate were measured to evaluate the performance of the Briquette mould. The mould has a volumetric capacity of 1.76 x 10⁶ mm³, and a production capacity of 7.35 Kg/hr. operating at a pressure of 2.5 MPa. Briquettes of the size 150 mm in diameter and 55 mm in height were produced. The result of the tests showed that the relaxed density ranged from 0.36 to 0.38 g/cm³. The binder ratio had a significant impact on the relaxed density of the briquette. The durability varied from 56.81 to 68.85 %, with the 25 % binder ratio having the highest value. The calorific value varied from 27.84 to 28.01 MJKg^-1, increasing as the binder ratio increased.