Effects of Mix Ratio on physical and combustion properties of a Novel Briquette of Sawdust and Banana Agro-Waste

Ogadis Jepkemei, David N Githinji, Charles Nzila, Saul Namango

Agricultural waste, briquettes, combustion, Mechanical, Physical.

Currently, there is a high demand for clean energy from renewable sources owing to their minimal environmental impacts. In Kenya, biomasses such as sawdust from sawmill industries and agro-wastes, such as banana leaves and pseudo stem, are potential sources of renewable energy. However, these biomasses are normally discarded in the fields and little information exists on their use as fuel in blended briquettes. Consequently, the current study investigates the use of carbonized sawdust and banana waste as raw materials for briquettes production. Specifically, the study aims at characterizing physical and combustion properties of blended briquettes produced from the two raw materials. In the study, pseudo-stem and banana leaves from Musa acuminata AAA species and sawdust from Eucalyptus tree species were collected, dried to 8 % moisture content, hammer milled, sieved and carbonized in muffle furnace at 400 ℃ for 5 minutes. Blended briquettes were produced at constant compaction pressure of 5 MPa at varying blend ratios (0:1 to 1:0) using molasses as a binder. The manufactured briquettes were then characterized in terms of mass density, durability index, ash content, moisture content, volatile matter and calorific value. From the characterization study of the raw materials: sawdust, banana waste and molasses had moisture contents of 12.52 %, 14.63 % and 22.23 %; volatile matter of 25.32 %, 31.45 % and 43.25 %; calorific value of 15.92 MJ/kg, 12.35 MJ/kg and 11.24 MJ/kg; ash content of 5.79 %, 6.89 % and 8.00 %, respectively. The determined mass density, calorific value and durability index of the blended briquettes increased with increase in ratios of sawdust while ash content, moisture content and carbon monoxide emission decreased. The density ranged from 392.54 kg/m³ to 681.21 kg/m³, calorific value from 23.40 MJ/kg to 25.92 kg/m³, ash content from 6.89 % to 5.79 %, moisture content from 11.10 % to 7.45 %,   durability index from 95.35 % to 99.70 % and carbon monoxide emission from 5.64 ppm to 1.74 ppm. The moisture content ranged from 6.65 % to 8.76 %, ash content from 5.82 % to 5.83 %, carbon monoxide emission from 4.58 ppm to 5.66 ppm, calorific value from 25.54 MJ/kg to 22.03 MJ/kg, density from 763.33 kg/m³ to 557.68 kg/m³ and durability index from 99.01 % to 96.52 %. From determined properties, the blended briquettes from carbonized sawdust and banana waste can be used as alternative source of fuel.

https://dx.doi.org/10.31873/IJEAS.10.02.04