Abstract:
Conventional or non-renewable sources of energy are very limited and depleting very rapidly. Biomass is any type of organic renewable materials which contain energy in a chemical form and converted to fuel, accordingly sesame stalk biomass briquetting is one of the important alternative sources of renewable energy. This study investigates the development and characterization of briquette from sesame stalk and waste paper as binder for production of fuel briquettes.
The sesame stalk was harvested, cleaned, sun-dried, and milled using hammer mill. The raw sesame stalk was characterized by the following properties: moisture content (3.63%), fixed carbon (17.50%), volatile matter (72.82%) and ash content (6.05%).
Briquettes were produced by mixing carbonized sesame stalk with waste paper in weight percentage ratios of 90:10, 80:20, 70:30, 60:40 and 50:50 at three different average particle sizes of sesame stalk (1, 3 and 5mm). Within the context of briquetting, binding agents are added to comminuted carbonized biomass feed stocks to improve the combustibility of the resulting briquettes. From the experiment the results of all sesame stalk briquettes fall in the range of bulk density (526.21-535.62Kg/m3), shatter resistance (88.02-89.07%), volatile matter (64.0169.20%), ash content (10.46-14.25%) and calorific value (25.167-28.00MJ/Kg).
The maximum blend of sesame stalk particle size and waste paper percentage was assessed on the basis of the briquette properties: The combination of 5mm average particle size of sesame stalk and 10% waste paper percentage gave the optimal volatile matter of 69.20%, ash content 10.46% and calorific value 28.00MJ/kg. As binder percentage increases and the particle size of the sesame stalk decreases exposes more contact surface area, bonding, inter particle interaction, compact and leading to a small number of pore spaces, while the large sizes of particles have a large number of pore spaces. Due to this, the flow of oxygen within the interparticle of the briquette will be limited.
Generally the laboratory analysis showed that the calorific values of briquettes obtained were enough to produce energy content for combustion. Therefore sesame stalk briquettes can be a very good alternative source of energy compared to rice husk, groundnut shell and sawdust
viii
briquettes. As a result of substituting 40% consumption of petcoke of Dashen cement factory with sesame stalk fuel briquette can reduce about 2,410 tons of CO2 per year emitted from combustion of fossil fuel petcoke.
From the analysis of economic feasibility, the investment cost for plant modification for 40% biomass fuel switching would be approximately Birr 16.7 million. The investment cost could, therefore, be recovered in less than one year from savings in the fuels cost alone