Comparative Analysis of Briquetting Most Viable Biomass Waste to Substitute Charcoal in Ethiopia
Creators: name: Belay, Anteneh
Publisher: name: National Academic Digital Repository of Ethiopia
Year: 2014

description: Agricultural residues seem to be the most promising energy resources for developing countries. However, the majority of them have low energy density. One of the favorable technologies for enhancing that property is charcoal Briquetting. A large amount of agricultural and solid wastes are left in the field after harvest. The primary objective of the study was to investigate the comparative analysis of resource availability, physico-chemical properties and performance of biomass charcoal produce from the most promising wastes. Specific objective were to develop and characterizing composite charcoal briquettes, investigate factors affecting densification of composite charcoal briquettes and compare resources availability, physic-chemical property and performance of charcoal briquettes with wood charcoal. The composite charcoal briquettes were produced using ASTM standard by a combination of process factors. The three process factors were dwell time, clay binder ratio and pressure. Design expert software, Box-Henken model were employed to investigate the effect of process factors. The Density was found in the range of 783.00-1,187.00 kg/m^3. The coefficient of multiple determinations for prediction of the proposed density model was about 95.7%. The effect of the three variables against density was investigated. When every two combinations of the above variables were increased, density of briquettes was also found to increase. Optimum point of dwell time, pressure and clay binder concentration was found at 3.6 minute, 45 bars and 18.27% respectively. The optimal point was validated. The Production of 1300 tones/yr briquettes plant was evaluated. The total investment cost was found to be 1.9137milloion birr. The net present value and the internal rate of return of the project were 2,753,976 Birr and 19% respectively it implies the project was feasible. Base on the resource estimation using production to residue ratio, the quantity of available agricultural residue, cotton stalk, coffee husk, bamboo residue and jatropha press cake in Ethiopia was approximately 4,655.887, 219.933, 109.757, 109.757,1,000 and 0.228Ktones/yr respectively. When the fixed carbon of charcoal made from bamboo, cotton stalk, coffee residue and composite with that of Acacia charcoal, 60.85, 58.4, 63.9, 68.25 and 69.74w/w % were found respectively. The above value all had relatively similar which makes it possible to substitute wood charcoal. Regarding heating values of briquettes produced from bamboo, cotton Comparative Analysis of Briquetting Most Viable Biomass Waste to Substitute Charcoal in Ethiopia AAU, AAiT, M.Sc. Thesis by Anteneh B. xiv stalk, coffee residue, composite and Acacia spp. charcoal were 29135.94KJ/Kg, 19209.03KJ/Kg, 11710.48KJ/Kg , 23446.08KJ/Kg and 32573.304 KJ/Kg respectively. But all the heat values of briquettes were lower than that of charcoal. If the country substitutes wood charcoal by charcoal briquettes, it will reduce 47.06 CH4 / year and 1530.383 Co2/year for every production of 1300 tons per year. The study showed that charcoal from bamboo; cotton stalk, coffee residue and agricultural residue could be used as substitutes for Acacia charcoal as they had comparable potential energy. But jatropha press cake currently had a low possibility to be use in our scenario. Generally, this research concludes that the biomass charcoal had positive value of production method, fixed carbon and performance, but one negative value was obtained from calorific value. With ¾ positive values, these biomass wastes can substitute wood charcoal in Ethiopia.