Browsing by Author "Tewodros, Walle (Mr.) Co-Advisor"

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    Comparative Experimental Investigation Between Parabolic Dish and Flat Plate Collector Based Solar Dryer for Saw Dust Briquette Production
    (Addis Ababa University, 2019-06) Hosaena, Alemayehu; Solomon, Teklemariam (PhD); Tewodros, Walle (Mr.) Co-Advisor
    From different types of briquette drying technology, the open sun drying system is the most widely used, which is found in many developing countries including Ethiopia. For this type of convectional drying process, the time required to remove moisture from the product is too long. In average it requires 3 to 4 days with available sufficient solar radiation. Beside that the recent improved type solar driers (flat plate-based driers) have still inefficiency regarding to the drying time. This happened due to the low drying air temperature effect that limits the drying time and efficiency. The main objective of this project was to design, construct and test more efficient solar drier compare to the recent developed dryer type. To prove the new type of drier performance, the experiment has been done by comparing the performance of the parabolic dish based drier (PDSCD) with the Flat plate based drier (FPSCD). The comparative assessment has been done with scientific experiment using different measuring methods and tools discussed in this paper. The experiment was conducted in the Addis Ababa Institutes of Technology compound free field area for both solar driers. The drying air temperature has been increased using concentrator collectors. The PDSCD and FPSCD absorber surface temperature, drying air temperature, air speed at the outlet of the drying chamber, moisture content variation, the relative humidity at ambient and inside the drying chamber were measured with unloaded and loaded setup using direct and indirect measuring methods. The amount of moisture removed from the drying chamber of PDSCD and FPSCD is 0.039 kg and 0.022 Kg respectively. The measured result indicates that performance PDSCD has a better moisture removing capacity rate than FPSCD. After analysis of the measured result, the thermal efficiency parabolic dish collector and Flat plate collector is determined 31.55% and 8.95 % respectively. And the overall drying system efficiency of the PDSCD and FPSCD is 31.55 % and 8.95 % respectively where the PDSCD has better performance than FPSCD.
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    Process Optimization for Biodiesel Production from Trichiliaemetica Seed ‘Luiya’ Oil
    (Addis Ababa University, 2018-07) Seid, Shumet; Solomon, Kiros (PhD); Tewodros, Walle (Mr.) Co-Advisor
    The Energy utilization in the whole world has achieved by using the natural resource like coal, natural gas and petroleum diesel for a long period of time. Continuous using up of those nonrenewable energy sources leads to running down the reserve. In addition to this environmental problems are the main issue in the whole world and this leads to search more attractive and environmentally friend energy source. From this biodiesel is the best one to replace petroleum diesel in order to fulfill our energy needs for a sustainable way. The high cost of edible oil seed has increase biodiesel making price. Due to this searching non-edible oil seed has to minimize biodiesel making cost. The major objective for this study work was the optimization process for making biodiesel from the trichiliaemetica oilseed. For transesterification process trichiliaemetica oil, methanol alcohol and calcium oxide catalyst were used. Extraction of oil was undertaken by using manually operated mechanical compress and 75 ml/kg oil was extract. Experimental results of trichiliaemetica oil properties are moisture content (0.43%), density (910 kg/m 3 ), kinematic viscosity at 40 o C (36.4 cSt), saponification value (183.7mgKOH/g oil) and acid value (4.628 mgKOH/g oil). similarly, the experimental result for characterization of biodiesel from trichiliaemetica oil was listed like: density (887 kg/m 3 ), viscosity at 40 o C (6.11cSt), flashpoint (129 o C), acid value (0.897mgKOH/g oil) and higher heating value (39.8MJ/kg). The physicochemical properties of trichiliaemetica oil and produced biodiesel were matched with the standard values. Moreover, the design expert software was the tool and implemented five level four-factor central composite designs with response surface methodology to optimize the process. Four process parameter was studied with the range: time (1-2hr), catalyst (1-2 weight %), methanol/oil molar ratio (6:1-12:1) and temperature (55-65 o C). The optimum trichiliaemetica oil conversion was achieved at the time (1.5hr), calcium oxide catalyst (1.5 weight %), methanol/oil molar ratio (9:1) and temperature (60 o C). From the analysis of variance result, the experimental percentage of biodiesel yield was 94% and predicted the percentage of biodiesel yield 90.75%. In addition, the result from response surface methodology all parameters except time rendered the high significant influence for biodiesel yield. From the present study, the results show that process optimization from trichiliaemetica oil seed is essential for industrialization and expansion for production of biodiesel.