Energy Technology

Permanent URI for this collection

http://etd.aau.edu.et/handle/123456789/51

Browse

Browsing Energy Technology by Subject "Biogas"

Now showing 1 - 2 of 2
  • No Thumbnail Available
    Item
    Biogas System Planning for Rural Households Based on Energy Demand (The Case of Holeta District)
    (Addis Ababa University, 2017) Mesfin, Debebe; Abubeker, Yimam (PhD)
    This research is conducted to study the energy consumption trend and to make easy of planning the biogas system design which can helps to meet the energy demand of the rural households found in Holeta district. The energy demand of the households is assessed based on the questionnaire paper. The information of the assessed households is collected randomly from different family sizes that live in “Geda Jogo” and “Ada odo” Villages. Households are using electricity mostly for lighting purpose. Fire wood, Charcoal and dung cake are the main sources of energy to meet the cooking Energy demand. The average amount of annual fertilizer consumption by the peasant households is 220 kg. Spreadsheet modeling tool is prepared and it is used to estimate Households biogas demand, gas production potential of the households and Digester volume including the expected Loading rate. It is also used to forecast the basics of Economical aspects which should be known before the plant is designed. To crosscheck the proper functionality of the spreadsheet modeling tool Manual calculations has been performed for the average and peak values observed in the surveyed households and compared with the values found from the spreadsheet model. For the average values, the Biogas demand, the gas generating potential of the Households and digester volume observed in the spreadsheet calculation tool are 6.001m 3 /day, 6.8 m 3 / day and 20.3949 m 3 respectively. The values gained using manual calculations are 6.114m 3 /day, 6.8m 3 /day and 20.4 m i 3 . For the peak values calculation in spreadsheet modeling tool, the Biogas demand, the gas generating potential of the Households and the digester volume needed are 9.19m 3 /day, 8.8 m 3 / day and 26.3934 m 3 respectively. Where as in the manual calculation the values are 9.16 m 3 /day, and the digester volume is . Priority rank on the households energy demand has been performed, so that it will help on the biogas system design. The economical aspect of the biogas system is also included and how the households could be benefited using this technology. The estimated cost to construct the plant for the average values are ETB 29,840 with a payback period of 3 years. The cost spent to buy chemical fertilizer could be saved. Finally the benefit cost ratio is calculated to be 1.44 which is greater than 1.
  • No Thumbnail Available
    Item
    Optimization of Biogas Production From Slaughterhouse Waste and Digester Sizing: A Case in Addis Ababa Abattoirs Enterprise
    (Addis Ababa University, 2016-07) Tsegaye, Genet; Asefa, Birhanu (PhD)
    This study focuses on production of biogas from slaughter house waste to generate optimal methane yield. Which has high calorific value under Optimum temperature, pH and substrate proportion (blood, manure and undigested stomach content). And also Digester Design for dumping waste of AAAE. In this study first experiment was carried out to determine pH, total solid, volatile solid and ash content of each type of waste fermented independently at optimal temperature (350c) and at pH 7. Second experiment was by mixing three type of wastes based on crossed D-Optimal design expert software which had 42 run at different proportion of substrate Blood and Manure at range of (10%-20%)’ undigested stomach content at range of (60%-80%) , pH range (4-10) and temperature at range of (20oc-45oc). After the experiment the following parameters: methane content, caloric value or energy generation capacity and volume of biogas, pH, temperature, total solid, volatile solids, and Ash content of each type of waste were determined. From individual type of 350ml sample waste (blood, manure and undigested stomach content) Maximum Biogas production and methane composition was 0, 7lit, 4lit and 0%, 66% and 54% respectively. From 42 run experimental result by crossed D-Optimal Design Expert software the best optimal methane composition and biogas production was 79.26% and 0.381lit/gm of VS respectively. Optimal condition was 20% blood, 20% manure and 60% undigested stomach content substrate composition, at pH=7.88 and temperature 32.49oc. 79.26%CH4 composition has a potential 7.88kwh per m3 of Biogas. The amount of biogas produce from AAAE waste is2968m3/day which has a potential to generate 23,393.4kwh/day of energy. 3,148.8 kwh/day apply to facilitate anaerobic digestion activity and remaining 17, 207.9kwh/day for steam generation. Which can cover for 70.7% of boiler furnace oil and gas oil consumption and save7, 087,740.ETB birr/year of its budget. This study has shown that application of biogas plant for AAAE is financially, environmentally and socially feasible. The cost benefit analysis shows that NPV is positive and benefit cost ratio is 2.03 which is greater than the proposed value for application of given project. As the financial analysis shows after implementation of this project AAAE can annually save Birr 6,006,520. Which can be invested to construct four digester plants having a volume of 753.75m3 with daily 120.6m3 total feedstock fed to the digesters. At optimal mixture of three waste and optimal condition. Key words- Digester, Biogas, Methane, slaughterhouse waste, anaerobic digestion