Biogas energy

Biogas energy

1. Jordan University of Science and Technology Mechanical Engineering Department RENEWABLE ENERGY SYSTEMS (ME 720) Students : Mutaz Al- Deiry Tareq Al-Anbar Hussam Al- Omri Mohammed Al- Sbahen Instructor: Professor Ghassan M. Tashtoush

2. Outlines Definition Components of a waste treatment biogas plant The Biogas process Process parameter for biogas plant The major applications of biogas plant Design digester of biogas plant Case study Conclusion 1 2 3 4 5 6 7 8 1 2 3 4 5 6 7 8

3. History F irst determined in 17th century that flammable gases could evolve from decaying organic matter . The first digestion plant was built at a leper colony in Bombay, India in 1859 . In the 1930s, studying and researches was to identify anaerobic bacteria and the conditions that promote methane production.

4. Definition Biogas is a renewable energy source . Biogas is the mixture of gases produced by the breakdown of organic matter in the absence of oxygen, usually consisting of certain quantities of methane and other constituents. Biogas can be produced from raw materials such as agricultural waste, manure, municipal waste, plant material, sewage, green waste or food waste. 1 1

5. Biogas is a combustible mixture of gases. It consists mainly of methane (CH4) and carbon dioxide (CO2) and is formed from the anaerobic bacterial decomposition of organic compounds, i.e. without oxygen . Table (1): Composition of biogas Definition 1 1

6. Fig.(1) :Energy yield for possible feedstock.

7. Components of waste treatment biogas plant Feedstock Air collection system Bio filters Digester Gas tight storage Gas cleaning system Separate storage Storage 2 2

8. The biogas process Biogas production is obtained by anaerobic decomposition (absence of oxygen) of biomass in the presence of bacteria. The bacterial decomposition of biomass takes place in three phases, namely hydrolysis phase, acid phase and methane phase. 3 3

9. Fig.(2): The anaerobic decomposition of organic matter consists of three main phases. The biogas process 3 3

10. Process parameters for a biogas plant 1) Temperature : Temperature is one of the most crucial factors in biogas generation. The rate of biochemical processes generally increases with temperature . 2) Anaerobic environment: The methanogens need an oxygen-free environment – they are obligate anaerobic . 3) Acidity (pH): The optimum environment is a pH of between 6.5 and 8, and the preferred level is 7.2. 4 4

11. The major applications of biogas plant Lighting Fig.(3): Major application 5 5 Cooking power generation

12. Design Digester of Biogas plant Biogas digester is any structure that converts organic material (waste) into energy in the absence of oxygen . Various materials and geometric configuration have been used for the design of biogas digester system. 6 6

13. A ir-supported outer membrane R adial blower I nner membrane L evel sensor O utlet-side pressure flap A nchoring profiles O verpressure/vacuum protection C oncrete foundation 1 2 3 4 5 6 7 8 Biogas D igester C omponents 6.1 6.1

14. Biogas D igester S izing The volumes of the digesters were calculated from the following equations: Where : = volume of the digester in cubic meters : amount of substrate in kilograms = retention time in days   6.2 6.2

15. Biogas production was calculated using equation: G = V s x G y Where : Vs = weight of feedstock available per day in kilograms Gy = Gas yield in cubic meters G = biogas production in cubic meters Biogas D igester S izing 6.2 6.2

16. Gas production rate was calculated using equation: Gp = G / Where: = gas production rate in cubic meters per day. G = biogas production in cubic meters. = digester volume in cubic meters.   Biogas D igester S izing 6.2 6.2

17. Biomass is the major source of domestic energy for both rural and urban areas in Uganda . This translates to million tones of round wood for firewood and charcoal per year. About 92% of ugandas energy demands are satisfied by wood and charcoal which caused loss of 27 % of the total forest and tree cover in the last 15 years. Case study 7 7

18. The energy obtained from waste materials like plants , animals and humans is what is referred to as biomass energy . Here we have the composition of the bioga s.

19. The calorific value of biogas is approximately 20MJ/m^3. Methane is responsible for the energy obtained from the biogas depending on the biological process and type of biomaterial. An average dairy caw produces about 55 Kg of solid waste per day, which adds to 20 metric tons of dung per annum, around 3 kwh of electricity could be generated daily from the dung and urine of just one caw. Unmanaged livestock waste can create negative environmental impact ( air pollution and ground water contamination). The methane created through anaerobic digestion of manure has proven to be 21 times more damaging than carbon dioxide, aggravating to climate change .

20. The ideal temperature for methane producing bacteria is about 35 C. Low temperature reduces gas production and nearly stops at 10 C. Plants built underground tend to have stable temperatures within daily allowable fluctuations of 1 C and in our site the minimum is 17 C. The time required for the organic matter to be digested in the digester is called the retention time and its temperature dependent, the higher the temperature the faster the bacteria use the food in the slurry and the sooner it needs replacement. Suitable solid content ( dry matter concentration ) is 7-9 %.

21. Design 7.1 7.1

22. At a cost of 2000$ and 4-6 herds of a cattle , a family of 5-8 people can acquire a biogas plant to meet their daily cooking and lighting energy for between 20 to 30 years, the average of 10 cows is adequate. The fixed dome type biogas plant was chosen because of low cost and cheap technology. The size of the plant digester volume was determined to be 6 m^3. The major economic activity of the rural populace in this study area is cattle keeping and subsistence farming which provide disposal system for the by-product of biogas plant in form of fertilizer. The situation on the ground warrants the implementation of a biogas energy initiative as the major domestic energy for cooking and lighting. Conclusion 8 8

23. Thank you Any Questions?