What is a biogas plant Types process advantages and disadvantages

A biogas plant is a facility that produces biogas, a renewable energy source, through the anaerobic digestion of organic materials. Anaerobic digestion is a biological process that breaks down organic matter in the absence of oxygen, producing biogas as a byproduct. Biogas primarily consists of methane (CH4) and carbon dioxide (CO2), along with small amounts of other gases.

1. BIOGAS PLANT

2. Biogas plant Biogas plant is an airtight container that facilitates fermentation of material under anaerobic condition Anaerobic digestion of organic matter producesa mixyure of methane (CH 4 ) and carbon dioxide (CO 2 ) gas. The material which is used in biogas plant for producing biogas called Biomass. Forms of biomass listed below may be used along with water Animal dung, Poultry waste, Plant wastes, human excreta, Industrial waste , Domestic waste.

3. Properties of Biogas Biogas is a mixture of different components and the composition varies depending upon the characteristics of feed materials, amount of degradation, etc. Biogas predominantly consists of 50 to 70 per cent methane, 30 to 40 per cent carbon dioxide and low amount of other gases. Methane is a combustible gas. The energy content of biogas depends on the amount of methane it contains. Methane content varies from about 50 percent to 70 percent.

4. Biogas composition Methane CH4 : 55-70% Carbon dioxide CO2 : 25-40% Nitrogen N2 :0-2% Hydrogen Sulphide H2S :0-3% Hydrogen H2 :0-2% Oxygen O2 :0-2%

5. Components Of Biogas Plant Digester or fermentation chamber Gas holder or gas storage chamber Inlet (pipe or tank) Outlet (pipe or tank) Mixing tank Gas outlet pipe Inlet and outlet displacement chambers Plant dome or arched roof Inlet and outlet gates Manhole or digester cover

6. Factors affecting the biogas production pH (6.5 – 7.5) C:N ratio (30:1) Temperature (30-35 °C) Loading rate Size of the material used Retention time (30-55 days) Seeding Uniform feeding Diameter to depth ratio (0.66:1) Water to input material mixing ratio (1:1) Total solid content of the feed materials (8-10 %) Nutrients Type of feed stocks Effect of Toxic substances Proper mixing/stirring of content in the digester

7. Microbiology of biogas production The production of biogas from organic material under anaerobic condition involves sequence of microbial reactions. During the process complex organic molecule present in the biomass are broken down to sugar, alcohols, pesticides and amino acids by acid producing bacteria. The resultant products are then used to produce methane by another category of bacteria. The biogas production process involves three stages namely: i . Hydrolysis ii. Acid formation and iii. Methane formation

8. Classification Biogas Plant Community biogas plants Institutional biogas plants Family size biogas plants This type of biogas plants are installed at individual family level.  The biogas from this type of biogas plants are used by the individual family.  The size of these plants is recommended up to 6 m 3   per day. These types of biogas plants are installed by an institution such as religious institution like Gurudwara / Mandir /Gowshala or educational institution like School/College. The biogas produced from these plants is used for the respective institution.  The size of these plants is recommended also to be more than 15 m 3  per day. It is a plant to be used by a group of people as a community.  These types of plants are installed by a Village Panchayat /Municipal Committee for any Village/ Mohalla /Town/City. The biogas produced from this type of plant is distributed to the people living in that locality. The size of theses plants is recommended to be more than 15 m 3  per day.  

9. Conventional models There are two basic models of biogas plants popular in India: 1. Floating-drum type model biogas plants - KVIC model 2. Fixed-dome type   model biogas plants - Janta Model Biogas Plants , Deenbandhu Model Biogas Plants

10. Advantages of biogas Disadvantages of biogas Biogas is eco-friendly. Provide employment by biogas plant. Biogas generation produces organic fertilizer. It is simple and low cost technology. It reduce greenhouse effect . Biogas is not attractive in large scale. Few technology advancement Contains impurity Less suitable for dense metropolitan

11. Reference https://slideplayer.com/slide/17101653/ https://www.homebiogas.com/blog/what-is-a-biogas-plant-and-how-does-it-work/#:~:text=A%20biogas%20plant%20is%20a%20facility%20that%20provides%20oxygen%2Dfree,positive%20effects%20on%20the%20environment . http://ecoursesonline.iasri.res.in/mod/page/view.php?id=1432

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