Plastic biogas digester technology

Transcription

1 HydroBioPower: livelihood improvement in rural area through collaborative development of renewable energy sources in Oromiaand SNNPR States of Ethiopia i This project is co funded by European Commission Plastic biogas digester technology Stefano Stirpe March 2011 NAIROBI

2 Plastic biogas digester technology Biogas is a gas produced from fermentation of organic materials. It is a flammable gas and could be burned for any heating purpose (such as cooking), for lighting or to be converted into electric energy. To be produced it requires: 1. Organicmaterials: i animal ldung 2. A proper amount of water 3. A digester, that is a tank where fermentation happens and biogas is produced

3 The scheme of the plastic biogas digester

4 Type of Biogas Digester There are different designs of biogas plants Semi continuous Floating Fixed Dome Plug flow/polyethylene Batch Type Digester Yearly feeding Hard and solid type of substrate

5 Comparison (Plastic bag and fixed dome) Disadvantage of fixed dome High cost of the digesters Difficulty in installing them Difficulty in procuring spare parts Advantages of fixed dome Durable Good pressure of gas Sufficient gas production Polyethylene Polyethylene l Exposed to external cheap and simple Damage age It is appealing to rural HHD Low gas pressure small scale farmers low cost

6 Polyethylene Biogas (History) Initially introduced in Taiwan as red mud Started testing in 1980s in Ethiopia( ENEC /T. Preston) Later simplified by T. Preston in Ethiopia Recommended din 2003 by BTG (EREDPC) 11 Polyethylene digesters were imported from Holland (Laminated) Five of them installed around Debre Ziet Two of them survived and the rests are damaged due to poor lamination Low cost bio digester technology Aiming at reducing installation cost

7 Polyethylene biogas (History) Locally Produced at Blue Nile Factory 10 Polyethylene Biogas Digester Installed Some of them survived more than six month The rest were damaged due to external problems 1.5 m 3 of gas consumed within 24hrs Sufficient gas production No reservoirs installed Poor quality

8 Problems Encountered External Damage Rodent animals Cats Hyenas Domestic animals Human Trench Rims collapsing in black cotton soil Lack of storage facility

9 Conclusions \ Designing of proper & cheap protection Inverted v shaped iron angle/wood frame protection barbed with chicken wire Partially mason work on rim trench h(black cotton soil) Inclusion of reservoir is mandatory

10 Trench preparation Proper Siteselection ti As much as possible close to the kitchen Far from shade and tree roots Possibly not far from cattle barn Gentle slope Bricks making & Trench preparation Constructing the mud bricks on the ream of the trench Make the bottom of the trench with 2.5% slop gradient

11 Preparation of PBD Cut the plastic from the role for the digester (11m) and the reservoir (3m) length. Insert the plastic tube in to the other one so as to make double film Make a proper hole on the plastic digester so as to connect with gas pipe line. A simple plastic pipe connects the top of the digester to another polyethylene bag used for gas storage.

12 Main parts of the digester (1) BIOGAS OUTLET SUBSTRATE INLET SUBSTRATE INLET: Through this pipe takes place the insertion of the feeding (cow dung and water). BIOGAS OUTLET: Through this pipe the gas yield flows out of the digester.

13 Main parts of the digester (2) SLURRY OUTLET SLURRY PITS SLURRY OUTLET: Through this pipe, automatically the exhausted substrate (slurry) comes out. SLUTTY PITS: The slurry is accumulated here and by means of appropriate handling it can be obtained compost

14 Biogas pipeline and safety valve Biogas pipeline The biogas pipeline carries biogas from the bio digester to the stove inside the kitchen. It passes through the biogas safety valve, the digester valve and the stove valve. FROM DIGESTER TO KITCHEN Biogas safety valve It prevents the pressure in the scheme from going above safety level. A little hole is created in the bottle and used to set the proper safety level of water.

15 Digester valve This is the valve which regulates biogas flow from digester to reservoir. It is placed along the pipeline, between the biogas safety valve and the reservoir.

16 Reservoir and pressure system RESERVOIR: This is the plastic tubular where the biogas, coming from digester, is stored in wait for exploitation. CANVAS PRESSURE SYSTEM: This is realized by means of a CANVAS and four plastic bottles (LOAD BOTTLES) filled with soil. It is required in order to give the proper pressure to LOAD O S biogas during stove working. BOTTLES

17 Stove valve This is the valve which regulates biogas flow to the stove. It is placed alongthe pipe line, justbefore the stove.

18 Stove and cooking Stove This is the device which allows to burn the biogas and cook.

19 Inverted V shape protection roof This is the external protection structure of the digester. It needs in order to avoid the damage to the digester from domestic and wild animals and etc.

20 Slurry utilization Can be used as organic fertilizer Can be applied directly in to crops The slurry facilitates the prepartion of compost with in short period of time and increase the ammount of organic fertilizer to be produced.

21 To be installed and managed the plastic biogas digester required: 1. A daily amount of cow dung and water for feeding. 2. Ownership of 3 4 cattle and proximity to a water source ensures the capacity to feed the scheme.

22 HydroBioPower: livelihood improvement in rural area through collaborative development of renewable energy sources in Oromia and SNNP Regional States of Ethiopia Achievements: The Energy Facility Project 45 scheme constructed in the pilot phase in three intervention districts together with government bodies to test the adaption of the technology The pilot schemes evaluated and accepted by government to scale up to 940 schemes Up to now 76 schemes constructed successfully Training given to government staff (for 46 experts) at all stage about the technology 13 SMEs trained to take part in the scale up of the technology All necessary process by now finalized to start the scale up phase like tender for BG scheme construction, purchasing process for the main components like tubular plastic and stove, and users selection

23 HydroBioPower: livelihood improvement in rural area through collaborative development of renewable energy sources in Oromia and SNNP Regional States of Ethiopia Achievements The development of different manuals like construction manual, operational and maintenance manual and user manual in addition to specific training and capacity building for the users as well as for partners and government experts. By tapping biogas in a biogas plant and using it as a source of energy, harmful effects of methane on the biosphere are reduced. d Keeping waste material and dung in a confined place can minimise surface and groundwater contamination as well as toxic effects on human population. By conversion of waste material and dung into a more convenient and high value fertiliser ( bio slurry ), organic matter is more readily available for agricultural purposes, thus protecting soils from depletion and erosion. Generally the low cost plastic bag digester was found to be one of the alternative energy sources especially for poor farmers. The daily gas production is found sufficient for cooking.

24 HydroBioPower: livelihood improvement in rural area through collaborative development of renewable energy sources in Oromia and SNNP Regional States of Ethiopia Successes: Strong linkage and cooperation with sector offices of local government. Sound operation system and methods as well its organizational learning andadaptive nature. Strong commitment and dedication of grassroots organizations, stakeholders, technical staff and users Problems encountered during implementation were timely rectified and working methods were continually refined and updated to incorporate lessons that were learned. Most of the materials used for the construction of the schemes are available locally and affordable by the users

25 HydroBioPower: livelihood improvement in rural area through collaborative development of renewable energy sources in Oromia and SNNP Regional States of Ethiopia Challenges: Water: The substrate of most digesters needs to be mixed with an equal amount of water. During the dry season in semi arid places this can lead to an additional burden for the plant operator. Therefore it is not recommendable to build a digester if the nearest permanent water source is more than 30 minutes away. Dung: In manyplaces cattle arenot kept in stables tbl and are, at least for part the day, free roaming. As dung collection will not practiced with families who keep free roaming cattle, this new activity might be seen as an inconvenience. Problem of soil character which h is notsuitable for trench making since it slides easily by itself and not stable for bricks construction. On time delivery of some factory material like plastic take quite long time since only limited companies involved in this sector with quality capacity Cultural barriers like low utilization of the slurry because of fear of health risk during managing the slurry and also not willing to incorporate the human wastes

26 HydroBioPower: livelihood improvement in rural area through collaborative development of renewable energy sources in Oromia and SNNP Regional States of Ethiopia Lessons learned: The energy saving aspect and thus saving on cost for firewood is from the point of view of the farmer household h an important aspect. Moreover it is on of the major considerations of a government to promote this technology because it reduces the burden on the environment. It saves trees and helps thereby to combat erosion and to store carbon (reduction of green house gasses). The general impression is that cooking onbiogassaves saves time because it eases the need to collect firewood. On the other hand extra time is needed to feed the installation daily and to carry out other maintenance like cleaning the burners orletting outcondense water fromthe gas pipe. If the installation is badly located or if other circumstances are unfavourable (e.g. difficult to find water and/or feed material), the burden of collecting firewood is just replaced dby another strenuous activity. ii

27 HydroBioPower: livelihood improvement in rural area through collaborative development of renewable energy sources in Oromia and SNNP Regional States of Ethiopia Lessons learned: Cooking on biogas has also a significant health advantage over traditional cooking with an open fire. The major point is the fact that cooking is smokeless and that will diminish the number of eye infections and respiratory problems among in particular women usually in charge of cooking and small children being near their mothers. Also the danger that children burn themselves while cooking is less when using a biogas stove. The BG promotion should be integrated with other developmental programmes so that it could promote sustainable human development, linked with quantitative as well as qualitative growth of the local people, leading to their empowerment, and in the process would also become a marketable commodity to sustain its own growth.

28 HydroBioPower: livelihood improvement in rural area through collaborative development of renewable energy sources in Oromia and SNNP Regional States of Ethiopia This project is co-funded by European Commission Thank you for the kind attention!