Biogas i Vycia
Af Nicolaj Stenkjær, marts 2008.
Litauens Energistyrelse har skrevet nedenstående tekst om Folkecenterets teknologi transfer vedrørende biogas.
Se original teksten her.
The challenge of demonstrational biogas project in "Vycia" for rearrangement of pig farms
As to manure handling method, there was one exception in this 31-farm group. The farm in Širvintos, Central Lithuania, was build according to another concept of manure handling. This farm can be considered as precedent for biogas generation from organic waste in agriculture. The farm had been equipped with unique on Lithuanian scale concrete basins for aerobic treatment (biodegradation) of manure. As it appeared, this pioneer technology was too complicated and the facilities have remained inoperable. Later on the idea of anaerobic digestion was addressed to the basins as to bioreactors. In the autumn of 1994 a large biogas plant has been launched, using assistance and technology of a German company. The investments were extremely low because it was sufficient to cover the basin with PVC blankets only. Nevertheless, the manure from the stables was removed in hydraulic way, too, and was supplied to the basin highly diluted. The biogas was recovered, but due to blow danger and complication in supply of biogas to the boiler the process was stopped and not renewed. Lithuanian Agriculture Engineering Institute had intended to install a small experimental biogas plant and started to rearrange a railway cistern to digester tank, 60 m3 of volume. Nevertheless lack of finances and refusal of contractor - a neighbouring pig farm, suspended the elaboration. Now the institute has renewed its experiment in a small private farm, 200 sows with piglets. The results of biogas production are still poor, mainly due to inadequate technology.
In November 1998 the demonstrational biogas plant at a large pig farm was commissioned in "Vycia" company, Kaunas region. Initially it will operate on diluted manure. It will demonstrate the Danish technology transferred by Folkecenter for Renewable Energy. The plant is a gift of Danish Government (88 % of project cost), granted by Danish Environmental Agency.
In 1993 Folkecenter for Renewable Energy (director Preben Maegaard) suggested to Lithuanian Energy institute to find a suitable candidate as beneficiary for Danish biogas technology demonstration in Lithuania. One competitive pig farming company "Vycia" (director Kazys Cesnavicius), 10,000 pigs, was found. The institute has prepared the pre-feasibility study and application to Danish Government for a support in 1994. In subsequent, almost 2 years long the efforts of the institute and "Vycia" company were spent for getting the approval of Lithuania’s governmental institutions for a project. At the end of 1995 Danish Government finally approved the application. The tender for local manufacturer of steel methane tanks was arranged. The winner was company ICC (International Construction Corporation), from Mazeikiai town, North Lithuania. The manufacturing on site, as well as construction and assembling works were started in autumn, 1996 and were finished in 2 years. The ICC has installed 3 methane tanks, 3 mixing tanks, a boiler-house, a gasholder and piping system (see Figure 3). In 1997 the Folkecenter had opened its Energy office in Kaunas for supervision of demonstrational project and dissemination of renewable energy technologies in Lithuania.
The rated capacity of the biogas plant is assumed to be as follows:
- volume of methane tanks 900 m3
- daily manure input 50 – 60 m3
- daily biogas output 1200 - 3600 m3
- rated power capacity of cogeneration unit 1´ 75 kW and 1´ 110 kW;
- rated heating capacity of cogeneration unit 360 kW (100kW for plant’s own needs)
- rated capacity of heat boilers ("Tasso") 2 x300 kW
It is assumed that "Vycia" company could soon switch from electrical heating to biogas. The considerable cut in operational cost is expected to be gained. However, this gain is stipulated by the prerequisite of manure’s "dehydration". Only if dilution would be avoided, the project is likely to fulfil the demonstration of technological operability and efficiency.
Thus the demonstrational project, if succeeded, will be a challenge for a large pig-farming industry to rearrange the manure handling systems from hydraulic removal to non-diluting systems. The following dilution-preventive opportunities are envisaged for "Vycia" company:
To reduce waste water spilling from drinking, firstly, the small mechanical repair is needed for existing drinking devices. Secondly, the gradual replacement of old items by improved, efficiently water-saving ones is recommended.
The amount of sawdust for bedding the boxes could be reduced in some stables. It will result in less demand for clean water for sanitary cleaning of boxes and less demand for water for manure transportation from channels.
The waste water coming from slaughtering-house of the farm should not be allowed to dilute the manure coming from stables. Therefore the additional valves are recommended to be installed in slaughtering-house pipeline and collection tanks 4, 5 (Figure 2) and operated in special way. When waste water from slaughtering house is flushed down, it could be collected only in one tank. At this time the second tank with manure is closed by valve. The first tank will put out its content to sedimentation tank only, and second one will feed the biodigesters.
The collecting tanks, when feeding the biodigesters, afford a possibility to separate upper thin fraction from the settled thicker one. The upper fraction could be supplied to sedimentation tank, the lower one - to biodigesters.
Hence, the suitability of the sludge settled down in sedimentation tank is to be checked for biogas generation. The influence of sludge age on the biogas yield will be clarified in the initial period of operation.
Figure 3 The view of biogas plant “Vycia”
How to start with biogas projects in Lithuania
(recommendations for EU companies engaged in biogas business)
- Estimate a type of project that you offer (demonstrational, commercial). In case of demonstrational one you could get EU support. Small biogas units for a small farmer seems to be promising for demonstration status as there is no one operating unit on small scale.
- In case of commercial (profitable) project, the local partner could address for a subsidy or favourable loan the Energy Saving Fund (under control of Lithuanian Energy Agency), the Agriculture Support Fund, the Environmental Funds, municipalities.
- If local partner is ready to undertake the project risk, make jointly a good business plan. Electricity produced in cogeneration unit of your biogas plant will be purchased by national power company without barriers, according to the corresponding provision of Energy Law. Check your project’s risk by applying for a loan to a bank!
- What about demonstrational biogas plant operating on cow manure? There may exist no dilution problem in this case.
- Start a cooperation with Lithuanian large pig farm not directly from a biogas project but, firstly, from upgrading manure removal system. If a benefit would be gained, it will be encouraging to proceed with biogas.