Do-it-yourself biogas plant for home heating
In some countries, biogas production accounts for a large share of their energy sector. For example, in Thailand it is a national program. And there already up to 25% of the total energy consumption is covered from gas obtained from biological solid waste. And the volumes of receipt are only growing:
Warm climate, agricultural country - all conditions for the introduction of this natural technology. Natural - because biogas (composed of methane (60%), carbon dioxide (30-40%)), produce methane bacteria during anoxic (anaerobic) process of their life. And in Thailand, this technology is used by both small farms and large biogas plants.
Is it possible to use this technology here, in our climate? In the summer - 100% is possible, even in a barrel. But in winter, you need to take into account the temperature regime for the container. The temperature inside must be at least 20 grams.
After watching a number of videos on youtube, I highlighted one channel of a villager who installed a simple scheme for generating biogas and uses it for his own needs. I suggest looking at:
Video 2016
This is an introduction to the principle of gas production. There are many other videos on this topic on his channel. Anyone interested - look. Well, for now, I will briefly tell you in numbers about his experience and results.
It produces biogas in clean 200 l drums. Places in them in the volume of 2/3 of the barrel, chicken manure diluted in water. From a week to a month, CO2 comes out, and then methane starts to come out. From one barrel per day, it pumps biogas into a 50-liter propane cylinder with a compressor in such a volume that a pressure of 8 atm is created in it. One atmosphere from this cylinder is enough for 14 minutes of gas stove operation (with redesigned injectors). This is briefly. He has several such barrels in his back room. Gas from the barrel can be released from 6 months to a year and, after being cleaned in artisanal filters, it accumulates in car chambers (pumped under its own low pressure).
To remove CO2, the author uses a slaked lime filter. More expensive components can also be used. The second filter is a polyethylene pipe with stainless steel shavings (to remove hydrogen sulfide). I don't know what chemical reaction is used. Ideally, you also need a gas dryer. For example, from silica gel (used in sewage treatment plants). Read more about this in the author's videos.
In order for the gas output to be larger and longer, it is periodically necessary to stir the contents of the barrel. The video below shows an example diagram of how this can be done:
Those. it turns out, having a small subsidiary farm (for example, chickens, pigs) from their manure, you can fully provide your village house with gas for cooking. What about heating?
There are such safe gas convectors on sale. The exhaust gases are removed to the outside. The gas supply can also be carried out along the outer wall. Tell me - is it dangerous? Yes, biogas burns, but it is not as explosive as a propane-butane mixture. Biogas contains a large amount of carbon dioxide. But, despite this, the heat of combustion is very high:
During combustion, 1 m3 of biogas provides the same amount of thermal energy as: 3.5 kg of firewood, 1-2 kg of coal or 9-10 kW / h of electricity
They can also power an electric generator. You only need gas equipment for it, adjusted to a certain pressure. But biogas needs to be cleaned of moisture. We need filters. Also a solvable problem (there is an example of a solution to the issue on the channel above).
Compost after working off is the best fertilizer in the garden (increases productivity). This is another plus. What to do in winter? In order for the bacteria to produce methane, positive temperatures are needed, preferably 30-50 grams. To do this, at a depth below the freezing depth, it is necessary to arrange containers for such bioreactors. See how one man from Armenia did:
Wells made of concrete rings, hermetically covered with metal lids.
According to this project, it was planned to heat the entire village. But the project stalled. Gas needs to be bred to homes. Therefore, only the author uses it so far.
I will not argue that this scheme will work in Siberia, with a soil freezing depth of 2.5 m. Perhaps this is only suitable for the Black Sea regions in our country, where there is practically no winter. But in temperate or cold climates, you can use the method in the spring-summer-autumn period. Manure is still fertilizer. And so it will bring considerable benefit. In addition, many cunning officials began to rip off levies from farmers: allegedly for causing harm to the environment (methane emissions into the atmosphere and water pollution). This method will avoid such problems and unnecessary costs:
This article is just an idea for those who are a villager, a farmer and keep a backyard with various livestock and animals. Do you have enough biogas to heat your house - the question! You need to count and come to the numbers empirically. Less biogas is produced in winter. The compost or manure heap must be insulated. Although it warms itself (especially with manure), the temperature is still not summer. But if you put barrels with manure inside a poultry house or other structure, it can definitely be heated with biogas.
Security issue. A gas that has a smell is added to the propane-butane mixture. Nobody installs gas analyzers with alarms. In vain. A simple, reliable and inexpensive system can be developed and recommended to be installed at every point of gas consumption.
And for biogas, you can purchase gas analyzers for methane:
How the issue of interaction with gas services is resolved is a question for them. I don't think they can prohibit the use of the compost pit. The main thing is not for sale, only for your own needs.
Conclusion: as said, this is a working idea for heating a house or other facilities for farmers, farms in villages, who keep large and small livestock. At least - a gas source for a gas stove. It is quite possible to become even more independent from external energy sources. It is also a thought for poultry farms and large farms. But there are many other, bureaucratic issues arising: coordination of the installation in the authorities.
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Photos are taken from open sources, from Yandex. Pictures
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