Biogas and biomethane gain greater acceptance
Biogas is a wonderfully flexible and renewable form of energy and can be used as a building block to make not only a wide variety of liquid fuels, but also organic chemicals and even plastics.
The biogas digestion process (anaerobic digestion) can be installed and run at the household level with simple training and support, and can also be developed into large projects to make community and district anaerobic digestion plants. These can take up to 100,000 tons per year of organic waste and create methane from it.
When the methane produced is cleaned and compressed, it is called biomethane and can be pumped into district networks that today deliver natural gas to us from fossil fuels.
A home biogas plant consists of a tank (at its simplest, just an underground brick pit) where manure (human sanitary waste) and other organic materials are mixed with water and allowed to ferment.
A farm biogas plant does the same thing but in a larger reactor and usually takes slurry from farm animals, but in some Scandinavian plants it can also use silage. The silage is stored to feed the farm’s biogas plants during the long, cold winters, when other organic feedstocks may be in short supply. The agricultural anaerobic digestion (AD) plant can thus strengthen the ability of agricultural enterprises to withstand bad weather and bad years when harvests are poor, and its adoption in large numbers will therefore improve the resilience of the agricultural sector.
Let us not forget either that a greater production of biogas and its use will result in a reduction in greenhouse gas emissions and large plants will be able to make reductions of the order of 50,000 tons of CO2 equivalent per year.
An AD plant always contains two main components: a digester (or fermentation tank) and a gas reservoir. The digester in the most common types of plants is a sealed rectangular or cylindrical container with an inlet into which the fermentable mixture is introduced in the form of liquid slurry.
China is an example of a nation where the government has introduced a biogas program. More and more governments realize that biogas production not only benefits the ecological system, but also benefits rural populations. India and Nepal are also well known for their digesters.
The benefits are many and include being an alternative energy source, methane is very useful for cooking, improving rural sanitation, reducing firewood consumption, easing the burden on rural women, providing a liquid fertilizer for fields and being a mud that can improve the soil. quality, more more. Furthermore, each farmer can also earn a cash income from this.
The actual results of biogas programs have shown that these real benefits improve rural life in many ways.
In one example, the biogas digester attached to the toilets provides cooking gas for a 600-student school and vocational training program run by the foundation. In the past, non-governmental organizations were the only ones offering these ideas, but that is rapidly changing as the good news spreads.
Once fermentation in an AD plant is complete, the biogas exits the top of the digester at a low pressure, sufficient to overcome losses and provide enough pressure to push the gas through a gas burner and, Similarly, through some power generation engines. without any compressor to increase pressure.
Countries in Europe are now beginning to sit back and take stock of the successes in China and other nations, and are introducing new legislation to encourage the adoption of AD technology. These laws will be explained and discussed at length in both plenary sessions and workshops at a surprisingly large number of conferences this year.