Biogas plants: how they are made and how they work

What are biogas plants?

Biogas plants are structures designed for the production of biogas through the anaerobic digestion process.

In these plants, organic material such as agricultural waste, food waste, and manure is decomposed by microorganisms in the absence of oxygen, thus producing biogas.

The biogas obtained is a mixture of methane (CH4) and carbon dioxide (CO2), with traces of other gases, and can be used for the production of electrical and thermal energy as well as fuel.

The main features of biogas plants are:

• the ability to handle a wide range of organic inputs
• efficiency in converting these materials into energy.

How are biogas plants made?

The operation of a biogas plant varies depending on its type and the type of biomass used.

A typical plant consists of several key components:

• a feeding system to introduce the organic material
• an anaerobic digester where the material is decomposed and biogas is produced
• a storage system for the produced biogas
• a unit for cleaning and using the gas.

The main function of these plants is to exploit the energy potential of organic waste, transforming it into a clean and renewable energy source.

But how does this process happen?

To proceed with the production of biogas, the material to be converted is stored in tanks, silos, or reservoirs, where it is pretreated and sterilized to remove any pathogens.

The substances are then transferred via special pumps and pipes into the digesters, where they are mixed with helical or hydraulic mixers. The gases thus accumulate in the upper part of the digesters, from where they are extracted and stored.

At this point, the gas is treated to remove impurities; this final step can be performed through various procedures:

• filtration through gravel and sand
• desulfurization
• removal of CO2
• cooling
• reduction of pollutant emissions

Once the process is completed, the biogas is transferred to the cogenerator, where it is used for the production of electrical and thermal energy.

Steel for biogas plants

Steel is the preferred material for the construction of biogas plants due to:

• corrosion resistance
• durability
• ease of maintenance

Stainless steel bolting elements are particularly suitable for these installations to ensure excellent sealing and long-term resistance, fundamental elements to maintain the efficiency and safety of the plant.

Advantages of biogas plants

Among the main advantages of biogas plants are the reduction of greenhouse gas emissions, thanks to the conversion of organic waste into energy, and the contribution to sustainable waste management.

Additionally, biogas production can provide an additional source of income for farms and contribute to energy diversification.

On the other hand, biogas plants require significant initial investments and careful management to ensure their operational efficiency, which constitutes the main disadvantage of their use.

These are indeed highly complex plants that require an accurate phase of analysis and design, taking into account various needs:

• maximize economic yield
• evaluate the quantity and distance of biomass sources
• minimize installation costs
• ensure compliance with workplace safety regulations
• minimize environmental impact.

In conclusion, biogas plants offer a promising solution for the production of renewable energy. Despite the challenges, their contribution to environmental sustainability and effective organic waste management makes them an increasingly viable energy option in the current context.

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