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Biogas Plants

A solution to generate renewable energy from organic wastes

Biogas is a renewable and versatile energy source that has attracted growing interest for its contribution to greenhouse gas emission reduction and sustainable energy supply.

Currently, there is concern about climate change, air quality and the dependence of many countries on energy imports. In this context, the installation of biogas plants is presented as an alternative to replace fossil fuels in the generation of heat, refrigeration and electricity. 

In Spain, the production and use of biogas is on an upward trend. Catalonia is the pioneering region in the valorization of biogas as an alternative energy source. According to various studies by gas companies, the production potential would be sufficient to cover up to 40% of the country's household demand.


How is biogas produced?

Chemically, biogas is a mixture of methane, carbon dioxide (CO2) and other compounds. It is generated from the controlled fermentation or microbial degradation of organic waste of plant or animal origin in the absence of oxygen. It is achieved through a decomposition process called anaerobic digestion

The raw materials used in a biogas plant, called organic substrates, can be solid food, crop residues, livestock manure or slurry and other wet organic wastes. The process is carried out as follows:

  1. This waste is mixed and placed in a biodigester or reactor (a closed container or tank in which organic matter is decomposed), where pumping systems facilitate the movement of fluids. 
  2. The organic matter is removed and heated to high temperatures to enable the biogas formation process.  It remains inside for several weeks before being transformed into a more stable organic product (digestate) and biogas. This is achieved through the action of different groups of bacteria.
  3. Both are evacuated separately through different outlet ducts.
  4. The gasometer is the structure that can store the biogas generated until it is used.

The methane resulting from anaerobic digestion can be used as thermal energy for various purposes. For example heating or electricity generation. It can also be used as biofuel for vehicles and as an input in industrial processes.

On the other hand, the liquid obtained from the degradation can be an organic fertilizer to improve degraded soils or to enhance crop growth.

Benefits of the installation of a biogas plant

A biogas plant or anaerobic digester can be installed in places such as farms, agricultural and livestock farms. It can also be located in wastewater treatment plants (WWTP), urban waste treatment plants or industrial facilities. 

ProCycla has extensive experience in the installation of biodigesters or biogas reactors in Spain and Chile. The technical capacity of our engineering team allows us to offer and implement any type of anaerobic digester. We have our own patented design.

In this way, we assist our customers in the treatment and revaluation of their organic waste at all stages. Starting with the feasibility study and all the legal formalities up to the start-up and maintenance of the biogas installation for the customer.

Among the advantages of installing a biogas plant we can highlight:

  • As it is a renewable energy, it benefits the environment, as it reduces pollution and helps to dispense with the consumption of fossil fuels thanks to the generation of thermal and electrical energy for self-consumption..
  • It represents a cost saving in transportation, storage and treatment of organic waste for companies, as it is an effective solution to manage them in existing infrastructures or facilities of various sizes and wealth can be created from them.
  • It allows obtaining high quality by-products (digestate) that are excellent as biofertilizers for agricultural crops, free of odors and pollutants. This organic fertilizer has a high content of nutrients that improve seed germination, strengthen roots and plant growth.
  • Through a process called upgrading (or biogas purification), by removing carbon dioxide (CO2) it is possible to generate biomethane, a gas that has the same composition as natural gas but has a higher energy potential. This biomethane can be injected into a domestic grid or sold as a fuel if produced in large quantities.
  • The methanol that can be extracted from biogas is also a feedstock for biodiesel production. It poses fewer environmental risks when used as a vehicle fuel, as it emits less nitrogen oxide, carbon monoxide and hydrocarbons than conventional gasoline or diesel. 

What type of waste can be used for biogas production?

Wastes that have demonstrated good performance in biogas generation include:

  • Agricultural residues: wheat, sugar and fodder beet, corn, grass, sunflower and rye grains. 
  • Livestock wastes (slurry) and slaughterhouse wastes
  • Dairy and cheese industry wastes
  • Municipal organic waste collected selectively
  • Waste from cannery packing houses
  • Remains from the fish processing industry
  • Wastes from the alcoholic beverage industry (stillage and grain after fermentation)