Biogas Cogeneration and Biomethane Upgrading
What is Biogas
Biogas is one of the most used alternative renewable energy’s sources. It derives from fermentation of organic substances (animal or vegetable) by numerous bacteria, in the absence of oxygen and at a controlled temperature. The biomass degradation process is called: anaerobic digestion.
Biogas is generally composed in 45 to 70% of methane and the remainder of carbon dioxide (other substances suche as carbon monoxide, nitrogen, hydrogen, hydrogen sulphide are present in a lower percentage).
The biogas has a high calorific value and the outgoing digestate, which appears as a liquid product, can be used as a natural fertilizer in crops.
The biogas can be used and exploited in different ways: from the biomethane production to cogeneration for the production of electrical and thermal energy, and for the heat production.
Cogeneration is the process used for the simultaneous production of electrical and thermal energy. It consists of an Otto cycle engine fueled by biogas coupled to a synchronous alternator complete with electronic control system and automatic combustion regulation for emission control.
Biogas has a high calorific value and can be converted into electricity and heat. The heat can be used for heating buildings and for industrial production processes.
The excess thermal energy produced can be reused for the production of cold through the absorption system (absorption chiller), thus giving rise to the “tri-generation” as well as CCHP, Combined Cooling Heating and Power.
What biomethane is
Biomethane is natural and renewable methane gas, derived from the purification process (upgrading) of biogas (mixture of methane and carbon dioxide) obtained from the enhancement of products and by-products of the agricultural and industrial chain.
The biomethane can be fed into the network like methane from fossil sources, it can be used as CNG (Compressed Natural Gas) or LNG (Liquefied Natural Gas) for the transport sector, and CO₂ can also be extracted from its purification and be reused in industrial and / or food production processes.
Like natural gas (fossil methane), biomethane can: