What is biomethane?
Biomethane is similar to natural gas, as it is a pipeline-quality product. In order to upgrade biogas to biomethane, you need a biogas upgrading plant, which is what produces the biomethane. In addition, since it is a pipeline-quality product, the biomethane produced is similar to natural gas. Due to its similarity, it is also a better alternative to fossil fuels as it is carbon dioxide neutral, making it better for the environment. This makes it ideal to be used as a transport fuel, as it can be injected into the natural gas grid or turned into a compressed natural gas.
What is biogas upgrading?
A biogas upgrader is a facility that is used to concentrate the methane in biogas to natural gas standards, which therefore produces biomethane. This process is also known as biogas purification, and it is a more appealing alternative than using a heat and power system (CHP).
The process entails separating methane from carbon dioxide and other gases and contaminants from biogas. Concentrated biogas is known as ‘biomethane’ or ‘renewable natural gas’ (RNG), and the resulting biomethane can then be used for vehicle fuel or injection into the natural gas grid network.
How long does it take to produce biogas?
The amount of time spent producing biogas varies. Plants that produce biogas for use as fuel will speed up the decomposition process artificially by using an anaerobic digestion project. This process can take 30 days to complete in a less controlled environment. For example, landfill biogas production can take considerably longer.
This is because it is harder to produce an oxygen-free environment in a landfill. Therefore, before methane production can take place, aerobic bacteria must use up the oxygen within the waste. On average, this process can take 1 year to complete, then once it’s completed, methane production can commence. As landfills are outside, ambient conditions can affect the deoxygenation rate and how long the methane production takes. For instance, cold and dry climates will slow the process down; whereas, warm and humid conditions will accelerate the decomposition.
Why monitor and analyse the gas?
Biomethane is a biogas which has been upgraded to a quality similar to fossil natural gas and has a methane concentration of 90% or greater, which is used for vehicle fuel or injection into the natural gas grid network.
In a natural gas network, the grid entry unit governs the flow of gas into the network and will require the gas quality to be of a sufficient level for entry, typically over 95% methane. The verification of the scrubbing process for the removal of H2S and the overall purification process all need to be monitored through the analysis of the composition of the gas.
Benefits of biogas
- Eco-friendly – it’s a renewable source of energy so your business will be decreasing its carbon footprint, by emitting fewer greenhouse gases.
- Reduces soil and water pollution – biogas generation can improve water and soil quality, as anaerobic digestion deactivates pathogens and parasites.
- Low-cost technology – the technology used to produce biogas is relatively cheap.