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Biogas – What is it?

Biogas is the captured gas that comes naturally from the anaerobic digestion of raw materials such as agricultural waste, manure, municipal waste, plant material, sewage, or food waste. An example would be the gas produced by your compost pile.

This biogas is a mixture of gases primarily consisting of methane and carbon dioxide, along with traces of other gases. On an industrial level specialized digesters are used to control and manage the process. The resulting biogas is classed as a renewable energy source.

However, biogas and Renewable Natural Gas are different. Renewable Natural Gas is actually a type of biogas. It is a very pure type of biogas (up to 99% methane) which makes it suitable for applications that have typically relied on traditional natural gas such as:

  1. Fueling vehicles – if biogas is cleaned and compressed in can be used as fuel
  2. A replacement for natural gas – if biogas is cleaned up and upgraded to natural gas standards, it can be injected into your local gas companies’ pipelines and used for commercial use, heating our homes, and even cooking.
  3. Electricity – a very clean biogas can be converted directly into electricity by using fuel cells.

The main contributors for biogas production are largely food and livestock waste, wastewater, and crops. The naturally occurring anaerobic digestion of waste product can be optimized, controlled, and contained using commercial anaerobic digesters. But not all waste materials break down at the same rate, so mixing multiple wastes in the same digester, referred to as co-digestion, can help increase biogas yields.

After biogas is captured, in needs to be cleaned and compressed to become a useful energy source. At this point, you may be wondering how biogas production translates to the air and gas industry. Without air compressors, blowers, chillers, etc. it would not be possible to produce biogas as the machines are used throughout the entire production process.

At the collect and clean stage there are multiple applications:

  • Blowers for capturing the methane produced by the decomposition in the landfill.
  • Oxygen generation for desulphurization.
  • Aeration blowers for wastewater treatment.
  • Air compressors for tooling, conveyancing, and general plant usage.
  • Industrial chillers for cooling.

When it comes to compressing the gas to a high-pressure that turns it into a useful energy form:

  • Belt and direct drive air compressors for compressing the gas up to 4,500 PSIG.
  • Compressors for grid injection.
  • Compressors for Tube Trailer injection up to 3,600 PSIG.
  • Pressure reducing systems to step the pressure down in stages.
  • Fueling stations and dispensers for NGV vehicles.

As we look to lower our impact on the environment, biogas will only continue to grow in importance. As the world population continues to grow and evolve, treating waste and needing fuel are two biproducts of this growth and biogas production offers one solution to this: taking waste and turning it into fuel.

If you are interested in learning more about biogas and RNG please contact the experts at Atlas Copco.