Gas Upgrading

Upgrading Biogas to Fuel Quality – Biomethane

With the increase in fossil fuel demand and prices, electricity costs to the consumer will continue to increase.

The upgrading of biogas to biomethane (bio natural gas) holds great potential with many applications in South Africa:

  • Use as a vehicle fuel
  • Injection into the natural gas grid
  • Production of heat and steam
  • Production of chemicals

Biomethane is produced by removing moisture from the gas, desulphurising and finally refining to natural gas quality through the separation of carbon dioxide by the employment of two main technologies:

MEMBRANE SEPARATION TECHNOLOGY

Biogas upgrading via membrane separation is fast becoming the popular choice. The membrane consists of a cylinder packed with hollow porous fibres where methane and carbon dioxide is separated into two different streams.

WATER ABSORPTION TECHNOLOGY

This process upgrades biogas by scrubbing H2S and CO2 through a circulating water system. Both hydrogen sulphide and carbon dioxide are water soluble components, while the less soluble methane molicules pass through.

 A Clean Fuel

Upgraded biogas is cleaned to a level of about 97% Methane (CH4) . Biomethane can then be compressed further for compact storage and to be used as a vehicle fuel. One cubic meter of upgraded biogas is approximately the same as one litre of diesel, and due to it’s purity, biomethane is one of the cleanest fuels in existence.