Gas Upgrading Unit
Upgrading Unit ‒ Biogas Refined to Biomethane
Biogas upgrading unit refines raw biogas to high-quality biomethane for gas grid injection or utilization as transport fuel. With the PSA and membrane upgrading technologies do not require any additional chemicals or water. Methane content of the purified gas is high.
PSA Technology for Biogas Upgrading
Widespread PSA gas upgrading technology is based on Pressure Swing Adsorption, where a carbon dioxide selective molecular sieve captures the raw gas CO2 in certain pressures and releases it in another. Moisture and impurities of the raw gas (such as hydrogen sulfides or siloxanes) are removed in the pre-treatment phase before the upgrading process.
PSA units are also suitable for refining biogas, landfill gas or pyrolysis gas. Feasible PSA upgrading technology sizes start from 350 Nm3/h capacities and the units can be scaled up.
Advantages of PSA technology offered:
- Low energy consumption 0.16-0.24 kWh/Nm3
- Small (less than 1%) methane slip
- High-quality biomethane as an end-product
- No need for water or chemical utilization
- Compact plant size; modular, containerized solution
- Automated and remotely controlled process.
Membrane Technology ‒ Flexible Operating Capacities
In membrane biogas upgrading technology, gas flows through many thin fiber tubes with selective wall material. The separation of carbon dioxide from methane occurs because of its diffusivity through the fiber wall material. As carbon dioxide slips through the walls, methane travels to the other end of the tubes and is collected without CO2. The cycle is repeated in two or three process steps to gain high enough methane content.
Membrane technology advantages:
- Membrane technology unit sizes starting from 50 Nm3/h of input biogas
- Low investment costs
- Easy, automated and remotely controlled process
- High-quality biomethane as an end-product
- Low methane slip
- No need for chemicals or water.