Bright Renewables - Biogas Upgrading - Membrane technology

Membrane biogas upgrading

Biogas purification with membrane technology - achieving the highest possible methane yield through membranes with high separation efficiency.
Bright Renewables - Biogas Upgrading - Membrane technology

Upgrading technology

At the core of our biogas upgrading system lies membrane technology. In addition to biogas upgrading, Bright can also provide technology for landfill gas upgrading. Biogas upgrading makes use of membrane technology whereas landfill gas upgrading makes use of membrane technology in combination with PSA technology. All upgrading systems benefit from the add-on of a CO2 liquefaction technology. This enhances CO2 recovery, further improving the Carbon intensity (CI) score.

Process steps

How does it work?

  1. Cooling. The biogas first enters the pre-treatment system where moisture (biogas cooling) and contaminations, such as H2S, are filtered out.
  2. Filtration. In the filtration step, the gas reaches filtering. This is done in the three filters filled with activated carbon. Two of these vessels contain active carbon for the removal of toxic hydrogen sulfide (H2S). The other vessel removes volatile organic compounds (VOCs).
  3. Compression. After that, the gas is compressed to reach the required pressure before entering the membrane system. The heat of the drying of the biogas, from the compressor, and from the cooling can be recovered.
  4. 3-stage membrane separation. The remaining gases after the pre-treatment include CH4 and CO2. The compressed gas mix flows through the 3-stage membrane system where the CO2 and CH4 are separated. The CO2 from this separation process can be recovered and liquefied.
  5. Post-treatment. In the after-treatment system, the produced biomethane is analyzed and checked if all specifications are fulfilled. Also, TetraHydroThiophen (THT) is added that gives the biomethane an odorant.
Bright Renewables Purepac Compact - Biogas Upgrading - Project SintOedenrode Netherlands

Biogas upgrading technology

After the gas treatment, clean biogas consists mainly of CH4 (methane) and CO2 (carbon dioxide). The gas flows through the 3-stage membrane technology where the CO2 is separated from the methane. The CO2-stream can be recovered and liquefied with our CO2 liquefaction technology. For the separation of carbon dioxide from biogas, Bright uses membranes with the highest selectivity available in the market – as they pass CO2 more efficiently and quickly than methane. Membranes with high separation efficiency, enable the maximization of renewable natural gas yield. Depending on the grid or user requirements, the gas can be purified to the preferred methane concentration.

Bright Renewables - Biogas Upgrading - Membrane technology

Membrane technology

The separation between the biogas and chemicals is facilitated through a three-stage membrane arrangement. In the first stages, the biggest separation between the CO2 and the raw biogas transpires. In the second membrane stage, the RNG reaches its desired purity. The third stage enables the achievement of maximum methane recovery. Through this patented design, the gas from the first and second stages is recirculated to obtain the highest efficiency and minimal methane loss (≤ 0.5%). This is a significantly lower methane slip value compared to other biogas purification technologies.

Biomethane / RNG (grid injection)
Bio-CO2 (CO2 liquefaction
Bio-CNG (virtual pipeline)
Capacity biogas flow
Methane slip
Methane slip with CO2 liquefaction
Electrical consumption
PurePac Compact
100-750 Nm3/hr (62 - 467 SCFM)
Membrane separation
≥ 99.5%
≤ 0.5%
≤ 0.1%
0.26 kWh/Nm3 of raw biogas
PurePac Medium
750-1,500 Nm3/hr (467 - 935 SCFM)
Membrane separation
≥ 99.5%
≤ 0.5%
≤ 0.1%
0.26 kWh/Nm3 of raw biogas
PurePac Grand
1,500-12,000 Nm3/hr (935 - 7477 SCFM)
Membrane separation
≥ 99.5%
≤ 0.5%
≤ 0.1%
0.26 kWh/Nm3 of raw biogas
Bright Renewables - Biogas Upgrading - Gas treatment skid

Upgrading landfill gas

In order to upgrade landfill gas, we use a combination of technologies. The Bright technology integrates a three-stage membrane upgrader system with a Vacuum Pressure Swing Adsorption (VPSA) process to efficiently separate methane from landfill gas. The VPSA technique enhances gas separation by adsorption, with desorption and rinsing occurring at low pressure for effective regeneration of the adsorption bed.

Bright Renewables - Carbon Capture Technology

PSA technology

This process is made continuous through multiple parallel vessels, allowing for high-purity gas output and minimal emissions. The nitrogen-rich purge gas is safely treated in a thermal impurity disposal system. This combination ensures a highly efficient and environmentally friendly solution for biomethane production.

Biogas upgrading: how does it work?

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