Processing biogas into biomethane

Biogas generated by BTS biogas power plants can be used not only to produce electricity, heat, cold and fertilizer but also biomethane. Through biogas upgrading (biogas processing), methane is separated from all other gases, chiefly CO2. This upgraded gas discloses two new possible applications, on the one hand the typical supply into the existing methane network, on the other the use of biomethane as fuel for vehicles. Moreover 100% pure CO2 (bioMETANm) can be produced,  a gas which can be used especially in the food industry.

Biogas can be upgraded either with bioMETANw, a process involving pressure water washing, or with bioMETANm, i.e by means of membranes.

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bioMETANm - Process employing membranes

Biomethane Process employing membranes
bioMETANm - Process employing membranes

In this process the biogas is first purified from hydrogen sulfide and then brought to higher pressure with a compressor. The methane is then separated from CO2 by means of membranes. A clever sequence of separation stages combined with CO2 recovery allows to separate 100% of the methane.

The recovery of CO2 facilitates the 100% methane separation from biogas and subsequently provides food-safe CO2.
To achieve these goals, after going through the membrane separation the part containing CO2 is further compressed.  The CO2 is subsequently liquified, while non-condensable gases are separated within a downstream separator and conveyed again to the membrane unit. This process guarantees 100% pure CO2 for use in the food industry.


  • Low maintenance
  • Production of 100% methane from raw biogas
  • Methane slip < 0,1 %
  • Food grade carbon dioxide (CO2) as a further source of income




bioMETANw - Pressure water washing process

This process consists in dissolving CO2 and hydrogen sulfide in water and separating them from the biogas.

The biogas is brought to higher pressure and cleansed with counterflow water in a packed column. At this stage the water absorbs the "unwanted" gases, whereas the purified gas from the column is drained, dried and made available for further use, i.e. pumped into the gas network or directly employed.

The water containing unwanted gases is then led into a flash-column where it undergoes a tension reduction.  In the following step, CO2 is extracted in  another column by means of air, and the purified water returns to the washing column.

Thanks to this simple process, it is possible to avoid using chemicals and achieve an effective biogas purity.
Thermal energy can be derived at different points in the system and used to heat the tanks of the biogas plant.


  • maximum heat recovery
  • low maintenance
  • very high gas purification grade 
  • low energy consumption
  • low methane loss
  • low water consumption



  • bioMETANm
    Operating pressure: 10 – 17 bar
    Methane slip: < 0,1 %
    Internal power
    ca. 0,20 kWh/Nm3 raw gas
    Installation: Container

  • bioMETANw
    Operating pressure: 5,5 – 6,5 bar (overpressure)
    Methane slip: ca. 1 %
    Own electricity consumption: ca. 0,23 kWh/Nm3 raw gas
    Installation: Technical equipment in the container, columns in the open

Pressure water washing proves profitable to large size plants (>2MW), whereas membrane processing is rather used in small and medium plants.



New American Sharholders in BTS Biogas

US Investor Group Acquires Large Minority Stake

  • GTS Syngas
  • TS energyGROUP