Biomethane polishing cleans upgraded biogas or natural gas to reach lower concentrations of CO₂, which makes it possible to liquify the methane gas. Without CO₂ polishing, the CO₂ in the gas would freeze and crystallise, which causes problems for the liquefaction process.
To overcome these problems, Ammongas’ polishing process, which resembles a biogas upgrading plant, removes down to <50 ppm of CO₂ from the methane gas. At this CO2 level, the gas can be liquefied without complication and is ready to be used as a fuel source or for transport.