We have built many LBG refueling stations from the ground up, often in partnership with Chart Industries, Inc. such as the recently commissioned Gasum LCBG (liquid biogas and compressed biogas) stations in Ålesund and Luleå.
However, we have also developed our own decoking compressor solution to reduce the LIN costs of cooling the LBG tanks. Although the cryogenic vacuum tanks are incredibly well-built thermoses, there will always be some liquid biomethane that heats up above the boiling point of -160 degrees Celsius and turns into gaseous form, the so-called decoction.
If the decoction is allowed to remain unhandled, sooner or later the pressure inside the cryogenic tank would increase and cause the safety valves to release pressure. Although the safety valves are designed to do exactly that and thus guarantee a safe handling, we want to avoid any methane release into the atmosphere. Our customers normally choose to use LIN (liquid nitrogen) at -196 degrees to cool the biomethane and thus avoid decoking.
LIN cooling is costly and therefore we prefer to utilize the decoction instead by compressing the gaseous biomethane and sending it to the internal CBG storage, from which the biomethane can be used to refuel vehicles with compressed vehicle gas also called CBG or RNG (Compressed BioGas or Renewable CNG). This solution can be retrofitted to almost any LBG refueling station and makes the most sense when the station already has a CBG refueling system. This was the case at the new Air Liquide Skagerak LCBG station in Gardermoen, Norway, where we delivered the Boil-off compressor system and CBG storage as an add-on module to the filling station last fall.
In our Boil-off solution, we can choose the right compressor type and size based on estimated demand, and in the Gardermoen case, we chose to build it with a smaller compressor block from BAUER. The real magic, however, lies in the automation intelligence that our automation team provides.
"If the LBG filling station does not already have a CBG dispensing solution in place, the decision to upgrade with our decoking solution may not be as obvious", says Johan Wideman, CEO of Processkontroll Green Technology . "In that case, we are happy to help you calculate the benefits of installing a complete decoking solution and what CBG dispensing package is needed.