Everllence will supply the core compressor and expander technology for Stockholm Exergi’s bioenergy with carbon capture and storage (BECCS) project. BECCS is a technique for permanently removing biogenic CO2 from the atmosphere. Combining CO2 capture with heat recovery in Europe’s largest biomass-based combined heat and power plant in Stockholm, the company will capture and permanently store large quantities of biogenic CO2, resulting in carbon removal from the atmosphere and creation of so-called negative emissions.
The facility, located at the Värtaverket biomass power plant, is designed to capture and permanently store biogenic CO₂ released during the combustion of forest-based biomass. The carbon capture plant will be equipped with Everllence’s electrically-driven MAX1 compressor train for handling the flue-gas, comprising the AG110 axial compressor and the EN080 axial expander.
The flue gas with the CO2 meets a solvent liquid, which mostly consists of water and potassium carbonate. Pressurized potassium carbonate reacts with CO2 and H2O, which forms potassium bicarbonate. When the potassium bicarbonate pressure is lowered, the reaction goes in the opposite direction, releasing CO2 and H2O. In this way, the process works continuously and the CO2 can be separated and captured.
After the capture process, the biogenic CO2 will be purified and then liquefied. The purpose of the liquefaction is to make transportation more efficient, since liquified CO2 requires much less volume than CO2 in gas form. The pressure can, typically, be 101 psi (7 bar), with the temperature -58˚F (-50˚C). After liquefaction the carbon dioxide is stored in buffer-tanks, before being shipped to the final storage site.
The carbon dioxide will be stored in sub-water sedimentary bedrock at depths greater than 2624 ft. (800 meters), which is the requirement to ensure that the carbon dioxide is liquid or in a so-called super critical phase.
