High-pressure ball valve for supercritical CO2 (sCO2)

The characteristics of carbon dioxide in the supercritical aggregate conditions lie between those of gas and liquids. They thus differ significantly from the characteristics under standard conditions. Supercritical CO₂ (sCO₂) is the condition in which carbon dioxide is neither a liquid nor a gas. The substance reaches this at around 31°C and 74 bar. Here, sCO₂ combines the advantages of low viscosity with high density, allowing compact components as well as low power plant footprints. In addition, numerous studies have shown that sCO₂ cycles have the potential to achieve higher efficiencies than conventional energy conversion plants.

The investigation of the flow behavior and heat transport of supercritical CO₂ at 300°C and ∆p up to 315 bar is performed in a pilot plant. This demanding process requires particularly reliable high-pressure ball valves. For this purpose, the 3-part ball valves of the INTEC system technology type INTEC K811-S-HT DN25 PN400 with stem extension INTEC 11 and manual gearbox are used. These are trunnion-mounted ball valves with metal-seated and both side spring loaded seat rings. The ball is made of Superduplex material (1.4980) and coated with a nickel-based hard alloy (SC4) by thermal spraying with subsequent melting to produce a non-porous hard material, as are the ball seats.

sCO₂ attacks the sealing materials PTFE as well as graphite. Therefore, none of these sealing materials may be used in places with direct contact to the flowing medium. The purely metallic and gas-sealing ball valves from KLINGER Schöneberg are designed for these extreme conditions and meet the high process requirements.

INTEC K811-S-HT DN25 PN400
with stem extension INTEC 11 and manual gearbox.