Alfa Laval heat exchanger for cargo reliquefaction
DuroShell is said to dramatically increases resistance to thermal and pressure fatigue compared to other welded solutions due to a patented roller coaster plate pattern, allowing it to condense cargo with a higher ethane content.
Similar to AlfaRex – Alfa Laval’s existing plate heat exchanger for LPG/E cargo condensation – DuroShell is a laser-welded solution combining high thermal efficiency with a very small footprint. But DuroShell withstands pressures of up to 35 bar (when titanium plates are used) and temperatures as low as 198°C, compared to the 30 bar and -50°C limits for AlfaRex.
Matilda Mellby, application manager, gas components at Alfa Laval said: “An extended pressure range is important as the ethane level in LPG/E increases. DuroShell is more than robust enough to handle ethane condensation, which demands pressures in excess of 30 bar.”
The roller coaster pattern ensures even expansion around the plate circumference, which eliminates potential weak spots and increases the heat exchanger lifetime. The entire plate pack is pre-compressed to minimise the effect of large differences and variations in temperature.
Further strength is added by the distribution tubes that extend through the laser-welded plate pack, relieving stress on the plate pack and ensuring the best distribution of media. Together with the roller coaster pattern, which creates high turbulence even at low velocities, the distribution tubes ensure thermal performance.
