Reliquefaction plant

A reliquefaction plant is the gas-handling system on an LNG or LPG carrier that condenses cargo boil-off gas back to liquid and returns it to the cargo tanks instead of venting or burning it. On an LNG carrier it draws boil-off with a centrifugal compressor and condenses it in a cryogenic cold box cooled by a closed nitrogen Brayton cycle; on an LPG carrier a direct or indirect refrigeration cycle recondenses the warmer cargo vapor. Reliquefaction lets a slow-speed diesel ship carry its cargo intact, recovering the boil-off that a steam or dual-fuel ship would otherwise burn.