Thermax Inc. has announced that it has recently supplied Keppel Shipyard Limited with LNG Direct steam vapourizers to be used in the first ever conversion of a Moss type LNG carrier, Golar Spirit, into a floating storage and re-gasification unit (FSRU).

Moss Maritime of Norway provided engineering work for the complete system, with Thermax Inc. providing the thermal design for the cryogenic vapourizers and downstream gas temperature control - using LNG injection. The vapourizers use steam generated onboard by existing steam boilers as a heat source to vapourize over 240 tonnes per hour of LNG.

The design pressure of the vapourizers exceeds 85 barg requiring a wall thickness over 55mm as well as 1500 lb rated flanges, with each unit over 8m long and weighing in excess of 5500kg. The vapourizers are part of an LNG re-gasification skid that will be situated between the existing storage tanks.

Designed and built in accordance with DNV class rules and ASME pressure vessel codes, the units were required to be pressure tested and cold tested prior to shipment. Cold testing required passing liquid nitrogen through the units to ensure the suitability of the materials and design for cryogenic temperatures.

As an FSRU Golar Spirit will be able to process up to 2 million tonnes of LNG per annum and dispatch gas at variable gas send-out pressures up to 90 bar.

Thermax Inc. has been designing and manufacturing vapourizers for LNG and other cryogenic fluids for over 35 years, using heat sources such as ambient air, steam, water, electricity, and many other combustion gases that can be found throughout the world.