Malaysia’s Petroliam Nasional Bhd (Petronas) has placed a newbuild order recently for a pair of ABS-classed ‘Moss-type’ LNG carriers from Hyundai Heavy Industries.
According to ABS, these two ships will have 150,200 m3 capacity and be the largest Moss-type units ever built at HHI with spherical tanks 42-meters in diameter.
ABS notes, “because Moss-type tanks have no minimum filling limits, they are well suited to serve as shuttles to and from FLNG or other offshore facilities.”
Petronas’ first FLNG facility, currently under construction at DSME, is due to be installed offshore offshore Sarawak, Malaysia and is designed to produce 1.2 million tons per year of LNG. It is scheduled to be ready for start-up by end of 2015.
The Petronas ships will also feature ultra-steam turbine propulsion systems designed by engineers at Mitsubishi Heavy Industries. This system is expected to be about 15 percent more energy efficient than conventional steam turbines while offering an extremely long life time of up to 40 years, according to Mitsubishi.
The following is a diagram of an UST system, via Mitsubishi:
In the UST system, the reheater is the key differentiator which takes the high pressure steam and heats it from 2.2 MPa @ 365 deg C to 2.0 MPa @ 560 deg C before heading to the intermediate pressure turbine, resulting in improved thermodynamic efficiency according to engineers from Samsung Heavy Industries.
Feeding the high pressure turbine will be steam at 10 MPa, or 1450 psi.
ABS notes, the ships will feature full-length tank covers integrated into the main hulls which is expected to improve longitudinal strength and minimize structural discontinuity while at the same time allow for piping and passageways to be arranged on the tank-cover deck, improving safety and ease of maintenance.