session viii_ capt sanjay gupta
DESCRIPTION
LNGTRANSCRIPT
FSRU Business Case
Case for floating storage and regasification centers on
three issues:
• Its economic attractiveness
• Its technical acceptability and
• Its flexibility as FSRU’s can be moved from one
demand centre to another. Fluctuations due to
seasonal demands can be mitigated.
Moss type LNG Tanker
• FSRU’s ability to move from one demand centre to another
and retaining ability to trade as LNG carrier makes them an
interesting option.
• Part of the attraction for FSRU’s also lies in the fact that
residents tend to favor energy supply solutions that are
situated far away from where they live…NIMBY syndrome.
• Attraction is also obvious in areas where economic growth
is uncertain or where there is an element of political or
economic instability.
• FSRU’s provide a faster return on capital.
Onshore terminal development requires extensive
planning. It takes more construction time as compared
to the FSRU’s which are mainly converted from an
existing LNG carrier.
In LNG carriers, much of the required equipments are
already available. Broadly time required is 18 months
for engineering and 6 months for the shipyard work.
No generic solution to industry off shore’s regasification
needs. Each FSRU has to be designed to meet the
specific requirements of the charterer for particular
project.
Design of FSRU
Typical details of a FSRU converted from a LNG carrier
• Length-289m, Breadth-44.6m, Draft-11.4m
• Performance
Time for berthing loading and unberthing-24hrs
Cargo tanks capacity-129,000cbm
No of tanks 5, Moss type
Gas send out
Tons/ hr-231
MMTPA-2.02 MMTPA
There is no single factor that dictates which kind of LNG
carrier makes the best FSRU.
Indeed availability and cost are prime considerations.
Technical community tends to favor old vessels with Moss
(spherical) type cargo containment systems, especially if
the intention is to moor the FSRU in an offshore location.
The self supporting Moss type tanks have strong structural
integrity and do not have operational cargo filling
restrictions.
A more modern membrane tank vessel has a more efficient
propulsion system and may be more attractive if the
intention is to continue using the vessel to trade LNG.
FSRU Storage capacity is dictated by the port and supply
logistics.
Gas send capacities, temperatures and pressures will be
influenced by maximum and minimum rate demands.
Mooring system design will depend on the local weather
conditions and the jetty configuration.
FSRU’s communication links and ESD systems are
integrated with the onsite LNG and natural gas handling
systems.
FSRU Terminal allows safe berthing of standard LNG
carrier without any need of modification.
FSRU Terminal can be moored to seabed with a turret
mooring arrangement.
Turret is equipped with a turntable which allows 360 deg
continuous rotation of the FSRU.
The LNG tankers off loading to the FSRU may be moored
in a side by side configuration. The other loading tanker
may also be moored across the pier.
Mooring
FSRU Golar Freeze designed for
side by side mooring
FSRU Golar Spirit receiving cargo
across the pier for storage and
regasification
Side by side mooring system consists of:
• Primary and secondary fenders
• Nylon Mooring lines. The lines shall be connected to the
wire part of the LNG carrier by special mooring shackles
• Roller fairleads for guiding the nylon lines as required.
• Hydraulic quick release hooks with integrated capstan
and adjustable release load.
• The Terminal will be fitted with an azimuth thruster for
control of the terminal during LNG carrier berthing / un-
berthing.
• FSRU’s provided with standard loading arms to allow
side by side transfer of LNG and vapor return.
• Loading arms similar to the type of that is used on
onshore terminals however modified to account for
relative motions between carrier and FSRU.
• Fitted with equipment for guiding the arms onto the
carrier’s connection flanges.
• Wide capacities FSRU’s ranging from 1,25,000 cbm to
1,50,000 cbm are in operation.
Loading Arms
• LNG is sent from the tanks to the regasification skid.
Which generally comprises of booster pumps and steam
heated vaporizers.
• The booster pumps will increase the pressure to about
85 to 90 bars.
• High pressure LNG is vaporized.
• Regasification can be both in open or closed loop mode.
LNG regasification system
Skid Mounted Regasification unit
•In the closed loop operation the sea water cooled in the
vaporization process is reheated using steam rather
than being discharged into the sea.
•Few designs use combination of propane and then sea
water to heat the gas to around 15 deg C.
•Gas is passed through a metering unit and is sent to
the subsea cable via the gas swivel and flexible risers
or into the shore arms. Gas send out pressure is around
85 bar.
•FSRU designs also allow gas transfer to shore through
high pressure loading arms fixed to the jetty
Issues • Technical specification must be robust. Time spent with
the end user to make specifications of the FSRU should
be as close as possible to the operational requirements
is important.
• Converting existing LNG carrier into FSRU: Integration
requires extreme efforts.
• High pressure associated with FSRU operations
introduce a new set of risks not present on conventional
LNG carriers.
• Operation and maintenance of the vessel
• FSRU have upgraded fire and gas detection systems
and fire fighting systems
• In addition a more sophisticated emergency shut down
system based on the rules for offshore oil and gas
operations is provided.
• As an FSRU forms part of the shore infrastructure, EIA
and assurance of vessels compliance with the local as
well as international marine requirements are also
central issues.
Maximum boil off from the storage tanks is as per design
requirements of the LNG carrier. Boil off is collected and
used as fuel for steam generation in the FSRU boilers
BOG Handling
Power Generation on board is similar as in any of the
conventional or new generation LNG Carriers.
Metering station is provided
Cost, speed of delivery and flexibility are the main
advantages of FSRU’s.
Concept of FSRU’s may provide in general a rapid and
competitively priced turnkey alternative to a shore based
gas terminal.
FSRU business is challenging.
It involves sound aggregation of shipping and energy
technology, LNG market awareness, commercial skills and
marine operating experience.
Conclusion
Thanks