40
LNG
INDUSTRY
SEPTEMBER
2014
LNG promises an excellent environmental performance
compared to conventional ship fuels. Its emissions are as
follows:
Sulfur oxide (SO
x
): 0
Particle matter (PM): 0
Nitrogen oxide (NO
x
): -90%
Carbon dioxide (CO
2
): -20/-25%
The LNG industry has an excellent safety record and
industry users want to ensure that best practice when
fuelling vessels is maintained, as opposed to current bunker
oil fuelling where spills are a well-known fact of life. With a
liquid to gas ratio of 1:600 for LNG, it is understandable that
the industry can not afford to have product spills or releases
to atmosphere.
Therefore, the industry has looked for solutions that
meet the stringent safety and environmental standards
while having minimal impact on productivity. Alpha Process
Controls (APC) has designed and manufactured the LNG
marine Emergency Release Coupling (ERC) as one solution.
The industry requirements included a simply-designed
ERC system that did not require costly Hydraulic Power
Units (HPUs), but did include a two stage operation that
enabled the controlled shutdown of internal valves (ESD1)
and then coupling separation (ESD2). The controlled
shutdown would allow high flow rates through the coupling
and would not compromise the vessel’s pipework or pumps
in the event of a drift-away.
An additional requirement was a minimum inventory of
product between the internal valves when shut down prior
to separation.
To provide an alternative to existing systems, APC has
developed a family of couplings, which effectively support
the safe transfer of cargoes including LNG, LPG, vinyl
chloride monomer, liquid oxygen, nitrogen, and many other
hazardous liquids and gases.
Meeting market requirements
The couplings comprise the following models, which meet
multiple industry requirements, not only in the offshore
LNG market, but also other offshore and onshore sectors:
Safety breakaway couplings – these are located
between terminal pipework and flexible loading hoses.
This system is used to safely transfer bulk hazardous
liquids and gases, including cryogenics. The couplings
are typically used in the liquid transfer between
terminals and road tankers, rail tankers and ships.
Breakaway couplings are also used in ship-to-ship
transfer, as well as supply vessel to drilling platform/oil
drilling rigs and offshore applications.
Marine breakaway couplings – these stainless steel
couplings come in sizes from 4 to 10 in. and offer a wide
range of seal trims available to suit specific applications.
They also include an innovative inbuilt damping system
to reduce the effects of pressure spikes should the
coupling be called upon to separate during full flow
transfer. The couplings can also be easily recovered and
reassembled after a drift-away incident.
Cryogenic breakaway couplings – these incorporate
unique sealing technology and are able to operate at
extreme temperatures.
Fluiseal quick connect drybreak coupling – this is a
high quality, reliable valve coupling that is used in the
loading of flammable, toxic, and corrosive products into
tanker vehicles on road, rail, barge or supply vessel to
oil rigs.
Research and development
To enable APC to develop an alternative marine breakaway
ERC up to 10 in. bore with a minimum flow restriction and
incorporate internal damping using cryogenic liquid, the
company initiated a five-year R&D programme.
The coupling’s internal damping system was a key
breakthrough, which meets the requirement of reducing the
effects of pressure spikes should the coupling be called
upon to separate during full flow transfer.
The actuation of the coupling needed to be as simple as
possible, avoiding costly hydraulic systems that are
currently on the market. APC utilised its experience in
smaller ERCs used on loading arms that are activated by a
simple pull cable.
At this time in the development the company
approached industry experts and end users for their
Figure 1.
ERC cryogenic testing.
Figure 2.
Testing facility.
