Marine inspection - Ethane Carrier inspection
World’s first ever ethane carrier capable of using ethane liquid for propulsion - inspected by Capt. Delzin Irani
Marine inspection: Having sailed on gas carriers for majority of his sea going carrier, our gas carrier expert Capt. Delzin Irani of Constellation Marine Services had never come across any dedicated ethane carrier capable of carrying pure Ethane cargo at -104 deg C and using the same liquid ethane as fuel (liquid injection) for the main engines. She is the prototype ethane carrier built in the fourth quarter of 2016 from Dayang Shipbuilding Co., LTD, China. She is Liberian flagged and Monrovian registered vessel, who is classed by DNV-GL and owned by EcoStar36 Chartering 2 GmbH & Co. KG, Germany. Another aspect by which the inspected vessel is unique than all other gas tankers in the world, is that she has the accommodation forward which has never been seen or heard of in the gas tanker industry.
Marine inspection - Cargo Suitability
inspection
Constellation Marine Services were approached
by the leading marine risks underwriters for
the charterers, headquartered in London, United
Kingdom, to carry out the cargo suitability
inspection of the Ethane Carrier during her
second ever voyage from Houston, USA to Europe.
We attended onboard the vessel LPG/c “Ethane
Carrier”, whilst she lay safely afloat made
fast starboard side along to Dock No 7, Enterprise
terminal, Morgan’s point, La porte, Texas, USA
on 01st Feb 2017 to carry out assessment of
the cargo worthiness and to determine if the
risk involved in cargo operations are mitigated.
After boarding the first of its kind and highly
unique LPG carrier we noticed that she was capable
of carrying out her entire loading in 24 hours
and maintaining Liquid Ethane at its boiling
point of -104 Deg C with the aid of 3 highly
sophisticated cargo compressors, each of which
has 2 condensing units (i.e Traditional sea
water cooled condenser and Mycom condenser using
Propylene as coolant) for condensing the compressed
Ethane gas into liquid prior sending it back
to the cargo tanks in liquid form. The cargo
containment system is similar in functionality
to the standard LPG semi pressurized ship, however
is of a different shape such as tri lobe independent
Type C tanks which is exclusive compared to
the bi lobe independent Type C tanks of standard
LPG vessel
She is a prototype to the LPG industry with
a maximum ethane cargo carrying capacity of
approx. 36000 cbm which has the capability to
use liquid ethane as fuel in the main engine
apart from the conventional LNG carriers which
use Methane vapors, and not liquid, as fuel
for the main engine. The liquid Ethane is stowed
in two Independent Fuel Gas Tanks, aft of No
3 Cargo tank which has its 2 independent deep
well pumps capable of transferring liquid directly
to the engine room fuel supply line to the Main
engine. Double wall segregation is available
in the fuel supply line and dry air is continuously
being circulated in the surrounding space of
the pipeline. There is also a fixed gas detector
fitted between the two layers of the double
walled pipeline. The gas detector continuously
monitors the atmosphere in the double wall segregation
for any presence of HC content greater than
1% LEL and if it does, the automatic switches
will
Cut the supply of ethane cargo and change over
the mode of fuel supply of the Main engine to
Heavy fuel oil or Marine Gas oil depending upon
the SECA area which the vessel is trading in.
This new arrangement is fitted just forward
of the cargo control room (CCR) on the main
deck and can be witnessed from the CCR.
Marine inspection - Procedures and
requirements for Safe Cargo Operations.
The vessel’s SMS had covered all the procedures
and requirements for safe cargo operations onboard
the vessel and safe care of cargo during transit.
All the possible risks were identified in the
risk assessment sheets which were incorporated
in the Lloyds register mariner software. We
identified 14 risks onboard during the loading
operations, all of which had mitigation measures
in place. The ship officers were highly experienced
in the LPG trade sailing mostly on Ethylene
carriers which are similar to this vessel. Loading
operations were going on smoothly with the cargo
pumps regularly, every 30 mins, being turned
by hand and kick started with the electrical
motor to ensure smooth functionality. Another
unique feature on the inspected Ethane Carrier
was that the High High level alarm was set at
98% which when activated would not allow further
loading of cargo in the tanks. This is an inbuilt
safety feature preventing the cargo tanks from
the overfilling hazard associated with cargo
operations.
To summarize, Our Capt. Delzin endeavor was
to see the vessel’s cargo worthiness and mitigation
of risks involved with cargo operations were
being complied with as per international standards
of SIGTTO (Standard institute of gas tankers
and terminal operators) and IGC (International
Gas carrier) code.