world’s first ever ethane carrier capable of using ethane liquid for propulsion -inspected by Capt. Delzin Irani
Marine inspection -Ethane Carrier inspection
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.