CLEANPORT is a project aiming at optimising and identifying new standards and regulations for the use of LNG (liquefied natural gas) and NG (natural gas) in passenger and vehicle ferry vessels. In order to carry out the project, a Pilot was installed and tested, which helped to assess current real state of regulations, identify their gaps and detect regulatory aspects requiring modifications.
Furthermore, it served to test the feasibility of the project and its usefulness for future wide scale implementation. Pilot installation was composed of the following three main elements:
Abel Matutes is a 190-metre-long ferry with a capacity of 900 passengers and has 2235 lineal metres for rolling vehicles. It operates the line between Barcelona and Palma de Mallorca in the Balearic Islands (approx. 300 km). Average speed is 21 knots.
A gas fuelled engine and a 30 m3 LNG storage system (one week autonomy) has been installed on ferry’s deck number 8. This includes a gas treatment plant that is also located on the same deck next to the storage tank. The new engine is fully integrated within the ship’s electrical and control systems. The engine is able to run with LNG coming from the ship’s tank, or with NG that could be supplied directly from the dock. The ship required the following principal activities:
a) An additional natural gas engine (Rolls-Royce Bergen C26:33), used during ship port arrival and departure, and while ship is berthed.
b) A LNG cryogenic tank, and a gas treatment plant, in addition to the necessary pipework for LNG tank recharging, connection of the tank to the inlet at the hull, and for the pipelines connecting from the LNG tank to the engine, with all the necessary pumping, control and safety systems.
c) A natural gas (NG) connection piping that connects at the inlet point located on the hull, to the gas engine deck number 8, together with the appropriate control and safety systems. The ship does not include a NG tank, as the intention was to supply NG directly from a gas pipeline in the port.
Set of figures on LNG retrofitting on the Abel Matutes ship
Ship bunkering system has been defined as a TTS (Truck To Ship) system, as the LNG volume needed each week is just below 20 m3, and the ship storage capacity is 30 m3. The bunkering system is based on an LNG trailer supply (see picture). The trailer is loaded at the existing LNG terminal at Port of Barcelona using the existing LNG truck loading infrastructure.
The Truck To Ship system required CLEANPORT project to develop a small LNG mobile skid for the LNG transfer, inertisation of the pipelines and to store the LNG transfer hoses. The skid includes LNG pipe with valves and instrumentation to connect the two hoses to the truck and to the ship, a nitrogen inertisation system, including nitrogen storage bottles, valves, instrumentation, an ESD (Emergency Shut Down) Panel and fire extinguishers (see picture). Refuelling procedure involves the transfer of approximately 26 m3 of LNG in a 1 hour period. Minimum pumping pressure is 15 bar.
From an operational perspective, the LNG transfer hose is connected to the bunkering station skid located onboard the ship and this connection is equipped with a break-away type connection system, as well as a set of tightness-proof automatic valves. In the unlikely case that an excess of tension makes the transfer hose break or fall down, the break-away system is activated, disconnecting the transfer hose and sealing the pipe on board to avoid any LNG leak.
In order to control every stage of the operation, both from port side and from aboard the ship, the LNG transfer skid is equipped with a “ship to shore” communication system, able to launch the ESD (emergency shutdown) procedure in case of emergency from both sides. ESD can be launched manually from shore and automatic from the ship.
• Shut down of LNG pumping
• Automatic closure of the cut-off valves installed inside the pipeline
• If possible, hose disconnection from the bunker station
Elements of the bunkering system that are stored at the Port include: the hoses; the skid for LNG transfer equipped with the nitrogen rack for inertisation and the ESD panel; and the fire extinguishers, all of which are stored in an enclosure area.
LNG TTS Bunkering system
Skid for LNG transfer and pipelines and hose inertisation
The NG network extension which would allow for an alternative natural gas supply while ship is berthed, is a possible alternative to the LNG system. That is, the ship’s natural gas engine will be able to be fuelled either from the NG connection to port, or from the on-board LNG storage system.
NG could also be provided from shore with a mobile CNG rack connected to the LNG skid and to the ship through the transfer hoses. This second NG mobile supply solution will provide a versatile solution when the berthing position of the vessel is not fixed at the port as the berthing concessions are always temporary.
Natural Gas bunkering fixed system would require the following specifications for the current berthing position of the vessel:
• Extension of the underground NG network existing at the Port of Barcelona, consisting of a new 780 m-long high-pressure (12 bar) NG line extension, that will be built in steel with diameters between 6 and 8 inches and 3.6 mm thickness, according to standard UNE-EN-10208-2-Gr L245. The system will require a gas regulation and measurement station, to be located about 20-30 metres away from the berth, that will reduce pressure to 8 bar (which is the designated operating pressure of the ship’s gas engine)
• The system will also need a flexible connection pipeline from the station to the ship, purging and inertising systems, and safety and fire systems. It will have to have the following functionalities:
- “Fast plug” for quick connection and disconnection.
- Operating pressure of up to 12 bar.
- Flexible hosing to support the ship oscillating movement. Diameter: between 2 and 4 inches. Length: 40 metres. Flow rate: 500 m3/h.
- Maximum safety
- Minimum purge needs while disconnection process.
As the bunkering berth of the Abel Matutes ferry could not be changed as was envisaged at the beginning of the project, the work to install the natural gas pipeline to the actual berthing position of the vessel was very complex and such an installation was predicted to have an exorbitant cost, so that construction of this infrastructure could not be justified during the duration of the project.
NG bunkering system diagram