LATTICE Technology has announced that the port cleaning ship with the first commercial lattice pressure vessel (LPV) has been successfully delivered to Ulsan Port Authority; this means that it is ready for service from this month.
Unlike cylindrical pressure vessels, LPVs have a box-like shape in which the geometry is fully flexible in terms of width, height and length. In addition to this, it is fully scalable in size. When the first LPV order was made a year ago, it was noted that in this case the LPV increased the storage capacity by 50% over a cylinder solution within the same tank installation space. Thus, with the same design pressure and the same vacuum insulation, the bunkering interval will be increased by 1.5 times.
LATTICE Technology CEO Keunoh Park said: “As this ship is the first LNG-fuelled vessel for public service in South Korea, the most stringent design rules for fabrication, inspections, and tests were applied and found to be in full compliance with the IGF Code; in fact, the LPV smoothly passed all of them without any problem.”
According to the statement, the LPV has been designed for a pressure of 9 barg and volume of 15 m3. The tank was manufactured and delivered to the supplier of the fuel gas system and thereafter tested under KR’s witness, and delivered as a combined package to Koryo Shipyard early this year. Over the last few months, the system has successfully gone through the cold test with liquid nitrogen and the gas trial test with LNG.
Director Jaeduck Kim of SNS Engineering, the supervisor of this project, said: “From the beginning I paid a special attention to this innovative tank technology. As the project proceeded, I was impressed by the beauty of this technology and became confident of technical capabilities of LATTICE Technology. Except for the shape giving increased capacity, everything was the same and as simple as for a cylindrical pressure vessel.”
Dr. Pål Bergan, CTO of the company, added: “Since it is a free-shape Type C tank technology, the LPV provides a wide range of benefits, especially the ability to fit any available space within a ship, and that this pressure vessel technology provides full scalability from a few cubic meters to tens of thousands of cubic meters. The ability to fit any space was well demonstrated by this project. When it comes to scalability, it is remarkable that the thickness of the structural component remains the same independent of size; clearly this is very different from cylindrical tanks for which the shell thickness increases proportionally with size. This feature enables us to design and fabricate very large size pressurised fuel and cargo tanks for liquefied gas.”
LATTICE Technology claims that it is now planning aggressively to offer applications of the LPV to other areas, including LNG fuel tanks for large ships, cargo tanks for small scale gas carriers and bunkering ships, fuel tanks for land vehicles, and fuel and storage tanks for liquid hydrogen. Recently, the company proposed a 50 000 m3 liquid hydrogen tanker with two 25 000 m3 cargo tanks with special vacuum insulation. Due to extremely low storage temperature and low density, liquid hydrogen transportation requires volume efficiency of cargo tanks, vacuum insulation, and pressure holding capability without BOG venting. These requirements exclude unpressurised Type B and membrane tanks as an option whereas the solution proposed by LATTICE Technology is believed to satisfy all formal requirements. Recently, a path towards commercialisation, a US$4 million research grant was provided in June 2019 to build three LPV tanks (0.6 m3, 35 m3 and 350 m3) for storing liquid hydrogen.