Looming large on your right after driving south from downtown Osaka on the bayshore Route 4 of the Hanshin Expressway is a huge cylindrical structure. This is the No. 5 liquefied natural gas (LNG) tank set up at the Osaka Gas Senboku Terminal Ⅰ. The tank, with an outer diameter of about 91 meters and height of about 60 meters, is so large in area that it could house a facility equal to two castle towers of Osaka Castle.
An LNG strage tank is a huge container whose purpose is to store LNG, kept in its liquid state at the very low temperature of minus 160 degrees Celsius. The No. 5 LNG tank is capable of storing 230,000 cubic meters of LNG, and was the world’s largest aboveground LNG tank when it was constructed. The project to construct the No. 5 tank at Senboku Terminal was launched in 2011. It marked another challenging project for Osaka Gas, which constructed an LNG strage tank with a storage capacity of 180,000 cubic meters in 2000, the world’s largest when it was built.
Osaka Gas has tried to build a larger-capacity LNG tank as part of its efforts to reduce construction costs. Building one 230,000-cubic-meter tank would cost less than building two 115,000-cubic-meter tanks, for example. In addition ,if construction time can be shortened, construction costs would be cut further.
Constructing an LNG strage tank as large as the No. 5 tank was an unprecedented challenge for engineers involved in the project. It required the achievement of aspects usually considered incompatible—enlarging a tank while shortening construction time. Given that nobody in the world had constructed such a huge structure for LNG storage, the project members, as engineers, could not conceal their excitement when assigned to the project.