DESIGN AND CONSTRUCTION OF GRAVITY BASED STRUCTURE AND MODULARIZED LNG TANKS FOR THE ADRIATIC LNG TERMINAL

摘要

Construction is under way on the world's first offshore LNG storage and re-gasification terminal, to be installed and operated in the Northern Adriatic Sea, about 17 kilometers east of Porto Levante, Italy. The Adriatic LNG (ALNG) Terminal is designed to deliver 8 billion standard cubic meters of gas into the Italian gas grid via a 30" pipeline to shore. Start-up of the terminal is targeted for 2008.rnThe terminal is a large gravity based structure (GBS), housing two steel LNG storage tanks and a topsides re-gasification facility. The overall dimensions of the GBS are 180m long, 88m wide, and 47m high, resting on the seabed at 29m mean sea level. The two 9% Nickel (9%Ni) steel LNG storage tanks each measure 155m long, 33m wide, and 28m high. Each tank weighs approximately 4500mt; the constructed weight of the terminal will be approximately 290,000mt.rnThis paper summarizes key aspects of the design and construction of the concrete GBS and modularized LNG storage tanks, whose construction were both initiated in early 2005. It will discuss some of the unique engineering aspects associated with the facility's global design, including:rn1. The seismic and metocean considerations that govern the terminal design.rn2. The design of the first-of-a-kind 125,000 cubic meter modularized storage tanks, and the engineering challenges associated with their installation and operation inside a confined GBS structure.rn3. The construction of the concrete GBS in Algeciras, Spain, and how this relatively undeveloped site was converted to support the construction of a 250,000mt concrete structure, the integration of two 10,000mt LNG tanks and 20,000mt topsides facilities, and marine operations required to initiate transportation of the completed facility to the Adriatic.rn4. The unique challenges of the fabrication of the 9%Ni LNG tanks in Ulsan, Korea, and their transportation to the Algeciras site.