Experience of Operating an Underground LNG Storage Pilot Cavern
摘要
One of the important problems related to underground storage of cryogenic material is to prevent leakage of liquid and gas from containment system to the rock mass caused by tensile failures due to shrinkage of the rock mass around the caverns (Monsen & Barton, 2001). So a new concept of storing liquefied natural gas (LNG) in a lined rock cavern with containment system has been developed. It consists of protecting the host rock against the extremely low temperature and providing a liquid and gas tight liner. Moreover, moderated and controlled frost development in the surrounded rock mass contributes to create an ice ring, which acts as a secondary barrier against any possible leakage. To demonstrate the feasibility of this concept and validate numerical modeling and calculations, a pilot plant was constructed in the Daejeon Science Complex in 2003. A pilot test using liquefied nitrogen was conducted from January through August 2004. In this paper, measured in-situ rock mass responses from the operation of Daejeon LNG storage pilot cavern are presented and analyzed on rock mechanical point of view. Overall monitored results from the pilot experiences confirmed that construction and operation of underground LNG storage in lined rock caverns are technically feasible from rock mechanical point of view. The Daejeon LNG storage pilot cavern represents a further important step in the validation of the technology of lined LNG underground storage. Even though the cavern was small, this project will permit to address the potential and critical points for construction, start up and operation of such new technology.