| 摘要 |
An underground storage reservoir for LNG or other fluids at cryogenic temperatures comprises an underground cavern (10), usually insulated, an inner circulation system surrounding the cavern and comprising a plurality of passages (18 to 22) and an outer circulation system comprising a plurality of ducts (11 to 15). A heat exchange gas is circulated through the inner circulation system so that the temperature of the cavern wall and the ground immediately surrounding the wall is maintained within a predetermined temperature range higher than the temperature of the stored fluid and the critical temperature at which the ground cracks. A heat exchange gas is also circulated through the outer circulation system so that a frozen zone is established and maintained in the ground encircling the inner circulation system. The invention then involves adjusting the pressures in the inner and outer circulation systems so that gas is caused to diffuse outwards through the ground towards the outer circulation system in counterflow to water vapour migrating inwards, so that the movement of water vapour is halted or reversed. <IMAGE> |
