| abstract |
1,180,416. Liquefied gas storage chambers. INSTITUTE OF GAS TECHNOLOGY. 14 Feb., 1967 [14 Feb., 1966 (3)], No. 7040/67. Heading F4P. The floor, sides and roof of an excavated underground rock cavern 8, Fig. 3, at the bottom end of an inclined adit 3 for storing liquid methane at atmospheric pressure are first sealed at 101, 121, Fig. 4, against inflow of water, the roof and sides are then lined with foam-in-place insulation material 103, e.g. polyurethane which in turn is lined by layers 105, 106 of rigid polyurethane foam panels whilst the floor is lined by layers 107a, 106a formed of rigid polyurethane panels, and the roof sides and floor are then sealed by an impermeable barrier layer 111, e.g. of aluminum and finally the adit is closed at a point above the stored liquid level by a vapour barrier means 6 through which pass service lines. Abutting edges of the panels of layers 105, 107a are sealed by non-setting mastic whereon abutting edges of the panels of layers 106, 106a are sealed by flexible foam 113, Fig. 5, and by flexible tape. The barrier 6 comprises a doublewalled steel frame 211, Fig. 10, bolted to a concrete frame 207 set in the walls, floor and roof of the adit, and an access opening 219 in frame 211 is closed by a removable cover 223. In operation air is displaced from the cavern by inert gas delivered from a source 25 through initial cool-down spray lines 26 and the liquid fill line 30, whilst return purge gas is exhausted through a liquid withdrawal line 38 and a vapour return line 32. Initial liquid injection is through lines 26 and nozzles 28 and displaced gas returning through line 32 is flared at 48 until said return gas comprises pure methane after which the return gas is either re-liquefied at 50 or delivered to a consumer line 49. When cooldown is completed liquid methane is fed to the cavern through fill line 30 and may be withdrawn by a pump 56 discharging through a line 38 into a vaporizer 35. |