GB1040181A - Improvements in or relating to underground gas storage tanks - Google Patents

Abstract

1,040,181. Discharging liquids by gaseouspressure. GAZ DE FRANCE. Feb. 15, 1963 [Feb. 17, 1962], No. 6312/63. Heading FIR. [Also in Division F4] Liquefied gas is stored in an underground chamber 10 which is excavated from a vertical pit 14, the access hole between the pit and the chamber being closed by a dam 16 of reinforced concrete preferably provided with a sealed manhole. Coaxial tubes 31, 32, 33 connect the chamber 10 with the ground surface 15, the tube 33 being for the supply or withdrawal of liquefied gas to or from the chamber, the space between the tubes 32 and 33 being used for the supply or withdrawal of gas to or from the spaces above the liquid surface in the chamber or for recycling the liquefied gas, and the space between the tubes 31 and 32 being used to insulate the pipes 32 and 33 from the ground. Insulation 34, Fig. 2 (not shown), e.g. polyurethane foam, may be fitted on the outside of the tube 32. The tube 31 is sealed to the ground by cement disposed around the tube, and the walls of the pit 14 are sealed by a covering layer of concrete. If the chamber 10 is in other than rock the chamber is lined with concrete, and it may also be lined with insulation, e.g. plastic foam. Prior to charging the chamber 10 it is thoroughly dried by the circulation of air of low relative humidity followed by dry nitrogen, and the pit 14 is purged by carbon dioxide gas which is placed in the pit bottom in the form of dry ice. When the chamber 10 is charged with the liquefied gas the pit 14 is simultaneously filled with water which forms an ice plug further sealing the access hole between the pit and the chamber. An auxiliary source of heat such as steam, hot water or electricity to melt the ice, and pumps for removing the resulting water, are provided in the pit 14 for use when it is necessary to gain access to the tank. More than one pit and/or chamber may be provided. Vertical metal plates may be provided to facilitate heat exchange and prevent stratification of liquid layers in the chamber or chambers. The latter may have temperature and stress gauges disposed at various points on the walls thereof and other temperature gauges may be disposed in the ground at a predetermined distance from the walls.