| 摘要 |
914,195. Storing liquefied gases. SOHDA, Y., and SOHDA, Y. Nov. 4, 1960 [Nov. 4, 1959; Dec. 3, 1959], No. 38076/60. Class 8(2). In a container vessel assembly for the storage and transportation of liquefied gases the vessel is provided with injection means for injecting into the interior thereof both gaseous nitrogen pre-cooled to a temperature between.-17.0 ‹0. and-180‹C. and liquefied nitrogen, in the form of finely dispersed bubbles and liquid particles, whereby both the gaseous and liquefied nitrogen are brought into intimate heat exchange with a body of liquefied gas contained in the vessel for effective cooling thereof. As described with reference to Fig. 1 a container vessel 1 is substantially filled with liquefied natural gas a, the vessel having a pipe 2 for inlet and outlet of the gas. Liquefied nitrogen and gaseous nitrogen from reservoirs 9 and 7, respectively, are injected into the vessel through pipes 8 and 6 and parallel spiral coils 5 and 4, the latter having orifices therein arranged so as to inject the nitrogen gas and liquid towards each other, and towards the wall of the vessel. A fractionating chamber 13 is provided at the top of the vessel to which is connected the suction pipe 14 of a multistage refrigerant compressor 15 having a delivery pipe 18 connected to the liquefied nitrogen reservoir 9 and a delivery pipe 19 through which gaseous nitrogen is tapped from an intermediate stage of the compressor and led to the reservoir 7. The pipe 19 may be provided with a cooler and an expansion valve. Liquefied nitrogen may be supplied from the reservoir 9 through a pipe 21 to the reservoir 7 and through a pipe 23 to the fractionating chamber 13. Any natural gas reliquefied in the compressor 15 is returned to the vessel 1 through a pipe 24. The fractionating chamber 13 may be dispensed with. The spiral coils 5 and 4 may have a diminishing diameter or a course pitch as they approach the centre of the vessel; they may be replaced by a plurality of concentric coil elements or the coil for the liquefied nitrogen may be disposed within the coil for the gaseous nitrogen, the coils having concentric injecting nozzles, Figs 4 to 8 (not shown). A plurality of coil assemblies may be spaced one above the other in the vessel, Figs. 9 and 12 (not shown). The return pipe 24 may be connected to a separate vessel instead of to the vessel 1. Nets may be provided above the orifices or nozzles on the coils so as to finely disperse the nitrogen and a further net may be disposed just below the surface of the liquefied natural gas a to collect any solidified flakes of the latter so as to bring them into heat exchange contact with the rest of the natural gas. The container vessel may have a double bottom, gaseous nitrogen being supplied to the space between the bottoms for heat insulation; the inner bottom may have a plurality of fine openings preferably along its periphery so that the gaseous nitrogen can pass into the interior of the vessel. |
