PUMPING OF LIQUIFIED GAS

• Main Author: PEVZNER, BORIS
• Format: Patent
• Language: English; French
• Published: 18.07.1995
• Edition: 5
• Subjects: BLASTING; FILLING VESSELS WITH, OR DISCHARGING FROM VESSELS, COMPRESSED,LIQUEFIED, OR SOLIDIFIED GASES; FIXED-CAPACITY GAS-HOLDERS; HEATING; LIGHTING; MECHANICAL ENGINEERING; NON-POSITIVE DISPLACEMENT PUMPS; PIPE-LINE SYSTEMS; PIPE-LINES; POSITIVE DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS; STORING OF DISTRIBUTING GASES OR LIQUIDS; VESSELS FOR CONTAINING OR STORING COMPRESSED, LIQUEFIED ORSOLIDIFIED GASES; WEAPONS

Method and apparatus for supplying from a vessel to a pump liquified gas with subcooling so as to avoid cavitation during pumping. A supply conduit supplies liquified gas from the vessel bottom to a pump sump which envelops the flowpath elements of a pump and the pump suction. A return conduit returns vapor and excess liquified gas from the sump to the bottom of the vessel. Heating means, preferably heat leak into the return conduit, reduces the density of the fluid in the return conduit thereby increasing the rate of liquified gas flow in the supply conduit and reducing its temperature rise enroute to the pump. Further subcooling is secured by locating the intake to the supply conduit remote from a wall of the vessel in a cooler strata of liquid, and the discharge of the return conduit proximate to a wall of the vessel in a warmer strata in the vessel. The low flow friction losses in the supply and return conduits enhance the circulation rate of liquified gas in the conduits, and the short supply conduit reduces the heat leak into the liquified gas flow in the supply conduit, so that sufficient subcooling is achieved with reduced elevation of the vessel above the pump sump and reduced pressurization of the vessel compared to prior art.