GB910945A - Improvements in storing liquefied petroleum gases - Google Patents

Abstract

910,945. Storing liquefied gases. CHICAGO BRIDGE & IRON CO. April 26, 1961 [June 21, 1960], No. 15008/61. Class 8(2). A storage vessel 11 is intermittently charged with liquefied gas e.g., propane at atmospheric temperature and superatmospheric pressure e.g., 133 p.s.i. which conditions are maintained constant by withdrawing effluent through a line 12, compressing at 13, condensing at 14 and flash expanding through a valve 15 back to the vessel 11, and liquefied gas is withdrawn through valve controlled line 21 at a rate much less than the changing rate, and is flash-expanded through a valve 52 into a heat insulated storage tank 20 operating at just above atmospheric pressure and at below the boiling point of the gas. A flash evaporator 24 is included in the transfer line 21 and effluent therefrom traverses a line 26 to the second stage of a compressor 25 where it is joined by effluent from the tank 20 having traversed a line 29 and the first stage of the compressor. The combined gas streams are condensed at 31 and a first portion is returned through a heat exchanger 34 where it serves to warm liquefied gas being forced by a pump 37 into a consumer line whilst the remainder traverses a line 32 and is returned to the. evaporator 24. Off-peak storage tanks 40 are connected in parallel with tank 20 and effluent therefrom in lines 42, 43 is joined by effluent in a line 41 of tank 20 and is compressed at 46, 49, condensed at 47, 50 and the liquid fed into the evaporator 24. Rigid foam polyurethane is used to insulate the tanks 20, 40 which are provided with vents 54 and relief valves 55.