Patent ID: 8544296
Filing Date: 2013-10-01
Classification: C10L,F17D

Abstract:
1. A compressed gas pressure letdown apparatus to maintain an essentially constant outlet temperature and a lower outlet pressure of an incoming external high pressure gas stream irrespective of an available heat capacity, comprising: a two-way cryogenic expansion valve receiving the incoming external gas stream at a high inlet pressure via a first pipe, said expansion valve for decreasing a pressure of the gas stream, cooling the gas stream to a cryogenic temperature as a by-product of the pressure decrease; a heat exchanger for heating said cooled gas stream above the cryogenic temperature received from the expansion valve via a second cryogenic pipe using heat from a variable heat source with indeterminate available heat capacity; a temperature-measuring device disposed after the expansion valve for measuring a temperature signal of the gas stream received via a third pipe; and a two-way non-cryogenic control valve, disposed immediately after the heat exchanger and leading to an outlet of the apparatus, said control valve automatically actuated by the temperature signal received from said temperature-measuring device to control a flow-rate of the gas stream through the expansion valve and the heat exchanger, wherein the flow-rate is controlled automatically to adjust a residence time of the gas stream in the heat exchanger depending on the available heat capacity in the heat exchanger to maintain the essentially constant outlet temperature of the gas stream at the lower outlet pressure at the outlet to the apparatus.