Method and apparatus for Liquefying gas with several expansions of the work load AS Refrigerant and the Cycle of Air Separation incorporating the same.

摘要

A method for Liquefying gas of low Boiling Point, in which the gas is compressed under High PressureIs cooled in a Heat Exchange structure, and expands isoentu00e1lpicamente to condense a portion of it to a Liquid.The Liquid is separated from the waste Gas and the waste gas is used for Cooling The Heat Exchange structure and then recirculated.A portion of the gas is compressed to a pressure Intermediate between High and low pressures.Isoentru00f3picamente expands to a First temperature and is used for Cooling a portion of the structure of relatively Hot Heat Exchange and then recirculated.A portion of the High Pressure gas isoentru00f3picamente expands to a Second temperature and is used for Cooling a portion, relatively Cold,The structure of Heat Exchange and then again isoentru00f3picamente expands to a Third temperature at low pressure and return through the Heat Exchange structureCool It and then recirculated. The First temperature and the second temperature is higher than the second temperature is greater than the Third temperature.The nitrogen gas is preferably.The cycle can be part of an air Separation Unit, whose product of Nitrogen, Low PressureIt integrates the liquefaction Cycle and the product nitrogen High Pressure gas blends with the Cycle of low pressure.