Method for low temperature separation of gaseous mixtures

Claim 1

METHOD OF SEPARATING GASEOUS MIXTURES INTO COMPONENT GASES IN A LOW TEMPERATURE FRCTIONATING OPERATION EMPLOYING A PLURALITY OF FRACTIONATING ZONES INCLUDING PRELIMINARY SEPARATION IN A FIRST FRACTIONATING ZONE UNDER SUPERATMOSPHERIC PRESSURE PRODUCING FIRST GASEOUS LOW BOILING POINT FRACTION AND FIRST LIQUID HIGH BOILING POINT FRACTION AND A FURTHER SEPARATION IN A SECOND FRACTIONATING ZONE UNDER RELATIVELY LOW PRESSURE PRODUCING SECOND GASEOUS LOW BOILING POINT FRACTION AND SECOND LIQUID HIGH BOILING POINT FRACTION, COMPRISING THE STEPS OF PROVIDING COOL GASEOUS MATERIAL UNDER SUPERATMOSPHERIC PRESSURE FROM COMPRESSED GASEOUS MIXTURE TO BE SEPARATED, THE GASEOUS MATERIAL INCLUDING COMPONENTS OF THE GASEOUS MIXTURE WITH THE PERCENTAGE OF HIGH BOILING POINT COMPONENT BEING LESS THAN THE PERCENTAGE OF HIGH BOILING POINT COMPONENT OF THE FIRST LIQUID HIGH BOILING POINT FRACTION AND GREATER THAN THE PERCENTAGE OF HIGH BOILING POINT COMPONENT OF THE FIRST GASEOUS LOW BOILING POINT FRACTION, PERFORMING A FIRST CONDENSING-EVAPORATING STEP INCLUING ESTABLISHING HEAT EXCHANGE BETWEEN COLD GASEOUS MATERIAL AND SECOND LIQUID HIGH BOILING POINT FRACTION TO VAPORIZE SECOND LIQUID HIGH BOILING POINT FRACTION AND PROVIDE FURTHER COOLED GASEOUS MATERIAL, THE FIRST CONDENSING-EVAPORATING STEP INCLUDING UTILIZATION OF VAPORIZED SECOND LIQUID HIGH BOILING POINT FRACTION AS REBOIL FOR THE SECOND FRACTIONATING ZONE AND UTILIZATION OF FURTHER COOLED GASEOUS MATERIAL AS FEED IN AT LEAST ONE OF THE FRACTIONATING ZONES, PERFORMING A SECOND CONDENSINGEVAPORATING STEP INCLUDING ESTABLISHING HEAT EXCHANGE BETWEEN FIRST GASEOUS LOW BOILING POINT FRACTION AND LIQUID MATERIAL OF THE OPERATION TO LIQUEFY FIRST GASEOUS LOW BOILING POINT FRACTION AND VAPORIZE LIQUID MATERIAL, THE LIQUID MATERIAL BEING UNDER LOW PRESSURE RELATIVE TO THE FIRST GASEOUS LOW BOILING POINT FRACTION AND INCLUDING COMPONENTS OF THE GASEOUS MIXTURE WITH THE PERCENTAGE OF THE HIGH BOILING POINT COMPONENT BEING GREATER THAN THE PERCENTAGE OF HIGH BOILING POINT COMPONENT OF THE FIRST LIQUID HIGH BOILING POINT FRACTION AND LESS THAN THE PERCENTAGE OF THE HIGH BOILING POINT COMPONENT OF THE SECOND LIQUID HIGH BOILING POINT FRACTION, AND UTILIZING LIQUEFIED FIRST LOW BOILING POINT FRACTION AS REFLUX FOR THE FIRST AND SECOND FRACTIONATING ZONES.