Recovery of natural gas liquids, helium concentrate, and pure nitrogen

Claim 1

A METHOD FOR THE RECOVERY OF NATURAL GAS LIQUIDS FROM A NATURAL GAS CONTAINING HELIUM WHICH COMPRISES COOLING SAID GAS UNDER PRESSURE, SEPARATING FROM SAID GAS AS IT IS BEING COOLED A C3-RICH FRACTION AND PASSING SAID FRACTION IN HEAT EXCHANGE RELATIONSHIP WITH THE INCOMING NATURAL GAS, THEN WHEN THE NATURAL GAS HAS BEEN FURTHER COOLED SEPARATING THEREFROM A STREAM CONTAINING A LARGE PROPORTION OF METHANE AND A SMALLER PROPORTION OF NITROGEN, SEPARATING FROM SAID METHANE AND NITROGEN CONTAINING STREAM A STREAM CONTAINING A SUBSTANTIAL PROPORTION OF METHANE AND A REDUCED PROPORTION OF NITROGEN, OBTAINING A STREAM CONTAINING AN INCREASED PROPORTION OF NITROGEN BUT CONTAINING METHANE, PASSING SAID STREAM CONTAINING AN INCREASED PROPORTION OF NITROGEN TO A NITROGEN PURIFICATION STEP, THEREIN RECOVERING NITROGEN FROM WHICH A SUBSTANTIALLY PROPORTION OF THE METHANE HAS BEEN REMOVED, RECOVERING METHANE FROM SAID STEP, COOLING FURTHER THE REMAINDER OF THE COOLED AND PARTIALLY CONDENSED NATURAL GAS, OBTAINING THEREFROM A HELIUM CONCENTRATE, PASSING SAID HELIUM CONCENTRATE IN HEAT EXCHANGE RELATIONSHIP TO THE INCOMING NATURAL GAS, OBTAINING UPON SEPARATION OF THE HELIUM CONCENTRATE FROM THE COOLED AND CONDENSED NATURAL GAS A GAS CONTAINING ESSENTIALLY NITROGEN AND METHANE WHICH IS SUITABLE FOR FUEL AND PASSING SAID GAS ALSO INTO HEAT EXCHANGE RELATIONSHIP WITH THE INCOMING NATURAL GAS.

Claim 2

A METHOD FOR THE RECOVERY OF NATURAL GAS LIQUIDS FROM A NATURAL GAS CONTAINING HELIUM WHICH COMPRISES COOLING SAID GAS UNDER PRESSURE, SEPARATING FROM SAID GAS AS IT IS BEING COOLED A C3-RICH FRACTION AND PASSING SAID FRACTION IN HEAT EXCHANGE RELATIONSHIP WITH THE INCOMING NATURAL GAS, THEN WHEN THE NATURAL GAS HAS BEEN FURTHER COOLED SEPARATING THEREFROM A STREAM CONTAINING A LARGE PROPORTION OF METHANE AND A SMALLER PROPORTION OF NITROGEN, SEPARATING FROM SAID METHANE AND NITROGEN CONTAINING STREAM A STREAM CONTAINING A SUBSTANTIAL PROPORTION OF METHANE AND A REDUCED PROPORTION OF NITROGEN, OBTAINING A STREAM CONTAINING AN INCREASED PROPORTION OF NITROGEN BUT CONTAINING METHANE, PASSING SAID STREAM CONTAINING AN INCREASED PROPORTION OF NITROGEN TO A NITROGEN PURIFICATION STEP, THEREIN RECOVERING NITROGEN FROM WHICH A SUBSTANTIALLY PROPORTION OF THE METHANE HAS BEEN REMOVED, RECOVERING METHANE FROM SAID STEP, COOLING FURTHER THE REMAINDER OF THE COOLED AND PARTIALLY CONDENSED NATURAL GAS, OBTAINING THEREFROM A HELIUM CONCENTRATE, PASSING SAID HELIUM CONCENTRATE IN HEAT EXCHANGE RELATIONSHIP TO THE INCOMING NATURAL GAS, OBTAINING UPON SEPARATION OF THE HELIUM CONCENTRATE FROM THE COOLED AND CONDENSED NATURAL GAS A GAS CONTAINING ESSENTIALLY NITROGEN AND METHANE WHICH IS SUITABLE FOR FUEL AND PASSING SAID GAS ALSO INTO HEAT EXCHANGE RELATIONSHIP WITH THE INCOMING NATURAL GAS.