Method for recovering propane and heavier hydrocarbons

Claim 1

A METHOD FOR REMOVING METHANE AND ETHANE FROM A PETROLEUM FRACTION CONTAINING HYDROCARBONS BOILING WITHIN THE RANGE OF GASOLINE, WHICH COMPRISES INTRODUCING SAID PETROLEUM FRACTION INTO A HIGH PRESSURE FRACTIONATING ZONE AT THE POINT TO MINIMUM TEMPERATURE THEREIN, PASSING THE OVERHEAD GAS EMITTED FROM SAID HIGH PRESSURE ZONE TO A CONDENSING ZONE WHEREIN HIGH BOILING COMPONENTS OF SAID OVERHEAD GAS ARE LIQUEFIED, RECYCLING SAID LIQUEFIED COMPONENTS AS REFLUX TO SAID HIGH PRESSURE FRACTIONATING ZONE, EXPANDING REMAINING GAS WITH RESULTANT COOLING THEREOF, FLOWING THE RESULTING COOLED GAS IN INDIRECT HEAT EXCHANGE WITH THE AFOREMENTIONED CONDENSING ZONE SERVING TO COOL THE SAME, PASSING THE LIQUID BOTTOMS PRODUCT OF SAID HIGH PRESSURE FRACTIONATING ZONE INTO A SECOND FRACTIONATING ZONE MAINTAINED AT A PRESSURE OF AT LEAST 200 POUNDS PER SQUARE INCH LESS THAN THE PRESSURE OF SAID HIGH PRESSURE FRACTIONATING ZONE, THE MINIMUM PRESSURE OF SAID SECOND FRACTIONATING ZONE IN TURN BEING ABOUT 200 POUNDS PER SQUARE INCH, WITHDRAWING THE VAPOROUS EFFLUENT OF SAID SECOND FRACTIONATING ZONE, COOLING THE SAME TO LIQUEFY THE HIGH BOILING COMPONENTS THEREOF, RECYCLING RESULTING LIQUID AS REFLUX TO SAID SECOND FRACTIONATING ZONE, COMPRESSING REMAINING VAPOR IN A TURBOCOMPRESSOR DRIVEN BY THE AFORESAID OVERHEAD GAS FROM SAID HIGH PRESSURE ZONE, CONDUCTING THE RESULTING GAS, HEATED AS A RESULT OF COMPRESSION, TO THE BOTTOM OF SAID HIGH PRESSURE FRACTIONATING ZONE, WITHDRAWING METHANE AND ETHANE AS OVERHEAD FROM SAID HIGH PRESSURE FRACTIONATING ZONE AND WITHDRAWING HEAVIER HYDROCARBONS AS BOTTOMS PRODUCT FROM SAID SECOND FRACTIONATING ZONE.

Claim 2

A METHOD FOR REMOVING METHANE AND ETHANE FROM A PETROLEUM FRACTION CONTAINING HYDROCARBONS BOILING WITHIN THE RANGE OF GASOLINE, WHICH COMPRISES INTRODUCING SAID PETROLEUM FRACTION INTO A HIGH PRESSURE FRACTIONATING ZONE AT THE POINT TO MINIMUM TEMPERATURE THEREIN, PASSING THE OVERHEAD GAS EMITTED FROM SAID HIGH PRESSURE ZONE TO A CONDENSING ZONE WHEREIN HIGH BOILING COMPONENTS OF SAID OVERHEAD GAS ARE LIQUEFIED, RECYCLING SAID LIQUEFIED COMPONENTS AS REFLUX TO SAID HIGH PRESSURE FRACTIONATING ZONE, EXPANDING REMAINING GAS WITH RESULTANT COOLING THEREOF, FLOWING THE RESULTING COOLED GAS IN INDIRECT HEAT EXCHANGE WITH THE AFOREMENTIONED CONDENSING ZONE SERVING TO COOL THE SAME, PASSING THE LIQUID BOTTOMS PRODUCT OF SAID HIGH PRESSURE FRACTIONATING ZONE INTO A SECOND FRACTIONATING ZONE MAINTAINED AT A PRESSURE OF AT LEAST 200 POUNDS PER SQUARE INCH LESS THAN THE PRESSURE OF SAID HIGH PRESSURE FRACTIONATING ZONE, THE MINIMUM PRESSURE OF SAID SECOND FRACTIONATING ZONE IN TURN BEING ABOUT 200 POUNDS PER SQUARE INCH, WITHDRAWING THE VAPOROUS EFFLUENT OF SAID SECOND FRACTIONATING ZONE, COOLING THE SAME TO LIQUEFY THE HIGH BOILING COMPONENTS THEREOF, RECYCLING RESULTING LIQUID AS REFLUX TO SAID SECOND FRACTIONATING ZONE, COMPRESSING REMAINING VAPOR IN A TURBOCOMPRESSOR DRIVEN BY THE AFORESAID OVERHEAD GAS FROM SAID HIGH PRESSURE ZONE, CONDUCTING THE RESULTING GAS, HEATED AS A RESULT OF COMPRESSION, TO THE BOTTOM OF SAID HIGH PRESSURE FRACTIONATING ZONE, WITHDRAWING METHANE AND ETHANE AS OVERHEAD FROM SAID HIGH PRESSURE FRACTIONATING ZONE AND WITHDRAWING HEAVIER HYDROCARBONS AS BOTTOMS PRODUCT FROM SAID SECOND FRACTIONATING ZONE.