Low temperature separation of h2s from hydrocarbon gas

Claim 1

A LOW TEMPERATURE PROCESS FOR SEPARATING HYDROGEN SULFIDE FROM A NORMALLY GASEOUS HYDROCARBON WHICH PROCESS COMPRISES: COOLING A FEED GAS MIXTURE OF HYDROGEN SULFIDE AND AT LEAST ONE NORMALLY GASEOUS HYDROCARBON, SAID MIXTURE CONTAINING 5-90 MOLE PERCENT OF HYDROGEN SULFIDE AND METHANE GAS AS THE MAJOR HYDROCARBON CONSTITUENT AND BEING ESSENTIALLY FREE OF WATER VAPOR, TO A TEMPERATURE IN THE RANGE OF ABOUT -80*F AND ABOUT -115*F., AT AN ELEVATED PRESSURE SUBSTANTIALLY THE SAME AS THAT OF SAID FEED GAS TO OBTAIN ONLY A GASEOUS PHASE AND A LIQUID PHASE RICH IN HYDROGEN SULFIDE; SEPARATING SAID LIQUID HYDROGEN SULFIDE RICH PHASE CONTAINING DISSOLVED HYDROCARBON FROM SAID GASEOUS HYDROCARBON PHASE, SAID GASEOUS HYDROCARBON PHASE HAVING A HYDROGEN SULFIDE CONTENT LOWER THAN THAT OF SAID FEED GAS; SAID LIQUID HYDROGEN SULFIDE RICH PHASE IS THEN BROUGHT TO A TEMPERATURE IN THE RANGE OF ABOUT -50*F. AND ABOUT -120*F., AT A PRESSURE OF AT LEAST ABOUT 200 P.S.I.A., WHERE THE PRESSURE OF SAID COOLED LIQUID PHASE IS LOWER THAN THE PRESSURE OF SAID COOLED FEED GAS; SEPARATING A SECOND LIQUID HYDROGEN SULFIDE PHASE HAVING A H2S CONTENT GREATER THAN THAT OF SAID LIQUID PHASE FROM A SECOND GASEOUS HYDROCARBON PHASE AND SAID SECOND GASEOUS HYDROCARBON PHASE IS CYCLED TO FEED THE GAS AND THE COMBINED CHARGE IS THEN COOLED FOR THE FIRST SEPARATION.