Process and apparatus for separating helium from helium-air mixtures

Claim 1

A PROCESS FOR SEPAEATING A HELIUM-AIR GAS MIXTURE INTO ITS COMPONENTS COMPRISING THE STEPS OF PROVIDING AN INLET HELIUM-AIR GAS MIXTURE AT A FIRST PRESSURE; COOLING SUCH GAS MIXTURE TO ITS DEW POINT AT SAID FIRST PRESSURE; COCURRENTLY PARTIALLY CONDENSING THE COLLED GAS MIXTURE; SEPARATING THE PARTIALLY CONDENSED MIXTURE INTO A HELIUM-ENRICHED GAS PHASE AND A FIRST AIR-ENRICHED LIQUID PHASE; FURTHER COCURRENTLY PARTIALLY CONDENSING SAID HELIUM-ENRICHED GAS PHASE; SEPARATING THE FURTHER PARTIALLY CONDENSED MIXTURE INTO A HELIUM-FURTHER ENRICHED GAS PHASE AND A SECOND AIR-ENRICH ED LIQUID PHASE; PARTIALLY THROTTLING SAID FIRST AIR-ENRICHED LIQUID PHASE AND PASSING AT LEAST PART OF SUCH PARTIALLY THROTTLED FLUID IN HEAT EXCHANGE EITH SAID COOLED GAS MIXTURE FOR AT LEAST THE FIRST COCURRENT PARTIAL CONDENSATION STEP, THEREBY EVAPORATING SUCH FLUID; SEPARATEKY PASSING THE EVAPORATED PARTIALLY THROTTLED AIR-ENRICHED FRACTION AND SAID HELIUM FURTHER ENRICHED GAS PHASE IN COUNTERCURRENT HEAT EXCHANGE WITH THE HELIUM-AIR INLET AS MIXTURE TO PROVIDE AT LEAST PART OF THE REFRIGERATION FOR THE COOLING STEP TO THE GAS MIXTURE DEW POINT; WITHDRAWING AT AN INTERMEDIATE THERMAL LEVEL, AT LEAST PART OF THE EVAPORATED PARTIALLY THROTTLED AIR-ENRICHED FRACTION FROM SAID COUNTERCURRENT HEAT EXCHANGE WORK EXPANDING SUCH FRACTION WITH THE PODUCTION OF LOW TEMPERATURE REFRIGERATION; RETURNING THE WORK ECPANDED FRACTION COOLING OF THE INLET GAS RENT HEAT EXCHANGE FOR SEPARATE COOLING OF THE COUNTERMIXTURE; WITHDRAWING FROM THE WARM HELIUM FURTHER ENRICHED GAS PHASE AS A CRUDE HELIUM PRODUCT AND THE AIRRICHED GAS PHASE AS A CRUBE HELIUM PRODUCT AND THE AIRENRICHED FRACTION AS THE AIR PRODUCT OF THE SEPARATION.