Process and apparatus for purifying and separating compressed gas mixtures

Claim 1

A PROCESS FOR THE LOW-TEMPERATURE RECTIFICATION OF WATER AND CARBON DIOXIDE IMPURITY-CONTAINING AIR INCLUDING THE STEPS OF PRIOVIDING AN AIR STREAM AT AN INLET PRESSURE BELOW 150 P.S.I., PASSING SUCH STREAM TO A REVERSIBLE HEAT EXCHANGE ZONE, PARTIALLY COOLING THE AIR STREAM IN SUCH ZONE TO AT LEAST -80*C. AND REMOVING THE WATER IMPURITY BY DEPOSITION IN HEAT EXCHANGE ZONE, DIVIDING PARTIALLY COOLED AIR STREAM INTO MAJOR AND MINOR PORTIONS, WITHDRAWING THE MINOR PORTION FROM SAID REVERSIBLE HEAT EXCHANGE ZONE AND FURTHER COOLING SUCH PORTION BY HEAT EXCHANGE WITH A FIRST COLDER FLUID TO A TEMPERATURE SLIGHTLY ABOVE THE DEPOSITION POINT OF CARBON DIOXIDE SAID INLET PRESSURE, REMOVING THE DISSOLVED CARBON DIOXIDE IMPURITY FROM THE FURTHER COOLED MINOR PORTION OF SAID AIR STREAM NY ADSORPTION, DIVERTING AND STILL FURTHER COOLING A REGULATED PART OF SUCH PORTION BY HEAT EXCHANGE WITH SAID FIRST COLDER FLUID, REMOVING AT LEAST MOST OF THE CARBON DIOXIDE IMPURITY FROM THE PARTIALLY COOLED MAJOR PORTION OF SAID AIR STREAM BY FURTHER COOLING AND DEPOSITION THEREOF IN SAID REVERSIBLE HEAT EXCHANGE ZONE, PASSING AT LEAST PART OF THE FURTHER COOLED MAJOR PORTION AND THE STILL FURTHER COOLED REGULATED PART OF SAID MINOR PORTION OF THE AIR STREAM TO A RECTIFICATION ZONE FOR SEPARATION INTO AIR COMPONENTS, REMOVING THE WATER AND CARBON DIOXIDE IMPURITIES DEPOSITED IN SAID HEAT EXCHANGE ZONE BY PASSING AT LEAST PART OF THE SEPARATED AIR COMPONENTS THROUGH THE ZONE AND EVAPORATING SUCH IMPURITIES THEREIN FOR DISCHARGE FROM SUCH ZONE, WITHDRAWING A CARBON DIOXIDE-FREER GAS PORTION FROM SAID RECTIFICATION ZONE AND DIVIDING SUCH PORTION INTO FIRST AND SECOND PARTS, PREHEATING SAID FIRST PART OF SUCH WITHDRAWN GAS BY CONSECUTIVE HEAT EXCHANGE WITH THE DIVERTED PART OF THE MINOR PORTION OF SAID AIR STREAM AND THE WITHDRAWIN MINOR PORTION RESPECTIVELY AS SAID FIRST COLDER FLUID, MIXING THE PREHEATED FIRST PART AND THE SECOND PART OF THE WITHDRAWIN GAS PORTION, COMBINING SUCH MIXED STREAM WITH THE UNDIVERTED PART OF THE FURTHER COOLED CARBON DIOXIDE-FREE MINOR PORTION OF SAID AIR STREAM TO FROM A WORK EXPANSION INLET STREAM, AND EXPANDING SUCH STREAM TO LOWER PRESSURE WITH THE PRODUCTION OF EXTERNAL WORK.