Process for obtaining a gas fraction which is highly rich in carbon monoxide from a carbon monoxide containing gas mixture

Claim 1

A PROCESS FOR OBTAINING A GAS FRACTION WHICH IS HIGHLY RICH IN CARBON MONOXIDE FROM A CRUDE, COMPRESSED GAS MIXTURE, CONSISTING OF A MAJOR PROPORTON OF HYDROGEN AND A MINOR PROPORTION OF CARBON MONOXIDE, TO GETHER WITH IMPURITIES SUCH AS METHANE, ARGON, OXYGEN NITROGEN AND THE LIKE, COMPRISING THE STEPS OF COOLING THE COMPRESSED, CRUDE MIXTURE TO LOW TEMPERATURES TO FORM A SUPERCOOLED CRUDE MIXTURE IN A FIRST HEAT-EXCHANGE WITH A SUBSTANTIALLY PURE NITROGEN AND HYDROGEN MIXTURE, IN A SECOND HEAT-EXCHANGE WITH EVAPORATING RICH CARBON MONOXIDE-NITROGEN LIQUID FRACTION, AND IN A THIRD HEATEXCHANGE WITH AN EVAPORATING POOR CARBON MONOXIDENITROGEN LIQUID FRACTION, COLLECTING A CONDENSATE CONSISTING ESSENTIALLY OF CARBON MONOXIDE FROM SAID SUPERCOOLED, CRUDE MIXTURE, SUPPLYING SAID CRUDE GAS MIXTURE AND LIQUID NITROGEN TO OPPOSITE ENDS OF A WASHING COLUMN