Process of and apparatus for lowtemperature decomposition of gas mixtures

Claim 1

PROCESS FOR THE SEPARATION OF A GAS MIXTURE COMPRISING A HIGHER BOILING COMPONENT AND A LOWER BOILING COMPONENT, THE CONTENT OF ONE COMPONENT BEING GREATER THAN THAT OF ANY OTHER COMPONENT, BY LOW TEMPERATURE RECTIFICATION IN A MAIN RECTFYING COLUMN CONSISTING OF AT LEASE THREE RECTIFYING STAGES CONNECTED IN SUCCESSION, TRANSFERRING THE HEAT SET FREE BY THE CONDENSATION OF THE GAS FLOWING INTO THE TOP OF A LOWER STAGE BEING UNDER HIGHER PRESSURE TO THE SUMP OF A HIGHER STAGE BEING UNDER LOWER PRESSURE FOR EVAPORATING THE SUMP LIQUID BOILING THEREIN, AND AN AUXILIARY RECTIFYING COLUMN, WHICH COMPRISES FEEDING THE GAS MIXTURE TO BE SEPARATED INTO THE FIRST STAGE UNDER THE HIGHEST PRESSURE, AT A POINT BETWEEN HEAD AND FOOT OF SAID STAGE CORRESPONDING TO ITS COMPOSITION AND EFFECTING A FIRST STAGE SEPARATION, WITH-DRAWING A FIRST LIQUID PART OF THAT COMPONENT WHICH WAS PRESENT IN LARGER VOLUME IN THE ORIGINAL GAS MIXTURE FROM THE FIRST STAGE AS FIRST PURE PRODUCT, WITH-DRAWING IMPURE PRODUCT FROM SAID FIRST STAGE AND CONDUCTING IT INTO THE SECOND STAGE BEING UNDER LOWER PRESSURE BETWEEN HEAD AND FOOT OF SAID STAGE, WITH-DRAWING A SECOND LIQUID PART OF SAID LARGER-VOLUMED COMPONENT FROM SAID SECOND STAGE AS A FURTHER PORTION OF SAID FIRST PURE PRODUCT, WITHDRAWING IMPURE PRODUCT FROM SAID SECOND STAGE AND CONDUCTING IT TO A SUCCEEDING STAGE WHICH IS MAINTAINED AT