Liquid level control

Claim 1

A MIXED PHASE ISOMERIZATION PROCESS FOR THE ISOMERIZATION OF NORMAL BUTANE TO ISOBUTANE COMPRISING INTRODUCING LIQUID NORMAL BUTANE INTO AN EVAPORATING ZONE CONTAINING PACKING AND AN ALUMINUM HALIDE CATALYST DEPOSITED ON SAID PACKING, SAID LIQUID BUTANE BEING INTRODUCED TO SAID ZONE AT A TEMPERATURE AND AT A RATE SELECTED SO THAT WHILE RAPID EVAPORATION OCCURS TO LIQUID LEVEL WILL GRADUALLY RISE IN SAID ZONE, AND ARRESTING THE RISE OF SAID LIQUID LEVEL BY A FORMING A BARRIER OF A SUPERHEATED VAPOR IN SAID ZONE AT A TEMPERATURE IN EXCESS OF THE BOILING POINT OF SAID LIQUID AT A POINT SPACED ABOVE SAID DESIRED LIQUID LEVEL, WHEREBY SAID LIQUID LEVEL IS CONTROLLED AT A LEVEL WHERE HEAT EXCHANGE WITH SAID SUPERHEATED VAPOR PROVIDES SUFFICIENT THERMAL UNITS TO COMPLETE THE EVAPORATION OF THE RISING LIQUID, ISOMERIZING A PORTION OF SAID NORMAL BUTANE TO ISOBUTANE IN SAID ZONE, AND REMOVING SAID ISOBUTANE AS A VAPOR.