Treatment of waste liquors

Claim 1

IN A CHEMICAL RECOVERY UNIT WHICH INCLUDES A FURNACE AND A BOILER AND WHEREIN LIQUOR OBTAINED IN THE CHEMICAL DIGESTION PROCESS OF CELLULOSE BEARING MATERIAL IS INTRODUCED INTO THE FURNACE OF THE UNIT AND BURNED WITH A PORTION OF THE HEAT THAT IS EVOLVED BEING IMPARTED TO THE BOILER TO GENERATE STEAM THE PROCESS COMPRISING CONCENTRATING THE LIQUOR PRIOR TO INTRODUCING IT INTO THE FURNACE BY FIRST PASSING IT THROUGH A MULTIPLE EFFECT EVAPORATOR, THEREAFTER PASSING IT THROUGH A HOUSING, PASSING AIR IN INDIRECT HEAT EXCHANGE RELATION WITH THE COMBUSTION GASES ISSUING FROM THE BOILER THEREBY HEATING SAID AIR AND DECREASING THE TEMPERATURE OF SAID GASES, CONVEYING THIS HEATED AIR THROUGH SAID HOUSING AND CONTACTING THE LIQUOR THEREIN WITH SAID AIR THEREBY EVAPORATING MOISTURE THEREFROM AND FURTHER CONCENTRATING THE SAME, INTRODUCING THE LIQUOR FROM THIS HOUSING INTO THE FURNACE AND INTRODUCING AT LEAST A PORTION OF THE AIR CONVEYED THROUGH THE HOUSING INTO THE FURNACE AS COMBUSTION SUPPORTING AIR FOR SAID LIQUOR.