Regeneration of contact material

Claim 1

IN A PROCESS FOR REGENERATION OF A SOLID PARTICLE-FORM CONTACT MASS MATERIAL WHICH HAS BECOME SPENT BY DEPOSITION OF A CARBONACEOUS DEPOSIT THEREON AND WHICH EXISTS AT A TEMPERATURE SUITABLE FOR INITIATING COMBUSTION OF SAID DEPOSIT, WHICH PROCESS COMPRISES: PASSING SAID PARTICLEFORM SOLID MATERIAL DOWNWARDLY THROUGH A BURNING ZONE AS A SUBSTANTIALLY COMPACT COLUMN OF GRAVITATING PARTICLES, INTRODUCING A STREAM OF COMBUSTION AIR INTO THE BURNING ZONE, SPLITTING THE COMBUSTION AIR STREAM INTO TWO STREAMS AT A POINT INTERMEDIATE THE ENDS OF THE COMPACT COLUMN OF PARTICLES IN THE BURNING ZONE, ONE STREAM OF COMBUSTION AIR PASSING UPWARDLY THROUGH THE COLUMN TO BURN OFF PART OF THE CONTAMINANT ON THE GRAVITATING PARTICLE-FORM MATERIAL AND BE WITHDRAWN FROM THE UPPER SECTION OF THE COLUMN, THE SECOND STREAM OF COMBUSITION AIR PASSING DOWNWARDLY THROUGH THE COLUMN TO BURN OFF ADDITIONA AMOUNTS OF CONTAMINANT FROM THE MATERIAL AND BE WITHDRAWN FROM THE COLUMN INTO SUBSTANTIALLY PARTICLE-FREE FLUE-GAS WITHDRAWAL REGIONS IN THE LOWER SECTION OF THE COLUMN, COOLING THE PARTICLE-FORM MATERIAL AND THE DOWNWARDLY PASSING SECOND STREAM OF COMBUSTION AIR AND RESULTING FLUE GAS IN AN INDIRECT HEAT EXCHANGE ZONE LOCATED ABOVE THE PARTICLE-FREE FLUE-GAS WITHDRAWAL REGIONS, INTRODUCING A FIRST STREAM OF COOLING AIR DIRECTLY INTO THE PARTICLE FREE FLUE-GAS WITHDRAWAL REGIONS, WITHDRAWING THE MIXTURE OF FLUE-GAS AND COOLING AIR FROM THE PARTICLE-FREE FLUE-GAS WITHDRAWAL REGIONS AND WITHDRAWING THE CONTACT MATERIAL FROM THE BOTTOM OF THE COMPACT COLUMN; THE IMPROVEMENT COMPRISING INTRODUCING A SECOND STREAM OF COOLING AIR DIRECTLY INTO THE COLUMN OF PARTICLE-FORM CONTACT MATERIAL AT A POINT ABOVE SAID PARTICLE-FREE FLUE-GAS WITHDRAWAL REGIONS AND BELOW SAID INDIRECT HEAT EXCHANGE ZONE TO ADMIX SAID SECOND STREAM OF COOLING AIR DIRECTLY WITH THE DOWNWARDLY PASSING SECOND STREAM OF COMBUSTION AIR AND RESULTING FLUE-GAS AND WITH SAID PARTICLE-FORM CONTACT MATERIAL TO COOL SAID DOWNWARDLY PASSING SECOND STREAM OF COMBUSTION AIR AND RESULTING FLUE-GAS AND SAID PARTICLE-FORM CONTACT MATERIAL TO A TEMPERATURE AT WHICH AFTERBURNING WILL NOT OCCUR, TO THUS ELKIMINATE THE POSSIBILITY OF AFTERBURNING ADJACENT THE PARTICLE-FREE FLUE-GAS WITHDRAWAL REGIONS.