Pebble heater apparatus and method of regenerating pebbles therein

Claim 1

AN IMPROVED METHOD OF REGENERATING AND HEATING PEBBLES WHICH ARE CONTAMINATED WITH SURFACE DEPOSITS OF CARBON, WHICH COMPRISES; INTRODUCING SAID PEBBLES INTO A PEBBLE HEATING ZONE; LATERALLY INTRODUCING AN OXYGEN-CONTAINING FLUEGAS INTO THE UPPER PORTION OF SAID HEATING ZONE AT A PLURALITY OF POINTS AND CONTACTING SAID PEBBLES WITH SAID FLUE-GAS WHEREBY CARBON IS BURNED FROM SAID PEBBLES IN SAID UPPER PORTION OF SAID HEATING ZONE; INTRODUCING FUEL-GAS INTO A PLURALITY OF MIXING ZONES; INTRODUCING AN OXYGENCONTAINING FLUE-GAS INTO SAID MIXING ZONES; MIXING SAID FUEL-GAS AND SAID LAST-MENTIONED FLUEGAS IN SAID MIXING ZONES; LATERALLY INTRODUCING RESULTING COMBUSTIBLE MIXTURES INTO THE LOWER PORTION OF SAID HEATING ZONE AT A PLURALITY OF POINTS AT A VELOCITY GREATER THAN THE VELOCITY OF FLAME PROPAGATION OF THE SAID MIXTURES WHEREBY THE MIXTURE DOES NOT BURN UNTIL IT CONTACTS SAID PEBBLES IN SAID HEATING ZONE, SAID COMBUSTIBLE MIXTURES DIRECTLY CONTACTING SAID PEBBLES; BURNING SAID RESULTING COMBUSTIBLE MIXTURES WITHIN THE INTERSTICES OF THE SURFACE OF SAID PEBBLES; WITHDRAWING PRODUCTS OF COMBUSTION FROM SAID HEATING ZONE AT A PLURALITY OF POINTS IN THE UPPER AND LOWER PORTIONS OF SAID HEATING ZONE; INTRODUCING AN OXYGEN-CONTAINING GAS INTO SAID WITHDRAWN PRODUCTS OF COMBUSTION; WITHDRAWING A PROTION OF THE RESULTING MIXTURE OF FLUE-GAS AND AN OXYGEN-CONTAINING GAS FROM THE SYSTEM; RECYCLING A PORTION OF SAID RESULTING MIXTURE TO SAID MIXING ZONES; AND WITHDRAWING HEATED PEBBLES FROM THE BOTTOM PORTION OF SAID HEATING ZONE.