Process and apparatus for moving solid pellets in a closed circuit

Claim 1

IN THE METHOD OF MOVING PELLETS, USED AS HEAT TRANSFER AGENT, CONTINUOUSLY IN A CLOSED CIRCUIT, SAID CIRCUIT COMPRISING AN UPWARD FLOW (RISER) PART IN WHICH THE PELLETS ARE LIFTED TO A HIGHEST LEVEL, AND A DOWNWARD FLOW (DOWNCOMER) PART, IN WHICH THE PELLETS DESCEND UNDER THE EFFECT OF GRAVITY, THE UPWARD FLOW PART CONTAINING PELLETS SUSPENDED IN THE FORM OF A SLURRY IN A RISING STREAM OF A LIQUID AT SUBSTANTIALLY SUPERATMOSPHERIC PRESSURE, WHILE THE FIRST PORTION OF THE DOWNWARD FLOW PART CONTAINS PELLETS FALLING THROUGH A GAS OF SUBSTANTIALLY ATMOSPHERIC PRESSURE, THE STEPS OF PASSING THE SLURRY STREAM THROUGH TWO SEQUENTIALLY OPERATED SLUICE CHAMBERS ARRANGED IN PARALLEL AND DISPOSED AT SAID HIGHEST LEVEL, SAID SLUICE CHAMBERS BEING AT ALL TIMES COMPLETELY FILLED WITH LIQUID, SEPARATING THE PELLETS FROM THE BULK OF THE LIQUID BY SCREENING THE SLURRY WITHIN SAID CHAMBERS AND WHILE STILL UNDER SUBSTANTIALLY SUPERATMOSPHERIC PRESSURE, THEREAFTER DECOMPRESSING THE RESULTING SLURRY CONCENTRATE WITHIN SAID CHAMBERS, REMOVING THE REMAINING LIQUID FROM THE PELLETS AT SUBSTANTIALLY ATMOSPHERIC PRESSURE, AND FEEDING THE DRIED PELLETS AT SUBSTANTIALLY ATMOSPHERIC PRESSURE BACK INTO THE DOWNWARD FLOW PART.