Temperature control in a fluidized bed reactor

Claim 1

A PROCESS FOR CONTROLLING THE TEMPERATURE IN A REACTION ZONE WITHIN A FIRST FLUIDIZED BED OF PARTICULATE SOLIDS MAINTAINED AT A RELATIVELY CONSTANT LEVEL BY CONTINUOUSLY INTRODUCING SOLIDS TO AND WITHDRAWING SOLIDS FROM SAID REACTION ZONE AT A RELATIVELY CONSTANT RATE WHEREIN THE TERMPERATURE TENDS TO VARY FROM A SELECTED REACTION TEMPERATURE, WHICH COMPRISES CONTINUOUSLY WITHDRAWING A MINOR STREAM OF SOLIDS FROM SAID FIRST BED AND PASSING SAME TO AN INDIRECT HEAT EXCHANGE ZONE TO CHANGE THE TEMPERATURE OF THE WITHDRAWN SOLIDS, RETURNING A STREAM OF THE RESULTING SOLIDS TO SAID FIRST BED AT A CONSTANT RATE? MAINTAINING A SECOND FLUIDIZED BED OF SAID SOLIDS IN SAID HEAT EXCHANGE ZONE NORMALLY EXTENDING TO AND INTERMEDIATE LEVEL THEREIN, SENSING THE TEMPERATURE OF SAID FIRST BED? WHEN THE SENSED TEMPERATURE IS ABOVE THE SELECTED REACTION TEMPERATURE, INCREASING THE FLOW RATE OF SOLIDS TO SAID SECOND BED? WHEN THE SENSED TEMPERATURE IS BELOW THE SELECTED REACTION TEMPERATURE, DECREASING THE FLOW RATE OF SOLIDS TO SAID SECOND BED, PROVIDING A PROGRESSIVELY INCREASING RATE OF HEAT EXCHANGE FROM SAID INTERMEDIATE LEVEL OF SAID HEAT EXCHANGE ZONE UPWARDLY THEREFROM BY PROVIDING AN INCREASING AMOUNT OF HEAT EXCHANGE SURFACE PER UNIT OF HEIGHT SO THAT AS SAID SECOND BED LEVEL RISES, INCREASED COOLING RATE IS EFFECTED AND AS SAID SECOND BED LEVEL LOWERS, DECREASED COOLING RATE IS EFFECTED SO AS TO COMPENSATE FOR CHANGES IN TEMPERATURE FROM SAID SELECTED REACTION TEMPERATURE.