Method and means for controlling particle circulation rate in a dilute phase processing system

Claim 1

IN A FLUIDIZED PARTICLE PROCESSING SYSTEM WHEREIN A REACTANT STREAM EFFECTS A FLUIDIZED CONTACT WITH SUBDIVIDED PARTICLES IN ONE CONTACT ZONE AND RESULTING CONTACTED PARTICLES DESCEND IN A MOVING COLUMN TO ENTER INTO A SECOND CONTACT ZONE FOR FLUIDIZED CONTACT WITH A DIFFERENT REACTANT STREAM, AND PARTICLES FROM SUCH SECOND ZONE ARE RETURNED IN A DESCENDING MOVING COLUMN FLOW TO THE FIRST CONTACT ZONE, THE IMPROVED METHOD FOR CONTROLLING THE RATE OF PARTICLE CIRCULATION BETWEEN ZONES WITHOUT THE USE OF A FLOW CONTROL VALVE IN THE PATH OF THE PARTICLES, WHICH COMPRISES, INTRODUCING SUCH PARTICLES FROM THE LOWER END OF ONE OF SAID MOVING COLUMNS INTO AN ENLARGED SURGE ZONE POSITIONED AHEAD OF AND CONNECTIVE WITH THE OTHER OF SAID CONTACT ZONES AND HAVING VENT MEANS PROVIDED WITH VALVE CONTROL MEANS, AND ADJUSTABLY INCREASING AND RELIEVING PRESSURE ON SAID SURGE ZONE BY SAID VALVE CONTROL MEANS TO REGULATE FLUISTATIC PRESSURE THEREIN AND PROVIDE A DIRECT CONTROL OF THE RATE OF CIRCULATION OF PARTICLES FROM THE LATTER TO SAID CONNECTING CONTACT ZONE AND IN SAID SYSTEM WITHOUT CHANGING THE RATE OF INTRODUCTION OF A REACTANT STREAM THERETO.