Contacting finely divided solids with gases

Claim 1

IN A PROCESS FOR TREATING FINELY DIVIDED SOLIDS WITH SEPARATE AND INDEPENDENT STREAMS OF GAS IN SEPARATE CONTACTING ZONES DISPOSED SIDE BY SIDE AND COMMUNICATING WITH EACH OTHER THROUGH A PASSAGEWAY INTERCONNECTING THE BOTTOM PORTIONS OF THE TWO ZONES AND A SECOND PASSAGEWAY INTERCONNECTING INTERMEDIATE PORTIONS OF THE CONTACTING ZONES; THE IMPROVEMENT IN THE METHOD OF CONTROLLING THE FLOW OF SUCH SOLIDS BETWEEN SAID ZONES WHICH COMPRISES PASSING A STREAM OF GAS UPWARDLY THROUGH THE FIRST OF SAID CONTACTING ZONES AT A VELOCITY ADJUSTED TO MAINTAIN A LAYER OF FLUIDIZED SOLIDS IN THE LOWER SECTION OF SAID ZONE, PASSING A STREAM OF GAS UPWARDLY THROUGH THE SECOND CONTACTING ZONE AT A VELOCITY RELATIVELY LOWER THAN THE VELOCITY OF THE GAS PASSING THROUGH THE FIRST CONTACTING ZONE TO MAINTAIN A LAYER OF FLUIDIZED SOLIDS MORE DENSE THAN THAT MAINTAINED IN THE FIRST CONTACTING ZONE, KEEPING SUFFICIENT FINELY DIVIDED MATERIAL IN BOTH OF SAID CONTACTING ZONES TO MAINTAIN THE UPPER LEVEL OF SAID LAYERS ABOVE THE INTERMEDIATE COMMUNICATING PASSAGEWAY, MAINTAINING THE LEVEL OF THE LAYER OF FLUIDIZED SOLIDS IN THE FIRST CONTACTING ZONE AT A SUFFICIENT DISTANCE ABOVE THE INLET TO THE PASSAGEWAY INTERCONNECTING INTERMEDIATE PORTIONS OF THE CONTACTING ZONES TO DEVELOP A PSEUDO-HYDROSTATIC PRESSURE AT SAID INLET WHICH IS GREATER THAN THE PSEUDO-HYDROSTATIC PRESSURE EXISTING AT THE OUTER END OF SAID PASSAGEWAY DEVELOPED BY THE LEVEL OF THE MORE DENSE LAYER OF FLUIDIZED SOLIDS IN SAID SECOND CONTACTING ZONE ABOVE SAID OUTLET AND THEREBY CAUSING A STREAM OF FINELY DIVIDED SOLIDS TO FLOW FROM THE LESS DENSE LAYER IN SAID FIRST CONTACTING ZONE THROUGH SAID INTERMEDIATE COMMUNICATING PASSAGEWAY INTO THE MORE DENSE LAYER IN SAID SECOND CONTACTING ZONE, MAINTAINING THE TOP LEVEL OF THE LAYER OF FLUIDIZED SOLIDS IN SAID SECOND CONTACTING ZONE A SUFFICIENT HEIGHT ABOVE THE INLET TO THE PASSAGEWAY CONNECTING THE BOTTOM PORTIONS OF THE TWO ZONES TO DEVELOP A PSEUDO-HYDROSTATIC PRESSURE AT THE LAST NAMED INLET WHICH IS GREATER THAN THE PSEUDO-HYDROSTATIC PRESSURE EXISTING AT THE OUTLET END OF THE PASSAGEWAY CONNECTING THE BOTTOM PORTIONS OF THE TWO ZONES DEVELOPED BY THE LEVEL OF SAID LESS DENSE LAYER OF FLUIDIZED SOLIDS IN SAID FIRST CONTACTING ZONE ABOVE THE LAST MENTIONED OUTLET THEREBY CAUSING A STREAM OF FINELY DIVIDED SOLIDS TO FLOW FROM SAID MORE DENSE LAYER IN SAID SECOND CONTACTING ZONE THROUGH THE PASSAGEWAY CONNECTING THE BOTTOM PORTION OF THE TWO ZONES INTO THE LESS DENSE LAYER IN SAID FIRST CONTACTING ZONE.