Gasification of carbonaceous solids

Claim 1

IN THE PROCESS OF PRODUCING GAS MIXTURES CONTAINING CO AND H2 FROM SOLID CARBONACEOUS MATERIALS AND AN OXIDIZING GAS CONTAINING STEAM, WHEREIN THE OXIDIZING GAS IS CONTACTED IN A GASIFICATION ZONE AT GASIFICATION TEMPERATURES OF ABOUT 1600*-2000* F. WITH A DENSE, EBULLIENT, FLUIDIZED MASS OF FINELY DIVIDED CARBONACEOUS SOLIDS, AND THE HEAT REQUIRED BY SAID GASIFICATION PROCESS IS SUPPLIED BY COMBUSTION OF A PORTION OF SAID CARBONACEOUS SOLIDS AND DIRECT HEAT EXCHANGE OF BURNED SOLIDS AND SOLIDS UNDERGOING SAID GASIFICATION, THE IMPROVEMENT WHICH COMPRISES MAINTAINING AT LEAST TWO DENSE, EBULLIENT, FLUIDIZED BEDS OF FINELY DIVIDED FRESH CARBONACEOUS SOLIDS IN A PREHEATING ZONE, PASSING HOT GASES PRODUCED IN SAID GASIFICATION PROCESS BY THE OXIDATION OF CARBONACEOUS MATERIALS UPWARDLY THROUGH SAID BEDS IN SERIES, PASSING FINELY DIVIDED SOLIDS FROM BED TO BED COUNTERCURRENTLY TO SAID HOT GASES, HEATING THE SOLIDS IN A BED FIRST CONTACTED BY SAID HOT GASES TO A RELATIVELY HIGH TEMPERATURE OF ABOUT 500*-700* F. BUT BELOW THE LEVEL OF BEGINNING CARBONIZATION OF CARBONIZABLE SOLIDS IN HEAT EXCHANGE WITH SAID HOT GASES, AND THE SOLIDS IN A SUBSEQUENT BED IN HEAT EXCHANGE WITH GASES LEAVING SAID FIRST BED TO A RELATIVELY LOW TEMPERATURE BUT ABOVE THE DEW POINT OF SAID HOT GASES, FEEDING PREHEATED SOLIDS FROM SAID FIRST BED DIRECTLY TO SAID GASIFICATION ZONE, MAINTAINING THE CARBON CONCENTRATION IN SAID GASIFICATION RESIDUE OF ABOUT 30-70%, SUPPLYING GASIFICATION RESIDUE OF SAID CARBON CONCENTRATION SUBSTANTIALLY AT SAID GASIFICATION TEMPERATURE TO A COMBUSTION ZONE AND SUBJECTING IT TO COMBUSTION THEREIN, AND CONVERTING THE HEAT AVAILABLE IN SAID COMBUSTION ZONE INTO STEAM.