Production of hydrogen cyanide

Claim 1

A PROCESS FOR PRODUCTION OF HYDROGEN CYANIDE WHICH COMPRISES (1) SUSPENDING FINELY DIVIDED INERT SOLIDS IN A REACTANT GAS STREAM COMPRISING A NON-AROMATIC HYDROCARBON HAVING AN ATMOSPHERIC BOILING POINT BELOW ABOUT 600* F., OXYGEN AND AMMONIA; (2) PASSING THE REACTANT GAS CONTAINING SUSPENDED SOLIDS THROUGH A PREHEATING ZONE WHEREIN IT IS HEATED TO A TEMPERATURE BETWEEN ABOUT 600* C. AND ABOUT 1500* C. SUBSTANTIALLY SOLELY BY INDIRECT HEAT EXCHANGE WITH HOT PRODUCT GAS AND SAID SOLIDS; (3) PASSING THE PREHEATED REACTANT GAS AND SOLIDS INTO A CONFINED FREE SPACE REACTION ZONE WHEREIN REACTION OCCURS WITH THE FORMATION OF A HOT HYDROGEN CYANIDECONTAINING PRODUCT GAS, SAID REACTION ZONE HAVING A CROSSSECTIONAL AREA SUBSTANTIALLY LARGER THAN SAID PREHEATING ZONE; (4) MAINTAINING THE RESIDENCE TIME OF THE REACTING GAS WITHIN THE REACTION ZONE BETWEEN ABOUT 0.01 AND ABOUT 0.2 SECOND; (5) PASSING SAID PRODUCT GAS TOGETHER WITH THE SEPARATED SOLIDS THROUGH A COOLING ZONE IN INDIRECT HEAT EXCHANGE RELATIONSHIP WITH SAID PREHEATING ZONE, WHEREBY SAID PRODUCT GAS AND SOLIDS ARE COOLED BY TRANSFER OF HEAT TO THE REACTANT GAS CONTAINING SUSPENDED SOLIDS PASSING THROUGH SAID PREHEATING ZONE; (6) SEPARATING THE COOLED PRODUCT GAS FROM SAID SOLIDS AND (7) RETURNING THE SEPARATED SOLIDS WITHOUT THE ADDITION OF HEAT THERETO TO STEP (1) FOR RE-SUSPENSION IN THE REACTANT GAS STREAM.