Method for production of cyclohexane by the hydrogenation of benzene

Claim 1

A PROCESS FOR THE PRODUCTION OF CYCLOHEXANE, WHICH PROCESS COMPRISES, IN COMBINATION, THE STEPS OF: (A) DIVIDING A FEED STREAM COMPRISING BENZENE INTO A PLURALITY OF SUBSTANTIALLY EQUAL INDIVIUAL PORTIONS; (B) COMBINING A FIRST SAID INDIVIDUAL PORTION OF SAID BENZENE FEED STREAM WITH AN EXCESS OF A GAS STREAM COMPRISING HYDROGEN AND WITH A FIRST STREAM OF A DILUENT COMPRISING CYCLOHEXANE HAVING A TEMPERATURE WITHIN THE RANGE OF FROM ABOUT 275 TO ABOUT 390* F., AND PASSING THE RESULTING MIXTURE INTO A FIRST HYDROGENATION ZONE OF A CORRESPONDING PLURALITY OF HYDROGENATION ZONES AT A INITIAL REACTION TEMPERATURE WITHIN THE RANGE OF FROM ABOUT 300 TO ABOUT 400*F.; (C) IN SAID FIRST HYDROGENATION ZNE, FORMING CYCLOHEXANE BY REACTING BENZENE AND HYDROGEN UNDER HYDROGENATION CONDITIONS IN THE PRESENCE OF A CATALYST CAPABLE OF CATALYZING THE HYDROGENATION OF BENZENE; (D) WITHDRAWING REACTION MIXTURE EFFLUENT AT AN ELEVATED FINAL REACTION TEMPERATURE NOT EXCEEDING ABOUT 600*F. FROM SAID FIRST HYDROGENATION ZONE; (E) COMBINING SAID EFFLUENT WITH ANOTHER INDIVIDUAL PORTION OF SAID BENZENE FEED STREAM AND WITH ANOTHER STREAM OF A DILUENT COMPRISING CYCLOHEXANE HAVING A TEMPERATURE WITHIN THE RANGE OF FRM ABOUT 50 TO ABOUT 150*F., AND PASSING THE RESULTING MIXTURE INTO A SUCCEEDING HYDROGENATION ZONE OF SAID PLURALITY OF HYDROGENATION ZONES AT AN INITIAL REACTION TEMPERATURE WITHIN THE RANGE OF FROM ABOUT 300 TO ABOUT 400*F.; (F) REPEATING SAID STEPS (C), (D), AND (E) FOR SAID SUCCEEDING HYDROGENATION ZONE AND ANY FURTHER SUCCEEDING HYDROGENATION ZONES WHICH SUCCEED SAID FIRST MENTIONED SUCCEEDING HYDROGENATION ZONE EXCEPT THE LAST HYDROGENATION ZONE IN SAID PLURALITY OF HYDROGENATION ZONES, WHEREBY SAID INDIVIDUAL PORTION OF SAID BENZENE FEED STREAM AND SAID INDIVIDUAL CYCLOHEXANE DILUENT STREAMS PASS THROUGH SAID INDIVIDUAL HYDROGENATION ZONES OF SAID PLURALITY OF HYDROGENATION ZONES IN PARALLEL AND SAID HYDROGEN PASSES THROUGH SAID PLURALITY OF HYDROGENATION ZONES IN SERIES; (G) WITHDRAWING HYDROGENATION ZONE EFFLUENT FROM SAID LAST HYDROGENATION ZONE OF SAID PLURALITY OF HYDROGENATION ZONES AT AN ELEVATED FINAL REACTION TEMPERATURE WITHIN THE RANGE OF FROM ABOUT 450 TO ABOUT 600*F.; (H) COOLING SAID LAST MENTIONED EFFLUENT TO A TEMPERATURE WITHIN THE RANGE OF FROM ABOUT 275 TO ABOUT 390*F. AND PASSING SAME TO A FIRST FLASH SEPARATION ZONE; (I) WITHDRAWING LIQUID PHASE FROM SAID FIRST FLASH SEPARATION ZONE AND PASSING A PORTION OF SAME TO SAID FIRST HYDROGENATION ZONE AS SAID FIRST STREAM OF CYCLOHEXANE DILUENT; (J) COOLING THE REMAINDER OF SAID LIQUID PHASE WITHDRAWN FROM SAID FIRST FLASH SEPARATION ZONE TO A TEMPERATURE WITHIN THE RANGE OF FROM ABOUT 50 TO ABOUT 150*F. AND PASSING SAME TO A SECOND FLASH SEPARATION ZONE; (K) WITHDRAWING LIQUID PHASE FROM SAID SECOND FLASH SEPARATION ZONE AND PASSING SEPARATE PORTIONS THEREOF TO SAID SUCCEEDING HYDROGENATION ZONES AS SAID CYCLOHEXANE DILUENT STREAMS USED THEREIN; (L) AND RECOVERING CYCLOHEXANE PRODUCT FROM THE REMAINDER OF SAID LIQUID PHASE WITHDRAWN FROM SAID SECOND FLASH SEPARATION ZONE.