Air feed system

Claim 1

IN A CATALYST CRACKING UNIT INCLUDING A REACTOR WITH AN INLET ADAPTED TO RECEIVE GAS OIL TO BE CRACKED IN THE PRESENCE OF A CATALYST, AND A REGENERATOR WITH AN INLET CONNECTION FROM THE REACTOR FOR RECEIVING SPENT CATALYST, AN EXHAUST OUTLET AND AN OUTLET CONNECTION TO THE REACTOR FOR PROVIDING CATALYST THERETO, AN AIR FEED SYSTEM COMPRISING: (A) A BLOWER HAVING AN INLET ADAPTED TO RECEIVE AIR, AND AN OUTLET CONNECTED TO THE REGENERATOR FOR PROVIDING AIR FOR COMBUSTION AND TO THE REGENERATOR INLET FOR PROVIDING AIR FOR CARRYING SPENT CATALYST; (B) MEANS CONNECTED TO THE BLOWER FOR CONTROLLING AIR FLOW; (C) MEANS CONNECTED TO THE REACTOR INLET AND TO THE BLOWER INLET FOR SENSING GAS OIL FLOW AND AIR FLOW, AND FOR PROVIDING SIGNALS REPRESENTING EACH OF SUCH FLOWS; (D) AN AUTOMATIC CONTROLLER CONNECTED TO THE SENSING MEANS AND TO THE FLOW CONTROL MEANS FOR CONTROLLING AIR FLOW IN ACCORDANCE WITH SIGNALS FROM THE SENSING MEANS; (E) MEANS CONNECTED TO THE REGENERATOR EXHAUST OUTLET FOR ANALYZING THE OXYGEN CONTENT OF REGENERATOR EXHAUST, AND FOR PROVIDING SIGNALS REPRESENTING SUCH OXYGEN CONTENT; AND (F) MEANS CONNECTED TO THE CONTROLLER AND TO THE ANALYZING MEANS FOR OVERRIDING THE CONTROLLER RESPONSE TO SIGNALS REPRESENTING GAS OIL FLOW AND AIR FLOW TO CONTROL AIR FLOW IN ACCORDANCE WITH REGENERATOR EXHAUST OXYGEN CONTENT.