Patent ID: 8314280
Filing Date: 2012-11-20
Classification: C07C,Y02P

Abstract:
1. A process for the production of light olefins, comprising: feeding a hydrocarbon stream comprising C4 to C6 olefins to a cracking reaction zone comprising at least four reactors operated in a staggered reaction/regeneration cycle; contacting at least a portion of the C4 to C6 olefins with a catalyst in one or more of the reactors of the cracking reaction zone operating in a reaction cycle to crack at least a portion of the C4 to C6 olefins to form C2 to C3 olefins; recovering an effluent from the cracking reaction zone comprising the C2 to C3 olefins and unreacted C4 to C6 olefins; separating the effluent from the cracking reaction zone into at least two fractions including one or more fractions comprising at least one of C2 hydrocarbons, C3 hydrocarbons, and a combination thereof, and one or more fractions comprising at least one of C4 hydrocarbons, C5 hydrocarbons, C6 hydrocarbons, and a combination thereof; contacting the hydrocarbon stream with a regeneration gas in indirect heat exchange to increase a temperature of the hydrocarbon stream prior to the contacting at least a portion of the C4 to C6 olefins with a catalyst in reactors of the cracking reaction zone in a reaction cycle; feeding the regeneration gas and at least one of oxygen and air to one or more of the reactors in the cracking reaction zone operating in a regeneration cycle to regenerate the catalyst contained therein; recovering a regeneration gas effluent comprising combustion products from the reactors in the cracking reaction zone in a regeneration cycle; withdrawing at least a portion of the recovered regeneration gas effluent comprising combustion products as a purge; combining at least a portion of the regeneration gas effluent with make-up nitrogen to form a mixed regeneration gas; heating the compressed mixed regeneration gas to a temperature in the range from about 600° C. to about 1000° C.; and feeding the heated mixed regeneration gas to the cracking reaction zone as the regeneration gas.