Fluid cracking process and apparatus for maximizing light olefins or middle distillates and light olefins

摘要

A fluid catalytic cracking apparatus and process is disclosed, providing for efficient conversion of heavy hydrocarbon feeds to light olefins, aromatics, and gasoline. A countercurrent flow reactor operating in bubbling or turbulent fluidization regimes is integrated with a fluid catalytic cracking riser reactor. A heavy hydrocarbon feed is catalytically cracked to naphtha and light olefins in the riser reactor, a co-current flow reactor. To enhance the yields and selectivity to light olefins, cracked hydrocarbon products from the riser reactor, such as C4 and naphtha range hydrocarbons, may be recycled and processed in the countercurrent flow reactor. The integration of the countercurrent flow reactor with a conventional FCC riser reactor and catalyst regeneration system may overcome heat balance issues commonly associated with two-stage cracking processes, may substantially increase the overall conversion and light olefins yield, and/or may increases the capability to process heavier feedstocks.

主权项

1. A process for the catalytic cracking of hydrocarbons, comprising:
regenerating a spent catalyst comprising a first cracking catalyst having a first average particle size and density and a second cracking catalyst having a second average particle size and density in a catalyst regeneration vessel to form a regenerated catalyst comprising the first cracking catalyst and the second cracking catalyst, wherein the average particle size of the first cracking catalyst is less than the average particle size of the second cracking catalyst; contacting in co-current flow a first hydrocarbon feed with a first portion of the regenerated catalyst in a riser reactor to produce a first effluent comprising a first cracked hydrocarbon product and a spent mixed catalyst fraction; feeding a second portion of the regenerated catalyst to a second cracking reactor; concurrently in the second cracking reactor:
separating the first cracking catalyst from the second cracking catalyst based on at least one of density and particle size;contacting in countercurrent flow a second hydrocarbon feed with the second cracking catalyst to produce a second cracked hydrocarbon product; recovering a second effluent from the second cracking reactor comprising the second cracked hydrocarbon product and the first cracking catalyst as an effluent from the upper portion of the second cracking reactor and recovering a third effluent comprising spent second catalyst from the bottom of the second cracking reactor feeding the first effluent and the second effluent to a disengagement vessel to separate the spent mixed catalyst fraction and the separated first cracking catalyst from the first and second cracked hydrocarbon products; feeding the separated catalysts from the disengagement vessel to the catalyst regeneration vessel as the spent catalyst.