PROCEDIMENTO DI CRACKING CATALITICO DI IDROCARBURI CON RIGENERAZIONE DEL CATALIZZATORE IMPIEGATO

摘要

1500357 Catalyst regeneration in cracking processes STANDARD OIL CO 14 March 1975 [14 March 1974] 10702/75 Heading CSE [Also in Division B1] A hydrocarbon catalytic cracking process includes the stages of hydrocarbon cracking and catalyst regeneration, the catalyst regeneration stage comprising (a) regenerating fluidized hydrocarbon catalyst particles deactivated by coke deposits by contact with an oxygen-containing gas in a regenerator to combust the coke and produce a CO containing flue gas; (b) passing the flue gas from the regenerator; (c) oxidizing the flue gas to combust CO and form a combusted effluent of reduced CO content; (d) withdrawing catalyst from the regenerator; (e) passing withdrawn catalyst, which is free of coke, in heat exchange relation with the effluent to transfer heat from the effluent to the catalyst; (f) conveying the heated catalyst to a position within the catalytic cracking process. The CO combustion may be catalysed with Fe, Ni, V, Co or rare earth or oxides or salts of these metals, which may be in the form of particles, linings, screens, or grids and may be mechanically supported. Suitable cracking catalysts are SiO 2 and/or Al 2 O 3 , or MgO or Zn. Particularly useful are SiO 2 /Al 2 O 3 mixtures containing 10-50 wt. per cent Al 2 O 3 optionally mixed with molecular sieves, or clay extended Al 2 O 3 . Suitable molecular sieves are listed. The catalyst may be fed to heat exchange from (a) the cracking catalyst regenerator; (b) a cooler after the regenerator or (c) a stripper of the regenerator, and in addition fresh catalyst may be supplied. The catalyst may be heat transferred directly either by (a) mixing catalyst and flue gas then igniting preferably using combustion promoters or (b) adding catalyst after combustion in the combustor or flue gas line. There may be more than one combustor per regenerator or vice versa. Alternatively the catalyst may be heat transferred indirectly by (a) heat exchange fluids or (b) passing catalyst in a tube concentrically arranged in a pipe containing flue gas. The heated catalyst may be used by returning it to the cracking reactor or to one or more endothermic or exothermic cracking zones, or to preheat oil for fractionation, or may be mixed with unregenerated coked catalyst or used to heat the regenerator.