Fluidized catalytic cracking process

Abstract

A sequential processing for heavy petroleum residues is disclosed which uses a separate mixture of catalyst and adsorbent. The solid adsorbent and FCC (fluids catalytic cracking) catalyst particles differ significant at least on particle size or density or both. The adsorbent preferably consist of calcined coke or metal oxides of Al, Si, or Mg having enhanced ability of selectively capture different impurities of the residual oil. The adsorbent particles first treat the residual hydrocarbons in the riser bottom end subsequently the actual catalyst tales care of catalytic cracking in the upper section of the riser. The spent solid mixture is fed to the catalyst separator which uses steam at sufficiently high velocity but at lower temperature to lift the catalyst particles out of the separator. Such a novel low temperature faster separation minimizes Vanadium mobility and deactivation of the catalyst. A net coke stream is withdrawn from the separator/burner especially while processing residues above 5 wt % CCR. This allows successful processing of even very heavy residues with CCR of 20 wt % and metals (vanadium & nickel) or 300 ppm, without requiring higher catalyst make up or catalyst and edsorbent cooling.