Fluidized catalytic cracking process

A fluidized catalytic cracking process for converting a feedstock comprising impurities and heavy vacuum gas oil and residual oil fractions into lighter products, the process comprising, in the order recited:

• contacting said feedstock with an adsorbent in a bottom portion of a riser so that at least the impurities are adsorbed by the adsorbent
• wherein the adsorbent has a particle size ranging from 200 to 500 micrometers, and wherein the adsorbent has a particle density ranging from 1500 to 3000 kg/m3);
• contacting the feedstock and the adsorbent with a catalyst
• wherein the particles of catalyst have a particle size ranging from 20 to 200 micrometers and a particle density ranging from 1200 to 1800 kg/m3,
• under fluidized catalytic cracking conditions, to produce a product mixture comprising product hydrocarbons, adsorbent and spent catalyst;
• separating a mixture of the spent catalyst and the adsorbent from the product hydrocarbons in a stripper;
• introducing the mixture of the spent catalyst and the adsorbent into a separator, and separating the spent catalyst from the adsorbent in the presence of steam and at a temperature ranging from 450 to 600° C. to provide spent adsorbent;
• introducing the spent adsorbent from the separator into a burner and firing the spent adsorbent under conditions effective to activate the adsorbent and provide activated adsorbent;
• introducing the spent catalyst from the separator into a regenerator to provide activated catalyst;
• and
• recycling the activated adsorbent and the activated catalyst into the riser.