Upgrading of heavy coker naphtha by means of catalytic cracking in refinery FCC unit

The upgrading of heavy coker naphtha under conditions of the industrial fluid catalytic cracking (FCC) unit has been investigated, with the aim of obtaining light olefins and a gasoline fraction suitable to be used in the blending of motor fuels. The experiments have been conducted in a riser simulator reactor at: 500 and 550 °C; catalyst to oil mass ratio, 6 gcat goil−1; and, contact time, 3 to 12 s. Moreover, the effect of the properties of two commercial equilibrium catalysts on the products has been also assessed. Products have been grouped in: dry gas, liquefied petroleum gases, gasoline, light cycle oil and coke. The presence of strong acid sites in the catalyst favors the formation of light olefins, yielding a 5 and 3.3 wt% of propylene and butenes, respectively, at 550 °C and 6 s. A higher content of zeolite (with moderate acid strength sites) and a bigger size of the mesopores of the matrix promote the formation of a commercially interesting gasoline fraction with a yield of 90 wt% under the same conditions, with a concentration of aromatics, naphthenes, n-paraffins, olefins and iso-paraffins of 25, 10, 28, 21 and 15 wt%, respectively, and a RON of 84. [Display omitted] •Catalytic cracking is assessed as an upgrading route for heavy coker naphtha•Commercial catalyst properties condition the distribution and composition of the products•A yield of propylene of 5 wt% and of butenes of 3.3 wt% with strong acid sites•Gasoline fraction yields a 90 wt% with moderate acid strength and mesoporous matrix•Gasoline (wt%): 25 aromatics; 10 naphthenes; 21 olefins; 28 n- and 15 iso-paraffins