Recycling of Low-Value Hydrocarbon Cuts by Means of Multiple Injections to FCC Units

I. TISCORNIA; G. DE LA PUENTE; U. SEDRAN

INDUSTRIAL & ENGINEERING CHEMICAL RESEARCH

AMER CHEMICAL SOC

Lugar: Washington; Año: 2002 vol. 41 p. 5976 - 5982

0888-5885

The upgrading of a visbreaker naphtha by recycling it into an FCC unit was studied followingthe approach of multiple injections (with the naphtha in the first one) using a laboratory risersimulator reactor and an equilibrated catalyst. The experimental work comprised three differentstages: a study of the crackability of the naphtha under conventional FCC conditions (500-550°C, CATOIL 6.1, short contact times), a study of the conversion of the naphtha under a regimeof high severity (CATOIL 37), and a study of the impact of this injection on the overall FCCoperation. Heavy C7-C9 olefins and n-paraffins are converted, and aromatics and C4-C6i-paraffins are the most noticeable products. Even though the RON in the gasoline cut of theproducts does not change, modifications in the composition are advantageous because heavyolefins and n-paraffins are selectively converted. The high-severity regime induces more profoundchanges in the composition of the gasoline cut that significantly improve the blending properties.More importantly, the first injection would not interfere with the standard feedstock injection,because catalyst properties and performance are not altered, as shown by experiments withcoked and regenerated catalyst.