FCC Operation with Split Feed Injections

G. DE LA PUENTE; G. CHIOVETTA; U. SEDRAN

INDUSTRIAL & ENGINEERING CHEMICAL RESEARCH

AMER CHEMICAL SOC

Lugar: Washington; Año: 1999 vol. 38 p. 368 - 372

0888-5885

A laboratory Riser Simulator unit was used to study the conversion of n-hexadecane on anequilibrium FCC catalyst, which was injected split into two fractions with different volume ratios(Rv, from 1:1 to 3:1) and times for the second injection (t1, 2-6 s), and the same total contacttime of 12 s at 500 and 550 °C. Results were compared with reference experiments with singleinjections. It was observed that the conversions and gasoline yields under the split injectionswere equal or lower than the standard ones at both temperatures, that the yields of differenthydrocarbon groups were unaltered, and that coke yields were always lower. Significant changeswere observed in product light olefins C4-C6: at the same conversion, the split injectionsincreased their selectivities, improvements being more important at lower temperature andhigher Rv, while the influence of t1 was less important. Heavier olefins showed the highestsensitivity to these changes. The shifts were justified with basis on the partial catalystdeactivation imposed by the coke formed during the first step that would interfere moreimportantly with hydrogen transfer reactions in the second step, thus helping to preserve olefins