INFLUENCE OF HYDROGEN SULFIDE AND OF AMMONIA ON THE HYDROCRACKING OF n-HEPTANE OVER A NiMo/Y ZEOLITE CATALYST

ABSTRACT n-Heptane hydrocracking was carried out at 380°C under a 6 MPa total pressure in the presence of hydrogen sulfide and of ammonia. The reaction occurs through a bifunctional process, cracking (C) following isomerization (I). H 2 S and NH 3 have a negative effect on the hydrocracking rate and increase the l/C ratio, which indicates a poisoning of the acid sites. The poisoning effect of NH 3 is due to its adsorption on the acid sites, whereas H 2 S favors the formation of light coke molecules.