Sažetak
Današnje sirovine za proces fluid katalitičkog krekiranja sadrže velike količine ostataka atmosferske i vakuum destilacije koje su bogate sumporom. Produkti nastali katalitičkim krekiranjem, prvenstveno FCC benzin i lako cikličko ulje, predstavljaju glavne izvore sumpora u motornom benzinu, odnosno dizelskom gorivu. FCC benzin sudjeluje s 35-40 vol %. u motornom benzinu, a pri tom daje 98 % od ukupnog sumpora prisutnog u motornim benzinima. Ove dvije činjenice ukazuju na važnost istraživanja raspodjele sumpora u FCC benzinu i drugim produktima katalitičkog krekiranja dobivenih iz različitih sirovina.
U radu su uspoređeni prinosi produkata katalitičkog krekiranja plinskih ulja dobivenih iz sirovina koje su sadržavale različite količine sumpora. Ispitivanja su provedena na laboratorijskom uređaju za katalitičko krekiranje pomoću testa mikroaktivnosti (MAT). Dobiveni tekući produkti krekiranja frakcionirani su te je dobivenim frakcijama benzina, lakog cikličkog ulja i dekantiranog ulja određen sadržaj sumpora. Frakcijama benzina određen je istraživački oktanski broj (IOB) koji je koreliran sa sastavom i raspodjelom ugljikovodika u benzinu te sa sadržajem sumpora u sirovini, tj. u benzinu.
Dobiveni rezultati pokazuju da korištenjem hidroobrađene sirovine dolazi do povećanja konverzije i prinosa FCC benzina, smanjenja IOB FCC benzina i smanjenja sadržaja sumpora u svim tekućim produktima krekiranja.Abstract
The present feeds for the fluid catalytic cracking process contain large residual quantities of atmospheric and vacuum distillations that are rich in sulphur. The catalytic cracking products, primarily the FCC gasoline and light cyclic oil, represent the main sources of sulphur in motor gasoline and diesel fuel. The FCC gasoline share is 40 vol.% in motor gasoline, and it provides 98% of the total sulphur quantity contained in motor gasoline. These two facts emphasize the importance of testing sulphur distribution in FCC gasoline and in other products of catalytic cracking obtained from various feeds.
The paper compares the yields of gas oil catalytic cracking products obtained from the feeds containing different quantities of sulphur. Tests have been performed on the laboratory device for catalytic cracking by means of a microactivity test (MAT). The obtained liquid products of cracking are fractionated, so that the resulting fractions of gasoline, light cyclic oil and heavy cyclic oil have a determined sulphur content. The research octane number (RON) has been determined for gasoline fractions, and correlated with the content and distribution of hydrocarbons in gasoline, as well as with the content of sulphur in the feed i.e. gasoline.
The obtained results show that by using hydrotreated feed the conversion and yield of FCC gasoline have increased, while FCC gasoline RON has decreased, as well as the content of sulphur in gasoline and other liquid products of cracking
