CHEMICAL TRANSFORMATIONS OF NITROGEN COMPOUNDS DURING CATALYTIC CRACKING AND THEIR IMPACT ON CATALYST DEACTIVATION

This study is devoted to the investigation of the behavior of nitrogen-containing compounds in heavy petroleum fractions, namely SL-CGO (slurry coke gas oil) and SL-VR (slurry vacuum residue), under fluid catalytic cracking (FCC) conditions. The feedstocks contain 0.61 and 0.79 wt% nitrogen, respectively, along with high Conradson carbon residues, indicating their problematic nature for catalytic processing. The structural characteristics and distribution of nitrogen species were analyzed using electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry (ESI FT-ICR MS).Cracking experiments carried out over different media, including quartz sand, kaolin matrix, HY-type zeolite, and a laboratory-prepared zeolite–matrix catalyst, demonstrated that both feedstock conversion and the fate of nitrogen compounds strongly depend on the nature of the catalytic environment. The analyses revealed the predominance of single-nitrogen species among nitrogen classes and showed that the catalyst selectively influences their distribution. In addition, the size and molecular architecture of nitrogen compounds govern their interaction with active sites.Overall, the results provide insight into the key structural factors controlling catalyst stability during FCC processing of nitrogen-rich heavy feeds and offer a scientific basis for process optimization. Keywords: catalytic cracking, nitrogen-containing organic compounds, catalyst deactivation, heavy oil fractions, structural and compositional changes.