Novel lab-scale deactivation method for FCC catalyst: inducing realistic accessibility responses to iron poisoning

Life and death of a single catalytic cracking particle

“…In addition to pore size distribution, we also measured the change in mass transfer rates, or accessibility, supposedly caused by metals blocking pores. For that purpose, an in-house developed accessibility test [Albemarle accessibility index (AAI)] was used to measure the liquid-phase diffusion of large asphaltene molecules into the catalyst ( 9 ). In this test, no chemical reaction is occurring; it only determines the diffusion characteristics of the specific catalyst samples.…”

“…Ni and V contaminants are predominantly present in conventional heavy crude oils, whereas Fe contaminants are known to be present at relative high concentrations in tight and/or shale oils. Metal accumulation occurs via deposition and incorporation into the catalyst body and can cause unwanted shifts in product distribution, destabilize zeolite domains ( 6 – 8 ), and reduce bulk accessibility ( 9 , 10 ). We summarize these effects as “catalyst aging.” Demetallization methods to mitigate metal deposition have been proposed ( 11 ); however, to successfully commercialize such techniques, it is crucial to understand metal behavior throughout the FCC particles.…”

Vanadium effect on HUSY zeolite deactivation during hydrothermal treatment and cyclohexane model reaction

“…The most common metals, which are present in the FCC feedstocks are vanadium [2], nickel [3,4] and iron [5,6]. These metals act as poisons to acid sites of the zeolite and present dehydrogenative characteristics.…”

“…When iron is concerned, the morphology of the FCC catalyst particles could be modified. This phenomenon is often referred to as ''nodulation'' and occurs after a critical iron content; the accessibility of the particles can be severely reduced [6].…”

Performance of mesoporous silica-doped aluminas on nickel passivation

“…During the heavy crude refining process, the high content of organometallic compounds contaminates the catalyst by destroying the zeolite framework or acting as a competitive catalyst [1][2][3]. Therefore, modern cracking catalysts are required to deliver excellent selectivity in the presence of contaminant metals [4].…”