Nickel-tolerant zeolite/boron catalysts: Comparing the performances in cracking of light and heavy hydrocarbon model feedstocks

The deactivation of zeolite catalysts by nickel deposition during catalytic cracking of nickel-contaminated feedstocks is a significant issue, especially in Residue Fluid Catalytic Cracking (RFCC) processes. This study explores the efficacy of boron modification in mitigating nickel-induced deactivation across three zeolite types (Y-5.1, USY-5.2 and VUSY-12) with variable silica-to-alumina ratios. Nickel was introduced at 30 wt% concentration, while boron loadings ranged from 1 to 10 wt%. The boron-modified zeolites showed a recovery in crystallinity, with increases from 43 % to 93 % at 10 wt% boron. Pyridine-FTIR demonstrated that the introduction of boron enhanced the Bronsted acidity of the nickel-deactivated zeolites. Hydrogen Temperature Programmed Reduction (H 2 -TPR) showed a shift in NiO reduction temperatures from 450–500 °C to 600–700°C upon boron addition, indicating the formation of stronger acid sites. The catalytic performance tests showed that addition of boron effectively suppressed the formation of hydrogen and methane during the catalytic cracking of n-heptane and 1,3,5-triisopropylbenzene (TIPB), demonstrating its effectiveness in mitigating the adverse effects of nickel contamination. Boron modification led to a reduction in hydrogen yield by 30 % for Y-5.1, 56 % for USY-5.2, and 57 % for VUSY-12 during n-heptane cracking. For TIPB cracking, the corresponding reductions in hydrogen production were 22 %, 56 %, and 45 % for Y-5.1, USY-5.2 and VUSY-12, respectively. The level of the enhancement depends on zeolite types and silica-to-alumina ratios. These results suggest that boron enhances the structural stability of zeolite catalysts and mitigates the dehydrogenation effects of nickel, promoting improved performance in RFCC applications. • Residue Fluid Catalytic Cracking (RFCC) processes very heavy and dirty feedstocks. • Nickel deactivation of zeolites leads to dehydrogenation reaction during cracking. • Boron modification of nickel-deactivated zeolites leads to suppression of hydrogen. • Boron passivation of nickel-induced deactivation improves zeolites Bronsted acidity. • Boron passivation of nickel-deactivated zeolites leads to recovery of crystallinity.