Effect of Diluents in Controlling Sediment Formation During Catalytic Hydrocracking of Kuwait Vacuum Residue

Investigation on sediment formation in residue thermal conversion based processes

“…The correlation coefficients of density and fraction of aromatic carbon of VROs and the slope after induction period are r = −0.64 and r = −0.54 respectively. These findings are in line with the results reported by Marafi [33] and Marques [34] who showed that during hydrocracking of Kuwait and Ural VRO sediments in unconverted residual oil were reduced when high aromatic FCC HCO (heavy cycle oil) was added to the VRO feed. Having in mind that both residue hydrocracking and thermal cracking are thermal conversion based processes one can expect that the addition of FCC slurry oil to a VRO will diminish sedimentation.…”

“…They include the use of specially designed additives and low sediment catalysts [21,22,31,32]. Marafi et al [33] and Marques et al [34] reported that the addition of high aromatic fluid catalytic cracking heavy gas oil reduced significantly sediment content in the unconverted product. Yang et al [35] and Liu et al [36] reported that toluene insolubles in thermal cracking and coke yield in residue catalytic hydroprocessing correlated with the residue feed aromaticity.…”

“…However the sedimentation still restricts further increase of conversion even in the ebullated bed catalytic hydrocracking. Different approaches have been used to increase the achievable maximum conversion in both visbreaking and ebullated bed catalytic hydrocracking [21,22,[30][31][32][33][34]. They include the use of specially designed additives and low sediment catalysts [21,22,31,32].…”

Investigation of the mechanism of sediment formation in residual oil hydrocracking process through characterization of sediment deposits

“…In our previous studies [13,14] attention was paid to understand the role of asphaltenes and operating severity in sediment formation. The effect of adding aromatic rich gas oils as diluents to vacuum residue (VR) feed on various conversions as well as on sediment formation was reported by us in a recent paper [15].…”

“…The feedstock characteristics and operating procedures were reported in detail elsewhere [15]. The feedstock contained 5.2 wt.% S, 0.44 wt.% N, 113 ppm V, 30 ppm Ni, 7.5 wt.% asphaltenes, and 18.5 wt.% CCR.…”