FCC Study of Canadian Oil-Sands Derived Vacuum Gas Oils. 1. Feed and Catalyst Effects on Yield Structure

Abstract

This paper demonstrates the important roles of feedstock and catalyst in determining the yield structure during fluid catalytic cracking (FCC) of bitumen-derived vacuum gas oils (VGOs). Three nonconventional VGOs, derived from Canadian oil-sands bitumen, were catalytically cracked in a fluid-bed microactivity test (MAT) reactor. Two commercial equilibrium catalysts were used: a bottoms-cracking catalyst containing rare earth exchanged Y zeolite (REY), and an octane-barrel catalyst containing rare earth ultrastable Y zeolite (REUSY) mixed with a small amount of ZSM-5. Both catalysts were embedded in active matrixes. Results indicated that the REY catalyst was more active, producing higher yields of valuable distillates and less coke for the same feed, whereas the catalyst containing REUSY/ZSM-5 gave more light gases and less gasoline (although the quality of this gasoline might be better). These results could be related to catalyst properties including zeolite type, rare earth content, matrix pore structure, zeolite-to-matrix ratio, and surface characteristics. The three feeds were ranked based on their yield structures, which could be explained through feed analyses, precursor concentrations determined by GC-MS, and product characterization data from a PIONA analyzer. MAT results were compared with riser pilot plant data at 55 and 65 wt % conversion. In general, at the same conversion, the difference in a given product yield from the two units could be maintained within 15%. Coke yield showed a greater disagreement, however, due to methodological differences in the analysis.

Review on catalysis related research at CanmetENERGY

“…The REY catalyst gave better sulphur and nitrogen selectivities than the REUSY, which was attributed to the higher hydrogen transfer ability of the former. The MAT results were comparable to riser pilot plant data at 55 and 65 % conversions with reasonable agreement …”

“…To demonstrate the important role of feedstocks and catalysts in determining the FCC yield structure, 3 VGOs derived from Canadian oil sands bitumen were catalytically cracked in a fluid bed MAT unit with 2 commercial equilibrium catalysts, a rare earth exchanged Y zeolite (REY), and a rare earth ultra‐stable Y zeolite (REUSY) . The REY catalyst was more active, producing higher yields of valuable distillates and less coke with the same feed, whereas the REUSY catalyst gave more light gases and less gasoline.…”

Virgin Heavy Gas Oil from Oil Sands Bitumen as FCC Feed

“…In this study, regression lines were established for the data. Regression types were selected based on the best (highest) correlation factor, except in a few cases where the model was known (e.g., linear correlation for coke vs. CTO and exponential correlation for dry gas or coke vs. conversion) [10]. The trend lines based on the best correlation are provided only to indicate directional relationships.…”

“…A total of six runs per batch of ACE test per feed at catalyst/oil (C/O or CTO) ratios of 4, 6, 8, 10, and 11.25 (11.25 ran twice) g/g were conducted for each temperature. A feed of 100% bitumen HGO was not run due to poor FCC performance, as reported previously [4,10]. With a constant injection rate of 1.2 g/min, which gave an 8 h −1 weight hourly space velocity (WHSV), oil injection time was varied to obtain the desired CTO through the relationship WHSV = 60/[(C/O) × t], where t is the feed delivery time (feed injection time) in minutes and C and O are weights of catalyst and feed, respectively, in grams.…”

Characterization of Nitrogen and Sulfur Compounds in Hydrocracking Feedstocks by Fourier Transform Ion Cyclotron Mass Spectrometry

“…Moreover, supply of heavy and sour crude oil increases whereas the availability of light and sweet crude oils continues to decline [2,3] (Fig. 1, [4]).…”