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M-SBA-15 (M = Ti, Al, and Zr) materials with a Si/M ratio of 20 were synthesized using a direct synthesis method. M-SBA-15 supported NiMo hydrotreating catalysts with and without EDTA was prepared by an incipient wetness impregnation method. A EDTA/Ni molar ratio of 2 was used for catalysts with EDTA. The hydrotreating activities of these catalysts were measured using Athabasca bitumen derived heavy gas oil, and comparison was done with the performance of NiMo/SBA-15 and NiMo/γ-Al 2 O 3 catalysts. All catalysts were thoroughly characterized by BET, TPR, TPD, CO-chemisorption, XRD, XANES, HRTEM, ICP-MS, and 13 C NMR. Incorporation of Ti, Al, and Zr in SBA-15 framework results in an increase in the surface acidity and metal support interactions in otherwise neutral SBA-15 material. This increases the dispersion, and HDS, HDN and HDA activity of a NiMo/SBA-15 catalyst increases by 12%, 70%, and 22%, respectively, as in the case of a NiMo/Ti-SBA-15 (Cat-Ti) catalyst. EDTA addition helps in better redispersion of molybdenum during sulfidation/activation as indicated by HRTEM and CO chemisorption studies. A XANES Mo LIII-edge study for the oxide state of catalysts reveals that EDTA helps in the formation of a greater number of molybdenum in octahedral structures which are easily reducible during sulfidation as compared to molybdenum in tetrahedral structures. A power law based kinetic study indicates that addition of EDTA lowers the activation energy, which could be due to formation of a more favorable Type II NiMoS active site. The activity studies show that using EDTA increases the HDS, HDN, and HDA activity of a NiMo/M-SBA-15 catalyst by 18%, 36%, and 22%, respectively, as in the case of a NiMo/Ti-SBA-15/2EDTA (Cat-TiE) catalyst. Based on the results from different characterization techniques, the schematic is presented related to the effect of EDTA-Mo-support interactions on dispersion of active metals in catalysts. The results from characterization techniques are in parallel with catalytic activity which follows the order Cat-TiE > Cat-AlE > Cat-ZrE > Cat-Ti. However, the catalytic activity of Cat-TiE is almost comparable to that of a NiMo/γ-Al 2 O 3 catalyst and has the potential for superior hydrotreating catalyst.

In this study, we investigate the potential of co-processing hydrothermal liquefaction (HTL) biocrude with vacuum gas oil (VGO) in a hydrocracking process with hydrotreating as the first step. Experiments were conducted in a continuous hydroprocessing pilot plant in two stages: hydrotreating and hydrocracking. Two feeds were tested: first pure VGO to establish a baseline and then a co-processing blend having 7.5 vol % HTL biocrude. In the first stage, the VGO and co-processing blend were sequentially hydrotreated to meet the quality specification of the hydrocracking catalyst. The second stage consisted of hydrocracking the two hydrotreated products from the first stage, and the resulting products were distilled into naphtha, diesel, and jet fuel fractions for characterization. The hydrotreating step achieved satisfactory sulfur and nitrogen removal levels for both feeds, but it was ineffective in converting oxygen compounds in the co-processing blend, resulting in a product with 1530 ppmw oxygen. During hydrocracking, the co-processing blend required a higher reaction temperature than the baseline VGO to achieve the same conversion level, a behavior attributed to the oxygen and nitrogen levels in the co-processing blend after hydrotreating. Despite these effects, overall product distribution and hydrogen consumption for both scenarios were quite comparable. Characterization of hydrocracked products showed only subtle differences in quality and hydrocarbon type composition, while biogenic carbon measurements revealed that the majority of biogenic carbon is transferred to the naphtha, diesel, and jet fuel fractions.

Instead of powder, catalyst pellets are preferred in a fixed-bed reactor for Fischer–Tropsch synthesis (FTS). In this research, promoted iron catalysts supported on carbon nanotubes (CNT) were pelletized in two different shapes (spherical and cylindrical) using different bentonite loadings (10–20 wt %). The pellets were tested for mechanical strength using single pellet and bulk crushing test methods (ASTM D 4179, 6175, and 7084). The spherical pellets were found to sustain higher crushing strength as compared to cylindrical pellets. However, both spherical and cylindrical Fe/CNT pellets with 20 wt % bentonite loading were found to be mechanically stronger than commercial alumina spherical pellets, suggesting their suitability in fixed bed reactors. The pellets were characterized to determine the change in active metal dispersion and ease in reducibility based on their shape and binder content using CO chemisorption, XRD, and H2-TPR. The cylindrical shaped pelleted catalysts were found to be easy to reduce as compared to spherical shaped pelleted catalysts. All pellets were tested for FTS in a fixed bed reactor at 270 °C and 300 psi with syngas (H2/CO = 2.0) flowing at rate of 60 mL/min. The 20 wt % bentonite loaded Fe/CNT pellet was found to be stable with highest CO conversion and C5+ selectivity among all pelleted catalysts. The decline in CO conversion in pelleted Fe/CNT catalyst containing 10–15 wt % bentonite loading could be due to the structural instability of these materials during reaction. The internal mass transfer calculations estimated severe diffusional limitations in spherical pellet catalysts resulting in sharp decline in their FTS activity. Hence, cylindrical pelleted catalyst containing 20 wt % bentonite was found to be best performing among the series and its performance for FTS was optimized for temperature, pressure, and GSHV using the Taguchi method.

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