Co-Processing of Jatropha-Derived Bio-Oil with Petroleum Distillates over Mesoporous CoMo and NiMo Sulfide Catalysts

Abstract

Abstract:The co-processing of an unconventional type of Jatropha bio-oil with petroleum distillates over mesoporous alumina-supported CoMo and NiMo sulfide catalysts (denoted CoMo/γ-Al 2 O 3 and NiMo/γ-Al 2 O 3 ) was studied. Either a stainless-steel high-pressure batch-type reactor or an up-flow fixed-bed reaction system was used under severe reaction conditions (330-350 • C and 5-7 MPa), similar to the conditions of the conventional diesel hydrodesulfurization (HDS) process. To understand the catalytic performance of the mesoporous sulfide catalysts for co-processing, we prepared two series of oil feedstocks. First, model diesel oils, consisting of hydrocarbons and model molecules with various heteroatoms (sulfur, oxygen, and nitrogen) were used for the study of the reaction mechanisms. Secondly, low-grade oil feedstocks, which were prepared by dissolving of an unconventional type of Jatropha bio-oil (ca. 10 wt %) in the petroleum distillates, were used to study the practical application of the catalysts. Surface characterization by gas sorption, spectroscopy, and electron microscopy indicated that the CoMo/γ-Al 2 O 3 sulfide catalyst, which has a larger number of acidic sites and coordinatively unsaturated sites (CUS) on the mesoporous alumina framework, was associated with small Co-incorporated MoS 2 -like slabs with high stacking numbers and many active sites at the edges and corners. In contrast, the NiMo/γ-Al 2 O 3 sulfide catalyst, which had a lower number of acidic sites and CUS on mesoporous alumina framework, was associated with large Ni-incorporated MoS 2 -like slabs with smaller stacking numbers, yielding more active sites at the brims and corresponding to high hydrogenation (HYD) activity. Concerning the catalytic performance, the mesoporous CoMo/γ-Al 2 O 3 sulfide catalyst with large CUS number was highly active for the conventional diesel HDS process; unfortunately, it was deactivated when oxygen-and nitrogen-containing model molecules or Jatropha bio-oil were present in the oil feedstock. In contrast, the mesoporous NiMo/γ-Al 2 O 3 sulfide catalyst, which had a high HYD activity and low affinity for heteroatoms, was efficient in the simultaneous removal of those heteroatoms from model diesel oils, and, in particular, Jatropha bio-oil co-fed with petroleum distillates. This could allow the production of a drop-in diesel-like fuel, which would be a greener fuel and reduce the CO 2 emissions and hazardous exhaust gases produced by the transport sector, reducing the burden on the environment.

Insight into the Microstructure and Deactivation Effects on Commercial NiMo/γ-Al2O3 Catalyst through Aberration-Corrected Scanning Transmission Electron Microscopy

“…This is inconsistent with the opinion reported by Topsøe et al [31], who used multiple spectral studies to illustrate the strong interactions between the monolayer and high-surface area alumina via Mo-O-Al linkages located at the edges, thus leading to low catalytic activity. From the above, the change trends of the size of MoS2 slabs and stacks for commercial NiMo/γ-Al2O3 catalyst using the Cs-STEM-HAADF mode are in analogy with previous works by TEM [13][14][15][16], while the observed difference is the variation of "fragment" structures once the catalyst was exposed to harsher reaction conditions from the mild one in this work, which may be partial resource for the larger slabs in Cat C and Cat D. In general, the distinction in overall microstructure variations for the four catalysts is presumably a reflection of the differences in catalytic activity of the NiMo/γ-Al2O3 catalyst. Note that a precise analysis of the identification of Ni by imaging in the active slabs is not possible in our case owing to complexity of γ-Al 2 O 3 .…”

“…Importantly, the smaller probe of Cs-STEM makes it possible to roundly delve the relationship of active phase with respect to their surface structures. Previous studies have shown that the size of the MoS 2 /WS 2 slabs and stacks in hydroprocessing catalysts would be changed under the reaction conditions by the TEM technique [13][14][15][16], and small size MoS 2 may have a better catalytic activity [17]. It is, therefore, still a striking work to exactly track the microstructure variations of NiMo/Al 2 O 3 catalyst during catalysis by the Cs-STEM-HAADF mode.…”

Developing Nickel–Zirconia Co-Precipitated Catalysts for Production of Green Diesel

“…The selective deoxygenation (SDO) of natural triglycerides over supported noble metals and conventional [Ni(Co)-Mo(W)]/Al 2 O 3 h.d.s. sulphided catalysts, obtained by hydrotreatment, have been extensively studied in recent years [12][13][14][15][16][17][18]. The SDO is realized by decarboxylation (removal of CO 2 ), decarbonylation (removal of H 2 O and CO) and/or hydrodeoxygenation (removal of H 2 O).…”

Hydrotreating of Jatropha-derived Bio-oil over Mesoporous Sulfide Catalysts to Produce Drop-in Transportation Fuels

“…The subsequent upgrading of bio-oil through hydrotreating technology using metal catalysts, such as Pd/C, or sulfide catalysts, such as Co-or Ni-promoted MoS 2 /γ-Al 2 O 3 , is required to remove the heteroatoms, resulting in clean and drop-in biofuel with composition and fuel property closed to petro-fuels [22]. Unfortunately, the heteroatoms, water, and unwanted impurities, which are originally present in bio-oil, poison the active sites of metal and sulfide catalysts, causing serious catalyst deactivation, and consequently, reducing the quality of hydrotreated bio-oil [23][24][25][26][27][28][29][30]. Yoshimura et al reported that the sulfide NiMo catalysts were deactivated by the oxygen-containing compounds due to the oxidation of active sites [23].…”

“…In the upgrading process, the upgrading catalysts, as aforementioned, were immediately deactivated by a high concentration of nitrogen-containing compounds when Jatropha bio-oil was directly used as a feedstock (Scheme 1a). To prevent catalyst deactivation, our previous study demonstrated a co-processing method for the upgrading of Jatropha bio-oil co-fed with petroleum distillates over sulfide CoMo and NiMo catalysts under severe conditions (330-350 • C and 5-7 MPa of H 2 ) [30]. The diesel-like fuel with nearly no heteroatoms (sulfur, oxygen, and nitrogen < 10 ppm) could be obtained by hydrotreating of oil feedstock containing ca.…”