Comments on the HDS, HDM and HDN activities of commercial catalysts in the hydrotreating of heavy crude oils

Influence of oxygen-, nitrogen-, and sulfur-containing compounds on the hydrodeoxygenation of phenols over sulfided cobalt-molybdenum/.gamma.-alumina and nickel-molybdenum/.gamma.-alumina catalysts

“…As biomass-derived oils do not contain sulfur compounds, a partial pressure of hydrogen sulfide is likely to be required for preserving the sulfided catalysts from oxidation by oxygenated compounds (Yoshimura et al, 1991) or reduction of the sulfided phase by hydrogen (Gajardo et al, 1982), according to operating conditions.…”

“…Depending on the origin of the pyrolyzed biomass, up to 3.3 wt % nitrogen compounds were found in bio-oils (Churin et al, 1988), although normal values are around 0.1 % wt (Bridgwater and Bridge, 1991). In order to stay active for long periods, sulfided catalysts may require a hydrogen sulfide partial pressure (Yoshimura et al, 1991;Sapre and Gates, 1982; Gajardo et al, 1982). Since the sulfur content of bio-oils is generally very low, sulfur compounds have to be added.…”

Aqueous Interfacial Chemistry in the Catalyst Preparation of NiMo/Al2O3 System by EDTA-Containing Impregnation

“…Among others, the use of organic chelating agents in the impregnating solution, for instance, nitrilotriacetic acid (NTA), helps yield the catalytically active CoMoS phase. [6][7][8][9][10][11] Industrial HDS catalysts are mainly prepared by the incipient wetness impregnation method, [12][13] which consists of several sequential synthesis steps starting from an aqueous solution of active component precursors and including impregnating a porous support, drying, calcination, and sulfidation. Ammonium heptamolybdate (AHM), cobalt, or nickel nitrates are commonly used as active-phase precursors in aqueous solution.…”

Effect of catalyst properties and operating conditions on hydroprocessing of high-metals feeds.

“…Tamm et al (1981) proposed that the initial deactivation could be caused by the partial surface poisoning by the feed metals. The fact that most of the coke is deposited during the first 24 h of operation, while the initial deactivation lasts longer, may support this theory (Pazos et al, 1981; Gajardo et al, 1982).…”