Enhancement of Residue Hydroprocessing Catalysts by Doping with Alkali Metals

Abstract

Alkali metal nitrates and hydroxides were added to Ni/Mo on γ-alumina hydroprocessing catalysts in order to neutralize surface acidity, thereby reducing coke deposition on the catalyst and enhancing activity. The initial activity of the catalysts was tested by hydroprocessing Athabasca bitumen in microbatch reactors and a 1 L continuous-feed stirred reactor. Addition of nitrate salts was not effective. Addition of 0.26 mmol alkali metal hydroxide/g of catalyst was sufficient to reduce the concentration of very acidic sites in the catalyst, as measured by thermal desorption of pyridine. At this level of addition, coke deposition was reduced and hydrodesulfurization was increased. Experiments in a batch reactor showed that Li and Na were similar in activity, giving 80% sulfur removal compared to 63% with the untreated commercial catalyst. Coke content was reduced, with carbon concentration decreasing from 17.3% in the untreated catalyst to 14.4% with Li or Na at 26 to 28 mmol/g. The Na-doped catalyst gave a 40% increase in the hydrodesulfurization rate constant over the untreated catalyst in a continuous-feed stirred reactor during a 6 h experiment, consistent with the batch results. Asphaltene removal was also improved, while hydrodenitrogenation, microcarbon residue conversion, and residue conversion were unaffected.

Characterization and evaluation of Ni/SiO2 catalysts for hydrogen production and tar reduction from catalytic steam pyrolysis-reforming of refuse derived fuel

“…Ce to the sol-gel catalyst, due to the enhancement of the catalytic activity by promoting cracking reactions, as reported previously during the partial oxidation of methane [53,54].…”

Fate of Organic Liquid-Crystal Domains during Steam-Assisted Gravity Drainage/Cyclic Steam Stimulation Production of Heavy Oils and Bitumen

“…The cell design and heating system used in this study are identical to those used previously for a laboratory-scale hydroprocessing study . The batch micro cells have an internal volume of ∼15 mL and are constructed from Swagelok parts.…”

“…The cell design and heating system used in this study are identical to those used previously for a laboratory-scale hydroprocessing study. 25 The batch micro cells have an internal volume of ∼15 mL and are constructed from Swagelok parts. These cells have an upper operating range of 873 K and 15 MPa, limits well in excess of the conditions explored here.…”

Hydrotreating Chemistry of Model Products from Bioprocessing of Carbazoles

“…Many of the compounds of interest were relatively insoluble in suitable solvents at room temperature, therefore, trials were carried out in 15 mL batch reactors constructed from stainless steel and Swagelok tube fittings as described by Richardson and Gray . All reactions were conducted for 20 min in the microreactor, which was heated with a fluidized sandbath at various set temperatures.…”