Fuel-blending stocks from the hydrotreatment of a distillate formed by direct coal liquefaction
- Sasol Technology Research and Development, Sasolburg (South Africa). Fischer-Tropsch Refinery Catalysis
The direct liquefaction of coal in the iron-catalyzed Suplex process was evaluated as a technology complementary to Fischer-Tropsch synthesis. A distinguishing feature of the Suplex process, from other direct liquefaction processes, is the use of a combination of light- and heavy-oil fractions as the slurrying solvent. This results in a product slate with a small residue fraction, a distillate/naphtha mass ratio of 6, and a 65.8 mass % yield of liquid fuel product on a dry, ash-free coal basis. The densities of the resulting naphtha (C{sub 5}-200{sup o}C) and distillate (200-400{sup o}C) fractions from the hydroprocessing of the straight-run Suplex distillate fraction were high (0.86 and 1.04 kg/L, respectively). The aromaticity of the distillate fraction was found to be typical of coal liquefaction liquids, at 60-65%, with a Ramsbottom carbon residue content of 0.38 mass %. Hydrotreatment of the distillate fraction under severe conditions (200{sup o}C, 20.3 MPa, and 0.41 g{sub feed} h{sup -1} g{sub catalyst}{sup -1}) with a NiMo/Al{sub 2}O{sub 3} catalyst gave a product with a phenol content of {lt}1 ppm, a nitrogen content {lt}200 ppm, and a sulfur content {lt}25 ppm. The temperature was found to be the main factor affecting diesel fraction selectivity when operating at conditions of WHSV = 0.41 g{sub feed} h{sup -1} g{sub catalyst}{sup -1} and PH{sub 2} = 20.3 MPa, with excessively high temperatures (T {gt} 420{sup o}C) leading to a decrease in diesel selectivity. The fuels produced by the hydroprocessing of the straight-run Suplex distillate fraction have properties that make them desirable as blending components, with the diesel fraction having a cetane number of 48 and a density of 0.90 kg/L. The gasoline fraction was found to have a research octane number (RON) of 66 and (N + 2A) value of 100, making it ideal as a feedstock for catalytic reforming and further blending with Fischer-Tropsch liquids. 44 refs., 9 figs., 12 tabs.
- OSTI ID:
- 20961444
- Journal Information:
- Energy and Fuels, Vol. 21, Issue 5; Other Information: andile.mzinyati@sasol.com; ISSN 0887-0624
- Country of Publication:
- United States
- Language:
- English
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