HYDROPROCESSING OF PETROLEUM FRACTIONS OVER MODIFIED ALUMINIUM OXIDE CATALYSTS

The hydro processing of gasoline and diesel oil fractions over aluminum-nickel-molybdenum catalysts modified by additives HY, ZSM-5, phosphorus and rare earth elements were studied. At the hydro processing of straight-run gasoline over NiO-MoO3- Ce2О3-Р2О5–ZSM(30%)-Al2O3 the content of isoalkanes increases in comparison with the initial from 26.3 to 35.7- 38.3% at 320-400оС. The octane number of refined gasoline at 400оС is 83.7 (RON) and 69.7 (MON). The sulfur content decreases from 0.037% (initial gasoline) to 0.0022%. At hydro processing of straight-run gasoline over NiO-MoO3-La2О3-Р2О5-ZSM-Al2O3 in the range of 320–400 oC the content of isoalkanes is 30.7- 44.3%. The octane number of refined gasoline at 400oC is maximum and is equal to 91.8 (RON) and 72.4 (MON). Under these conditions the sulfur content decreases from 0.0092% to 0.0028%. The optimal conditions for the hydro processing of straight-run gasoline were revealed: T=400˚С, V=2 h-1, Р = 4.0MPa. The catalyst NiO-MoO3-La2О3-Р2О5-ZSM-HY-Al2O3 has the highest hydro desulfurizing activity, the residual sulfur content at 400oС is 0.0012%. The catalyst NiO-MoO3-La2О3-Р2О5-ZSM-Al2O3 has the highest hydro desulfurizing activity. At hydro processing of straight-run diesel fraction on this catalyst under optimal conditions the sulfur content decreases from 0.6400 % to 0.0740 % and during hydro processing of a straight-run diesel fraction with a higher sulfur content 0.8042% - up to 0.053%, which, apparently, is associated with the presence in the feedstock of various types of organosulfur compounds. The lowest pour point and cloud point under optimal conditions reaches minus 39.6oС and minus 30.5oС respectively. Thus, developed modified zeolite-containing catalysts for the hydro processing of gasoline and diesel fractions carry out hydro processing, hydro isomerization and hydrogenation in one stage. The developed catalysts make possible to obtain high-octane low-sulfur gasoline and low-solidification low-sulfur diesel fuel.

Influence of Desulfurization with Fe2O3 on the Reduction of Nickel Converter Slag

Generally in the nickel converter slag, metals are mainly in the form of sulfides, which are difficult to separate from slag. Although metal oxides in the slag, such as NiO, CoO, and Cu2O, are easily reduced into metal using carbon, the presence of sulfur inhibits the reduction reaction. In this study, the addition of Fe2O3 to nickel converter slag produced desulfurized slag, which enhanced the carbothermal reduction process. Increasing the desulfurization rate promoted the conversion of sulfides into oxides in slag, which significantly increased the activity of NiO, Cu2O, and Fe2O3. However, the residual sulfur content had no significant effect on the activity of FeO and CoO, due to the high initial FeO content and cobalt existing mainly in the form of oxides. The optimum addition of Fe2O3 was 15.0 g per 100 g nickel slag, while the desulfurization ratio was 36.84% and the rates of nikel, cobalt and copper recovery were 95.33%, 77.73%, and 73.83%, respectively.

CMSX-486® Alloy Update

Modern turbine engine performance and life cycle requirements demand single crystal (SX) superalloy turbine airfoil and seal components. However, complex SX components, such as vane segments, can result in severe manufacturing cost challenges due to low manufacturing yield. As presented at TURBO EXPO 2002 and 2006, these requirements led to the development of CMSX-486® alloy, a grain boundary strengthened SX superalloy with improved creep-rupture strength over SX CM 186 LC® alloy. This paper will review the unique properties that make this alloy desirable, with particular attention to ongoing developments. Significant market interest has resulted in additional property evaluation, including strain-controlled low cycle fatigue testing which has produced fatigue lives similar to HIP’ed and solutioned CMSX-4® SX alloy at 1038°C. This was surprising considering the non-homogeneous microstructure of CMSX-486 alloy, which is used in the as-cast + double aged heat treat condition. Also, burner rig dynamic, cyclic oxidation and Type I hot corrosion results will be presented for CMSX-486 (SLS) [La+Y] alloy in comparison to CMSX-4, CMSX-4(SLS)[La+Y] and CMSX-486 alloys. Scanning electron microscopy analysis shows residual sulfur and phosphorus in CMSX-486 (SLS) [La+Y] are tied up as Y and La carbo-sulfides and phosphides.

Fabrication of transparent Sc2O3 ceramics with powders thermally pyrolyzed from sulfate

Scandia (Sc2O3) is a ceramic material that shows interesting thermal and optical properties, but is difficult to grow as single crystals. As an alternative, in this work we fabricated polycrystalline Sc2O3 transparent ceramics via vacuum sintering, using powders thermally pyrolyzed at 1200 °C from a scandium sulfate salt, Sc2(SO4)3 · 7.8H2O, that we prepared. Characterization of the powders was achieved by differential thermal analysis/thermogravimetry, x-ray diffractometry, Brunauer–Emmett–Teller analysis, and field-emission scanning electron microscopy. Sintering behaviors of the Sc2O3 powders were studied in air via dilatometry. The sulfate salt transforms to oxide at temperatures ≥1000 °C, and the best pyrolysis temperature for transparent ceramics fabrication is 1200 °C, at which the resultant Sc2O3 powder is good in dispersion, ultrafine in particle size (∼80 nm), and almost free from residual sulfur. Transparent ceramics were fabricated from this powder via vacuum sintering at 1625 °C or above. The ceramics sintered at 1700 °C for 4 h exhibit an in-line transmittance of approximately 56–58% in the visible light region at a sample thickness of 1.0 mm.