The major technical objectives of this program are threefold: (1) to develop the design tools and a fundamental understanding of the fluid dynamics of a slurry bubble column reactor to maximize reactor productivity, (2) to develop the mathematical reactor design models and gain an understanding of the hydrodynamic fundamentals under industrially relevant process conditions, and (3) to develop an understanding of the hydrodynamics and their interaction with the chemistries occurring in the bubble column reactor. Successful completion of these objectives will permit more efficient usage of the reactor column and tighter design criteria, increase overall reactor efficiency, and ensure a design that leads to stable reactor behavior when scaling up to large diameter reactors.

The major technical objectives of this program are threefold: (1) to develop the design tools and a fundamental understanding of the fluid dynamics of a slurry bubble column reactor to maximize reactor productivity; (2) to develop the mathematical reactor design models and gain an understanding of the hydrodynamic fundamentals under industrially relevant process conditions; and (3) to develop an understanding of the hydrodynamics and their interaction with the chemistries occurring in the bubble column reactor. Successful completion of these objectives will permit more efficient usage of the reactor column and tighter design criteria, increase overall reactor efficiency, and ensure a design that leads to stable reactor behavior when scaling up to large diameter reactors. The main part of this report describes tracer studies of slurry bubble column hydrodynamics during methanol synthesis.

Results from a series of experiments designed to demetallize coal liquefaction products, which include Solvent-Refined Coal from the Wilsonville Advanced Coal Liquefaction Research and Development Facility (ACLRDF), Solvent-Refined Coal from Fort Lewis, and a process solvent from the Wilsonville ACLTF, indicate that the trace metals in coal-derived residuum are associated with heavy (less soluble) fractions of the feedstocks, in particular preasphaltene. This parallels speculations found in the literature. These conclusions are based on trace metal analyses of fractions obtained from methods such as filtration, Soxhlet extraction, solvent coprecipitation, supercritical destraction, and adsorption on alumina. These results suggest that such physical methods can reduce the concentration of the trace metals but only with simultaneous removal of asphaltenes and preasphaltenes. Total or near total elimination of metals is not possible without altering the organic makeup of the coal residuum. Titanium, in particular, appears to be complexed with heteroatom(s) contained in the polar fractions and hence is difficult to remove without removal of the polar fractions. A thermal process or a chemical technique based on selective chelating of these trace metals will probably be required for total removal of trace metals from these coal liquefaction products. 56 refs., 8 figs., 18 tabs.

Current emphasis in many direct coal liquefaction processes involves a two-stage approach consisting of a thermal and catalytic stage. In this scheme, the catalytic second stage is used to upgrade the thermally generated coal liquids and to produce a good recycle solvent that promotes the thermal-dissolution processes occurring in the first stage. The catalysts currently used in the second stage are not optimized for use with coal liquids. Therefore, an investigation was conducted to assess the relative activity of catalysts with varying Ni/Mo or Ni/W atomic ratios in these systems. Initial activities of these catalysts were obtained using a 50/50 mixture of coal-liquid residuum and process solvent. The results indicate that the Ni-Mo catalysts are superior to the Ni-W catalysts for upgrading coal liquids. The results also indicate that changing the Ni/Mo and Ni/W ratios has only a moderate effect on the hydrogenation and denitrogenation activity of the catalysts but a somewhat larger effect on desulfurization activity and the conversion of coal liquids to cyclohexane soluble products. Under the experimental conditions tested, the ability of the catalyst to convert coal-liquid residuum to -340/sup 0/C distillate is small and is not affected by the Ni/Mo or Ni/W atomic ratio. The optimummore » activity of the Ni-Mo catalysts for hydrogenation, denitrogenation, desulfurization, and conversion of coal-liquid residuum to cyclohexane soluble products occurs at a Ni/(Ni + Mo) atomic ratio of about 0.4, while that of the Ni-W catalysts occurs at a Ni/(Ni + W) atomic ratio of about 0.5. 24 refs., 10 figs., 8 tabs.« less

AbstractBei Katalysatoren mit I5 Gew.‐°/o MoO3 und 0 bis 8 Gew.‐°/o C00 (Co‐Promoter) wurden in der Oberfläche CoMoO4 und nichtteduzierbare Coztlonen tetragonaler Symmetrie sowie bei 7‐8% C00 zusätzlich Co3O4‐Kristallite nachgewiesen ( u.a. durch l.5‐keV‐"He ‐lSS).

Synthesis gas was reacted over different compositions of iron-manganese Fischer-Tropsch catalysts in a slurry reactor. The reactor operates in a back-mixed mode with a continuous flow of feed gas through the catalyst suspended in the liquid medium. Four catalysts with iron-manganese ratios of 57/43, 44/56, 22/78, and 10/90 were investigated at identical process conditions after a standard activation procedure. With time on stream for each catalyst system, hydrogenation of olefins occurred, along with olefin isomerization reactions. Activity, selectivity, and stability are discussed in general. Analyses of used catalyst samples are also reported.

Laser Raman spectroscopy, X-ray photoelectron spectroscopy, low-energy ion-scattering spectroscopy, and X-ray diffraction have been used to characterize a series of Co-Mo/Al/sub 2/O/sub 3/ catalysts containing 15 wt% MoO/sub 3/ and 0 to 8 wt% CoO in their oxide, reduced, and sulfided forms. These data show that the catalyst surface contains CoMoO/sub 4/ and irreducible Co/sup 2 +/ ions of tetrahedral symmetry when the CoO concentration is 0 to 6%. With 7 to 8% CoO, additional surface species includes Co/sub 3/O/sub 4/ crystallites on the ..gamma..-Al/sub 2/O/sub 3/ surface. Formation of Co/sub 3/O/sub 4/ coincides with an increased Mo reducibility and a decreased BET surface area. These results are compared to previously published data on Co-Mo/Al/sub 2/O/sub 3/ and suggest that the state of dehydration-dehydroxylation of the Al/sub 2/O/sub 3/ surface before impregnation of Co and Mo affects their subsequent speciation. Autoclave studies investigating the hydrodesulfurization (HDS) and hydroconversion of coal using these catalysts are also reported. Significance of the surface speciation with respect to these activity studies is discussed. 36 references, 12 figures, 5 tables.

Synthesis gas was reacted over different compositions of iron-manganese Fischer-Tropsch catalysts in a slurry reactor. The reactor operates in a back-mixed mode with a continuous flow of feed gas through the catalyst suspended in the liquid medium. Four catalysts with iron-manganese ratios of 57/43, 44/56, 22/78, and 10/90 were investigated at identical process conditions after a standard activation procedure. With time on stream for each catalyst system, hydrogenation of olefins occurred, along with olefin isomerization reactions. Activity, selectivity, and stability are discussed in general. Analyses of used catalyst samples are also reported. 20 refs., 2 figs., 4 tabs.

MoS2 has been prepared in two new physical forms by treatment of sulfided Ni-Mo/Al2O3 catalysts with hydrofluoric acid. The first consists of O.2 × 3 mm pellets which do not have the cleavage present in natural molybdenite but upon crushing produce irregular shiny particles. These highly reflecting particles are crystalline and contain five to ten MoS2 layers per crystallite. In the second form essentially all the MoS2 is present as single layers either supported on or mixed with carbon.

The visible and near-infrared spectra were determined for small quantities of Cu(II) in nitrate-containing glasses. The ligands around the Cu(II) ion were changed from all nitrate to mixed nitrate-chloride. Changes in the spectra arising from these changes in the ligands are discussed. The Cu(II) ion ligand field bands can be interpreted as resulting from distorted octahedral symmetry and change little from one glass to another. However, large changes in the charge transfer band were produced by varying the Cu(II) and chloride ion concentrations.

The enthalpy changes associated with annealing of glass were studied in simple and mixed alkali silicate glasses. The data indicate that during prolonged annealing the glass comes to a metastable equilibrium state and has a unique heat of solution which depends on its fictive temperature. The heats of solution of these glasses show a linear dependence on fictive temperature, and the magnitude of this dependence is related to the molar volume of the glass. The significance of these heat effects is discussed. The maximum heat effects which can occur on annealing sodium silicate glasses were measured and were approximately half as large as the enthalpy changes associated with the structural arrangements that occur during crystallization of these glasses.

The effects of pressure up to 50 kbar and of compositional changes on the absorption spectra of a number of chromium-containing silicate, phosphate, and borate glasses were observed. The spectra were analyzed into their component bands, and ligand-field theory was used to interpret the results to obtain information about the local symmetry, distortion, and local compressibility of the chromium sites. The absorption properties are explained by assuming that, on the average, the trivalent chromium ions are surrounded by six oxygen ions in an octahedral arrangement. The behavior of the spectra indicates that a random distribution of Cr–O distances about an average Cr–O distance exists and that only small disortions from cubic symmetry occur. The variation of the ligand-field parameters and the compressibilities of the sites depends mainly on the number of oxygen ions per unit volume in the glass, whether the changes are induced by external pressure or by compositional changes. Those glasses with a more open oxygen packing exhibit smaller crystal-field strengths, larger compressibilities, and larger distortions from octahedral symmetry than do the more densely packed glasses. Also, the compressibilities of the chromium sites are much less than the bulk compressibilities of the glasses.