Leo E. Makovsky

Raman spectra of supported molybdena catalysts: II. Sulfided, used, and regenerated catalysts☆

Abstract Raman spectroscopy has been used to investigate the structural changes that two supported molybdenum oxide catalysts undergo upon specific chemical treatments. Molecular MoS2 structures are indicated after sulfidation by a mixture of H 2 H 2 S . Catalyst samples used in a coal hydrodesulfurization process yield spectra dominated by intense scattering from carbon deposited in the pores of the catalyst. Spectra of used catalyst samples, subjected to controlled air-firing to 600 °C, show that all of the spectral features of the unused catalyst are not recovered after this “regeneration” procedure.

A surface spectroscopic study of Coz.sbnd;MoAl2O3 catalysts using ESCA, ISS, XRD, and Raman spectroscopy, I

Abstract Laser Raman spectroscopy, X-ray photoelectron spectroscopy, low-energy ion-scattering spectroscopy, and X-ray diffraction have been used to characterize a series of Coz.sbnd;Mo Al 2 O 3 catalysts containing 15 wt% MoO 3 and 0 to 8 wt% CoO in their oxide, reduced, and sulfided forms. These data show that the catalyst surface contains CoMoO 4 and irreducible Co 2+ ions of tetrahedral symmetry when the CoO concentration is 0 to 6%. With 7 to 8% CoO, additional surface species includes Co 3 O 4 crystallites on the γ-Al 2 O 3 surface. Formation of Co 3 O 4 coincides with an increased Mo reducibility and a decreased BET surface area. These results are compared to previously published data on Coz.sbnd;Mo Al 2 O 3 and suggest that the state of dehydration-dehydroxylation of the Al 2 O 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.

A spectroscopic study of the effect of H2O and NiO on the surface structure of NiOMoO3Al2O3

Abstract The molecular speciation of two sets of NiOMoO 3 Al 2 O 3 catalysts, containing 0–7% NiO with 7.5% MoO3 or 15% MoO3, is examined spectroscopically as a function of in situ O2 calcination-H2O exposure cycles. The sensitivity of ion scattering spectrometry to detect Mo in these catalysts is dependent upon their exposure to H2O but is not dependent upon NiO concentration. This dependence, in conjunction with in situ Raman spectroscopic data, is used to describe sites of interaction of Ni or H2O with the surface molybdate. These NiMo and H2OMo interactions are shown to be distinct and are discussed in relation to previously published data on the structure and HDS activity Of NiOMoO 3 Al 2 O 3 Catalysts.

Supported transition metal compounds: I. A new method for the preparation of alumina-supported iridium and osmium carbonyls☆

An extraction technique for the preparation of alumina-supported iridium and osmium carbonyls from Ir4(CO)12 and Os3(CO)12 is reported. It is concluded that the metal carbonyl species produced are highly dispersed and of small particle size (less than 50 A diameter) in contrast to the large crystallites of iridium and osmium carbonyls obtained by either the dry grinding or wet impregnation techniques. Partial decarbonylation of the metal carbonyl species can be effected by varying the conditions of the preparation and by heating the samples in air, the species [Ir(CO)2]+ and [Os(CO)n]2+, n = 2,3, have been identified from their infrared spectra. Strong interactions between the metal carbonyl species and the alumina support are present.

BLAST FURNACE GRANULAR COAL INJECTION AT BETHLEHEM STEEL'S BURNS HARBOR PLANT

This paper discusses the demonstration of the British Steel/CPC-Macawber Blast Furnace Granular Coal Injection (BFGCI) technology that was installed on the blast furnaces at Bethlehem Steels Burns Harbor Plant in Indiana as a highly successful Clean Coal Technology project, cofunded by the U.S. Department of Energy. In the BFGCI process, granular coal (10%–30% through a 200-mesh screen) is injected into a blast furnace as a fuel supplement to decrease coke requirements, thus reducing costs. Tests run to determine the effect of process variables on furnace operations showed that granular coal works as well as pulverized coal and is easier to handle and cheaper to produce because of reduced grinding costs.