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Two series of Ni-Mo catalysts were prepared using Al2O3 and TiO2 supports. Ni/ (Ni+Mo) ratio of the catalysts was varied, while a total metal loading of Ni and Mo was kept constant. Sulfiding conditions were optimized to give superior catalytic activities. After sulfiding, model test reactions were carried out to evaluate hydrogenation (HY), hydrocracking (HC) and hydrodesulfurization (HDS) activities of the sulfide catalysts.The highest HY activities of Al2O3 and TiO2 supported catalysts were obtained when the Ni/ (Ni+Mo) ratios were 0.25 and 0.12, respectively, showing different interaction between support and active metals. XPS measurements revealed that the atomic ratio of active metal sulfide {NiS/ (NiS+MoS2)}, which gave the highest HY activities, was 0.2 on both supports. This indicates that sulfided active metals such as NiS or MoS2 play an important role for the formation of HY active sites.Both catalysts supported on Al2O3 and TiO2 showed the highest HDS activities when the NiS/ (NiS+MoS2) ratio was 0.4. This ratio is different from that obtained in HY measurements. While HC activities of the two series of sulfide catalysts decreased with increasing of Ni loading.These results clealy show that HY, HC and HDS active sites of Ni-Mo sulfide catalysts are different each other and that proper selection of each active metal loading is required for preparing highly selective catalysts.

Thermodynamic analyses were done for better understanding of the structural changes in iron based coal liquefaction catalysts during sulfidation and oxida-tion. Chemical potential diagrams were used to evaluate the stability/reactivity of several iron phases such as Fe, Fe3O4 (magnetite), Fe2O3 (hematite), Fe0.877S (Pyrrhotite), FeS2 (phyrite), FeSO4, and Fe2 (SO4) 3. These analyses indicated that most of the iron starting materials would be converted into thermodynamically stable phase Fe0.877S under typical coal liquefaction conditions, i.e., reaction temperature of 698K under reducing/sulfiding conditions. However, the sulfidation paths were quite different in Fe2O3 and FeSO4 as the starting materials, and were influenced significantly by the sul-fidation conditions, such as temperature, P (H2S) /P (H2) and P (H2O). These analyses suggested that steaming conditions would facilitate the sulfidation, but cause the gas phase transport of hydrated compounds, which might be one of the reasons for catalyst agglomeration.

In order to make clear the behavior of coal mineral remaining in coal liquid on the hydrotreating catalyst, a Wandoan coal derived liquid containing high contents of liquefaction solid was hydroprocessed over the Ni-Mo-γ-Al2O3 catalyst having bimodal pore size distributions.In these liquefaction residues, kaolin and quartz were not chemically altered and magnetite was undergone chemical transformation to pyrrhotite during hydroprocessing. From the shell like deposits of these metals around the spent cata lysts, these matters might be finely dispersed particles that had equivalent spherical diameter larger than about 1-2μm, which corresponded to maximum size of macropore in used catalysts.Titanium and calcium metals, which were more concentrated in THF insoluble residue in feed coal liquid, were tend to accumulate in preasphaltene after hydro processing. Furthermore from the more penetrated depth profile of titanium and calcium metals, these metal containing matters might have equivalent spherical diam eter larger than about 0.6μm and 4.4nm micro-pore diameter were too small to be utilized against carbonaceous material deposits. Because active sites might be occupied with sodium metal, which interacted more strongly with those than titanium and calcium metals, titanium and calcium metals migrated more deeper on the catalyst pore walls by surface diffusions.As a result, silicon and iron metals were tend to plug the catalyst pore mouth and sodium, alkaline earth metals and titanium metals were tend to poison active sites and change micro-pore structure.

The deactivation behavior of molybdenum catalysts used for hydrotreating coal-derived liquids is reviewed to obtain information for the design concept for long-life catalysts. Causes for the catalyst deactivation are fundamentally similar to those for catalysts us-ed in petroleum hydroprocessing. However, the deactivation patterns for the catalysts in coal-derived liquid hydroprocessing was different from that found in petroleum hydroprocessing. This is mainly due to differences between coal liquid and petroleum feeds. Characterization of spent catalysts revealed certain differences in features of metal and carbonaceous deposits resulting from the use of coal liquids and petroleum. The changes in physical and chemical pro-perties of used hydroprocessing catalysts are discussed for coal liquids and petroleum, respec-tively. Changes in the local structure of active metals were found to decrease catalyst activity during coal liquid hydrotreating. Based on understanding of the catalyst deactivation, remedies for catalyst deactivation in connection with the development new types longife catalysts are also discussed.