Journal of the Japan Institute of Energy
Online ISSN : 1882-6121
Print ISSN : 0916-8753
ISSN-L : 0916-8753
Volume 75 , Issue 4
Showing 1-3 articles out of 3 articles from the selected issue
  • Kazumasa NARA, Masateru KUMOSHIKARI, Suehiko YOSHITOMI, Toshio SATO, Y ...
    1996 Volume 75 Issue 4 Pages 238-246
    Published: April 20, 1996
    Released: June 28, 2010
    JOURNALS FREE ACCESS
    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.
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  • Kouichi MIURA, Taisuke MAKI, Kazuhiro MAE
    1996 Volume 75 Issue 4 Pages 247-256
    Published: April 20, 1996
    Released: June 28, 2010
    JOURNALS FREE ACCESS
    The deposits of Orinoco tar in Venezuela are estimated to amount to 80 percent of the deposits of crude oil in the Middle East. To examine the possibility for utilizing the Orinoco tar as chemical feedstocks, pyrolysis behavior of Orinoco tar and Orinoco tar-water emulsion (Orimulsion) was examined using a Curie point pyro-lyzer (CPP) and an entrained bed reactor. The gasification reactivity of the coke formed during the pyrolysis was also measured. Heavy tar was produced in about 80% yield from the Orinoco tar through the primary pyrolysis reaction regardless of temperature and pressure. The heavy tar, however, could be converted to valuable chemicals such as hydrocarbon gases, and BTX (benzene, toluene, xylene) in high yield through secondary gas phase reaction. At 800°C the sum of the yields of methane, ethylene, BTX and naphthalene reached more than 50%. Two kinds of coke were found to be formed: one was produced through the primary reaction, and the other was produced through the secondary gas phase reaction from aromatic compounds such as naphthalene. The yield of the former one was little dependent on pyrolysis conditions, whereas the yield of the latter one increased with the increase in the temperature and/or the residence time. At 1200°C the total coke yield more than 60%. The gasification rate of the coke was only one-seventh of that of a coal char in a steam atmosphere even at 1000°C.
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  • Osamu OKUMA, Kaoru MASUDA, Noriyuki OKUYAMA, Tatsuo HIRANO
    1996 Volume 75 Issue 4 Pages 257-264
    Published: April 20, 1996
    Released: June 28, 2010
    JOURNALS FREE ACCESS
    A solvent de-ashing under high temperature and high pressure has been adopted by Nippon Brown Coal Liquefaction Co., This is applied in the two-stage brown coal liquefaction (BCL) process to remove ash from the heavy product (coal liquid bottom, CLB, b. p.>420°C) in primary hydrogenation (liquefaction).
    Naphthas obtained from the primary and secondary hydrogenations, primary naphtha and secondary naphtha, were analysed, and their extraction ability of CLB were measured under high temperature and pressure conditions. These results make clear that the secondary naphtha, which contains cycloparaffins of ca. 60%, is unsuitable for the de-ashing solvent because it provides lower extract yield and sticky residue from CLB at above 170°C. The primary naphtha provides higher extract yield and the residue which is handled as a slurry. The primary naphtha corresponding to toluene is easily prepared by distillation. The extraction ability of the primary naphtha is represented by its density at ambient temperature (20°C). The equation which estimates extract yield from CLBs is introduced by using the density of naphtha and the contents of asphaltene (HI-BS), preasphaltene (BI-PS) and pyridine-insoluble (ash) as parameters.
    It is also confirmed that the ash in the CLBs is removed by settling in the primary naphtha at 250°C. The naphtha is better as a de-ashing solvent than toluene because it copes with change in CLB properties by controlling its density by distillation.
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