Restrictive liquid-phase diffusion and reaction in bidispersed catalysts

Journal Article · Thu Aug 01 04:00:00 EDT 1991 · Industrial and Engineering Chemistry Research; (United States)

DOI:https://doi.org/10.1021/ie00056a002· OSTI ID:7273900

Lee, S Y; Seader, J D ^[1]; Tsai, C H; Massoth, F E ^[2]

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1. Utah Univ., Salt Lake City, UT (United States). Dept. of Chemical Engineering
2. Utah Univ., Salt Lake City, UT (United States). Dept. of Fuels Engineering

In this paper, the effect of bidispersed pore-size distribution on liquid-phase diffusion and reaction in NiMo/Al{sub 2}O{sub 3} catalysts is investigated by applying two bidispersed-pore-structure models, the random-pore model and a globular-structure model, to extensive experimental data, which were obtained from sorptive diffusion measurements at ambient conditions and catalytic reaction rate measurements on nitrogen-containing compounds. Transport of the molecules in the catalysts was found to be controlled by micropore diffusion, in accordance with the random-pore model, rather than macropore diffusion as predicted by the globular-structure model. A qualitative criterion for micropore-diffusion control is proposed: relatively small macroporosity and high catalyst pellet density. Since most hydrotreating catalysts have high density, diffusion in these types of catalysts may be controlled by micropore diffusion. Accordingly, it is believed in this case that increasing the size of micropores may be more effective to reduce intraparticle diffusion resistance than incorporating macropores alone.

• OSTI ID: 7273900
• Journal Information: Industrial and Engineering Chemistry Research; (United States), Journal Name: Industrial and Engineering Chemistry Research; (United States) Vol. 30:8; ISSN 0888-5885; ISSN IECRE
• Country of Publication: United States
• Language: English

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