Browsing by Subject "Synthetic fuels"

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    The oligomerization of propene over nickel synthetic mica-montmorillonite
    (1987) Jacobs, Lester Lance; O'Connor, Cyril; Kojima, M
    The catalytic oligomerization of propene to liquid fuels using synthetic mica montmorillonite (SMM) as well as the effect of incorporating nickel into the lattice and nickel, cobalt and zinc into the interlayer spaces was investigated. NiSMM is more active for propene oligomerization than SMM, although the product selectivity (60% of the oligomers boiled at above 453 K) is similar. The increase in activity of NiSMM is attributed to an increase in the surface acidity of the catalyst. The maximum activity over the nickel exchanged catalyst occurs at a nickel loading of 0.057 wt %. It is proposed that the bond strength of the acidic hydroxyl groups are perturbed by the polarizing effect of the divalent cation (Co, Zn or Ni) present in the interlayer spaces of SMM. The reduction of nickel, ion exchanged into SMM, removes the induction period associated with SMM and increases the catalyst lifetime. However, reduction of the lattice nickel results in a decrease in catalyst lifetime although the Bronsted acidity has increased. It is proposed that the metallic nickel present in reduced NiSMM may promote dehydrogenation of high molecular weight hydrocarbons thus causing rapid deactivation of the catalyst by increasing the formation of "graphitic" coke. The lifetime of NiSMM is greatly reduced by using a wet propene feed and reacting at higher temperatures (443 K) due to the generation of Bronsted sites and increased coke formation rates, respectively. Deactivation of the catalyst is associated with a "graphitic" coke build up. The RON of the petrol fraction is 94.5 and the hydrogenated diesel fraction has a cetane number less than 35.
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    Open Access
    Synthesis, characterisation and catalytic testing of pillared clays and lanthanum exchanged ZSM-5 for hydrocarbon conversion
    (1989) Hartford, Radleigh; O'Connor, Cyril T; Kojima, Masami
    Pillared clays present interesting possibilities for use as acid catalysts. The present research investigated the effect that pillaring has on the physical and catalytic properties of some smectite clays. The effect of using a hydroxy-Al solution to pillar a predominantly octahedrally ,substituted clay (montmorillonite) and a tetrahedrally substituted clay (beidellite) were compared. The effects of pillaring tetrahedrally substituted clays with different swellable properties (beidellite, SMM, and Ni-SMM) were investigated. In an attempt to enhance the acidic properties of the pillars, montmorillonite was pillared with a hydroxy-Al solution containing tetraethyl orthosilicate. Montmorillonite was also pillared with a hydroxy-Ni/Al solution in an effort to produce a clay with an increased pillar density. The pillared and unpillared clays were characterised using x-ray diffraction, surface area measurements, thermogravimetric analysis and ammonia TPD. The possible shape selective properties of the different clays for the conversion of trimethylbenzene were investigated, and the catalytic activities and product selectivities of these clays for high pressure propene oligomerisation were studied.