Petroleum reforming octane rating

Reforming (Section 2 16) Step in oil refining in which the pro portion of aromatic and branched chain hydrocarbons in petroleum is increased so as to improve the octane rating of gasoline... 

Another property of zeolites is the high conversion rates in the channel system. It was also observed that with different spatial configurations of channels, cavities, windows, etc, the catalytic properties are changed and the selectivity orientates toward less bulky molecules due to limitation in void volume near the active sites or to resistance to diffusivity. This feature termed shape-selectivity, was first proposed by McBain (20) demonstrated experimentaly by Weisz et al (21) and reviewed recently (22). For instance CaA zeolite was observed to give selective dehydration of n-butanol in the presence of more bulky i-butanol (23) while CaX non selective zeolite converted both alcohols. In a mixture of linear and branched paraffins, the combustion of the linear ones was selectively observed on Pt/CaA zeolite (24). Moreover, selective cracking of linear paraffins was obtained from petroleum reformate streams resulting in an improvement of the octane number known to be higher for branched paraffins and for aromatics than for linear paraffins. Shape selectivity usually combines acidic sites within... 

A catalyst consisting of platinum dispersed on an acidic alumina is a very effective dual function catalyst, used in petroleum reforming of naphtha and also for paraffin isomerization. The conversion of naphtha constituents such as methylcyclopentane, MCP, to benzene, B, is desired in order to increase octane rating. The reaction pathway for conversion of MCP to B is illustrated in Fig. 3 . MCP is first dehydrogenated on a platinum site to the olefin of the same structure. The olefin then transfers to an acidic site where it is isomerized to cyclohexene. This olefin proceeds to a platinum site where it is dehydrogenated to B and H2. In the diagram, vertical movement represents hydrogen subtraction or addition and horizontal movement represents isomerization. 

Sasolinc A mixture of alkanes with chain lengths of between five and ten carbon atoms used as a fuel for internal combustion engines. It is obtained from the fractional distillation of petroleum and from cracking and reforming of hydrocarbons. See octane rating. 

Reforming reactors are used to increase the octane number of petroleum, In a reforming process 20,000 barrels of petroleum are to be processed per day. The corresponding mass and molar feed rates are 44 kg/s and 440 mol/s, respectively. In the reformer, dehydrogenation reactions such as... 

The studies of n-heptane and methylcyclopentane conversion provide insight into the advantages of platinum-iridium and platinum-rhenium catalysts over catalysts containing only one of the transition metal components, that is, platinum, iridium, or rhenium. If, for example, we consider an iridium-alumina catalyst for the reforming of a petroleum naphtha fraction, we find that it produces a substantially higher octane number reformate than a platinum on alumina catalyst under normal reforming conditions. The iridium-alumina catalyst will also exhibit a lower rate of formation of carbonaceous residues on the surface, with the result that the maintenance of activity with time will be much superior to that of a platinum-alumina catalyst. 

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