Catalyst – solid sorbent – or support therefor: product or process – Catalyst or precursor therefor – Halogen or compound containing same
Patent
1997-12-15
1999-07-13
Wood, Elizabeth D
Catalyst, solid sorbent, or support therefor: product or process
Catalyst or precursor therefor
Halogen or compound containing same
502224, 502226, 502227, 502228, 502229, 502231, B01J 2706, B01J 2713, B01J 27125, B01J 27135
Patent
active
059226390
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a catalyst comprising a matrix consisting of a mixture of .eta. transition alumina and .gamma. transition alumina, or in addition, at least one doping metal chosen from the group made up of titanium, zirconium, hafnium, cobalt, nickel, zinc, the lanthanides and the alkali and alkaline-earth metals, at least one halogen, at least one noble metal and at least one promoter metal.
The invention also relates to the preparation process for this catalyst. This catalyst may, in particular, be used for the conversion of hydrocarbons. This process may, particularly, be used for catalyst reforming processes.
2. Description of the Background
Catalyst reforming is a process which can be used to obtain improved octane ratings of petroleum fractions, in particular of heavy distillation gasoline by conversion of n-paraffins and naphtenes into aromatic hydrocarbons.
Catalyst reforming therefore entails the conversion firstly of C.sub.7 -C.sub.10 n-paraffins into aromatics and light paraffins, and secondly of C.sub.7 -C.sub.10 naphthenes into aromatics and light paraffins. These reactions are illustrated in particular by the conversion through dehydrogenation of cyclohexanes and dehydroisomerization of alkyl cyclopentanes to give aromatics, for example methyl cyclohexane giving toluene, and by the conversion through cyclization of n-paraffins into aromatics, for example n-heptane giving toluene.
During catalytic reforming, cracking reactions of heavy n-paraffins into light paraffins also take place, leading in particular to C1-C4 products, chiefly propane and isobutane: these reactions are detrimental to the yield of reformed product.
Finally, coke formation also takes place through condensation of aromatic nuclei to form a solid product rich in carbon which is deposited on the catalyst.
These reforming catalysts are extremely sensitive, in addition to coke, to various poisons likely to deteriorate their activity: in particular sulphur, nitrogen, metals and water.
When coke is deposited on the surface of the catalyst, it leads to loss of activity in the course of time which, at higher operating temperatures, produces a lower yield of reformed product and a higher yield of gas.
On this account, and taking into consideration the regeneration of the catalyst, the process of catalytic reforming can be implemented in two different manners: in semi-regenerative or cyclical manner and in continuous manner. In the former, the process is carried out in a fixed bed, and in the latter in a mobile bed.
In the semi-regenerative process, to offset the loss of activity of the catalyst, the temperature is gradually increased, then the installation is stopped to proceed with regenerating the catalyst by eliminating the coke. In cyclical reforming, which is in fact a variant of the semi-regenerative process, the installation comprises several reactors in series and each is put out of operation in turn, the coke deposits are eliminated from the catalyst placed out of circuit and the catalyst is regenerated while the other reactors remain in operation.
In continuous reforming, the reactors used are mobile bed reactors operating at low pressure (less than 15 bars), which allows for considerably improved yields of reformed product and hydrogen by promoting aromatization reactions to the detriment of cracking reactions, coke formation on the other hand being greatly accelerated. The catalyst passes through the reactors then through a regenerating section.
On account of the chemical reactions that take place during reforming processes, a bifunctional catalyst must be used which combines two types of activity namely the hydrogenating-dehydrogenating activity of a metal, in particular a noble metal such as platinum, possibly associated with other metals such as rhenium or tin, so-called promoter metals, this metal being deposited on the surface of a porous matrix. This matrix of alumina contains a halogen, preferably a chlorine, which provides the necessary acidi
REFERENCES:
patent: 3415737 (1968-12-01), Kluksdahl
patent: 3686340 (1972-08-01), Patrick et al.
patent: 3700588 (1972-10-01), Weisang et al.
patent: 3839192 (1974-10-01), Hayes
patent: 4105590 (1978-08-01), Koberstein et al.
patent: 4401557 (1983-08-01), Juguin et al.
patent: 4602000 (1986-07-01), Dupin et al.
patent: 5849657 (1998-12-01), Rotgerink et al.
Alario Fabio
Deves Jean-Marie
Euzen Patrick
Institut Francais du Pe'trole
Wood Elizabeth D
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