Aromatic hydrocarbons alkylation and liquid-solid circulating fl

Chemistry of hydrocarbon compounds – Aromatic compound synthesis – By condensation of entire molecules or entire hydrocarbyl...

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Details

585447, 585921, 585925, 208134, 422144, C07C 268, C10G 3504, F27B 1508

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active

057896402

DESCRIPTION:

BRIEF SUMMARY
FIELD OF THE INVENTION

The present invention relates to a continuous alkylation process and a liquid-solid circulating fluidized bed system for the continuous alkylation process. More specifically, the invention relates to a continuous alkylation process of aromatics or their derivatives in the presence of a solid acid catalyst and a liquid-solid circulating fluidized bed system for such a process in which the reaction of the reactants and the regeneration of the used solid acid catalyst proceed continuously.


BACKGROUND OF THE INVENTION

Alkylation reaction is one of the most important reactions in the petrochemical industry, for example, the product of the alkylation of benzene with propylene is the raw material for propanone and phenol; the alkylation of iso-butane with butene produces high octane number gasoline; and the alkylation of benzene with long chain olefins (C.sub.10 -C.sub.18 olefins) produces the raw materials for detergents and surfactants. The previous catalysts for the above processes are liquid catalysts, for example, H.sub.2 F, H.sub.2 SO.sub.4, H.sub.3 PO.sub.4, AlCl.sub.3, ZnCl.sub.2, and so on. However, the use of these catalysts brings about a lot of problem such as the separation of catalyst from products, treatment of the used catalyst, corrosion to the equipment and the harm to the health of the operators. Therefore, in recent years, it is an interesting subject to develop new solid catalysts to replace the above liquid catalysts for the alkylation processes.
The solid acid catalysts which have been proposed for the alkylation process are zeolite molecular sieves, such as HX, HY, HZSM-5, USY and REHY; halogen-containing cation exchanged resins, halogen-containing superacids, superacids of SO.sub.4.sup.2- /M.sub.x O.sub.y type, and composite oxide superacids. These solid catalysts are susceptible to deactivation due to the deposition of coke formed from the polymerization of the olefins on the catalyst surface , hence, the activity of these catalysts will decrease quickly, especially, for the catalyst with high activity. This means that the solid catalysts will be run only with a very low activity during the process if no special treatment is given to these used catalysts. Although different techniques, such as the introduction of the Group VIII elements or the rare earth elements into the catalyst, have been used to prevent coke deposition on the catalyst and to improve the service life of the catalysts, the results are not satisfactory.
Another approach to the problem is to develop a new process, in which the coke deposited catalyst are regenerated timely. To satisfy the requirement of the process wherein the alkylation reaction in the presence of a solid catalyst and the regeneration of the used solid catalyst (referred to as reaction-regeneration cycle hereafter) occur alternatively, it is critical to develop new process equipment in which the above process can be realized (Vora, B. V. et al., Tenside Surfactant Detergent, 28(4), 287-294, 1991). It has been reported that the fixed bed and continuously stirred batch reactors have been used for such a process.
In the fixed bed reactor, when the activity of the catalyst decreases to a certain level, the reactor will be switched to regeneration phase. The regeneration proceeds in the same reactor by changing the reactants into regenerating reagent. After the coke deposited on the catalyst surface is removed by the regenerating reagent, the reactor will be switched to reaction phase again. By this way, the reaction-regeneration cycle advances alternately and the process proceeds continuously. A pilot process based upon the above philosophy has been developed by UOP (U.S. Pat. No. 5,012,021). Because there is a time interval between reaction and regeneration phase, there should be 3 or more reactors for total process.
The situation of the continuously stirred batch reactor is the same as that of the fixed bed reactor. The fresh solid catalyst contacts the reactants in the reactor and reaction undergoes in it. When the activity of

REFERENCES:
patent: 5012021 (1991-04-01), Vora
patent: 5489732 (1996-02-01), Zhang et al.
patent: 5565090 (1996-10-01), Gosling et al.
Vora et al., Tenside Surfactant Detergent 28(4), 287-294 (1991).

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