Olefin upgrading process with guard bed regeneration

Abstract

A process for the regeneration of materials used in the guard beds preceding the reactors used in an olefin conversion process which converts olefinic refinery streams to higher boiling hydrocarbon products by polymerization (oligomerization) or alkylation of aromatics including benzene. Products of the process may include olefin oligomers and alkylaromatics in the gasoline boiling range as well as alkylaromatic petrochemicals such as cumene and ethylbenzene. The process is integrated with the olefin conversion process to ensure continuous operation of the olefin conversion without sending the feedstock containing the contaminant(s) to the reactor. The process uses reaction products from the olefin conversion process to regenerate the guard bed material and so is economically attractive since it does not require the use of separate purge, regeneration feed and separation systems. A plurality of guard beds is used, each containing a material which removes catalyst poisons. The guard beds are operated on a swing system in which one or more beds is kept on stream to remove the contaminant(s) while one or more of the remaining beds is being purged or regenerated. In this way, continuity of operation is assured. The regeneration medium is a product stream from the olefin conversion process.

Description

CROSS REFERENCE TO RELATED APPLICATIONS[0001]This application claims priority from U.S. Provisional Patent Application Ser. No. 60 / 834,804, filed 2 Aug. 2006.FIELD OF THE INVENTION[0002]This invention relates to a method for the regeneration of guard bed sorbents and catalysts used in light olefin polymerization and alkylation processes for the production of gasoline boiling range motor fuel.[0003]The present application is related to the following previously filed applications which describe related catalytic processes used for making gasoline boiling range liquid hydrocarbon products:U.S. Ser. No. 11 / 362,257, filed 27 Feb. 2006, “Gasoline Production by Olefin Polymerization”.U.S. Ser. No. 11 / 362,128, filed 27 Feb. 2006, “Gasoline Production By Olefin Polymerization With Aromatics Alkylation”U.S. Ser. No. 11 / 362,256, filed 27 Feb. 2006, “Process for Making High Octane Gasoline with Reduced Benzene Content”U.S. Ser. No. 11 / 362,255, filed 27 Feb. 2006, “Vapor Phase Aromatics Alkylati...

AI Technical Summary

Benefits of technology

[0014]According to the present invention, an olefin conversion process which converts olefinic refinery streams to other, higher boiling hydrocarbon products by polymerization (oligomerization) or aromatics alkylation over a molecular sieve catalyst utilizes a plurality of guard beds containing a material which removes catalyst poisons. The guard beds are operated on a swing system in which one or more beds is kept on stream to remove the contaminant(s) while one or more of the remaining beds is being purged or regenerated. In this way, continuity of operation is assured. The regeneration medium is a product stream from the olefin conversion process.

Problems solved by technology

While these olefins may be used as petrochemical feedstock, many conventional petroleum refineries producing petroleum fuels and lubricants are not capable of diverting these materials to petrochemical uses.

In the SPA polymerization process, feeds are pretreated to remove hydrogen sulfide and mercaptans which would otherwise enter the product and be unacceptable, both from the view point of the effect on octane and upon the ability of the product to conform to environmental regulations.

Conversely, if the feed is too dry, coke tends to deposit on the catalyst, reducing its activity and increasing the pressure drop across the reactor.

Limited amounts of butadiene may be permissible although this diolefin is undesirable because of its tendency to produce higher molecular weight polymers and to accelerate deposition of coke on the catalyst.

In spite of the advantages of the SPA polymerization process, which have resulted in over 200 units being built since 1935 for the production of gasoline fuel, a number of disadvantages are encountered, mainly from the nature of the catalyst.

Although the catalyst is non-corrosive, so that much of the equipment may be made of carbon steel, it does lead it to a number of drawbacks in operation.

First, the catalyst life is relatively short as a result of pellet disintegration which causes an increase in the reactor pressure drop.

Second, the spent catalyst encounters difficulties in handling from the environmental point of view, being acidic in nature.

Third, operational and quality constraints limit flexible feedstock utilization.

Conventionally, a single guard bed is used, making it necessary either to cease operation during regeneration or to send the feed directly to the reactor without separation of the contaminant(s), so shortening catalyst life commensurately.

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