Catalytic reforming catalyst activation

Details Catalytic reforming catalyst activation Catalytic reforming catalyst activation

1999-06-30

2001-09-25

Griffin, Steven P. (Department: 1754)

Catalyst, solid sorbent, or support therefor: product or process

Regenerating or rehabilitating catalyst or sorbent

Gas or vapor treating

C502S053000, C502S325000, C502S326000

Reexamination Certificate

active

06294492

ABSTRACT:

This invention relates to the regeneration and activation of reforming catalyst and the use of such activated catalyst in the reforming of hydrocarbons.
BACKGROUND OF THE INVENTION
Catalytic reforming, or hydroforming, is a well established industrial process employed by the petroleum industry for improving the octane quality of naphthas or straight run gasolines. In reforming, a multi-functional catalyst is employed which typically contains a metal hydrogenation-dehydrogenation (hydrogen transfer) component or components, substantially atomically dispersed upon the surface of a porous inorganic oxide support, notably alumina.
In recent years, platinum has been widely commercially used as the metallic hydrogen transfer component of reforming catalysts, and platinum-on-alumina catalysts have been commercially employed in refineries. Also, additional metallic components, such as rhenium, iridium, ruthenium, tin, palladium, germanium and the like, have been added to platinum as promoters to further improve the activity, selectivity, or both, of the basic platinum catalyst.
In a conventional reforming process, a series of reactors constitute the heart of the reforming unit. Each reforming reactor is generally provided with a fixed bed or beds of the catalyst which receive upflow or downflow feed. Each reactor is provided with a heater because the reactions which take place therein are endothermic. In a conventional reforming process, a naphtha feed with hydrogen or hydrogen recycle gas is passed through a preheat furnace, then downward through a reactor, and then in sequence through subsequent interstage heaters and reactors of the series. The product of the last reactor is separated into a liquid fraction and a vaporous effluent. The vaporous effluent, a gas rich in hydrogen, is used as hydrogen recycle gas in the reforming process.
During operation, the activity of the reforming catalyst gradually declines due to the build-up of coke, and the temperature of the process is gradually raised to compensate for the activity loss caused by the coke deposits. Eventually, economics dictate the necessity of regenerating the catalyst.
The initial phase of catalyst regeneration is accomplished by burning the coke off the catalyst under controlled conditions. Catalyst regeneration is then completed through a sequence of activation steps wherein the agglomerated metal hydrogenation-dehydrogenation components are atomically redispersed. Such activation generally is achieved by treating the catalyst with hydrogen to effect reduction of the platinum oxide, and such other oxides as may be present in the catalyst system, followed by a chloride treatment of the reduced catalyst system prior to placing it back into use.
In addition to the activation process required when working with a catalyst which has been subjected to regeneration by burning off coke from the catalyst, there is generally carried out an activation treatment of the initially charged catalyst to the reactor prior to the introduction of hydrocarbon feed to the system.
In both the activation of fresh catalyst as well as the activation of a regenerated catalyst there have been numerous efforts to achieve a catalyst system whereby the catalyst will have increased activity, provide a product having increased octane values and avoid the undesirable cracking of product.
It is an object of the present invention to provide a process for the regeneration and activation of a platinum reforming catalyst.
Another object of the invention is to provide an improved system for the activation of a platinum reforming catalyst whereby the catalyst activity is increased.
A still further object of this invention is to provide an improved process for the activation of a platinum reforming catalyst which, when the activated catalyst is used in the reforming of a reformer feed, the cracking of such feed to undesired byproducts is reduced.
Yet another object of this invention is to provide a process for the activation of a platinum reforming catalyst which, when the activated catalyst is used in the reforming of a reformer feed, the cracking of such feed is decreased while the octane number of the reformer product is increased.
Other aspects, objects and the several advantages of the invention will be apparent from the following specification and appended claims.
SUMMARY OF THE INVENTION
In accordance with the present invention, an improved reforming catalyst is obtained when the catalyst, during reduction with hydrogen, is simultaneously contacted with hydrogen and a nonmetallic chlorine-containing compound in a reactor of a series of multiple reactors, and thereafter a hydrogen purge is maintained for a sufficient amount of time to expose the reforming catalyst to about 100 to about 50,000 cubic feet of hydrogen per cubic foot of catalyst prior to bringing the system to reforming conditions.
Thus, in accordance with one aspect of the present invention, there is provided a process for the activation of a platinum reforming catalyst contained in a multiple reaction zone system, said process comprises: (a) reducing the catalyst with hydrogen; (b) simultaneously with step (a) contacting the catalyst with a nonmetallic chlorine-containing compound by introducing the nonmetallic chlorine-containing compound into a reaction zone of the multiple reaction zone system under conditions to effect decomposition of the nonmetallic chlorine-containing compound; and (c) thereafter purging the resulting chlorine-treated catalyst with hydrogen for a period of time necessary to remove excess chlorine from the catalyst prior to the use of said chlorine-treated catalyst in a reforming process.
In accordance with another aspect of the present invention, there is provided an improved process for the regeneration of a platinum reforming catalyst contained in a multiple reaction zone system, said process comprises: (a) purging the multiple reaction zone system with nitrogen; (b) subjecting the deactivated catalyst to an oxidative burning off at a temperature and for a time sufficient to remove substantially all carbonaceous deposits thereon; (c) subjecting the substantially-carbon-free catalyst to an oxygen treatment for a period of time sufficient to effect the oxidation of metals contained in the substantially-carbon-free catalyst; (d) purging the resulting oxidized catalyst of molecular oxygen; (e) cooling the resulting purged catalyst; (f) reducing the cooled catalyst by contacting with hydrogen which is introduced into a reaction zone of the multiple reaction zone system; (g) simultaneously with step (f) contacting the catalyst with a nonmetallic chlorine-containing compound by introducing the chlorine-containing compound into a reactor of the multiple reaction zone system; and (h) thereafter purging the resulting catalyst systems of steps (f) and (g) with hydrogen for a period of time necessary to remove excess chlorine from the catalyst prior to start up of the multiple reaction zone reforming system.


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“Catalytic Reforming Process Technology” by Refining Process Services, Inc., Cheswick, PA, Title Pages and pp. 6,15-16, and 19 of section 3, dated Jul. 18, 2000.

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