Chevron Research Company

Waldeen C Buss

Thomas R Hughes

Leslie Ann Field

Charles R Wilson

Harris E Kluksdahl

Richard C Robinson

Sue D Pandey

A new catalyst is disclosed which is useful for dehydrocyclizing alkanes. This catalyst contains a type L zeolite, a Group VIII metal, and an alkaline earth metal. Preferably, this catalyst contains a type L zeolite, from 0.1% to 5% by weight platinum and from 1% to 20% by weight barium.

Platinum-barium-type L zeolite

A new catalyst is disclosed which is useful for dehydrocyclizing alkanes. This catalyst contains a zeolite of the L family, a Group VIII metal, and an alkaline earth metal.

Platinum-barium-zeolite of L family

A reforming catalyst comprising a large-pore zeolite and at least one reforming catalytic metal selected from the group consisting of the Group VIII noble metals, having enhanced sulfur tolerance achieved by adding at least one desulfurization metal to the catalyst; and a reforming process having high selectivity for dehydrocyclization which comprises contacting a naphtha boiling in the gasoline boiling range and containing some acyclic hydrocarbons with the foregoing catalyst.

Sulfur tolerance of zeolitic reforming catalysts

A method of dehydrocyclizing alkanes is disclosed wherein the alkanes are contacted with a catalyst containing a large-pore zeolite, a Group VIII metal, and an alkaline earth metal wherein the Selectivity Index is greater than 60%.

Catalyst for dehydrocyclizing alkanes

A reforming process is disclosed wherein a hydrocarbon feed is contacted with two reforming catalysts at conditions which favor reforming. The first reforming catalyst comprises a metallic oxide support having disposed therein a Group VIII metal. This first reforming catalyst may contain Group VIII metal promoters, such as rhenium, tin, germanium, cobalt, nickel, iridium, rhodium, ruthenium and combinations thereof. The second reforming catalyst is a non-acidic catalyst comprising a large-pore zeolite containing at least one Group VIII metal. A preferred first reforming catalyst comprises alumina having disposed therein in intimate admixture platinum and rhenium. A preferred second reforming catalyst is a non-acidic catalyst comprising a type L zeolite containing platinum.

Reforming process

Reforming with a platinum-barium-zeolite of L family

A hydrocarbon conversion process is disclosed wherein the alkanes are contacted with a catalyst containing a metallic oxide support and a Group VIII metal, and with a catalyst containing a large-pore zeolite, a Group VIII metal, and an alkaline earth metal.

Method of dehydrocyclizing alkanes

A method of preparing a reforming catalyst is disclosed wherein a large-pore zeolite is impregnated with an aqueous solution of platinum and the zeolite is only allowed to soak in the solution for less than three hours to form a catalyst. After the catalyst is dried, it is calcined in an atmosphere containing steam.

Preparation of a reforming catalyst

A pretreatment method is disclosed for enhancing the selectivity and increasing the stability of a reforming catalyst comprising a large-pore zeolite containing at least one Group VIII metal. In this method, the catalyst is reduced in reducing atmosphere at a temperature of from 250.degree. C. to 650.degree. C., exposed to an oxygen-containing gas, treated in a reducing atmosphere at from 120.degree. C. to 260.degree. C., and maintained at a temperature of from 370.degree. C. to 600.degree. C. in a reducing atmosphere.

Pretreatment method for enhancing the selectivity and increasing the

A new catalyst is disclosed which is useful for dehydrocyclizing alkanes. This catalyst contains a type L zeolite, a Group VIII metal, and an alkaline earth metal. This catalyst has been reduced in a hydrogen atmosphere at a temperature of from 480.degree. C. to 620.degree. C.

Composition and a method for its use in dehydrocyclization of alkanes

The process of oxidatively regenerating in situ a fixed bed hydrocarbon catalyst which is sensitive to reactive sulfur compounds in a conversion system having sulfur-contaminated vessels and/or conduits in the flow path upstream from said catalyst is improved by passing regenerating oxygen-containing gas first through the sulfur-contaminated vessels and/or conduits and then through the fixed catalyst bed while limiting the water content of the regenerating gas to a concentration of not more than 0.1 mol percent throughout the flow path and at a temperature in the range of 750.degree.-1100.degree. F. to oxidize the sulfur contaminants in the vessels and/or conduits upstream from the catalyst. Thereby the evolved sulfur oxides flow through the fixed bed catalyst in the absence of sufficient water which would promote reaction of sulfur oxides with the catalyst. The low water content regenerating gas is continued until substantially all the oxidizable sulfur contaminants are removed from the vessels and/or conduits. Thereafter, carbonaceous deposits are oxidized from the catalyst.

Semi-continuous regeneration of sulfur-contaminated catalytic conversion

A method is disclosed for regenerating reforming catalysts containing a platinum group component and/or rhenium component in association with a halogen component on a porous inorganic oxide, such as one containing alumina without significant displacement of the rhenium components by sulfur oxides generated during the regeneration process. The method is particularly characterized in that carbon is removed from the catalyst by in situ oxidation at temperatures not in excess of about 750.degree. F. and without modification of the catalytic reforming process flow circuit, as by disconnecting or isolating the heat exchangers and furnace tubes. Sulfide scale is converted in a separate oxidation step to sulfur dioxide, SO.sub.2, without substantial oxidation to sulfur trioxide, SO.sub.3, by maintaining the inner walls of the heat exchangers and furnace tubes, where such iron sulfides are present, at a temperature not in excess of about 900.degree. F. and not less than about 750.degree. F. and under regenerating conditions including a low oxygen, O.sub.2, concentration. The sulfur dioxide then passes through the reforming catalyst without effectively displacing rhenium components from the carrier base. Further, by removal of these sulfides, complete regeneration of the catalyst is facilitated for subsequent redistribution of the platinum component at temperatures in excess of 900.degree. F., particularly when accompanied by halide addition.

In situ hydrocarbon conversion catalyst regeneration and sulfur

A hydrocarbon conversion process is disclosed having a very high selectivity for dehydrocyclization. In one aspect of this process, a hydrocarbon feed is subjected to hydrotreating, then the hydrocarbon feed is passed through a sulfur removal system which reduces the sulfur concentration of the hydrocarbon feed to below 500 ppb, and then the hydrocarbon feed is reformed over a dehydrocyclization catalyst comprising a large pore zeolite containing at least one Group VIII metal to produce aromatics and hydrogen.

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Kensington, CA, United States of America

Waldeen C Buss