RU2458103C1 - Catalyst carrier for reforming of gasoline fractions and method of its production - Google Patents

Abstract

FIELD: oil-and-gas production.

SUBSTANCE: proposed catalyst comprises crystalline aluminium silicate, aluminium gamma-oxide and amorphous aluminium at the following radio of components, wt % aluminium silicate - 1-10, amorphous aluminium - 1-10, aluminium gamma-oxide making the rest. Proposed method comprises making the carrier of said composition by mixing dry powders of aluminium hydroxide and crystalline aluminium silicate, peptisation of produced mix by water solution of citric acid with solution concentration of 1-10 wt %, granulation and thermal treatment of produced carrier at, at least, 630°C.

EFFECT: higher efficiency of reforming.

3 cl, 6 ex

Description

The invention relates to the refining industry and is intended for use in the manufacture of catalyst supports for the process of catalytic reforming of gasoline fractions.

The task of increasing the yield of target products during oil refining and increasing the depth of processing of raw materials is largely solved by increasing the efficiency of catalytic processes. An increase in the conversion and yield of target products, in particular high-octane hydrocarbons, is achieved by modifying the catalysts — chemical, structural, and textural, including in the preparation of carriers by improving the synthesis parameters and by introducing various active additives into their composition.

Well-known methods for the preparation of reforming catalyst supports include the so-called plasticization operation, during which an electrolyte solution or, in other words, peptization of the starting aluminum hydroxide of a pseudoboehmite structure or pseudoboehmite with additives is performed. Next, granulation is carried out, usually by screw extrusion; the formed granules are dried and then calcined at a temperature not lower than 350 ° C, usually at 500-600 ° C. The most commonly used reforming catalyst carrier composition is a one-component, high purity gamma-alumina system resulting from calcination of pseudoboehmite.

For the purpose of modification, oxides of light and transition metals, as well as additives of an acidic nature, which change the ratio of the contributions of target reactions to the total complex reforming process, are used as additives. Often, crystalline aluminosilicates — zeolites — are used as acid additives [RF patent No. 2044940, 2000; RF patent No. 2027506, 1995], however, due to the introduction of components with high acidity (zeolites of the ZSM-5 family and / or mordenite), the contribution of cleavage reactions usually increases, resulting in a sharp decrease in the yield of liquid catalysis (up to 79- 82%).

It is known to use additives of zeolites such as erionite, which contribute to the selective hydrocracking of linear paraffins, without affecting branched alkanes [RF patents No. 1438228, 1997; No. 1438059, 1996]. The composition of the carrier proposed in the cited patents is two-component: 10-50% erionite, 90-50% aluminum oxide (in terms of calcined substances). The carrier is prepared by mixing aluminum hydroxide and erionite (in hydrogen or ammonium form), followed by peptization with an aqueous solution of mineral acid (usually nitric acid) and heat treatment (drying and calcination).

The reforming process using raw materials with a high content of naphthenes while observing certain process parameters on the catalysts using the indicated carriers allows one to obtain a reformate with a high octane number and practically with a small loss in the yield of liquid catalysis, however, the activity and stability of the catalysts are still not high (in a pilot test respectively 70-72, 82-84 and 7-19 wt.%).

Known methods for the preparation of erionite-containing carriers and catalysts for the conversion of various oil fractions (not reforming) [US patents No. 4021332, 1977; No. 3925191, 1975; No. 4,987,109, 1992; No. 6066251, 2000], including the mixing of erionite or a similar zeolite and aluminum hydroxide in various ratios (from 5: 95 to 95: 5, respectively), peptization of the resulting mixture with a solution of mineral acid, heat treatment of the carrier, then applying an adsorption method of a hydrogenating component (usually - platinum) and final heat treatment of the catalyst. In this case, the carriers are two-component systems of two crystalline phases: gamma alumina and zeolite.

The use of these methods allows to obtain carriers and reforming catalysts based on them, which give the following indicators in a pilot test: activity (arenas content in the catalysis as a result of the experiment at 470 ° C) - 71-73%, selectivity (yield of catalysis C ₅ + with arenas content 75%) - 81-84%, stability (drop in activity when tested in harsh conditions) - 8-14%. The indicated level of efficiency of reforming catalysts is insufficient.

A known method of preparing a carrier and a catalyst for the conversion of gasoline fractions (straight-chain hydrocarbons) based on erionite, which consists in introducing gallium ions (gallosilicate) into the zeolite [US Patent No. 5064793, 1991], which allows to achieve high flavoring activity, however, in a test pilot test, the catalyst gives unacceptably low levels of activity and stability (respectively 65-68 and 9-14 wt.%).

Closest to the proposed is a carrier of a hydrocarbon conversion catalyst (reforming) and a method for its preparation [RF patent No. 1614253, 1987 - prototype], which describes the mixing of erionite and aluminum hydroxide in the form of powders or gels, peptization of the mixture with mineral acid, molding by extrusion, heat treatment media at a temperature of 500-550 ° C with further application of the active metal (platinum) and chlorine, the final heat treatment of the catalyst is drying and calcination, as well as souring before use / test. In this case, as in previous cases, the carrier is a two-component system consisting of crystalline gamma-alumina and crystalline zeolite eriopite and does not contain amorphous aluminosilicate. The method allows to obtain a strong and relatively effective reforming catalyst, however, the levels of activity, selectivity and stability (respectively 72-75%, 83-86% and 5-10%) are not high enough.

The problem to which the invention is directed, is to increase the octane number of the product of the conversion of petroleum gasoline fractions by reforming, increase their yield and increase stability by creating a method for preparing an efficient reforming catalyst carrier for application conditions on reforming plants operated on raw materials with a high content of naphthenes (35-50%) and allowing the process to be conducted at relatively low temperatures (in the range of 440-500 ° C) and at a high volumetric feed rate (4-20 h ^-1 ).

The problem is solved and the goal is achieved when using as a catalyst carrier for the process of catalytic reforming of gasoline fractions of a three-component composition, including crystalline alumina in gamma form, crystalline aluminosilicate (zeolite) and additionally amorphous aluminosilicate with the following content of these components, wt.%: Crystalline aluminosilicate 1-10, amorphous aluminosilicate 1-10, crystalline gamma-alumina else.

As zeolite can be used erionite, ferrierite or filipsite in the hydrogen or ammonium form.

Amorphous aluminosilicate is formed under the conditions of preparation of the carrier proposed by us at the stages of mixing and peptization, is located in the boundary regions in the form of films and is an aluminosilicate with a silicon oxide content of 1-10%, which has an amorphous structure according to X-ray phase analysis (XPA).

A carrier containing amorphous aluminosilicate is prepared by mixing fine dry powders of aluminum hydroxide and crystalline aluminosilicate, peptizing the mixture with a 1-10% aqueous solution of citric acid, granulating, followed by heat treatment of the formed granules at a temperature of at least 630 ° C.

Significant differences of the proposed method are to use as a peptizer an aqueous solution of citric acid with a concentration of 1-10 wt.% And the specified temperature of calcination of the formed granules of the carrier containing, after calcination, up to 10 wt.% Of amorphous aluminosilicate.

This result was unexpected: when using peptization of a mixture of aluminum hydroxide and zeolite of other acids (not citric acid), both mineral and simple organic, this effect is not observed. Judging by the data of chemical and electron microprobe analysis, the resulting films are aluminosilicate, which is the product of the interaction of citric acid with aluminum hydroxide and zeolite. After calcination at temperatures above 630 ° C, organic residues are removed from the composition of the carrier, however, the reaction product retains an amorphous structure. To obtain the mentioned films, thin initial powders of the components and citric acid are used as a peptizing agent, which is used in the form of an aqueous solution with a concentration of 1-10 wt.%.

To obtain a reforming catalyst with the proposed carrier is carried out:

- a mixture of dry powders of aluminum hydroxide pseudoboehmite structure and zeolite (erionite or ferrierite, or filipsite) in the H-form or NH ₄ form;

- peptization of the resulting mixture by treatment with an aqueous solution of organic citric acid with continuous mechanical stirring to obtain an intermediate containing formed amorphous aluminosilicate films;

- granulation of the obtained gel by extrusion through a thin matrix (2-2.5 mm);

- heat treatment of freshly formed extrudates - drying and calcination in dried air at a temperature of at least 630 ° C;

- applying to the surface of the carrier an aqueous solution of the compound of the active components - platinum (in the form of platinum chloride) and chlorine (in the form of hydrochloric acid);

- heat treatment of the catalyst - drying and calcination in a stream of air;

- sulphurization of the catalyst in the gas phase by feeding through a contact layer a mixture of hydrogen sulfide with hydrogen (in a known manner).

The catalyst is tested in the process of catalytic reforming of a straight-run hydrotreated wide gasoline fraction with a boiling range of 85-180 ° C and the following contents of the main hydrocarbon classes, wt.%: Aromatic 7.0-9.0, naphthenic 35-50, olefinic 0.2-0 , 3, 51-58 and paraffin with a low content of sulfur - less than 0,5 ppmw (mg / kg or ppm ^-1).

First, the specified raw materials are reformed in mild mode: at temperatures of 440, 460 and 480 ° C, respectively, 40-50, 20-25 and 20-25 hours at a pressure of 1.5 MPa, a bulk feed rate of 4-5 hours ^-1 and multiplicity the circulation of hydrogen-containing gas (HSG) 1500 Nl / l of raw materials per hour. The total mileage in soft mode is about 4 days.

Then they switch to the hard mode under the following conditions: the temperature is increased to 510 ° C, the pressure is reduced to 1.0 MPa, and the circulation rate of the WASH is reduced to 1000 nl / l of raw material. The experiment is carried out for 100 hours.

The activity of the catalyst is characterized by the content of aromatic hydrocarbons in the catalysis obtained at a temperature of 460 ° C, the selectivity is characterized by the yield of liquid stable catalysis with a content of arenes of 74 wt.%, And as a measure of stability take the drop in activity during the test in hard mode (from the 20th at the 100th hour). When using the catalyst on the proposed carrier, the activity is in wt.%: 73.6 76.6, selectivity 89 90.6, stability 3.8-5.0.

EXAMPLE No. 1

Take 122.7 g of pural pseudoboehmite powder brand Pural SB (manufactured by Sasol, Germany), characterized by an annealing loss at 850 ° C (SPP) of 25.0%, which is 92 in terms of Al ₂ O ₃ , 0 g. The particle size of the pseudoboehmite powder is 5-20 microns.

Also take 8.0 g of "cake" (wet washed from salts and pressed on the filter cake) erionite in the N-form (production of the company "Süd-Chemie", Germany). PPP "lozenges" of zeolite 50%, calcined substance 4.0 g. The particle size of the zeolite is 2-5 microns.

The powders are mixed in a Werner mixer with Z-shaped blades for 15 minutes, and then subjected to peptization-modification.

For this, 100 cm ^{3 of an} aqueous solution of citric acid with a concentration of 7% are gradually added to the powders.

After extrusion, the obtained granules are dried and calcined at 630 ° C in air. Get about 100 g of the carrier - a mixture of gamma-alumina with erionite (respectively 96 and 4 wt.%).

The carrier is brought into contact with 140 ml of an aqueous impregnating solution containing 0.945 g of H ₂ PtCl ₆ , 2.2 ml of glacial acetic acid and 0.7 g of Hcl (38%). The impregnation is carried out for 2 hours with stirring, with 1 hour without external heating (or with cooling to 5-10 ° C) and 1 hour with heating at 80-85 ° C. At the end of this operation, the excess solution is drained, the granules are dried in air to a state of flowability of the catalyst. Next, the catalyst is dried at a temperature of about 150 ° C in static conditions (in an oven) and calcined in a tubular reactor in dried air: heating rate of 25 ° C / h, temperature 500 ° C, air flow rate of 131.6 l / h, duration calcining for 3-4 hours.

The composition of the catalyst (in wt.% In terms of pa dry matter): 0.45 Pt; 3.0 SiO ₂ (4% erionite with silicate mod 6.0); 0.65 Cl; the rest is aluminum oxide. According to the XRD, the content of the amorphous aluminosilicate film (a.s.) is ~ 4 wt.%.

Before the test, the catalyst is reduced with hydrogen at a temperature of 450-500 ° C, a pressure of 1.0 MPa and a supply of dry pure (electrolytic) hydrogen of 66.6 l / h for 3-4 hours and grained at the same temperature, passing through the catalyst layers a mixture hydrogen with hydrogen sulfide based on the feed 0.15% S by weight of the sample.

Results of a pilot test test:

- activity - the content of aromatic hydrocarbons in the catalyst obtained from the experiment at a temperature of 460 ° C - 75.0 wt.%;

- selectivity - the yield of stable C ₅ + catalysis with an aromatic hydrocarbon content of 72 wt.% - 89.0 wt.%;

- stability - index of the decline in activity in hard mode - 4.0 wt.%

EXAMPLE No. 2

In general, the same as in example No. 1, but with slight deviations.

Take 128.07 g of Pural SB pseudoboehmite powder with a particle size of 20-50 μm and an SPP = 25.0%, which corresponds to 96 g of Al ₂ O ₃ .

1.94 g of “cakes” of erionite in the NH ₄ form are weighed, having the following parameters: SPP = 50%, particle size 1-5 microns. In terms of the calcined product, the sample of erionite contains 0.97 g.

The retention of erionite in a mixture with alumina (for calcined substances) is 1 wt.%

The concentration of citric acid - peptizer - 1%

The calcination temperature of the carrier - 650 ° C

The content in the catalyst: Pt - 0.35%, Cl - 0.6%, SiO ₂ - 5.77%, amorphous A. with. films - 1%

Test Results:

- activity - 73.5 wt.%

- selectivity - 89 wt.%

- stability - 5 wt.%

EXAMPLE No. 3

The media as a whole is prepared as described in example No. 1, but with the following exceptions.

Pural pseudoboehmite powder Pural SB-1 was used, having a particle size of 10-50 μm and an SPP at 850 ° C = 28%. Taken 133.3 g of powder, which in terms of oxide is 96.0 g. The concentration of citric acid solution is 10.0 wt.%

Erionite in this sample was replaced by ferrierite (SPP = 12%, particle size 2-25 μm) in the amount of 12.12 g or 10.27 g per calcined product; the zeolite content in the carrier of 10.0 wt.%

According to the analysis, the content of amorphous A. with. films - 10%.

Standard Test Results:

- activity - 74.5 wt.%

- selectivity - 90.5 wt.%

- stability - 3.8 wt.%

EXAMPLE No. 4

The same as in example No. 3, but instead of ferrerite, zeolite filipsite was taken (SPP = 12%). The remaining conditions and parameters, as well as quantitative indicators of the composition do not differ from the values in examples 3 and 1.

Test Results:

- activity - 74.2 wt.%

- selectivity - 89.8 wt.%

- stability - 4.3 wt.%

EXAMPLE No. 5

The same as in example No. 1, but taken powder of erionite in ammonium form (NH ₄ -E). The particle size of erionite is 2-10 microns, SPP = 14%. 4.65 g of zeolite powder or 4.0 g per calcined product were used to formulate the composition.

The catalyst contains 96% alumina and 4% eriopite or 3.0% silica. The content of amorphous and.with. phase turned out to be equal to 1%. The concentration of citric acid taken for peptization and modification was 8%. The calcination temperature of the carrier was slightly increased to 660 ° C.

Test Results:

- activity - 76.1 wt.%

- selectivity - 90.3 wt.%

- stability - 4.2 wt.%

EXAMPLE No. 6

Similar to examples No. 1 and 5, but Catapal A powder (PPP = 25%, particle size 50-80 microns) was taken as pseudoboehmite, and erionite was also used as a “cake” in ammonium form (PPP = 50%, particle size 5-20 microns).

The platinum content of 0.45%, the content of silicon oxide is 3.0%, the chlorine content of 0.8%, the content of amorphous film 5%.

Test Results:

- activity - 76.6 wt.%

- selectivity - 90.6 wt.%

- stability - 4.3 wt.%

Claims (3)

1. A catalyst carrier for reforming gasoline fractions, including crystalline aluminosilicate, gamma alumina, characterized in that it additionally contains amorphous aluminosilicate with the following components, wt.%:
crystalline aluminosilicate 1-10 amorphous aluminosilicate 1-10 gamma alumina rest 2. The reforming catalyst carrier according to claim 1, characterized in that the crystalline aluminosilicate is a zeolite from the number: erionite, philipsite or ferrierite in hydrogen (H-) or ammonium (NH ₄ -) form. 3. A method of preparing a catalyst carrier for reforming gasoline fractions according to claim 1 by mixing dry powders of aluminum hydroxide and crystalline aluminosilicate, peptization of the resulting mixture with an aqueous acid solution, granulation, followed by heat treatment of the molded carrier, characterized in that citric acid with a solution concentration is used for peptization 1-10 wt.%, And heat treatment of the molded carrier is carried out at a temperature not lower than 630 ° C.