RU2471855C1 - Catalytic reforming method of gasoline fractions - Google Patents

Abstract

FIELD: oil and gas industry.

SUBSTANCE: invention refers to catalytic reforming method of gasoline fractions at increased temperature and pressure in presence of platinum erionite containing catalysts, which is implemented in block consisting of five in-series located reactors, in the first one of which (forcontactor) there performed is preliminary dehydration of cyclohexane hydrocarbons contained in raw material, in presence of halogen-containing platinum catalyst, and in the next reactors (from the second one to the fifth one) there performed is reforming process with subsequent increase in erionite content in modifications of catalysts in the direction of the supplied raw material. Reforming process is performed in presence of catalysts with the following content of erionite in them as to reactors: to the second (in the direction of raw material) and the third reactors there loaded are catalysts with erionite content in each of them, which is equal to 0.5-3.0 wt %, and the fourth and the fifth reactors - with erionite content of 2.5-3.7 wt %; at that, to forcontactor there loaded is platinum catalyst containing mixture of fluorine and chlorine as haloid.

EFFECT: improvement of reforming process properties - activity, selectivity and stability.

1 tbl, 2 ex

Description

The invention relates to the field of catalytic reforming and can be used in oil refining, petrochemical and gas industries in the process of reforming gasoline fractions using various catalytic compositions.

The task of increasing the efficiency of processing, in particular the octane number and the yield of target products, is primarily solved by increasing the efficiency of catalytic processes, which include catalytic reforming. The increase in the octane number of the product is achieved both by modifying the catalysts, including introducing zeolites into their composition, and by optimizing the composition and location of catalysts of different compositions in different reactors.

Often used is the technique of modifying catalysts by introducing various additives of an acidic nature. As acidic additives, crystalline aluminosilicates — zeolites — are also used [RF patent No. 2144940, 2000; RF patent No. 2027506, 1995]. This changes the ratio of the contributions of the main and secondary reforming reactions; however, as a result of introducing components with high acidity into the catalysts (zeolites of the ZSM-5 type, mordenite and other highly acidic zeolites), the contribution of cleavage reactions usually increases, as a result of which the yield of liquid catalysis decreases (sometimes - up to 79-82% wt.).

It is known to use catalysts with the addition of erionite, which promotes the selective hydrocracking of linear paraffins without affecting branched alkanes [RF patents No. 1438228, 1997; No. 1438059, 1996]. In these patents, the catalyst contains (in terms of calcined substance) 10-50% wt. erionite, as well as platinum, chlorine and, possibly, promoters, the rest is gamma-alumina. These patents do not provide for loading catalysts of different compositions into various reactors of a catalytic reforming unit.

The reforming unit of the UKR KOMT installation of the Surgut gas condensate stabilization plant (GSC) includes five reactors of the same volume connected in series [Ishmurzin A.V., Minkhairov M.F., Pershin V.A. et al. Gasoline reforming on an alumina-platinoerionite catalyst. - J. “Oil Refining and Petrochemistry”. - 2007. - No. 12. - p.10-12]. Until now, during operation, the same catalysts or catalysts of similar composition were loaded into all the reactors of this installation: in the first working cycle, SG-3P platinum catalysts containing 20-30% wt. erionite mixed with gamma alumina [A.S. USSR No. 1438059, 1987]. In the course of operation, one of the reactors was put into the precontactor operation mode, namely, it was used as a reactor for the conversion (dehydrogenation) of naphthenes, which basically came down to using it at a low temperature

In the second cycle, a combination of the platinum catalysts SG-3P-M, brands A and B, containing different amounts of erionite — 3.75–5 and 7.5–10 wt%, respectively, was loaded into the reactors of the reforming unit of the UKR KOMT installation. Moreover, a catalyst with a lower zeolite content (grade “A”) was loaded into the first three reactors, counting along the feed, i.e. into the contactor and the first two working reactors. The catalyst with a higher erionite content (SG-3P-M, grade “B”) was loaded into two “tail” reactors (the last, 4th and 5th along the feed). Thus, platinum erionite-containing catalysts with a zeolite content of 3.75 to 10 wt% were placed in all reactors.

When working on the first loading of SG-3P catalysts (first duty cycle), the following results were achieved: the activity, expressed as the octane number of stable catalysis, was 82-83.5 pp (Urine), selectivity or yield of stable catalyzate - 83-86% wt.

At the second combined loading of the SG-3P-M catalysts, the following operation results were obtained: activity - 83.5-85 pp (Urine), selectivity - 87-90% wt.

Closest to the proposed is a method of catalytic reforming using a combination of erionite catalysts - SG-3P-M grade A and SG-3P, containing from 4 to 15% wt. erionitis [RF patent No. 2352612, 2007].

This method suggests carrying out the process at elevated temperature and pressure using two grades of platinum erionite-containing catalysts: SG-3P-M grade A with a content above 3.75% wt. erionite and SG-3P with a content of 10% wt. erionitis and more. At the same time, it is proposed to load grade A SG-3P-M catalyst into the first three (out of five) reactors, and the SG-3P catalyst into the other two. In the first reactor, naphthenes are dehydrogenated at a temperature of 410 ° C and a volumetric feed rate of 20 h ^-1 , in the subsequent ones, the reforming process is carried out directly at a temperature at the inlet of each reactor at 490 ° C, a pressure of 2.0 MPa, a VSH circulation rate of 1200 nm ³ / m ³ and a volumetric feed rate of 5 h ^-1 .

The disadvantage of this process is the use of catalysts with an excessively high erionite content, as well as the use of a zeolite-containing catalyst in the fore contactor, which leads to a slightly reduced process activity. The activity of the process using this method does not exceed IOI 85 p.p.

The present invention solves the problem of increasing the octane number of the product from 94-95 pp (IOI) up to 96.0-96.2 p.p. while maintaining high selectivity (stable catalyst yield).

The task in this invention is achieved through the use of a combination of platinum catalysts with a low content of erionite (not more than 3.7% wt.); the erionite content increases in the reactors along the feedstock, and the catalyst in the precontactor does not contain zeolite, and fluorine (0.35% wt.) and chlorine (~ 0.30-0.35% wt.) as a halogen in the first and second working reactors contain a small amount of erionite (0.5-3% wt.), and two tail reactors (fourth and fifth along the feed) contain a platinum erionite catalyst with a zeolite content of from 2.5 to 3.7% wt.

The difference of the proposed method from the known one (prototype) consists in the use of a combination of catalysts, which includes loading into the precontactor a platinum-free erionite catalyst on a carrier consisting of gamma-alumina with fluorine and chlorine additives, and in working reactors - platinum erionite-containing catalysts, and in the second and the third reactors in the course of raw materials are loaded with catalysts with an erionite content of 0.5-3.0% wt., and in the fourth and fifth - catalysts with an erionite content of 2.5-3.7% wt.

The proposed catalysts with the indicated erionite content are prepared in a known manner by mixing pseudoboehmite and erionite powders in a predetermined ratio, peptizing them with acid, then granulating by screw extrusion or droplet molding, drying and calcining the carrier, followed by the adsorption method of platinum and chlorine and heat treatment of the catalyst [US patents No. 4021332, 1977; No. 3925191, 1975; No. 4,987,109, 1992; No. 6066251, 2000],

Raw materials - straight-run wide gasoline fraction boiling in the range from 85 to 180 ° C - are fed into a system of five reactors. In the first of them (fore contactor), dehydrogenation of cyclohexane hydrocarbons is carried out at a temperature of 410 ° C, a feed volumetric feed rate of 20 h ^-1 , a pressure of 2.0 MPa, a VSH circulation rate of 1200 nm ³ / m ³ . In subsequent (working) reactors, the reforming process itself is carried out under the following conditions: temperature at the inlet of the reactor is 490 ° С, the volumetric feed rate is 5 h ^-1 , pressure is 2.0 MPa, the circulation rate of the VSG is 1200 nm ³ / m ³ .

The product is characterized by the octane number according to the research method, in short - IOI (activity), and the yield on raw materials (selectivity). The process using the proposed combination of catalysts allows to achieve an octane number (IOI) of more than 96 pp (96.0-96.2) with a selectivity of more than 89% wt. (from 89.6 to 91).

The industrial applicability of the invention is illustrated by the following examples and table.

EXAMPLE No. 1

A ball or extruded catalyst of the composition is loaded into the precontactor: 0.45% Pt, 0.35% F, 0.5% Cl, the rest is gamma-alumina.

The catalyst in the form of balls or cylindrical extrudates containing 0.40% Pt, 2.875% erionite, the rest is chlorinated alumina, is loaded into the second reactor along the feedstock (the first working one). A catalyst with 0.40% platinum and 2.875% erionite is loaded into the third reactor, a catalyst with 3.7% erionite and 0.4% Pt in the 4th reactor, and a catalyst with 3.7% erionite and 0 in the 5th reactor , 4% Pt (the rest is gamma alumina + chlorine). Hereinafter: all catalysts can be either spherical in the form of granules, or cylindrical (extrudates), or any mixture thereof.

The obtained reformate has an IOC of 96.2 p., The yield of raw materials was 89.6%.

EXAMPLE No. 2.

As in the first example, a fluorine-containing catalyst is loaded into the precontactor, but with 0.45% Pt and 0.55% Cl.

A catalyst containing 0.45% Pt, 1.0% erionite, the rest is chlorinated alumina, is loaded into the second reactor along the feed. A catalyst with 0.35% platinum and 2% erionite is loaded into the third reactor, a catalyst with 2.5% erionite and 0.4% Pt in the 4th reactor, and a catalyst with 3.7% erionite and 0 in the 5th reactor , 4% Pt (the rest is gamma alumina + chlorine). The product is a reformate with an IOC of 96.0 p., And the yield of liquid catalyzate by feed was 90.4%.

Table The distribution of catalysts for working reactors and the results obtained Example No. The content of erionite (%) in the catalyst loaded in the reactor No. Application Results one 2 3 four 5 IOCH, p.p. Exit, % one 0 2,875 2,875 3.70 3.70 96.2 89.6 2 0 1,0 2 2,5 3,7 96.0 90,4

Claims (1)

The method of catalytic reforming of gasoline fractions at elevated temperature and pressure in the presence of platinum erionite-containing catalysts, carried out in a block of five successive reactors, in the first of which (precontactor), preliminary dehydrogenation of cyclohexane hydrocarbons in the feed in the presence of a halogen-containing platinum catalyst is carried out, and in subsequent second to fifth reactors carry out a reforming process with a gradual increase in the content of erionite in mo catalysts along the feed, characterized in that the reforming process is carried out in the presence of catalysts with the following erionite content in the reactors: in the second (along the feed) and third reactors load catalysts with an erionite content of 0.5 in each of them -3.0 wt.%, And in the fourth and fifth reactors with an erionite content of 2.5-3.7 wt.%, While a platinum catalyst containing a mixture of fluorine and chlorine as a halogen is loaded into the fore contactor.