RU2728554C1 - Apparatus for treating zeolite by ion exchange and method of producing catalyst using said device - Google Patents

Abstract

FIELD: chemistry.SUBSTANCE: invention relates to production of zeolite catalysts and can be used in catalysis, particularly catalysis of isobutane alkylation processes with butylenes. Disclosed is an apparatus for treating zeolite by ion exchange, comprising an autoclave made in the form of a cylindrical housing filled with a reaction medium and equipped with a sealed cover, and placed in a detachable heating jacket. Housing of autoclave is additionally equipped with teflon sleeve-insert tightly adjacent to its walls. Housing is fixed in stationary rack with possibility of its inclination angle adjustment during autoclave installation at angle of 30–60 °C. At the base of the post there is a motor connected on one side to the setter of rotation frequency of the housing, and on the other side - to a rotary mechanism providing rotation of the housing at a rate of up to 3.0 rpm inside a stationary heating jacket coaxial to it, which is rigidly connected to the post. Autoclave cover is equipped with pocket for thermocouple, which is installed in reaction medium, and manometer. Also disclosed is a method of producing an alkylation catalyst of isobutane with butylene via successive ion exchange of NaX type zeolite on calcium, lanthanum and ammonium, drying and calcination. Ion exchange is carried out in hydrothermal conditions in a medium of aqueous solutions of salts of said cations in said device during installation of autoclave at angle of 30–60° at temperature 150–180 °C for the time required to convert the initial zeolite into a form which is substituted with calcium, lanthanum and ammonium with NaO content in the final catalyst of less than 1 wt. %.EFFECT: device and method provide high-quality ion exchange to obtain a catalyst without destroying catalyst granules and, as a result, high catalyst activity on conversion of olefins, yield of alkylate, selectivity to trimethylpentanes.2 cl, 1 dwg, 1 tbl, 9 ex

Description

The invention relates to the field of obtaining zeolite catalysts and can be used in catalysis, in particular, catalysis of isobutane alkylation processes with butylenes.

A known method of producing a catalyst for the alkylation of isobutane with olefins, including butylenes (see USSR AS No. 1309383 A1, class IPC B01J 29/12, C07B 37/00, publ. 20.10.1996). To obtain a catalyst, powdered zeolite of the faujasite type is loaded into an autoclave and poured with a solution of calcium chloride, after holding at a temperature of 140-200 ° C, ion exchange with nitrates of rare earth elements is carried out in the same way. The resulting rare earth calcium zeolite is cooled, washed, dried and tableted. The tablets (granules) are poured with a mixture of palladium tetraammoniumate and ammonium nitrate, kept at room temperature until the palladium is evenly distributed over the granule volume. The solution is decanted, the granules are washed, dried and calcined. The resulting catalyst was tested in the alkylation of isobutane with butylenes at an isobutane: butylenes ratio of 27: 1 at a temperature of 90 ° C, a space velocity of 1.2 h for 7 h.

The disadvantage of the known method and device is that in a stationary autoclave there is no mixing of the reaction medium, ion exchange does not take place in the entire volume of the autoclave, and the resulting catalyst contains a significant amount of the phase that has not undergone ion exchange, which leads to a decrease in the catalytic activity of the prepared alkylation catalyst ...

Closest to the proposed device is a method for producing a catalyst for the alkylation of isobutane with olefins based on zeolite (see RF patent No. 2445164 C1, class IPC B01J 29/12, B01J 29/14, B01J 29/16, B01J 23/02, B01J 23 / 10, B01J 37/02, С07В 37/00, publ. 03/20/2012), including its treatment with aqueous solutions of calcium salts, rare earth elements and ammonium at elevated temperature and saturated vapor pressure, followed by the application of active metals by impregnation with aqueous solutions of salts of active metals , then washing, drying, tableting, since powdered zeolite of the faujasite type is used, and calcining. The treatment with aqueous solutions is carried out in a stationary autoclave without stirring while heating the autoclave to 160-200 ° C.

The disadvantage of this method is the low selectivity of the catalyst in the amount of isoC8 (the best result is 73.5 wt%, with a conversion of 100 wt% and a product yield of 204 wt%) in the reaction product (alkylate), which may be caused by an incomplete exchange from - due to the lack of mixing of the solution and zeolite powder.

The objective of the invention is the development of a device and a method that provide high-quality ion exchange to obtain a catalyst without destroying the catalyst granules and an increase in the activity of the catalyst for the conversion of olefins, the yield of alkylate, selectivity for trimethylpentanes.

The problem is solved by the fact that in a device for processing zeolite by ion exchange, including an autoclave made in the form of a cylindrical body filled with a reaction medium and equipped with a sealed lid and placed in a split heating jacket, the autoclave body is additionally equipped with a Teflon cup tightly fitting to its walls - with an insert, the body is fixed in a stationary rack with the possibility of adjusting its angle of inclination when installing the autoclave at an angle of 30 ÷ 60 degrees, at the base of the rack there is an engine connected on one side with the body rotation frequency regulator, and on the other - with a rotary mechanism providing rotation housing with a speed of up to 3 rpm inside a stationary heating casing coaxial to it, which is rigidly connected to the rack, the autoclave lid is equipped with a pocket for a thermocouple, which is installed in the reaction medium and a manometer.

The principle of operation of the device is that the latter controls the mode of the ion exchange process of the catalyst for the alkylation of isobutane with butylenes, namely, the precise determination of the conditions under which the exchange is carried out, pressure and temperature, which contributes to a quick response in the event of a violation of the synthesis mode.

The problem is also solved by the fact that in the method of obtaining a catalyst for the alkylation of isobutane with butylenes by sequential ion exchange of NaX type zeolite for calcium, lanthanum and ammonium, drying and calcination, ion exchange is carried out under hydrothermal conditions in the medium of aqueous solutions of salts of the indicated cations in the claimed device during installation autoclave at an angle of 30 ÷ 60 ° at a temperature of 150-180 ° C for the time required to convert the original zeolite into a form substituted with calcium, lanthanum and ammonium when the Na ₂ O content in the final catalyst is less than 1 wt. %.

The salts used are nitrates of calcium, ammonium and rare earth elements, in particular lanthanum.

As starting zeolites, granular and compressed zeolites without a binder or molded with a binder, for example, with clay or aluminum hydroxide, can be used.

The proposed device is shown in FIG. 1 and consists of:

1 - cylindrical body;

2 - a sealed cover;

3 - manometer;

4 - thermocouple pockets;

5 - teflon liner;

6 - heating jacket;

7 - stationary rack;

8 - engine;

9 - housing rotation frequency setting;

10 - rotary mechanism;

11 - casing heating control systems. The proposed device works as follows.

A teflon liner (5) is installed in a cylindrical body (1) with a sealed cover (2) equipped with a manometer (3) and a thermocouple pocket (4) for measuring the temperature inside the autoclave. Zeolite is poured into a Teflon insert (5), which is poured with a prepared salt solution, and the total volume of salt and zeolite should not exceed 2/3 of the volume of the insert. The concentration of the solution and the mass of the salt are calculated on the absolutely dry matter of the taken zeolite. Moreover, the mass ratio of the salt solution to the mass of the taken zeolite is taken from the range (2 ÷ 10): 1, preferably 8: 1. Ion exchange is carried out sequentially with solutions of salts of calcium nitrate, lanthanum and ammonium or with combining exchanges, for example, combining ion exchanges for lanthanum and ammonium.

Moreover, the cylindrical body (1) is placed in a split heating casing (6), equipped with a thermocouple for measuring the heating temperature, and fixed on a stationary rack (7), which allows you to adjust the angle of inclination of the cylindrical autoclave body. The angle of inclination of the cylindrical body of the autoclave depends on the amount of zeolite loaded for exchange, but it is necessary to use the angle of inclination of the cylindrical body of the autoclave from 30 to 60 °.

On a stationary rack (7), a motor (8) is installed, which ensures the rotation of the autoclave with a predetermined number of revolutions due to the specified number of revolutions on the rotational speed generator (9), through a rotary mechanism (10) connecting the motor to the bottom of the cylindrical body of the autoclave. The number of revolutions varies up to 3 revolutions per minute, preferably 1 revolution per minute.

Heating of a cylindrical autoclave is carried out by means of a heating control system (11), which is equipped with devices necessary to regulate and maintain a predetermined ion exchange temperature.

At the end of the ion exchange, the cylindrical body (1) is cooled, and the heating is stopped using the autoclave heating control system (11). After cooling the autoclave to a temperature of 30-60 ° C, the rotation of the latter is stopped with the help of the rotary dial (9), the sealed cover (2) is removed and the Teflon liner (5) is removed.

The mother liquor is drained from the Teflon liner beaker (5), separating it from the treated zeolite. The zeolite is washed with demineralized water, dried and ignited.

The completeness of the ion exchange is assessed by the elemental analysis of the treated zeolite, for example, by X-ray fluorescence analysis.

Preferably, the alkylation of isobutane with butylenes is carried out at a temperature of 60 ÷ 95 ° C, a pressure of 0.85 ÷ 1.8 MPa, a volumetric feed rate for butylenes 0.2 ÷ 0.6 h ^-1 , the ratio of isobutane: butylenes in the feed is 5 ÷ 27: 1, and the duration of the feedstock supply is 4--36 h.

The alkylation process is carried out in accordance with the description (see RF patent No. 188626 U1, class IPC С07С 2/58, С07С 9/00, publ. 18.04.2019), according to the above formulas, the main indicators of the alkylation process of isobutane with butylenes are calculated:

- conversion of butylenes - the ratio of the amount of converted raw materials to taken, characterizes the completeness of the use of raw materials and is expressed in wt. %,

- the yield of alkylbenzene from butylenes in the feed; - the yield of the reaction product (alkylate) based on the used butylenes contained in the feed, and is expressed in wt. %,

- the selectivity of the reaction - the relative concentration of the isooctane fraction, the most valuable component of gasoline, on the reaction products and is expressed in wt. %.

Catalyst productivity, removal of alkylate from 1 gram. catalyst (weight of alkylate per weight of catalyst per hour) is calculated by the formulas given in the description (see RF patent No. 2672063 C1, class IPC B01J 37/30, B01J 29/08, publ. 09.11.2018).

The technical result that can be obtained from the proposed invention is as follows:

- high-quality ion exchange to obtain a catalyst without destroying the granules;

- an increase in the activity of the catalyst for the conversion of butylenes, practically up to 100 wt. %;

- an increase in the activity of the catalyst for the yield of alkylate;

- increased selectivity for trimethylpentanes, the main products of the process;

- increasing the productivity of the catalyst. The following examples illustrate the proposed technical solution, but in no way limit it.

Example 1

A catalyst sample is prepared on the basis of powdered NaX type zeolite. Ion exchange of zeolite (30 g) for calcium is carried out in a solution of calcium nitrate (solution concentration 82 g / l, amount 240 ml) in an insert glass, which is installed in an autoclave with an inclination angle of 45 °, the rotation speed of the autoclave is 1 rpm, at a temperature 150 ° C and exposure for 6 hours. At the end of exposure, the autoclave is cooled, the mother liquor is decanted, the zeolite powder is filtered off, washed and dried. Next, sequential ion exchange is carried out first in a solution of lanthanum nitrate (solution concentration 142.2 g / l, amount 240 ml) then in a solution of ammonium nitrate (solution concentration 26.3 g / l, amount 240 ml) under the same conditions.

After three times ion exchange, the Na ₂ O content was 0.8 wt. %, CaO - 0.5 wt. %, La ₂ O ₃ - 20.7 wt. %. The resulting powder is compressed to obtain tablets, from which the required fraction is prepared.

The resulting catalyst sample is dried and calcined. Then the resulting catalyst is tested in the alkylation reaction of isobutane with butylenes in a laboratory setup, at a temperature of 80 ° C, a pressure of 1.25 MPa, the isobutane: butylenes ratio in the feed is 10: 1, the volumetric feed rate for butylenes is 0.6 h ^-1 , the feed duration is raw materials 4 tsp

The test results are presented in table 1.

Example 2.

A catalyst sample was prepared on the basis of granular NaX zeolite without binder. Ion exchange of zeolite (30 g) for calcium is carried out in a solution of calcium nitrate (solution concentration 37.5 g / l, amount 240 ml) in an insert glass, which is installed in an autoclave with an inclination angle of 45 °; the rotation speed of the autoclave is 1 rpm, at a temperature of 150 ° C and holding for 6 hours. At the end of the holding, the autoclave is cooled, the mother liquor is decanted, the zeolite powder is filtered off, washed and dried. Next, sequential ion exchange is carried out, first in a solution of lanthanum nitrate (solution concentration 142.2 g / l, amount 240 ml), then in solutions of lanthanum and ammonium nitrates (solution concentration 142.2 and 26.3 g / l, respectively, the amount of solution 240 ml) under the same conditions.

After four times ion exchange, the Na ₂ O content was 0.7 wt. %, CaO - 0.7 wt. %, La ₂ O ₃ - 20.1 wt. %. No destruction of the granules was observed.

The obtained catalyst sample is dried, calcined and tested in the alkylation reaction of isobutane with butylenes under the conditions of example 1. The test results are shown in Table 1.

Example 3.

A catalyst sample was prepared on the basis of granular NaX zeolite without binder. Ion exchange of zeolite (30 g) for calcium is carried out in a solution of calcium nitrate (solution concentration 150 g / l, amount 240 ml) in an insert glass, which is installed in an autoclave with an inclination angle of 45 °, the rotation speed of the autoclave is 1 rpm, at a temperature 150 ° C and exposure for 6 hours. At the end of exposure, the autoclave is cooled, the mother liquor is decanted, the zeolite powder is filtered off, washed and dried. Then, sequential ion exchange is carried out first in a solution of lanthanum nitrate (solution concentration 142.2 g / l, amount 240 ml), then double ion exchange in a solution of ammonium nitrate (solution concentration 26.3 g / l, amount 240 ml) under the same conditions ...

After four-fold ion exchange, the Na ₂ 0 content was 0.4 wt. %, CaO - 0.9 wt. %, La ₂ O ₃ - 16.9 wt. %. No destruction of the granules was observed.

The obtained catalyst sample is dried, calcined and tested in the alkylation reaction of isobutane with butylenes under the conditions of example 1. The test results are shown in Table 1.

Example 4.

A catalyst sample was prepared on the basis of granular NaX zeolite without binder. Ion exchange of zeolite (30 g) for calcium is carried out in a solution of calcium nitrate (solution concentration 37.5 g / l, amount 240 ml) in an insert glass, which is installed in an autoclave with an inclination angle of 45 °; the rotation speed of the autoclave is 1 rpm, at a temperature of 150 ° C and holding for 6 hours. At the end of the holding, the autoclave is cooled, the mother liquor is decanted, the zeolite powder is filtered off, washed and dried. Next, a sequential ion exchange is carried out, first twice in a solution of lanthanum nitrate (solution concentration 142.2 g / l, amount 240 ml), then in a solution of ammonium nitrate (solution concentration 26.3 g / l, amount 240 ml) under the same conditions.

After four times ion exchange, the Na ₂ O content was 0.5 wt. %, CaO - 0.6 wt. %, La ₂ O ₃ - 18.3 wt. %. No destruction of the granules was observed.

The obtained catalyst sample is dried, calcined and tested in the alkylation reaction of isobutane with butylenes under the conditions of example 1. The test results are shown in Table 1.

Example 5.

The catalyst sample is prepared on the basis of granular NaX zeolite with a binder (clay, 30 wt.%). Ion exchange of zeolite (30 g) for calcium is carried out in a solution of calcium nitrate (solution concentration 82 g / l, amount 240 ml) in an insert glass, which is installed in an autoclave with an inclination angle of 45 °, the rotation speed of the autoclave is 1 rpm, at a temperature 155 ° C and exposure for 6 hours. At the end of exposure, the autoclave is cooled, the mother liquor is decanted, the zeolite powder is filtered off, washed and dried. Next, a sequential ion exchange is carried out, first in a solution of lanthanum nitrate (solution concentration 142.2 g / l, amount 240 ml), then in a solution of ammonium nitrate (solution concentration 26.3 g / l, amount 240 ml) under the same conditions.

After three times ion exchange, the Na ₂ O content was 0.9 wt. %, CaO - 0.3 wt. %, La ₂ O ₃ - 16.0 wt. %. The destruction of the granules was not observed, which is explained by the presence of a weakly bound binder.

The obtained catalyst sample is dried, calcined and tested in the alkylation reaction of isobutane with butylenes under the conditions of example 1. The test results are presented in table 1. Example 6.

A catalyst sample is prepared on the basis of granular NaX zeolite with a binder (aluminum hydroxide, 30 wt%). Ion exchange of zeolite (30 g) for calcium is carried out in a solution of calcium nitrate (solution concentration 82 g / l, amount 240 ml) in an insert glass, which is installed in an autoclave with an inclination angle of 45 °, the rotation speed of the autoclave is 1 rpm, at a temperature 150 ° C and exposure for 6 hours. At the end of exposure, the autoclave is cooled, the mother liquor is decanted, the zeolite powder is filtered off, washed and dried. Next, a sequential ion exchange is carried out, first in a solution of lanthanum nitrate (solution concentration 142.2 g / l, amount 240 ml), then in a solution of ammonium nitrate (solution concentration 26.3 g / l, amount 240 ml) under the same conditions.

After three times ion exchange, the Na ₂ O content was 0.9 wt. %, CaO - 1.0 wt. %, La ₂ O ₃ - 15.6 wt. %. No destruction of the granules was observed.

The obtained catalyst sample is dried, calcined and tested in the alkylation reaction of isobutane with butylenes under the conditions of Example 1.

The test results are presented in table 1.

Example 7 (comparative, according to AS USSR No. 1309383).

A sample of the catalyst is prepared on the basis of granular zeolite of type X. Ion exchange of zeolite (10 g) for calcium is carried out in a solution of calcium nitrate (solution concentration 40 g / l, amount 1020 ml) in an autoclave, heated to 150 ° C, held for 3 hours and cooled. At the end of the exposure, the autoclave is cooled, the mother liquor is drained. The obtained zeolite in the calcium form is treated with 450 ml of a mixture of solutions of nitrates of rare earth elements and ammonium (concentration 15 g / l for La ₂ O ₃ ). Then the zeolite is washed with demineralized water and the granules are dried, after which a weighed portion (10 g) of the rare earth calcium catalyst is poured with 20 ml of a solution of platinum tetraammoniumate (concentration 2.4 g / l by Pt) and water until the granules are completely immersed. The mixture is kept at room temperature with periodic stirring until the platinum is evenly distributed over the volume of the granule. Then the spent solution is drained, the tablets are washed, dried and calcined.

The catalyst obtained in this way has the following chemical composition Na ₂ O - 0.6 wt. %, CaO - 2.0 wt. %, La ₂ O ₃ - 15.1 wt. %, PtO - 0.55 wt. %. The resulting powder is compressed to obtain tablets, from which the required fraction is prepared.

The obtained catalyst sample is tested in the reaction of isobutane alkylation with butylenes in a laboratory micro-propulsion plant, at a temperature of 90 ° C, a pressure of 1.4 MPa, the isobutane: butylenes ratio in the raw material is 17: 1, the volumetric feed rate for butylenes is 0.4 h ^-1 , the duration supply of raw materials 7 h.

The test results are presented in table 1.

Example 8 (comparative, according to RF patent 2445164).

The catalyst sample is prepared on the basis of powdered zeolite of the faujasite type. Ion exchange of zeolite (40 g) for calcium is carried out in a solution of calcium chloride (solution concentration 60 g / l, amount 260 ml) in an autoclave without stirring at 160 ° C and holding for 3 hours. At the end of exposure, the autoclave is cooled, the mother liquor is drained. Next, ion exchange is carried out in solutions of nitrate of rare earth elements and ammonium (concentration 30 g / l, amount 210 ml) at a temperature of 160 ° C and holding for 3 hours.Then, palladium and nickel are applied to the rare earth calcium zeolite in two stages at a temperature of 25 ° C and 75 ° C with exposure at each stage for 1 hour. For the deposition of palladium, palladium tetraammonate with a concentration of 0.68 g / l for palladium is used, for the deposition of nickel - nickel nitrate with a concentration of 0.22 g / l for nickel.

The catalyst obtained in this way has the following chemical composition Na ₂ O - 0.26 wt. %, CaO - 0.8 wt. %, La ₂ O ₃ - 17.4 wt. %, PdO - 0.11 wt. %, NiO - 0.05 wt. %.

The obtained catalyst sample is tested in the alkylation reaction of isobutane with butylenes in a laboratory micro-propylene plant, at a temperature of 90 ° C, a pressure of 1.6 MPa, the isobutane: butylenes ratio in the feed is 27: 1, the space velocity of the raw material for the raw material is 1.2 (corresponds to the space velocity of the feed for butylenes 0.6 h ^-1 , duration of raw material supply 7 h).

The test results are presented in table 1.

Example 9 (comparative, according to RF patent No. 2672063 C1).

A catalyst sample is prepared on the basis of a granular, binder-free NaX type zeolite. Ion exchange of zeolite (30 g) for calcium is carried out in a solution of calcium nitrate (solution concentration 37.5 g / l, amount 240 ml) at a temperature of 85 ° C and holding for 2 h with mechanical stirring over the granules. The treated granules are filtered off, washed, dried at 120 ° C for 10 h, then calcined at 350 ° C for 1.5 h and 450 ° C for 2.5 h. Then, sequential ion exchange is carried out, first twice in a solution of lanthanum nitrate (solution concentration 135 g / l, amount 240 ml), then in a solution of ammonium nitrate (solution concentration 26.3 g / l, amount 240 ml) under the same conditions.

After four times ion exchange, the Na ₂ O content was 0.7 wt. %, CaO - 2.4 wt. %, La ₂ O ₃ - 19.1 wt. %. Significant destruction of the granules was observed.

The resulting catalyst sample was tested in the alkylation reaction of isobutane with butylenes under the conditions of Example 1.

The test results are presented in table 1.

Thus, the proposed device allows high-quality ion exchange without destruction of zeolite granules.

Also, this technical solution allows you to increase the activity for the conversion of butylenes, almost up to 100 wt. %, the yield of the product (alkyl benzene) and the selectivity of the alkylation process of isobutane with butylenes with respect to the target product - isooctanes (iso-C8) up to 83.6 wt. % compared to 73.5 wt. % according to RF patent 2445164 when using an autoclave without stirring, and selectivity for TMP up to 67.1 wt. % with 47.3 wt. % according to RF patent No. 2672063 C1 when using mechanical stirring of the solution and zeolite, and when using this device, the zeolite granules do not collapse and do not become dusty when using zeolite without a binder. In comparison with the data with A.w. USSR No. 1309383 there is an increase in the yield of alkylate and, as a result, the removal of alkylate from 1 g of catalyst from 0.78 g of alkylate / g of catalyst to 1.188 g of alkylate / g of catalyst.

* - trimethylpentanes

Claims (2)

1. A device for processing zeolite by ion exchange, including an autoclave made in the form of a cylindrical body filled with a reaction medium and equipped with a sealed lid, and placed in a split heating jacket, characterized in that the autoclave body is additionally equipped with a Teflon glass tightly fitting to its walls; an insert, the body is fixed in a stationary rack with the possibility of adjusting its angle of inclination when the autoclave is installed at an angle of 30-60 °, at the base of the rack there is an engine connected on one side with a body rotation frequency regulator, and on the other, with a rotary mechanism that ensures rotation of the body at a speed of up to 3.0 rpm inside a stationary heating jacket coaxial to it, which is rigidly connected to the rack, the autoclave lid is equipped with a pocket for a thermocouple, which is installed in the reaction medium, and a manometer. 2. A method of obtaining a catalyst for the alkylation of isobutane with butylenes by sequential ion exchange of a zeolite of the NaX type for calcium, lanthanum and ammonium, drying and calcination, characterized in that the ion exchange is carried out under hydrothermal conditions in an aqueous solution of salts of the said cations in the device according to claim 1 at setting the autoclave at an angle of 30-60 ° at a temperature of 150-180 ° C for the time required to convert the original zeolite into a form substituted with calcium, lanthanum and ammonium when the Na ₂ O content in the final catalyst is less than 1 wt%.

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