RU2840865C1 - High-silica zeolite-containing oligomerisation catalyst, method for preparation and use thereof - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: group of inventions relates to a zeolite-containing oligomerisation catalyst, a method for preparation and use thereof. Described is a method which includes preparing a support obtained with the addition of a binding component, which is added without pre-wetting the zeolite with water, using as a peptizing module an aqueous solution of nitric acid with concentration of 15-30 wt.%, decontaminating the outer surface of the crystalline zeolite of type ZSM-5 by treating with an organosilicon compound at a catalyst moulding step and subsequent calcination, wherein active component used is zeolite ZSM-5 with molar ratio Si/Al equal to 20-1070. Invention also describes a zeolite-containing oligomerisation catalyst and use of the zeolite-containing catalyst for oligomerisation of olefin-containing fractions of hydrocarbons.

EFFECT: zeolite-containing oligomerisation catalyst with improved properties which enable to reduce coke formation and prolong the duration of the cycle between regeneration runs, a method for preparation and use thereof.

10 cl, 1 tbl, 13 ex

Description

The group of inventions relates to a zeolite-containing oligomerization catalyst, a method for its preparation and use.

The prior art provides methods for producing zeolites with a deactivated surface. Zeolites modified to deactivate the outer surface are recommended for use in catalytic processes. Various modification methods result in zeolites with different properties, and therefore the area of use of the zeolite directly depends on the method of modification.

A method for producing zeolite ZSM-5 is known, including its modification with organosilicon compounds in the gas phase. The method includes treating the zeolite with vapors of an organosilicon compound containing at least two silicon atoms. The resulting modified zeolite is recommended for converting aromatic hydrocarbons into products containing para-isomers of dialkylbenzenes (US 5516736, 14.05.1996).

A method for producing a selective metallosilicate composition used for converting alkylaromatic compounds is known. The method involves contacting a mesoporous metallosilicate with an organosilicon compound in a solvent, reacting the metallosilicate treated with the organosilicon compound with water, repeating the above steps, and calcining the catalyst in an oxygen-containing atmosphere (US 7094941, 22.08.2006).

A method is known for treating molecular sieves of the SAPO or ZSM-34 type with tetraethyl orthosilicate or trimethylethyl silicate in the liquid or gas phase in a closed system for more than 20 days, followed by high-temperature calcination. The resulting product is proposed for use in producing olefins from oxygen-containing organic raw materials (US 2005/0003957, 06.01.2005).

A method for modifying MFI zeolite is known, which is pre-calcined, then modified with a solution of organosilicon compound in an organic solvent, after which it is mixed with a binding agent and subjected to granulation. The zeolite is recommended for use in hydrocarbon conversion processes in the production of paraxylene (US 6066770, 23.05.2000).

A method is known for converting light olefins on zeolites with a deactivated outer surface of the crystals, which is deactivated by treating the zeolite from the group: ZSM-22, ZSM-23, ZSM-57 with oxides of rare earth metals or yttrium. The oligomerization process is carried out at 200-300 °C, 0.18-10 h ^-1 and a pressure of 5 MPa. Conversion of 2-butene under these conditions reaches 91% with selectivity into liquid products C ₅₊ up to 97%.

The disadvantages of the method are high pressure during oligomerization, the presence of high-boiling oligomers C ₁₆₊ in the products, as well as a low degree of branching of the oligomeric products, which negatively affects the octane number of the liquid fraction (US 7759533, 2010).

A method is known for modifying a ZSM-5 type zeolite, including its treatment with a reagent selected from tetraethyl orthosilicate, or ammonium heptamolybdate, or a phosphoric acid compound, in which the original zeolite is not calcined before modification. The resulting modified product has blocked centers in the pores and surface acid centers with protected acid centers. The product is recommended for the conversion of oxygen-containing raw materials, including hydrocarbons, methanol and dimethyl ether, into high-octane gasoline (US 8450545, 28.05.2013).

The disadvantage of the known method is that the obtained product does not have selectivity in the processes of catalytic production of gasoline from the butane-butylene fraction (BBF).

A method for modifying a crystalline zeolite of the ZSM-5 type is known, which includes deactivation of its outer surface by treating the original zeolite with an organosilicon compound and calcining the treated zeolite. The zeolite is treated by impregnation according to its moisture capacity with a solution of tetraethyl orthosilicate or polymethylsiloxane (PMS) in an organic solvent.

The advantages of this method include increased selectivity and a high degree of conversion when obtaining the C ₅₊ fraction.

The disadvantage of the method is that an organic solvent is used at the impregnation stage, and also that the treatment with an organosilicon compound and the calcination of the treated zeolite are separate technological stages (RU Patent No. 2555879, 11/29/2013).

The closest to the proposed method in technical essence is a method for preparing a zeolite-containing catalyst of the ZSM-5 type, including deactivation of its outer surface by treating the initial zeolite with an organosilicon compound at the molding stage and calcination of the treated zeolite, wherein a zeolite of the ZSM-5 type with a molar ratio of Si/Al equal to 20-60 is used as the active component.

The advantages of this method include a reduction in the number of technological stages for preparing a catalyst with a deactivated outer surface while maintaining high conversion and selectivity in obtaining the target C ₅₊ fraction.

The disadvantage of this method is high coke formation, which leads to a decrease in the inter-regeneration mileage in long-term experiments (RU patent No. 2633882, 20.07.2016).

The technical result of the present invention is a zeolite-containing oligomerization catalyst with improved properties that make it possible to reduce coke formation and increase the duration of the inter-regeneration run, a method for its preparation and use.

The technical result is achieved in that a method is proposed that includes preparing a carrier obtained with the addition of a binding component introduced without preliminary wetting of the zeolite with water, using an aqueous solution of nitric acid with a concentration of 15-30% by weight as a peptizing module, deactivating the outer surface of a crystalline zeolite of the ZSM-5 type by treating it with an organosilicon compound at the stage of forming the catalyst and subsequent calcination, wherein a zeolite of the ZSM-5 type with a molar ratio of Si/Al equal to 20-1070 is used as the active component.

At the same time, high selectivity and conversion of olefin-containing raw materials into the target fraction C ₅₊ are maintained. In addition, the proposed method optimizes the formulation for obtaining the carrier by mixing zeolite and binder powders without preliminary wetting of the zeolite with water, using an aqueous solution of nitric acid with a concentration of 15-30% by weight, and does not require high-temperature steam treatment of the catalyst before operation to increase its resistance to deactivation.

Preferably, tetraethoxysilane (TEOS) or polymethylsiloxane (PMS) is used as the organosilicon compound.

Preferably, γ-aluminum oxide is used as a binder component of the carrier in an amount of 20-60% by weight.

Preferably, calcination of the molded catalyst is carried out at a temperature of 450-600°C.

Preferably, nitric acid with a concentration of 15-30% by weight is used as a peptizing solution in the manufacture of the carrier.

As an embodiment, the method may include an additional stage in which the formed catalyst is impregnated with an aqueous solution of a metal salt selected from the series: Ga, Zn, La, followed by calcination.

As an embodiment, the method may provide for the introduction of an additional component - a plasticizer - into the carrier molding mass; preferably, glycerin or ethylene glycol is used as the plasticizer.

When carrying out the method in the volume of the set of features indicated above, a product is obtained which is a zeolite-containing catalyst of the ZSM-5 type with a deactivated outer surface for use in the process of oligomerization of an olefin-containing fraction of hydrocarbons.

Preferably, the H-form of zeolite ZSM-5 is used.

The proposed group of inventions provides the possibility of producing motor gasoline from an olefin-containing hydrocarbon fraction. The production process is reduced to contact of the olefin-containing raw material at a temperature of 300-450°C, a pressure of 1.5 MPa, a volumetric feed rate of liquid raw material of 1.5 h ^-1 on a stationary bed of solid catalyst particles, which is a catalyst prepared according to the proposed method with a deactivated outer surface.

Preferably, butane-butylene, propane-propylene or pentane-amylene fractions are used as olefin-containing fractions. As confirmed by the examples of the implementation of the claimed method for preparing the catalyst and the results of using the catalyst in the oligomerization reaction presented below, the claimed technical result is achieved.

The catalyst is obtained in the following way.

The initial products used are the H-form of zeolite ZSM-5 with a molar ratio of Si/Al = 20-1070. Pseudoboehmite is added to the zeolite in a ratio of zeolite: aluminum oxide = (60-80) : (40-20) based on dry weight, after mixing the dry mass, water and TEOS or PMS are added, then an aqueous solution of nitric acid (HNO3) with a concentration of 15-30% by weight is added, extrudates are formed and dried at room temperature, then at 110°C, after which they are calcined at a temperature of 450°C to 600°C.

As an embodiment of the invention, glycerin or ethylene glycol is added to the molding mass of the carrier as a plasticizer.

In some embodiments, modifiers are added to the catalyst. For this purpose, the formed catalyst after calcination is impregnated with an aqueous solution of a metal salt selected from the series: Ga or La or Zn and dried at 110°C. After this, the sample is placed in a reactor and calcined in a stream of dry air at a temperature of 450°C to 600°C.

Oligomerization of the olefin-containing hydrocarbon fraction is generally carried out as follows. Preliminary preparation of the catalyst is carried out by heating it in a stream of inert gas (nitrogen, helium) to 300°C and calcining at this temperature for 30 minutes. The olefin-containing hydrocarbon fraction is fed into a flow-type reactor with a fixed catalyst bed. At the reactor outlet, the products obtained are separated into liquid and gaseous, the component composition is determined by the chromatographic method. As the catalyst is deactivated, the catalyst temperature is gradually increased to compensate for the decrease in conversion. The interregeneration run is determined by the time it takes for the catalyst bed to reach a temperature of 450°C.

Below are examples illustrating the invention, but not limiting it.

Example 1.

The starting products are the H-form of zeolite ZSM-5 (Si/Al=130), TEOS and pseudoboehmite, which are molded and calcined. For this purpose, pseudoboehmite is added to the zeolite in a ratio of zeolite: aluminum oxide = 70:30 based on dry weight, after mixing the dry mass, water and TEOS are added, then an aqueous solution of nitric acid ( _HNO3 with a concentration of 15-30% by weight) is added, extrudates are molded and dried at room temperature, then at 110°C, after which they are calcined at 600°C. Then a modifier is added to the catalyst - 1.0 wt. % Ga. For this purpose, after calcination, the molded catalyst is impregnated with an aqueous solution of gallium salt and dried at 110°C. After that, the sample is placed in a reactor and calcined in a stream of dry air at 600°C.

The catalyst is placed in a flow reactor, purged with nitrogen at a temperature of 300°C and a pressure of 1.5 MPa for 1 hour, then the feedstock is fed at the same temperature and pressure - a butane-butylene fraction containing 71% butylenes and 28% butanes, with a mass velocity of 1.5 h ^-1 . As the catalyst is deactivated, the catalyst temperature is gradually raised from 300 to 450°C to compensate for the decrease in conversion. The interregeneration run is determined by the time it takes for the catalyst layer to reach a temperature of 450°C.

The catalyst's interregeneration run was 41 days, the coke content on the catalyst after the run was 0.25 g/g of catalyst. The results of the experiment are presented in Table 1.

Example 2.

The oligomerization process is carried out as in example 1, the difference is that the H-form of zeolite ZSM-5 (Si/Al=80) is used in the synthesis of the catalyst.

The catalyst's interregeneration run was 32 days, the coke content on the catalyst after the run was 0.27 g/g of catalyst. The results of the experiment are presented in Table 1.

Example 3.

The oligomerization process is carried out as in example 1, the difference is that the H-form of zeolite ZSM-5 (Si/Al=1070) is used in the synthesis of the catalyst.

The catalyst's interregeneration run was 37 days, the coke content on the catalyst after the run was 0.21 g/g of catalyst. The results of the experiment are presented in Table 1.

Example 4. (Comparative)

The oligomerization process is carried out as in example 1, the difference is that the H-form of zeolite ZSM-5 (Si/Al=20) is used in the synthesis of the catalyst.

The catalyst's interregeneration run was 33 days, the coke content on the catalyst after the run was 0.35 g/g of catalyst. The results of the experiment are presented in Table 1.

A comparison of examples 1, 2, 3 and example 4 illustrates the advantages of the proposed method for preparing the catalyst, since the use of a zeolite with a high Si/Al ratio of 20-1070 allows for an increase in the catalyst's regeneration life and, at the same time, a reduction in coke formation.

Example 5.

The oligomerization process is carried out as in example 1, the difference is that the catalyst used is the same as in example 1, but without adding a modifier.

The process indicators are presented in Table 1.

Example 6.

The initial products used are the H-form of zeolite ZSM-5 (Si/Al=130), TEOS and pseudoboehmite, which are subjected to molding and calcination. For this purpose, pseudoboehmite is added to the zeolite in the ratio zeolite: aluminum oxide = 60: 40 based on dry weight, after mixing the dry mass, water and TEOS are added, extrudates are molded and dried at room temperature, then at 110°C, after which they are calcined at 450°C. Then a modifier is added to the catalyst - 1.0 wt. % Zn. For this purpose, after calcination, the molded catalyst is impregnated with an aqueous solution of zinc salt and dried at 110°C. After that, the sample is placed in a reactor and calcined in a stream of dry air at 450°C.

The oligomerization process is carried out as in example 1. The process indicators are presented in table 1.

Example 7.

The initial products used are the H-form of zeolite ZSM-5 (Si/Al=130), PMS and pseudoboehmite, which are subjected to molding and calcination. For this purpose, pseudoboehmite is added to the zeolite in the ratio of zeolite: aluminum oxide = 80: 20 based on dry weight, after mixing the dry mass, water and PMS are added, extrudates are molded and dried at room temperature, then at 110°C, after which they are calcined at 480°C. Then a modifier is added to the catalyst - 1.0 wt. % La. For this purpose, after calcination, the molded catalyst is impregnated with an aqueous solution of lanthanum salt and dried at 110°C. After that, the sample is placed in a reactor and calcined in a stream of dry air at 500°C.

The oligomerization process is carried out as in example 1. The process indicators are presented in table 1.

Example 8.

The oligomerization process is carried out as in example 3, the difference is that the catalyst used is the same as in example 3, but zinc salt is used as a modifier instead of gallium, and also that a propane-propylene fraction containing 80% propylene and 20% propane is used as raw material.

The process indicators are presented in Table 1.

Example 9.

The initial products used are the H-form of zeolite ZSM-5 (Si/Al=1070), PMS and pseudoboehmite, which are subjected to molding and calcination. For this purpose, pseudoboehmite is added to the zeolite in the ratio of zeolite: aluminum oxide = 70:30 based on dry weight, after mixing the dry mass, water and PMS are added, extrudates are molded and dried at room temperature, then at 110°C, after which they are calcined at 480°C. Then a modifier is added to the catalyst - 1.0 wt. % La. For this purpose, after calcination, the molded catalyst is impregnated with an aqueous solution of lanthanum salt and dried at 110°C. After that, the sample is placed in a reactor and calcined in a stream of dry air at 450°C.

The oligomerization process is carried out as in example 3, the difference is that the catalyst used is the same as in example 3, but lanthanum salt is used as a modifier instead of gallium.

The process indicators are presented in Table 1.

The oligomerization process is carried out as in example 3, the difference is that the catalyst used is the same as in example 3, but lanthanum salt is used as a modifier instead of gallium.

The process indicators are presented in Table 1.

Example 10.

The oligomerization process is carried out as in example 1, the difference is that the H-form of zeolite ZSM-5 (Si/Al=660) is used in the synthesis of the catalyst.

The process indicators are presented in Table 1.

Example 11.

The initial products used are the H-form of zeolite ZSM-5 (Si/Al=1070), PMS and pseudoboehmite, which are subjected to molding and calcination. For this purpose, pseudoboehmite is added to the zeolite in a ratio of zeolite: aluminum oxide = 60:40 based on dry weight, after mixing the dry mass, water and TEOS are added, extrudates are molded and dried at room temperature, then at 110°C, after which they are calcined at 500°C.

The oligomerization process is carried out as in example 1, the difference being that the pentane-amylene fraction containing 40% amylenes and 60% pentanes is used as raw material.

Example 12.

The oligomerization process is carried out as in example 1, the difference being that the propane-propylene fraction containing 80% propylene and 20% propane is used as raw material.

Example 13.

The initial products used are the H-form of zeolite ZSM-5 (Si/Al=130), TEOS and pseudoboehmite, which are subjected to molding and calcination. For this purpose, pseudoboehmite is added to the zeolite in the ratio zeolite: aluminum oxide = 60: 40 based on dry weight, after mixing the dry mass, water and TEOS are added, then a plasticizer - glycerin - is added, extrudates are molded and dried at room temperature, then at 110 ° C, after which they are calcined at 450 ° C. Then a modifier is added to the catalyst - 1.0 wt. % Ga. For this purpose, after calcination, the molded catalyst is impregnated with an aqueous solution of gallium salt and dried at 110 ° C. After that, the sample is placed in a reactor and calcined in a stream of dry air at 550 ° C.

The oligomerization process is carried out as in example 1. The process indicators are presented in table 1.

The process indicators are presented in Table 1.

Table 1 - Process indicators Example No. Preparation of the catalyst Content of binder (γ-Al ₂ O ₃ ) in the catalyst, mass % Hydrocarbon fraction Catalytic properties Composition of the molded mixture Si/Al molar ratio in the starting zeolite Calcination temperature, °C Modifier metal Inter-regeneration mileage, days Coke content, g/g catalyst 1 ZSM-5
pseudoboehmite
TEOS 130 600 Ga 30 Butane-butylene 41 0.25 2 ZSM-5
pseudoboehmite
TEOS 80 600 Ga 30 Butane-butylene 32 0.27 3 ZSM-5
pseudoboehmite
TEOS 1070 600 Ga 30 Butane-butylene 37 0.21 4 ZSM-5
pseudoboehmite
TEOS 20 600 Ga 30 Butane-butylene 33 0.35 5 ZSM-5
pseudo-bemi
TEOS 130 600 - 30 Butane-butylene 39 0.24 6 ZSM-5
pseudoboehmite
TEOS 130 450 Zn 60 Butane-butylene 35 0.22 7 ZSM-5
pseudoboehmite
PMS 130 480 La 20 Butane-butylene 40 0.27 8 ZSM-5
pseudoboehmite
TEOS 1070 500 Zn 30 Propane-propylene 35 0.23 9 ZSM-5
pseudoboehmite
TEOS 1070 450 La 30 Butane-butylene 37 0.22 10 ZSM-5
pseudoboehmite
TEOS 660 500 Ga 30 Butane-butylene 40 0.23 11 ZSM-5
pseudoboehmite
PMS 1070 500 - 40 Pentane-amylene 35 0.23 12 ZSM-5 pseudoboehmite TEOS 130 600 Ga 30 Propane-propylene 37 0.24 13 ZSM-5
pseudoboehmite
TEOS
glycerol 130 550 Ga 40 Butane-butylene 42 0.25

Claims (10)

1. A method for preparing a zeolite-containing oligomerization catalyst, including preparing a carrier obtained with the addition of a binding component introduced without preliminary wetting of the zeolite with water, using an aqueous solution of nitric acid with a concentration of 15-30% by weight as a peptizing module, deactivating the outer surface of a crystalline zeolite of the ZSM-5 type by treating it with an organosilicon compound at the stage of forming the catalyst and subsequent calcination, wherein a zeolite of the ZSM-5 type with a molar ratio of Si/Al equal to 20-1070 is used as the active component. 2. The method according to paragraph 1, characterized in that tetraethoxysilane or polymethylsiloxane is used as the organosilicon compound. 3. The method according to claim 1, characterized in that the carrier contains γ-aluminum oxide as a binding component in an amount of 20-60% by weight. 4. The method according to item 1, characterized in that calcination is carried out at a temperature of 450-600°C. 5. The method according to item 1, characterized in that the catalyst is modified by impregnation with an aqueous solution of a metal salt selected from the series: Ga, Zn, La after molding, followed by calcination. 6. The method according to paragraphs 1-3, characterized in that glycerin or ethylene glycol is added to the molding mass of the carrier as a plasticizer. 7. A zeolite-containing oligomerization catalyst obtained by the method according to item 1. 8. A zeolite-containing oligomerization catalyst according to claim 6, characterized in that the H-form of zeolite ZSM-5 is used. 9. Use of a zeolite-containing oligomerization catalyst according to paragraph 6 for the oligomerization of olefin-containing hydrocarbon fractions. 10. The use of a zeolite-containing oligomerization catalyst according to paragraph 8, characterized in that butane-butylene, propane-propylene or pentane-amylene fractions are used as olefin-containing fractions.