RU2559056C1 - Catalyst of aromatisation of synthetic normal liquid paraffin hydrocarbons and method of obtaining thereof - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: catalyst contains carrier from porous zeolite and binding agent and catalytically active substance - platinum. Carrier additionally contain gallium oxide nanopowder with gibbsite powder with particle size not more than 40 mcm being used as binding agent and zeolite KL with particle size not more than 0.10 mm being used as zeolite. ratio of ingredients is within the following range, wt %: platinum - 0.3-0.8, gibbsite - 16-60, zeolite KL - 39.12-83.68, gallium oxide - 0.02-0.08. Claimed catalyst possesses higher activity and selectivity with respect to formation of aromatic hydrocarbons.

EFFECT: invention also relates to method of obtaining such catalyst.

2 cl, 1 tbl, 3 ex

Description

The invention relates to oil refining and petrochemicals and can be used in the production of aromatization catalysts for normal paraffin hydrocarbons from both crude oil and synthetic hydrocarbons. The cyclization process is one of the most important in the processing of synthetic hydrocarbons due to the almost complete absence of aromatic compounds in the composition of Fischer-Tropsch synthesis products.

In recent decades, the development of fundamentally new catalysts for the aromatization of normal paraffin hydrocarbons containing platinum and zeolite L. Zeolite L belongs to the group of high-silica zeolites and is characterized by the absence of acid centers. The basicity of a carrier containing zeolite L in potassium form (zeolite KL) is a necessary property for the selective occurrence of aromatization reactions of normal paraffin hydrocarbons. In the channels of zeolite KL as a result of the course of isomerization reactions, equilibrium is maintained in a mixture of branched, cyclic and normal alkanes.

The use of a non-acid component in the catalyst composition is a fundamentally new approach to creating a catalyst for the aromatization of normal paraffin hydrocarbons, since the classic alumina-platinum reforming catalyst is bifunctional and is characterized by the presence of metal and acid centers.

An important criterion for the aromatization catalyst is the Pt particle size, which largely determines the occurrence of side reactions (mainly, hydrogenolysis of alkanes). P. Meriaudeau, C. Naccache. Catal Rev. - Sci. Eng. 39, 1997, p. 5-48. The small particle size of platinum (less than 1-2 nm) in combination with one-dimensional channels of KL zeolite limits the degree of hydrogenolysis of alkanes, increasing the efficiency of the catalytic system.

Known platinum-gallium zeolite catalyst for aromatization of hydrocarbons containing gallium-silicon zeolite and platinum deposited on gallium-silicon zeolite. This catalyst consists essentially of platinum on an MFI zeolite, the lattice of which consists of gallium, silicon and oxygen. A method of producing a platinum-gallium zeolite catalyst for aromatization of hydrocarbons involves the preparation of a zeolite containing silicon and gallium, the deposition of platinum by impregnation on the specified zeolite and calcination of the zeolite. RU 2367643 C2, 09.20.2009.

The disadvantages of the catalyst include a complex procedure for its activation, as well as low activity in the process of aromatization of alkanes.

Known platinum catalyst for producing aromatic hydrocarbons, containing as a carrier zeolite or alumina, and a modifier, for example germanium, tin, lead, rhenium, gallium, indium or titanium. To prepare the system using the method of impregnation with organometallic compounds. Depending on the composition of the system, both single and multi-stage impregnation of the oxide component is used. In the case of multi-stage impregnation, intermediate calcination is used. As an alternative preparation of the catalyst indicated the introduction of modifiers in the composition of the media at the gel stage before the molding process. US 6153090 A1, 11.28.2000.

The disadvantage of the proposed method for the preparation of the catalyst is the complexity of its preparation and high cracking activity.

Closest to the proposed group of inventions is a catalyst for the aromatization of a hydrocarbon mixture enriched with normal C ₆ -C ₇ alkanes and a method for producing it. The catalyst contains platinum and a zeolite-containing support based on industrial zeolite L (Tosoh, Ltd, Japan). The carrier is prepared by mixing powders of zeolite L and a binder, followed by extrusion. The resulting extrudates are dried and calcined, treated with a solution of the corresponding halide (chloride and / or fluoride), dried and calcined. Before the introduction of the active component, the carrier is subjected to repeated washing with distilled water. Platinum is introduced from a solution of platinum tetraaminochloride, followed by drying. The method involves the introduction of a promoter in the preparation of a carrier with intermediate calcination before the introduction of platinum. US 6,190,539 B1, 02.20.2001.

A disadvantage of the known catalyst and the method of its preparation are low catalytic activity and low aromatic hydrocarbon content in the product With ₅₊ - 46.5-48.5 wt.%.

The technical task of the proposed group of inventions is the development of a catalyst for the aromatization of normal liquid paraffin hydrocarbons with increased activity and selectivity in relation to the formation of aromatic hydrocarbons and the method for its preparation.

The technical result from the implementation of the proposed group of inventions is to increase the catalytic activity of the catalyst by increasing the yield and selectivity for the target product.

The technical problem is solved in that the aromatization catalyst for synthetic liquid normal paraffin hydrocarbons contains a carrier of porous KL zeolite with a particle size of not more than 0.10 mm, a gallium oxide nanopowder and a binder, in which it contains gibbsite powder with a particle size of not more than 40 microns, the catalytically active substance is platinum, and the ratio of ingredients is in the following ranges, wt.%:

Platinum 0.3-0.8 Gibbsit 16-60 Zeolite KL 39.12-83.68 Gallium oxide 0.02-0.08.

In accordance with the task developed a method for producing the claimed catalyst.

The method of producing the claimed aromatization catalyst for normal paraffin hydrocarbons is characterized in that the carrier is prepared by sequentially mixing KL zeolite powder with a particle size of not more than 0.10 mm, gallium oxide nanopowder and a binder — gibbsite powder with a particle size of not more than 40 microns, the mixture is moistened and peptized 5-15% solution of nitric acid, mixing until a homogeneous mass is obtained, which is granulated by extrusion, the obtained granules are dried and calcined, on the calcined granules on osyat platinum cation exchange of an aqueous solution having a concentration of platinum tetraammiakata platinum 1.5-5.0 mg / ml, followed by drying.

Before carrying out the aromatization process of synthetic normal liquid paraffin hydrocarbons, the catalyst was reduced with a hydrogen-containing gas at a temperature of 450 ° C.

The efficiency of the catalyst was evaluated in the process of aromatization of synthetic normal liquid paraffin hydrocarbons by passing a hydrogen-containing gas and feedstock with a molar ratio of hydrogen to feedstock from 1: 1 to 10: 1 through a fixed catalyst bed loaded into a tubular reactor with a space velocity of 0.5-4 h ^-1 in the temperature range 340-550 ° C under a pressure of 0.1-4 MPa in yield and content of aromatic hydrocarbons in the products.

A specific implementation of the method is disclosed in the following examples.

Example 1

An example illustrates the preparation of a platinum catalyst based on a granular zeolite-containing carrier that uses commercial high-silica zeolite KL (Zeolyst) with a particle size of not more than 0.10 mm, gallium oxide nanopowder with a particle size of 30 nm (Chengdu Xinweixin Light Industry Co. Ltd.) gibbsite powder with a particle size of not more than 40 microns as a binder.

A sample of the composition catalyst, wt.%: Pt - 0.3, high-silica zeolite KL - 83.68, gallium oxide - 0.02, gibbsite - 16.0, prepared in the following way:

To obtain a granular support, 8.5 g of powdered high-silica zeolite KL, 0.025 g of gallium oxide nanopowder and 1.8 g of gibbsite powder are placed in a porcelain bowl, mixed thoroughly. A 5% solution of HNO ₃ containing 0.0645 ml of HNO ₃ (65%) and 6.2 ml of distilled water was added. The mixture is thoroughly mixed until a homogeneous mass is obtained and extruded on a piston extruder through a 1.5 mm diameter die. The extrudates are held in air for 6 hours. The extrudates are then placed in a muffle furnace. The drying mode is stepwise: 60 ° C - 2 hours, 80 ° C - 2 hours, 110 ° C - 2 hours. Next, the temperature is increased at a rate of 2 ° C / min to a temperature of 550 ° C. At a temperature of 550 ° C, they stand for 4 hours.

Platinum is introduced by cation exchange from an aqueous solution of [(NH ₃ ) ₄ Pt] Cl ₂ . The complex compound, platinum tetraammoniac, [Pt (NH ₃ ) ₄ ] Cl ₂ , is obtained by reacting ammonium hexachloroplatinate (NH ₄ ) ₂ PtCl ₆ with concentrated ammonia solution (25%).

20 ml of a prepared solution with a concentration of platinum of 1.5 mg / ml is added to 10 g of calcined carrier. The mixture is stirred in a porcelain dish for 10 minutes at room temperature and left in the air for 10 hours, then the excess solution is separated by decantation. The resulting catalyst is dried in an electric cabinet. The drying mode is as follows: 60 ° C - 2 hours, 80 ° C - 2 hours, 110 ° C - 2 hours.

Before the process, the catalyst sample is activated in a stream of hydrogen (v = 3000 h ^-1 ) at a temperature of 450 ° C for 3 hours. Aromatization is carried out in a tubular reactor with a stationary catalyst layer at a pressure of 0.1 MPa, the molar ratio of hydrogen to feed 3: 1 and a space velocity of 2 h ^-1 in the temperature range 340-550 ° C.

Example 2

An example illustrates the preparation of a platinum catalyst based on a granular zeolite-containing carrier that uses commercial high-silica zeolite KL (Zeolyst) with a particle size of not more than 0.10 mm, gallium oxide nanopowder with a particle size of 30 nm (Chengdu Xinweixin Light Industry Co. Ltd.) as a binder - gibbsite powder with a particle size of not more than 40 microns, platinum with a particle size of 0.8 nm.

A sample of the catalyst composition, wt.%: Pt - 0.5, zeolite KL - 60.35, gallium oxide - 0.03, gibbsite - 39.12, prepared in the following way.

To obtain a granular support, 6.1 g of powdered high-silica zeolite KL, 0.032 g of gallium oxide nanopowder and 4.0 g of gibbsite powder are placed in a porcelain bowl, mixed thoroughly. A 10% HNO ₃ solution containing 0.129 ml of HNO ₃ (65%) and 6.15 ml of distilled water was added. The mixture is thoroughly mixed until a homogeneous mass is obtained and extruded on a piston extruder through a 1.5 mm diameter die. The extrudates are held in air for 7 hours. The extrudates are then placed in a muffle furnace. The drying mode is stepwise: 60 ° C - 2 hours, 80 ° C - 2 hours, 110 ° C - 2 hours. Next, the temperature is increased at a speed of 2 ° C / min to 550 ° C. At a temperature of 550 ° C, they stand for 4 hours.

Platinum is introduced according to Example 1. 20 ml of a prepared solution with a concentration of platinum of 2.5 mg / ml is added to 10 g of the obtained carrier. The mixture is stirred in a porcelain cup for 5 minutes at room temperature and left in air for 10 hours, then the excess solution is separated by decantation. After that, the catalyst is dried in an electric cabinet. The drying mode is as follows: 60 ° C - 2 hours, 80 ° C - 2 hours, 110 ° C - 2 hours.

Before the process, the catalyst sample is activated in a stream of hydrogen at a temperature of 450 ° C for 3 hours at a volumetric rate of hydrogen supply of 3000 h ^-1 . Aromatization is carried out in a tubular reactor with a stationary catalyst bed at a pressure of 1 MPa, a molar ratio of hydrogen to feed 1: 1 and a space velocity of 0.5 h ^-1 in the temperature range 340-550 ° C.

Example 3

An example illustrates the preparation of a platinum catalyst based on a granular zeolite-containing carrier that uses commercial high-silica zeolite KL (Zeolyst) with a particle size of not more than 0.10 mm, gallium oxide nanopowder with a particle size of 30 nm (Chengdu Xinweixin Light Industry Co. Ltd.) as a binder, gibbsite powder with a particle size of not more than 40 microns, platinum with a particle size of 1.2 nm.

A sample of the catalyst composition, wt.%: Pt - 0.8, zeolite KL - 39.93, gallium oxide - 0.06, gibbsite - 59.15, prepared in the following way.

To obtain a granular support, 4.0 g of powdered commercial high-silica zeolite KL, 0.063 g of gallium oxide nanopowder and 6.0 g of gibbsite powder are placed in a porcelain bowl, mixed thoroughly. A 15% HNO ₃ solution containing 0.1935 ml of HNO ₃ (65%) and 6.1 ml of distilled water was added. The mixture is thoroughly mixed until a homogeneous mass is obtained and extruded on a piston extruder through a 1.5 mm diameter die. The extrudates are kept in air for 7 hours and crushed to a fraction of 1.5 × 4-5 mm. Then the extrudates are placed in a muffle furnace. The drying mode is stepwise: 60 ° C - 2 hours, 80 ° C - 2 hours, 110 ° C - 2 hours. Next, the temperature is increased at a rate of 2 ° C / min to a temperature of 550 ° C. At a temperature of 550 ° C, incubated for 4 hours

Platinum is introduced according to Example 1. 16 ml of a prepared solution with a concentration of platinum of 5.0 mg / ml is added to 10 g of the obtained carrier. The mixture is stirred in a porcelain dish for 10 minutes at room temperature and left in the air for 10 hours, then the excess solution is separated by decantation. After that, the catalyst is dried in an electric cabinet. The drying mode is as follows: 60 ° C - 2 hours, 80 ° C - 2 hours, 110 ° C - 2 hours.

Before the process, the catalyst sample is activated in a stream of hydrogen (v = 3000 h ^-1 ) at a temperature of 450 ° C for 3 hours. Cyclization is carried out in a tubular reactor with a stationary catalyst bed at a pressure of 2 MPa, a molar ratio of hydrogen to feed 6: 1 and a space velocity of 2 h ^-1 in the temperature range 340-550 ° C.

The efficiency of the catalyst was estimated by the yield and content of aromatic hydrocarbons in the products obtained during the aromatization of normal paraffin hydrocarbons by passing a hydrogen-containing gas and a model feed - n-alkane with a molar ratio of hydrogen to feed from 1: 1 to 10: 1 through a fixed catalyst bed, loaded into the tubular reactor. Before the process, the catalyst sample is activated in a stream of hydrogen (v = 3000 h ^-1 ) at a temperature of 450 ° C for 3 hours. The tests were carried out at a space velocity of 0.5-4 h ^-1 in the temperature range 340-550 ° C under pressure 0.1-4.0 MPa. As model raw materials, n-hexane or n-octane was used.

The performance of the aromatization process of n-hexane and n-octane, carried out using samples of the catalysts corresponding to the invention, are presented in the table.

Claims (2)

1. The aromatization catalyst of synthetic normal liquid paraffin hydrocarbons containing a carrier of a porous zeolite and a binder, a catalytically active substance - platinum, characterized in that the carrier additionally contains gallium oxide nanopowder, as a binder - gibbsite powder with a particle size of not more than 40 microns, and as zeolite - zeolite KL with a particle size of not more than 0.10 mm, and the ratio of ingredients is in the following ranges, wt.%:
Platinum 0.3-0.8 Gibbsit 16-60 Zeolite KL 39.12-83.68 Gallium oxide 0.02-0.08 2. A method for producing an aromatization catalyst for synthetic normal liquid paraffin hydrocarbons according to claim 1, comprising preparing a granular carrier based on a porous zeolite and a binder, applying platinum from an aqueous solution to the carrier by cation exchange and drying, characterized in that the carrier further comprises gallium oxide nanopowder , gibbsite powder with a particle size of not more than 40 microns is used as a binder, and KL zeolite with a particle size of not more than 0.10 mm is used as a zeolite, the carrier is prepared by sequentially mixing KL zeolite powder, gallium oxide nanopowder and gibbsite powder, the mixture is moistened and peptized with a 5-15% nitric acid solution, mixing until a homogeneous mass is granulated by extrusion, the granules obtained are dried and calcined, and platinum is applied from an aqueous solution platinum tetraammonia with a concentration of platinum of 1.5-5.0 mg / ml