RU2405626C1 - Method of preparing bead cracking catalyst - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: present invention relates to oil refining, particularly to a method of preparing a bead platinum and zeolite-containing catalyst for cracking oil fractions. Described is a method of preparing the catalyst, involving mixing an aqueous suspension of zeolite Y with a suspension of alumina, sodium silicate solution with modulus-molar ratio SiO₂/Na₂O equal to 2.2-3.0, aluminium sulphate solution and chloroplatinic acid solution; moulding catalyst granules in a column with mineral oil; successive activation, first with a mixture of sodium sulphate and aluminium sulphate solutions with concentration of the latter equal to 0.1-4 g/dm³, then with aluminium sulphate solution with concentration of 4-10 g/dm³, and then with a solution of a mixture of nitrates of rare-earth elements; washing; drying and calcination of the granules in an atmosphere of flue gases and water vapour.

EFFECT: higher activity and apparent density of the catalyst.

1 tbl, 4 ex

Description

The invention relates to oil refining, in particular to methods for producing ball-type platinum-zeolite cracking catalysts.

The use of ball catalysts with increased bulk density can significantly increase the efficiency of industrial cracking plants of the Thermofor type, which is made possible by increasing the contact time of the feedstock with the catalyst. In practice, the operation of Thermofor-type plants with a weighted ball catalyst can significantly increase the processing capacity of raw materials, increase the yield of light oil products, and increase their quality.

To date, there are many ways to obtain ball cracking catalysts based on the formation of hydrogel granules in mineral oil obtained by mixing aqueous suspensions of zeolite, filler, with sodium silicate and aluminum sulfate solutions, processing the obtained hydrogel balls in salt solutions, drying and calcining. They can be classified according to the nature of the introduced zeolite and filler, molding characteristics, activation method, as well as drying and calcination conditions. In this case, the quality of the resulting product is primarily influenced by the features of the stages of processing hydrogel beads with aqueous solutions of salts, and the bulk density of the catalyst is controlled by changing the concentration of the filler.

In the first group of methods for producing ball cracking catalysts, we can distinguish those that include ion exchange in aqueous solutions of ammonium salts and rare earth elements in order to remove sodium cations and, thus, obtain an active and selective catalyst that, despite the presence of a filler, has a low bulk density .

The known composition and method of production of a catalyst for the conversion of hydrocarbons [US Pat. US No. 3312615], containing crystalline aluminosilicate (zeolite Y), an aluminosilicate matrix and inert fillers, in which a zeolite in the rare-earth cationic form in an amount of 2-15 wt.% Is mixed with 10-45 vol.% Finely ground alumina containing α-Al ₂ O ₃ more than 95 wt.% With a particle size of 0.1-3.0 μm - 100 wt.%, And introduced into an amorphous aluminosilicate matrix (50-75 vol.%) In the process of forming balls in an oil bath; hydrogel beads are subjected to activation with a solution of ammonium sulfate; washed from salts; dried in air and calcined in an atmosphere of water vapor. The disadvantages of this method are the low bulk density, mechanical strength and activity of the catalyst.

A known method of producing a ball catalyst for cracking oil fractions [US Pat. RF No. 2221644] by mixing solutions of sodium silicate, aluminum sulfate, suspensions of a NaY type zeolite and alumina with a particle size of less than 20 microns — 100 wt.%, Less than 10 microns — not less than 95 wt.%, Less than 4 microns — not less than 40 wt. .%; molding hydrogel granules in an oil column; subsequent activation with a solution of ammonium sulfate or nitrate and an aqueous solution of a mixture of rare earth nitrates; drying and calcining in an atmosphere of water vapor with a water vapor content of 18-30 vol.%. The disadvantages of this method are the low mechanical strength and activity of the catalyst. In addition, the bulk density of the catalyst obtained by the specified technical solution is not high enough.

The second group of methods for producing ball cracking catalysts is based on the use of solutions of activation of aluminum salts and rare earth elements. In this case, aluminum cations are used not only to remove sodium cations, but also to densify the structure of hydrogel beads and, thus, to obtain a catalyst having a relatively high bulk density, with increased activity and strength.

So, for example, a known method of producing a ball zeolite-containing catalyst for cracking of oil fractions [US Pat. RF No. 2221645], including mixing an aqueous suspension of zeolite Y in ammonium or rare-earth-ammonium cationic form with a sodium silicate solution containing an aqueous suspension of alumina having in its composition α-Al ₂ O ₃ not more than 85 wt.% And θ-Al ₂ O ₃ 10-20 wt.%, And a solution of aluminum sulfate; molding catalyst pellets in a mineral oil column; successive activation with a solution of aluminum sulfate and a mixture of rare earth nitrates; salt washing; drying and calcining in an atmosphere of flue gases and water vapor. The disadvantage of this method of obtaining is, despite the high bulk density, low mechanical strength of the catalyst at a high concentration of filler, which makes it difficult to use it in industrial plants. On the other hand, at a moderate or low concentration of filler, significant cracking of the catalyst balls after drying is observed, which increases the scrap volume and increases the cost of the product. In addition, the activity of the resulting catalyst is relatively low.

In the third group of methods for producing cracking catalysts, one can add those that additionally include, in the first stage, processing in sodium sulfate solution (syneresis) in order to regulate the structure of hydrogel beads.

A known method of producing a ball catalyst for cracking petroleum feeds [US Pat. RF No. 2229933], including the mixing of aqueous solutions of aluminum sulfate, sodium silicate and a suspension of NaY zeolite with a module of 4.5-9.5 with the formation of aluminosilicate zeolite-containing hydrosol, which further coagulates into a ball-shaped hydrogel in a layer of mineral oil with a density of 900-910 kg / cm ³ and viscosity 25-50 mm ² / s at 50 ° C; syneresis in a solution of sodium sulfate; activation with a solution of ammonium nitrate or sulfate; rare earth nitrate solution activation; washing, drying and calcining in a stream of steam-air mixture with a water vapor content of 18-30 vol.%. Obtained according to this method, the catalyst has, despite increased activity, low bulk density and low strength.

A known method of producing a zeolite-containing catalyst [A.S. USSR No. 389829] for the conversion of hydrocarbons by introducing 15 wt.% Zeolite NaY into 85 wt.% Aluminosilicon containing SiO ₂ - 93 wt.%, Al ₂ O ₃ - 7 wt.%, During molding; subsequent activation sequentially with sodium sulfate solutions; a basic salt of aluminum sulfate; condensate flushing; treatment with a solution of a mixture of rare earth nitrates and final washing with condensate; drying and calcining in an atmosphere of flue gases and water vapor. The disadvantages of this method include insufficient indicators of bulk density, strength and activity of the catalyst. In addition, there is significant cracking of the balls during production and operation.

A known method of producing a ball catalyst for cracking oil fractions [US Pat. RF No. 2285562] by mixing solutions of sodium silicate, aluminum sulfate and suspensions of zeolite NaY and alumina, the introduction of platinum chloride; molding hydrogel granules in an oil column; treatment with a solution of sodium sulfate and subsequent activation sequentially with a solution of ammonium sulfate or nitrate, a solution of aluminum sulfate with a concentration of 0.5-7 g / dm ³ and a mixture of rare earth nitrates; drying and calcining in an atmosphere of water vapor with a water vapor content of more than 40 vol.%. The disadvantages of this method of producing a catalyst are multi-stage production, as well as significant cracking of the catalyst balls during drying and insufficiently high activity during operation.

The closest in technical essence and the achieved effect to the proposed method is a method for producing a ball catalyst for cracking oil fractions [US Pat. RF No. 2287370], including mixing an aqueous suspension of zeolite Y in hydrogen or hydrogen-rare-earth form with a suspension of alumina in an amount of 3-65 wt.% (Counting on a calcined catalyst) containing α-Al ₂ O ₃ not more than 85 wt.% And θ-Al ₂ O ₃ 10-20 wt.% and having a particle size of less than 10 microns - 90-100 wt.%, less than 5 microns - 40-80 wt.%, in an aqueous solution of sodium silicate and a solution of aluminum sulfate, with the addition of platinum hydrochloric acid in a solution of aluminum sulfate or in an aqueous suspension of zeolite fed to the molding; molding catalyst pellets in a mineral oil column; successive activation with solutions of aluminum sulfate and a mixture of rare earth nitrates; washing from salts with condensate water; drying and calcining in an atmosphere of flue gases and water vapor. The resulting catalyst has a high bulk density. However, the disadvantage of the industrial production of the catalyst by this method is the significant cracking of the catalyst balls at the drying stage (cracking marriage), which is caused by the accumulation of defects inside the hydrogel balls due to their excessive uncontrolled compaction at the stage of activation with aluminum sulfate solution. This leads to a significant reduction in catalyst production and an increase in its cost.

The aim of the proposed technical solution is to obtain a highly active catalyst with increased bulk density while reducing production losses.

This goal is achieved by a method of producing a ball-type platinum-zeolite-containing cracking catalyst for petroleum fractions, comprising mixing an aqueous suspension of zeolite Y with a suspension of alumina, a solution of sodium silicate, a solution of aluminum sulfate and a solution of platinum chloride, forming granules of the catalyst in a column with mineral oil, successive activations with a solution of aluminum sulfate and a solution mixtures of rare earth nitrates, washing, drying and calcining granules in a flue gas atmosphere and water vapor, characterized in that for the preparation of the catalyst using sodium silicate with a module (molar ratio of SiO ₂ / Na ₂ O) of 2.2-3.0, and before activation in a solution of aluminum sulfate, a solution of a mixture of sodium sulfate and aluminum sulfate with the concentration of the latter is 0.1-4 g / dm ³ , while the concentration of aluminum sulfate in the activating solution is 4-10 g / dm ³ .

Distinctive features of the proposed method for producing a ball-type platinum-zeolite-containing cracking catalyst for oil fractions, comprising mixing an aqueous suspension of zeolite Y with a suspension of alumina, a solution of sodium silicate, a solution of aluminum sulfate and a solution of platinum chloride, forming granules of the catalyst in a column with mineral oil, processing with a solution of aluminum sulfate and a solution of nitrates rare earth elements, is the use of sodium silicate with a module of 2.2-3.0, as well as processing before tivatsiey solution of aluminum sulfate solution of a mixture of sodium sulfate and aluminum sulfate with the concentration of the latter 0.1-4 g / dm ^3, the concentration of aluminum sulfate in the activating solution is 4-10 g / dm ^3.

To regulate bulk density, the proposed method for the first time includes an approach based on changing the module used in the molding of water glass. Reducing the module from 3.0 to 2.2 can significantly increase the bulk density of the catalyst and, in addition, increase its activity.

In addition, the proposed method for the first time includes the stages of syneresis and coagulation under mild conditions of a solution of a mixture of sodium sulfate and aluminum sulfate. The separation of the treatment with a solution of aluminum sulfate in two stages - soft with a concentration of 0.1-4 g / dm ³ mixed with sodium sulfate, then hard with a concentration of 4-10 g / dm ³ - minimizes cracking of the catalyst granules at the drying stage, thereby reducing the most marriage rates.

Thus, the proposed technical solution has the signs of "novelty" and "significant differences".

Below are examples of the implementation of the proposed technical solution, with which it is illustrated, but not exhausted. The preparation conditions, as well as the properties of the catalysts according to the examples are presented in table 1.

1 Synthesis of catalysts

1.1 Raw materials

A solution of aluminum sulfate with a concentration of 80 g / DM ³ .

Solutions of sodium silicate with a concentration of 2.20-2.30 mol / dm ³ , modulus (molar ratio SiO ₂ / Na ₂ O) of 2.1-3.1.

Zeolites Y with a particle size of up to 10 microns more than 95 wt.%:

- in hydrogen form (HY) with a sodium oxide content of 2.1-3.0 wt.%, a crystallinity of 92-95% and a molar ratio of SiO ₂ / Al ₂ O _{3 of} 7.1 and 9.0;

- in a hydrogen-rare-earth form (Re / HY) with a sodium oxide content of 1.2 wt.%, rare earth oxides of 0.3 wt.%, a crystallinity of 90% and a molar ratio of SiO ₂ / Al ₂ O ₃ = 15.0 .

Platinum hydrochloric acid.

The filler is aluminum oxide with an α-Al ₂ O ₃ content of at least 85 wt.% And a particle size of up to 10 microns more than 95 wt.%.

Suspension stabilizers: sodium lignin sulfonate; sodium polyacrylate.

Chemically purified water.

A solution of sodium sulfate with a concentration of 20 g / DM ³ .

A solution of rare earth nitrates (REE) with a concentration of the sum of REE (in terms of oxides) 2 g / DM ³ .

1.2 Preparation of raw materials

To prepare zeolite suspensions, the calculated amount of zeolite is added to the heated water and mixed; if necessary, a stabilizer (sodium lignin sulfonate) is added to the zeolite suspension and processed on a disintegrator to grind the particles. The resulting suspension is diluted to a zeolite concentration of 100-120 g / dm ³ and the calculated amount of a solution of platinum chloride is added.

Preparation of a suspension of alumina involves mixing in water containing a stabilizer (sodium polyacrylate), the calculated amount of alumina powder - to a concentration of 250 g / dm ³ .

1.3 Formation of catalysts

The molding is based on mixing a pre-prepared silicate mixture (first stream) with a solution of aluminum sulfate (second stream). To prepare a silicate mixture in a mixer pre-mixed solutions of water glass, aqueous suspensions of zeolite and alumina. Cooled to a temperature of 3-8 ° C, the silicate mixture and the aluminum sulfate solution are mixed and fed to the distribution cone of the molding column, from which drops of sol flow into the mineral oil, forming hydrogel balls.

The streams are mixed in the ratio necessary to obtain a catalyst containing 10-12 wt.% Zeolite and 20-25 wt.% Filler.

1.4 Wet operations

The obtained hydrogel beads are subsequently subjected to the following treatments (wet operations):

1 Processing in a mixture of solutions of sodium sulfate and aluminum sulfate. In this case, the simultaneous occurrence of the processes of syneresis (compression of the hydrogel with the release of intermicellar fluid) and soft compaction of the hydrogel beads under the influence of aluminum salts. At this stage, a structure is laid in the hydrogel ball that provides high mechanical strength, minimal destruction of the catalyst during dehydration during drying and calcination. The treatment is carried out at a temperature of 30-40 ° C for 4-8 hours at a concentration of sodium sulfate 7 g / DM ³ , the values of the concentration of aluminum sulfate are shown in table 1.

2 Processing in a solution of aluminum sulfate for 12-24 hours, which ensures the removal of sodium cations from the aluminosilicate matrix and further, more rigid compaction of the hydrogel balls, which allows you to control the bulk weight of the commercial catalyst. The concentrations of aluminum sulfate used are shown in table 1.

3 Processing in a solution of nitrates of rare-earth elements (REE) with a concentration of REE oxides of 2 g / dm ³ for 12 h, while sodium and partially aluminum cations are removed from the zeolite and matrix and replaced by REE cations, which improves the selectivity of the catalyst.

4 Rinsing the balls with water for 8 hours to remove excess water-soluble salts (sodium sulfate, sodium nitrate, aluminum sulfate).

1.5 Drying the catalyst

Drying of the catalyst is carried out at a temperature of 160-170 ° C in a vapor-air atmosphere with steam pressure control, which reduces the risk of cracking of balls due to an increase in water vapor pressure during heating.

1.6 Calcination of the catalyst

After drying, the catalyst is calcined at a temperature of 680-770 ° C for 68-72 hours in an atmosphere of flue gases and water vapor.

1.7 Catalyst Testing

The catalyst is analyzed for the following indicators:

- cracking marriage, wt.% (mass fraction of balls cracked after drying);

- bulk weight, kg / m ³ ;

- strength under shock abrasion, wear 50 wt.%, s;

- activity according to the conversion, wt.%, yield, wt.%, and octane number according to the research method (MI) of the gasoline fraction (bp - 200 ° C) when cracking vacuum gas oil (with a boiling point of 510 ° C, density 910 kg / m ³ ) at a temperature of 460 ° C, a volumetric feed rate of 1.75 h ^-1 .

Example I illustrates a method for producing catalysts according to this technical solution. At the same time, liquid glass solution with a module (molar ratio of SiO ₂ / Al ₂ O ₃ ) of 2.2-3.0, as well as zeolites Y in hydrogen or hydrogen-rare-earth forms with a molar ratio of SiO ₂ / Al ₂ O, are used for their preparation ₃ 7.1-15.0. The observed defect cracking of the resulting catalysts is relatively low and amounts to 15-23 wt.%. The bulk density of the catalysts is relatively high (from 803 to 889 kg / m ³ ) and is regulated by the modulus of liquid glass used in the molding, as well as by the concentration of aluminum sulfate at the 1st and 2nd stages of wet operations. The catalysts have high strength (50 wt.% Wear for 800-900 s) and activity, which allows to obtain a gasoline fraction having an octane number according to the research method 88.5-92.3, with a yield of 36-42 wt.%.

Example II illustrates the deterioration of the characteristics of the obtained catalyst when used for its preparation of sodium silicate with a module whose values are outside the scope of the proposed technical solution. The use of sodium silicate with a molar ratio of Na ₂ O / Al ₂ O _{3 of} 2.1 leads to a decrease in the activity of the catalyst, and with a module of 3.1 it leads to an increase in rejects by cracking to 35 wt.% And a decrease in bulk density to 770 kg / m ³ .

Example III shows that the absence of aluminum sulfate in a solution of sodium sulfate or a change in its concentration to values outside the range of the proposed technical solution leads to an increase in rejects for cracking or a decrease in the activity of the catalyst.

According to example IV, the absence of the first stage of treatment with a mixture of sodium sulfates and aluminum leads to an increase in reject cracking to 62 wt.%. On the other hand, treating the balls with either a solution of a mixture of sodium and aluminum sulfates, or a solution of only sodium sulfate leads to a significant reduction in bulk density, strength and activity of the resulting catalyst. Finally, in the absence of both treatments, a large cracking marriage is observed, and the resulting catalyst has low activity, strength and bulk density.

Thus, mixing an aqueous suspension of zeolite Y with a suspension of alumina, a solution of sodium silicate with a module (molar ratio of SiO ₂ / Na ₂ O) of 2.2-3.0, a solution of aluminum sulfate and a solution of platinum chloride, forming pellets of the catalyst in a column with mineral oil, successive activations with a solution of a mixture of sodium sulfate and aluminum sulfate with a concentration of the latter 0.1-4 g / dm ³ , a solution of aluminum sulfate with a concentration of 4-10 g / dm ³ and a solution of a mixture of rare earth nitrates, washing, drying and calcination of gra Zero in the atmosphere of flue gases and water vapor make it possible to obtain, with reduced losses in production, a ball-type platinum-zeolite-containing catalyst for cracking oil fractions with high activity and increased bulk density.

Claims (1)

A method of producing a ball cracker for cracking petroleum fractions, comprising mixing an aqueous suspension of zeolite Y with a suspension of alumina, a solution of sodium silicate, a solution of aluminum sulfate and a solution of platinum chloride, forming granules of the catalyst in a column with mineral oil, sequential activation of a solution of aluminum sulfate and a solution of a mixture of rare earth elements , washing, drying and calcining the granules in an atmosphere of flue gases and water vapor, characterized in that for the preparation of kata a lysator, sodium silicate with a module-molar ratio of SiO ₂ / Na ₂ O of 2.2-3.0 is used, and before activation in a solution of aluminum sulfate, a solution of a mixture of sodium sulfate and aluminum sulfate with a concentration of the latter 0.1-4 g / dm is carried out ³ , while the concentration of aluminum sulfate in the activating solution is 4-10 g / DM ³ .