RU2430955C1 - Procedure for production of motor fuel - Google Patents

Abstract

FIELD: oil and gas production.

SUBSTANCE: invention refers to procedure for production of motor fuel by oil fraction cracking at presence of ball alumo-silicate platinum-zeolite-containing catalyst obtained by forming hydro-gel in mineral oil, synthesised mixing solutions of sodium silicate and aluminium sulphate with water suspensions of fine dispersed powders of zeolite of type Y and filler - aluminium oxide with contents α-Al₂O₃ not over 85 wt %, stabilised dispersers and containing platinum-hydrochloric acid, by activation, washing, drying and baking in atmosphere of water steam. The distinguished feature of the procedure is like follows: for preparation of catalyst there is used ultra-stable zeolite Y in hydrogen or hydrogen-rare earth form - at degree of crystallinity as high, as 85%, mole ratio SiO₂/Al₂O₃=10÷15. The degree of exchange to cations of rare earth elements of ultra-stable zeolite Y in hydrogen-rare earth form is not more, than 60%. Preliminary raw stock of catalytic cracking is hydro-fined to contents of sulphur not over 0.3 % wt. Catalytic cracking is performed with extraction of fractions of motor fuel and heavy fraction of product of catalytic cracking with temperature of beginning of boiling point above 360°C which is directed to re-cycle into source raw stock to ensure content as high, as 5 % wt.

EFFECT: increased output of benzene fraction and its octane number.

1 tbl

Description

The invention relates to oil refining, in particular to the production of motor fuels by catalytic cracking of petroleum fractions in plants with a moving bed of a molded catalyst, in particular by cracking heavy petroleum feeds on ball aluminosilicate platinum-zeolite-containing catalysts.

Previously known methods for producing motor fuels by cracking oil fractions aim to increase the yields of both the gasoline fraction and the amount of light oil products (gasoline and diesel fraction). At the same time, only a little attention is paid to the quality issues of the obtained gasoline fraction, in particular, detonation resistance.

To increase the yield and octane number of the gasoline fraction obtained in the cracking process, two approaches are used:

- increase in catalyst activity;

- optimization of process conditions.

The first group of approaches is based on introducing a zeolite component of various nature into the composition of the catalyst, increasing the activity of the matrix, and also making the catalyst heavier by introducing various fillers into its composition.

For example, there is a known method for producing motor fuels by cracking oil fractions using a zeolite-containing aluminosilicate catalyst in ball and microspherical forms [Cracking of oil fractions on zeolite-containing catalysts. Ed. S.N. Khadzhieva. M., Chemistry, 1982]. In ball form, the catalyst contains 10-12 wt.% Zeolite Y and has a chemical composition, wt.%:

aluminium oxide 9-10 rare earth oxides 2.0-2.5 sodium oxide 0.2-0.6 silica rest

In microspherical form, the catalyst contains 16-18 wt.% Zeolite Y and has the following chemical composition, wt.%:

aluminium oxide 10-12 rare earth oxides 2.5-3.0 sodium oxide 0.2-0.6 silica rest

The introduction of zeolite can significantly increase the activity of the catalyst. Nevertheless, the disadvantage of this method is the relatively low yields of light oil products, as well as the gasoline fraction, which is probably due to the moderate activity of the zeolite used in the preparation of the catalyst.

For the same reason, other known methods of producing motor fuels by cracking petroleum feeds based on the use of zeolite-containing aluminosilicate catalysts [Yandieva L.A., Zakarina N.A. Cracking catalysts and zeolites. Sat scientific works of the GrozNII, Moscow, TsNIITEneftekhim, 1984, No. 38, p. 76-80; US Pat. USA. No. 4429053, US Pat. France No. 2500006], they do not allow to obtain a gasoline fraction with a high yield, which would have a high octane number.

A known method of producing motor fuels by cracking oil fractions in the presence of a platinum zeolite-containing rare-earth aluminosilicate catalyst with a platinum content of 0.00001-0.002 wt.% [US Pat. France No. 2407745]. The content of zeolite treated with a metal salt of group II-VIII is 12-60 wt.%; the catalyst also possibly contains up to 75 wt.% clay, 20-50 wt.% α-Al ₂ O ₃ and an inorganic binder. The disadvantages of this method are the low yield of gasoline, as well as the increased consumption of catalyst during operation, which is caused by the low activity and low mechanical strength of the matrix used.

A known method of producing motor fuels by cracking petroleum fractions in the presence of a platinum zeolite-containing rare-earth aluminosilicate catalyst, consisting of 5-20 wt.% Zeolite Y with a molar ratio of SiO ₂ / Al ₂ O ₃ (module) of 4.5-7.0 and 100% degree crystallinity obtained by direct synthesis, and 80-95 wt.% aluminosilicate base [US Pat. RF №2229498]. The catalyst has a chemical composition, wt.%:

aluminium oxide 5.5-10.0 rare earth oxides 0.5-4.0 including: lanthanum oxide 0.45-3.2 cerium oxide 0.005-0.8 platinum 0.0001-0.01 iron oxide 0.01-0.4 calcium oxide 0.01-0.5 magnesium oxide 0.01-0.5 sodium oxide 0.01-0.5 silica rest

The use of NaY zeolite with a module of 4.5-7.0 in the catalyst allowed to slightly increase the yield of light oil products. Nevertheless, this method achieves only a relatively small increase in the yield of the gasoline fraction, which has a low octane number. In addition, there is an increased consumption of catalyst during operation in industrial plants, which is associated with the presence of a large number of defects in the structure of its balls due to the coarse dispersion of NaY zeolite particles used for its preparation.

Known methods for producing motor fuels by catalytic cracking of petroleum fractions in the presence of a platinum zeolite-containing rare-earth aluminosilicate catalyst, which use a catalyst consisting of 5-20 wt.% Type Y zeolite with a molar ratio of SiO ₂ / Al ₂ O ₃ equal to 4.5-9 , 5, and 80-95 wt.% Aluminosilicate base containing, wt.% [US Pat. RF №2166529]:

aluminium oxide 5.5-9.5 rare earth oxides 0.5-3.0 platinum 0.0001-0.01 iron oxide 0.01-0.4 calcium oxide 0.01-0.5 sodium oxide 0.01-0.5 silica rest

or aluminosilicate base, consisting of 40-95 wt.% amorphous aluminosilicate and 5-60 wt.% clay and having a chemical composition, wt.% [US Pat. RF №2252242]:

aluminium oxide 4,5-40,0 rare earth oxides 0.5-4.0 platinum 0.0001-0.01 sodium oxide 0.01-0.5 silica rest

The catalysts according to the indicated technical solutions are obtained by molding in a mineral oil a hydrosol synthesized by mixing aqueous solutions of aluminum sulfate, sodium silicate, suspensions of type Y zeolite with a module of 4.5-9.5 and (if necessary) a filler, followed by activation with solutions of ammonium nitrate or ammonium sulfate and rare earth nitrates, by drying and calcining in a steam-air mixture. The introduction of zeolite Y with a module up to 9.5, as well as fillers, into the composition of the catalyst used significantly increased the yield of light oil products. However, the disadvantage of the above methods for producing motor fuels by cracking oil fractions on these catalysts is the low octane number of the obtained gasoline fraction.

A similar disadvantage is the catalysts obtained by US Pat. RF №2229933 and US Pat. RF №2221644. So, according to US Pat. RF №2229933 the preparation of a ball catalyst involves mixing aqueous solutions of aluminum sulfate, sodium silicate and a suspension of NaY zeolite with a module of 4.5-9.5 in the mixer with the formation of aluminosilicate zeolite-containing hydrosol, which then coagulates into a ball-shaped hydrogel in a layer of mineral oil with a density of 900 -910 kg / cm ³ and a viscosity of 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; flushing; drying and calcining in a stream of steam-air mixture with a water vapor content of 18-30 vol.%. A method of obtaining a ball catalyst for cracking oil fractions [US Pat. RF No. 2221644] is based on a mixture of 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.

Known methods for producing a ball zeolite-containing catalyst for cracking oil fractions, including mixing an aqueous suspension of zeolite Y in ammonium or rare-earth ammonium [US Pat. RF №2221645], in hydrogen or hydrogen-rare-earth [US Pat. RF №2287370] cationic form with a solution of sodium silicate, an aqueous suspension of alumina containing 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. In addition to the low octane number of the obtained gasoline fraction, the disadvantages of these catalysts are low mechanical strength, which makes their operation in industrial plants impossible.

The second group of methods for increasing the yields of light oil products, as well as for producing gasoline fractions with a high octane number, is based on tightening the operating modes of catalytic cracking units: increasing the temperature in the reactor; increasing the frequency of circulation of the catalyst; load optimization for processed raw materials, etc.

Unfortunately, these approaches, due to technical and structural features, cannot be implemented on Thermofor-type plants. An exception is methods based on the introduction of hydrocarbon additives into the processed raw materials.

In order to increase the yield and octane number of the gasoline fraction, a cracking process is proposed in the presence of 0.5-10 vol.% (For raw materials) of an aromatic concentrate - a debutanized fraction of by-products of the pyrolysis of ethane, propane or butane, boiling within 20-215 ° C and containing 3-30% alkenes and alkadienes, as well as 30-70% aromatic hydrocarbons [US Pat. US No. 3758400]. The disadvantage of this method is the inaccessibility of the aromatic concentrate used in large volumes in industrial production.

Other approaches based on the addition of heavy residual fractions to the processed raw materials were implemented on plants using a microspherical catalyst. So, for example, the process of catalytic cracking of heavy crude oil is known [US Pat. US No. 3775287], based on the cracking of a mixture of vacuum gas oil and residual fractions on zeolite catalysts. In this case, up to 25 vol.% (Preferably 15-21 vol.%) Of residual oil products with a boiling point above 560 ° C are added to the cracking feed. Also known is a method of cracking a mixture of straight-run distillate fractions and 15-30 vol.% Residual fractions in a system with elevator reactors on a zeolite-containing catalyst, which allows to increase the yield of gasoline and its octane number [US Pat. US No. 3785959]. A common disadvantage of these methods is the strong coking ability of the processed raw materials containing a relatively large amount of residual fractions, which leads to the impossibility of their implementation in Thermophore-type plants.

The closest in technical essence and the achieved effect solution is a method for producing motor fuels by cracking oil fractions [US Pat. RF No. 2233309], according to which the process is carried out on a ball catalyst, consisting of 5-20 wt.% Zeolite type Y with a molar ratio of SiO ₂ / Al ₂ O ₃ equal to 4.5 to 9.5, and 80-95 wt. % aluminosilicate base, consisting of 40-95 wt.% amorphous aluminosilicate and 5-60 wt.% aluminum oxide in the form of α-Al ₂ O ₃ not more than 85 wt.% and alumina in low temperature forms of 10-20 wt.% and having a chemical composition, wt.%:

aluminium oxide 15,5-62,5 rare earth oxides 0.5-4.0 platinum 0.0001-0.01 iron oxide 0.01-0.4 calcium oxide 0.01-0.5 sodium oxide 0.01-0.5 silica rest

The catalyst according to the invention is obtained according to the following scheme:

1) mixed aqueous solutions of aluminum sulfate, acidified with sulfuric acid, and sodium silicate (water glass) containing zeolite Y and aluminum oxide;

2) coagulate the hydrosol formed during mixing into a ball-shaped hydrogel in a layer of mineral oil;

3) the hydrogel beads are treated in salt solutions and washed with condensate water;

4) dried and calcined the catalyst balls in a vapor-air atmosphere.

The disadvantages of the method are the low octane number of the obtained gasoline fraction, as well as low indicators of bulk density and mechanical strength of the catalyst, leading to difficulties in its operation.

The aim of the proposed technical solution is to increase the yield of the gasoline fraction and its octane number.

This goal is achieved by a method of producing motor fuels by cracking petroleum fractions in the presence of a ball aluminosilicate platinum-zeolite-containing catalyst obtained by molding in a mineral oil a hydrosol synthesized by mixing solutions of sodium silicate and aluminum sulfate with aqueous suspensions of fine powders of type Y zeolite in a hydrogen-rare-earth stabilized form and a filler, dispersants and containing platinum chloride acid, activation, washing, drying and roasting in an atmosphere of flue gases and water vapor, characterized in that ultra-stable zeolite Y in a hydrogen-rare-earth form is used for the preparation of the catalyst — with a crystallinity of at least 85%, a molar ratio of SiO ₂ / Al ₂ O ₃ = 10-15, and the degree of exchange on rare earth cations of not more than 60%; at the same time, the catalytic cracking feedstock is hydrofined before the sulfur content is not more than 0.3 wt.%, and the heavy fraction of the catalytic cracking product with a boiling point above 360 ° C is fed to the risel in the feedstock to a content of not more than 5 wt.%.

A distinctive feature of the proposed method for producing motor fuels is the cracking of oil fractions in the presence of a ball aluminosilicate platinum-zeolite-containing catalyst containing ultrastable zeolite Y in hydrogen-rare-earth form with a crystallinity of at least 85%, molar ratio SiO ₂ / Al ₂ O ₃ = 10-15, the degree of exchange for cations of rare earth elements is not more than 60%; at the same time, the catalytic cracking feedstock is hydrofined before the sulfur content is not more than 0.3 wt.%, and the heavy fraction of the catalytic cracking product with a boiling point above 360 ° C is fed to the risel in the feedstock to a content of not more than 5 wt.%.

In the above methods for producing ball cracking catalysts, type Y zeolite is added to the catalyst at the inactive sodium form molding step, NaY. Further conversion of NaY zeolite into an active form with the replacement of sodium cations by ammonium cations and rare earth elements is carried out already as part of hydrogel balls during wet operations - treatment with solutions of ammonium salts and rare earth elements, which, on the one hand, makes it difficult to control the quality of zeolite in the composition of the catalyst and, on the other hand, it complicates and greatly increases the cost of production.

The introduction of zeolite in the activated form into the composition of the ball catalyst allows one to switch to a higher level of regulation and quality control of the catalyst.

Known methods of activating zeolite NaY, including the conversion to ultra-stable form [for example, N. S. Kozlov, I. I. Urbanovich, M. F. Rusak “Ultra-stable zeolites”, Minsk, “Science and Technology”, 1979], allowing widely vary the main quality indicators of zeolite: crystallinity, molar ratio of SiO ₂ / Al ₂ O ₃ in the structure, the degree of exchange of sodium cations for hydrogen and rare earth elements. In this case, the task of catalyst synthesis is to optimize the properties of the activated ultra-stable zeolite used in combination with the synthesis conditions as a whole.

A high modulus, a degree of crystallinity of at least 85%, and an exchange rate for cations of rare earth elements of not more than 60% of the hydrogen-rare-earth form of ultra-stable zeolite Y are necessary to obtain a catalyst capable of providing a high yield and octane number of the gasoline fraction.

Preliminary hydrofining of catalytic cracking raw materials to a sulfur content of not more than 0.3 wt.% Allows to increase the octane number of the obtained gasoline fraction. In addition, the lower coking ability of the feedstock with a sulfur content of not more than 0.3 wt.% Allows feeding part of the catalytic cracking product fraction with a boiling point above 360 ° C per risicle to the feed stream in order to increase the octane number of the gasoline produced.

Analysis of the totality of the above techniques allows us to conclude that the claimed technical solution meets the criteria 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 characteristics of the catalysts, the conditions for their preparation, as well as the conditions and performance of the process are presented in the table.

1. Synthesis of catalysts

1.1. Raw materials

Solutions of aluminum sulfate with a concentration of 0.1-80 g / DM ³ .

A solution of water glass with a concentration of 2.20-2.30 mol / dm ³ , the molar ratio of SiO ₂ / Na ₂ O = 2.9.

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

1. synthetic zeolite Na-Y with a molar ratio of SiO ₂ / Al ₂ O ₃ 5.5, crystallinity of 100%, sodium oxide content of 13.1 wt.%;

2. zeolite Y in hydrogen form (HY) with a molar ratio of SiO ₂ / Al ₂ O _{3 of} 5.8, a crystallinity of 98% and a content of sodium oxide of 1.5 wt.%;

3. ultrastable zeolites Y

- in hydrogen form (H-USY) with a molar ratio of SiO ₂ / Al ₂ O _{3 of} 10.0 and 13.2, a crystallinity of 85-95% and a content of sodium oxide of 2.1 wt.%,

- in a hydrogen-rare-earth form (Re / H-USY) with a molar ratio of SiO ₂ / Al ₂ O _{3 of} 15.0, a degree of crystallinity of 90%, a degree of exchange for cations of rare-earth elements (REE) of 45, 60 and 73%, with a content sodium oxide 1.2 wt.%.

Hydrochloric acid

The filler is alumina with an α-Al ₂ O ₃ content of not more than 85 wt.% And a particle size of up to 10 microns more than 95 wt.%.

Chemically purified water, water condensate.

Stabilizing dispersants (suspension stabilizers): sodium lignin sulfonate; sodium polyacrylate.

A solution of sodium sulfate with a concentration of 7 g / DM ³ .

A solution of ammonium sulfate with a concentration of 8-10 g / DM ³ .

A solution of rare earth nitrates with a concentration of the sum of REE (in terms of oxides) 1-3 g / DM ³ .

1.2. Raw material preparation

To prepare zeolite suspensions, the calculated amount of zeolite is added to the heated water and mixed; if necessary, a stabilizing dispersant (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 filler suspension (alumina) involves stirring in water containing a stabilizing dispersant (sodium polyacrylate), a calculated amount of alumina powder to a concentration of 100-250 g / dm ³ , and a calculated amount of a solution of platinum chloride.

1.3. Catalyst Forming

The molding is based on mixing a pre-prepared silicate mixture (first stream) with a solution of aluminum sulfate (second stream). To prepare the silicate mixture, liquid glass solutions, aqueous zeolite suspensions and alumina are pre-mixed in the mixer. 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 up to 30 wt.% Filler (alumina).

1.4. Wet operations

The obtained hydrogel beads are subjected to activation, one of three methods of sequential treatments (wet operations).

Method 1 includes sequential processing:

1. in a solution of sodium sulfate;

2. in a solution of a mixture of rare earth nitrates;

3. in a solution of ammonium sulfate;

4. flushing balls with water condensate.

Method 2 includes sequential processing:

1. in a solution of sodium sulfate;

2. in a solution of ammonium sulfate;

3. rinsing in chemically purified water;

4. in a solution of aluminum sulfate;

5. in a solution of a mixture of rare earth nitrates;

6. rinse with water condensate.

Method 3 includes sequential processing:

1. in a solution of sodium sulfate;

2. in a solution of aluminum sulfate;

3. in a solution of rare earth nitrates;

4. flushing balls with condensate.

1.5. Catalyst drying

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

1.6. Catalyst calcination

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

2. Catalytic tests

The activity of the obtained catalysts was determined in a pilot installation by the conversion of wt.%, As well as the yield of the gasoline fraction (n.c. - 200 ° C), wt.% And its octane number according to the research method (MI) when cracking vacuum gas oil (with temperature the end of boiling 510 ° C, density 910 kg / m ³ ) at temperatures 465-480 ° C, the volumetric feed rate of 1.75 h ^-1 . During the experiments, a heavy fraction of the catalytic cracking product was added to vacuum gas oil with a boiling point above 360 ° C to a content of 5.0 wt.%.

Example I (table) presents the essence of the proposed technical solution. Carrying out a cracking process with feeding to a risicl in hydrofined raw materials containing not more than 0.3 wt.% Sulfur, up to 5.0 wt.% Of a product fraction with a boiling point above 360 ° С on catalysts obtained by molding a synthesized hydrosol into mineral oil by mixing solutions of sodium silicate and aluminum sulfate with aqueous suspensions of ultrastable zeolite Y powders in a hydrogen-rare-earth form - with a crystallinity of at least 85%, a molar ratio of SiO ₂ / Al ₂ O ₃ = 10.0-15.0, a degree of exchange for cations rare earth ele ENTOV not more than 60% filler (alumina), processing according to the methods 1-3, drying and calcining, provides a gasoline fraction with a yield of 33-43 wt.%, having an octane number to 92.5 units (MI).

The use of raw materials with a sulfur content of 0.5 and 1.5 wt.% (Example II) leads to a slight decrease in the yield of the gasoline fraction and a decrease in its octane number to 88.3 and 84.3 units (MI), respectively.

Carrying out the process without supplying a heavy fraction to risicle in the raw material or at its content of 7.2 wt.% (Example III) leads to a decrease in the yield of cracked gasoline and a decrease in its octane number.

Carrying out the process on a catalyst including ultrastable zeolite Y in a hydrogen-rare-earth form with a degree of exchange for cations of rare-earth elements of 73% (Example IV) leads to a decrease in the octane number of the obtained gasoline fraction.

The use of zeolites Y in the hydrogen and sodium forms with a molar ratio of SiO ₂ / Al ₂ O _{3 of} 5.5-5.8 for the preparation of the catalyst for the catalyst leads to a decrease in the yield and octane number of the obtained gasoline fraction (example V).

A decrease in the degree of crystallinity of ultrastable Y zeolites used to prepare process catalysts leads to a decrease in the yield of the gasoline fraction and a slight decrease in the octane number (Example VI).

Claims (1)

A method of producing motor fuels by cracking petroleum fractions in the presence of a ball aluminosilicate platinum-zeolite-containing catalyst obtained by molding in a mineral oil a hydrogel synthesized by mixing solutions of sodium silicate and aluminum sulfate with aqueous suspensions of fine powders of type Y zeolite and filler aluminum oxide containing α-Al ₂ O ₃ not more than 85 wt.%, Stabilized dispersants and containing platinum chloride acid, activation, washing, drying and calcination in an atmosphere of water vapor, characterized in that ultra-stable zeolite Y in the hydrogen or hydrogen-rare-earth form is used for the preparation of the catalyst with a crystallinity of at least 85%, the molar ratio of SiO ₂ / Al ₂ O ₃ = 10 ÷ 15, and in the case of ultra-stable zeolite Y in the hydrogen-rare-earth form, the degree of exchange for cations of rare-earth elements is not more than 60%, while preliminary refinement of the catalytic cracking feed is carried out to a sulfur content of not more than 0.3 wt.%, Catalytic cracking is carried out with the formation of fractions of motor fuels and the heavy fraction of the catalytic cracking product with a boiling point above 360 ° С, which is fed to the risel in the feedstock to a content of not more than 5 wt.%.