RU2060819C1 - Process for preparing ball catalyst for reforming of gasoline fractions - Google Patents

Abstract

FIELD: oil refining. SUBSTANCE: preparation of ball catalyst for reforming of gasoline fractions is carried out by dissolving aluminum- containing reagent in aqueous solution of nitric acid or aluminium nitrate to form aluminium salt ash. The resulting ash is neutralized with aqueous ammonia solution till pH is adjusted to at least 11.0. The suspension is treated with solution of nitric acid or aluminium nitrate till nitric acid to aluminium molar ratio reaches 0.7-1.3. The resulting ash is evaporated to aluminium concentration of 110-140 g/l, molded in the form of drops in mold-forming liquid till drops are formed. Spherical granules of aluminium hydroxide are washed, dried and calcined. The resulting support is impregnated with active components, dried and calcined. The aluminium containing reagent is aluminium metal or mixture of aluminium with aluminium hydroxide. The mold- forming liquid is 6-30 % aqueous ammonia solution. EFFECT: more efficient preparation process. 3 cl, 1 tbl

Description

 The invention relates to oil refining, in particular to methods for preparing ball catalysts for reforming gasoline fractions.

 For the reforming process with continuous regeneration (moving bed) of the catalyst, only contacts with a granule shape close to the ideal spherical and fairly narrow size distribution of the spheres are suitable.

A known method of producing a reforming catalyst on granules of a carrier of active alumina of a ball form by the so-called method hydrocarbon-ammonia molding. This method consists in deep peptization of aluminum hydroxide with aqueous solutions of mineral or organic acids to obtain a pseudo sol and drip it into a hydrocarbon liquid (kerosene) and then into an ammonia solution and subsequent operations of aging (maturation) and heat treatment of carrier balls, deposition of active components (platinum, promoter metals and halogen) and catalyst heat treatment [1]
This method allows to obtain sufficiently strong spherical granules of reforming catalysts, however, it has some disadvantages, namely: a wide size distribution of balls; deviation of the shape of the granules from the spherical and rough surface of the balls; high bulk density of the catalyst, usually more than 0.64 g / cm ³ ; relatively low pore volume, not higher than 0.75 cm ³ / g.

 This leads to the fact that the selectivity and stability of the reforming catalysts obtained by this method under conditions of continuous regeneration are insufficient, and the abrasion and packaging damage of the layer of granules are unacceptably large.

Closest to the proposed method in technical essence is a method of preparing a ball catalyst for reforming gasoline fractions, in accordance with which metal aluminum is dissolved in an aqueous solution of hydrochloric acid or aluminum chloride to obtain a true sol of aluminum hydrochloride with a molar ratio of Cl: Al from 0.5 to 1,0 [2]
This sol is neutralized with an aqueous solution of a base, usually urotropine (hexamethylenetetramine), and then dispersed into a forming liquid in order to obtain spherical droplets. For this are advantageously used a hydrocarbon oil (such as industrial or turbine) with a high temperature (not lower than 90 ° ^C). The resulting spherical particles are subjected to long-term maturation in oil for 10-18 hours, and then aging in a weak solution of ammonia (4-7%) and, finally, washed with water from impurities, mainly from oil and ammonium chloride.

The obtained pellets were dried in air for several hours at a temperature of 100-120 ^C and then calcined at 550-630 ° ^C. It is essential that a high upper temperature limit of the calcining by the need to remove traces of oil from the carrier. Platinum, metals, promoters and halogen are applied onto the obtained carrier balls in a known manner [3]
The described method allows to obtain granules that are close in shape to ideal spheres, with a narrow size distribution, with a low bulk density (0.52-0.58 g / cm ³ ), high pore volume (0.8-0.9 cm ³ / g and more) and, as a result, with low abrasion in the process with a moving layer and with acceptable levels of activity and stability.

 However, the considered method has several disadvantages: the need to use hot hydrocarbon oil and urotropin, which complicates the main process chain and the technology for the disposal of wastewater; the use of hydrochloric acid, which leads to some corrosion problems and makes it difficult to implement the ammonium salt (chloride) obtained as a by-product; prolonged exposure in oil and ammonia, lengthy drying and calcining operations, which makes the technological scheme cumbersome and complicates the design process in a continuous mode; insufficient selectivity of the resulting catalysts in the reforming of gasoline fractions.

 The aim of the invention is to provide a method of preparing a ball catalyst for reforming gasoline fractions, which would improve the selectivity and stability of the catalyst, would reduce its abrasion during operation.

A method is proposed for preparing a ball catalyst for reforming gasoline fractions containing the active components platinum, halogen, a promoter on a carrier of active alumina by dissolving an aluminum-containing reagent in an aqueous solution of nitric acid or aluminum nitrate to form an aluminum hydroxide salt, and neutralizing the obtained sol with an aqueous ammonia solution until pH not less than 11.0, processing the resulting suspension with a solution of nitric acid or aluminum nitrate to achieve a molar ratio of NO ₃ : Al, equal to 0.7-1.3, followed by evaporation of the sol to an aluminum concentration of 110-140 g / l, drip molding of the sol in the forming fluid and ripening of spherical granules of aluminum hydroxide, washing, drying, calcining, impregnating the obtained support with active components, drying and calcining the catalyst. As an aluminum-containing reagent, metallic aluminum or a mixture of aluminum with aluminum hydroxide is used. As a forming fluid using a 6-30% aqueous solution of ammonia.

Significant distinguishing features of the proposed method is the use of nitric acid as a mineral acid, as an alkaline agent, aqueous ammonia solution, neutralization of the aluminum hydroxysalt sol to achieve a pH of at least 11.0, processing the resulting suspension with a solution of nitric acid or aluminum nitrate to achieve a molar ratio of NO ₃ : Al, equal to 0.7-1.3, followed by evaporation of the sol to an aluminum concentration of 110-140 g / l.

 Analysis of the known technical solutions in the field of production of a ball catalyst for reforming gasoline fractions allows us to conclude that they lack features similar to the essential distinguishing features of the proposed technical solution, that is, the technical solution meets the requirements of an inventive step.

The method is as follows. Aluminum metal or a mixture of aluminum with aluminum hydroxide is dissolved in a deficiency of nitric acid or a solution of aluminum nitrate to obtain a true sol of aluminum hydroxynitrate. This sol is neutralized with aqueous ammonia to a pH of not less than 11.0, nitric acid or aluminum nitrate is added to the resulting suspension, the molar ratio of NO ₃ : Al is adjusted to 0.7-1.3, and the resulting working sol is evaporated to an aluminum concentration of 110- 140 g / l

Working sol through a dispersing device is instilled into an aqueous solution of ammonia with a concentration of 6-30% where it is kept for 1 to 5 minutes. Then the beads were washed with water svezhesformovannye impurities from ammonium nitrate, dried carrier in the air at 100-150 ^{° C} and calcined at a temperature of 500-550 ^{° C} by passing air through a bed of beads-coolant. Then, platinum, halogen, promoters are applied to the carrier from a true solution in a known manner.

Excess water was removed by evaporation, and then the resultant catalyst was dried at 100-150 ^{° C} and calcined at 480-520 ^{° C} in a stream of dry air.

 The method can be used for the preparation of ball reforming catalysts having sulfur in their composition.

As a granulating agent, aqueous solutions of sulfur-containing mineral or organic acids and their ammonium salts are used. These include sulfuric acid, peroxosulfuric, supra sulfuric, peroxodisulfuric, sulfuric, thiosulfuric, sulfanesulfonic acids, thiosulfuric, polythionic acids of the type Н ₂ SхО ₆ (X = 3 to 6), dithionic acid, thioglycolic, sulfosalicylic acid, ammonium salts of the sulfate type ammonium, ammonium sulfite, ammonium bisulfate, and the like. For introducing sulfur into the carrier, granules of the latter are brought into contact with a sulfur-containing agent immediately before the operation of applying the active components.

Before operation or testing, the catalyst is reduced with electrolytic hydrogen or a hydrogen-containing gas, VSS (not less than 90% H ₂ ), under the following conditions: temperature 380-520 ^о С depending on the promoter, pressure 0.7 MPa, duration 4-6 h, speed filing H ₂ (WASH) of about 1000 vol. / 1 about. catalyst per hour.

Catalyst Tests carried out in a pilot plant in the hydrotreated gasoline fraction boiling in the range 85-180 ^{° C,} at a pressure of 0.8 MPa, a volumetric hourly space velocity of 1.5 h ^-1 and the circulation ratio WASH 1500 Nl / l cyrya.

 Moreover, the selectivity of the process is defined as the yield of stable (debutanized) catalysis with an octane number by the research method (IOI) equal to 105, and activity as the temperature required to produce gasoline with this IOI (the higher the temperature, the lower the activity).

To determine the stability of the feed rate is increased to 2.0 h ^-1, and the multiplicity of circulation WASH reduced to 1000, and the test was carried out at 515 ^{° C} (stringent conditions). Stability is expressed as a drop in activity (temperature increase) between the 20th and 100th hours of the test in hard mode.

 From the examples below and the table it can be seen that the catalysts obtained in accordance with the invention have lower abrasion (i.e., less percent loss of catalyst and platinum and lower specific consumption of catalyst) and higher selectivity, as well as stability, and, in addition are characterized by a more economical cooking technology, which is expressed in the rejection of the use of urotropin and oil, heating of the forming fluid, a sharp reduction in the duration of all operations, starting with the working sol, as well as simplification of the scrap scheme tion of wastewater.

PRI me R 1. Taken 52.9 g of aluminum metal (purity 99.985%), 129.8 g of a 60% solution of nitric acid (74.04 g HNO ₃ ) and 0.54 l of distilled water. Aluminum with continuous stirring and heating to boiling for 12 hours was dissolved in acid and a true sol of aluminum hydroxynitrate was obtained with a molar ratio of NO ₃ / Al of 0.5 and an aluminum concentration of 80 g / L. To the resulting sol, with a continuous stirring, a 20% solution of NH ₄ OH was added dropwise to a pH of 11.2. After stirring, the calculated amount of nitric acid solution (41.16 g of a 60% solution, or 24.7 g of HNO ₃ ) was added to the obtained intermediate sol, until the final molar ratio of NO ₃ / Al in the sol was 0.7.

 Then, by boiling from a sol, 330 ml of water was evaporated in such a way that the aluminum concentration in the final (working) ash became 110 g / l.

The resulting working sol was dispersed dropwise through a vibrating batcher into a column with a 20% solution of NH ₄ OH. The residence time of each drop (ball) in the forming ammonia was 3 min, after which the balls of aluminum hydroxide were washed with water on a suction filter from ammonium nitrate.

Washed the salt beads were dried in an oven at ¹²⁰ ° C in air and then calcined at 550 ^{° C} for 3 hours in a dry air stream (dew point not higher than minus 40 ° ^C), a flow rate of 50 l / h ( space velocity 1000 h ^-1 ).

The abradability of the calcined carrier balls, as determined by the standard method (in the I.F.Kh. mill), was 2%. A portion of the finished carrier balls, equal to 25.0 g in terms of Al ₂ O _3, was evacuated to a residual pressure of 20 mm Hg. and then brought into contact with 36 cm ^{3 of an} aqueous solution containing 0.19 g of H ₂ PtCl ₆ , 0.22 g of SnCl ₄ and 1.04 g of a 36% HCl solution. The catalyst and the impregnating solution is stirred for 1 h without external heating, whereupon the temperature was raised to ⁸⁰ ° C and the impregnation was continued at a temperature of ≥ 80 ° ^C for a further 1 hour and then excess water was evaporated until a state of flowability of catalyst.

The catalyst was dried at ¹¹⁰ ° C for 2 hours and then calcined at ⁵⁰⁰ ° C for 2 hours in a stream of dry air being passed through the bed of pellets at a rate of 25 l / h (500 h ^-1).

The composition of the obtained catalyst, wt. Pt 0.36; Sn 0.4; Cl 1.3; Al ₂ O _{3 the} rest.

The catalyst was reduced at 510 ^{° C,} and then tested according to the standard procedure described above.

The activity of the catalyst was 495 ^about With selectivity of 86 wt. stability of 16 units.

PRI me R 2. Taken 52.9 g of aluminum metal (purity 99.985%), 129.8 g of a 60% solution of nitric acid (74.04 g of HNO ₃ ) and 0.54 l of distilled water. Aluminum with continuous stirring and heating to boiling for 12 hours was dissolved in acid and a true aluminum hydroxynitrate sol with a molar ratio of NO ₃ / Al of 0.5 and an aluminum concentration of 80 g / L was obtained. To the resulting sol with continuous vigorous stirring was added dropwise a 20% solution of NH ₄ OH to a pH of 11.2. After stirring, a calculated amount of a nitric acid solution (41.16 g of a 60% solution, or 24.7 g of HNO ₃ ) was added to the obtained intermediate sol to achieve a final molar ratio of NO ₃ / Al in the sol of 0.7.

 Then, by boiling from a sol, 330 ml of water was evaporated so that the aluminum concentration in the final (working) ash became 110 g / l.

The resulting working sol was dispersed dropwise through a vibrating batcher into a column with a 20% solution of NH ₄ OH. The residence time of each drop (ball) in the forming ammonia was 3 min, after which the balls of aluminum hydroxide were washed with water on a suction filter from ammonium nitrate.

Washed the salt beads were dried in an oven at ¹²⁰ ° C in air and then calcined at 550 ^{° C} for 3 hours in a dry air stream (dew point not higher than minus 40 ° ^C), a flow rate of 50 l / h ( space velocity 1000 h ^-1 ).

The abrasion of the calcined carrier balls when determined by the standard method (in the IFC mill) was 2%
A portion of the finished carrier balls, equal to 25.0 g in terms of Al ₂ O ₃ , was evacuated to a residual pressure of 20 mm Hg. and then brought in contact with 24 cm ^{3 of a} solution of (NH ₄ ) ₂ SO ₄ with a concentration of 6.9 g / l. Then, 36 cm ^{3 of an} aqueous solution containing 0.19 g of H ₂ PtCl ₆ , 0.22 g of SnCl ₄ and 1.04 g of a 36% HCl solution were added to a carrier moistened with a solution of ammonium sulfate. The catalyst and the impregnating solution is stirred for 1 h without external heating, whereupon the temperature was raised to ⁸⁰ ° C and the impregnation was continued at a temperature of ≥ 80 ° ^C for a further 1 hour and then excess water was evaporated until a state of flowability of catalyst.

The catalyst was dried at ¹¹⁰ ° C for 2 hours and then calcined at ⁵⁰⁰ ° C for 2 hours in a stream of dry air being passed through the bed of pellets at a rate of 25 l / h (500 h ^-1).

The composition of the obtained catalyst, wt. Pt 0.36; Sn 0.4; Cl 1.3; SO ₄ 0.48; Al ₂ O _{3 the} rest.

The catalyst was reduced at 510 ^{° C,} and then tested according to the standard procedure described above.

The activity of the catalyst was 494 ^about With selectivity of 86.2 wt. stability of 14 units.

 PRI me R 3. The media is basically prepared in the same way as described in example 1, but with slight differences.

To prepare the sol, 52.9 g of aluminum metal, 148.08 g of a 60% solution of nitric acid (88.87 g of HNO ₃ ) and 0.48 l of distilled water were taken. A primary true sol of aluminum hydroxynitrate was obtained with a molar ratio of NO ₃ / Al of 0.6 and an aluminum concentration of 85 g / l. To it was added 39 ml of a 25% solution of NH ₄ OH to a pH of ≈ 11.1. Then, 144 ml of a 60% nitric acid solution (86.4 g of HNO ₃ ) was taken to the obtained intermediate sol. The final molar ratio of NO ₃ / Al was 1.3.

Upon boiling the intermediate sol, 410 ml of water was removed, and the final (working) concentration of aluminum became equal to 140 g / l. Balls were formed in a 6% solution of NH ₄ OH as a forming fluid, the residence time of the balls in the column was 5 minutes.

 After washing, the carrier balls were dried and calcined in exactly the same way as in Example 1.

The abrasion of the carrier balls was 3%
After evacuation, 25.0 g of the finished carrier was impregnated with 28 cm ³ of a sulfuric acid solution with a concentration of 3.18 g / l. The main impregnation was carried out by pouring 38 cm ^{3 of a} solution containing 0.14 g of H ₂ PtCl ₆ , 0.16 g of SnCl ₄ , 0.04 g of ZnCl ₂ and 0.7 cm ^{3 of a} 36% solution into a carrier moistened with sulfuric acid Hcl.

 Further operations were carried out identically to example 1.

The composition of the catalyst, wt. Pt 0.26; Sn 0.3; Zn 0.07; Cl 1.1; Al ₂ O _{3 the} rest.

The results of a standard test: activity 495 ^about With selectivity 86.3% stability of 16 units

PRI me R 4. The carrier was prepared mainly according to the technology described in example 1. In the preparation of the primary true Zola nitric acid was replaced by a solution of aluminum nitrate. Thus the dissolution of 52.9 g of aluminum was expended 460 cm ³ of solution Al (NO _{3) 3} c concentration of 150 g / l (69.5 g Al (NO _{3) 3).}

The molar ratio of NO ₃ / Al in the working ash is 1.0, the sol concentration is 120 g Al / L.

The molding was carried out in a 30% solution of NH ₄ OH, residence time 1 min.

The abrasion of the carrier balls was 2%
The catalyst was also prepared mainly according to Example 1. First, the support was moistened with a calculated amount of a solution of sulfosalicylic acid, and then impregnated with a solution containing a calculated amount of H ₂ PtCl ₆ , SnCl ₄ , HWO ₄ and Hcl.

The composition of the finished catalyst, wt. Pt 0.26; Sn 0.6; W 0.01; Cl 1.0; SO ₄ 0.35; Al ₂ O _{3 the} rest.

Temperature reduction catalyst 520 ^C.

The results of catalytic tests: activity 494 ^about With; selectivity 86.0 wt. stability of 16 units.

 PRI me R 5. The media is prepared analogously to example 1.

For dissolution, we took 35 g of aluminum metal and 45.7 g of finely crystalline pseudoboehmite hydroxide (PPP 26% Al ₂ O ₃ content _of 33.8% which corresponds to 17.9 g of Al). The ratio of NO ₃ / Al in the working ash is 1.0, the sol concentration is 120 g Al / L. The molding was carried out in a 20% solution of NH ₄ OH with a residence time of 2 minutes.

The abrasion of the calcined balls of the carrier was 3%
The introduction of sulfur was carried out from a solution of NH ₄ HSO ₄ .

The composition of the catalyst, wt. Pt 0.36; Re 0.36; Zn 0.05; SO ₄ 0.48; Cl 1.1; Al ₂ O _{3 the} rest.

The recovery of the catalyst was carried out at 450 ^about C.

Test results: activity 497 ^about C, selectivity 86.1 wt. stability of 15 units.

 PRI me R 6. The preparation of the media is performed in the same mode as in example 1. 317, 4 g of aluminum metal were taken for dissolution, and the quantities of all other reagents were also increased by 6 times.

The molar ratio of NO ₃ / Al in the working ash was 1.1, and the aluminum concentration was 120 g / l. The balls were formed in a 20% NH ₄ OH solution with a residence time of 1.5 minutes in the column.

The abrasion of the spheres of the carrier was equal to 2%
From a calcined support, 6 samples of 25.0 g each were taken to prepare the catalysts. The catalysts are designated as 6a, 6b, 6c, 6d, 6d and 6e. The following are successively reported: sulphurization agent, the amount of sulfur introduced, calculated as sulfate, the composition of the catalyst, wt. Temperature reduction of the catalyst, ^of C; activity, ^o C; selectivity, wt. and stability, units 6a (NH ₄ ) ₂ SO ₃ ; 0.40; Pt 0.36; Pd 0.1; Cl 1.2; 420; 494; 86.2; 15; 6b: H ₂ SO ₄ ; 0.48; Pt 0.36; Ir 0.05; Cd 0.1, Cl 1.1; 380; 495; 86.0; 15; 6c: (NH ₄ ) ₂ SO ₄ ; 0.46; Pt 0.36; Co 0.5; Zn 0.1; Cl 1.2; 450; 497; 86.0; 18; 6 g: thioglycolic acid, 0.3; Pt 0.26; Re 0.5; Ca 0.3; Cl 1.0; 480; 495; 86.1; 13; 6d: H ₂ S ₂ O ₈ ; 0.48; Pt 0.36; Sn 0.2; Mg 0.3; Cl 1.1; 450; 497; 86.2; 16; 6e: H ₂ SO ₄ ; 0.40; Pt 0.36; Re 0.2; Sn 0.2; Ba 0.1; Cl 1.2; 480; 494; 86.3; 18;
PRI me R 7 (according to the prototype [2]). 52.9 g of aluminum metal (99.985%), 123.1 g of a 36% hydrochloric acid solution (44.3 g of HCl) 0.24 l of distilled water were taken.

After dissolving for 15 hours at boiling temperature 102 ^{° C} obtained a true aluminum hydroxychloride sol having a molar Cl / Al 0,87 ratio and the concentration of 180 g Al / liter.

For further operations, 300 cm ^{3 of the} obtained sol was taken. To this portion was added 55 cm ^{3 of} water and 355 cm ³ of a urotropine solution with a concentration of 31.3% (333 kg / l). After stirring working sol with a height of about 3 cm through the dispenser was dispersed dropwise into the oil-20A with a temperature ^of 92-98 C. The concentrations of the components in the working sol reached, g / l: Al 77; urotropin 166; Cl 66.7. Svezhesformovannye beads were soaked in hot oil (92-98 ° ^C) for 16 hours during the 10 hours in a 4% solution of NH ₄ OH (84-86 ° ^C), after which they were washed first 0.1% - NH ₄ OH solution and finally water.

Carrier beads are dried in air in an oven at ¹²⁰ ° C for 8 hours and then calcined in a stream of dry air for 5 hours at a temperature of 630 ° ^C.

 The abrasion of the finished support was 6%. On the obtained support, in exact accordance with the regime of Example 1, a platinum-tin catalyst of the same composition was prepared.

The results of catalytic tests: activity 497 ^about With selectivity of 85.8 wt. stability of 21 units.

 The above examples and the table illustrate the higher performance of the catalysts prepared by the proposed method in comparison with the known, namely: lower abrasion, higher selectivity and stability.

Claims (3)

1. A method of preparing a ball catalyst for reforming gasoline fractions containing the active components of platinum, halogen, a promoter on a carrier of active alumina by dissolving an aluminum-containing reagent in an aqueous solution of a mineral acid or its aluminum salt to form an aluminum hydroxide salt, neutralizing the resulting sol with an alkaline aqueous solution agent, drip molding of sol in the forming fluid and maturation of spherical granules of aluminum hydroxide, washing, drying, calcining, feeding the obtained support with active components, drying and calcining the catalyst, characterized in that nitric acid is used as a mineral acid, aqueous ammonia is used as an alkaline agent, and aluminum hydroxide sol is neutralized until a pH of at least 11.0 is reached, the resulting suspension is treated with a solution nitric acid or aluminum nitrate to achieve a molar ratio of NO $\genfrac{}{}{0ex}{}{\text{-}}{\text{3}}$ : Al, equal to 0.7 1.3, followed by evaporation of the sol to an aluminum concentration of 110 140 g / l.  2. The method of claim 1, characterized in that metal aluminum or a mixture of aluminum with aluminum hydroxide is used as an aluminum-containing reagent.  3. The method according to PP. 1 and 2, characterized in that as the forming fluid used 6 30% aqueous solution of ammonia.

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