RU2058189C1 - Method to prepare platinum-bearing catalyst for petrol fractions reforming - Google Patents

Abstract

FIELD: oil processing. SUBSTANCE: catalyst is produced by mixing of cold and hot settling of aluminum hydroxide modifications with mass ratio (1.5 - 4) : 1. Mixture is washed, plasticized with nitric acid. Produced mass is extruded. Extrudates are dried. Temperature is raised up to 550 C and extrudates are calcined. Produced carrier is impregnated with solution of active components, among which there are platinum compounds. Impregnated granules are dried, calcined in stream of dry air with share of steam for no more than 60 minutes under temperature of 110 - 500 C. EFFECT: method allows to improve platinum-bearing catalysts production. 1 tbl

Description

 The invention relates to oil refining, and more particularly to methods for the production of platinum-containing catalysts for processing gasoline fractions by reforming.

Gamma alumina is widely used as a carrier for reforming catalysts, which is most often obtained by precipitation of hydroxide from aqueous solutions of sodium aluminate and mineral acids, mainly nitric acid, followed by molding and heat treatment [1] - [8] Usually, the deposition operation is carried out in one step at more or less constant temperature ranging 20-80 ^{° C} and pH of the slurry, close to neutral [1] [3] a weakly alkaline [4] [6] or weakly acidic [7], [8] and the prepared pseudoboehmite (boehmite ) hydroxide.

 A carrier made of the latter in the form of gamma-alumina has acceptable mechanical and physicochemical properties, however, platinum-containing reforming catalysts based on it are not stable enough. Their selectivity, especially with respect to aromatization (dehydrocyclization) of paraffin hydrocarbons, also needs to be increased.

A method of producing pseudoboehmite double-beam deposition method [9] This method provides separate precipitation of so-called "cold" (X) and "hot" (T) hydroxide modifications obtained at a temperature of about 20 ^{° C} and pH 9.0-9.5 pulp and at a temperature of 100-102 ^{° C} and pH 8,5-8,9 pulp respectively. A mixture of these two modifications in the ratio X: G = 1: 1 gives ultimately gamma-oxide granules suitable as a support for reforming catalysts (support A-64).

 However, the carrier obtained is cracked upon application of active components to it, and rifoming catalysts based on this carrier have a low selectivity and stability.

Closest to the proposed method in technical essence is a method of preparing a catalyst for reforming gasoline fractions, according to which, separate precipitation of aluminum hydroxide from solutions of sodium aluminate and nitric acid is carried out in two stages: at room temperature and at boiling; mixed modifications of aluminum hydroxide of cold and hot deposition in a mass ratio of 1: (1.5-4.0); washed aluminum hydroxide from impurities; carry out plasticization, molded; carrier is subjected to a heat treatment at 110-550 ^{° C} in flowing air; impregnate alumina with an aqueous solution of active components; dried and calcined the resulting catalyst at 110-500 ^about [10]
An increase in the proportion of modification of aluminum hydroxide of hot deposition (boehmite) when mixed with a modification of aluminum hydroxide of cold precipitation (pseudoboehmite) leads to the development of large pores and the disappearance of cracking of the granules of the carrier upon impregnation. The stability of the catalysts prepared by this method exceeds the stability of the catalysts on the support A-64. However, the catalysts obtained by the described method have a low selectivity.

 The purpose of the invention is the creation of a method for the preparation of a platinum-containing catalyst for reforming gasoline fractions, which would increase the selectivity of the catalyst while maintaining high activity and stability by mixing the modifications of aluminum hydroxide cold and hot deposition in a certain ratio.

A method for preparing a platinum-containing catalyst for reforming gasoline fractions by mixing modifications of aluminum hydroxide cold and hot precipitation with a mass ratio of (1.5-4): 1, washing, plasticizing, molding, drying, calcining, impregnating alumina with an aqueous solution of active components, including the compound of platinum, drying and calcining the resulting catalyst at 110-500 ^about C.

 An essential distinguishing feature of the proposed method is the mixing of aluminum hydroxide modifications of cold and hot deposition at a mass ratio of (1.5-4): 1.

 Analysis of the known technical solutions in the field of the production of a platinum-containing catalyst for reforming gasoline fractions allows us to conclude that there is no sign in them that is similar to the essential distinguishing feature of the claimed technical solution to the requirement of an inventive step.

 The effect of increasing selectivity, discovered by chance, can be explained by a change in the porous structure and, possibly, chemistry of the surface of the support, which should change the distribution of platinum over different pores and its state (electron deficiency and dispersion).

In addition, an increase in the fraction of modification of aluminum hydroxide by cold deposition leads to an increase in bulk density, specific surface area, mechanical strength and lower pore volume compared to catalysts based on A-64 support and catalysts prepared by the method taken as a prototype. The increase in the bulk density of the carrier can reduce the platinum content in the catalysts without compromising performance. The transition from a catalyst with a bulk density of 0.65 g / cm ³ (the usual value for A-64) to 0.77 g / cm ³ reduces the platinum content in the catalyst from 0.36 to 0.30 wt. since in both cases an equal amount of platinum will be charged into the same reactor. In this case, catalysts with a lower platinum content have a higher potential stability.

 The proposed method can be used for the preparation of monometallic platinum, platinum-rhenium and polymetallic reforming catalysts.

Testing of the catalysts is carried out in reforming the gasoline fraction in a pilot plant. After loading the catalyst, it is restored under the following conditions; stepwise increase in temperature for 8 h ^to 400 ^° C and held at 400 ^{C for} 2 hours; pressure 2.0 MPa; hydrogen circulation rate 1000 ml / l of catalyst. Next, they begin to test the catalyst. The raw materials used hydrotreated gasoline fraction boiling range 70-170 ^{° C,} a sulfur content of 0.0001% and 45 Research octane method (RON).

Tests carried out in the soft mode at a temperature of 475 ^C, a pressure of 2.0 MPa, feed rate of 2.0 h ^-1, and hydrogen-gas circulation ratio 1500 Nl / l cyrya. The activity of the catalyst is characterized by the octane number of reforming, selectivity by the yield of stable catalysis. The stringent test conditions is carried out at a temperature of 515 ^C, a pressure of 1.0 MPa, the hourly space velocity of 1.8 hr ^-1 and a hydrogen-circulation gas of 1000 Nl / l of feedstock. The results of the experiment in hard mode are used to determine the stability or, equivalently, the index of the activity drop of the difference in the content of aromatic hydrocarbons in the catalysis between the 20th and 100th hours of the test.

 The possibility of industrial application of the proposed method and its advantages are confirmed by the following examples. The test results of the catalysts are shown in the table.

 PRI me R 1. Cold deposition.

300 ml of distilled water are poured into a reactor with a stirrer and a coil, and then, under continuous intensive stirring for about 2 hours, solutions of sodium aluminate and nitric acid are simultaneously poured. The volume of the aluminate solution is 555.5 ml, the concentration is 180 g of Al ₂ O ₃ / L. The product temperature is maintained in the range 15-25 ° ^C. The pH of the slurry in the reactor is kept approximately constant (9.2-9.5) by adjusting the discharge rate of the nitric acid solution. The amount of nitric acid drained is 340 ml. After draining the solutions, the hydroxide is stabilized by boiling the suspension for 1 h at a constant pH of 9.1-9.3.

The result is a suspension of aluminum hydroxide containing 125 g of pseudoboehmite, which in terms of Al ₂ O ₃ is 100.0 g

 Hot precipitation.

200 ml of distilled water is poured into the reactor, which is heated to boiling, and while stirring, sodium aluminate and nitric acid solutions are poured simultaneously for 2 hours. Aluminate solution consumption 138.9 ml, concentration 180 g Al ₂ O ₃ / l. During deposition produce boiling slurry, ie. E. The temperature is maintained in the range of 100-102 ^C. The rate of discharge of nitric acid is adjusted so that the pH of the suspension has gone beyond 8,5-8,9. The acid consumption was 85 ml.

An aluminum hydroxide suspension is obtained containing 31.6 g of boehmite, which corresponds to 25.0 Al ₂ O ₃ .

Suspensions hot and cold mixed depositions, filtered water, and the precipitate was washed from the sodium nitrate water temperature of 50-90 ° ^C.

 The squeezed precipitate with a PPP of 77.5% is placed in a kneading machine, in which it is evaporated to a residual water content of 55%. 1.0 ml of nitric acid solution is added to the stripped mass for plasticization.

Then the resulting plastic mass is extruded on a screw press. The extrudates were dried for 3 hours at ¹¹⁰ ° C and then the temperature was raised to 550 ^{° C} and produce calcination for 4 hours.

 The result is a carrier extruded gamma-alumina with a ratio of cold and hot modification 4: 1 in the amount of 125 g

The carrier in the amount of 50.0 g is loaded into a rotary evaporator, the vacuum pump is turned on, and air is pumped out to a residual pressure of 50 mm Hg. then the evaporator is injected with 35 ml of distilled water. Moist extrudates are impregnated with 35 ml of an aqueous solution containing 0.27 g of platinum chloride, 0.18 g of rhenium acid, 0.30 g of HCl, 0.12 g of sulfuric acid and 0.5 g of glacial acetic acid. Together with acetic acid, 0.27 g of formic acid and 7.2 g of H ₂ O ₂ can be introduced.

The impregnation is carried out at a temperature below 20 ^{° C} for 1 hour, then at a temperature of 75-105 ^{° C} until the complete removal of excess water.

Impregnated granules are dried and calcined in a stream of dry air with water vapor content of not more than 60 min ^-1 at 110-500 ^{° C} and held at 500 ^{° C} for 3 hours.

 The composition of the obtained catalyst, wt. platinum 0.26, rhenium 0.26, chlorine 1.2, sulfur 0.1, aluminum oxide the rest.

 The catalyst is reduced and tested under the above conditions.

 Test results: activity 93.3 IOI, selectivity 86.0 wt. stability of 10 units.

 PRI me R 2. 100 g of aluminum oxide prepared according to example 1, impregnated with 150 ml of an aqueous solution containing 0.946 g of platinum chloride, 0.7 g of hydrogen chloride and 0.11 g of sulfuric acid.

 The conditions of impregnation, drying and calcination are similar to example 1. The composition of the obtained catalyst, wt. platinum 0.45, chlorine 1.1, sulfur 0.1, aluminum oxide the rest.

 The catalyst is reduced and tested under the indicated conditions.

 The test results: the activity of 93.4 IOI, the selectivity of 84.9 wt. stability of 19 units.

PRI me R 3. Receive 100 g of aluminum oxide analogously to example 1, but the modification of aluminum hydroxide cold and hot deposition is mixed at a mass ratio of 3: 1 (Al ₂ O ₃ ). The catalyst is prepared by impregnating alumina with 150 ml of an aqueous solution containing 0.76 g of platinum chloride, 0.49 g of rhenium acid, 0.9 g of hydrogen chloride, 0.11 g of sulfuric acid.

 The conditions for impregnation, drying and calcination are similar to example 1.

 The composition of the obtained catalyst, wt. platinum 0.36, rhenium 0.36, chlorine 1.25, sulfur 0.1, aluminum oxide the rest.

 The catalyst is reduced and tested under the above conditions. Test results: catalyst activity is 94.1 IOI, selectivity 84.8 wt. stability of 10 units.

PRI me R 4. Receive 125 g of aluminum oxide analogously to example 1, by the modification of aluminum hydroxide, cold and hot deposition are mixed at a mass ratio of 2: 1 (Al ₂ O ₃ ). The catalyst is prepared by wetting 50 g of the carrier with 35 ml of distilled water, and then impregnating alumina with 35 ml of an aqueous solution containing 0.27 g of platinum-hydrochloric acid, 0.28 g of rhenium acid, 0.36 g of HCl, 0.12 g of sulfuric acids.

 The conditions for impregnation, drying and calcination are similar to example 1.

 The composition of the obtained catalyst, wt. platinum 0.26, rhenium 0.40, chlorine 1.35, sulfur 0.1, aluminum oxide the rest.

 The catalyst is reduced and tested under the given conditions.

 The test results of the catalyst: activity 94 IOI, selectivity 86.0 wt. stability 9 units

PRI me R 5. Receive 100 g of aluminum oxide analogously to example 1, by the modification of aluminum hydroxide, cold and hot deposition are mixed at a mass ratio of 1.5: 1 (Al ₂ O ₃ ). The catalyst is prepared analogously to example 3.

 The composition of the obtained catalyst, wt. platinum 0.36, rhenium 0.36, chlorine 1.25, sulfur 0.1, aluminum oxide the rest. The catalyst is reduced and tested under the above conditions. Test results: activity 92.4 IOI, selectivity 84.6 wt. stability of 11 units.

 PRI me R 6. On a carrier prepared analogously to example 4, prepare two samples of the catalyst containing 0.36 wt. platinum and rhenium; and additional promoter metals.

 0.2 wt.% Is introduced into the first sample (A). zinc, for which 0.29 g of zinc nitrate (per 50 g of aluminum oxide) is added to the impregnating solution of a similar composition according to example 3. An impregnating solution of the composition analogous to Example 3 is applied to another portion of a carrier taken in an amount of 50 g, but with the addition of 0.06 g of zinc nitrate and 0.034 g of tungsten acid. The resulting catalysts are dried, calcined in accordance with the procedure described in example 1. Get the catalysts of the compositions, wt.

 Sample A: platinum 0.36, rhenium 0.36, zinc 0.2, chlorine 1.25, sulfur 0.1, aluminum oxide the rest.

 Sample B: platinum 0.36, rhenium 0.36, zinc 0.05, tungsten 0.05, chlorine 1.25, sulfur 0.1, aluminum oxide the rest.

 The catalysts are reduced and tested under the conditions indicated.

 Both catalysts give the same results when testing, namely: activity 92.8 IOI, selectivity 84.8 wt. stability of 11 units

 PRI me R 7. Two portions of 50 g of the carrier, prepared analogously to example 4, are impregnated with solutions of the active components, but 0.31 g of magnesium nitrate and 0.08 g of cobalt nitrate are additionally added to one impregnation solution and a sample A is obtained. To obtain a catalyst (sample B), 0.20 g of magnesium chloride and 0.05 g of nickel carbonate are added to the impregnation solution.

 The resulting catalysts are dried, calcined in accordance with the procedure described in example 1. They have the following composition, wt.

 Sample A: platinum 0.26, rhenium 0.40, magnesium 0.1, cobalt 0.05, chlorine 1.25, sulfur 0.1, aluminum oxide the rest.

 Sample B: platinum 0.26, rhenium 0.40, magnesium 0.05, nickel 0.05, chlorine 1.25, sulfur 0.1, aluminum oxide the rest.

 The catalysts are reduced and tested under the above conditions.

 When tested, both catalysts show the same results: activity 94.0 IOI, selectivity 85.7% stability 10 units

 PRI me R 8. Two portions of 50 g of the carrier, prepared analogously to example 4, are impregnated with solutions of active components. In general, the impregnation conditions are similar to those in Example 1, however, the amount of rhenic acid is increased in both cases by a factor of 2.3 and, in addition, additional components are added to the solutions.

 In the case of catalyst for sample A: 0.038 g of barium chloride and 0.034 g of tungsten acid, and in the case of catalyst for sample B, 0.038 g of barium chloride and 0.11 g of tin tetrachloride.

 The resulting catalysts are dried, calcined in accordance with the procedure described in example 1. They have the following compositions, wt.

 Sample A: platinum 0.26, rhenium 0.60, barium 0.05, tungsten 0.05, chlorine 1.25, sulfur 0.1, aluminum oxide the rest.

 Sample B: platinum 0.26, rhenium 0.60, barium 0.05, tin 0.1, chlorine 1.25, sulfur 0.1, aluminum oxide the rest.

 The catalysts are reduced and tested under the above conditions.

When testing the catalysts, the following results were obtained:
Sample A: activity 94.3 IOI, selectivity 96.0 wt. stability of 10 units.

 Sample B: activity 94.1 IOI, selectivity 85.7 wt. stability of 11 units

PRI me R 9 (known method). Get 300 g of aluminum oxide analogously to example 1, by the modification of aluminum hydroxide, cold and hot deposition are mixed at a mass ratio of 1: 1 (Al ₂ O ₃ ).

 100 g of support are used to prepare a monometallic platinum catalyst. To do this, alumina is impregnated with an aqueous solution of the active components as in example 2.

 Another 100 g of the carrier are impregnated with an aqueous solution of the active components, as in Example 3.

 An impregnating solution is applied to the remaining portion of the carrier as in Example 3 of the composition, but with the addition of zinc and tungsten, as in Example 6.

 The resulting catalysts are dried, calcined in accordance with the procedure described in example 1.

 The compositions of the obtained catalysts, wt.

monometallic: platinum 0.45, chlorine 1.2, sulfur 0.1, aluminum oxide else;
platinum-rhenium: platinum 0.36, rhenium 0.36, chlorine 1.25, sulfur 0.1, aluminum oxide else;
polymetallic: platinum 0.36, rhenium 0.36, zinc 0.05, tungsten 0.05, chlorine 1.25, sulfur 0.1, aluminum oxide the rest.

 The catalysts are reduced and tested under the above conditions.

 When testing the catalysts, the following results were obtained: monometallic platinum: activity 89.9 IOI, selectivity 80.6 wt. stability of 22 units; platinum-rhenium: activity 91.0 IOI, selectivity 81.0 wt. stability of 16 units. polymetallic: activity 91.8 IOI, selectivity 83.2 wt. stability of 13 units.

PRI me R 10 (prototype). Get 300 g of aluminum oxide analogously to example 1, by the modification of aluminum hydroxide, cold and hot deposition are mixed in a mass ratio of 1: 2 (Al ₂ O ₃ ).

 100 g of the carrier are taken to prepare a monometallic platinum catalyst. For this, alumina is impregnated with a solution of active components as in example 2.

 Another 100 g of alumina is impregnated with a solution of active components in the same manner as in Example 3.

 An impregnating solution of the composition analogous to Example 3 is applied to the remaining portion of the carrier, but with zinc and tungsten additives, as in Example 6. The resulting catalysts are dried and calcined in accordance with the procedure described in Example 1.

 The compositions of the catalysts, wt.

monometallic platinum 0.45, chlorine 1.0, sulfur 0.1, aluminum oxide the rest:
platinum-rhenium platinum 0.36, rhenium 0.36, chlorine 1.2, sulfur 0.1, aluminum oxide else;
polymetallic platinum 0.36, rhenium 0.36, zinc 0.05, tungsten 0.05, the rest is aluminum oxide.

 The catalysts are reduced and tested under the above conditions.

When testing the catalysts, the following results were obtained:
monometallic platinum: activity 93.3 IOI, selectivity 80.9 wt. stability of 19 units;
platinum-rhenium: activity 92.4 IOI, selectivity 82.7 wt. stability of 13 units;
polymetallic: activity 92.0 IOI, selectivity 82.9 wt. stability of 12 units.

 As follows from the data presented in the table, the catalysts prepared by the proposed method have the highest selectivity while maintaining high values of activity and stability.

Claims (1)

METHOD FOR PREPARING A PLATINUM-CONTAINING CATALYST FOR REFORMING GASOLINE FRACTIONS by mixing modifications of aluminum hydroxide cold and hot deposition, washing, plasticizing, molding, drying, calcining, impregnating aluminum oxide with an aqueous solution of active components, including a catalyst of 110 and containing a catalyst with ^o C, characterized in that the mixing of modifications of aluminum hydroxide cold and hot deposition is carried out in a mass ratio of (1.5 4) 1.

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