The method of preparation of the catalyst

 

(57) Abstract:

The invention relates to the production of catalysts, particularly copper-zinc-aluminum catalysts for low-temperature methanol synthesis and low-temperature conversion of carbon monoxide. The basis of the invention is to create a process for preparation of the catalyst having a high activity, stability and mechanical strength. This task is solved in that a method of preparation of the catalyst by deposition of nitrate salts of copper, zinc and aluminum sodium carbonate at 50-80oC, pH = 6,0-8,0 and deposition time from 3 to 60 minutes Deposition of copper-zinc or copper-zinc-aluminum compounds is performed on pre-deposited zinc-aluminum stabilizer. In addition, the deposition was carried out under continuous supply of solution in the reactor system consisting of one or more reactors, and continuous removal of the suspension from the system, and the average ASU stay the copper-zinc-aluminum compound in the reaction zone is not more than 60 minutes Offer continuous method of preparation of the catalyst allows to obtain highly active and stable catalyst. 1 C. p. F.-ly yevich catalysts for low-temperature methanol synthesis and low-temperature conversion of carbon monoxide.

There is a method of preparation of the catalyst for methanol synthesis by sequential deposition of aluminium-containing stabilizing excipient and active copper-zinc-containing composition in the presence of this filler from the corresponding nitrate solutions by adding sodium carbonate and precipitation of aluminium-containing filler lead from nitric acid solutions of zinc and aluminum and the precipitation of copper-zinc-containing composition of the nitric acid solution of copper and zinc, including aluminum nitrate, [1]

The closest technical solution is the method of preparation of the catalyst by deposition of nitrate salts of copper, zinc and aluminum sodium carbonate at 50-100oC and pH 6,0-9,0. The resulting suspension is stirred in the second tank to the establishment pH 7.0, filtered off, washed, dried, calcined and tabletirujut [2]

A disadvantage of known methods is that in the first case, get the catalyst is unstable in relation to structural changes in hydrobromide. When interacting with water, which is formed during the reaction conditions for the formation of phase hydrocalumite zinc, education which leads to the destruction of the basic structure , usnot which is recrystallization phases, increasing the degree of order of the crystals hydroxocobalamin, reducing the mutual solubility of the phases. The result is a decrease in the activity of the catalyst. In addition, the crystal growth leads to the fact that when the pelletizing unit cross-section of the tablet is formed smaller number of contacts between particles, and therefore reduces the strength of the tablets.

The objective of the invention is to provide a process for preparation of the catalyst having a high activity, stability and mechanical strength by obtaining optimal patterns of sediment catalyst precursor.

The problem is solved in such a way that in the preparation method of the catalyst by precipitation from solutions of nitrates of copper, zinc and aluminum sodium carbonate solution at 50-80oC, pH is from 6.0 to 8.0, followed by separation of the precipitate, washing drying, calcination and pelletizing according to the invention the deposition was carried out under continuous supply of solutions in the reaction system consisting of one or more reactors, and continuous removal of the suspension from the system, and the average time of stay of the copper-zinc-aluminum compounds of the unity of conduct on pre-precipitated at pH 5.0-6.0 zinc-aluminum stabilizer.

The proposed method for the preparation of the catalyst is as follows. The solution of nitrate of copper, zinc and aluminum or copper and zinc is directed into the deposition reactor. This also serves the solution of the carbonate of an alkali metal. The deposition is carried out in a batch reactor or in a reactor with continuous removal of the suspension, or in a cascade of consecutive reactors. The feed rate of the solutions and their ratio is chosen in such a way as to maintain a pH of 6-8, and the residence time of sediment reaction zone was 3-60 minutes the Temperature in the reaction zone support 50-80oC. To improve the stability of the catalyst in the reactor impose a suspension of previously deposited zinc-aluminum stabilizer. Last precipitated by draining the solution of nitrates of zinc and aluminum with a solution of carbonate of an alkali metal at a pH of 5-6. The precipitate catalyst precursor is separated from the mother liquor, washed, dried, calcined and tabletirujut. You can use the catalyst in a 'green' form or in the form of a mixture of calcined and 'green' catalyst.

The process of accelerated deposition, in which the average residence time of the deposited mass in Rea the military structure. Get fine disordered hydroxocobalamine compounds of copper, zinc and aluminum after decomposition at the stage of calcination give a high degree of dispersion of oxides, providing a large surface values and the activity of the catalyst.

The use of reactors with continuous removal of the reaction products allows to stabilize the parameters of the deposition process. Use in the reactor system, several reactors can improve the productivity of the production line, and also approximates the distribution of the deposited substance on the residence time in the reactor system to a more optimal linear. The formation of particles of different degrees of dispersion, which will provide catalytic activity for the duration of the period of their operation.

Introduction into the reactor pre-precipitated at pH 5-6 zinc-aluminum compounds improves the stability of the catalysts, since the particles of the zinc-aluminum spinel is more thermally stable in comparison with oxides of copper and zinc and limit their recrystallization during operation. The presence of zinc oxide in the stabilizer neutralizes the acidic centers of aluminum oxide and thereby the connection when the calcination which forms a zinc-aluminum spinel. In addition, stabilizer, precipitated at pH 5-6 more resistant to structural changes in hydrobromide in contrast to the known, deposited at pH 6-8. Use a pH above 7 leads to the formation along with spinel other zinc-aluminum phases, which reduces the activity and stability of catalyst.

The application of the proposed method for preparation of catalysts for methanol synthesis and the conversion of carbon monoxide in industrial conditions allow to increase, compared with the existing technology, activity and stabiles obtained catalysts, as well as to increase the mechanical strength of the tablets at a given density. On the other hand, the application of the proposed method in a continuous mode of deposition will increase the level of automation of production and the introduction of more modern technology, in particular, at the stage of sedimentation and filtration.

Example 1 (comparative). 1.5 l of a solution of nitrate of copper, zinc and aluminum is poured together with the sodium carbonate solution for 30 min, maintaining the pH of the mixture to 6.5-7.0 and a temperature of 85oC. the Suspension is stirred at 85oC 60 min before the establishment of postwait at 300oC 6 h resulting product tabletirujut after adding 2% of graphite and receive tablets 5x5 mm with crushing strength of 5.6 MPa.

The catalyst was tested in the synthesis of methanol in the form of fractions of 0.25-0.5 mm under a pressure of 5 MPa, a temperature of 220oC, synthesis gas composition H2:CO OF 2:1, 5% CO2, the volumetric rate of 10,000 1/h

The temperature estimate of the change in the dispersion of crystallites of copper when heated in a heat chamber that is installed on the x-ray diffractometer, through which the purge gas is a reducing agent. These tests are given in the table.

Examples 2-16. For preparation of a solution of nitrate of copper, zinc and aluminum 1270 g of copper powder, 814 g of zinc oxide and 1200 nitrate devyativodny mixed with 5 l of demineralized water. Gradually add 6,2 l 56% nitric acid. After complete dissolution of the components of the solution volume was adjusted with water to 33.5 HP

To prepare the solution of the nitrates of copper and zinc 1270 g of copper powder and 814 g of zinc oxide is mixed with 5 l of demineralized water. Gradually add 6,2 l 56% nitric acid. After complete dissolution of the components of the solution volume was adjusted with water to 32.1 l

To prepare the solution of nitrates is. Ostapenko add 1.7 l 56% nitric acid. After complete dissolution of the components of the solution volume was adjusted ode to 20 liters

For preparation of a solution of sodium carbonate 1300 g of sodium carbonate dissolved in anhydrous 8,7 liters of demineralized water.

1.5 l of a solution of nitrate of copper, zinc and aluminum is poured together with approximately the same number of carbonate solution three, maintaining a constant pH and temperature. The time of deposition 3-60 minutes, the Suspension is filtered, the precipitate washed with water, dried at 110oC 12 h and calcined at 300oC 6 h

You can pre-precipitated zinc-aluminum stabilizer. For this purpose, 100 ml of a solution of nitrates of zinc and aluminum is poured together with sodium carbonate solution, maintaining a constant pH and temperature. Then in the same reactor formed stabilizer is drained 1.5 liters of a solution of nitrate of copper, zinc and aluminium (or 1.5 l of a solution of nitrate of copper and zinc) together with approximately the same amount of sodium carbonate solution, maintaining a constant pH and temperature. The time of deposition 3-60 minutes, the Suspension is filtered, the precipitate washed with water, dried at 110oC 12 h and calcined at 300oC 6 h resulting product tabletirujut after adding 2 the results of the testing of the catalysts shown in the table.

In examples 13-16, the deposition is carried out in the reactor of continuous action, the suspension of which is continuously withdrawn through the overflow fitting on the filter, or in a cascade of two reactors, the first of which precipitated zinc-aluminum stabilizer and the second active phase of the catalyst. The volume of the reactor to the overflow fitting 1 l

4 l of a solution of nitrate of copper, zinc and aluminum is poured simultaneously with approximately the same quantity of sodium carbonate solution, maintaining a constant pH and temperature. The rate of draining of the solution of nitrates support to provide the necessary average residence time of suspension in the reaction zone. The suspension is continuously withdrawn by filtration. The precipitate is washed with water, dried at 110oC 12 h and calcined at 300oC 6 h resulting product tabletirujut after adding 2% of graphite and receive tablets 5x5 mm Conditions of preparation and testing of catalysts shown in the table.

Example 17. 350 g of copper powder, 450 g of zinc oxide and 900 g of aluminium nitrate deviations mixed with 5 l of demineralized water. Gradually add the 2.2 l 56% nitric acid. After complete dissolution of the components of the solution volume was adjusted with water is the right time in the reactor of continuous action, maintaining a pH of 6.5 and a temperature of 70oC. the Rate of draining of the solution of nitrate of 1.5 l/h (mean residence time of suspension in the reaction zone 20 min). The suspension is filtered, the precipitate washed with water, dried at 110oC 12 h and calcined at 300oC 6 h resulting product tabletirujut after adding 2% of graphite and receive tablets 5x5 with crushing strength of 12 MPa.

For testing the activity of preparing a fraction 2-3 mm. Test activity in the reaction of carbon monoxide conversion is conducted under the following conditions: space velocity of 5000 to 1. h steam:gas ratio of 0.7:1, the composition of the gas,about. CO 12,5, CO29,4, H255,0, 33,1. Activity is the rate constant for the reaction according to equation 1 order by carbon monoxide in the kinetic mode, cm3/g at 225oC is equal to 15.

From the table it is seen that the catalysts prepared in examples 2-16, superior to the prototype (example 1) strength tablets, productivity, and are more heat resistant. The examples illustrate the effect of pH, temperature and deposition time. The decrease of deposition time leads to increased dispersion of the catalyst and, consequently, to increased activity. The increase in pH and temperature deposition is equivalent to increasing visitor pre-deposited stabilizer increases thermostability, which is the higher the lower the pH of the deposition of the stabilizer (examples 9-11). In example 12 shows that the introduction of aluminum into the main part of the catalyst is not required. Examples 13-16 show a positive effect when using the method of continuous deposition. The average residence time of particles in the reactor equivalent of deposition time at periodic deposition. The output of the average time for the claimed range (example 15) leads to a deterioration of characteristics of the catalyst. Deposition with a stabilizer (example 16) and here gives a positive effect for heat stability.

1. The method of preparation of the catalyst by deposition from solutions of nitrates of copper, zinc and aluminum with a solution of sodium carbonate at 50 80oWith a pH of 6.0 to 8.0, followed by separation of the precipitate, washing, drying, calcination and pelletizing, characterized in that the deposition was carried out under continuous supply of solutions in the reaction system consisting of one or more reactors, and continuous removal of the suspension from the system, and the average time of stay of the copper-zinc-aluminum compound in the reaction zone is 3 to 60 minutes

2. The method according to p. 1, characterized in that the deposition of copper-circoviridae.

 

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FIELD: industrial organic synthesis catalysts.

SUBSTANCE: invention relates to copper-containing catalysts for low-temperature synthesis of methanol in fluidized bed at median pressure and provides catalyst, whose preparation involves impregnation and which contains oxides of copper, zinc, chromium, magnesium, aluminum, boron, and barium and has following molar ratio: CuO:ZnO:Cr2O3, MgO:Al2O3:B2O3:BaO = 1:0.3:(0.014-0.038):(0.047-0.119):(0.05-0.1):(0.007-0.014):(0.0292-0.054).

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SUBSTANCE: invention relates to copper-containing catalysts for low-temperature synthesis of methanol in fluidized bed at low pressure and provides a wear-resistant catalyst, whose preparation involves impregnation and which contains oxides of copper, zinc, chromium, magnesium, aluminum, and boron and has following molar ratio: CuO:ZnO:Cr2O3, MgO:Al2O3:B2O3 = 1:0.3:(0.15-0.2):(0.1-0.025):(0.25-0.3):(0.08-0.1).

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FIELD: disproportionation process catalysts.

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