The method of processing chromium catalysts

 

(57) Abstract:

The invention relates to the field of cooking chromium catalysts used for a wide range of catalytic processes, for example, conversion, digidrive, origene, polymerization and other. The invention solves the problem of disposal of chromium catalysts from ions of Cr+6by treating the catalyst solutions of carboxylic acid-reducing agent with a concentration of 20 to 100 g/l for 15 to 120 minutes at a temperature of 20 - 100oC. the Activity of the catalyst treated according to the invention, is not reduced. 8 C.p. f-crystals.

The invention relates to the field of cooking chromium catalysts are widely used for a number of large chemical processes, such as the conversion of carbon monoxide with water vapor, the conversion of gaseous hydrocarbons, methanol synthesis, hydrogenation of alcohols, ketones, esters, nitro compounds, obtaining monomers, gas cleaning, etc. /1-3/

Depending on the composition of the chromium catalysts and preparation conditions in the finished catalyst along with dominant content of chromium in the oxidation state +3 is a significant amount of high-valent chromium ions (Cr+the established limits.

At the same time with the help of chemical analysis shows that for a number of known oxide alumomagnesium catalysts, the content of Cr+6can reach up to 2 wt. and more.

From the literature authors unknown ways of disposal of chromium catalysts.

The invention solves the problem of creating a method of processing catalysts, which would neutralize them from ions of Cr+6to prevent the catalyst from the regeneration of ion Cr+6when stored at ambient temperatures without reducing the catalytic activity of the catalysts.

This problem is solved by treating the catalyst compounds-reducing agents with the formation on the catalyst surface carbonate and carboxylate groups. As such reducing and carboximidic agents are encouraged to use carboxylic acids.

The method of processing chromium catalysts is as follows.

Chromium catalysts are incubated in a solution of carboxylic acid-reducing agent with a concentration of 20 to 100 g/l at a temperature of 20 - 100oC for 15 to 120 min, followed by drying at a temperature of 20 - 120oC. as carboxylic acids using the sorrel is one of their processing inorganic reducing agent.

As a typical chromium catalyst used catalyst afterburning ICT-12-8 containing oxide compound of copper and chromium (copper in terms of CuO 10 wt. chromium in terms of Cr2O320 wt. the rest of gamma-Al2O3). The content of Cr+6in the original catalyst of 0.9 wt. The activity of the catalysts before and after treatment to determine flow-circulation method in the model reaction of deep oxidation of methane at 500oC, the initial concentration of methane of 0.5% vol. and the degree of conversion of 50% of the activity of the raw catalyst is 0,510-2cm3/g S. in Addition, the treated catalyst of low-temperature CO conversion NTC-4 the following composition: Cr (in terms of Cr2O3) 14 wt. Cu in terms of CuO) 54 wt. Zn (in terms of ZnO) 11 wt. Al2O3- the rest. The activity of the untreated catalyst in the model reaction of methane oxidation 0,3510-2cm3/g C.

Example 1. 10 g of the catalyst of ICT-12-8 is treated with a solution of oxalic acid with a concentration of 20 g/l at a temperature of 20oC for 30 minutes and Then dried in air at a temperature of 120oC for 4 h, the Content of Cr+60.71 wt. activity in the oxidation of round 40oC. the Content of Cr+60.6. activity in the oxidation of methane 0,510-2cm3/g C.

Example 3. 10 g of catalyst is treated with oxalic acid with a concentration of 90 g/l at a temperature of 20oC for 2 h and Then dried in air at a temperature of 120oC 4 o'clock the Content of Cr+60.4. activity in the oxidation of methane 0,410-2cm3/g C.

Example 4. Similar to example 3, but the treatment is carried out at a temperature of 40oC for 30 minutes, the Contents of Cr+6less than 0.01 wt. activity in the oxidation of methane 0,5210-2cm3/g C.

Example 5. Similar to example 3, but the treatment is carried out at a temperature of 60oC for 30 minutes, the Contents of Cr+6less than 0.01 wt. activity in the oxidation of methane 0,510-2cm3/g C.

Example 6. Similar to example 3, but the treatment is carried out at a temperature of 100oC for 15 minutes, the Contents of Cr+6less than 0.01 wt. activity in the oxidation of methane 0,5510-2cm3/g C.

Example 7. 10 g of catalyst is treated with a solution of oxalic acid with a concentration of 90 g/l at a temperature of 40oC for 30 min and dried in air at room temperature for 12 hours, the Content of Cr+6+6less than 0.01 wt. activity in the oxidation of methane - 0,510-2cm3/g C.

Example 9. 10 g of the catalyst of ICT-12-8 is treated with a solution of formic acid with a concentration of 100 g/l at a temperature of 40oC for 30 min and dried in air at a temperature of 120oC 4 o'clock the Content of Cr+6less than 0.01 wt. activity in the oxidation of methane - 0,610-2cm3/g C.

Example 10. Similar to example 9, but the treatment is carried out at 100oC for 15 minutes, the Contents of Cr+6less than 0.01 wt. activity in the oxidation of methane 0,710-2cm3/g C.

Example 11. 10 g of the catalyst of ICT-12-8 is treated with a solution of oxalic acid with a concentration of 50 g/l at 40oC for 60 minutes, the Content of Cr+6less than 0.01 wt. activity in the oxidation of methane - 0,5310-2cm3/g C.

Example 12. 10 g of the catalyst of ICT-12-8 restore in a stream of air at 300oC for one hour, then treated for 30 min with a solution of oxalic acid (90 g/l) and dried at 1200oC 4 o'clock the Content of Cr+6less than 0.01 wt. activity in the oxidation of methane - 0,510-2cm3oC 1 o'clock the Content of Cr+6less than 0.01 wt. activity in the oxidation of methane 0,610-2cm3/g C.

Example 14. (For comparison). 10 g of the catalyst of ICT-12-8 boiled for 1 h in distilled water and dried at 120oC 4 o'clock the Content of Cr+60.9 wt. activity in the oxidation of methane - 0,510-2cm3/g C.

Example 15. 10 g of the catalyst NTC-4 treated at 60oC for 60 min oxalic acid with a concentration of 80 g/l and dried for 3 h at 100oC. the Content of Cr+6less than 0.01 wt. activity in the oxidation of methane 0,410-2cm3/g/s

Thus, as can be seen from the description and examples, the processing of chromium catalysts according to the invention allows to almost completely neutralize the catalyst from Cr+6without compromising catalytic properties.

The proposed method can be widely used in chemical, petrochemical and other industries.

1. The method of processing chromium catalysts, characterized in that the catalyst is kept in a solution of carboxylic acid-reducing agents, followed by drying.

2. The method according to p. 1, characterized in that as karbonovoi acid using formic acid.

4. The method according to p. 1, characterized in that a mixture of oxalic and formic acids.

5. The method according to p. 1, characterized in that the concentration of carboxylic acids 20 to 100 g/l

6. The method according to p. 1, characterized in that the catalyst is kept in a solution of acid at 20 to 100oC.

7. The method according to p. 1, characterized in that the catalyst is kept in the solution for 15 to 120 minutes

8. The method according to p. 1, characterized in that the drying is carried out at 20 - 120oC.

9. The method according to p. 1, wherein before curing catalysts in a solution of carboxylic acid it is treated with an inorganic reducing agent.

 

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