CN101961654A - Method for regenerating carbonyl sulfide hydrolysis catalyst after inactivation - Google Patents

Abstract

The invention provides a method for regenerating a deactivated carbonyl sulfide hydrolysis catalyst. The deactivated catalyst is washed with water for 20-40 minutes under ultrasonic-assisted conditions, and then dried at 60-80°C for 10-12 hours; Under auxiliary conditions, after impregnating with impregnation solution for 20-40 minutes, dry at a temperature of 60-80°C for 10-12 hours; place it in a muffle furnace at a temperature of 250-450°C and a heating rate of 5°C/min , Calcined for 1 to 3 hours to obtain a regenerated catalyst. The regeneration method adopted in the present invention has simple process, especially low roasting temperature, saves energy, and is easy to industrialized production, and the compound of alkali metal in the impregnating agent is cheap and easy to obtain, the cost is low, the catalytic activity after regeneration is high, and can The regenerated catalyst of the invention can make the conversion rate of COS reach more than 90% after multiple regenerations.

Description

A kind of regeneration method after deactivation of carbonyl sulfide hydrolysis catalyst

technical field

The invention relates to a regeneration method of a deactivated catalyst, in particular to a regeneration method of a deactivated low-temperature carbonyl sulfide hydrolysis catalyst.

Background technique

COS is the main form of organic sulfur in industrial gases. Trace amounts of COS in industrial production can easily cause catalyst poisoning and deactivation, and have a corrosive effect on industrial production equipment. In addition, COS emitted into the atmosphere without treatment can form SO ₂ , promote photochemical reactions, and eventually transform into sulfate aerosols, causing serious environmental problems. Recently, the research on the removal of COS is mostly hydrolysis. Under the action of hydrolysis catalyst, the water vapor in the tail gas or raw material gas is used to convert COS into easier-to-handle inorganic sulfur hydrogen sulfide (H ₂ S), and then sulfide Hydrogen is removed by other means.

CN1069673A discloses a COS hydrolysis catalyst with γ-Al ₂ O ₃ as the carrier and K ₂ CO ₃ as the active component. The catalyst has a good hydrolysis effect on COS and other sulfides, and also has a good absorption effect on H ₂ S. However, after these hydrolysis catalysts have been operated for a period of time, their activity has decreased significantly, but the content of active components in the deactivated catalysts is still high, and the mechanical strength has changed little. Therefore, it is necessary to regenerate them to prolong their service life and save money. Improve efficiency.

Hydrotalcite (Layered Double Hydroxides, LDHs) is a kind of natural clay-like material with layered microporous structure, which has a large specific surface area and exchangeable anions between layers. Hydroxy metal composite oxide. LDHs are relatively stable below 400°C. At high temperatures, interlayer water and anions are removed to form composite oxides or special hydroxides of various metals. These composite oxides have high specific surface area and strong alkalinity. After high-temperature roasting, it can be used as a catalyst or carrier, mainly used as a variety of basic catalysts and redox catalysts and carriers. With the help of the basicity and redox properties of this type of composite oxide, it has also been used to develop environmental catalysts.

Dennis E.Sparks etc. disclosed in Applied Catalysis B: Environmental, 2008, (82): 58-66 that a series of hydrotalcites were prepared by co-precipitation method, and the adsorption performance of the calcined oxide on COS was studied. The results show that the derived oxides of hydrotalcites have a good adsorption effect on COS.

According to literature reports, the hydrolysis reaction of COS is a base-catalyzed reaction, and the composite oxides after high-temperature calcination of hydrotalcite-like compounds have high specific surface area, dispersion and strong alkalinity, but the application of hydrotalcite-like composite oxides in COS There is no practical and effective report on the regeneration method after hydrolytic inactivation.

Contents of the invention

In order to overcome the problems of incomplete use of the catalyst and inconspicuous adsorption of COS, the object of the present invention is to provide a regeneration method after deactivation of the carbonyl sulfide hydrolysis catalyst, so that the deactivation of the carbonyl sulfide hydrolysis catalyst can be regenerated and prolong its service life , save resources, and realize through the following technical solutions.

A regeneration method after deactivation of carbonyl sulfide hydrolysis catalyst is characterized in that through the following steps:

A. Wash the deactivated catalyst with water for 20-40 minutes under ultrasonic-assisted conditions, and then dry it at 60-80°C for 10-12 hours;

B. Immerse the dried catalyst in step A with an impregnation solution for 20 to 40 minutes under ultrasonic-assisted conditions, and then dry it at a temperature of 60 to 80° C. for 10 to 12 hours;

C. Calcining for 1-3 hours at a temperature of 250-450° C. and a heating rate of 5° C./min to obtain a regenerated catalyst.

The catalyst is the catalyst involved in the Chinese patent application (application number: 200910218242.7), which is a carbonyl sulfide hydrolysis catalyst prepared with Co-Ni-Al hydrotalcite as a precursor.

Ultrasonic auxiliary conditions for the steps A and B are: using a conventional ultrasonic instrument, and controlling the temperature to 30° C. and the frequency to 28 or 40 KHz.

The water in the step A is distilled water.

The impregnating agent in the step B is NaOH and/or Na ₂ CO ₃ solution.

The impregnating agent in the step B is preferably a NaOH solution with a concentration of 3.5 mol/L or/and a Na ₂ CO ₃ solution with a concentration of 1 mol/L.

The activity test of the catalyst of the present invention is carried out in a fixed-bed reactor, and the conditions are that the diameter of the reactor is 4mm, the height of the catalyst is 4cm, the reaction temperature is 60°C, the space velocity is 3000h ^-1 , the COS concentration is 1100mg/ ^m3 , and the oxygen content is 1%. The relative humidity is 2.4%, and the activity is expressed by COS hydrolysis removal rate.

Effects and advantages achieved by the present invention: the regeneration method adopted by the present invention has simple process, especially low roasting temperature, energy saving, and easy industrial production, and the alkali metal compound in the impregnating agent is cheap and easy to obtain, the cost is low, and regeneration The final catalyst has high catalytic activity and can be regenerated multiple times. The regenerated catalyst of the invention can make the conversion rate of COS reach more than 90%.

Description of drawings

Fig. 1 is the carbonyl sulfide conversion efficiency change figure with time of embodiment 1;

Fig. 2 is the graph of carbonyl sulfide conversion efficiency over time of embodiment 2;

Fig. 3 is the graph of carbonyl sulfide conversion efficiency over time of embodiment 3;

Fig. 4 is the graph of carbonyl sulfide conversion efficiency over time of embodiment 4;

Fig. 5 is the graph of carbonyl sulfide conversion efficiency over time of embodiment 5;

Figure 6 shows the effect of catalyst regeneration times on catalyst activity.

Detailed ways

The present invention will be further described below in conjunction with the examples.

The deactivated catalyst used in the following examples is a carbonyl sulfide hydrolysis catalyst prepared from Co-Ni-Al hydrotalcite as a precursor, and the preparation process is as follows:

(1) Weigh 2.9103g Co(NO ₃ ) ₂ ·6H ₂ O, 11.6320gNi(NO ₃ ) ₂ ·6H ₂ O and 9.3782gAl(NO ₃ ) ₃ ·9H ₂ O and dissolve them in 25ml of distilled water to make solution A ; Take NaOH and Na ₂ CO ₃ as precipitating agents, dissolve 5.2995g Na ₂ CO ₃ and 7g NaOH in 50ml distilled water, and make solution B;

(2) Transfer the prepared A solution to a separatory funnel, and drop the A solution into the B solution at a rate of 3.6 mL/min under room temperature and mechanical stirring, and control the pH of the solution at the end of the addition to be 9. After the dropwise addition, the stirring was continued for 30 minutes to obtain a suspension at last;

(3) crystallize the suspension obtained in step (2) in a water bath at 50° C. for 12 hours;

(4) suction filter the product obtained by crystallization, and wash it with distilled water to make it neutral, put the obtained product in an oven, and dry it at a temperature of 60°C;

(5) The product obtained in step (4) is placed in a resistance furnace, and roasted at 350°C for 2 hours in an air atmosphere. The roasted product is ground, pressed into tablets, and sieved, and 40-60 mesh powder is taken to obtain the class The hydrotalcite-derived composite oxide catalyst is used to obtain a deactivated catalyst.

Example 1

A. Wash 2 g of the deactivated catalyst with distilled water for 20 minutes on a conventional ultrasonic instrument at a temperature of 30°C and a frequency of 40KHz, and then dry it at 60°C for 12 hours;

B. Under the same ultrasonic-assisted conditions as above, the catalyst after drying in step A was impregnated with an impregnation solution for 40 minutes, and then dried at a temperature of 70°C for 11 hours. The impregnation solution was _dissolved in 7g of NaOH and 5.2995g of Na ₂ CO The resulting solution in 50ml of water;

C. Place the catalyst obtained in step B in a muffle furnace, and bake it at 350° C. for 2 hours, and control the temperature rise rate to 5° C./min to obtain a regenerated catalyst, whose activity is shown in FIG. 1 .

Example 2

A. Wash 2 g of the deactivated catalyst with distilled water for 30 minutes on a conventional ultrasonic instrument with the aid of ultrasonic waves at a temperature of 30°C and a frequency of 28KHz, and then dry it at 80°C for 11 hours;

B. The catalyst after drying in step A is impregnated with impregnating solution for 20 minutes under the same ultrasonic assisted conditions as above, and then dried at 60° C. for 12 hours. The impregnating solution is 7 g of NaOH dissolved in 50 ml of water. solution;

C. Place the catalyst obtained in step B in a muffle furnace, and bake it for 1.2 hours at a temperature of 400° C., and control the heating rate to 5° C./min to obtain a regenerated catalyst. The activity is shown in FIG. 2 .

Example 3

A. Wash 2 g of the deactivated catalyst with distilled water for 40 minutes on a conventional ultrasonic instrument at a temperature of 30°C and a frequency of 40KHz, and then dry it at 70°C for 10 hours;

B. Immerse the dried catalyst in step A for 30 minutes with the impregnation solution under the same ultrasonic-assisted conditions as above, and then dry it at 80°C for 10 hours. The impregnation solution is 5.2995 g of Na ₂ CO ₃ dissolved in 50 ml of water and the resulting solution;

C. Place the catalyst obtained in step B in a muffle furnace, and bake it for 2 hours at a temperature of 350° C., with a heating rate of 5° C./min, to obtain a regenerated catalyst, whose activity is shown in FIG. 3 .

Example 4

A. Wash 2 g of the above deactivated catalyst with distilled water for 35 minutes on a conventional ultrasonic instrument under ultrasonic-assisted conditions at a temperature of 30 ° C and a frequency of 28 KHz, and then dry it at 75 ° C for 10 h;

B. The catalyst after drying in step A is impregnated with impregnation solution for 25 minutes under the same ultrasonic-assisted conditions as above, and then dried at 65°C for 12 hours. The impregnation solution is 7 g of NaOH and 5.2995 g of Na ₂ CO ₃ A solution obtained by dissolving in 50ml of water;

C. Put the catalyst obtained in step B in a muffle furnace, and bake it for 3 hours at a temperature of 250° C., and control the temperature rise rate to 5° C./min to obtain a regenerated catalyst, whose activity is shown in FIG. 4 .

Example 5

A. Wash 2 g of the deactivated catalyst with distilled water for 25 minutes on a conventional ultrasonic instrument at a temperature of 30°C and a frequency of 40KHz, and then dry it at 65°C for 12 hours;

B. Immerse the dried catalyst in step A for 35 minutes with an impregnating solution under the same ultrasonic-assisted conditions as above, and then dry it at a temperature of 75°C for 10 hours. The impregnating solution is 5.2995g of Na ₂ CO ₃ dissolved in 50ml of water and the resulting solution;

C. Place the catalyst obtained in step B in a muffle furnace, and bake it for 1 hour at a temperature of 450° C., with a heating rate of 5° C./min, to obtain a regenerated catalyst, whose activity is shown in FIG. 5 .

Example 6

Use the regenerated catalyst of embodiment 3, after it deactivates again, carry out secondary regeneration by the method for embodiment 3 again, continue reaction deactivation and still carry out the third regeneration by the method for embodiment 3, still can obtain regenerated catalyst, its The effect of regeneration times on catalyst activity is shown in Figure 6.

Claims (7)

1. the renovation process behind the hydrolytic catalyst of carbonyl sulfur inactivation is characterized in that through the following step:

A. with the catalyst behind the inactivation under the ultrasonic wave subsidiary conditions, wash 20～40min with water after, at 60～80 ℃ of down dry 10～12h;

B. with the catalyst of steps A drying under the ultrasonic wave subsidiary conditions, behind maceration extract dipping 20～40min, dry 10～12h under 60～80 ℃ temperature;

C. with the catalyst of step B drying, be that 250～450 ℃, heating rate are under the 5 ℃/min condition in temperature, roasting 1～3h promptly obtains regenerated catalyst.

2. method according to claim 1 is characterized in that: described catalyst is to be the hydrolytic catalyst of carbonyl sulfur of presoma preparation with the Co-Ni-Al houghite.

3. method according to claim 1 is characterized in that: the ultrasonic wave subsidiary conditions of described steps A and B are: adopt the conventional ultrasound instrument, and the control temperature is that 30 ℃, frequency are 28 or 40KHz.

4. method according to claim 1 is characterized in that: the water of described steps A is distilled water.

5. method according to claim 1 is characterized in that: the impregnating agent of described step B is NaOH and/or Na ₂CO ₃Solution.

6. method according to claim 5 is characterized in that: the impregnating agent preferred concentration of described step B is that the NaOH solution of 3.5mol/L is or/and concentration is the Na of 1mol/L ₂CO ₃Solution.

7. method according to claim 1 is characterized in that: can continue regeneration at least three times behind the described regenerated catalyst inactivation that obtains again.

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