CN105582962B - A kind of MnOx/TiO2The regeneration method of based low-temperature denitration catalyst - Google Patents

Abstract

The invention discloses a method for regenerating _MnOx / _TiO2- based low-temperature denitration catalysts, which includes the following steps: blowing the catalyst monomer with high-pressure air, and then impregnating the catalyst in deionized water under the action of ultrasonic waves to remove impurities and soluble The material is dried, and then the obtained catalyst is put into the activation solution for activation treatment, and then it is successively subjected to microwave drying, roasting in a muffle furnace and ultraviolet irradiation treatment to obtain a regenerated SCR denitrification catalyst. The invention solves the problem of regeneration of _MnOx / _TiO2- based low-temperature denitration catalyst after deactivation, and is suitable for catalysts deactivated to different degrees. The deactivation activity of the obtained regenerated denitration catalyst can reach 97%; and the consumption of activation solution can be saved; The Mn-Ti catalyst sol prepared by the gel method can make the active component loaded firmly and improve the denitrification effect; at the same time, the activity and anti-poisoning ability of the regenerated catalyst can be improved by ultraviolet irradiation treatment.

Description

A kind of regeneration method of MnOx/TiO2 based low temperature denitration catalyst

technical field

The invention belongs to the technical field of deactivated catalyst regeneration, and in particular relates to a regeneration method of an _MnOx / _TiO2 -based low-temperature denitrification catalyst.

Background technique

Nitrogen oxides (NO _x ) are one of the main air pollutants, which seriously endanger the production and life of human beings and cause huge pollution to the ecological environment, which mainly includes damage to plants and poisonous effects on the human body, as well as the formation of photochemical smog , acid rain and the destruction of the ozone layer are major problems in air pollution control.

Now many domestic and foreign power plants adopt selective catalytic reduction (SCR) denitrification technology to meet the increasingly stringent nitrogen oxide emission standards. VW(Mo)-Ti series catalyst is the most widely used denitrification catalyst in the industry, and it has a high denitrification activity in the temperature range of 300-400 °C. Therefore, it needs to be installed before desulfurization and dust removal. At this time, high concentration of SO ₂ and dust will deactivate the catalyst and affect the life of the catalyst. If the SCR device is placed after desulfurization and dust removal, the temperature of the flue gas may drop below 200°C, so it is necessary to develop a catalyst with low temperature activity. In recent years, manganese-based (MnO _x ) catalysts are the research focus of SCR low-temperature denitrification technology.

In the long-term actual industrial application, a small amount of SO ₂ in the low temperature area will also reduce the denitrification efficiency of the honeycomb catalyst. However, in the denitrification system, the SCR catalyst can account for 50% of the total operating cost. If the deactivated Catalyst disposal not only increases the cost of catalyst utilization, but also pollutes the environment. Therefore, it is necessary to study catalyst regeneration.

Contents of the invention

The purpose of the present invention is to provide a regeneration method of _MnOx / _TiO2 -based low-temperature denitrification catalyst, which involves simple process flow, convenient operation and low cost, and the destocking activity of the obtained regenerated catalyst can recover about 95% of the original efficiency, and The active components are firmly loaded, have strong denitrification effect and anti-poisoning ability, and are suitable for popularization and application.

In order to achieve the above object, the technical scheme adopted in the present invention is:

A kind of regeneration method of _MnOx / _TiO2 base low-temperature denitration catalyst, comprises the following steps:

1) Purging and deactivating the MnO _x /TiO ₂ -based low-temperature denitration catalyst with dry compressed air, and then immersing it in water under ultrasonic vibration conditions to remove impurities and soluble substances on the surface of the denitration catalyst, and then drying;

2) immersing the deactivated MnO _x /TiO ₂ -based low-temperature denitration catalyst treated in step 1) in the activation solution for activation treatment;

3) heating the deactivated MnO _x /TiO ₂ -based low-temperature denitration catalyst that has been activated in step 2) using microwave technology;

4) placing the dried product obtained in step 3) in a muffle furnace for roasting;

5) The calcined product obtained in step 4) is irradiated with ultraviolet light to obtain a regenerated denitration catalyst.

In the above solution, the pressure of the dry compressed air in step 1) is 1-3KPa, and the purging time is 30-120min.

In the above scheme, the ultrasonic power used in the ultrasonic vibration condition in step 1) is 300-600W, and the processing time is 60-180min.

In the above scheme, the activation solution described in step 2) is the active sol of the Mn-Ti component, which is prepared from polyethylene glycol, tetrabutyl titanate, manganese acetate, absolute ethanol, water, and glacial acetic acid; Its preparation method includes the following steps: first add polyethylene glycol, tetrabutyl titanate, absolute ethanol, and manganese acetate into a three-necked flask and stir vigorously for 1 to 2 hours, then dissolve them in water, and add them dropwise to the mixed solution. Stir for 2-3 hours to obtain the active sol of the Mn-Ti component.

In the above scheme, the activation treatment time in step 2) is 2 to 24 hours.

In the above scheme, the mass ratio of each component in the activation solution is: polyethylene glycol is 3-8wt%, tetrabutyl titanate is 5-15wt%, manganese acetate is 1-10%, anhydrous The content of ethanol is 40-60wt%, and that of deionized water is 20-30wt%. Then, glacial acetic acid is used to adjust the pH value of the activation solution to 2-4.

In the above scheme, the microwave power used in the microwave technology described in step 3) is 400-1400W, and the drying time is 5-20min.

In the above scheme, the calcination temperature in step 4) is 400-600° C. for 2-4 hours.

In the above solution, the wavelength of ultraviolet light used in the ultraviolet light irradiation treatment in step 5) is in the medium wave range (290-315nm), and the treatment time is 30-120min.

In the above solution, the MnO _x in the MnO _x /TiO ₂ -based low-temperature denitration catalyst exists in the form of one or more of MnO, MnO ₂ , Mn ₂ O ₃ , and Mn ₃ O ₄ .

Preferably, the MnO _x /TiO ₂ -based low-temperature denitration catalyst is a monolithic MnO _x /TiO ₂ -based low-temperature denitration catalyst.

The beneficial effects of the present invention are:

1) The present invention effectively solves the problem of regeneration of MnO _x /TiO ₂ -based low-temperature catalyst after deactivation, and helps to solve the problem of application and cost of low-temperature catalyst in actual production.

2) The present invention is applicable to different degrees of deactivated MnO _x /TiO ₂ -based low-temperature catalysts, and can ensure that the deactivation activity of the regenerated catalyst reaches more than 95%.

3) The cleaning process of the present invention uses deionized water to reduce the loss of active substances, and separates the steps of cleaning and reloading active substances, which is beneficial to save the amount of active liquid.

4) The active sol of the Mn-Ti component prepared by the sol-gel method in the present invention can make the loading of the active component more firm, the specific surface area is larger, and the denitrification effect is better.

5) The present invention adopts microwave heating, saves heating time, and can increase the firmness of catalyst loading; adopts ultraviolet light irradiation treatment, can improve the activity and anti-poisoning ability of the regenerated catalyst.

Detailed ways

In order to better understand the present invention, the content of the present invention is further illustrated below in conjunction with the examples, but the present invention is not limited to the following examples.

The following examples are not specifically described, and the reagents used are commercially available chemical reagents or industrial products.

In the following examples, the activation solution is the active sol of the Mn-Ti component, which is prepared from polyethylene glycol, tetrabutyl titanate, manganese acetate, dehydrated alcohol, water, and glacial acetic acid; its preparation method It includes the following steps: first add polyethylene glycol, tetrabutyl titanate, absolute ethanol, and manganese acetate into a three-necked flask and stir vigorously for 1 to 2 hours to obtain a uniform mixture, then dissolve glacial acetic acid in water, and add it dropwise In the resulting mixture, continue to stir for 2 to 3 hours.

In the following examples, the preparation method of the deactivated _MnOx / _TiO2- based low-temperature denitration catalyst comprises the following steps: using manganese acetate as a manganese precursor, and tetrabutyl titanate as a titanium precursor, wherein manganese acetate and tetratitanate The amount of butyl ester added is based on the introduced manganese and titanium elements respectively. Dissolve tetrabutyl titanate and manganese acetate in absolute ethanol, adjust the pH of the solution to 2-4 with glacial acetic acid, and then add distilled water drop by drop. Mix and stir for 2 hours to obtain a sol, in which the mass ratio of tetrabutyl titanate, manganese acetate, absolute ethanol, and water is 17:5:79:40; then impregnate the honeycomb ceramics in the above sol, and then dry at 110°C, 500 ℃ roasting, and then repeated impregnation, drying, and roasting until the loading of active components in the honeycomb ceramics reached 15%, to obtain a MnO _x /TiO ₂ -based low-temperature denitration catalyst (monolithic MnO _x /TiO ₂ -based low-temperature denitration catalyst); Deactivated in poisoned flue gas, MnO _x /TiO ₂ -based low-temperature denitrification catalysts were obtained, and the denitrification rates were 37%, 42%, and 49%, respectively.

Example 1

A method for regenerating a MnO _x /TiO ₂ -based low-temperature denitration catalyst, aimed at a deactivated MnO _x /TiO ₂ -based low-temperature denitration catalyst with a denitration rate of 37%, specifically comprising the following steps:

1) Use dry compressed air to purge the deactivated MnO _x /TiO ₂ -based low-temperature denitrification catalyst. The pressure of the compressed air is 1KPa, and the purge time is ₇₀ minutes _; The low-temperature denitrification catalyst was immersed in deionized water for 120 minutes to remove other impurities and soluble substances on the surface of the catalyst, and then dried;

2) Immerse the deactivated _MnOx / _TiO2- based low-temperature denitration catalyst treated in step 1) into the activation solution (active sol of the Mn-Ti component) for activation treatment, and the immersion activation treatment time is 10 hours; wherein the activation solution It is prepared from the following components according to the following mass ratio: the mass percentage of each component is 5 wt% of polyethylene glycol, 9 wt% of tetrabutyl titanate, 1.5 wt% of manganese acetate, and 59.5 wt% of absolute ethanol wt%, deionized water is 25wt%; then adopt glacial acetic acid to adjust the pH value of the sol to 3;

3) The catalyst obtained after the treatment in step 2) is heated and dried by microwave technology for 10 minutes, and the microwave power used is 800W;

4) Put the dried product obtained in step 3) into a muffle furnace and heat it to 400°C for 4 hours;

5) The product obtained in step 4) is irradiated with ultraviolet light for 90 minutes, and the wavelength of the ultraviolet light used is in the mid-wave range (290-315nm) to obtain a regenerated denitration catalyst.

Comparative example 1

A regeneration method for a denitration catalyst, the regeneration steps of which are roughly the same as in Example 1, except that the ultraviolet light irradiation described in Step 5) of Example 1 is not used.

Example 2

A method for regenerating a MnO _x /TiO ₂ -based low-temperature denitration catalyst, aimed at a deactivated MnO _x /TiO ₂ -based low-temperature denitration catalyst with a denitration rate of 42%, specifically comprising the following steps:

1) Use dry compressed air to purge the deactivated MnO _x /TiO ₂ -based low-temperature denitrification _catalyst . The pressure of the compressed air is 2KPa, and the purge time is ₆₀ minutes; The low-temperature denitrification catalyst was immersed in deionized water for 90 minutes to remove other impurities and soluble substances on the surface of the catalyst, and then dried;

2) Immerse the deactivated _MnOx / _TiO2- based low-temperature denitration catalyst treated in step 1) into the activation solution (active sol of the Mn-Ti component) for activation treatment, and the immersion activation treatment time is 15 hours; wherein the activation solution It is prepared from the following components according to the following mass ratio: the mass percentage of each component is 6wt% of polyethylene glycol, 10wt% of tetrabutyl titanate, 3wt% of manganese acetate, and 57wt% of absolute ethanol , deionized water is 24wt%; then adopt glacial acetic acid to adjust the pH value of the sol to 4;

3) The catalyst obtained after the treatment in step 2) is heated and dried by microwave technology for 15 minutes, and the microwave power used is 600W;

4) Put the dried product obtained in step 3) into a muffle furnace and heat it to 500°C for 2 hours;

5) The product obtained in step 4) is irradiated with ultraviolet light for 120 minutes, and the wavelength of ultraviolet light used is in the mid-wave range (290-315nm) to obtain a regenerated denitration catalyst.

Comparative example 2

A regeneration method for a denitration catalyst, the regeneration steps of which are roughly the same as in Example 2, except that the ultraviolet light irradiation described in Step 5) of Example 2 is not used.

Example 3

A method for regenerating a MnO _x /TiO ₂ -based low-temperature denitration catalyst, aimed at a deactivated MnO _x /TiO ₂ -based low-temperature denitration catalyst with a denitration rate of 49%, specifically comprising the following steps:

1) Use dry compressed air to purge the deactivated MnO _x /TiO ₂ -based low-temperature denitrification _catalyst . The pressure of the compressed air is 3KPa, and the purge time is _40min ; The low-temperature denitrification catalyst was immersed in deionized water for 180 minutes to remove other impurities and soluble substances on the surface of the catalyst, and then dried;

2) Immerse the deactivated _MnOx / _TiO2- based low-temperature denitration catalyst treated in step 1) into the activation solution (active sol of the Mn-Ti component) for activation treatment, and the immersion activation treatment time is 20 hours; wherein the activation solution It is prepared from the following components according to the following mass ratio: the mass percentage of each component is 7wt% of polyethylene glycol, 11wt% of tetrabutyl titanate, 4wt% of manganese acetate, and 51wt% of absolute ethanol , deionized water is 27wt%; then adopt glacial acetic acid to adjust the PH value of the sol to 2;

3) The catalyst obtained after the treatment in step 2) is heated and dried by microwave technology for 15 minutes, and the microwave power used is 600W;

4) Put the dried product obtained in step 3) into a muffle furnace and heat it to 600°C for 2 hours;

5) The product obtained in step 4) is irradiated with ultraviolet light for 50 minutes, and the wavelength of the ultraviolet light used is in the middle wavelength range (290-315nm) to obtain a regenerated denitration catalyst.

Comparative example 3

A regeneration method for a denitration catalyst, the regeneration steps of which are roughly the same as in Example 3, except that the ultraviolet light irradiation described in step 5) of Example 3 is not used.

activity evaluation

The denitration activity tests were carried out on the regenerated denitration catalysts obtained in Examples 1-3 and Comparative Examples 1-3 respectively, and the results are shown in Table 1.

Table 1 Denitrification activity test results

The above results show that the regeneration effect described in Example 2 is the best, and the denitrification rate of the regenerated catalyst obtained by the regeneration method of the invention can reach more than 85%.

The above descriptions are for exemplary embodiments, but should not be construed as limiting the present invention. For those of ordinary skill in the art, other changes or changes in different forms can be made on the basis of the above description. It is not necessary and impossible to list all the implementation manners here. And the obvious changes or changes derived therefrom are still within the scope of protection of the present invention.

Claims (9)

1. a kind of MnO _x / _TiO The regeneration method of base low-temperature denitration catalyst, is characterized in that, comprises the following steps: 1) Purging and deactivating the MnO _x /TiO ₂ -based low-temperature denitration catalyst with dry compressed air, and then immersing it in water under ultrasonic vibration conditions to remove impurities and soluble substances on the surface of the denitration catalyst, and then drying; 2) immersing the deactivated MnO _x /TiO ₂ -based low-temperature denitration catalyst treated in step 1) in the activation solution for activation treatment; 3) heating the deactivated MnO _x /TiO ₂ -based low-temperature denitration catalyst that has been activated in step 2) using microwave technology; 4) placing the dried product obtained in step 3) in a muffle furnace for roasting; 5) subjecting the calcined product obtained in step 4) to ultraviolet light irradiation treatment to obtain a regenerated denitration catalyst; The activation solution described in the step 2) is the active sol of the Mn-Ti component, which is prepared from polyethylene glycol, tetrabutyl titanate, manganese acetate, dehydrated alcohol, water, and glacial acetic acid; its preparation method includes The following steps: first add polyethylene glycol, tetrabutyl titanate, absolute ethanol, and manganese acetate into a three-necked flask and stir vigorously for 1 to 2 hours to obtain a uniform mixture, then dissolve glacial acetic acid in water, and add the obtained mixture dropwise. In the mixed solution, the stirring is continued for 2-3 hours to obtain the active sol of the Mn-Ti component. 2. The regeneration method according to claim 1, characterized in that the pressure of the dry compressed air in step 1) is 1-3KPa, and the purging time is 30-120min. 3. The regeneration method according to claim 1, characterized in that the ultrasonic power used in the ultrasonic vibration in step 1) is 300-600W, and the processing time is 60-180min. 4. The regeneration method according to claim 1, characterized in that, the mass ratio of each component in the activation solution is: polyethylene glycol is 3-8wt%, tetrabutyl titanate is 5-15wt% %, 1-10 wt% of manganese acetate, 40-60 wt% of absolute ethanol, and 20-30 wt% of deionized water; then adjust the pH value of the activation solution to 2-4 with glacial acetic acid. 5. The regeneration method according to claim 1, characterized in that the activation treatment time in step 2) is 2-24 hours. 6. The regeneration method according to claim 1, characterized in that the microwave power used in the microwave technology in step 3) is 400-1400W, and the drying time is 5-20min. 7. The regeneration method according to claim 1, characterized in that the calcination temperature in step 4) is 400-600°C for 2-4 hours. 8 . The regeneration method according to claim 1 , wherein the wavelength of ultraviolet light used in the ultraviolet light irradiation treatment in step 5) is in the medium wave range, and the treatment time is 30-120 minutes. 9. The regeneration method according to claim 1, characterized in that, the MnO _x in the MnO _x /TiO ₂ -based low-temperature denitration catalyst exists in the form of MnO, MnO ₂ , Mn ₂ O ₃ , Mn ₃ O ₄ one or several.