阅读说明：本技术 Scr脱硝催化剂干法深度清洁的工艺方法 (Process method for deep cleaning of SCR denitration catalyst by dry method ) 是由 吴凡 史伟伟 郑志海 方海峰 杨晓良 于 2020-08-03 设计创作，主要内容包括：本发明涉及SCR脱硝催化剂干法深度清洁的工艺方法,包括以下工艺步骤：1)初步除尘,将SCR脱硝催化剂进行表面除灰,进行一吹二吸清灰的方式；2)等离子体清洗,建立建立等离子气氛,将步骤1)处理后的SCR脱硝催化剂置于等离子体中,对其进行等离子体清洗；3)固体脱硫脱硝,使用固体脱硫脱硝剂对步骤2)中得到的SCR脱硝催化剂进行再次清洗；4)配置含有偏钒酸铵和仲钨酸铵的催化剂再生活性液；5)采用雾化喷雾方法在步骤3)清洗后的SCR脱硝催化剂表面喷涂步骤4)配置的催化剂再生活性液；6)干燥和烧结,将步骤5)中得到的喷涂有催化剂活性物资的SCR脱硝催化剂进行干燥和烧结。(The invention relates to a process method for deep cleaning of an SCR denitration catalyst by a dry method, which comprises the following process steps: 1) preliminary dust removal, namely performing surface dust removal on the SCR denitration catalyst, and performing a one-blowing and two-suction dust removal mode; 2) plasma cleaning, namely establishing a plasma atmosphere, placing the SCR denitration catalyst treated in the step 1) into plasma, and performing plasma cleaning on the SCR denitration catalyst; 3) solid desulfurization and denitrification, namely cleaning the SCR denitration catalyst obtained in the step 2) again by using a solid desulfurization and denitrification agent; 4) preparing catalyst regeneration active liquid containing ammonium metavanadate and ammonium paratungstate; 5) spraying the catalyst regeneration active liquid prepared in the step 4) on the surface of the SCR denitration catalyst cleaned in the step 3) by adopting an atomization spraying method; 6) drying and sintering, namely drying and sintering the SCR denitration catalyst sprayed with the catalyst active material obtained in the step 5).)

The process method for the dry-process deep cleaning of the SCR denitration catalyst is characterized by comprising the following process steps:

1) preliminary dust removal, namely performing surface dust removal on the SCR denitration catalyst, and performing a one-blowing and two-sucking mode by combining negative pressure dust suction and positive pressure dust blowing;

2) plasma cleaning, namely establishing a plasma atmosphere, placing the SCR denitration catalyst treated in the step 1) into plasma, and performing plasma cleaning on the SCR denitration catalyst; wherein the vacuum degree of the plasma atmosphere is 100-500 Pa;

3) solid desulfurization and denitrification, namely cleaning the SCR denitration catalyst obtained in the step 2) again by using a solid desulfurization and denitrification agent;

4) preparing catalyst regeneration active liquid containing ammonium metavanadate and ammonium paratungstate;

5) spraying the catalyst regeneration active liquid prepared in the step 4) on the surface of the SCR denitration catalyst cleaned in the step 3) by adopting an atomization spraying method;

6) drying and sintering, namely drying and sintering the SCR denitration catalyst sprayed with the catalyst active material obtained in the step 5).

2. The process method for the dry deep cleaning of the SCR denitration catalyst according to claim 1, wherein in the step 2), the method for establishing the plasma atmosphere comprises the following steps: under the vacuum condition, forming an electric field between two polar plates and introducing working gas, wherein the working gas is Ar and H2; as the degree of vacuum increases, the gas becomes thinner and the distance between molecules and the free movement distance of molecules or ions becomes longer, and they collide with each other to form plasma under the action of an electric field.

3. The process method for the dry deep cleaning of the SCR denitration catalyst according to claim 2, wherein the vacuum degree of the plasma atmosphere is 50-1000 Pa.

4. The process method for the dry deep cleaning of the SCR denitration catalyst according to claim 3, wherein the working gas can be one or more of Ar, N2, O2, H2 and CF 4.

5. The process for dry deep cleaning of an SCR denitration catalyst according to claim 1, wherein the atomization spraying method in step 5) is a two-fluid atomization spraying method, that is, the regeneration active liquid and compressed air are sprayed together through a two-fluid nozzle to coat the surface of the catalyst.

6. The process method for the dry deep cleaning of the SCR denitration catalyst according to claim 1, wherein in the step 4), the catalyst regeneration active liquid further comprises a penetrating agent, a surfactant, a complexing agent, oxalic acid and deionized water;

the preparation is to uniformly mix all the components in the regenerated active liquid to obtain the catalyst regenerated active liquid.

7. The process method for the dry deep cleaning of the SCR denitration catalyst according to claim 1, wherein the solid desulfurization and denitration agent in the step 3) comprises a solid desulfurization and denitration catalyst and an alkaline substance;

the mass ratio of the alkaline substance to the solid desulfurization and denitrification catalyst is 100: (0.2-8.0).

8. The process method for the dry deep cleaning of the SCR denitration catalyst according to claim 7, wherein the preparation method of the solid desulfurization denitration catalyst comprises the following steps: dispersing more than one copper salt accounting for 15.0-396.0 parts by mass and/or more than one manganese salt accounting for 32.0-48.0 parts by mass, KMnO4 accounting for 10.0-30 parts by mass and sodium carbonate solution accounting for 100.0-900.0 parts by mass into a solvent to form slurry, stirring, filtering, washing, drying and grinding the product, and then burning the product in an air atmosphere at 300-350 ℃.

9. The process method for the dry deep cleaning of the SCR denitration catalyst according to claim 8, wherein the alkaline substance is magnesium oxide, magnesium hydroxide, magnesium carbonate, calcium oxide, calcium hydroxide and/or calcium carbonate.

10. The process method for the dry deep cleaning of the SCR denitration catalyst according to claim 9, wherein the preparation method of the solid desulfurization and denitration agent comprises the following steps: mixing the following components in a mass ratio of 100.0: (0.2-8.0) adding water, kneading, extruding, and drying at 50-100 ℃ for 0.5-2.0 hours to obtain the catalyst.

Technical Field

The invention relates to the technical field of catalyst cleaning, in particular to a process method for deep dry cleaning of an SCR denitration catalyst.

Background

The flue gas denitration transformation of the thermal power plant adopting the SCR technology in large scale in China begins in 2010, and the earliest flue gas denitration system can be traced to 2008. The chemical life of the vanadium-titanium catalyst used for SCR flue gas denitration is 20000-24000 hours, and the mechanical life is 10 years. However, in practical application, due to the influence of product quality and operating environment, the catalyst capable of reaching the theoretical life is few, and generally, after 2-3 years of use, the activity is reduced and cleaning and regeneration are needed, and after 6-7 years, the catalyst needs to be updated, so that tens of thousands of tons of waste denitration catalysts per year are generated in recent years. The letter No. 2014 990 of the Ministry of environmental protection of China, which is sold at 8.5.2014, lists the scrapped vanadium-titanium catalyst as dangerous solid waste and is numbered HW 50.

The SCR denitration catalyst mostly takes TiO2 as a carrier, and V2O5, V2O5-WO3 or V2O5-MoO3 as an active main component, and the SCR denitration catalyst generally has three types, namely a honeycomb type, a plate type and a corrugated type. Studies have shown that the causes of deactivation of SCR catalysts are mainly: catalyst poisoning (alkali metal poisoning, arsenic poisoning, mercury poisoning, etc.), sulfate plugging, fly ash plugging, etc.

At present, the catalyst regeneration technology is relatively mature, the conventional cleaning regeneration technology can mostly meet the application of the existing denitration system in the power industry, however, as the waste catalyst belongs to dangerous waste, the conventional industrial regeneration needs to transfer the procedure approval (the procedure handling time is often uncontrollable) through the danger waste in a transprovincial way, and the time and the labor are wasted through the back-and-forth transportation. In addition, the corrugated plate catalyst cannot be treated by means of conventional water washing, acid washing and the like due to a special forming process, and has certain limitation.

Disclosure of Invention

The invention aims to provide a dry-method deep cleaning process method for an SCR denitration catalyst, which aims to solve the technical problem of deep cleaning of the catalyst under the action of no liquid-phase medium.

The process method for the dry-process deep cleaning of the SCR denitration catalyst is realized by the following steps:

the process method for the dry deep cleaning of the SCR denitration catalyst comprises the following process steps:

1) preliminary dust removal, namely performing surface dust removal on the SCR denitration catalyst, and performing a one-blowing and two-sucking mode by combining negative pressure dust suction and positive pressure dust blowing;

2) plasma cleaning, namely establishing a plasma atmosphere, placing the SCR denitration catalyst treated in the step 1) into plasma, and performing plasma cleaning on the SCR denitration catalyst; wherein the vacuum degree of the plasma atmosphere is 100-500 Pa;

3) solid desulfurization and denitrification, namely cleaning the SCR denitration catalyst obtained in the step 2) again by using a solid desulfurization and denitrification agent;

4) preparing catalyst regeneration active liquid containing ammonium metavanadate and ammonium paratungstate;

5) spraying the catalyst regeneration active liquid prepared in the step 4) on the surface of the SCR denitration catalyst cleaned in the step 3) by adopting an atomization spraying method;

6) drying and sintering, namely drying and sintering the SCR denitration catalyst sprayed with the catalyst active material obtained in the step 5).

Further, in step 2), the method for establishing the plasma atmosphere comprises the following steps: under the vacuum condition, forming an electric field between two polar plates and introducing working gas, wherein the working gas is Ar and H2; as the degree of vacuum increases, the gas becomes thinner and the distance between molecules and the free movement distance of molecules or ions becomes longer, and they collide with each other to form plasma under the action of an electric field.

Further, the vacuum degree of the plasma atmosphere is 50-1000 Pa.

Further, the working gas can adopt one or more of Ar, N2, O2, H2 and CF4 for mixing.

Further, the atomization spraying method in the step 5) is a two-fluid atomization spraying method, namely the regeneration active liquid and compressed air are sprayed together through a two-fluid nozzle to be coated on the surface of the catalyst;

further, in the step 4), the catalyst regeneration active liquid further comprises a penetrating agent, a surfactant, a complexing agent, oxalic acid and deionized water;

the preparation is to uniformly mix all the components in the regenerated active liquid to obtain the catalyst regenerated active liquid.

Further, the solid desulfurization and denitrification agent in the step 3) comprises a solid desulfurization and denitrification catalyst and an alkaline substance;

the mass ratio of the alkaline substance to the solid desulfurization and denitrification catalyst is 100: (0.2-8.0).

Further, the preparation method of the solid desulfurization and denitrification catalyst comprises the following steps: dispersing more than one copper salt accounting for 15.0-396.0 parts by mass and/or more than one manganese salt accounting for 32.0-48.0 parts by mass, KMnO4 accounting for 10.0-30 parts by mass and sodium carbonate solution accounting for 100.0-900.0 parts by mass into a solvent to form slurry, stirring, filtering, washing, drying and grinding the product, and then burning the product in an air atmosphere at 300-350 ℃.

Further, the alkaline substance is magnesium oxide, magnesium hydroxide, magnesium carbonate, calcium oxide, calcium hydroxide and/or calcium carbonate.

Further, the preparation method of the solid desulfurization and denitrification agent comprises the following steps: mixing the following components in a mass ratio of 100.0: (0.2-8.0) adding water, kneading, extruding, and drying at 50-100 ℃ for 0.5-2.0 hours to obtain the catalyst.

Compared with the prior art, the embodiment of the invention has the following beneficial effects: the plasma cleaning method is applied to cleaning of the failed SCR denitration catalyst, so that substances adhered to the surface of the catalyst, especially ammonium sulfate substances, are thoroughly cleaned, the active site and the specific surface area of the catalyst are greatly recovered, the subsequent wastewater treatment step is omitted compared with the existing acid cleaning method, and the cleaning efficiency is higher; cleaning again by matching with a desulfurization and denitrification agent, taking a calcium-containing or magnesium-containing alkaline substance as a carrier, and adding a catalyst containing manganese and copper, so that the desulfurization and denitrification efficiency is obviously improved, and the SCR denitrification catalyst is deeper and cleaner; then, converting the regenerated active ingredients in the regenerated active liquid into atomized particles by adopting an atomization spraying method (such as a gas-liquid two-phase two-fluid atomization spraying method specifically), so that the atomized particles are coated on the surface of the cleaned catalyst in a highly dispersed form; the subsequent hot air drying and calcining processes (which may be carried out in an air atmosphere at a high temperature, for example) then convert the sprayed active material into an active material of an oxide-constituting catalyst. The regeneration process provided by the invention has the advantages of high efficiency, low cost and strong environmental protection, does not have the problem of treatment of regeneration wastewater, and completely avoids secondary pollution.

Detailed Description

The present invention will now be described in further detail.

The process method for the dry deep cleaning of the SCR denitration catalyst comprises the following process steps:

1) preliminary dust removal, namely performing surface dust removal on the SCR denitration catalyst, and performing a one-blowing and two-sucking mode by combining negative pressure dust suction and positive pressure dust blowing;

2) plasma cleaning, namely establishing a plasma atmosphere, placing the SCR denitration catalyst treated in the step 1) into plasma, and performing plasma cleaning on the SCR denitration catalyst; wherein the vacuum degree of the plasma atmosphere is 100-500 Pa;

3) solid desulfurization and denitrification, namely cleaning the SCR denitration catalyst obtained in the step 2) again by using a solid desulfurization and denitrification agent;

4) preparing catalyst regeneration active liquid containing ammonium metavanadate and ammonium paratungstate;

5) spraying the catalyst regeneration active liquid prepared in the step 4) on the surface of the SCR denitration catalyst cleaned in the step 3) by adopting an atomization spraying method;

6) drying and sintering, namely drying and sintering the SCR denitration catalyst sprayed with the catalyst active material obtained in the step 5).

In the step 2), the method for establishing the plasma atmosphere comprises the following steps: under the vacuum condition, forming an electric field between two polar plates and introducing working gas, wherein the working gas is Ar and H2; as the degree of vacuum increases, the gas becomes thinner and the distance between molecules and the free movement distance of molecules or ions becomes longer, and they collide with each other to form plasma under the action of an electric field.

The vacuum degree of the plasma atmosphere is 50-1000 Pa. Preferably, 100-500Pa is used.

The working gas can adopt one or more of Ar, N2, O2, H2 and CF4 for mixing. For example, the working gases are Ar and H2.

The atomization spraying method in the step 5) is a two-fluid atomization spraying method, namely the regeneration active liquid and compressed air are sprayed out together through a two-fluid nozzle and coated on the surface of the catalyst;

in the step 4), the catalyst regeneration active liquid also comprises a penetrating agent, a surfactant, a complexing agent, oxalic acid and deionized water; the preparation is to uniformly mix all the components in the regenerated active liquid to obtain the catalyst regenerated active liquid.

Wherein, the penetrating agent is JFC, the surfactant is OP-10, and the complexing agent is polyvinyl alcohol. For example, the regenerative active liquid includes:

0.8 to 1.1 wt% of ammonium metavanadate,

5.5 to 15.6 wt% of ammonium paratungstate,

0.05 to 1 weight percent of penetrating agent,

0.05 to 1 wt% of a surfactant,

0.05 to 1wt percent of complexing agent,

oxalic acid 5.2 to 8.4 wt%, and

the balance of deionized water.

The solid desulfurization and denitrification agent in the step 3) comprises a solid desulfurization and denitrification catalyst and an alkaline substance;

the mass ratio of the alkaline substance to the solid desulfurization and denitrification catalyst is 100: (0.2-8.0).

The preparation method of the solid desulfurization and denitrification catalyst comprises the following steps: dispersing more than one copper salt accounting for 15.0-396.0 parts by mass and/or more than one manganese salt accounting for 32.0-48.0 parts by mass, KMnO4 accounting for 10.0-30 parts by mass and a sodium carbonate solution accounting for 100.0-900.0 parts by mass into a solvent to form slurry, stirring, filtering, washing, drying and grinding the product, and then burning the product in an air atmosphere at 300-350 ℃.

The copper salt is copper sulfate pentahydrate and/or copper nitrate trihydrate.

The manganese salt is manganese sulfate monohydrate and/or manganese nitrate tetrahydrate.

The alkaline substance is magnesium oxide, magnesium hydroxide, magnesium carbonate, calcium oxide, calcium hydroxide and/or calcium carbonate.

The preparation method of the solid desulfurization and denitrification agent comprises the following steps: kneading and extruding 100.0 parts by mass of an alkaline substance, 0.2-8.0 parts by mass of a desulfurization and denitrification catalyst and 0-20 parts by mass of water to prepare a strip, and drying at 50-100 ℃ for 0.5-2.0 hours to obtain the catalyst.

According to the invention, the plasma cleaning method is applied to cleaning of the failure SCR denitration catalyst, so that substances adhered to the surface of the catalyst, especially ammonium sulfate substances, are thoroughly cleaned, the activity site and the specific surface area of the catalyst are greatly recovered, compared with the existing acid cleaning method, the subsequent wastewater treatment step is omitted, and the cleaning efficiency is higher; cleaning again by matching with a desulfurization and denitrification agent, taking a calcium-containing or magnesium-containing alkaline substance as a carrier, and adding a catalyst containing manganese and copper, so that the desulfurization and denitrification efficiency is obviously improved, and the SCR denitrification catalyst is deeper and cleaner; then, converting the regenerated active ingredients in the regenerated active liquid into atomized particles by adopting an atomization spraying method (such as a gas-liquid two-phase two-fluid atomization spraying method specifically), so that the atomized particles are coated on the surface of the cleaned catalyst in a highly dispersed form; the subsequent hot air drying and calcining processes (which may be carried out in an air atmosphere at a high temperature, for example) then convert the sprayed active material into an active material of an oxide-constituting catalyst. The regeneration process provided by the invention has the advantages of high efficiency, low cost and strong environmental protection, does not have the problem of treatment of regeneration wastewater, and completely avoids secondary pollution.

The development of the dry-method deep cleaning technology can greatly reduce the regeneration production cost, can make up for the defects of long construction period and complicated process of the wet-method regeneration technology, is beneficial to strengthening daily maintenance of a denitration system in the power industry to save the cost, is imperative, and provides good application prospect for the expansion of the denitration catalyst regeneration technology.

The microcosmic specific surface area of the SCR denitration catalyst is recovered by more than 90 percent after the dry deep cleaning regeneration; the main technical indexes of the SCR denitration catalyst such as activity, ammonia escape, sulfur dioxide oxidation rate and the like are recovered by more than 90 percent after dry activation.

The above is only a preferred embodiment of the present invention, and is not intended to limit the present invention, and various modifications and changes will occur to those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.