Method for reconstructing and regenerating ship SCR (Selective Catalytic Reduction) denitration catalyst

Abstract

The invention relates to the field of secondary utilization of catalysts, in particular to a ship SCR denitration catalyst reconstruction and regeneration method which comprises the following steps: s100, pretreatment of collected ship SCR denitration catalyst solid waste, s200, chemical cleaning of the solid waste, s300, intermediate heat treatment of the solid waste, s400, activity implantation of the solid waste, s500, final heat treatment, s600, finishing and windward side reinforcement. According to the dust removal step, common dust impurities adsorbed from waste gas in the use process of the catalyst are washed away, and the catalytic efficiency of the catalyst is improved; pollutants on the surface of the catalyst are removed in a high-temperature oxidation mode, surface active components of the catalyst are reduced, the activity of the catalyst is recovered, and finally solid vanadium pentoxide is soaked in an aluminum sulfate solution and then dried, so that the surface of the regenerated SCR denitration catalyst is hardened, the compressive strength of the windward side is increased, and the resistance is enhanced; therefore, the service life of the SCR denitration catalyst in the reactor is prolonged.

Description

Technical Field

[0001] The present invention relates to the field of catalyst secondary utilization, and in particular to a method for reconstructing and regenerating a ship SCR denitration catalyst. Background Art

[0002] Ships need to consume carbon-containing fuels to provide power during operation. Carbon-containing fuels inevitably produce nitrogen oxides during combustion. Nitrogen oxides (NOx) are one of the main pollutants in the atmospheric environment. They not only form acid rain, but also cause chemical smog, which is harmful to human health. With the deepening of ecological civilization construction, more and more ships have begun to use denitrification technology to clean ship exhaust gas. Denitrification technology requires the use of SCR denitrification catalysts. SCR denitrification catalysts are a technology used to reduce the emission of nitrogen oxides (NOx) in exhaust gas. Its function is to use catalysts to promote the chemical reaction of nitrogen oxides in exhaust gas with the added reducing agent (usually urea solution or ammonia) at high temperature, converting NOx into nitrogen (N2) and water vapor (H2O) to reduce pollution to the environment. The most mature and widely used SCR denitrification catalyst is the vanadium-titanium catalyst. Since V2O5 is biologically toxic, vanadium-titanium waste SCR catalysts are hazardous solid wastes. On the other hand, tungsten, vanadium, and titanium are rare metal elements with high value, and their recycling or resource utilization has recently become a research hotspot. In the existing recycling of some waste catalysts, a few companies grind the waste catalysts after simple dust removal and mix them with new tungsten-vanadium-titanium composite powders in a certain proportion to prepare denitration catalysts. This method is very easy to accumulate harmful elements, resulting in the gradual deterioration of denitration performance, which is not worth promoting. In terms of resource utilization, since the denitration catalyst is prepared and used at high temperature, the structure is relatively stable, and conventional smelting conditions are difficult to achieve efficient decomposition of waste catalysts. Most processes combine pyrometallurgy with hydrometallurgy, and use acidic and alkaline solutions to extract valuable elements respectively. Since tungsten, molybdenum, vanadium and other elements have similar chemical properties, extraction or ion exchange methods are also used to solve their deep separation problems. Although these technologies can produce single products of tungsten, molybdenum, vanadium and titanium, they have problems such as long processes, high costs, and easy secondary pollution.

[0003] Therefore, a method for reconstructing and regenerating a ship SCR denitrification catalyst is needed to solve this problem. Summary of the invention

[0004] The object of the present invention is to provide a method for reconstructing and regenerating a ship SCR denitration catalyst, aiming to solve the problems raised in the background technology.

[0005] To achieve the above object, the present invention provides the following technical solutions:

[0006] A method for reconstructing and regenerating a ship SCR denitration catalyst, the method comprising the following steps: s100, pre-treating the collected ship SCR denitration catalyst solid waste, s200, chemical cleaning of the solid waste, s300, intermediate heat treatment of the solid waste, s400, active implantation of the solid waste, s500, final heat treatment, and s600, sorting and windward side reinforcement.

[0007] Preferably, in step s100, the pretreatment of solid waste is to grind and dedust the collected waste catalyst, and the grinding is performed using an MJW-W grading impact mill. The material is crushed by the strong impact of the high-speed rotating crushing disk and the action of centrifugal force. The crushed material moves to the grading area with the air flow, and the coarse and fine materials are separated by the adjustable grading wheel. The fine powder product is collected, and the coarse material is returned for grinding again. The collected suction powder is washed with water for dust removal, and the dust-removed powder is dried.

[0008] Preferably, the chemical cleaning of the solid waste in step s200 adopts an acidic ammonium salt vanadium precipitation method, firstly dissolving the powder collected in step s100 in an acidic environment provided by a mixed solution of sodium sulfite and sulfuric acid to obtain a soluble vanadate, reducing the vanadate and heating it to 40 to 60 degrees, adding zinc powder, introducing carbon dioxide into the vanadate solution under stirring to adjust the pH and carry out a reduction reaction, and after the reduction reaction, performing solid-liquid separation to obtain a vanadium-zinc mixed precipitate and a filtrate, and the filtrate is directly recycled for leaching vanadium-containing clinker, and the amount of zinc powder added is 0.9 to 0.96 times the theoretical amount for reducing 5-valent V to 4-valent V.

[0009] Preferably, in step S200, the obtained vanadium-zinc mixed precipitate is slurried, sulfuric acid is added to adjust the pH of the slurry, and solid-liquid separation is performed after sufficient stirring and dissolution to obtain a tetravalent vanadium precipitate and a zinc sulfate solution, the precipitate is extracted and the tetravalent vanadium precipitate is subjected to the intermediate heat treatment in step S300, and the precipitate is subjected to oxidative calcination treatment to obtain a solid vanadium pentoxide substance.

[0010] Preferably, in step s400, the active implantation of solid waste is to degrade the vanadium pentoxide obtained in step s300 by microorganisms, degrading carbon deposits and sulfur and other substances in the vanadium pentoxide into harmless substances, thereby restoring the activity of the catalyst. The microorganisms can be selected from the genus Thiobacillus, which degrades hydrogen sulfide at a temperature of 28 to 30°C. Through this process, the genus Thiobacillus itself will be reproduced, so it can be used continuously.

[0011] Preferably, in step 500, the final heat treatment is to immerse the catalyst in hot air through a hot air regeneration method, remove pollutants on the catalyst surface by high-temperature oxidation, and restore the surface active components of the catalyst. The advantages of this method are simple operation and low cost.

[0012] Preferably, in step 600, the finishing and windward surface reinforcement include preparing a reinforcement solution, which is prepared by mixing aluminum sulfate powder and deionized water in a ratio of 1:4, heating to 80 degrees, stirring at a constant temperature for 2 hours, naturally cooling to room temperature, and then vertically inserting solid vanadium pentoxide into the solution, and finally placing it in a hot air furnace for drying at 100 degrees for 30 minutes.

[0013] Beneficial effects: The dust removal step of the present invention washes away common dust impurities adsorbed from exhaust gas by the catalyst during use, thereby improving the catalytic efficiency of the catalyst; the present invention dissolves the powder in an acidic environment provided by a mixed solution of sodium sulfite and sulfuric acid to obtain soluble vanadates, thereby achieving the purpose of chemically purifying the vanadium element to separate it from the original solid waste, and obtaining tetravalent vanadium through a reduction reaction for easy subsequent treatment; the present invention pulps the vanadium-zinc mixed precipitate, extracts the precipitate, and oxidizes and calcines the tetravalent vanadium precipitate to obtain a solid vanadium pentoxide, thereby facilitating the separation of vanadium and the removal of excess waste liquid and obtaining pure vanadium pentoxide again by oxidizing the tetravalent vanadium, and then Vanadium pentoxide is degraded by microorganisms of the genus Thiobacillus, and substances such as carbon deposits and sulfur in vanadium pentoxide are degraded into harmless substances, thereby restoring the activity of the catalyst; the present invention soaks the catalyst in hot air through a hot air regeneration method, removes pollutants on the surface of the catalyst by high-temperature oxidation, and restores the surface active components of the catalyst, so that the activity of the catalyst is restored, and finally solid vanadium pentoxide is soaked in an aluminum sulfate solution and then dried, and the compression resistance and wear resistance of the aluminum sulfate after drying are utilized to harden the surface of the regenerated SCR denitration catalyst, increase the compressive strength of the windward side, and strengthen the resistance, thereby extending the service life of the SCR denitration catalyst in the reactor. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] In order to more clearly illustrate the implementation of the present invention or the technical solution in the prior art, the following briefly introduces the drawings required for the implementation or the description of the prior art. Obviously, the drawings in the following description are only exemplary, and for ordinary technicians in this field, other implementation drawings can be derived from the provided drawings without creative work.

[0015] Figure 1 It is a schematic diagram of the overall method flow of the present invention;

[0016] Figure 2 This is a flow chart of pretreatment and chemical cleaning of the present invention;

[0017] Figure 3 This is a flow chart of the intermediate heat treatment and active implantation of the present invention;

[0018] Figure 4 This is a flow chart of the final heat treatment and windward surface reinforcement of the present invention. DETAILED DESCRIPTION

[0019] The present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. Obviously, the described embodiments are only part of the embodiments of the invention, rather than all of the embodiments. In the absence of conflict, the embodiments in this application and the features in the embodiments can be combined with each other. Based on the embodiments in the invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the invention.

[0020] It should be noted that if the embodiments of the invention involve directional indications (such as up, down, left, right, front, back, etc.), the directional indications are only used to explain the relative position relationship, movement status, etc. between the components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication will also change accordingly.

[0021] In addition, "multiple" means more than two. In addition, the technical solutions between the various embodiments can be combined with each other, but it must be based on the fact that ordinary technicians in the field can implement it. When the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such combination of technical solutions does not exist and is not within the scope of protection required by the invention.

[0022] Please refer to the instruction manual Figure 1-Figure 4 A method for reconstructing and regenerating a ship SCR denitration catalyst, the method comprising the following steps: s100, pre-treating the collected ship SCR denitration catalyst solid waste, s200, chemical cleaning of the solid waste, s300, intermediate heat treatment of the solid waste, s400, active implantation of the solid waste, s500, final heat treatment, s600, sorting and windward side reinforcement.

[0023] Furthermore, in the step s100, the pretreatment of solid waste is to grind and dedust the collected waste catalyst, and the grinding is carried out using an MJW-W grading impact mill. The material is crushed by the strong impact of the high-speed rotating crushing disk and the action of centrifugal force. The crushed material moves to the grading area with the airflow, and the coarse and fine materials are separated by the adjustable grading wheel. The fine powder product is collected, and the coarse material is returned for pulverization again. The collected adsorbed powder is washed with water for dust removal, and the dust-removed powder is dried. The dust removal involves washing away ordinary dust impurities adsorbed from the exhaust gas by the catalyst during use, thereby improving the catalytic efficiency of the catalyst.

[0024] Furthermore, the chemical cleaning of the solid waste in step s200 adopts an acidic ammonium salt vanadium precipitation method. First, the powder collected in step s100 is dissolved in an acidic environment provided by a mixed solution of sodium sulfite and sulfuric acid to obtain a soluble vanadate. The vanadate is reduced and heated to 40 to 60 degrees, zinc powder is added, and carbon dioxide is introduced into the vanadate solution under stirring to adjust the pH and perform a reduction reaction. After the reduction reaction, solid-liquid separation is performed to obtain a vanadium-zinc mixed precipitate and a filtrate. The filtrate is directly recycled for leaching vanadium-containing clinker. The amount of zinc powder added is 0.9 to 0.96 times the theoretical amount of reducing 5-valent V to 4-valent V. The function of this step is to chemically purify the vanadium element to separate it from the original solid waste and convert it into vanadate, and obtain tetravalent vanadium through a reduction reaction for subsequent treatment.

[0025] Furthermore, in step S200, the obtained vanadium-zinc mixed precipitate is slurried, sulfuric acid is added to adjust the pH of the slurry, and after sufficient stirring and dissolution, solid-liquid separation is performed to obtain a tetravalent vanadium precipitate and a zinc sulfate solution. The precipitate is extracted and the tetravalent vanadium precipitate is subjected to the intermediate heat treatment in step S300, and the precipitate is oxidized and calcined to obtain a solid vanadium pentoxide. This step can separate and precipitate the purified tetravalent vanadium, facilitate the separation of vanadium, eliminate excess waste liquid, and obtain pure vanadium pentoxide again by oxidizing the tetravalent vanadium.

[0026] Furthermore, in step s400, the active implantation of solid waste is to degrade the vanadium pentoxide obtained in step s300 by microorganisms, degrading carbon deposits and sulfur and other substances in the vanadium pentoxide into harmless substances, thereby restoring the activity of the catalyst. The microorganisms can be selected from the genus Thiobacillus, which degrades hydrogen sulfide at a temperature of 28 to 30°C. Through this process, the genus Thiobacillus itself will be reproduced, so it can be used continuously.

[0027] Furthermore, in step 500, the final heat treatment is to immerse the catalyst in hot air through a hot air regeneration method, remove pollutants on the catalyst surface by high-temperature oxidation, and restore the surface active components of the catalyst. The advantages of this method are simple operation and low cost. When used, adsorbents and active substances gradually accumulate on the catalyst surface, so that the catalyst activity gradually decreases, the pollutants on the catalyst surface are removed, and the catalyst activity is restored.

[0028] Furthermore, in step 600, the finishing and windward surface reinforcement include preparing a reinforcement solution, which is prepared by mixing aluminum sulfate powder and deionized water in a ratio of 1:4, heating to 80 degrees, stirring at a constant temperature for 2 hours, and naturally cooling to room temperature, and then vertically inserting solid vanadium pentoxide into the solution, and finally placing it in a hot air furnace for drying at 100 degrees for 30 minutes. This step utilizes the compressive resistance and wear resistance of aluminum sulfate after drying to harden the surface of the regenerated SCR denitration catalyst, increase the compressive strength of the windward surface, and enhance the resistance, thereby extending the service life of the SCR denitration catalyst in the reactor.

[0029] First, the collected waste catalyst is ground into powder using an MJW-W graded impact mill, and the collected adsorbed powder is washed with water for dust removal, and ordinary dust impurities adsorbed from the exhaust gas by the catalyst during use are washed away, so as to improve the catalytic efficiency of the catalyst, and the powder after dust removal is dried, and the powder is dissolved in an acidic environment provided by a mixed solution of sodium sulfite and sulfuric acid to obtain a soluble vanadate, so as to achieve the purpose of chemically purifying the vanadium element and separating it from the original solid waste, and obtaining tetravalent vanadium through a reduction reaction for subsequent treatment, and the vanadium-zinc mixed precipitate is pulped, the precipitate is extracted, and the tetravalent vanadium precipitate is oxidized and calcined to obtain a solid vanadium pentoxide, so as to facilitate the separation of vanadium and the removal of excess waste liquid and the oxidation of tetravalent vanadium. Pure vanadium pentoxide is obtained again, and then the vanadium pentoxide is degraded by microorganisms of the genus Thiobacillus, and the carbon deposits and sulfur in the vanadium pentoxide are degraded into harmless substances, thereby restoring the activity of the catalyst. Then, the catalyst is immersed in hot air through the hot air regeneration method, and the pollutants on the surface of the catalyst are removed by high-temperature oxidation, and the surface active components of the catalyst are restored, so that the activity of the catalyst is restored. Finally, the solid vanadium pentoxide is soaked in aluminum sulfate solution and then dried. The compression resistance and wear resistance of aluminum sulfate after drying are used to harden the surface of the regenerated SCR denitration catalyst, increase the compressive strength of the windward side, and strengthen the resistance, thereby extending the service life of the SCR denitration catalyst in the reactor.

[0030] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

[0031] It will be apparent to those skilled in the art that the invention is not limited to the details of the exemplary embodiments described above and that the invention can be implemented in other specific forms without departing from the spirit or essential features of the invention. Therefore, the embodiments should be considered exemplary and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description, and it is intended that all variations falling within the meaning and scope of the equivalent elements of the claims be included in the invention. Any reference numeral in a claim should not be considered as limiting the claim to which it relates.

[0032] In addition, it should be understood that although the present specification is described according to implementation modes, not every implementation mode contains only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment may also be appropriately combined to form other implementation modes that can be understood by those skilled in the art.

Claims

1. A method for reconstructing and regenerating a ship SCR denitration catalyst, characterized in that: The method comprises the following steps: s100, pre-treating the collected solid waste of SCR deoxidized catalyst of ships, s200, chemical cleaning of the solid waste, s300, intermediate heat treatment of the solid waste, s400, active implantation of the solid waste, s500, final heat treatment, and s600, sorting and windward side reinforcement.

2. The method for reconstructing and regenerating a ship SCR denitration catalyst according to claim 1, characterized in that: In the step s100, the pretreatment of solid waste is to grind and remove dust from the collected waste catalysts by using an MJW-W grading impact mill. The material is crushed by the strong impact of the high-speed rotating crushing disk and the action of centrifugal force. The crushed material moves to the grading area with the air flow, and the coarse and fine materials are separated by the adjustable grading wheel. The fine powder product is collected, and the coarse material is returned for grinding again. The collected suction powder is washed with water for dust removal, and the dust-removed powder is dried.

3. The method for reconstructing and regenerating a ship SCR denitration catalyst according to claim 1, characterized in that: The chemical cleaning of the solid waste in step s200 adopts an acidic ammonium salt vanadium precipitation method. First, the powder collected in step s100 is dissolved in an acidic environment provided by a mixed solution of sodium sulfite and sulfuric acid to obtain a soluble vanadate. The vanadate is reduced and heated to 40 to 60 degrees. Zinc powder is added. Carbon dioxide is introduced into the vanadate solution under stirring to adjust the pH and perform a reduction reaction. After the reduction reaction, solid-liquid separation is performed to obtain a vanadium-zinc mixed precipitate and a filtrate. The filtrate is directly recycled for leaching vanadium-containing clinker. The amount of zinc powder added is 0.9 to 0.96 times the theoretical amount for reducing 5-valent V to 4-valent V.

4. A method for reconstructing and regenerating a ship SCR denitration catalyst according to claim 3, characterized in that: In the step s200, the obtained vanadium-zinc mixed precipitate is slurried, sulfuric acid is added to adjust the pH value of the slurry, and solid-liquid separation is performed after sufficient stirring and dissolution to obtain a tetravalent vanadium precipitate and a zinc sulfate solution, the precipitate is extracted and the tetravalent vanadium precipitate is subjected to the intermediate heat treatment in step s300, and the precipitate is subjected to oxidative calcination treatment to obtain a solid vanadium pentoxide substance.

5. The method for reconstructing and regenerating a ship SCR denitration catalyst according to claim 1, characterized in that: In step s400, the active implantation of solid waste is to degrade the vanadium pentoxide obtained in step s300 by microorganisms, degrading carbon deposits and sulfur and other substances in the vanadium pentoxide into harmless substances, thereby restoring the activity of the catalyst. The microorganisms can be selected from the genus Thiobacillus, which degrades hydrogen sulfide at a temperature of 28 to 30°C. Through this process, the genus Thiobacillus itself will be reproduced, so it can be used continuously.

6. The method for reconstructing and regenerating a ship SCR denitration catalyst according to claim 1, characterized in that: In step 500, the final heat treatment is to immerse the catalyst in hot air through hot air regeneration, remove pollutants on the catalyst surface through high-temperature oxidation, and restore the surface active components of the catalyst. The advantages of this method are simple operation and low cost.

7. A method for reconstructing and regenerating a ship SCR denitration catalyst according to claim 6, characterized in that: In step 600, the finishing and windward surface reinforcement include preparing a reinforcement solution, which is prepared by mixing aluminum sulfate powder and deionized water in a ratio of 1:4, heating to 80 degrees, stirring at a constant temperature for 2 hours, naturally cooling to room temperature, and then vertically inserting solid vanadium pentoxide into the solution, and finally placing it in a hot air furnace for drying at 100 degrees for 30 minutes.

Images