Regeneration method of arsenic poisoning denitration catalyst
The arsenic-poisoned denitrification catalyst was regenerated by means of compressed air cleaning, alkaline cleaning, acid cleaning, and soaking and calcination in regeneration solution. This solved the problem of catalyst deactivation and achieved efficient denitrification efficiency recovery and resource regeneration.
Patent Information
- Application Number
- CN202511308586.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-09-15
- Publication Date
- 2025-12-12
AI Technical Summary
In existing technologies, denitrification catalysts in coal-fired power plants become deactivated due to arsenic poisoning, resulting in a reduced chemical lifespan of the catalysts, inability to regenerate effectively, and causing resource waste and high replacement costs.
The arsenic-poisoned denitrification catalyst is regenerated by a series of steps including compressed air cleaning, alkaline cleaning, acid cleaning, soaking in regenerable solution, and drying and calcination. Combined with ultrasonic-assisted treatment, deep purification is carried out using alkaline solution, dilute sulfuric acid, and regenerable solutions such as oxalic acid, ammonium metavanadate, and ammonium molybdate.
It effectively removes arsenic, restores the denitrification activity of the catalyst, and increases the denitrification efficiency to 80-88%, meeting the requirements of new catalysts. It also has the ability to resist arsenic poisoning, reducing resource waste and costs.
Abstract
Description
TECHNICAL FIELD
[0001] The application belongs to the technical field of coal-fired power plant catalysts, and particularly relates to a regeneration method of an arsenic-poisoned denitration catalyst. BACKGROUND
[0002] The selective catalytic reduction (SCR) denitration technology is widely applied to industrial flue gas treatment such as coal-fired power plants, steel, and cement, and obvious effects have been achieved in nitrogen oxide (NOx) emission reduction. However, the denitration catalyst will be deactivated due to physical blockage and chemical poisoning in long-term operation. In order to continuously meet the national emission requirements for denitration, the deactivated catalyst must be replaced. The replacement of a brand-new catalyst is costly, the waste denitration catalyst is listed as hazardous waste and needs special disposal, and therefore, the regeneration of the deactivated catalyst is a cost-effective alternative solution.
[0003] Arsenic (As) poisoning is one of the common reasons for the deactivation of the denitration catalyst. The arsenic poisoning is mainly caused by coal-fired flue gas. The arsenic content in coal in China varies obviously, and the As content is from 0.5-80 ppm. The gaseous As203 content in high-temperature flue gas depends on the arsenic content in coal and the boiler combustion condition. The arsenic poisoning will significantly reduce the chemical life of the denitration catalyst. Therefore, it is necessary to develop a regeneration method for the arsenic-poisoned denitration catalyst. SUMMARY
[0004] The purpose of the present application is to provide a regeneration method of an arsenic-poisoned denitration catalyst to solve the problem that arsenic poisoning significantly reduces the chemical life of the denitration catalyst.
[0005] To achieve the above purpose, the technical scheme adopted by the present application is as follows: A regeneration method of an arsenic-poisoned denitration catalyst, comprising the following steps: (1) Dust cleaning: the deactivated denitration catalyst poisoned by arsenic is subjected to physical dust cleaning treatment by compressed air, and the blowing time is 10-30 minutes; (2) Alkaline cleaning: the deactivated denitration catalyst after the dust cleaning in step (1) is soaked in an alkali solution with a mass fraction of 1-10% at 50-95 ℃, and ultrasonic-assisted soaking is performed for 60-120 minutes; (3) Acidic cleaning: the catalyst obtained in step (2) is taken out and subjected to ultrasonic-assisted soaking cleaning in a dilute sulfuric acid solution with a concentration of 0.1-0.5 mol / L for 10-30 minutes, the residual alkali solution on the surface of the catalyst is neutralized, and then the cleaned catalyst is rinsed with flowing deionized water for 10-30 minutes. The rinsed catalyst is dried at 100-200 ℃ for 1-3 hours; (4) Soaking in regeneration liquid: the dried catalyst is soaked in a regeneration liquid with a mass fraction of 0.1-2% for 10-30 minutes; (5) drying and calcining: the catalyst soaked by the regeneration solution is dried by hot air at 100-200℃ for 1-3 hours, and then calcined in air at 350-450℃ for 2-5 hours to obtain the regenerated denitration catalyst.
[0006] In a further preferred mode, the deactivated denitration catalyst in step (1) is any one of a corrugated catalyst, a plate catalyst or a honeycomb catalyst.
[0007] In a further preferred mode, the alkali solution in step (2) is one or any combination of sodium hydroxide, potassium hydroxide and quaternary ammonium base.
[0008] In a further preferred mode, the regeneration solution in step (4) is an aqueous solution containing 0.1-1wt% of a weak acid, 0.1-2wt% of ammonium metavanadate and 0.1-2wt% of ammonium molybdate.
[0009] In a further preferred mode, the weak acid is one or any combination of oxalic acid, acetic acid and citric acid.
[0010] The method for regenerating the arsenic-poisoned denitration catalyst has the following advantages: (1) The method can effectively remove arsenic components while maintaining the compressive strength, abrasion strength and active components of the denitration catalyst; and the cleaning efficiency is greatly improved by combining with ultrasonic-assisted cleaning; (2) The weak acid in the regeneration solution can further remove residual trace arsenic to achieve the purpose of deep purification; at the same time, the regeneration solution can supplement the active components of the catalyst to improve its denitration activity; and the addition of ammonium molybdate enables the regenerated catalyst to have a certain resistance to arsenic poisoning.
[0011] (3) The denitration activity of the denitration catalyst regenerated by the method is detected, and it is found that the denitration efficiency can reach 80-88%. DETAILED DESCRIPTION
[0012] The application will be further described in detail below in combination with specific embodiments.
[0013] A power plant burns coal with a high arsenic content, and after 2 years of actual operation, the SCR denitration catalyst is seriously poisoned by arsenic. Three arsenic-poisoned denitration catalysts with a size of 150mm*150mm*880mm are randomly taken, and the denitration efficiency of the deactivated denitration catalyst before regeneration is 25%. EMBODIMENT
[0014] The arsenic-poisoned denitration catalyst is regenerated by the following steps in this embodiment.
[0015] (1) Dust cleaning: the arsenic-poisoned denitration catalyst is first subjected to physical dust cleaning treatment by compressed air, and the blowing time is 10 minutes; (2) Alkaline cleaning: the deactivated catalyst after dust removal in step (1) is soaked in a 50℃ 1% sodium hydroxide aqueous solution, and ultrasonic-assisted soaking is performed for 60 minutes; (3) Acid cleaning: the catalyst obtained in step (2) is taken out, ultrasonic-assisted soaking cleaning is performed in a 0.1 mol / L dilute sulfuric acid solution for 20 minutes, the residual lye on the surface of the catalyst is neutralized, then flowing deionized water is used for rinsing for 30 minutes, and the washed catalyst is dried at 200℃ for 3 hours; (4) Regeneration liquid soaking: the dried catalyst is soaked in a regeneration liquid for 15 minutes, the regeneration liquid is a 2% oxalic acid, ammonium metavanadate and ammonium molybdate aqueous solution.
[0016] (5) Drying and calcination: the catalyst after regeneration liquid soaking is dried by using 200℃ hot air for 3 hours, and then calcination is performed at 450℃ in air for 3 hours to obtain a regenerated denitration catalyst.
[0017] The arsenic removal method of the present application can well remove arsenic elements in the arsenic-poisoned denitration catalyst, so that the content of arsenic is reduced to within 50ppm, and the arsenic content can meet the requirements of new SCR denitration catalyst. By measuring the arsenic content of the denitration catalyst before and after regeneration, the removal rate of arsenic is calculated, and the denitration activity of the regenerated denitration catalyst is tested, and it is found that the denitration efficiency is restored from 25% to 80%.
[0018] The denitration efficiency is calculated according to the formula: denitration efficiency=(inlet NOx concentration-outlet NOx concentration)÷ inlet NOx concentration x 100%.
[0019] The measurement results show that the arsenic removal rate in this embodiment is 78%, and the denitration efficiency is 80%. Embodiment
[0020] The arsenic-poisoned denitration catalyst is regenerated by the following steps in this embodiment.
[0021] (1) Dust removal: the arsenic-poisoned denitration catalyst is first subjected to physical dust removal treatment by using compressed air, and the blowing time is 15 minutes; (2) Alkaline cleaning: the deactivated catalyst after dust removal in step (1) is soaked in a 65℃ 4% sodium hydroxide aqueous solution, and ultrasonic-assisted soaking is performed for 90 minutes; (3) Acid cleaning: the catalyst obtained in step (2) is taken out, ultrasonic-assisted soaking cleaning is performed in a 0.2 mol / L dilute sulfuric acid solution for 20 minutes, the residual lye on the surface of the catalyst is neutralized, then flowing deionized water is used for rinsing for 30 minutes, and the washed catalyst is dried at 200℃ for 3 hours; (4) Regeneration liquid soaking: the dried catalyst is soaked in a regeneration liquid for 15 minutes, and the regeneration liquid is a 2% mass fraction oxalic acid, ammonium metavanadate, and ammonium molybdate aqueous solution.
[0022] (5) Drying and calcination: the catalyst soaked in the regeneration liquid is dried by using 200℃ hot air for 3 hours, and then is calcined in air at 450℃ for 3 hours to obtain the regenerated denitration catalyst.
[0023] The arsenic removal method of the present application can well remove arsenic elements in the arsenic-poisoned denitration catalyst, so that the content of arsenic is reduced to within 50ppm, and the arsenic content can meet the requirements of new SCR denitration catalyst. By measuring the arsenic content of the denitration catalyst before and after regeneration, the removal rate of arsenic is calculated, and the denitration activity of the regenerated denitration catalyst is tested, and it is found that the denitration efficiency is restored from 25% to 88%.
[0024] Denitration efficiency calculation, calculation formula: denitration efficiency = (inlet NOx concentration-outlet NOx concentration) ÷ inlet NOx concentration x 100%.
[0025] The results show that the arsenic removal rate is 85% and the denitration efficiency is 88% in this embodiment. Embodiment
[0026] The arsenic-poisoned denitration catalyst is regenerated by the following steps in this embodiment.
[0027] (1) Dust cleaning: the arsenic-poisoned denitration catalyst is first subjected to physical dust cleaning treatment by using compressed air, and the blowing time is 30 minutes; (2) Alkaline cleaning: the deactivated catalyst after dust cleaning in step (1) is soaked in a 65℃ 4% mass fraction potassium hydroxide aqueous solution, and ultrasonic-assisted soaking is performed for 120 minutes; (3) Acid cleaning: the catalyst obtained in step (2) is taken out and ultrasonic-assisted soaking cleaning is performed in a 0.3mol / L dilute sulfuric acid solution for 20 minutes, so as to neutralize the residual alkali solution on the surface of the catalyst, and then the catalyst is rinsed with flowing deionized water for 30 minutes, and the washed catalyst is dried at 200℃ for 3 hours; (4) Regeneration liquid soaking: the dried catalyst is soaked in a regeneration liquid for 15 minutes, and the regeneration liquid is a 2% mass fraction oxalic acid, ammonium metavanadate, and ammonium molybdate aqueous solution.
[0028] (5) Drying and calcination: the catalyst soaked in the regeneration liquid is dried by using 200℃ hot air for 3 hours, and then is calcined in air at 450℃ for 3 hours to obtain the regenerated denitration catalyst.
[0029] The arsenic removal method of the present application can well remove arsenic elements in the arsenic-poisoned denitration catalyst, so that the content of arsenic is reduced to within 50 ppm, and the arsenic content can meet the requirements of new SCR denitration catalyst. By measuring the arsenic content of the denitration catalyst before and after regeneration, the removal rate of arsenic is calculated, and the denitration activity of the regenerated denitration catalyst is tested. It is found that the denitration efficiency is restored from 25% to 83%.
[0030] The denitration efficiency is calculated according to the formula: denitration efficiency = (inlet NOx concentration - outlet NOx concentration) ÷ inlet NOx concentration x 100%.
[0031] The test results show that the removal rate of arsenic in this embodiment is 80%, and the denitration efficiency is 83%.
Claims
1. A method for regenerating an arsenic-poisoned deNOx catalyst, characterized by, Includes the following steps: (1) Cleaning: Physical cleaning treatment of the deactivated denitrification catalyst poisoned by arsenic is carried out with compressed air for 10 to 30 minutes; (2) Alkaline cleaning: The deactivated denitrification catalyst after cleaning in step (1) is immersed in an alkaline solution with a mass fraction of 1-10% at 50-95℃ and ultrasonically assisted for 60-120 minutes; (3) Acid cleaning: Take out the catalyst obtained in step (2) and clean it in a 0.1-0.5 mol / L dilute sulfuric acid solution with ultrasonic assistance for 10-30 min to neutralize the residual alkali on the surface of the catalyst. Then rinse it with flowing deionized water for 10-30 min. Dry the cleaned catalyst at 100-200℃ for 1-3 hours. (4) Regeneration solution soaking: Soak the dried catalyst in a regeneration solution with a mass fraction of 0.1-2% for 10-30 minutes; (5) Drying and calcining: The catalyst soaked in the regenerated liquid is dried with hot air at 100-200°C for 1-3 hours, and then calcined in air at 350-450°C for 2-5 hours to obtain the regenerated denitrification catalyst.
2. The method for regenerating an arsenic-poisoned deNOx catalyst according to claim 1, characterized by, The deactivated denitration catalyst in step (1) is any one of corrugated catalyst, plate catalyst or honeycomb catalyst.
3. The method of claim 1, wherein the method is characterized by, The alkaline solution in step (2) is one or any combination of sodium hydroxide, potassium hydroxide, and quaternary ammonium base.
4. The regeneration method for the arsenic poisoning denitrification catalyst according to claim 1, characterized in that, The regenerated solution in step (4) is an aqueous solution of a weak acid with a content of 0.1-1 wt%, ammonium metavanadate with a content of 0.1-2 wt%, and ammonium molybdate with a content of 0.1-2 wt%.
5. The regeneration method for the arsenic poisoning denitrification catalyst according to claim 4, characterized in that, The weak acid mentioned is one or any combination of oxalic acid, acetic acid, or citric acid.