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Method for degrading dioxin in fly ash through wet catalytic oxidation

A technology of wet catalytic oxidation and fly ash, which is applied in the direction of protection devices against harmful chemicals, and can solve the problem of low dioxin content

Inactive Publication Date: 2021-07-30
NANJING NORMAL UNIVERSITY +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

Chinese invention application (CN111744501.A) proposes a catalyst with cerium-manganese-copper composite oxide as the catalytic active component, which can simultaneously and efficiently catalyze and remove nitrogen oxides, mercury, dioxins and carbon monoxide in the tail gas, and dioxins The degradation efficiency is above 95%, but the dioxin content in the tail gas it treats is extremely low, at the ng level, it is only suitable for tail gas treatment with low concentration pollutants, and the reaction temperature is above 350°C

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  • Method for degrading dioxin in fly ash through wet catalytic oxidation
  • Method for degrading dioxin in fly ash through wet catalytic oxidation
  • Method for degrading dioxin in fly ash through wet catalytic oxidation

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Embodiment 1 2

[0030] The preparation of the cerium copper catalyst supported by embodiment 1 titania

[0031] The titania-supported cerium-copper catalyst was prepared by conventional co-precipitation method. Ce(SO with a mass ratio of 1:0.25:14 4 ) 2 4H 2 O, CuSO 4 ·5H 2 O and Ti(SO 4 ) 2 2H 2 After O was dissolved in a certain amount of ion-exchanged water, ammonia solution was slowly added (at a rate of less than 0.3 mL / min), while vigorously stirring to achieve the effect of co-precipitation until the pH value of the solution reached 9.5. After washing and filtering to remove sulfate ions, the precipitate was first dried in a water bath at 80°C for 4 hours, then dried in a vacuum oven at 50°C for 12 hours, and finally dried at 110°C for 4 hours. The final product obtained is calcined at 500° C. for 5 hours under air condition to obtain the desired catalyst.

Embodiment 2

[0033] The fly ash incinerated from grate furnace domestic waste was washed three times with countercurrent water at a liquid-solid ratio of 4:1g / mL, and fully dried. After drying, the mass content of chlorine in the fly ash was about 1.8%, and the content of dioxin It is 1.87μgTEQ / kg. Using an electrically heated high-temperature and high-pressure reactor (CJ type reactor) equipped with mechanical stirring produced by Weihai Xinyuan Chemical Machinery Co., Ltd., accurately weigh 80g of fly ash and add 320mL of pure water, then add 30% mass fraction of hydroxide The sodium solution adjusted the pH to 10, and then added 0.5 g of titania-supported cerium-copper catalyst ((Ce+Cu) / TiO 2 , Ce: Cu: Ti molar ratio is 1:0.4:20). After adding materials, tighten the screws and valves of the reactor and feed 1MPa pure oxygen. Set the reaction temperature to 260, 280, and 300°C respectively, the reaction time to 120min, and the stirring rate to 120r / min. Cooling water is fed to the mixer...

Embodiment 3

[0038]The fly ash incinerated from grate furnace domestic waste was washed three times with countercurrent water at a liquid-solid ratio of 4:1g / mL, and fully dried. After drying, the mass content of chlorine in the fly ash was about 1.8%, and the content of dioxin It is 1.87μgTEQ / kg. Using an electrically heated high-temperature and high-pressure reactor (CJ type reactor) equipped with mechanical stirring produced by Weihai Xinyuan Chemical Machinery Co., Ltd., accurately weigh 80g of fly ash and add 320mL of pure water, then add 30% mass fraction of hydroxide The sodium solution adjusted the pH to 10, and then added 0.5 g of titania-supported cerium-copper catalyst ((Ce+Cu) / TiO 2 , Ce: Cu: Ti molar ratio is 1:0.4:20). After adding materials, tighten the screws and valves of the reactor and feed 1MPa pure oxygen. Set the reaction temperature to 260°C, the reaction time to 60, 90, 120, and 180 minutes respectively, and the stirring rate to 120r / min. water. The degradation e...

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Abstract

The invention discloses a method for degrading dioxin in fly ash by wet catalytic oxidation, which comprises the step of performing catalytic reaction on a mixture of fly ash and water under an alkaline condition through a titanium dioxide loaded cerium-copper catalyst to degrade the dioxin. The method provided by the invention not only can degrade the fly ash containing dioxin with the toxic equivalent of 0.5-3 [mu] gTEQ / kg to 50 ng-TEQ / kg or below to meet the requirements of household garbage incineration fly ash pollution control technical specifications, but also can reduce the reaction temperature, shorten the reaction time and further reduce the energy consumption while improving the reaction efficiency.

Description

technical field [0001] The invention relates to the technical field of domestic waste incineration fly ash treatment, in particular to a wet catalytic oxidation method for degrading dioxins in fly ash. Background technique [0002] With the rapid development of my country's urbanization and the improvement of people's living standards, the generation of urban domestic waste has also increased rapidly. In 2018, the national urban domestic waste removal volume reached 228.018 million tons. Domestic waste incineration has gradually become the mainstream method of domestic waste disposal in my country due to its advantages of obvious reduction, less land occupation and energy conversion. The generated domestic waste incineration fly ash (hereinafter referred to as fly ash) is a powdery substance collected by the domestic waste incineration flue gas purification system and belongs to hazardous waste. In recent years, with the rapid growth of urban domestic waste production, the ...

Claims

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Application Information

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IPC IPC(8): A62D3/38
CPCA62D3/38
Inventor 边博张桐周乔马晨皓田甘沛张利民
Owner NANJING NORMAL UNIVERSITY
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