Catalyst for removing low-concentration formaldehyde in gases and application thereof

A technology for removing gases and catalysts, applied in molecular sieve catalysts, physical/chemical process catalysts, chemical instruments and methods, etc., can solve problems such as failure, and achieve the effect of low energy consumption

Inactive Publication Date: 2011-04-06
DALIAN UNIV OF TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, the main disadvantage of the adsorption method is that the adsorbent will quickly fail due to the limitation of the adsorption capacity and the influence of the competitive a

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0011] Example 1: HZSM-5 (referred to as HZ, the same below) powder was calcined at 600°C for 3 hours, and then tableted, crushed and sieved to obtain a particle size of 20-40 mesh.

[0012] A reactor capable of dielectric barrier discharge: a stainless steel high-voltage electrode with a diameter of 3mm is located at the axis of a quartz glass tube with an inner diameter of 8mm and a wall thickness of 1mm, and a stainless steel mesh with a height of 3mm is tightly wound on the outer wall of the quartz glass tube as a grounding electrode. Fill the discharge area between the quartz tube and the stainless steel high voltage electrode with 1.5ml of 20-40 mesh HZ particles. Under normal temperature and pressure, simulated air with a formaldehyde concentration of 24.4ppm and a water content of 50% relative humidity at 25°C passes through the HZ catalyst bed at a flow rate of 300ml / min, and formaldehyde is stored on the HZ catalyst. After 40 minutes, formaldehyde molecules began to ...

Embodiment 2

[0013] Example 2: After calcining the HZ powder at 600° C. for 3 hours, pour it into the mixed solution of silver nitrate and copper nitrate. After the HZ molecular sieve carrier was immersed in the solution for 12 hours, it was dried at 120° C. and calcined at 600° C. for 3 hours. Then press into tablets, crush and sieve to obtain 20-40 mesh AgCu / HZ catalyst particles. The weight percentages of Ag and Cu loadings in the catalyst were 3.6% and 2.1%, respectively.

[0014] 1.5 ml of 20-40 mesh AgCu / HZ catalyst particles were packed in the discharge area of ​​the dielectric barrier discharge reactor described in Example 1. Under normal temperature and pressure, simulated air with a formaldehyde concentration of 26.2ppm and a water content of 50% relative humidity at 25°C passes through the AgCu / HZ catalyst bed at a flow rate of 300ml / min, and formaldehyde is stored on the AgCu / HZ catalyst. After 165 minutes, formaldehyde molecules began to penetrate the AgCu / HZ catalyst bed an...

Embodiment 3

[0015] Example 3: 1.5 ml of the AgCu / HZ catalyst prepared in Example 2 was loaded into the discharge area of ​​the dielectric barrier discharge reactor described in Example 1. Under normal temperature and pressure, simulated air with a formaldehyde concentration of 26.6ppm and a water content of 93% relative humidity at 25°C passes through the AgCu / HZ catalyst bed at a flow rate of 300ml / min, and formaldehyde is stored on the AgCu / HZ catalyst. After 168 min, formaldehyde molecules began to penetrate the AgCu / HZ catalyst bed and the storage reached saturation. The formaldehyde breakthrough storage capacity under this condition was 1.8 mg. Then turn over to the regeneration stage: the flow of oxygen that is 60ml / min flows through the AgCu / HZ catalyzer that stores formaldehyde, and the AC high voltage that applies frequency is 2kHz to make this reactor take place dielectric barrier discharge (discharge power is 2.3W), to AgCu / HZ catalyst for regeneration. Formaldehyde stored on...

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PUM

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Abstract

The invention belongs to the technical field of gas purification treatment, relating to a catalyst for removing low-concentration formaldehyde in gases and the application thereof. The catalyst is characterized by using at least two of Ag, Co, Fe and Cu as main active components which are loaded on an HZSM-5 type molecular sieve carrier and are 1-20 percent by weight of the catalyst. The catalyst is filled in a reactor and applied to two alternately operating stages, i.e. a storage stage and a regeneration stage, wherein the reactor can be inflated with ozone, can be used for heating at a controlled temperature and can carry out DBD (Dielectric Barrier Discharges). At the storage stage, low-concentration formaldehyde in the gases is firstly stored on the catalyst; and at the regeneration stage, ozone or oxygen-contained gas is introduced for heating or carrying out the DBD so that the formaldehyde stored on the catalyst is fully oxidized into carbon dioxide and water, wherein the oxygen content in the introduced oxygen-contained gas at the regeneration stage is 20-100 percent, and air can be directly used as the oxygen-contained gas at the regeneration stage. In the invention, the provided catalyst with the function of selective storing and catalytic oxidation on the formaldehyde has the advantages of low energy consumption and no secondary pollution, is extremely suitable for removing low-concentration formaldehyde in gases and is particularly suitable for removing formaldehyde pollutants in indoor air.

Description

technical field [0001] The invention belongs to the technical field of gas purification treatment, and relates to a catalyst for removing low-concentration formaldehyde in gas and its application. Background technique [0002] Formaldehyde is a typical volatile organic pollutant (VOCs), especially in indoor air. Because formaldehyde has strong carcinogenic and cancer-promoting effects, it has been listed as carcinogenic and teratogenic shape substances by the World Health Organization, is a recognized source of allergies, and is also one of potential strong mutagens. Therefore, countries around the world have made very strict regulations on the concentration of formaldehyde in indoor air. The allowable value of formaldehyde concentration in indoor air stipulated by my country is 0.08mg / m 3 . [0003] At present, the technologies used in air purification to remove formaldehyde mainly include catalytic oxidation, photocatalysis, adsorption and so on. Although the photocatal...

Claims

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Application Information

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IPC IPC(8): B01J29/46B01D53/86B01D53/72
Inventor 朱爱民李小松石川赵德志
Owner DALIAN UNIV OF TECH
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