Removal of formaldehyde from indoor air

In life, in addition to the harmful effects of formaldehyde and other harmful substances on the human body, there are some health hazards that you don’t know about. Did you know that the so-called "benzene" is actually a series of substances, including "benzene", "toluene" and "xylene". Removal of formaldehyde in indoor air. According to the introduction of formaldehyde inside the formaldehyde, formaldehyde not only causes great harm to the human body, but the presence of benzene compounds cannot be ignored. It is recognized by the medical community that benzene can cause leukemia and aplastic anemia.

1. Methanol oxidation method: At 600~700℃, methanol, air and water are directly oxidized through a silver catalyst or a catalyst such as copper or vanadium pentoxide to generate formaldehyde, which is then absorbed by water to obtain a formaldehyde solution. The overall reaction is an exothermic reaction, but 50~60% of the formaldehyde is generated through oxidation reaction, while the rest is generated through hydrogen reaction. By-products are carbon monoxide and carbon dioxide, methyl formate and formic acid. The methanol conversion rate is 80%, and the yield based on methanol is 85%~90%. This method has mature technology and high yield and is widely adopted by manufacturers at home and abroad.

2. Natural gas oxidation method: At 600-680℃, a mixture of natural gas and air is directly oxidized through an oxide catalyst such as iron or molybdenum to generate formaldehyde, which is then absorbed with water to obtain a formaldehyde solution:

3. Dimethyl ether oxidation method: dimethyl ether produced as a by-product of methanol synthesis using synthesis gas high-pressure method is used as raw material and oxidized using metal oxides as catalysts.

4. It is produced by dehydrogenating methanol at 300°C using a copper or silver catalyst. When formaldehyde gas absorbs water content of 36% to 40%, it becomes formaldehyde solution. The commercially available formaldehyde solution is distilled to remove impurities and supplemented with methanol to obtain the reagent formaldehyde solution:

5. Methanol dehydrogenation method: Direct dehydrogenation of methanol can produce anhydrous formaldehyde and produce hydrogen as a by-product. This process is an extremely attractive method for preparing formaldehyde. The key to its progress lies in the improvement of process catalyst performance.

6. Mix the vaporized methanol with alkali-washed air and water vapor in a ratio of 1:1.8-2.0:0.8-1.0 (volume ratio), heat to 115-120°C for reaction, and control the reaction temperature to 600-650°C and the pressure to 0.3-0.5 MPa under the action of a silver catalyst. After the reaction, cool the reactants to 80-85°C, absorb them with water, and then distill them to remove the unreacted methanol. Treat the kettle liquid with anion exchange resin, add an appropriate amount of inhibitor to the obtained formaldehyde solution, stir and mix, and obtain the finished product.

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