Optical microwave ultraviolet deodorization equipmentprinciple

The ultraviolet wavelength used in industry is 154nm-254nm, and the shorter the wavelength, the greater the energy. Ultraviolet wavelengths below 254nm can decompose O2 and produce O3, while wavelengths above 254nm cannot decompose O2. Due to the relatively short wavelength range of 154nm-185nm, the spatial range of "killing" is also relatively small. Although 185nm-254nm has a longer wavelength, its lethal space range is relatively large.

The photocatalytic oxidation deodorization equipment uses NBL standard ultraviolet lamps to generate ultraviolet light, of which the wavelength of 154nm-185nm accounts for 14% of the series spectrum. The ultraviolet dose is greater than 45mW/cm2, and the photon energy is greater than 1000kJ/mol. It is currently the highest dose and energy ultraviolet light in industrial UV/O3 lamps. The oxidation bond energy is less than 380kJ/mol (the bond energy and bond length of common chemical bonds are shown in the table below). Ultraviolet photolysis of oxygen produces ozone, and the ozone concentration is configured at 1.8Kg/h. The designed ozone concentration is 200mg/m3. Ozone can oxidize pollutants with strong metallic properties, and the ozone amount can be set according to the concentration of pollutants and subsequent reaction time.

The photocatalytic oxidation mechanism of exhaust gas includes two processes: one is that in the process of generating ion groups, a certain number of harmful gas molecules are affected and decompose into elemental substances or convert into substances. Secondly, it contains a large number of particles and ion groups that interact with large molecular gases (such as benzene, toluene, etc.), opening their molecular chemical bonds and converting them into small molecular substances. Oxygen ions have strong oxidizing properties and can oxidize and decompose substances that are not controlled by the action of negative ions. After reacting with exhaust gas, excess oxygen ions (positive) can quickly combine with oxygen ions (negative) to form neutral oxygen, which can have adverse effects on equipment and the environment. Under the action of ultraviolet radiation, a large amount of reactive oxygen species can accelerate the oxidation rate and efficiency.

Under the action of ultraviolet radiation in the wavelength range of 154nm-184.9nm (1200KJ/mol-600KJ/mol), on the one hand, oxygen in the air is cracked and then combined to produce ozone; On the other hand, breaking the chemical bonds of pollutants to form free atoms or functional groups; The ozone generated simultaneously participates in the reaction process, causing the exhaust gas to be ultimately cracked and oxidized into simple and stable compounds CO2, H2O, N2. The possibility of a series of processes depends on:

(1) Whether pollutant molecules can be cleaved depends on whether their chemical bond energy is lower than the provided UV photon ability?

(2) Does the cracking reaction take 1 second, and does the oxidation reaction take 5-8 seconds;

(3) Is the environment for UV photolysis stable and requires a reaction temperature of<70 ° C and a dust concentration of<200mg/m3,

Relative temperature<200%.

(4) Is the content of certain chemical elements in pollutants too high (such as CL, F);

The bond energy and bond length of common chemical bonds