1、 Chemical absorption oxidation
Use the physical and chemical properties of pollutants, and use water or chemical absorption solution to absorb and remove waste gas. In this method, strong oxidants such as chlorine, ozone, hydrogen peroxide, potassium permanganate and sodium hypochlorite are added to destroy the molecules of odor pollutants, so as to achieve the purpose of deodorization. The common absorbers are vertical packing spray scrubber, vertical swirl plate spray tower and horizontal multistage spray tower.
Chemical absorption oxidation process is a widely used odor control process, with the most remarkable characteristics as follows:
① Operation flexibility, high efficiency of removing hydrogen sulfide, no secondary pollution;
② It can be carried out at normal temperature;
③ Under most conditions, the absorbent is renewable and the operation cost is low;
④ Consume a lot of water, electricity, etc;
⑤ A mist eliminator with good performance shall be provided.
2、UV photolysis method
1. The method of degradation of malodorous pollutants under ultraviolet irradiation by using the photocatalysis characteristics of semiconductor and nano metal oxide. It uses nanoparticles of nano materials (such as TiO2, ZnO, Fe2O3, CDs, WO3, etc.) to generate electron transition and hole action under certain wavelength of light and · Oh in the presence of water vapor to oxidize VOCs into CO2, H2O or other ions (such as Cl -). At present, TiO2 is recognized as the best photocatalyst, which is most commonly used for its low price, non-toxic, high catalytic activity, strong oxidation ability and good stability.
2. Using high energy and high ozone UV light to decompose oxygen molecules in the air to produce free oxygen, i.e. active oxygen. Because of the imbalance of positive and negative electrons carried by free oxygen, it needs to combine with oxygen molecules to produce ozone.
UV photolysis method is a highly effective odor control process, with the most remarkable characteristics as follows:
① Modular design and manufacture, flexible and simple installation;
② High deodorization efficiency;
③ Small land occupation, strong applicability and low operation cost;
④ UV lamp has a certain service life and needs to be replaced regularly.
Plasma is called the fourth form of matter, which is composed of electrons, ions, free radicals and neutral particles. It is a conductive fluid and generally remains electrically neutral. According to the different ion temperature, it can be divided into equilibrium plasma and non-equilibrium plasma. In recent years, the development of non-equilibrium plasma technology has the advantages of simple process, high efficiency, low energy consumption and wide application. Through high voltage discharge, a large number of active particles, such as O, oh, N-groups, are generated by high-energy electrons or excited by high-energy electrons, which destroy the chemical bonds such as C-H, C = C or C-C in VOCs molecules, so that h, Cl, F, etc. in VOCs molecules take place displacement reactions. Due to the strong oxidation ability of O, oh, etc., the decomposition and oxidation of C and h, and the final generation of CO2 and H2O, i.e. VOCs become harmless substances through
Plasma purification is a common odor control process, with the most remarkable characteristics as follows:
① Small land occupation, convenient operation and low operation cost;
② Strong resistance to impact load and no secondary pollution;
③ Large investment and purification effect will also be affected by the concentration;
④ The ion tube needs to be replaced regulaly and the maintenance co is high.