Method and device for purifying VOCs (Volatile Organic Compounds) through gas-phase photolysis and liquid-phase photocatalytic oxidation

Abstract

The invention discloses a method and a device for purifying VOCs (Volatile Organic Compounds) through gas-phase photolysis and liquid-phase photocatalytic oxidation. The method comprises the following steps: S1, gas-phase photolysis: irradiating the VOCs under an UV (Ultraviolet)-light condition, enabling the photolysis time to be less than 1s, generating ozone by reaction, and forming a mixed gas by the ozone and a residual gas after photolysis; S2, liquid-phase photocatalysis: carrying out reverse gas-liquid contact on the mixed gas obtained in S1 and catalyst slurry, enabling the mixed gas to fully react with the catalyst slurry, and enabling the mixed gas to be converted into CO2 and H2O. According to the method for purifying the VOCs through the gas-phase photolysis and the liquid-phase photocatalytic oxidation, disclosed by the invention, the gas-phase photolysis and the liquid-phase photocatalytic oxidation are effectively combined, and the two steps influence each other, work together and cannot be divided; the problems of catalyst deactivation and low liquid-phase absorption efficiency of the VOCs due to deposition of an intermediate product on a gas-solid catalytic surface are fundamentally solved; through a synergistic effect of multiple processes of high-energy ultraviolet photolysis, the liquid-phase photocatalysis, ozone catalytic oxidation and the like, the generation and the deposition of the intermediate product are reduced, and efficient and stable degradation of organic waste gas is realized.

Description

technical field

[0001] The invention belongs to the field of gas pollutant treatment, and in particular relates to a method and a device for purifying volatile organic compounds by gas-phase photolysis-liquid-phase photocatalytic oxidation. Background technique

[0002] With the rapid advancement of urbanization and industrialization in my country, the emission of organic waste gas is increasing, air pollution is becoming more and more serious, and volatile organic compounds (VOCs) in ambient air have increased significantly. Volatile organic compounds (VOCs) are key air pollutants PM2.5 and O in my country. 3 The important precursors formed are easy to couple with other atmospheric pollutants, and the new pollutants formed are difficult to decompose naturally, and the damage is more lasting. In addition, it can also participate in photochemical reactions, leading to photochemical smog pollution. Organic waste gas often has a foul smell, which not only stimulates the human...

Examples

Embodiment 1

[0042] A method for purifying volatile organic compounds by gas-phase photolysis-liquid-phase photocatalytic oxidation, comprising the steps of:

[0043] S1. The experiment uses a UV lamp to decompose benzene, a volatile organic compound with a concentration of 15-50ppm, at a flow rate of 1L / min and a humidity of 50%, under the irradiation conditions of a UV lamp with a wavelength of 185nm for 0.5s, and the reaction produces ozone. The residual gas after photolysis forms a mixed gas;

[0044] S2. Pass the gas-phase photolyzed mixed gas into the liquid-phase photocatalytic spray tower, and the catalyst slurry TiO 2 (P25) From top to bottom, the mixed gas is from bottom to top, and the two are in reverse gas-liquid contact. Under the irradiation of a vacuum ultraviolet lamp, through the process of liquid phase absorption, ultraviolet photocatalytic oxidation, and ozone catalytic oxidation, VOCs are finally converted into CO 2 and H 2 O, discharged through the gas outlet, benze...

Embodiment 2

[0047] A method for purifying volatile organic compounds by gas-phase photolysis-liquid-phase photocatalytic oxidation, comprising the steps of:

[0048] S1. The experiment uses a UV lamp to decompose the volatile organic compound benzene with a concentration of 15~50ppm at a flow rate of 1L / min and a humidity of 50%. Under the conditions of a vacuum UV lamp with a wavelength of 254nm, the gas phase photolysis is carried out for 0.8s, and the reaction generates ozone. , to form a mixed gas with the residual gas after photolysis;

[0049] S2. Pass the gas-phase photolysis mixed gas into the liquid-phase photocatalytic spray tower, and the catalyst slurry is TiO modified by Mn 2 (P25) (Mn loadings are 0.1%, 1%, 3% and 5% respectively), the catalyst slurry is from top to bottom, the mixed gas is from bottom to top, the two are in reverse gas-liquid contact, under the irradiation of vacuum ultraviolet lamp After liquid phase absorption, ultraviolet photocatalytic oxidation, and o...

Embodiment 3

[0052] The present embodiment provides a gas phase photolysis-liquid phase photocatalysis device based on the above method, such as Figure 1~3 As shown, it includes a gas phase photolysis chamber 3, a liquid phase photocatalytic spray tower 1 and a liquid recovery regeneration box 15, and the liquid phase photocatalytic spray tower 1 is sequentially provided with an exhaust gas intake device 13, a filter Ball layer 11, absorption liquid spray device 9, mist eliminator 12 and gas discharge port 14, the lower part of the liquid phase photocatalytic spray tower 1 is connected with the upper part of the liquid recovery regeneration box 15, and the liquid recovery regeneration box 15 It is connected with the absorption liquid spraying device 9 through the liquid delivery pipeline 5 and the circulation pump 2 . The absorption liquid spraying device 9 includes several solution branch pipes, and the solution branch pipes are all communicated with the liquid delivery pipeline 5, and t...

technical field

[0001] The invention belongs to the field of gas pollutant treatment, and in particular relates to a method and a device for purifying volatile organic compounds by gas-phase photolysis-liquid-phase photocatalytic oxidation. Background technique

[0002] With the rapid advancement of urbanization and industrialization in my country, the emission of organic waste gas is increasing, air pollution is becoming more and more serious, and volatile organic compounds (VOCs) in ambient air have increased significantly. Volatile organic compounds (VOCs) are key air pollutants PM2.5 and O in my country. 3 The important precursors formed are easy to couple with other atmospheric pollutants, and the new pollutants formed are difficult to decompose naturally, and the damage is more lasting. In addition, it can also participate in photochemical reactions, leading to photochemical smog pollution. Organic waste gas often has a foul smell, which not only stimulates the human...

Examples

Embodiment 1

[0042] A method for purifying volatile organic compounds by gas-phase photolysis-liquid-phase photocatalytic oxidation, comprising the steps of:

[0043] S1. The experiment uses a UV lamp to decompose benzene, a volatile organic compound with a concentration of 15-50ppm, at a flow rate of 1L / min and a humidity of 50%, under the irradiation conditions of a UV lamp with a wavelength of 185nm for 0.5s, and the reaction produces ozone. The residual gas after photolysis forms a mixed gas;

[0044] S2. Pass the gas-phase photolyzed mixed gas into the liquid-phase photocatalytic spray tower, and the catalyst slurry TiO 2 (P25) From top to bottom, the mixed gas is from bottom to top, and the two are in reverse gas-liquid contact. Under the irradiation of a vacuum ultraviolet lamp, through the process of liquid phase absorption, ultraviolet photocatalytic oxidation, and ozone catalytic oxidation, VOCs are finally converted into CO 2 and H 2 O, discharged through the gas outlet, benze...

Embodiment 2

[0047] A method for purifying volatile organic compounds by gas-phase photolysis-liquid-phase photocatalytic oxidation, comprising the steps of:

[0048] S1. The experiment uses a UV lamp to decompose the volatile organic compound benzene with a concentration of 15~50ppm at a flow rate of 1L / min and a humidity of 50%. Under the conditions of a vacuum UV lamp with a wavelength of 254nm, the gas phase photolysis is carried out for 0.8s, and the reaction generates ozone. , to form a mixed gas with the residual gas after photolysis;

[0049] S2. Pass the gas-phase photolysis mixed gas into the liquid-phase photocatalytic spray tower, and the catalyst slurry is TiO modified by Mn 2 (P25) (Mn loadings are 0.1%, 1%, 3% and 5% respectively), the catalyst slurry is from top to bottom, the mixed gas is from bottom to top, the two are in reverse gas-liquid contact, under the irradiation of vacuum ultraviolet lamp After liquid phase absorption, ultraviolet photocatalytic oxidation, and o...

Embodiment 3

[0052] The present embodiment provides a gas phase photolysis-liquid phase photocatalysis device based on the above method, such as Figure 1~3 As shown, it includes a gas phase photolysis chamber 3, a liquid phase photocatalytic spray tower 1 and a liquid recovery regeneration box 15, and the liquid phase photocatalytic spray tower 1 is sequentially provided with an exhaust gas intake device 13, a filter Ball layer 11, absorption liquid spray device 9, mist eliminator 12 and gas discharge port 14, the lower part of the liquid phase photocatalytic spray tower 1 is connected with the upper part of the liquid recovery regeneration box 15, and the liquid recovery regeneration box 15 It is connected with the absorption liquid spraying device 9 through the liquid delivery pipeline 5 and the circulation pump 2 . The absorption liquid spraying device 9 includes several solution branch pipes, and the solution branch pipes are all communicated with the liquid delivery pipeline 5, and t...

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