Low-temperature purification VOCs waste gas treatment method adopting low-voltage electrocatalytic oxidation

Abstract

The invention relates to the technical field of industrial waste gas treatment, in particular to a low-temperature purification VOCs waste gas treatment method adopting low-voltage electrocatalytic oxidation, which comprises the following steps: S1, filling a ceramic tube with a solid oxide catalyst; s2, connecting and fixing positive and negative ends of a low-voltage power supply to two ends of the catalyst in the step S1 to form a current loop; s3, VOCs waste gas with a certain concentration is introduced into the ceramic pipe in the step S1 through an induced draft fan; s4, normal-temperature purification of the VOCs can be achieved by adjusting the output voltage and current of the power source. By adjusting the output voltage and current of the low-voltage power supply, VOCs oxidation can be realized at low temperature, high-temperature heating is not needed, energy consumption is greatly reduced, and the method has the remarkable advantages of simplicity and convenience in operation and low energy consumption. Meanwhile, the VOCs can be rapidly degraded, the purpose of high purification efficiency can be achieved at low temperature, and the electrocatalytic oxidation technology has good application prospects and economic benefits in the field of industrial waste gas treatment.

Description

Technical Field

[0001] The present invention relates to the technical field of industrial waste gas treatment, and in particular to a method for treating VOCs waste gas at low temperature by adopting low-pressure electrocatalytic oxidation. Background Art

[0002] With the rapid development of industrialization, the emission of various volatile organic compounds in the production process has increased significantly, and VOCs have become an important pollutant that causes air pollution, photochemical smog and ozone layer depletion. The effective treatment of VOCs, especially the treatment under low temperature conditions, has become a key research topic in the current field of environmental protection and industrial waste gas treatment. The traditional thermal catalytic oxidation method requires high-temperature heating to treat VOCs, which not only increases energy consumption, but also has technical difficulties such as catalyst deactivation and equipment corrosion. In response to this problem, low-temperature catalytic oxidation has gradually gained attention. The advantages of low-temperature purification technology are to reduce heat loss, reduce operating costs, and effectively remove VOCs at lower temperatures. However, the current low-temperature purification technology generally has problems such as insufficient treatment efficiency, high equipment complexity, and difficulty in adapting to large-scale industrial applications. Therefore, it is of great significance to explore a VOCs purification method with high efficiency, low energy consumption and suitable for low temperature conditions.

[0003] Electrocatalytic oxidation technology drives the active species of catalysts to participate in the oxidation reaction of VOCs through the action of electric fields, and has the potential to complete waste gas purification at room temperature or low temperature. This technology is different from traditional thermal catalytic methods. It can achieve oxidative degradation of VOCs under the action of a low-voltage power supply, significantly reducing the energy consumption and operating temperature of the equipment, and has high economy and environmental friendliness. Using solid metal oxides as catalysts and stimulating their activity through low-voltage currents helps to improve the redox performance of the catalyst under low-temperature conditions, thereby achieving efficient purification. The current application of low-temperature electrocatalytic technology in VOCs purification is still in the exploratory stage, but its application prospects are broad. The innovative exploration of this application in the field of low-temperature electrocatalytic oxidation aims to provide an efficient and low-cost solution for industrial waste gas treatment. Summary of the invention

[0004] The purpose of the present invention is to solve the shortcomings of the prior art and to propose a low-temperature purification method for VOCs waste gas using low-voltage electrocatalytic oxidation. By adjusting the output voltage and current of the low-voltage power supply, the purification efficiency of VOCs can be flexibly controlled. It has the significant advantages of simple operation and low energy consumption.

[0005] In order to achieve the above object, the present invention adopts the following technical solutions: A method for treating low-temperature purification of VOCs waste gas by low-pressure electrocatalytic oxidation comprises the following steps: Step S1, filling a solid oxide catalyst into a ceramic tube; Step S2, connecting and fixing the positive and negative ends of the low-voltage power supply to the two ends of the catalyst in step S1 to form a current loop; Step S3, using an induced draft fan to introduce a certain concentration of VOCs waste gas into the ceramic tube in step S1; Step S4: By adjusting the power supply output voltage, VOCs can be purified at near room temperature.

[0006] Preferably, in step S1, the solid oxide is a mixed solid catalyst of one or more of noble metal-based oxides and non-noble metal oxides.

[0007] Preferably, the noble metal-based oxides are Ag / MnO2 and Pt / CeO2, and the non-noble metal oxides are one or more composites of MnO2, Co3O4, CuO, and CeO2.

[0008] Preferably, in step S2, the output voltage of the low-voltage power supply is 2-36V.

[0009] Preferably, in step S3, the concentration of VOCs is 0-5 g / m 3 .

[0010] Preferably, in step S4, the VOCs low-temperature purification temperature is 25~100°C, and the purification efficiency is 85%~99%.

[0011] By adopting the above technical solution: constructing a purification system with a low-voltage power supply, a solid metal oxide catalyst and an air supply fan as the core, the VOCs components in the exhaust gas are effectively removed through electrochemical reactions under low temperature conditions. Specifically, the purification system includes a ceramic tube filled with a solid oxide catalyst, a low-voltage power supply and an air supply fan; the positive and negative ends of the low-voltage power supply are connected to the two ends of the catalyst. Under the action of the electric field, the active species on the catalyst surface are excited and participate in the oxidation reaction of VOCs, thereby achieving efficient purification of VOCs under low temperature conditions. This method can flexibly control the purification efficiency of VOCs by adjusting the output voltage and current of the low-voltage power supply, and has the significant advantages of simple operation and low energy consumption.

[0012] Compared with the prior art, the present invention has the following beneficial effects: 1. The present invention utilizes low-voltage current to drive the active species of the catalyst to participate in the oxidation of VOCs under low temperature conditions without the need for external heating, thus breaking through the limitation of the traditional thermal catalytic oxidation method requiring high-temperature heating; since no complex high-temperature heating system is required, the equipment design and maintenance are simpler.

[0013] 2. The present invention can achieve VOCs oxidation at low temperature by adjusting the output voltage and current of the low-voltage power supply without high-temperature heating, which greatly reduces energy consumption and has the significant advantages of simple operation and low energy consumption.

[0014] 3. The present invention can achieve rapid degradation of VOCs through electrocatalysis and achieve high purification efficiency at low temperatures. The electrocatalytic oxidation technology will have good application prospects and economic benefits in the field of industrial waste gas treatment. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is the principle diagram of the present invention; Figure 2 The figure is a comparison result of the conversion efficiency and the conversion temperature of each embodiment and the comparative example in the present invention. DETAILED DESCRIPTION

[0016] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the accompanying drawings, so that those skilled in the art can better understand the advantages and features of the present invention, thereby making a clearer definition of the protection scope of the present invention. The embodiments described in the present invention are only a part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in the field without making creative work are within the scope of protection of the present invention.

[0017] Example 1 (1) A mixed metal oxide (e.g., a composite of CuO and CeO2) is selected as a catalyst and filled into a ceramic tube with an inner diameter of 10 mm.

[0018] (2) Connect the positive and negative electrodes of the power supply to the two ends of the catalyst and set the voltage to 2V.

[0019] (3) Introduce toluene waste gas with a concentration of 2 g / m³, and control the air flow rate to 100 mL / min through a fan.

[0020] (4) The ambient temperature of the reaction system is finally 100°C, and the purification rate of toluene reaches 85%.

[0021] Example 2 (1) Use Ag / MnO2 catalyst and fill it into a ceramic tube with an inner diameter of 15 mm.

[0022] (2) Connect the positive and negative poles of the power supply to both ends of the catalyst and adjust the low-voltage power supply output to 18V.

[0023] (3) Benzene exhaust gas with a concentration of 3 g / m³ was introduced, and the fan flow rate was set to 200 mL / min.

[0024] (4) The ambient temperature of the reaction system finally reached room temperature, 25°C, and the purification rate reached 92%.

[0025] Example 3 (1) Co3O4 was selected as the single catalyst and filled into a ceramic tube with an inner diameter of 12 mm.

[0026] (2) Connect the positive and negative electrodes of the power supply to both ends of the catalyst and adjust the voltage to 12V.

[0027] (3) Introduce acetone waste gas with a concentration of 1.5 g / m³ and a flow rate of 150 mL / min.

[0028] (4) The ambient temperature of the reaction system was finally 80°C, and the purification rate reached 99%.

[0029] Example 4 (1) A mixed catalyst of CuO and MnO2 was filled into a ceramic tube with an inner diameter of 20 mm.

[0030] (2) Connect the positive and negative electrodes of the power supply to both ends of the catalyst and adjust the voltage to 30V.

[0031] (3) Introduce n-hexane exhaust gas with a concentration of 4 g / m³ and an air flow rate of 120 mL / min.

[0032] (4) The ambient temperature of the reaction system was finally 50°C, and the purification rate reached 88%.

[0033] Example 5 (1) Use precious metal Pt and CeO2 composite oxide to fill a ceramic tube with a diameter of 18 mm.

[0034] (2) Connect the positive and negative electrodes of the power supply to both ends of the catalyst, and set the power supply voltage to 36V.

[0035] (3) The VOCs waste gas is a mixed component (toluene and acetone) with a total concentration of 3 g / m³ and an introduced air flow rate of 200 mL / min.

[0036] (4) The ambient temperature of the reaction system was finally 25°C, and the total purification rate of mixed VOCs reached more than 90%.

[0037] Comparative Example 1 (1) Using the same concentration of toluene waste gas, the traditional thermal catalytic oxidation method was selected for treatment (the catalyst was the mixture of CuO and CeO2 in Example 1), and the reaction temperature was set to 350°C.

[0038] (2) The purification efficiency is about 95%, but the energy consumption is high and the equipment maintenance is complicated.

[0039] Comparative Example 2 (1) Use a room temperature treatment method without electrocatalytic assistance, relying only on fan ventilation.

[0040] (2) The exhaust gas concentration is 2 g / m³, and all catalysts in the implementation example have no catalytic effect.

[0041] In summary, the present invention can achieve VOCs oxidation at low temperature by adjusting the output voltage and current of the low-voltage power supply without high-temperature heating, thereby greatly reducing energy consumption and having the significant advantages of simple operation and low energy consumption.

[0042] The description and practice disclosed in the present invention are easy to think and understand for ordinary technicians in the technical field, and several improvements and modifications can be made without departing from the principles of the present invention. Therefore, modifications or improvements made without departing from the spirit of the present invention should also be regarded as the protection scope of the present invention.

Claims

1. A method for treating low-temperature VOCs waste gas by low-pressure electrocatalytic oxidation, characterized in that: The steps include: Step S1, filling a solid oxide catalyst into a ceramic tube; Step S2, connecting and fixing the positive and negative ends of the low-voltage power supply to the two ends of the catalyst in step S1 to form a current loop; Step S3, using an induced draft fan to introduce a certain concentration of VOCs waste gas into the ceramic tube in step S1; Step S4: VOCs can be purified at room temperature by adjusting the power supply output voltage.

2. The method for treating low-temperature VOCs waste gas by low-pressure electrocatalytic oxidation according to claim 1, characterized in that: In step S1, the solid oxide is a mixed solid catalyst of one or more of noble metal-based oxides and non-noble metal oxides.

3. The method for treating low-temperature VOCs waste gas by low-pressure electrocatalytic oxidation according to claim 2, characterized in that: The noble metal-based oxides are Ag / MnO2 and Pt / CeO2, and the non-noble metal oxides are one or more composites of MnO2, Co3O4, CuO, and CeO2.

4. The method for treating low-temperature VOCs waste gas by low-pressure electrocatalytic oxidation according to claim 1, characterized in that: In step S2, the output voltage of the low voltage power supply is 2-36V.

5. The method for treating low-temperature VOCs waste gas by low-pressure electrocatalytic oxidation according to claim 1, characterized in that: In step S3, the concentration of VOCs is 0-5 g / m 3 .

6. The method for treating low-temperature VOCs waste gas by low-pressure electrocatalytic oxidation according to claim 1, characterized in that: In step S4, the VOCs low-temperature purification temperature is 25~100°C, and the purification efficiency is 85%~99%.

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