CN206483453U - A kind of low-temperature plasma modified catalyst device - Google Patents

Abstract

The utility model relates to a low-temperature plasma modified catalyst device. The device comprises a quartz tube, a high-voltage electrode and a grounding electrode. The high-voltage electrode is connected to the quartz tube through a polytetrafluoroethylene sleeve, and the grounding electrode is wrapped on the outer surface of the quartz tube. The ground wire is connected, and the high-voltage electrode is a stainless steel rod placed on the axis of the quartz tube, which is connected with a high-frequency AC power supply; the discharge area of the quartz tube is filled with catalyst. Loading the catalyst in the low-temperature plasma modification catalyst device for modification has the advantages of simple operation, short process, easy to realize automatic control, good stability, clean and pollution-free, etc. It is a short time, low temperature, and low energy consumption. process; in the utility model device, the catalytic activity of the modified catalyst is better, and the modified catalyst has a higher catalytic oxidation activity of methyl sulfide, and the catalytic oxidation efficiency at 360 ° C can reach more than 90%; the utility model It is convenient for actual production and application, and has high industrial application value.

Description

A low-temperature plasma modification catalyst device

technical field

The utility model relates to a low-temperature plasma modified catalyst device, which belongs to the technical field of low-temperature plasma modified catalysts applied to air pollution purification.

Background technique

Volatile Organic Compounds (Volatile Organic Compounds, hereinafter referred to as VOCs) refer to any organic compound with a boiling point lower than 250°C under normal pressure, or a saturated vapor pressure exceeding 133.32Pa at room temperature (25°C), which is emitted in the form of gaseous molecules The general term for all organic compounds in the air. Since various VOCs related products and raw materials are widely used in industrial production and people's daily life, they become important sources of secondary pollutants such as O ₃ and PM _2.5 , organic aerosols, etc. Precursor.

A certain concentration and quality of VOCs have a serious impact on the atmospheric environment and human health. Traditional VOCs treatment technologies include absorption method, condensation method, adsorption method, combustion method, catalytic oxidation method, biodegradation method, adsorption-solvent recovery method and adsorption-catalytic combustion method. Among them, the catalytic oxidation method can treat low-concentration VOCs gas at a temperature much lower than that of direct combustion. It has the characteristics of high purification efficiency, no secondary pollution, and low energy consumption. It is one of the most effective treatment methods for commercial VOCs applications. one.

Improving catalyst efficiency is of great significance for improving VOCs catalytic oxidation technology. In order to improve the efficiency of the catalyst, it is necessary to uniformly disperse the active components on the carrier. The active components and the carrier cooperate and influence each other to jointly promote the chemical reaction. When the preparation methods are different, the structural characteristics and chemical properties of the catalysts are different, which ultimately leads to the difference in catalytic activity. Traditional catalyst preparation mainly introduces metal precursors onto the surface of the carrier by impregnation, ion exchange, co-precipitation and other methods, and then is dried and calcined to load the active metal components on the surface of the carrier. In the conventional calcination heat treatment process, the preparation time is longer and the preparation temperature is higher, the surface structure of the catalyst may be destroyed, sintering occurs, and the activity and stability are poor. There are still many areas to be improved in the catalyst preparation process, such as improving catalytic activity, increasing lifespan, and reducing preparation costs.

Utility model content

In order to overcome the shortcomings of the prior art, the utility model provides a low-temperature plasma modification catalyst device.

A low-temperature plasma modification catalyst device, the device includes a quartz tube, a high-voltage electrode and a grounding electrode, the high-voltage electrode is connected to the quartz tube through a polytetrafluoroethylene sleeve, the grounding electrode is wrapped on the outer surface of the quartz tube, and connected to the ground wire , the high-voltage electrode is a stainless steel rod placed on the axis of the quartz tube, which is connected to a high-frequency AC power supply; the discharge area of the quartz tube is filled with catalyst.

Preferably, one end of the quartz tube is provided with an air inlet, and the other end is provided with an air outlet.

Preferably, the inner diameter of the quartz tube is 20mm, and the outer diameter is 25mm.

Preferably, the effective length of the discharge area of the quartz tube is 100 mm.

Preferably, the diameter of the high-voltage electrode is 1.6mm.

Preferably, the device is a cylindrical media barrier reactor.

There are a large number and a wide variety of active particles in low-temperature plasma, which are more active than those produced by common chemical reactions and are more active, and are more likely to react with the surface of the material they are in contact with, so they can be used to Modification of catalyst surface. When the plasma is applied to the modified catalyst, due to the low temperature, the modification of the catalyst only involves the surface, which can effectively inhibit the aggregation of particles and avoid problems such as agglomeration caused by the thermal effect of calcination. The active substances in the plasma can be in the The activity of the prepared catalyst is often enhanced by removing the substances in the catalyst precursor at low temperature and increasing the surface roughness and specific surface area.

Compared with the prior art, the utility model has the beneficial effects of:

The low-temperature plasma modified catalyst device adopted by the utility model is a cylindrical dielectric barrier reactor. The plasma modified catalyst treatment process is easy to operate, short in flow, easy to realize automatic control, good in stability, clean and pollution-free, and is a time-consuming Short process, low temperature and low energy consumption; the catalytic activity of the catalyst prepared by the device of the utility model is better, the modified catalyst has a higher catalytic oxidation activity of methyl sulfide, and the catalytic oxidation efficiency at 360 ° C can reach 90% Above; the utility model is convenient for actual production and application, and has high industrial application value.

Description of drawings

Fig. 1 is a structural schematic diagram of a low-temperature plasma modification catalyst device of the present invention.

detailed description

The utility model will be further described below in conjunction with the accompanying drawings and specific embodiments, but the scope of protection of the utility model is not limited thereto.

With reference to Fig. 1, a kind of low-temperature plasma modification catalyst device, described device comprises quartz tube 4, high-voltage electrode 3 and grounding electrode 2, and quartz tube 4 is as the container and insulating medium of placing catalyst, and internal diameter is 20mm, and external diameter is 25mm The high-voltage electrode 3 is connected to the quartz tube 4 through a polytetrafluoroethylene sleeve 8, and the ground electrode 2 is a piece of copper, which is wrapped on the outer surface of the quartz tube 4 and connected to the ground wire. The high-voltage electrode 3 is a piece placed on the quartz tube. The stainless steel rod of the tube axis has a diameter of 1.6 mm, which is connected to the high-frequency AC power source 1; the discharge area of the quartz tube 4 is filled with a catalyst 6, and the effective length of the discharge area of the quartz tube is 100 mm. One end of the quartz tube 4 is provided with an air inlet 5 and the other end is provided with an air outlet 7 .

Preparation of catalyst precursor:

Weigh a certain amount of manganese nitrate and cerium nitrate, add deionized water to dissolve and stir for 2 hours, and configure a 0.1mol/L solution; measure an appropriate amount of citric acid, add deionized water and mix and stir for 2 hours; mix the precursor solution and citric acid solution Mix and stir for 2 hours, the molar ratio of citric acid to metal cations is 1.5:1; stir and mix the mixed solution thoroughly and place it in a water bath at 80°C for 3 hours to wet gel; put the obtained sample in an oven at 110 Dry at ℃ for 12 hours; grind the dried sample into 40-60 mesh to obtain a Mn-Ce catalyst precursor, wherein the molar ratio of Mn:Ce is 3:1;

Preparation of plasma-modified catalyst:

Take 0.2g of the Mn-Ce catalyst precursor sample and put it in the low-temperature plasma modified catalyst device, pass Ar, the ventilation rate is 100ml/min, turn on the high-frequency AC power supply, use low-temperature plasma to treat the catalyst, and the discharge frequency is constant at 10kHz , the discharge power is 20W, and the discharge time is 60min respectively; the modified catalyst precursor is put into a muffle furnace and heated to 500°C at a heating rate of 5°C/min, and then calcined in air at 500°C for 5h to obtain The catalyst is Mn-Ce-20W-30min;

Catalytic oxidation of methyl sulfide (catalyst activity evaluation):

Catalyst activity evaluation was carried out in a miniature fixed-bed reactor. The reactor was a quartz glass reaction tube with an inner diameter of 8 mm and a length of 250 mm. The reactor was heated externally by a tubular resistance furnace. Controller control; the whole experimental system is composed of gas distribution part, catalytic reaction part and flue gas analysis and testing part;

Take 0.1g of catalyst and put it into the reactor, feed the initial concentration of 300ppm methyl sulfide, 5% O ₂ , the balance gas is N ₂ , the total flow rate of the mixed gas is 200ml, and the space velocity is 120,000h ^-1 . The reactor was placed in a tube furnace to program the temperature, and the infrared detector was used to measure the concentration change of methyl sulfide before and after the catalytic reaction, and the conversion efficiency was calculated. The conversion efficiency of methyl sulfide can reach 90% at 360°C.

Claims (6)

1. A low-temperature plasma modified catalyst device, characterized in that: the device comprises a quartz tube, a high-voltage electrode and a grounding electrode, the high-voltage electrode is connected to the quartz tube through a polytetrafluoroethylene sleeve, and the grounding electrode is wrapped on the outer surface of the quartz tube , connected to the ground wire, the high-voltage electrode is a stainless steel rod placed on the axis of the quartz tube, which is connected to a high-frequency AC power supply; the discharge area of the quartz tube is filled with a catalyst. 2. The low-temperature plasma reforming catalyst device according to claim 1, characterized in that: one end of the quartz tube is provided with an air inlet, and the other end is provided with an air outlet. 3. The low-temperature plasma reforming catalyst device according to claim 1, characterized in that: the inner diameter of the quartz tube is 20 mm, and the outer diameter is 25 mm. 4. The low-temperature plasma reforming catalyst device according to claim 1, characterized in that: the effective length of the discharge area of the quartz tube is 100 mm. 5. The low-temperature plasma reforming catalyst device according to claim 1, characterized in that: the diameter of the high-voltage electrode is 1.6 mm. 6. The low-temperature plasma modification catalyst device according to claim 1, characterized in that: the device is a cylindrical dielectric barrier reactor.