CN110314531A - A kind of VOCs absorption-electrically heated catalytic coupling function component and preparation method thereof - Google Patents

Abstract

The invention relates to a VOCs adsorption-electrothermal catalysis coupling functional component and a preparation method thereof. The component uses a PTC resistor as a skeleton, and a VOCs thermal catalyst is loaded on the PTC resistor. It is obtained by preparing a base coating on the surface of the PTC resistor, and then loading the VOCs thermal catalyst on the surface of the base coating of the PTC resistor. The invention realizes the direct thermal catalytic decomposition of VOCs in the temperature range of 200 to 300°C by loading the VOCs thermal catalyst on the constant temperature heating PTC resistance, which greatly reduces the energy consumption compared with the traditional split resistance wire heating air catalytic decomposition of VOCs , improves the energy utilization rate, improves the safety at the same time, and has good economic benefits. The preparation process of the invention is simple, and the obtained workpiece module is small and exquisite, and has high thermal efficiency, and can be applied to devices such as household air purifiers, fresh air purifiers, range hoods and the like, and has good application prospects.

Description

A VOCs adsorption-electrothermal catalysis coupling functional component and its preparation method

technical field

The invention relates to the field of organic matter purification, in particular to a VOCs adsorption-electrothermal catalysis coupling functional component and a preparation method thereof.

Background technique

VOCs (Volatile Organic Compounds) Building decoration materials will release volatile organic compounds (VOCs), and the release period is as long as several years. The World Health Organization (WHO) research shows that long-term exposure to high-risk VOCs containing formaldehyde and benzene series may cause cancer and leukemia. There are many types of VOCs in the home air, and the sources include the release of decoration materials and furniture, kitchen fume and so on.

At present, the purification of VOCs in indoor air mainly adopts the activated carbon adsorption method, which has the advantages of being able to adsorb a variety of gases, being cheap, and easy to use, but the disadvantages are also obvious. The harmful gases adsorbed are easy to desorb and cause secondary pollution, and activated carbon It has high water absorption, and the internal micropores are easy to absorb moisture and block. The actual purification life is only a few months. In the rainy season, the air is humid, and the life is only a few weeks. The release of VOCs in home decoration materials lasts for several years or even ten years. Activated carbon Obviously not meeting the requirements.

Catalytic method can decompose VOCs into carbon dioxide and water, which is considered to be an ideal method for purifying VOCs. There are photocatalytic and thermal catalytic oxidation methods commonly used, but photocatalytic decomposition is slow and has many by-products, so it is difficult to be effectively promoted.

Industrial thermal catalytic combustion technology can effectively catalyze and decompose VOCs. Through the efforts of scientists, the temperature of VOCs thermally decomposed by catalysts has been reduced to between 200°C and 300°C. However, the heating source in the prior art generally uses a resistance wire with a surface temperature above 1000°C. , using a blower to blow air through the resistance wire to heat the surface, and the high-temperature air passes through the catalyst module to decompose VOCs. The temperature of this type of device is too high, and the thermal efficiency is too low, so it cannot be applied in a household air purifier with plastic components as the main structure.

Contents of the invention

In view of the problems existing in the prior art, the present invention provides a VOCs adsorption-electrothermal catalysis coupling functional component and its preparation method. The PTC resistance heating body is heated at a constant temperature and has the characteristics of constant temperature at a certain fixed temperature. It is used as a skeleton, The surface is coated with a catalyst, and the PTC skeleton is heated by electricity to achieve direct thermal catalytic decomposition of VOCs in the temperature range of 200 to 300 ° C, which improves energy utilization and greatly reduces energy consumption. It also has the advantages of safety and energy saving, and has good economic benefits and applications. prospect.

For reaching this purpose, the present invention adopts following technical scheme:

In the first aspect, the present invention provides a VOCs adsorption-electrothermal catalysis coupling functional assembly, the assembly uses a PTC resistor as a skeleton, and loads a VOCs thermal catalyst on the PTC resistor.

According to the present invention, the constant temperature range of the PTC resistor is 100-400°C, preferably 200-300°C; for example, it can be 100°C, 150°C, 200°C, 250°C, 300°C, 350°C or 400°C, and the above The specific point values between the numerical values are limited in space and for the sake of simplicity, the present invention will not list them exhaustively.

According to the present invention, the PTC resistor is in the shape of a flat plate, a round tube or a porous honeycomb.

According to the present invention, the VOCs thermal catalyst is a noble metal catalyst.

According to the present invention, the noble metal catalyst includes an active component and a carrier.

According to the present invention, the active component is any one or a combination of at least two of platinum, palladium, rhodium, gold or silver; for example, it can be any one of platinum, palladium, rhodium, gold or silver, typically But non-limiting combinations are: platinum and palladium, rhodium and gold, platinum and silver, gold and silver, platinum, palladium and gold, platinum, palladium, rhodium and gold, etc. In consideration of brevity, the present invention is not exhaustively listed.

According to the present invention, the carrier is any one of alumina, titania or silica powder.

In the second aspect, the present invention provides a method for preparing the VOCs adsorption-electrothermal catalysis coupling functional component as described in the first aspect, the method comprising the following steps:

(1) prepare base coating on PTC resistance surface;

(2) loading the VOCs thermal catalyst on the surface of the base coat of the PTC resistor obtained in step (1).

According to the present invention, the specific operation of step (1) is: mixing the carrier powder, water and carrier sol, coating on the surface of the PTC resistor after ultrasonic cleaning, drying and calcining to obtain a base coating on the surface of the PTC resistor.

The carrier in the above-mentioned carrier powder and carrier sol is the corresponding carrier in the noble metal catalyst. For example, when the noble metal catalyst is based on alumina, the carrier powder is alumina powder, and the carrier sol is aluminum sol; when the noble metal catalyst is based on When silicon oxide is used as the carrier, the carrier powder is silicon oxide powder, and the carrier sol is silica sol; similarly, when the noble metal catalyst uses titanium oxide as the carrier, the carrier powder is titanium oxide powder, and the carrier sol is titanium sol.

The present invention does not specifically limit the amount of water added in the above-mentioned mixing process. The addition of water mainly serves as a dilution effect, and the amount of water added should be selected and adjusted according to the specific conditions in the actual operation process.

In the present invention, before coating the VOCs thermal catalyst on the surface of the PTC resistor, a base coat is prepared on the surface of the PTC resistor, and the base coat can increase the binding force between the PTC resistor and the VOCs thermal catalyst, so that the two can be firmly combined to avoid decomposition of VOCs at a constant temperature fall off in the process. Since the catalyst contains precious metals, the cost is relatively high. For the purpose of reducing costs, the base coating is prepared by mixing carrier powder and carrier sol without adding catalyst (noble metal).

According to the present invention, the mass ratio of the carrier powder and the carrier sol is (1-2):1, for example, it can be 1:1, 1.1:1, 1.2:1, 1.3:1, 1.4:1, 1.5:1, 1.6:1, 1.7:1, 1.8:1, 1.9:1 or 2:1, as well as specific point values between the above values, are limited in space and for the sake of brevity, the present invention will not list them exhaustively.

According to the present invention, the calcination temperature is 400-800°C, preferably 600°C; for example, it can be 400°C, 450°C, 500°C, 550°C, 600°C, 650°C, 700°C, 750°C or 800°C, As well as the specific point values between the above numerical values, the present invention will not list them exhaustively due to space limitation and for the sake of simplicity.

According to the present invention, the calcination time is 0.5-2h, preferably 1h; for example, it can be 0.5h, 1h, 1.5h or 2h, and the specific points between the above values are limited by space and for the sake of simplicity, The present invention is not exhaustively listed.

According to the present invention, the specific operation of step (2) is: after mixing the VOCs thermal catalyst, water and carrier sol, apply to the surface of the base coating of the PTC resistance obtained in step (1), dry and then calcinate, and then apply it on the surface of the PTC resistance A catalyst coating is obtained.

The carrier in the above-mentioned carrier sol is the corresponding carrier in the noble metal catalyst. For example, when the noble metal catalyst uses alumina as a carrier, the above-mentioned carrier sol is aluminum sol; when the noble metal catalyst uses silicon oxide as a carrier, the above-mentioned carrier sol is Silica sol; when the noble metal catalyst is supported by titanium oxide, the above-mentioned carrier sol is titanium sol.

The present invention does not specifically limit the amount of water added in the above-mentioned mixing process. The addition of water mainly serves as a dilution effect, and the amount of water added should be selected and adjusted according to the specific conditions in the actual operation process.

According to the present invention, the mass ratio of the VOCs thermal catalyst and carrier sol is (3-10):1; for example, it can be 3:1, 4:1, 5:1, 6:1, 7:1, 8:1 , 9:1 or 10:1, and specific point values between the above-mentioned numerical values, the present invention will not list them exhaustively due to space limitation and for the sake of brevity.

According to the present invention, the calcination temperature is 400-800°C, preferably 600°C; for example, it can be 400°C, 450°C, 500°C, 550°C, 600°C, 650°C, 700°C, 750°C or 800°C, As well as the specific point values between the above numerical values, the present invention will not list them exhaustively due to space limitation and for the sake of simplicity.

According to the present invention, the calcination time is 1-3h, preferably 2h; for example, it can be 1h, 1.5h, 2h, 2.5h or 3h, and the specific point values between the above values are limited to the length of the text and for the sake of brevity In consideration, the present invention is not exhaustively enumerated.

As a preferred technical solution, the preparation method of the VOCs adsorption-electrothermal catalysis coupling functional component of the present invention comprises the following steps:

(1) Mix the carrier powder, water and carrier sol, apply the resulting mixture to the surface of the PTC resistor after ultrasonic cleaning, dry and calcinate at 400-800°C for 0.5-2h, and obtain a base coating on the surface of the PTC resistor; The mass ratio of the carrier powder and the carrier sol is (1-2): 1;

(2) Mix the VOCs hot catalyst, water and carrier sol, and apply the resulting mixture to the surface of the base coating of the PTC resistor obtained in step (1), after drying, calcinate at 400-800°C for 1-3h, and then apply A catalyst coating is obtained on the surface of the resistance; the mass ratio of the VOCs thermal catalyst to the carrier sol is (3-10):1.

Compared with the prior art solutions, the present invention has at least the following beneficial effects:

(1) The present invention uses the PTC resistor as the skeleton, and by loading the VOCs thermal catalyst on the constant temperature heating PTC resistor, it realizes the direct thermal catalytic decomposition of VOCs in the temperature range of 200 to 300 ° C, which is different from the traditional split resistance wire heating air catalytic decomposition (The surface temperature is above 1000°C), which greatly reduces the energy consumption, improves the energy utilization rate, improves the safety at the same time, and has good economic benefits.

(2) The preparation process of the present invention is simple, the obtained workpiece module is small and exquisite, and has high thermal efficiency, and can be applied to devices such as household air purifiers and household range hoods, and has good application prospects.

Description of drawings

Fig. 1 is the physical figure of the PTC resistance skeleton that the specific embodiment of the present invention part uses;

Fig. 2 is the schematic plan view of the PTC resistance skeleton that the specific embodiment of the present invention part uses;

Fig. 3 is a physical diagram of the VOCs adsorption-electrothermal catalysis coupling functional assembly obtained in Example 1 of the present invention;

4 is a schematic structural view of a honeycomb unit in the VOCs adsorption-electrothermal catalysis coupling functional assembly obtained in Example 1 of the present invention, wherein, 1-honeycomb PTC resistance, 2-base coating, 3-catalyst coating;

Fig. 5 is a schematic diagram of the effect of catalytic conversion of ethyl acetate by the VOCs adsorption-electrothermal catalytic coupling functional component obtained in Example 1 of the present invention;

Fig. 6 is a schematic diagram of the purification effect of o-xylene by the air purification device composed of VOCs adsorption-electrothermal catalytic coupling functional components obtained in Example 1 of the present invention.

The present invention will be further described in detail below. However, the following examples are only simple examples of the present invention, and do not represent or limit the protection scope of the present invention, and the protection scope of the present invention shall be determined by the claims.

Detailed ways

The technical solutions of the present invention will be further described below in conjunction with the accompanying drawings and through specific implementation methods.

For better illustrating the present invention, facilitate understanding technical scheme of the present invention, typical but non-limiting embodiment of the present invention is as follows:

The constant-temperature heating PTC resistance framework selected in the specific embodiment of the present invention is a honeycomb porous cylinder, as shown in Figure 1, with an outer diameter of 41mm, a height of 10mm, and a volume of 13.2mL.

Example 1

(1) Mix alumina powder, water and aluminum sol evenly to obtain a mixed solution, the mass ratio of alumina powder and aluminum sol is 2:1, apply the obtained mixed solution to the surface of the PTC resistor after ultrasonic cleaning, and dry at 140°C , and then calcined at 600 ° C for 1 h to obtain a base coating on the surface of the PTC resistor;

(2) Mix Pd/AL ₂ O ₃ catalyst (Pd 1wt%), water and aluminum sol to obtain a mixed solution, the mass ratio of VOCs thermal catalyst and aluminum sol is 5:1, and apply the obtained mixed solution evenly to the step (1) The surface of the base coating of the obtained PTC resistor was dried at 140°C, and then calcined at 600°C for 2 hours to obtain a catalyst coating on the surface of the PTC resistor, that is, a VOCs adsorption-electrothermal catalytic coupling functional component. The structure of the obtained component is shown in the figure 3 and Figure 4.

Example 2

(1) Mix alumina powder, water and aluminum sol evenly to obtain a mixed solution. The mass ratio of alumina powder and aluminum sol is 1:1. Apply the resulting mixed solution to the surface of the PTC resistor after ultrasonic cleaning, and dry at 140°C , and then calcined at 500°C for 1.5h to obtain a base coating on the surface of the PTC resistor;

(2) Mix the Pt/AL ₂ O ₃ catalyst (Pt 1wt%), water and aluminum sol evenly to obtain a mixed solution, the mass ratio of the VOCs thermal catalyst and the aluminum sol is 4:1, and apply the obtained mixed solution evenly to the step (1) The surface of the base coating of the obtained PTC resistor was dried at 140°C, and then calcined at 650°C for 1.5h to obtain a catalyst coating on the surface of the PTC resistor, that is, a VOCs adsorption-electrothermal catalytic coupling functional component.

Example 3

(1) Mix silicon oxide powder, water and silica sol evenly to obtain a mixed solution. The mass ratio of silicon oxide powder and silica sol is 3:2. Apply the obtained mixed solution to the surface of the PTC resistor after ultrasonic cleaning, and dry at 140°C , and then calcined at 800°C for 0.5h to obtain a base coating on the surface of the PTC resistor;

( ₂ ) Rh/SiO Catalyst (Rh 1wt%), water and silica sol are mixed homogeneously to obtain mixed solution, the mass ratio of VOCs thermal catalyst and silica sol is 8:1, gained mixed solution is evenly coated on step (1 ) on the surface of the base coating of the PTC resistor, dried at 140°C, and then calcined at 500°C for 2.5h to obtain a catalyst coating on the surface of the PTC resistor, that is, a VOCs adsorption-electrothermal catalytic coupling functional component.

Performance Testing:

(1) Test the catalytic performance of VOCs adsorption-electrothermal catalytic coupling functional components

Place the VOCs adsorption-electrothermal catalysis coupling functional assembly obtained in Example 1 in a glass tube reactor, measure the surface temperature with a point thermometer, the catalytic gas is ethyl acetate, the initial concentration is 1000ppm, and the gas flow rate is 300mL/min, by changing Input the voltage, adjust the surface temperature of the functional components, and test the conversion rate of ethyl acetate at different temperatures. As shown in Figure 5, the conversion rate of ethyl acetate reaches more than 90% at 205°C.

(2) In the 3m ³ experimental cabin, test the purification effect of the air purification device on o-xylene

Take 16 VOCs adsorption-electrothermal catalysis coupling functional components obtained in Example 2, with a total volume of 211.2mL, divide them into 4 layers, and make 4 pieces in each layer to make VOCs adsorption-electrothermal catalysis coupling functional components, and select the adjustable air volume fan and VOCs adsorption -Electrothermal catalytic coupling functional components are assembled into a set of air purification device, the components are energized with AC 220V, the control current is 0.12A, the surface temperature is 290°C, and the air volume is adjusted to an air speed of 50000h ^-1 , according to GB/T 18801 "Air Purifier" standard, test the purification effect of the device on o-xylene in a 3m ³ airtight cabin, as shown in Figure 6, with the prolongation of the treatment time, the concentration of o-xylene gradually decreases, and drops below 0.2mg/m ³ after 6h .

The preferred embodiments of the present invention have been described in detail above, but the present invention is not limited to the specific details in the above embodiments. Within the scope of the technical concept of the present invention, various simple modifications can be made to the technical solutions of the present invention. These simple modifications All belong to the protection scope of the present invention.

In addition, it should be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable way if there is no contradiction. The combination method will not be described separately.

In addition, various combinations of different embodiments of the present invention can also be combined arbitrarily, as long as they do not violate the idea of the present invention, they should also be regarded as the disclosed content of the present invention.

Claims (10)

1. a kind of VOCs absorption-electrically heated catalytic coupling function component, which is characterized in that the component, will using PTC resistor as skeleton VOCs thermocatalyst is supported on the PTC resistor.

2. component as described in claim 1, which is characterized in that the constant temperature section of the PTC resistor is 100-400 DEG C, preferably It is 200-300 DEG C；

Preferably, the PTC resistor is tabular, circular tube shaped or porous honeycomb.

3. component as claimed in claim 1 or 2, which is characterized in that the VOCs thermocatalyst is noble metal catalyst.

4. the method according to claim 1, which is characterized in that the noble metal catalyst include active component and Carrier；

Preferably, the active component be platinum, palladium, rhodium, gold or silver in any one or at least two combination；

Preferably, the carrier is any one in aluminium oxide, titanium oxide or silicon oxide powder.

5. VOCs absorption according to any one of claims 1-4-electrically heated catalytic coupling function component preparation method, feature It is, the described method comprises the following steps:

(1) base coating is prepared on PTC resistor surface；

(2) VOCs thermocatalyst is supported on to the base coating surface for the PTC resistor that step (1) obtains.

6. method as claimed in claim 5, which is characterized in that the concrete operations of step (1) are as follows: by support powder, water and load It is coated to the PTC resistor surface by ultrasonic cleaning after the mixing of body colloidal sol, is calcined after dry, is obtained on PTC resistor surface Base coating.

7. method as claimed in claim 6, which is characterized in that the mass ratio of the support powder and carrier colloidal sol is (1-2): 1；

Preferably, the temperature of the calcining is 400-800 DEG C, preferably 600 DEG C；

Preferably, the time of the calcining is 0.5-2h, preferably 1h.

8. such as the described in any item methods of claim 5-7, which is characterized in that the concrete operations of step (2) are as follows: urge VOCs heat It is coated to the base coating surface for the PTC resistor that step (1) obtains after agent, water and the mixing of carrier colloidal sol, is forged after dry It burns, obtains catalyst coat on PTC resistor surface.

9. method according to claim 8, which is characterized in that the mass ratio of the VOCs thermocatalyst and carrier colloidal sol is (3-10):1；

Preferably, the temperature of the calcining is 400-800 DEG C, preferably 600 DEG C；

Preferably, the time of the calcining is 1-3h, preferably 2h.

10. such as the described in any item methods of claim 5-9, which is characterized in that the described method comprises the following steps:

(1) support powder, water and carrier colloidal sol are mixed, gained mixed liquor is coated to the PTC resistor table by ultrasonic cleaning Face calcines 0.5-2h at 400-800 DEG C after dry, obtains base coating on PTC resistor surface；The support powder and carrier The mass ratio of colloidal sol is (1-2): 1；

(2) VOCs thermocatalyst, water and carrier colloidal sol are mixed, gained mixed liquor is coated to the PTC resistor that step (1) obtains Base coating surface, calcine 1-3h at 400-800 DEG C after dry, obtain catalyst coat on PTC resistor surface；It is described The mass ratio of VOCs thermocatalyst and carrier colloidal sol is (3-10): 1.