KR20210102909A - Catalyst application method on the surface of a catalytic combustion burner - Google Patents

Abstract

The present invention also relates to a method of applying a catalyst to the surface of a catalytic combustion burner, wherein the burner has an upper portion (10) comprising an inner surface (100), an outer surface (101), and an upper surface (102) in the form of a crown a method comprising an endpiece (1) comprising an endpiece (1) and a sleeve (2) arranged in an extension of said endpiece (1) and adapted to hold a wick for delivering a combustible composition to a burner. The method comprises the steps of A) impregnating the outer 101, and inner 100 or upper 102 surfaces with a catalyst composition comprising at least one catalyst corresponding to group 9 or 10 of the periodic table, and B) the burner. heat-treating to _a temperature Ta of at least 450°C. The catalyst composition according to the invention is a non-Newtonian fluid which exhibits a _{kinematic coefficient of viscosity μ c} of at least 15 mPa·s at 20° C. before application to the end piece 1 . The invention also relates to a catalytic combustion burner, which can be coated with a catalyst according to the process of the invention, and a catalytic combustion vessel containing a combustible liquid and suitable for receiving the catalytic combustion burner of the invention in its neck.

Description

Catalyst application method on the surface of a catalytic combustion burner

FIELD OF THE INVENTION The present invention relates generally to the field of catalytic combustion, and more particularly to the field of catalytic combustion burners made of porous materials. Said burners are used in particular for the diffusion of perfumes and/or active substances, the destruction of odorless and non-odorous molecules, and/or for air purification.

A burner of this kind has been disclosed, for example, in the French patent application FR 3,061,543 in the name of the applicant. It is more particularly a burner adapted to receive a wick immersed in a combustible liquid contained in a catalytic combustion vessel which houses the burner at its neck. A burner of this kind (shown in detail in FIG. 3a ) is made of a porous material and has an end piece having a cavity coming out of its upper part and having a cavity in its lower part to which the ends of the wick are connected. The end piece is extended by a sleeve at the bottom thereof. The outer surface of the top of the endpiece, and its upper surface (which is annular) are doped with a catalyst. The inner surface of the upper part of the end piece is advantageously treated the same. During operation, the flammable liquid delivered through the wick penetrates into the pores of the porous material of the burner. A portion of the liquid crosses the center of the burner and undergoes vaporization there.

However, burners of this kind are known to have disadvantages in doping which, in operation, result in an increase in the temperature in the central diffusion of the burner, which is detrimental to the olfactory quality when said burner is used to diffuse perfume.

In order to overcome the above-mentioned disadvantages, the applicant has developed a catalyst application method which prevents too high temperature in the center by better distributing the catalyst on the surface of the end piece of the burner.

Therefore, more particularly, the present invention relates to a method of applying a catalyst to the surface of a catalytic combustion burner,

The catalytic combustion burner is made of a porous material,

an end piece having an upper portion and a lower portion, the upper portion having an inner surface defining a cavity, an essentially cylindrical outer surface, and a peripheral sidewall comprising a crown-shaped upper surface, and

a sleeve disposed in an extension of said lower portion of said endpiece, said sleeve including a cavity adapted to hold a wick for delivering a combustible composition to a burner;

The method is

A) impregnating the outer surface and the inner surface of the end piece, the crown or the inner surface and the crown with a catalyst composition comprising at least one catalyst corresponding to group 9 or 10 of the periodic table;

B) heat-treating the burner impregnated with the catalyst at a temperature T _{a of at least 450° C.}

The method is characterized in that the catalyst composition is a non-Newtonian fluid which exhibits _{a kinematic viscosity μ c} of at least 15 mPa·s at ambient temperature prior to application on the end piece ( 1 ).

A Newtonian fluid is understood in the present invention to be a fluid whose viscosity does not depend on its shear rate and the time the liquid is sheared.

Advantageously, the catalyst composition comprises:

a catalyst selected from metals corresponding to groups 9 or 10 of the periodic table, in an amount of 1% to 5% by weight relative to the total weight of the catalyst composition, and

0.2% to 2% by weight relative to the total weight of the catalyst composition, comprising a compound capable of increasing the flow resistance of the catalyst composition.

A compound capable of increasing the flow resistance of a fluid is understood in the present invention to be a compound capable of causing the fluid to have a kinematic viscosity μc of at least 5 mPa·s at ambient temperature (ie approximately 20° C.).

The compound capable of increasing the flow resistance may preferably be a polymer derived from glucose or a polymer derived from ethylene oxide.

Heat treatment B) is advantageously at least three hours includes that the temperature is kept at T _a.

The invention also relates to a catalytic combustion burner which can be coated with a catalyst according to the process of the invention.

Finally, the present invention also relates to a catalytic combustion vessel suitable for receiving at its neck a catalytic combustion burner containing a combustible liquid and containing a wick immersed in said liquid, said vessel 20 comprising: is mounted

Other features and advantages of the present invention will become apparent from the detailed description thereof set forth below, without limitation in any way, by way of indication and indication with reference to the accompanying drawings:
1 schematically shows a photograph of an embodiment of a catalytic combustion burner with a catalyst, which burner may have been treated with the method of the invention by impregnation of the catalyst onto its surface;
Fig. 2 is a schematic diagram of an elevational view of the vessel equipped with the catalytic combustion burner of Fig. 1;
Fig. 3a is an IR thermogram generated to show the effect of application of catalyst on the surface of an end piece of a catalytic combustion burner treated by conventional application without air conditioning;
Fig. 3b is an IR thermogram generated to show the effect of application of catalyst on the surface of an end piece of a catalytic combustion burner treated by the method of the present invention without air conditioning;
Fig. 4a is an IR thermogram generated to show the effect of application of catalyst on the surface of an end piece of a catalytic combustion burner treated by conventional application in the presence of air conditioning;
Fig. 4b is an IR thermogram generated to show the effect of application of catalyst on the surface of an end piece of a catalytic combustion burner treated by the method of the present invention in the presence of air conditioning;
Figure 5 shows a protocol for measuring the effect of air conditioning on the temperature of the burner in operation with an infrared camera.

Common technical features of [FIG. 1] and [FIG. 2] are respectively indicated by the same numerical reference in the corresponding drawings.

3A, 3B, 4A, 4B, and 5 are described in the description part of the embodiment after the description of FIGS. 1 and 2 .

1 schematically shows a cross section of an embodiment of a catalytic combustion burner with a catalyst, said burner being capable of being treated by the method of the invention by impregnation of a catalyst onto its surface. This kind of burner 1 is made of a porous material, and its upper part 10 has a cavity (or reservoir) 100 coming out, and its lower part 11 has a cavity to which the end of the wick 40 is coupled. and an end piece (1) for retaining, said wick (40) comprising a combustible composition (30) (in the example below, isopropyl alcohol) from a container (20) having a burner (1) installed in its neck (5). to be delivered to the burner. The end piece 1 is extended at its lower part by a sleeve 2 (also called a barrel). FIG. 2 schematically shows an elevation view of a vessel 20 equipped with the burner 1 of FIG. 1 . The flammable liquid 30 is typically an alcohol, such as isopropyl alcohol, or any other suitable flammable liquid consistent with laws in force in the art. The flammable liquid 30 should, more particularly, ensure that its vaporization and its catalytic combustion do not emit any unpleasant odors. The flammable liquid 30 may further include a fragrance and/or an active material.

The wick 40 is any known wick, such as a wick made of, for example, cotton, or a wick made of a mineral material, eg, mineral fiber. In operation, the flammable liquid 30 from the vessel 20 rises by capillary action into the wick 40 and penetrates into the pores of the porous material of the burner, thereby carrying out catalytic combustion of the liquid when preheated. More particularly with respect to the upper portion 10 of the end piece 1 , the upper portion of the end piece has an inner, essentially cut face, essentially cylindrical outer face 101 defining a cavity in the form of a reservoir 100 . , and a peripheral sidewall comprising an upper surface 102 in the form of a crown.

The catalyst (not visible in FIGS. 1 and 2 ) can be prepared according to the method of the present invention (indicated in the Examples as “Burner BI”) or according to methods known to those skilled in the art (indicated in the Examples as “Burner BC”). It was applied to the outer surface 101 and the crown 102 of the end piece 1 . In the latter case, doping of the burner was carried out conventionally, and this burner was used as a control in the catalytic operation test without air conditioning.

For this purpose, to test the catalytic operation (with or without air conditioning) of the burner shown in FIG. 1 , said burner was placed in the catalytic combustion vessel 20 shown in FIG. 2 .

A burner 10 (the present invention shown in FIG. 5 or the prior art shown in FIG. 1 ) is installed (eg, by a metallic sheet disposed on the neck 50 ) at the neck 50 of the vessel. . The wick 40 is accommodated in the burner 10 , and the catalytic combustion wick 40 accommodates the wick 40 immersed in the liquid 30 . The vessel 20 may be any type of vessel having a neck 50 into which the burner 10 fits.

The examples are set forth below to illustrate the invention in conjunction with the above-mentioned drawings without limiting the scope of the invention.

In these examples, all percentages and ratios are expressed as mass percentages, unless otherwise indicated.

Example

Devices and compositions

Catalyst composition of the present invention

aqueous, alcoholic, or aqueous-alcoholic solvents;

catalyst:

The catalyst used (on any part 100, 101, or 102 of the burner) is a metal corresponding to group 9 or 10 of the periodic table. It is present in a proportion of 2% by weight, based on the weight of the catalyst composition of the present invention.

Compounds capable of increasing the flow resistance of the catalyst composition:

Polymer derived from 0.2% to 2% by weight of glucose relative to the total weight of the catalyst composition such that the kinematic viscosity coefficient μ _{c of the composition before application is approximately 20 mPa·s at 20°C.}

Control catalyst composition :

water,

catalyst,

The catalyst used (on any part 100, 101, or 102 of the burner) is a metal corresponding to group 9 or 10 of the periodic table. It is present in a proportion of 2% by weight relative to the weight of the control catalyst composition.

The composition of the porous material that makes up the burner :

Thermally conductive compound: silicon carbide (1%);

Refractory compound: Mullite (66.5%);

Binder: Glass (11.5%);

Pore former: polymethyl methacrylate (PMMA: 21.5%).

Burners used:

Comparative Example: Doping Using Control Catalyst Composition

Burner “BC” (shown in FIG. 1 ) was composed of the porous material obtained from composition C, and the burner surfaces 100, 101, and 102 were doped with a control catalyst composition impregnating them. The catalyst composition was applied onto the surfaces 100, 101, and 102 of the end pieces of the burner by impregnation and then hardened at a temperature of at least 450° C., and then maintained at this temperature for at least 3 hours.

Examples of the present invention: Doping using the catalyst composition of the present invention

Burner "B" (shown in Fig. 1) was composed of the porous material obtained from composition C, and the surfaces 100, 101, and 102 of the burners were doped with the catalyst composition of the present invention impregnating them. The catalyst composition was applied onto the surfaces 100, 101, and 102 of the end pieces of the burner by impregnation and then hardened at a temperature of at least 450° C., and then maintained at this temperature for at least 3 hours.

Containers used:

As shown in Figure 2 for burners "BI" (invention) and "BC" (comparison or control).

Wick used:

cotton wick.

Flammable liquids used:

isopropyl alcohol.

test and measurement

Measurement of the operating characteristics of the burners BI and BC installed in the vessel 20 in the presence of an air conditioner at 18° C. with and without ventilation:

The test protocol is shown in FIG. 5 . This is the temperature of each of the tested burners BI and BC operating in vessel 20 placed at a suitable distance from the low level air conditioner of FIGS. It generally consists of using an infrared thermometer (IR) with an IR thermal camera as an aid to measure the . The measurements were also compared to measurements performed without ventilation for each burner tested (Control 1C and Inventive 1 and 2).

The resulting thermogram is described in detail below:

- Control burner BC:

Without air conditioning: Fig. 3a,

Under air conditioning: FIG. 4A (top view).

- burners BI treated according to the method of the invention:

Without air conditioning: Fig. 3b,

Under air conditioning: FIG. 4B (top view).

Comparing the thermograms of FIGS. 3A and 3B, when the surfaces 100, 101, and 102 of the end pieces of the catalyst in the absence of air conditioning were treated with the method of the present invention, the temperature of the diffusion center of the burner was 389 It appears to decrease from °C (treated with control catalyst composition) to 364 °C.

Comparison of the thermograms of Figures 3a and 3b shows a similar effect in the presence of air conditioning: when the surfaces 100, 101, and 102 of the end pieces of the catalyst are treated with the method of the present invention, the central diffusion of the burner The negative temperature is reduced from 357°C (treated with control catalyst composition) to 318°C.

_{Through application by the method of the invention of a catalyst composition having a kinematic viscosity coefficient μ c} of 15 mPa.s at 20° C., the catalyst penetrates substantially less into the interior of the burner, such that the temperature of the central diffusion of the burner is lower than that of the control catalyst composition. lower than when applied.

Claims (6)

A method of applying a catalyst to the surface of a catalytic combustion burner, comprising:
The catalytic combustion burner is made of a porous material,
An end piece (1) having an upper portion (10) and a lower portion (11), said upper portion (10) having an inner surface (100) defining a cavity, an essentially cylindrical outer surface (101), and an upper surface in the form of a crown an end piece (1) having a peripheral sidewall comprising (102), and
a sleeve (2) disposed in an extension of said lower portion (11) of said end piece (1) and comprising a cavity suitable for holding a wick for delivering a combustible composition to a burner;
The method is
A) the outer surface 101 and the inner surface 100, the crown 102, or the inner surface 100 and the crown 102 of the end piece 1 at least one corresponding to group 9 or 10 of the periodic table impregnating in a catalyst composition comprising a catalyst of
B) heat-treating the burner impregnated with the catalyst at a temperature T _{a of at least 450° C.}
The method, characterized in that the catalyst composition is a non-Newtonian fluid which exhibits a _{kinematic coefficient of viscosity μ c} of at least 15 mPa·s at 20° C. before application to the end piece (1). According to claim 1, wherein the catalyst composition,
A catalyst selected from metals corresponding to groups 9 or 10 of the periodic table, in an amount of 1% to 5% by weight relative to the total weight of the catalyst composition, and 0.2% by weight to 2% by weight relative to the total weight of the catalyst composition, the catalyst composition A method comprising a compound capable of increasing the flow resistance of 3. The method of claim 2, wherein the compound is capable of increasing the flow resistance of glucose-derived polymers and ethylene oxide-derived polymers. 4. The method according to any one of claims 1 to 3, wherein the thermally treating step of B) comprises maintaining said temperature in Ta for at least 3 hours. A catalytic combustion burner coated with a catalyst applied according to the method as defined in any one of claims 1 to 4. A catalytic combustion vessel (20) suitable for receiving at its neck (50) a catalytic combustion burner containing a flammable liquid (30) and having a wick (40) immersed in said liquid (30), said vessel (20) A catalytic combustion vessel (20), characterized in that (20) is equipped with a burner (10) as defined according to claim 5 .

Images