JP2014151265A - Catalyst for fan heater, and fan heater - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a catalyst for a fan heater and the fan heater, which enable: generation rates of hydrocarbon (hereinafter referred to as HC) gases and nitrogen oxide (hereinafter referred to as NOx) gases to be suppressed; and a favorable combustion state to be confirmed.SOLUTION: A catalyst for a fan heater is characterized by including a cerium oxide, a fan heater includes a combustion apparatus that includes: a burner head having a flame hole at a side face; and a flame hole mesh that is disposed to the burner head to cover the flame hole, and the fan heater is characterized in that the catalyst including the cerium oxide is fixed to a surface of the flame hole mesh.

Description

  The present invention relates to a fan heater catalyst and a fan heater, and more specifically, hydrocarbon gas (hereinafter referred to as HC) and nitrogen oxide (hereinafter referred to as NOx) gas, which are problems specific to the fan heater. By providing the fan heater catalyst that can suppress the occurrence of the above and confirm the good combustion state particularly required for the fan heater, and the fan heater catalyst, the HC fuel odor and the operation that are generated when the operation is stopped The present invention relates to a fan heater that can suppress generation of NOx gas at the time and can confirm a good combustion state during operation.

  The fan heater is widely known as a heater.

  A fan heater, for example, an oil fan heater, has a bottomed cylindrical vaporization cylinder having an opening, a vaporization heater that heats the vaporization cylinder, a fuel pipe that sends fuel to the vaporization cylinder, and air sent to the vaporization cylinder A blower pipe for atomizing the fuel, a burner head which is installed so as to cover the opening of the vaporizing cylinder and has a flame hole on its side surface, and a flame hole network which is arranged on the burner head so as to cover the flame hole And a flame is generated from the flame hole when the fan heater is operated.

Even after the operation of the fan heater is stopped and the fuel supply is stopped, in order to expel the internal heat, the air blowing to the vaporizing cylinder by the air blowing pipe is continued for a certain time. At this time, the fuel vaporized by the residual heat does not burn, and therefore the vaporized fuel is not decomposed into CO ₂ and H ₂ O, and HC is released as unburned gas to the vicinity of the fan heater. As a result, when the operation of the fan heater is stopped, the fuel odor is generated as a bad odor over a period of time.

  In addition, when fossil fuel such as petroleum is flame-combusted with air, it is known that when the flame part reaches a high temperature state of 1400 ° C. or higher, nitrogen and oxygen in the air are combined to generate NOx, Even during operation of the fan heater, a low concentration of NOx is generated due to an increase in flame temperature.

  On the other hand, NOx is a substance harmful to the human body, as it is subject to exhaust gas regulations for automobiles, and causes a wide range of air pollution and damage to the human body by causing photochemical reaction and binding with fine particles. It is known to be a substance. In addition, HC gives off a strong odor and causes discomfort to humans. Therefore, in a fan heater that is generally used indoors, it is necessary to suppress the generation of HC and NOx.

  In addition, when the fan heater is operated, it is necessary to confirm a good combustion state. More specifically, the generation of red light due to the heating of the flame network is suppressed by lowering the heating temperature at the flame network surface, and it is visually observed that a blue flame is generated from the flame network in the combustion device. In addition to being able to confirm, it is necessary to confirm that there is a flame by the flame detector provided in the fan heater. This is because, when the flame of the fan heater can be visually recognized as blue, it can be determined that the fan heater is operating normally. If the blue flame is not clearly visible due to the flame becoming inconspicuous, visually check for problems peculiar to the fan heater, such as incomplete combustion of the fuel due to insufficient oxygen, or clogging of the flame holes in the burner head. It is because it can be judged by. Further, even if the flame of the fan heater is generated in such a small amount that it cannot be detected by the flame detector, a problem specific to the fan heater can be determined in the same manner.

  Conventionally, as an invention related to a combustion burner, Patent Document 1 discloses a “forced vaporization combustion apparatus capable of burning unburned gas in a combustion burner that causes an unpleasant odor during fire extinguishing and suppressing the generation of an unpleasant odor. For the purpose of providing a combustion burner (paragraph No. 0008 of Patent Document 1), "... in a combustion burner of a forced vaporization combustion apparatus, the unburned gas remaining in the mixing chamber when the flame network is extinguished. A combustion burner of a forced vaporization combustion apparatus characterized in that it is formed of a metal net carrying a catalyst that oxidizes the catalyst is disclosed (see claim 1 of Patent Document 1).

  The catalyst supported on the metal net in this “combustion burner” is platinum palladium (paragraph number 0015 of Patent Document 1). According to the combustion burner provided with a metal net having a catalyst carrying platinum palladium, “the unburned gas generated immediately after extinguishing the fire is brought into contact with the catalyst raised to an active temperature by the combustion flame F and oxidized. In other words, this does not produce an intermediate product of aldehydes, which is the cause of the generation of off-flavor with irritation "(paragraph number 0019 of Patent Document 1).

  The invention described in Patent Document 1 realizes reducing the amount of aldehydes generated in a combustion burner using kerosene as fuel. Patent Document 1 does not disclose any catalyst other than platinum palladium as a catalyst.

  Patent Document 2 discloses a “burning burner characterized in that a combustion burner carrying a catalyst for oxidizing the unburned gas to the burner net of the burner and the back net is provided with a firing step on the back net”. (Claim 1 of Patent Document 2).

  Patent Document 2 discloses "platinum palladium" as a catalyst for oxidizing unburned gas (paragraph numbers 0007 and 0016 of Patent Document 2).

  The invention described in Patent Document 2 states that “combustion is stopped, but a very small amount of unburned gas remains in the combustion burner 1, and the unburned gas contacts the flame outlet network 6 at about 500 to 600 ° C. Then, an intermediate product of aldehydes is produced, and a strange odor accompanied by irritation is generated (paragraph number 0007 of Patent Document 2), which has a technical effect (paragraph number of Patent Document 2). 0031).

  Therefore, like the invention described in Patent Document 1, the invention described in Patent Document 2 does not disclose anything about preventing the generation of odor of unburned kerosene accompanying the stoppage of kerosene combustion.

The invention described in Patent Document 3 uses “a decomposition and removal apparatus that decomposes and removes volatile organic compounds (VOC) contained in exhaust gas by using ceria (CeO ₂ ) as a catalyst and the decomposition and removal apparatus thereof. Decomposing and removing volatile organic compounds such as aliphatic hydrocarbons such as hexane, aromatic hydrocarbons such as benzene and toluene, aromatic hydrocarbons such as naphthalene, etc. The present invention relates to an apparatus and a decomposition / removal method using the decomposition / removal apparatus "(paragraph number 0001 of Patent Document 3).

  Moreover, patent document 3 is disclosing the detailed examination result about the decomposition reaction of benzene and toluene.

The invention described in Patent Document 4 “provides a catalyst suitable for catalytic reduction of nitrogen oxides in exhaust gas using NH ₃ , particularly in a high temperature region where the exhaust gas temperature is 400 ° C. to 600 ° C.” In order to achieve the above-mentioned object (Patent Document 4, page 2, column 1, lines 32 to 35), the activated alumina carries an oxide having an enthalpy of formation of oxide of -ΔHf ⁰ ≧ 80. An object removal catalyst (see claim 1 of Patent Document 4) is disclosed. CeO ₂ is disclosed as the active ingredient (Patent Document 4, page 2, column 2, line 12). The catalyst disclosed in Patent Document 4 is specifically used as a catalyst for removing nitrogen oxides from a gas composed of nitrogen oxide, ammonia, oxygen, water and nitrogen (see page 3, page 3, page 4 of Patent Document 4). Column 40th line to page 4, column 5, second line). Although ammonia is useful as a reducing agent for nitrogen oxides, it is dangerous to use indoors because it has an irritating odor and is toxic. Furthermore, a dedicated tank is required for storage of ammonia, and it is necessary to add it whenever it is consumed.

The invention described in Patent Document 5 relates to “a catalyst for purifying exhaust gas that reduces nitrogen oxides contained in the exhaust gas of an automobile engine and a method for producing the same” (paragraph number 0001 in Patent Document 5). In addition, by supplying a reducing agent such as light oil, an object of providing a “catalyst for exhaust gas purification that can stably and highly efficiently reduce NOx contained in exhaust gas” (paragraph No. 0004 in Patent Document 5) is provided. In order to achieve this, the “exhaust gas purifying catalyst composed only of CeO ₂ ” (Claim 1 of Patent Document 5) is used as means. In the exhaust gas purifying catalyst described in Patent Document 5, the NOx removal rate and the conversion rate to N ₂ O are investigated for the simulated gas having a specific composition simulated in the exhaust gas of a diesel engine (paragraph number in Patent Document 5). Column 0013). In this Patent Document 5, there is no description or suggestion that the catalyst described in this Patent Document 5 can be diverted to a fan heater.

Furthermore, the invention described in Patent Document 6 is to “reducing HC (hydrocarbon) and NOx, which are the source of odor when a combustion apparatus such as an oil fan heater is extinguished” (paragraph number of Patent Document 6). 0001). The “combustion device” according to Patent Document 6 is “..., and the outer wall of the burner head is provided with a metal mesh-like outer net in close contact with the wall surface, and this outer net carries a noble metal catalyst and is low. The catalytic combustion is performed at an air ratio, and a burner head ring provided with... Is provided (Claim 1 of Patent Document 6). As described above, according to the present invention, the noble metal catalyst supported on the outer net of the burner head causes catalytic combustion in the outer net portion, the outer net is in a red hot state at the time of stable combustion, and the combustion fan is driven immediately after extinguishing the fire. By pushing the unburned gas in the vaporization cylinder into contact with the outer net that is sufficiently red hot by the catalyst, it can be burned almost completely, and when released into the room, it is almost converted into CO ₂ and H ₂ O. The odor is converted to 1 / Is intended to reduce the degree. Is described as ". Further, paragraph No. 0007 of Patent Document 6 states that “Furthermore, catalytic combustion in the outer net is partial combustion at a low air-fuel ratio and the reaction temperature is low, and secondary air is supplied in the burner head ring after passing through the outer net. In other words, it is possible to provide an environmentally friendly combustion device by generating NOx by combustion at a low combustion temperature by the two-stage combustion that undergoes complete combustion in response to the combustion. "

  In Patent Document 6, “platinum, palladium, and the like” is listed as a specific example of the noble metal catalyst (paragraph number 0011). Further, according to Patent Document 6, it is "solved by reducing the odor reduction during fire extinguishing by supporting the noble metal catalyst 12 on the outer net 10" (paragraph number 0025 of Patent Document 6).

  However, according to the study by the present inventors, when only platinum or palladium is supported on a flame hole network of a fan heater such as an oil fan heater or a gas fan heater, catalytic combustion is intense and the flame network becomes red hot. Therefore, the blue flame is not confirmed in the heater during operation, and the user is likely to misunderstand that the fan heater is out of order.

  For the fan heater, the flame formed by the flame holes must always be kept blue, the generation of NOx must be suppressed as much as possible during the operation of the fan heater, and the fan heater operation is stopped. However, there was a particular realization problem that no fuel odor was generated.

JP 10-23003 A JP 2000-35202 A JP2007-175612 JP 05-329332 A JP 08-290057 JP2012-220135

  The present invention provides a fan heater catalyst that can solve such problems and can realize a realization problem peculiar to the fan heater, and such a fan heater catalyst. It is an object of the present invention to provide a fan heater that realizes confirmation of the combustion state and suppresses the generation of NOx as much as possible and does not generate a fuel odor even after the operation of the fan heater is stopped.

The first means for solving the previous problem of this invention is:
(1) A fan heater catalyst characterized by containing cerium oxide,
(2) The fan heater catalyst according to claim 1, wherein the catalyst is supported on at least one inorganic oxide selected from the group consisting of alumina, titania, lanthanum oxide, zirconia, or silica,
(3) The fan heater catalyst according to claim 2, wherein a mass ratio of the inorganic oxide to the cerium oxide is 100: 0.1 to 100: 18.
(4) The catalyst for a fan heater according to claim 1, wherein the catalyst contains at most 0.25% by mass of platinum or at most 0.01% by mass of palladium with respect to the total amount of the catalyst. And
(5) A fan heater having a combustion device comprising a burner head having a flame hole on a side surface, and a flame hole network disposed on the burner head so as to cover the flame hole,
A fan heater, wherein the fan heater catalyst according to any one of claims 1 to 4 is fixed to a surface of the flame hole network.

  According to the present invention, technical problems peculiar to the fan heater can be solved at once, that is, generation of fuel odor after the fan heater is stopped is suppressed, and NOx is generated during operation of the fan heater. By having a catalyst for a fan heater that can be suppressed and confirming a good combustion state, and having such a catalyst for a fan heater, it is possible to confirm a good combustion state during operation of the fan heater and NOx The fan heater which suppresses generation | occurrence | production of this as much as possible and does not generate | occur | produce a fuel odor at the time of a fan heater's operation stop can be provided.

FIG. 1 is a cross-sectional view of a fan heater combustion apparatus.

  As shown in FIG. 1, a combustion apparatus 1 included in a fan heater that is an example of the present invention includes a bottomed cylindrical vaporization cylinder 3 having an opening 2 and a fuel supply pipe that feeds fuel into the vaporization cylinder 3. 4, a blower pipe 5 for sending air to the inside of the vaporizing cylinder 3, a burner head 6 installed so as to cover the opening 2 of the vaporizing cylinder 3, and a through hole provided in the outer peripheral wall of the burner head 6. The combustion apparatus includes a flame hole 7 and a flame hole network 8 disposed on the burner head 6 so as to cover the flame hole 7 and to which a catalyst containing cerium oxide is fixed.

  The vaporizing cylinder 3 is a bottomed cylindrical body having an opening 2 in the upper part, and can have various shapes as long as fuel can be vaporized therein. Examples of the shape of the vaporizing tube 3 include a bottomed cylindrical shape and a bottomed rectangular tube shape. The shape and size of the vaporizing cylinder 3 can be appropriately changed in design according to the size of the heater provided with this combustion device, the situation of use, and the like.

  As the material of the vaporizing cylinder 3, various materials can be adopted as long as it has heat resistance and has an appropriate strength under the usage condition of the fan heater, and usually a metal can be used.

  The fuel supply pipe 4 is connected to the lower peripheral wall of the vaporization cylinder 3. Inside the fuel supply pipe 4, a pump such as an electromagnetic drive pump installed upstream of the fuel supply pipe 4 supplies fuel to the vaporization cylinder 3. Pump inside. At the tip of the fuel supply pipe 4 disposed inside the vaporizing cylinder 3, a spray nozzle 4A for atomizing the fuel is installed.

  As the material of the fuel supply pipe 4, various materials can be adopted as long as it has heat resistance and appropriate strength, and is usually made of copper.

  The length, the inner diameter, and the shape of the fuel supply pipe 4 in the axial direction are not particularly limited as long as an appropriate amount of fuel can be supplied to the vaporizing cylinder.

  The blower pipe 5 is connected to the lower peripheral wall of the vaporizing cylinder 3. Inside the blower pipe 5, a blower or the like installed upstream of the pipe feeds air into the vaporizing cylinder 3.

  The air sent to the inside of the vaporizing cylinder 3 serves as an oxygen supply source for burning the fuel, and also functions to atomize the fuel together with the fuel sent by the fuel supply pipe 4 inside the vaporizing cylinder 3 Have In order to atomize the fuel, it is preferable that the fuel supply pipe 4 and the blower pipe 5 are located close to each other on the lower peripheral wall of the vaporization cylinder 3 so that the air can atomize the fuel. As a more preferable mode of the blower pipe 5 and the fuel supply pipe 4, as shown in FIG. 1, the outlet of the fuel supply pipe 4 is arranged inside the blower pipe 5 and at the tip outlet of the blower pipe 5. The blower pipe 5 and the fuel supply pipe 4 form a double pipe structure.

  Various materials can be adopted as the material of the blower tube 5 as long as it has heat resistance and appropriate strength, and is usually made of metal.

  The axial length, the inner diameter, and the shape of the blow pipe 5 are not particularly limited as long as an appropriate amount of air can be supplied to the vaporizing cylinder and the fuel can be atomized inside the vaporizing cylinder 3.

  A vaporizing heater 9 is installed outside the bottom of the vaporizing cylinder 3. As the vaporizing heater 9, a sheathed heater that uses Joule heat by the action of electric current can be suitably used. The temperature inside the vaporizing cylinder 3 is sensed by the thermistor 10 installed on the lower peripheral wall of the vaporizing cylinder 3, and is maintained at 220 ° C. to 250 ° C. by energization control during operation of the fan heater. During the operation of the fan heater, the fuel atomized in the lower part of the vaporizing cylinder 3 is gasified by the heat generated by the vaporizing heater, and is preliminarily mixed with the air supplied by the blower pipe 5, so that the mixed gas is vaporized. Ascend the inside of 3.

  A flame adjusting cylinder 11 is attached between the vaporizing cylinder 3 and the burner head 6. The flame adjusting cylinder 11 is formed in a circular plate-like body 11A designed to cover the opening 2 of the vaporizing cylinder 3, and protrudes into the vaporizing cylinder 3 at the center of the plate-like body 11A. A cylindrical body 11B is formed, and the vaporizing cylinder 3 and the burner head 6 communicate with each other through the cylindrical body 11B. The flame adjusting cylinder 11 formed in this way can guide the mixed gas to the flame hole 7 of the burner head 6 while rectifying the mixed gas rising inside the vaporizing cylinder.

  The burner head 6 is installed so as to cover the upper opening of the vaporizing cylinder 3 and to sandwich the flame adjusting cylinder 11 with the vaporizing cylinder 3. The burner head 6 has a semicircular shape or a cylindrical shape. In addition, when the top and bottom of the burner head is reversed, it can be described as “presenting a bottomed cylindrical shape with one end corresponding to the bottom surface open”. The shape and size of the burner head 6 can be appropriately changed according to the shape of the vaporizing cylinder 3.

  As the material of the burner head 6, various materials can be adopted as long as the material has heat resistance and appropriate strength, and is usually made of metal.

  The flame holes 7 are provided on the peripheral wall of the burner head 6 in a single row or a matrix. During operation of the fan heater, the fuel that has risen from the inside of the vaporizing cylinder 3, for example, a mixed gas of kerosene and air, is sent out from the inside of the burner head 6 through the flame hole 7. The mixed gas sent out from the flame hole 7 burns, and a flame portion 12 is formed toward the outside of the burner head.

  The inner diameter and the number of the flame holes 7 are appropriately determined so that an appropriate amount of mixed gas can be supplied for the combustion apparatus of the heater to stably burn. In particular, the upper and lower flame holes are 6 to 7 mm in diameter on the peripheral wall of the burner head 6, the lower flame hole is 5 to 5.5 mm in diameter, and 16 flame holes per stage on the peripheral wall. 7 is preferably arranged.

  The flame hole network 8 is attached in the vicinity of the peripheral wall of the burner head 6 so as to cover the flame hole 7. The flame network 8 is made of a heat-resistant material, and can be made of metal in particular. Stainless steel is preferred as the metal forming the flame hole network 8 in that it has excellent heat resistance and high strength. As the shape of the flame hole network 8, a shape that increases the contact area with the mixed gas and does not significantly disturb the flow of the mixed gas is good, and has a mesh structure having a size of about 0.1 to 10 mm. Is preferred.

A catalyst containing cerium oxide (CeO ₂ and Ce ₂ O ₃ ) is fixed to the surface of the flame network 8. The mode in which the catalyst is fixed to the surface of the flame network 8 is such that the catalyst itself not supported on the support is fixed to the flame network and the mode in which the catalyst supported on the support is fixed to the flame network. Either may be sufficient.

  The cerium oxide contained in the catalyst fixed to the surface of the flame hole 8 is usually in the form of fine particles. The particle diameter of the catalyst in the form of fine particles is preferably 5 to 100 nm.

A suitable fixed amount of cerium oxide contained in the catalyst fixed to the flame network 8 is usually in the range of 0.01 to 0.75 mg / cm ² . Even if the mass of cerium oxide contained in the catalyst fixed to the flame hole network 8 exceeds 0.75 mg / cm ² , the technical effect corresponding to the increased amount of the catalyst may not be achieved.

  The catalyst fixed to the flame network 8 can be supported on an inorganic oxide. The inorganic oxide functions as a carrier, a bulk material, and a binder, improves the dispersibility of cerium oxide, suppresses sintering over time, and assists immobilization in the flame network. As the inorganic oxide, a substance that does not inhibit the catalytic activity of cerium oxide and noble metal, is chemically stable, and can increase the surface area of cerium oxide and noble metal can be employed. Specific examples of the inorganic oxide include at least one inorganic oxide selected from the group consisting of alumina, titania, lanthanum oxide, zirconia, and silica. A more preferred inorganic oxide is alumina. The preferred particle size of the inorganic oxide is usually 10 nm to 100 nm. The mass ratio of cerium oxide in the catalyst fixed to the flame network 8 to the inorganic oxide supporting the catalyst is in the range of inorganic oxide: cerium oxide = 100: 0.1 to 100: 18. preferable.

  The catalyst fixed to the flame hole network 8 preferably has a large surface area by forming pores in order to increase the contact frequency with the combustion gas. As a method of increasing the surface area of the catalyst, when preparing the catalyst, a nanocarbon material is further added to the catalyst or the catalyst and the support to mix the catalyst and the nanocarbon material, or the catalyst, the support and the nanocarbon material are mixed uniformly. Then, pores can be formed in the catalyst by firing and removing the nanocarbon material. Examples of the nanocarbon material include single-walled carbon nanotube (SWCNT), double-walled carbon nanotube (DWCNT), multi-walled carbon nanotube (MWCNT), carbon nanofiber (CNF), carbon nanohorn, and fullerene. From the viewpoint of facilitating the flow of the combustion gas to the inside, a more preferable nanocarbon material is a multi-walled carbon nanotube. Preferred carbon nanotubes have a diameter of 10 nm or more and a length of 100 nm to 10 μm.

  The catalyst 16 may contain a noble metal other than cerium oxide as long as the object of the present invention is achieved. Examples of noble metals other than cerium oxide include platinum and palladium. The content of these noble metals in the catalyst is at most 0.25% of the mass ratio of platinum and 0.01% at most of the mass ratio of palladium with respect to the total mass of the inorganic oxide and the catalyst. It is. More preferably, the mass ratio of platinum to the total mass of the inorganic oxide and the catalyst is at most 0.15%, and the mass ratio of palladium is at most 0.005%. A noble metal such as platinum and / or palladium acts as a combustion catalyst in the same manner as cerium oxide. However, if the mass ratio of the noble metal to the total mass of the catalyst exceeds the above value, the amount of reaction on the surface of the network increases and the amount of combustion increases. Increased, the net becomes intensely red hot. At this time, the temperature of the mesh surface may exceed 1000 ° C., which causes a problem in catalyst deterioration and durability of the mesh itself. Further, the blue flame that should be formed outside the flame hole network 8 becomes small, and it is judged that the operation state of the fan heater is bad, and there is a possibility that the object of the present invention cannot be achieved. A catalyst containing a noble metal other than cerium oxide and having a large surface area is formed, for example, by placing the noble metal on the nanocarbon material and then firing and removing the nanocarbon material to place the noble metal in the resulting pores. And a catalyst that can increase the frequency of contact with the combustion gas is formed.

  In order to fix the catalyst to the flame network, first, the cerium oxide, the inorganic oxide, the binder and water are mixed, suspended or dispersed, and the resulting suspension or dispersion is used as the coating liquid. To do.

  Suitable binders include inorganic oxide sols such as alumina sol, titania sol, and silica sol, and aluminum hydroxide powder. The amount of the binder is preferably added so as to be 2 to 20% by mass based on the solid content when the catalyst is formed. The binder becomes a carrier by firing.

  The concentration of the solid content contained in the coating solution is, that is, the total concentration of the cerium oxide, the noble metal, the inorganic oxide, and the solid content contained in the binder is 5 to 20% by mass with respect to the coating solution. It is preferable to prepare. If the solid content is lower than 5% by mass, it may be inefficient because it is necessary to apply the flame network repeatedly with the coating liquid, and if it exceeds 20% by weight, the viscosity of the coating liquid becomes too high. The coating operability of the coating liquid may be deteriorated.

As a method for coating the coating liquid on the flame hole network, any method may be used as long as it is a usual method, and examples thereof include a dip method, a roller method, a brush coating method, a spray method, and a spin coating method. It is done. The thickness of the coating is preferably 1 to 100 μm. Moreover, as for the coating amount of the coating liquid to a flame opening | mouth net | network, 1-20 mg / cm < ² > is preferable as mass per unit area.

  The fan heater according to the present invention includes a spark plug as in the conventional fan heater. As shown in FIG. 1, the spark plug 13 can generate a spark by the discharge between the electrodes. When the fan heater is operated, the spark generated by the spark plug 13 ignites the mixed gas of the fuel and the air that has risen inside the vaporizing cylinder 3, thereby forming a flame on the outside of the burner head 6. The The position and number of the spark plugs 13 can be appropriately changed as long as the flame holes can be ignited.

  The fan heater according to the present invention includes a flame detector as in the conventional fan heater. As shown in FIG. 1, the flame detector 14 detects the combustion state of the combustion device based on a flame voltage using a rectifying action of flame. Usually, the flame detector 14 is composed of an electrode part and a support part, and the electrode part comes into contact with the flame part 12 to detect the flame and functions as a safety device that shuts off the gas when the flame disappears.

  The fan heater according to the present invention includes a burner head ring as in the conventional fan heater. As shown in FIG. 1, the burner head ring 15 absorbs a part of the flame portion 12 and transfers this heat to the vaporizing cylinder 3 in order to achieve the purpose of heating back the heat to the vaporizing cylinder 3. It has a function. As the material of the burner head ring 15, various materials can be adopted as long as they have high temperature durability, and preferably austenitic stainless steel. Thereby, the heater 9 for vaporization is energized only at the time of ignition, and vaporizes kerosene using a part of heat of the flame during combustion, thereby reducing power consumption and saving energy.

  Next, the operation of the fan heater of the present invention will be described.

  For example, when the fan heater having the combustion device 1 is driven, the vaporization heater 9 is energized. After the bottom surface of the vaporizing cylinder 3 reaches a predetermined temperature, kerosene is supplied by the fuel supply pipe 4 and entangled with the air supplied by the blower pipe 5, whereby the kerosene is atomized and atomized. The atomized kerosene that has reached the bottom surface of the vaporizing cylinder 3 is vaporized, and a mixed gas with air becomes an ascending current, reaches the burner head 6 through the cylindrical body 11B, and is ejected to the outside through the flame hole 7. The spark plug 13 ignites the mixed gas ejected from the flame hole 7 to form the flame portion 12. The flame hole network 8 is heated by the flame part 12.

  Since the catalyst containing cerium oxide is fixed to the flame network 8, the mixed gas partially burns on the surface of the flame network 8 due to the catalytic action. It tends to stick to the flame network 8. As a result, the combustion heat of the flame part 12 is taken to the flame hole network 8, the maximum temperature in the flame part 12 can be lowered, and the generation of NOx during the heater operation can be reduced. Therefore, even when the fan heater is operated in a sealed space such as a room, the human body is less likely to malfunction and can be used comfortably, and the ventilation frequency can be reduced.

Further, immediately after the operation of the fan heater is stopped, the flame hole network 8 maintains a higher temperature than the flame hole network not coated with the catalyst, so that the catalyst retains its activity and is vaporized immediately after extinguishing the fire. Comes into contact with the catalyst on the flame network and burns completely, and is decomposed into CO ₂ and H ₂ O, so that unburned HC is prevented from being released to the outside of the fan heater. Therefore, immediately after the operation of the fan heater is stopped, the extent to which the user feels a strange odor is extremely small, and the fan heater can be used comfortably.

  Furthermore, since the flame part 12 becomes easy to stick to the flame network 8, the temperature of the flame network 8 rises. However, since the heat on the flame network 8 is transferred to the burner head and the vaporizing cylinder 3 by heat conduction, and is consumed as energy for kerosene evaporation in the vaporizing cylinder 3, the temperature rises without limit. Absent. In addition, since the action is gentle compared to the case of using platinum and / or palladium as a catalyst, the combustion reaction on the surface of the flame network 8 is relatively small, and the flame network 8 does not become red hot. As a result, the temperature of the flame hole network 8 does not become so high, it is difficult to cause catalyst deterioration and thermal destruction of the flame hole network 8 itself, and durability can be maintained while maintaining performance. Further, it is visually recognized by the user that the flame portion 12 is always a blue flame, and it is confirmed that there is a flame in the flame detector 14, and apparently changes to its combustion state as compared with the case where no catalyst is used. Therefore, the user can surely confirm that the combustion state is good, and unnecessary stress is not given to the user.

Therefore, according to the fan heater of the present invention, it is possible to suppress the amount of HC gas discharged immediately after operation stop and the amount of NOx gas generated during operation, and confirm whether the combustion state during operation of the fan heater is good. it can.
Although an example of the present invention has been described above, the fan heater according to the present invention may be a fan heater that uses liquid fuel such as kerosene and gas fuel, for example.

  Hereinafter, the present invention will be described in more detail with reference to examples. However, the present invention is not limited to these examples.

Example 1
(Preparation of coating solution)
In a 250 ml plastic bottle, γ-alumina (MI386, Rhodia, average particle size 22 μm, specific surface area 182 m ² / g) 16.00 g, cerium oxide (manufactured by TECNAN, average particle size: 10 nm, specific surface area: 121 m ² / g) ) 1.5 g, 10% alumina sol (Kawaken Fine Chemical Co., Ltd., Aluminum Sol 10A) 20.00 g, acetic acid (Kanto Chemical Co., Ltd.) 1.5 g, and 127 g of distilled water were poured for suspension and dispersion. 40.00 g of a zirconia ball having a diameter of 1.5 mm was cast on the plate, and a coating solution was prepared using a rocking mill (50 Hz, 1 hr).

(Catalyst fixation)
A coating solution prepared so that the total fixed amount is 4 mg / cm ² is applied to a stainless mesh (a knitted Kantal (registered trademark) material FeCrAl alloy in a mesh shape) as a flame hole network heat-treated at 950 ° C. Drying (200 ° C., 1 hour), followed by firing (400 ° C., 1 hour) is repeatedly wash-coated until the desired total fixed amount is reached, and finally firing at 800 ° C. for 2 hours. The catalyst was fixed to the stainless steel mesh.

(Fan heater operation, gas measurement)
The stainless steel mesh with the catalyst fixed was attached to the burner head of the exhaust heater fan heater as a flame hole network, and the fan heater was operated. We confirmed stable combustion with a flame detector, observed whether the stainless mesh with the catalyst fixed during stable combustion was red-hot, and observed the flame part of the combustion device during stable combustion. Furthermore, the amount of nitrogen oxide gas (NOx) during stable combustion was measured. The amount of nitrogen oxide gas (NOx) was measured by introducing the exhaust gas in front of the heater body to a NOx meter (multi-gas analyzer VS-3000 manufactured by HORIBA), which is a measuring device, using a dedicated suction pipe. Also, the exhaust gas immediately after the fan heater is stopped, the amount of hydrocarbon (HC) is installed, and a duct for collecting gas is installed on the back of the heater body. Measured by introducing up to.

  Further, a stainless steel mesh that does not fix the catalyst was installed to operate the fan heater, and the NOx amount and HC amount were measured in the same manner.

(Data evaluation)
Compare the gas generation amount of HC and NOx when operating a fan heater with a stainless mesh without a catalyst fixed as a flame hole network, and the gas generation amount of HC and NOx when the catalyst is fixed to a stainless mesh, The reduction rate when using the catalyst was calculated. Moreover, the combustion state at the time of stable combustion was confirmed. As a judgment of the combustion state, if the red heat on the surface of the flame hole network is suppressed, a blue fire can be confirmed visually, and a flame detector can confirm that there is a flame, otherwise it is good The case of was considered defective. The results are shown in Table 3.

(Examples 2 to 5)
A stainless steel mesh having a catalyst fixed thereon was prepared in the same manner as in Example 1 except that the composition of the coating liquid, the type of reagent, and the amount of catalyst fixed to the stainless steel mesh were as shown in Tables 1 and 2. The flame state was recorded, and the exhaust gas was measured. The results of the data evaluation are shown in Table 3.

In addition, γ-alumina in Example 5 is TM-300 (γ-Al ₂ O ₃ , purity 99.99%, specific surface area: 238 m ² / g, average particle size: 10 nm) manufactured by Daimei Chemical Co., Ltd. It was used.

CNT was synthesized by reacting a Ni—MgO catalyst precursor installed in a reaction tube with CH ₄ at a temperature of 500 ° C. for 30 minutes under a condition of 2000 ml / h. (Method described in Carbon Vol.35No.10-11, pp1495-1501)
(Example 6)
(Synthesis of 0.5% Pt / CNT)
20 g of CNT powder, 250 g of distilled water, 0.63 g of sodium carbonate, and 1.02 g of chloroplatinic acid (platinum content: 11.3 wt%) were placed in a 500 ml four-necked flask and stirred. Thereafter, aging was performed at 90 ° C. and the mixture was allowed to cool. Subsequently, in order to reduce platinum, an excess amount of an aqueous solution of sodium borohydride was added with stirring, aged at 90 ° C. and allowed to cool. This suspension was filtered, sufficiently washed with water and dried to obtain 0.5% Pt / CNT.
A coating solution was prepared in the same manner as in Examples 2 to 5, except that the CNT added to the coating solution was changed to Pt / CNT. In the same manner as in Example 1, a stainless mesh having a catalyst fixed thereon was prepared and used as a flame hole network, and the combustion state was recorded and the exhaust gas was measured. The results of the data evaluation are shown in Table 3.
(Comparative Examples 1 and 2)
A noble metal / CNT was prepared in the same manner as in Example 6 except that the noble metal chloride salt was added so that the amount of the noble metal was as shown in Table 1, and a coating solution was prepared. In the same manner as in Example 1, a stainless mesh having a catalyst fixed thereon was prepared and used as a flame hole network, and the combustion state was recorded and the exhaust gas was measured. The results of the data evaluation are shown in Table 3.

  The composition of the coating solution used in the examples and comparative examples is shown in Table 1 below.

※１ γ―アルミナは、大明化学工業（株）社製 ＴＭ−３００である。

* 1 γ-alumina is TM-300 manufactured by Daimei Chemical Co., Ltd.

  The amount of catalyst fixed to the stainless steel mesh in Examples and Comparative Examples is shown in Table 2 below.

  Table 3 below shows the results of the reduction rate compared with HC and NOx measured only with the stainless mesh and the state of the flame on the flame hole network.

  In the examples (Comparative Example 1 and Comparative Example 2) in which only Pt and Pd, which are widely used as combustion catalysts, are used as the catalyst, the generation amount of both HC gas and NOx gas is suppressed as compared with the case where no catalyst is used. However, red heat was generated in the part where the catalyst was applied, and a blue fire was hardly confirmed, and the combustion state was poor. On the other hand, in the examples using the catalyst containing cerium oxide (Examples 1 to 6), in addition to being able to suppress the generation amount of both HC gas and NOx gas, the combustion state was good.

1: Combustion device 2: Opening portion 3: Vaporization cylinder 4: Fuel supply pipe 4A: Spray nozzle 5: Blower pipe 6: Burner head 7: Flame hole 8: Flame hole network 9: Heating heater 10: Thermistor 11: Flame control Tube 11A: Plate body 11B: Cylindrical body 12: Flame part 13: Spark plug 14: Flame detector 15: Burner head ring

Claims (5)

  A fan heater catalyst comprising cerium oxide.   2. The fan heater catalyst according to claim 1, wherein the catalyst is supported on at least one inorganic oxide selected from the group consisting of alumina, titania, lanthanum oxide, zirconia, and silica.   The fan heater catalyst according to claim 2, wherein a mass ratio of the inorganic oxide to the cerium oxide is 100: 0.1 to 100: 18.   2. The fan heater catalyst according to claim 1, wherein the catalyst contains at most 0.25% by mass of platinum or at most 0.01% by mass of palladium based on the total amount of the catalyst. A fan heater having a combustion device comprising a burner head having a flame hole on a side surface and a flame hole network disposed on the burner head so as to cover the flame hole,
A fan heater, wherein the fan heater catalyst according to any one of claims 1 to 4 is fixed to a surface of the flame hole network.

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