JPH0136001B2 - - Google Patents

Description

[Detailed Description of the Invention] Industrial Application Field The present invention relates to a vaporizing liquid fuel combustion device that is widely used in heaters, cookers, etc., and particularly relates to a vaporizing chamber that causes problems when tar accumulates. It is.

Structure of the Conventional Example and Its Problems The vaporization chamber of the conventional device was made of metal or a heat-resistant film coated on metal. However, in conventional equipment, tar accumulates on the walls of the vaporization chamber,
There was a problem that white smoke and odor were generated when the fire was ignited and extinguished.

OBJECTS OF THE INVENTION It is an object of the present invention to solve these conventional problems and provide a vaporized liquid fuel combustion device that includes a vaporizing chamber in which less tar accumulates.

In order to achieve the object of the present invention, all or part of the wall of the vaporization chamber is made of a highly thermally conductive and highly radiation material in an amount of 15 to 50% by weight, an organic substance decomposition catalyst in an amount of 0.1 to 15% by weight, and a heat resistant material. By coating with an organic decomposition film consisting of 40 to 80% binder, emissivity of 0.8 or higher, thermal conductivity of 4Kcal/mh℃ or higher, and film thickness of 30 microns or lower, and maintaining the vaporizing surface temperature at 350℃ or higher, It reduces tar accumulation through the thermal effects of heat transfer and radiation as well as catalytic effects.

DESCRIPTION OF THE EMBODIMENTS One main component of the vaporization chamber wall coating of the present invention is a fine powder material with high thermal conductivity and high radiation,
Contains 15 to 50% by weight of at least one selected from the group of carbon, graphite, beryllium oxide, magnesium oxide, silicon carbide, vanadium carbide, tungsten carbide, titanium carbide, boron nitride, and zirconium boride. is necessary.

The second main component is an organic matter decomposition catalyst,
Oxides of titanium, zirconium, vanadium, chromium, molybdenum, tungsten, manganese, iron, cobalt, nickel, copper, and rare earths, elemental platinum and palladium, activated clay, zeolites, calcium silicate, alumina cement, potassium carbonate. At least one species selected from the group
It is necessary to contain 0.1 to 15% by weight. Furthermore, the third main component is a heat-resistant binder, which must contain 40 to 80% by weight of a material selected from the group of water-soluble phosphates, water-soluble silicates, and silicone paints.

FIG. 1 shows the principle of the apparatus of the present invention, in which liquid fuel 1 is ejected together with air 2, vaporized on a heating vaporization surface 3, and the mixed gas is combusted in a burner head 4 to form a flame 5.

6 is a metal vaporizing cylinder made of iron, aluminum, stainless steel, aluminized steel plate, etc.;
8 is an electric heater for heating the vaporization cylinder, and 8 is a temperature detection element. The temperature of the vaporization surface 3 is detected by the detection element 8, and at the start of combustion, the temperature is detected by the electric heater 7.
During steady combustion, conductive heat from the burner head 4,
The film boiling temperature is maintained by recovering exhaust heat from the combustion exhaust gas. During steady combustion, the electric heater 7 acts as an auxiliary heat source.

Figure 2 is a partial enlarged view of the vaporization chamber, and the film 3 is made up of a highly thermally conductive and highly radiation material 9 (indicated by x), an organic decomposition catalyst 10 (indicated by Γ), and a heat-resistant binder 10 (indicated by diagonal lines). Consisting of

When using a device with such a vaporization chamber to maintain the vaporization surface temperature at the film boiling temperature and vaporize a vicious liquid fuel 1 that contains a large amount of non-volatile components 12 (indicated by △) that cause tar, high heat is generated in the film. When the conductive and highly emissive material 9 is present, the volatile components in the fuel are vaporized in a very short time due to the thermal effects of heat transfer and radiation, and the residence time on the film is shortened, resulting in less tar. Furthermore, when the thermal conductivity of the film increases, the liquid fuel undergoes film boiling, becomes spherical, and evaporates while moving on the film, increasing the area where non-volatile components accumulate. This reduces the load on the organic matter decomposition catalyst that has the action of decomposing non-volatile components, thereby reducing tar production.

If a material with high thermal conductivity but low emissivity, such as aluminum, is present in the film, the liquid fuel will undergo film boiling, but the vaporization time will be prolonged, causing recombination and coarsening of the fuel, which will adversely affect combustion. do not have.

Organic matter decomposition catalysts reduce tar production by oxidative decomposition, partial oxidative decomposition, or cracking of nonvolatile components that cause tar.

The heat-resistant bonding material is a material that has high thermal conductivity and is necessary for bonding the highly radiation material and the organic substance decomposition catalyst to the vaporization cylinder.

The main materials are water-soluble phosphate, water-soluble silicate, and silicone-based paints, but hardening materials are used to ensure complete curing and shorten curing time, as well as fire resistance, oil resistance, water resistance, etc. A filler is used to ensure the proper film properties. As for the film composition, the higher the content of high thermal conductivity and high radiation material and organic decomposition catalyst, the lower the content of heat-resistant binder, the less the amount of tar generated, but the better the adhesion with the vaporizing cylinder.
Addition of 40-90% by weight of heat-resistant binder is necessary to ensure film reinforcement.

This will be explained below using a specific example.

First, a conventional example will be explained.

(1) Regarding devices coated with a conventional heat-resistant film, a silicon-based heat-resistant binder containing ferrite is used as a filler. Its structure is the first
Similar to the one shown in the figure, the above-mentioned heat-resistant film was coated to a thickness of 30 μm on the wall of the vaporization chamber, which was made of an aluminized steel plate with a thickness of 1.6 mm and had an inner diameter of 40 mm and a height of 30 mm. The film in this example has an emissivity of 0.80 and a thermal conductivity of approximately 0.8 Kcal/m at 200°C.
It is h℃.

In this device, the temperature of the vaporizer cylinder is set to 350℃ using a heater and combustion heat, and 2.8 liters of bad kerosene containing 37.5 ppm of non-volatile components that cause tar are heated.
Spray and vaporize at a rate of 5.3Nm ³ /Hr, air amount 5.3Nm 3 /Hr,
When the time-dependent change in the amount of accumulated tar was measured during combustion, characteristic line 1 shown in FIG. 3 was obtained. 1000
Approximately 300mg of tar will accumulate in an hour, and it is expected that more than 1g of tar will accumulate in 15,000 hours, resulting in an increase in odor, hydrocarbon, and carbon monoxide emissions during ignition and extinguishing, which is undesirable for a combustor.

Since this conventional coating has low thermal conductivity, kerosene vaporizes by nucleate boiling near the collision surface, causing tar to accumulate there.

Next, an example of the present invention will be described.

(2) After firing, the same vaporizer cylinder as in the example (1) above has a film composition of approximately 30μ thick consisting of 45% by weight of graphite, 10% by weight of manganese dioxide, and 45% by weight of heat-resistant binder.
An organic matter decomposition film was formed.

The heat-resistant bonding material (hereinafter referred to as bonding material) in this example is composed of primary aluminum phosphate as a main material, sodium phosphate as a hardening material, and alumina as a filler.

The radiation rate of this film at 200℃ is 0.90,
Thermal conductivity is approximately 15 Kcal/mh°C.

When the change over time in the amount of accumulated tar was measured under the same conditions as in (1) above, characteristic line 2 was obtained as shown in FIG.

Approximately 4.3mg of tar accumulates in 1000 hours,
Even after 15,000 hours, the amount is expected to be extremely low at approximately 6 mg.

The film in this example has high thermal conductivity, so kerosene is
Film boiling occurred at temperatures above 300°C and vaporization occurred throughout the bottom of the vaporization chamber.

(3) As shown in Figures 4 and 5, in the vertical vaporization chamber, the kerosene collision surface is metal, and the other surfaces are as above.
When the sample was coated with the same film as in example (2) and the time-dependent change in the amount of accumulated tar was measured under the same conditions as in example (1) above, characteristic line 3 as shown in FIG. 3 was obtained.

Approximately 3.2 mg of tar accumulated on the bottom of the vaporization chamber in 1000 hours.

(4) In the same vaporizer cylinder as in the example (1) above, the film composition after firing is 20% by weight of beryllium oxide, 10% by weight of alumina cement as an organic matter decomposition catalyst, and 70% by weight of a binder.
An organic matter decomposition film with a thickness of about 30 μm was formed. The binder in this example is composed of sodium silicate as the main material and silica as the filler. The radiation coefficient of this film at 200℃ is 0.82, and the thermal conductivity is approximately 10Kcal/m
It is h℃. When the change over time in the amount of accumulated tar was measured under the same conditions as in example (1), characteristic line 4 shown in Fig. 3 was obtained. Approximately 12 mg of tar accumulated on the bottom of the vaporization chamber in 1000 hours.

(5) Organic substance decomposition with a thickness of approximately 30 μm on the same vaporizing cylinder as in the example (1) above, with a film composition after firing of 23% by weight of graphite, 76.8% by weight of binder, and 0.2% by weight of platinum as an organic substance decomposition catalyst. A film was formed.

The binder in this example is composed of primary aluminum phosphate as the main material, sodium phosphate as the hardening material, and alumina as the filler. The radiation coefficient of this film at 200°C is 0.81, and the thermal conductivity is approximately 7 Kcal/mh°C.

When the change in accumulated tar over time was measured under the same conditions as in example (1), the characteristic line 5 shown in FIG. 3 was obtained.
Approximately 13 mg of tar accumulated on the bottom of the vaporization chamber in 1000 hours.

(6) An organic matter decomposition film with a thickness of about 30 μm was formed on the same vaporizing cylinder as in Example (1) above, with a film composition after firing of 23% by weight of graphite, 10% by weight of manganese dioxide, and 67% by weight of binder. In this example, the bonding material is primary aluminum phosphate, the hardening material is sodium phosphate, and the filler is alumina. The radiation coefficient of this film at 200℃ is 0.83, and the thermal conductivity is approximately 8Kcal/
mh℃. When the change over time in the amount of accumulated tar was measured under the same conditions as in example (1), characteristic line 6 shown in FIG. 3 was obtained. Approximately 40 mg of tar accumulated on the bottom of the vaporization chamber in 1000 hours.

(7) The same vaporizing cylinder as in the example (1) above has a film composition of 23% by weight of graphite, zeolite [Ca(Na,
K) _An organic matter decomposition film having a thickness of about 30 μm was formed consisting of 8% by weight of 4.Al ₆ Si ₃₀ O ₇₂ ], 2% by weight of activated clay [Al ₂ Si ₁₃ O ₂₉ ], and 67% by weight of a binder.

The binder in this example is composed of primary aluminum phosphate as the main material, sodium phosphate as the hardening material, and alumina as the filler. The radiation coefficient of this film at 200°C is 0.83, and the thermal conductivity is approximately 6 Kcal/mh°C.

The characteristic line 7 shown in FIG. 3 was obtained by measuring the change over time in the amount of accumulated tar under the same conditions as in example (1).
Approximately 52 mg of tar accumulated on the bottom of the vaporization chamber in 1000 hours.

(8) The film composition after firing on the same vaporizing cylinder as in the example (1) above is approximately 20% by weight of boronated zircon, 13% by weight of manganese dioxide, and 67% by weight of binder.
A 30μ thick organic matter decomposition film was formed. The bonding material in this example is composed of silicone resin as the main material and ferrite as the filler. The radiation coefficient of this film at 200℃ is 0.81,
Thermal conductivity is approximately 6 Kcal/mh°C.

When the change over time in the amount of accumulated tar was measured under the same conditions as in example (1), a characteristic line 8 shown in FIG. 3 was obtained. Approximately 110 mg of tar accumulated on the bottom of the vaporization chamber in 1000 hours.

(9) The film composition after firing is 20% by weight of silicon carbide and calcium silicate on the same vaporizing cylinder as in the example (1) above.
An organic matter decomposition film consisting of 10% by weight and 70% by weight of the binder was formed. The binder in this example is made of sodium silicate as the main material and silica as the filler.

The radiation rate of this film at 200℃ is 0.80,
Thermal conductivity is approximately 4Kcal/mh°C.

When the change over time in the amount of accumulated tar was measured under the same conditions as in example (1), a characteristic line 9 shown in FIG. 3 was obtained. Approximately 140 mg of tar accumulated on the bottom of the vaporization chamber in 1000 hours.

Effects of the Invention As described above, according to the present invention, 15 to 50% by weight of a highly thermally conductive and highly radiation material, an organic matter decomposition catalyst,
Composed of 0.1 to 15% by weight and 40 to 80% by weight of heat-resistant binder, radiation rate of 0.8 or more, thermal conductivity of 4Kcal/
By maintaining the temperature of the vaporization surface coated with an organic decomposition film of mh℃ or higher and 30 microns or less in thickness at 350℃ or higher, the amount of tar accumulated is reduced by 30% to 1/10 compared to conventional vaporizers. A type liquid fuel combustion device is obtained.

[Brief explanation of drawings]

1a and 1b are top views and sectional views showing one embodiment of the vaporization type liquid fuel combustion device of the present invention, FIG. 2 is a partially enlarged sectional view of the vaporization chamber in the same device, and FIG.
The figure is a characteristic diagram showing the relationship between the combustion time and the amount of accumulated tar, Figures 4a and 4b are top views and cross-sectional views of other embodiments of the present invention, and Figure 5 is a partially enlarged cross-sectional view of the vaporizing chamber in the same device. It is. 3... Vaporization surface, 7... Electric heater, 8... Temperature detection element.

Claims (1)

[Claims] 1. A material with radiation coefficient of 0.80 or more and thermal conductivity, consisting of 15 to 50% by weight of a material with high thermal conductivity and high radiation, 0.1 to 15% by weight of an organic substance decomposition catalyst, and 40 to 80% by weight of a heat-resistant binder. A vaporizing liquid fuel combustion device configured to maintain the vaporizing surface at 350°C or higher, coated with an organic matter decomposition film with a rate of 4Kcal/mh°C or higher and a film thickness of 30 microns or less. 2. Carbon, graphite, beryllium oxide, magnesium oxide,
silicon carbide, vanadium carbide, tungsten carbide, titanium carbide, boron nitride,
The vaporized liquid fuel combustion device according to claim 1, which contains at least one member selected from the group of zirconium borides. 3. As organic matter decomposition catalysts, titanium, zirconium, vanadium, chromium, molybdenum, tungsten, manganese, iron, cobalt, nickel, copper,
and one or more selected from the group of rare earth oxides, elemental platinum and palladium, activated clay, zeolite, calcium silicate, alumina cement, and potassium carbonate. Combustion device. 4 Water-soluble phosphate paint as a heat-resistant binder,
The vaporized liquid fuel combustion device according to claim 1, which is selected from the group of water-soluble silicate paints and silicone paints. 5. The vaporizing liquid fuel combustion device according to claim 1, wherein the vaporizing chamber temperature is maintained at 350° C. or higher using an electric heater and a temperature detecting element.