JPS6220443B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention evaporates liquid fuel such as kerosene and light oil,
Regarding a liquid fuel combustion device that gasifies and burns the desired air by mixing it with air, the liquid fuel wicking body is made of a non-sintered porous material using silicate lime as a binder, and the liquid fuel is wicked up. By performing vaporization and transpiration and supplying the thus obtained mixed gas to the burner section, a simple and long-term stable liquid fuel combustion device is provided. The main types of conventional heated kerosene gasifiers are broadly divided into stationary types and rotary types, but in principle both use electric heat to heat a heat medium with a relatively large heat capacity to the boiling point of kerosene. In comparison, the heating medium is maintained at a sufficiently high temperature to vaporize the kerosene on the surface of the heating medium. In addition, in recent years, porous bodies such as ceramic sintered bodies have been used to construct liquid fuel wicking bodies, and kerosene is sucked up by this wicking body and vaporized in its vaporization section.
Products that mix this with air and burn it have been commercialized and are attracting attention, but these conventional products produce unburned products such as soft carbon, hard carbon, and tar in the vaporization part. As a result, combustion was adversely affected. The present invention relates to a device that sucks up and vaporizes liquid fuel, and in order to solve the above-mentioned conventional problems, the present invention uses lime silicate, which is alkaline and can be composed of a non-sintered body, as a binder. By configuring the fuel absorption body, unburned products such as soft carbon and tar that are likely to be formed in the vaporization part of the absorption body are suppressed or decomposed. Furthermore, by configuring the wicking body with a porous body in which the silicate lime and aggregate, or silicate lime and aggregate, and a metal oxide catalyst are uniformly mixed and bonded, unburned products can be suppressed. It is possible to provide a liquid fuel combustion device that is stable for a long time and can be disassembled. Note that the necessary conditions for this porous body are as follows. (1) The porous material must have excellent capillary action. (2) The porous material must have excellent heat resistance and corrosion resistance. (3) The porous material must not only serve as a catalyst carrier, but also be able to sufficiently withstand the manufacturing process in which the catalyst is supported. (4) The porous body must have a structure that can efficiently convert the calorific value of the heating element installed inside the porous body into heat of vaporization of liquid fuel (kerosene). (5) The porous body must be able to vary the amount of kerosene vaporized depending on the calorific value of the heating element (the amount of kerosene vaporized can be varied depending on the surrounding conditions of the porous body). (6) Porous materials are less likely to generate unburned products such as tar in their vaporization parts. etc. Next, one embodiment of the present invention will be described based on the accompanying drawings. As shown in FIGS. 1A and 1B, a closed container 1 is provided with a liquid fuel supply port 2, an air supply port 3, and a mixed gas outlet 4, and inside this closed container 1, a liquid fuel supply port 2, an air supply port 3, and a mixed gas outlet 4 are provided. A suction body 5 is provided. In addition, a composite heating element 6 whose surface is coated with a heat-resistant material is mounted inside the absorbent body 5, and therefore most of the calorific value of the composite heating element 6 is efficiently transferred to the absorbent body 5. Heat is transferred by conduction, and as a result, the liquid fuel sucked up by the wicking body 5, for example, is effectively vaporized. Moreover, the kerosene vaporized at this time is automatically sucked up in an amount corresponding to the above vaporized amount due to the excellent capillary action of the wicking body 5, and a steady state is maintained. That is, by appropriately selecting the relationship among the kerosene suction capacity of the wicking body 5, the calorific value of the composite heating element 6, the surface area of the kerosene vaporizing section, etc., it is possible to achieve extremely efficient heating for the amount of heat supplied by the composite heating element 6. Moreover, a kerosene vaporized gas generation source with excellent responsiveness can be obtained. At this time, since the vaporization of kerosene mainly occurs on the contact surface of the composite heating element 6 and the surrounding area, the air supply port 3 is designed to promote the vaporization of kerosene by the air flowing in from the air supply port 3, and to separate the vaporized kerosene from the air supply port 3. It is preferable to arrange the mixed gas so that it is completely mixed and flows out from the mixed gas outlet 4. By guiding the mixed gas thus obtained to various burner sections depending on the purpose of use, an economical liquid fuel combustion apparatus can be constructed. The wicking body 5 is made of a porous body containing lime silicate as a binder, a base aggregate, a metal oxide catalyst, and an auxiliary material. Each component will be explained in detail below. A. Lime silicate As the silicate lime, one commercially available as Portland cement can be used. Main component (binder) of absorbent body 5 used in the present invention
is Portland cement, which is distinguished from alumina cement. Portland cement, or lime silicate, is generally represented by mSiO ₂ .nCaO, and alumina cement, or lime aluminate, is represented by mAl ₂ O ₃ .nCaO. Alumina cement has high heat resistance and fast hardening speed, and is a preferable cement from the viewpoint of producing porous bodies. However, alumina cement is more expensive and has lower mechanical strength than Portland cement. On the other hand, the Portland cement of the present invention has low heat resistance, as it is said to have a heat resistance of around 300°C, but the boiling point of kerosene, light oil, etc. is generally around 150 to 250°C.
It has sufficient heat resistance as a structure for vaporizing liquid fuels such as kerosene, is itself a binder, and is also an extremely excellent kerosene decomposition catalyst. Next, the characteristics of the absorbent body 5 containing silicate lime will be described. 1. Because it is strongly alkaline, it can accelerate the decomposition of kerosene. 2. Good porosity that improves capillarity can be obtained. 3 Furthermore, when the absorbent body 5 made of lime silicate is used as a carrier, for example when supporting chloroplatinic acid, the surface area of the carrier itself is large (specific surface area 10 to 50 m ² /g), and the adhesion efficiency (adhesion strength) of the catalyst is increased. ) is also large, and the wetting phenomenon of the catalyst salt with the solvent (water, alcohol, etc.) is large, and the catalyst can be effectively homogeneously dispersed and supported.
In addition, since the carrier is a strong alkali, the catalyst is supported on the carrier surface (due to the alkaline nature, the catalyst salt becomes hydroxide on the carrier surface,
(does not penetrate deeply), the amount of catalyst is small, the catalytic ability can be increased, and the wear strength is also high. 4. Unlike conventional ceramic sintered bodies, the wicking body 5 does not need to be sintered and can be molded and solidified at room temperature. More importantly, the sintered body undergoes thermal shrinkage of about 10 to 30% compared to the original mold, making it difficult to maintain uniform mold precision of the wicking body 5. However, as in the present invention, silicate lime When used, since it is a non-sintered body, the mold accuracy can be kept at 2% or less. 5 When the absorbent body 5 containing silicate lime is heat-treated at 250° C. or higher, the bound water of the silicate lime is dehydrated and the porosity is improved. B. Base aggregate The base aggregate can improve the porosity of the wicking body 5, improve the spalling resistance (preventing cracks and cracks in the vaporization structure), and more importantly, it can improve the porosity of the wicking body 5, and more importantly, it can improve the porosity of the wicking body 5. A catalyst with excellent resolution can also be used as the base aggregate. Preferred base aggregates include silica base aggregate, silica alumina base aggregate, and alumina base aggregate, and mineral phases include silicate minerals, mullite, corundum, sillimanite, β-alumina, and magnesia, chromium, Dolomite, maguro, and chromag type materials can be used.
More specifically, examples of the silica base aggregate include silica sand and silica sand. These base aggregates are
The main component is SiO ₂ . Silica-alumina base aggregates include siyamoto, waxite, high alumina, etc., and the main component is SiO ₂ - _{Al 2} O ₃ . α-Al ₂ O ₃ , β- as alumina base aggregate
Examples include Al ₂ O ₃ and γ-Al ₂ O ₃ . Note that it is also possible to use aluminum hydroxide as a starting material instead of using alumina or the like. More generally, these base aggregates are crushed to a certain extent, or commercially available silica sand, alumina, siyamoto, etc. are used. Furthermore, materials that share the base aggregate and catalyst include natural zeolite, synthetic zeolite, acid clay, activated clay and derivatives thereof, and the aforementioned silica alumina, silica magnesia, alumina boria, etc., which are most preferred for the present invention. It is the base aggregate. Other materials such as bentonite and kaolin can also be used. C Metal oxide catalyst Metal oxides include things like manganese dioxide and complex oxides like ferrite.
Particularly preferred are transition metal oxides consisting of Fe, Mn, Co, Ni, Cr, and Cu. Among these oxides, relatively inexpensive metal oxides are manganese oxide and iron oxide. Although manganese dioxide, natural manganese dioxide, and chemically treated manganese dioxide are good, it is preferable to use electrolytic manganese dioxide from the viewpoint of catalyst homogeneity because it is rich in material. The above-mentioned metal oxide may be used by mixing or mixing with it a thermally decomposable salt such as a carbonate, a basic carbonate, a hydroxide, or a nitrate, which can become the above-mentioned oxide by heat treatment or the like. The metal ion M forming the composite oxide is
There are Mn ²⁺ , Fe ²⁺ , Co ²⁺ , Ni ²⁺ , Cu ²⁺ , Zn ^{2+ ,} etc., and it is represented by Mo・Fe ₂ O ₃ and is a group of iron oxides. It contains ²⁺ . Usually, M can be mixed with two or more divalent ions to form a solid body. Other metal ions include Mn ²⁺
is valid. The preferred composition is Mn-Fe-Zn system, and the compound form is MnFe ₂ O ₄ + ZnFe ₂ O ₄
It is a solid body represented by . Although it is not particularly clear, this is thought to be due to the fact that composite oxides containing zinc oxide have strong bonding strength and are thermally stable. The preferred composition of the solid body itself is the composition ratio shown below. Fe ₂ O ₃ (mol%) 40-80% MnO (mol%) 10-40% ZnO (mol%) 1-25% Although the composition of the solid is not limited to the above, price considerations , Fe from the performance point of view
-Mn-Zn system is the best. Note that it is also possible to use CuO, CrO, CoO, or NiO instead of MnO. The characteristics of the absorbent body 5 containing such a metal oxide catalyst will be described. 1. Unburnt products such as soft carbon, hard carbon, and tar that are likely to be formed on the absorbent body 5 can be suppressed or oxidized and decomposed. 2. By lowering the gasification temperature (decomposition) of kerosene and light oil, unburned products such as tar can be suppressed. 3. Containing metal oxides makes it porous and improves capillary action (i.e. kerosene wicking ability). 4. When unburned products such as tar are fired, they can be oxidized and decomposed at low temperatures. and so on. D Auxiliary materials The following can be added as auxiliary materials. In addition to the above-mentioned base aggregate, calcium silicate, activated carbon, calcium carbonate, carbon,
Add a blowing agent (thermally decomposable organic compound, etc.). (b) As reinforcement (mechanical strength),
It is also possible to add glass fibers, asbestos, metal fibers, etc. To summarize the preferable composition ratios of the wicking body 5, a) lime silicate 20-100% by weight b) base aggregate 0-80% by weight c) metal oxide catalyst 0-80% by weight d auxiliary material 0-50% by weight be. Next, a method for manufacturing the absorbent body 5 will be described. Portland cement containing silicate lime, base aggregate, metal oxide catalyst and auxiliary materials as required are first dry-mixed, then enough water is added for molding, wet-mixed, and molded into the required shape. A porous body is obtained by curing. Using the above manufacturing method, a porous body with a width of 70 mm, a length of 150 mm, and a thickness of 10 mm was created with the composition shown in Table 1 below, and it was immersed in the oil level of the following kerosene to examine the height at which the kerosene would be sucked up by capillary action. The results shown in Figure 2 were obtained. Figure 2 A shows a porous body using unglazed clay as a porous substrate. It is a porous foamed bisque body.
A to F have the compositions shown in Table 1 below.
As understood from FIG. 2, in the wicking body 5,
It can be seen that capillarity varies significantly depending on the material, manufacturing method, and composition.

[Table] Next, FIG. 3 shows a specific embodiment that takes advantage of the basic principle of the present invention shown in FIG. This FIG. 3 is a concrete example of the liquid fuel combustion apparatus shown in FIG. 1, and as shown in FIG. The combustion flame of the mixed gas is formed at the flame ports 9 and 10.
In addition, 11 is a trivet, 12 is a heat insulating material of the closed container 1, and 13 and 14 are input resistors of the composite heating element 6. Further, in this embodiment, air is supplied by a blower 15, and kerosene is supplied with the liquid level kept constant by a leveler 16. Of course, the amount of combustion can be varied over a wide range by adjusting the input to the composite heating element 6 and the amount of air supplied. Next, a method for installing the composite heating element 6 on the absorbent body 5 will be described. As shown in FIGS. 4a and 4b, the suction body 5 is provided with a through hole 20 in the upper part thereof for installing a composite heating element 6 therein. The absorbent body 5 is configured to be porous so that it can absorb kerosene. Next, using the furnace shown in Fig. 3, the composite heating element 6
The surface of a 15Ω heating wire was coated with alumina powder of 30 to 50 microns uniformly by plasma spraying method, and the wicking body 5 was made of six types of porous bodies shown in Table 1 above. carried out combustion. The heat value of the composite heating element 6 was set to 40 W, and the heat value and the time until tar was generated on the wicking body 5 were investigated, and the results are shown in Table 2 below.

[Table] Table 3 below shows some of the porous bodies shown in Table 2 with noble metal catalysts supported, and 0.5% in kerosene.
As in Table 2, the time required for tar to form was investigated using abnormal kerosene to which salad oil was added.

【table】

[Table] The method of supporting a catalyst on the porous layer of the absorbent shown in Table 3 will be briefly described. The catalysts shown in the examples of the present invention are noble metal catalysts, including platinum, rhodium, and palladium. In particular, after dissolving chloroplatinic acid in a solvent (water: alcohol = 50:50) to a concentration of 2 g/ A chloroplatinic acid solution was applied to the porous body by a spray method to a concentration of 0.01% by weight, and after drying, it was heat-treated at 300℃. Below, these results will be compared. In Tables 1 and 2, A and B are both porous materials whose main component is clay, but B has a higher degree of porosity, has better kerosene absorption ability, has a higher calorific value, and is less likely to turn into tar. Although the time required for taring has also been improved, especially for abnormal kerosene as shown in Table 2, even if a noble metal catalyst is supported, the time required to turn into tar has not been improved. All of them are porous bodies containing silicate lime, but the kerosene suction height differs depending on the composition and composition ratio. Among them, E and F were particularly excellent, and also showed excellent results in terms of calorific value and time until tar generation (both normal oil and abnormal oil). Among these, as detailed in Table 3, when abnormal oil is used, the time until it turns into tar is significantly shorter than that of normal oil. However, the difference between 2 in Table 1 and 2 in Table 3 is that there is almost no difference in the time it takes to turn into tar between normal oil and abnormal oil.
This is because the material constituting the porous body itself is a cracking catalyst that decomposes kerosene, tar, etc., as mentioned above. Furthermore, it is thought that this is because the platinum supported also functions as an oxidation catalyst that oxidizes substances with lower molecular weight. Furthermore, from these results, if the kerosene suction capacity is 10 mm/30 seconds or more, it can sufficiently serve as the wicking body for the purpose of the present invention, but as shown in Table 2 A, 10 mm/30 seconds If the kerosene wicking capacity is below, the calorific efficiency of the kerosene vaporizer will be poor, and tar will form on the porous surface in a short period of time, impairing the kerosene vaporizer's performance (rapid drop in calorific value). cormorant. From these results, it is preferable that a wicking body that achieves the purpose of the present invention has alkalinity and a kerosene absorption capacity of 10 mm/30 seconds or more, and particularly a kerosene absorption capacity of 15 mm/30 seconds or more. A wicking body that has the ability to lift can perform a stable function for a long period of time. What is important here is that the base aggregate and the metal oxide catalyst are necessary substances for obtaining the absorbent, and at the same time, they work to suppress the generation of tar due to foreign oils, foreign oils, and the like. Noble metal catalysts are also effective in inhibiting and decomposing tar content. In the examples, Al ₂ O ₃ was used as the base aggregate, and manganese dioxide and ferrite were described as the synthetic zeolite and metal oxide. However, in the present invention, the base aggregate, metal oxide, and auxiliary material are It is also effective to use As described in detail above, according to the liquid fuel combustion apparatus of the present invention, the liquid fuel is stably vaporized, so that good combustion can be stably obtained over a long period of time. The present invention can be applied to combustors in all fields, such as cooking appliances, hot air blowers, and kerosene stoves, by connecting to various types of burner sections.

[Brief explanation of the drawing]

FIG. 1A is a sectional view of a main part of a liquid fuel combustion device according to an embodiment of the present invention, FIG. 1B is an enlarged sectional view of a main part of the same device, and FIG. 2 is a graph explaining the characteristics of the device. FIG. 3 is a sectional view of a liquid fuel combustion device according to another embodiment of the present invention, and FIGS. 4a and 4b are an enlarged front view and an enlarged side view of the suction body of the liquid fuel combustion device of FIG. 1. . 5...Suction body, 6...Composite heating element.

Claims (1)

[Claims] 1. It has a burner section and a liquid fuel suction body that vaporizes and sends fuel to the burner section, and this liquid fuel suction body is made of a porous body using lime silicate as a binder. , a liquid fuel combustion device in which a heating element is provided in the vaporization part and at least one of noble metals such as platinum, rhodium, palladium, etc. is supported on the surface. 2. The liquid fuel combustion device according to claim 1, wherein the kerosene suction speed of the suction body is 10 mm/30 seconds or more. 3. The liquid fuel combustion device according to claim 1, wherein the absorbent body is a porous body formed by uniformly mixing at least lime silicate and aggregate.