JP2018105610A - Combustion device and biomass fuel - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a combustion apparatus and a biomass fuel for a combustion apparatus in which generation of clinker is prevented without increasing cost. SOLUTION: A combustion apparatus according to the present invention is a combustion apparatus for introducing biomass fuel 2 into a combustion chamber 1 and combusting the biomass fuel 2. As the biomass fuel 2, 20 bark 22 is added to the bamboo material 21. Use a mixture of at least wt%. [Selection] Figure 2

Description

  The present invention relates to a combustion apparatus and a biomass fuel. In particular, the present invention is characterized in that a bamboo material mixed with bark is used as a biomass fuel used in the combustion apparatus.

  Bamboo grows in large quantities and grows quickly. In an abandoned bamboo forest, there are problems such as bamboo spreading around, eroding adjacent forests such as cedar and bushes, and destroying its ecosystem. .

  For this reason, in recent years, there have been an increasing number of local governments, etc., responding to logging for neglected bamboo forests. However, since harvested bamboo is industrial waste, disposal costs are also high, which It is a big burden.

  Therefore, attempts have been made to use the harvested bamboo as biomass fuel.

  An example of a combustion apparatus for burning bamboo as fuel is shown in FIG. As shown in FIG. 1, a grate 11 is provided at the bottom of the combustion chamber 1 to hold a bamboo material 21 as biomass fuel while allowing ventilation, and to drop incinerated ash. Air sent from a blower (not shown) or the like is supplied from the intake port 14 into the combustion chamber 1 through the plurality of holes 11 a of the grate 11.

  An exhaust pipe 13 is provided in the upper part of the combustion chamber 1, and the air exhausted from the exhaust pipe 13 at a high temperature is used by a boiler or the like as heat.

  The combustion chamber 1 is provided with an inlet 12a for supplying biomass fuel, and the inlet 12a is closed by a lid 12 except for supplying biomass fuel.

  The bamboo material 21 held on the grate 11 is ignited using an ignition device (not shown), and the bamboo material 21 is burned. The incineration ash generated by the combustion falls from the hole 11a of the grate 11.

However, bamboo contains a silicon (Si) component and a potassium (K) component, and when bamboo is burned, the eutectic of potassium oxide (K ₂ O) and silica (SiO ₂ ) in bamboo ash A reaction occurs. The melting point of the substance produced by this eutectic reaction is as low as 800 ° C. or less. During the burning of the bamboo, the temperature in the combustion chamber 1 becomes about 1000 ° C., and the substance generated by this eutectic melts, and lava-like clinker (molten ash) X is generated. In particular, bamboo has more potassium than other biomass, and if there is much potassium, the generation of clinker increases.

  The generated clinker X spreads on the grate 11 and closes the hole 11a of the grate 11 to cause an obstacle to continuous combustion.

  As described above, when the clinker X is generated, it becomes impossible to continue combustion by inhibiting the inflow and exhaust of combustion air in the combustion chamber 1. Further, in order to remove the generated clinker X, an operation such as hitting with a hammer or the like is required, and problems such as damage to the grate 11 and the like also occur.

  Therefore, Patent Document 1 proposes to use bamboo as a fuel by modifying bamboo and removing potassium from bamboo. In Patent Document 1, bamboo is atomized to a particle size of 6 mm or less, and the atomized bamboo is immersed in normal pressure water to elute potassium and chlorine to remove potassium and chlorine from the bamboo. And the bamboo immersed in the normal pressure water is dehydrated, and the dehydrated bamboo is used as fuel.

  In the thing of above-mentioned patent document 1, generation | occurrence | production of clinker can be prevented when it uses as a fuel by removing potassium from bamboo by modification | reformation of bamboo. However, in order to modify bamboo, a process of immersing in water and a process of dehydrating bamboo are required, and there are problems such as an increased number of work steps until fuel is used and an increase in cost.

JP 2016-125030 A

  This invention makes it a subject to provide the combustion apparatus and biomass fuel which prevented generation | occurrence | production of clinker, without increasing cost.

  In the combustion apparatus according to the present invention, in order to solve the problems as described above, biomass fuel is introduced into a combustion chamber, and the biomass fuel is combusted. Use a mixture. The bark may be a conifer or a hardwood bark.

  In the above combustion apparatus, the mixing ratio of the bamboo material and the bark of the biomass fuel may be set so that the weight percentage of calcium oxide in the burned ash is greater than the weight percentage of potassium oxide. And it is preferable to mix the said bark 20weight% or more. Thus, by setting the mixing ratio of the bamboo material and the bark of the biomass fuel, the melting point of the combustion ash is not lowered and the generation of clinker can be prevented.

  In the combustion apparatus described above, a grate for supplying air may be provided on the bottom surface of the combustion chamber.

  In addition, the present invention is a biomass fuel used as a fuel for a combustion apparatus, wherein the biomass fuel is obtained by mixing a bark with a bamboo material.

  In the present invention, a combustion apparatus for introducing biomass fuel into a combustion chamber and combusting the biomass fuel, wherein the biomass fuel is mixed with bark in bamboo material, so that the clinker is not subjected to bamboo modification. It is possible to provide biomass fuel that can prevent the occurrence of gas, and it is possible to continue the operation of the combustion chamber using bamboo material without increasing the cost.

It is the schematic which shows the state which the clinker generate | occur | produced in the combustion apparatus using the bamboo material as the conventional biomass fuel. It is the schematic which shows the combustion apparatus using what mixed the bark with the bamboo material as biomass fuel which is embodiment of this invention. It is a figure which shows the mixture ratio of a bamboo material and bark, and the ratio of the metal oxide in the produced | generated ash.

  Hereinafter, a combustion apparatus according to an embodiment of the present invention will be specifically described with reference to the accompanying drawings. The combustion apparatus according to the present invention is not limited to the one shown in the following embodiment, and can be implemented with appropriate modifications within a range not changing the gist of the invention.

  The present inventors paid attention to the generation of clinker generated during the burning of bamboo, and examined whether the generation of clinker can be suppressed by mixing bamboo with other biomass materials.

  There are bark such as cedar and thinned timber as biomass raw materials. This bark becomes industrial waste and is currently used as bark compost, and it is considered that the bark can be used as biomass fuel.

The bark contains a lot of calcium components, and when the bark is burned, calcium oxide (CaO) is generated in the ash. If this calcium oxide (CaO) is present in the ash, even if the bamboo is burned and potassium oxide (K ₂ O) is present in the ash, the melting point of the ash is not lowered and the generation of clinker can be prevented. The inventors have found out.

  Therefore, in the present invention, as a biomass fuel, a bamboo material mixed with bark is used and burned in the combustion chamber 1. An embodiment of the present invention will be described with reference to FIG.

  In FIG. 2 showing the embodiment of the present invention, the combustion apparatus has the same configuration as that shown in FIG. 1, and the same reference numerals are given to the same parts, and the explanation is omitted here in order to avoid duplication of explanation.

  As shown in FIG. 2, the combustion chamber 1 is provided with an input port 12a for supplying biomass fuel, and the biomass fuel 2 in which the bark 22 is mixed with the bamboo material 21 is input from the input port 12a. And the biomass fuel 2 which mixed the bark 22 with the bamboo material 21 is burned. In FIG. 2, the bark 22 is blackened in the biomass fuel 2.

  As described above, clinker can be prevented from being generated by mixing an appropriate amount of bark 22 of conifers such as cedar and straw into bamboo material 21. As a result, combustion air can be supplied from the holes 11a of the grate 11 without closing the holes 11a of the grate 11 by the clinker, and continuous combustion can be continued. The bark 22 may be a hardwood bark other than a conifer.

  In addition, it is better to process the bamboo material so that it is easy to burn, such as by cutting the bamboo as it is or making it into chips.

  Table 1 shows the melting characteristics of ash softening point, melting point, and pour point when mixing bamboo material and bark and changing the mixing ratio and burning. JIS M8801 “Measurement of melting temperature of ash” The results measured in accordance with. The ash that is burned in the three states of 30% by weight bamboo material, 70% by weight bark, 50% by weight bamboo material, 50% bark, 80% by weight bamboo material, and 20% bark is collected. A test cone was made using the ash, heated continuously in the furnace, and the temperature when a specific change in the shape of the test cone occurred was measured. Here, the softening point is the temperature at which the apex of the test cone starts to melt and becomes round, the melting point is the temperature when the test cone melts and its height becomes ½ the apparent width of the bottom, The melting point is the temperature at which the melt flows to the support and becomes 1/3 the height at the melting point.

  As shown in Table 1, when the bark is mixed with the bamboo material and burned, the melting point is 1250 ° C. even in the combustion ash when the bamboo material is 80% by weight and the bark is 20% by weight. Since the temperature in the combustion chamber 1 is about 1000 ° C., it can be seen that the combustion ash does not melt and the generation of clinker can be prevented.

Next, the weight of the metal oxides of potassium oxide (K ₂ O), calcium oxide (CaO), and silica (SiO ₂ ) generated when the bark is mixed with the bamboo material and the mixture ratio is changed and burned. FIG. 3 shows the results of measurement and the percentage by weight. In FIG. 3, black circles are silica (SiO ₂ ), black triangles are potassium oxide (K ₂ O), and black squares are calcium oxide (CaO).

As shown in FIG. 3, the ratio of silica (SiO ₂ ) does not change much even when the mixing ratio of bamboo material and bark is changed. However, when the mixing ratio of bamboo material is increased, potassium oxide (K ₂ O) is increased. ) Increases and calcium oxide (CaO) decreases. And, up to 85% by weight of bamboo material and 15% by weight of bark, the calcium oxide (CaO) in the ash is more than the potassium oxide (K ₂ O). In a state where there is a lot of calcium oxide (CaO), the melting point of ash is 1127 ° C. or higher, and clinker is not generated.

Therefore, the mixing ratio of the bamboo material 21 and the bark 22 of the biomass fuel should be set so that the weight percent of calcium oxide (CaO) in the burned ash is greater than the weight percent of potassium oxide (K ₂ O). That's fine.

As shown in FIG. 3, when the bamboo material 21 is 85% by weight and the bark 22 is 15% by weight, the calcium oxide (CaO) in the ash is more than the potassium oxide (K ₂ O), but both the bamboo and the bark are grown in nature. Since calcium and potassium present in these materials vary, 20 wt. Of bark 22 is ensured so that the amount of calcium oxide (CaO) in the ash is surely greater than that of potassium oxide (K ₂ O). It is desirable to use the biomass fuel 2 in which the bamboo material 21 is mixed at 80% by weight or less.

  By the way, the bark is easily entangled, and the bark alone becomes a lump and is difficult to use as fuel. However, when the bark 22 and the bamboo material 21 are mixed, the bamboo material 21 suppresses the entanglement of the bark 22 and the lump. There is also an advantage that it becomes easy to handle as the biomass fuel 2. In this way, biomass fuel that does not generate clinker can be provided by using bamboo and bark that have not been used as industrial waste without reforming bamboo.

  In the case where the grate 11 is provided on the bottom surface of the combustion chamber 1, when the biomass fuel 2 in which the bamboo material 21 and the bark 22 of the present invention are mixed is used for combustion, clinker is not generated and combustion air is not generated. While supply can be maintained, ash falls from the hole 11a of the grate 11 downward.

  The combustion apparatus shown in FIG. 2 is provided with a grate 11 for supplying air to the bottom surface of the combustion chamber 1 and supplying combustion air from the bottom, but the form of the combustion chamber is not limited to this, and various combustion modes are provided. The present invention is applicable.

1: Combustion chamber 2: Biomass fuel 21: Bamboo material 22: Bark 11: Grate 11a: Hole 12: Lid 12a: Input port 13: Exhaust pipe 14: Intake port

Claims (6)

A combustion apparatus for introducing biomass fuel into a combustion chamber and combusting the biomass fuel,
A combustion apparatus comprising a bamboo material mixed with bark as the biomass fuel. The combustion apparatus according to claim 1, wherein
A combustion apparatus characterized in that the bark is a bark of a conifer or a broad-leaved tree. The combustion apparatus according to claim 1 or 2,
A combustion apparatus, wherein the mixing ratio of bamboo material and bark of the biomass fuel is set so that the weight percentage of calcium oxide in the burned ash is greater than the weight percentage of potassium oxide. The combustion apparatus according to any one of claims 1 to 3,
A combustion apparatus characterized by mixing at least 20% by weight of the bark. The combustion apparatus according to any one of claims 1 to 4,
A combustion apparatus comprising a grate for supplying air to a bottom surface of the combustion chamber. A biomass fuel used as a fuel in a combustion apparatus, wherein the biomass fuel is a material obtained by mixing bark with bamboo material.

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