JP2020082059A - Burned residue manufacturing apparatus and manufacturing method - Google Patents

Abstract

To provide a manufacturing apparatus and a manufacturing method by which burned residue, which is burned residue of vegetable biomass and generates heat by micro wave irradiation, can be efficiently and continuously produced.SOLUTION: There is provided a burned residue manufacturing method for continuously supplying vegetable biomass and air into a combustion furnace, causing self-burning of the vegetable biomass in air, and continuously manufacturing burned residue. According to this method, the burned residue contains silicon dioxide as a main component and contains carbon element, and generates heat by micro wave irradiation, and a temperature when burning the vegetable biomass is 1000 to 2000°C. Further, provided is a burned residue manufacturing apparatus for performing said manufacturing method.SELECTED DRAWING: Figure 1

Description

The present invention relates to an apparatus for producing an incineration residue using plant biomass as a raw material and a method for producing the same.

Since a large amount of plant biomass such as rice husks, rice straw, bamboo, and thinned wood is generated every year, various effective utilization methods have been conventionally studied. In recent years, a large amount of fuel is being used as a fuel for biomass power plants. Since plant biomass such as rice husk contains a relatively large amount of silicon dioxide, a new method of utilizing the silicon dioxide is also under study.

For example, Patent Document 1 discloses a method for producing siliceous fertilizer by burning rice husks in a firing furnace to obtain porous activated siliceous ash.

Japanese Patent No. 4894057

When plant biomass such as rice husk is burned at high temperature for a long time, almost all organic combustibles are incinerated, leaving a residue. The present inventors focused their attention on the effective use method of this incineration residue.

Conventionally, an electric heater using a nichrome wire, an infrared lamp, a burner using a flammable gas or flammable oil, etc. have been used as a heat source of a heating device. As a heating device using a heat source other than the above, a heating device using microwaves such as a microwave oven is known.

The present inventors have surprisingly found that when the incineration residue of plant biomass is irradiated with microwaves, it rapidly generates heat up to several hundreds of degrees Celsius. Furthermore, it was found that the heat generation phenomenon occurs repeatedly every time microwave irradiation is repeated.

The present invention has been made in view of such a situation. That is, the present invention is to provide a production apparatus and a production method capable of efficiently and continuously producing an incineration residue of plant biomass, which is heated by irradiation with microwaves. I am trying.

The inventors of the present invention are capable of sustaining self-combustion of plant biomass in air without using other fossil fuels, being heated to 1000° C. or higher by self-combustion alone, Being able to continuously produce incineration residues by carrying out self-combustion of volatile biomass while carrying it by air, and that it is necessary to set a specific combustion temperature to generate incineration residues that generate heat by irradiating microwaves Found. The present invention has been made based on such findings. That is, the present invention has the following configurations.

(1) A device for producing an incineration residue that continuously produces an incineration residue by self-combusting plant biomass in the air, the incineration residue containing silicon dioxide as a main component and a carbon element, Heat is generated by irradiating with microwaves, a storage tank for storing the plant biomass, a transfer pipe for transferring the plant biomass by air, and sending air into the transfer pipe. A blower for, a combustion furnace for self-burning the plant biomass, an accumulation tank for accumulating the incineration residue, a dust collector for accumulating the incineration residue present in the exhaust gas after combustion, An incineration residue manufacturing apparatus, comprising: a discharge device for discharging exhaust gas after combustion.

(2) The apparatus for producing an incineration residue according to (1), wherein the temperature in the combustion furnace can be set to 1000 to 2000°C.

(3) A method for producing an incineration residue, which comprises continuously supplying a plant biomass and air into a combustion furnace, self-combusting the plant biomass in the air, and continuously producing an incineration residue, The incineration residue contains silicon dioxide as a main component, contains a carbon element, and generates heat when irradiated with microwaves, and the temperature at which the plant biomass is burned is 1000 to 2000°C. A method for producing an incineration residue, comprising:

(4) In the above (3), the mixing ratio of the plant biomass and air at the time of combustion is 1:1.5×10 ⁵ to 1:5.5×10 ⁵ by volume. A method for producing the incineration residue described.

INDUSTRIAL APPLICABILITY The apparatus and method for producing an incineration residue of the present invention can efficiently produce an incineration residue that is a plant biomass incineration residue and generates heat by irradiating microwaves in a continuous manner.

It is a typical sectional view of the manufacturing apparatus of the incineration residue of this embodiment.

Hereinafter, the present invention will be specifically described. The embodiments shown below are examples, and the present invention is not construed as being limited to these embodiments.

The incineration residue of the present embodiment is obtained by self-burning plant biomass in air, contains silicon dioxide as a main component, contains a carbon element, and generates heat by irradiation with microwaves. .. The details of this embodiment will be described below.

(Vegetable biomass)
The plant biomass of the present embodiment contains silicon. Specific examples thereof include rice husk, rice straw, straw, wood, bark, bamboo, bagasse, coconut shell and the like. Among these, rice husks are preferable from the viewpoints of handling and availability. In the following, rice husk, which is a typical plant biomass, will be described as an example.

About 70 to 90% by mass of rice husk is an organic component mainly composed of cellulose, and the remaining about 10 to 30% by mass is an inorganic component. Its inorganic component is mainly silicon dioxide (silica), and it contains a trace amount of mineral components.

(Incinerator production equipment)
FIG. 1 is a schematic cross-sectional view of the incineration residue manufacturing apparatus of this embodiment. The incineration residue manufacturing apparatus includes a storage tank 1 for storing plant biomass, a pipe 4 for transporting the plant biomass by air, a blower 3 for feeding air into the pipe for transport, and a plant plant. A combustion furnace 6 for self-burning biomass, an accumulation tank 16 for accumulating incineration residues, a dust collector 19 for accumulating incineration residues present in the exhaust gas after combustion, and exhausting exhaust gas after combustion And a discharge device for.

The vegetable biomass as a raw material is put into the storage tank 1. A so-called hopper is usually used as the storage tank 1. A discharge pipe and an opening/closing valve 2 are provided below the storage tank 1. The storage tank 1 can continuously supply a required amount of plant biomass from the lower portion of the storage tank 1 into the transport pipe 4.

The transfer pipe 4 is provided with a blower 3 for sending air into the transfer pipe 4. The air supplied by the blower 3 plays a role of transporting the plant biomass in the transport pipe 4 by an air flow. The air supplied by the blower 3 also plays a role of supplying oxygen for burning the plant biomass.

The mixing ratio of plant biomass and air at the time of combustion is determined by the amount of plant biomass input from the storage tank 1 and the amount of air supplied by the blower 3.

From the viewpoint of heat retention and safety of the heat generated inside, the inside of the vessel wall 7 of the combustion furnace 6 is covered with a heat resistant ceramic style (not shown). Since the heat-retaining performance of the heat-resistant ceramic style enables the inside to be maintained at a high temperature of 1000° C. or higher, it is preferable to pay close attention to the type, shape, and amount of use of the heat-resistant ceramic style. The temperature in the combustion furnace 6 can be set to 1000 to 2000°C.

The combustion furnace 6 is a steel box type, and the inside thereof has an inclined cross section that obliquely descends from an inlet (left side in the figure) toward an outlet (right side in the figure). Further, the combustion furnace 6 is partitioned into a plurality of chambers by a plurality of partition plates 8. In this embodiment, the number of rooms is four, but the number of rooms is preferably 3-5. A plurality of floor plates 9 having a trapezoidal cross section are installed at the bottom of the combustion furnace 6 so as to descend stepwise for each of the plurality of rooms.

The plant biomass and air are introduced into the combustion furnace 6 through the introduction port 5 through the transfer pipe 4. The plant biomass and air are first introduced into the main combustion chamber 10. Of the plurality of chambers partitioned by the plurality of partition plates 8, the main combustion chamber 10 has the largest volume and the ceiling is also high.

First, the combustion reaction of vegetable biomass is started in the main combustion chamber 10. After that, the combustion product moves to the next first auxiliary combustion chamber 11 by its own weight due to the inclination of the stepped floor plate 9 at the bottom of the combustion furnace 6 while continuing the combustion. Similarly, the combustion product moves to the next second sub combustion chamber 12 and the third sub combustion chamber 13 by its own weight while continuing the combustion.

In the third combustion chamber 13, the incineration residue that has been substantially burned is discharged from the discharge port 14 to the outside of the combustion furnace 6 by its own weight. A discharge door 15 is installed below the discharge port 14, and when the discharge door 15 is opened, the incineration residue is accumulated in the accumulation tank 16 therebelow.

At the ceiling of the third auxiliary combustion chamber 13 of the combustion furnace 6, a discharge port 17 for discharging exhaust gas is installed. The exhaust gas after combustion is discharged from the exhaust port 17, passes through the exhaust gas pipe 18, and enters the dust collector 19. Part of the incineration residue is scattered and discharged together with the exhaust gas. Therefore, the dust collector 19 accumulates the incineration residue existing in the exhaust gas. The accumulated incineration residue is accumulated in the second accumulation tank 20. As the dust collector 19, a known dust collector such as a cyclone can be appropriately selected and used.

The exhaust gas after passing through the dust collector 19 is exhausted to the outside from an exhaust duct 21 which is an exhaust device for exhausting the exhaust gas. If necessary, an exhaust gas filter, a cleaning device, etc. may be installed.

(Method of manufacturing incineration residue)
The method for producing an incineration residue of the present embodiment is a production method in which plant biomass and air are continuously supplied into a combustion furnace and the plant biomass is self-combusted in the air to continuously produce an incineration residue. Is. The incineration residue manufacturing method of the present embodiment can be carried out by using the above-described incineration residue manufacturing apparatus.

Vegetable biomass burns in the air. It is necessary to externally supply the ignition source when starting the combustion. However, once the plant biomass starts burning, it continuously supplies the plant biomass and air to the combustion furnace to keep the generated heat from being dissipated so that it can continue to burn only by self-combustion. be able to. That is, the incineration residue of vegetable biomass can be continuously produced.

The pressure at which the plant biomass is burned may be atmospheric pressure or pressure close to atmospheric pressure. The temperature at which the plant biomass is burned can be adjusted by the amount of plant biomass and air supplied per hour, the ratio of plant biomass and air supplied, the internal structure of the combustion furnace, the heat retention of the combustion furnace, etc. it can.

By fixing various combustion conditions to a fixed condition, the combustion reaction is constantly continued, a specific combustion temperature is maintained, and an incineration residue under a constant combustion condition can be continuously produced.

Here, in order that the incineration residue contains silicon dioxide as a main component, contains a carbon element, and generates heat by being irradiated with microwaves, the temperature at which the plant biomass is burned is 1000 to 2000°C. It is necessary to be. Further, the temperature at which the plant biomass is burned is preferably 1000 to 1900°C, and more preferably 1200 to 1900°C.

In order to keep the temperature when burning the plant biomass at 1000 to 2000° C., the mixing ratio of the plant biomass and the air at the time of burning is 1:1.5×10 ⁵ to 1 by volume. : 5.5×10 ⁵ , preferably 1:2×10 ⁵ to 1:5×10 ⁵ .

The burning time when burning the vegetable biomass is preferably 5 to 15 hours, and more preferably 8 to 12 hours. Here, the combustion time means the time during which the vegetable biomass stays in the combustion furnace 6.

(Incineration residue)
The incineration residue of the present embodiment contains silicon dioxide as a main component and carbon element as a minor component. Here, having silicon dioxide as a main component means that the content of silicon dioxide with respect to the incineration residue exceeds 50 mass %.

The incineration residue of this embodiment generates heat by irradiation with microwaves. The incineration residue can be rapidly heated to a high temperature of 300° C. or higher in a short time within 10 minutes by irradiation with microwaves, for example. It can be continued for several hours and can be repeatedly heated.

As microwave generation means for irradiating the incineration residue with microwaves, there are microwave oscillators such as magnetrons, klystrons, gyrotrons, and traveling wave tubes. Of these, the magnetron is common. The frequency of microwaves is in the range of 0.3 to 30 GHz, but microwaves having a frequency of 2.45 GHz are usually used. By changing the oscillation output (W) of the microwave oscillator, the heat generation energy fluctuates, and the heat generation temperature of the incineration residue can be controlled.

It is presumed that the incineration residue exhibits such a peculiar exothermic phenomenon because a small amount of elements such as carbon element and metal element contained in the incineration residue cause induction heating, dielectric heating, etc. by irradiation of microwaves. It is also presumed that the carbon element and the metal element are present in the structure containing silicon dioxide as the main component in an appropriately finely dispersed state. Further, it is presumed that a part of the carbon element is bonded to the silicon element to form silicon carbide.

The incineration residue of the present embodiment contains silicon dioxide as a main component, and the content of silicon dioxide is preferably 60 to 96 mass %. Further, the content of silicon dioxide is more preferably 60 to 85% by mass, and further preferably 70 to 85% by mass from the viewpoint of heat generation performance.

The incineration residue needs to contain carbon element. 28 mass% or less is preferable, as for content of the carbon element in an incineration residue, 3-28 mass% is more preferable, 5-25 mass% is further more preferable, 5-20 mass% is especially preferable.

The incineration residue preferably contains a metal element. The total content of metal elements in the incineration residue is preferably 10% by mass or less, more preferably 1 to 7% by mass, further preferably 2 to 7% by mass, particularly preferably 3 to 7% by mass. Here, the content of metal elements is a numerical value calculated as the total content of metal oxides when each metal element contained in the incineration residue is replaced with a stable oxide. Examples of the metal element include potassium, magnesium, calcium, iron, aluminum, sodium, manganese, zinc, chromium, titanium and nickel. The existence form of these metals in the incineration residue may be a simple metal, an alloy, a metal oxide, or a composite oxide.

The incineration residue is usually fine particles, and the average particle diameter of the fine particles is about 10 to 300 μm. The shape of the fine particles is not particularly limited. Further, silicon dioxide may be amorphous or crystalline and is not limited.

(Heating element)
In order to use the incineration residue as a heating element utilizing its characteristics, it is preferable that the fine particles of the incineration residue be in a form having excellent handleability. Specifically, it is possible to form a sintered body composed of fine particles of incineration residue and ceramic particles, or to form a molded body in which fine particles of incineration residue are wrapped with ceramics.

The heating element using the incineration residue of this embodiment can be used for various purposes such as heating, drying, temperature control, and reaction. Further, the heating element using the incineration residue of the present embodiment, it can be used for various industrial applications in various technical fields such as food, chemistry, rubber, wood, castings, ceramics, paper, printing, painting, textiles, and medical treatment. it can.

Hereinafter, the present invention will be described in detail with reference to Examples, but the present invention is not limited thereto.

Using the production apparatus described in FIG. 1, the rice husks were self-combusted in the air at a combustion temperature of about 1800° C. and a combustion time of about 10 hours to continuously produce an incineration residue of the rice husks. The mixing ratio of plant biomass and air during combustion was 1:3.5×10 ⁵ by volume. Rice husks from Saitama Prefecture were used as the rice husks. The amount of the obtained incineration residue was about 20 mass% with respect to the rice husk as a raw material. The incineration residue was a black powder. When the incineration residue was analyzed, it was 77% by mass of silicon dioxide and 8.5% by mass of carbon element. In addition, the total content of the metal element when replaced with the metal oxide was 6.2 mass %. As the metal element, potassium, magnesium, calcium, iron, aluminum, sodium, manganese, zinc, etc. were contained. A wavelength dispersive X-ray fluorescence analyzer was used as an analyzer for metal elements.

An incineration residue of rice husk was continuously produced in the same manner as in Example 1 except that the burning temperature was set to about 1000°C. The amount of the obtained incineration residue was about 21% by mass with respect to the rice husk as a raw material. The incineration residue was a black powder. When the incineration residue was analyzed, it was 63 mass% silicon dioxide and 27 mass% carbon element. In addition, the total content of the metal element when replaced with the metal oxide was 4.2 mass %.

About 10 g of each obtained incineration residue was enclosed in a spherical sintered body having a diameter of 15 cm made of soda-lime glass particles, and further enclosed in a spherical vessel made of ceramics with a thickness of 2 mm, It was used as a heating element.

A microwave of 2.45 GHz was irradiated for about 25 minutes using a 700 W magnetron. The surface temperature of the heating element of Example 1 after irradiation was about 400°C. Similarly, the surface temperature of the heating element of Example 2 was about 360°C. Each temperature was measured using a thermocouple.

1 Storage Tank 3 Blower 4 Transfer Pipe 6 Combustion Furnace 8 Partition Plate 9 Floor Plate 10 Main Combustion Chamber 11, 12, 13 Secondary Combustion Chamber 16 Integrated Tank 19 Dust Collector 20 Second Integrated Tank 21 Exhaust Duct

Claims (4)

A plant for producing an incineration residue that continuously produces an incineration residue by self-burning plant biomass in the air,
The incineration residue contains silicon dioxide as a main component, contains a carbon element, and generates heat when irradiated with microwaves,
A storage tank for storing the plant biomass,
A transport pipe for transporting the plant biomass by air,
A blower for sending air into the transfer pipe,
A combustion furnace for self-burning the plant biomass,
An accumulation tank for accumulating the incineration residue,
A dust collector for accumulating the incineration residue present in the exhaust gas after combustion,
An incineration residue manufacturing apparatus, comprising: an exhaust device for exhausting exhaust gas after combustion. The incineration residue manufacturing apparatus according to claim 1, wherein the temperature in the combustion furnace can be set to 1000 to 2000°C. A method for producing an incineration residue, which comprises continuously supplying plant biomass and air into a combustion furnace, self-burning the plant biomass in air, and continuously producing an incineration residue,
The incineration residue is mainly composed of silicon dioxide, contains a carbon element, and generates heat when irradiated with microwaves,
The method for producing an incineration residue, wherein the temperature at which the plant biomass is burned is 1000 to 2000°C. The incineration residue according to claim 3, wherein the mixing ratio of the plant biomass and air at the time of combustion is 1:1.5×10 ⁵ to 1:5.5×10 ⁵ by volume. Manufacturing method.

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