JP7680869B2 - Semi-carbide manufacturing apparatus, semi-carbide, thermal power generation fuel, and power generation method - Google Patents

Description

The present invention relates to a semi-carbide manufacturing device, semi-carbide, thermal power generation fuel, and a power generation method.

Methods of reusing biomass generated from households and industries as fuel have been studied. In this specification, "biomass" refers to resources derived from living organisms, excluding fossil resources. Biomass has been attracting attention as a carbon-neutral fuel.

In the above method, rather than using biomass as fuel as is, a technology is being considered that improves the energy density per unit mass by partially pyrolyzing it at low temperatures. This technology is referred to as "semi-carbonization" in this specification. In this sense, the "semi" in the term semi-carbonization does not mean half (50%), but rather means that the reaction is terminated while leaving behind the carbonizable portion (organic matter), and the carbonization process is only halfway complete.

More specifically, "semi-carbonization" is a technique in which biomass is heat-treated at low temperatures to increase the ratio of carbon components per unit mass. It is known that pyrolysis at 200°C to 300°C is preferable for semi-carbonization.

By heat treating at low temperatures, moisture is removed from the biomass. Furthermore, the biomass is pyrolyzed to produce gaseous components, which are then removed from the biomass. This reduces the mass of the biomass.

On the other hand, the remaining part (solid) of the biomass after the moisture and gas components have been removed by the above reaction contains a large amount of carbon.

As a result, biomass that has been heat-treated at low temperatures has a relatively higher carbon content than biomass before heat treatment, which improves the energy density per unit mass.

For example, Patent Document 1 discloses a manufacturing device for semi-carbonizing biomass. The manufacturing device described in Patent Document 1 is a so-called rotary kiln type device that has a cylindrical rotary shell that is driven to rotate.

JP 2019-045078 A

The rotary kiln-type device described in Patent Document 1 requires a large amount of energy to drive the large rotary shell and heat the raw materials fed inside. For this reason, there was a demand for a device that could produce semi-carbide using less energy than conventional methods.

One of the uses for the semi-carbide is expected to be to mix it with coal and use it as fuel for thermal power generation. When semi-carbide, particularly semi-carbide derived from biomass, is used for such purposes, it is possible to ignore some of the carbon dioxide emissions from power generation, based on the idea of carbon neutrality. On the other hand, when considering using semi-carbide as a power generation fuel, devices that require a lot of energy to produce semi-carbide, such as the device described in Patent Document 1, cause an increase in the total energy required for power generation. From this perspective, too, there has been a demand for a device that can produce semi-carbide using less energy than before.

The present invention has been made in consideration of these circumstances, and aims to provide a semi-carbide manufacturing device that can produce semi-carbide with less energy than conventional methods. Another aim is to provide semi-carbide suitable for use as fuel for power generation. Another aim is to provide a thermal power generation fuel that contains such semi-carbide, and a power generation method that uses such thermal power generation fuel as fuel.

To solve the above problems, one aspect of the present invention includes the following aspects:

[1] A cylindrical main body extending vertically and having an internal space for heat-treating raw materials, a heating section for heating the raw materials, a temperature measuring section for measuring the temperature of the internal space, an oxygen supply section for supplying oxygen to the internal space, an input section for inputting the raw materials into the internal space, an output section for discharging the product resulting from the processing of the raw materials from the internal space, and a control section for controlling the operation of the oxygen supply section, the input section, and the output section, the main body having an input port above the heating section for inputting the raw materials and an output port below the internal space for discharging the product, the input section being connected to the input port and controlling the input speed of the raw materials, and the output section discharging the product from the output port. The device controls the discharge rate of the product, the heating unit is a cylindrical member with a closed upper end and is provided below the internal space, the main body unit and the heating unit are arranged coaxially with the center axis of the main body unit and are spaced apart in the radial direction of the main body unit, the temperature measurement unit has a first measurement unit provided above the heating unit and below the inlet and a second measurement unit provided below the apex position of the heating unit, and the control unit controls the operation of the input unit, the oxygen supply unit, and the discharge unit to control the first temperature measured by the first measurement unit to be 400°C or higher and 800°C or lower, and control the second temperature measured by the second measurement unit to be lower than the first temperature.

[2] The semi-carbide manufacturing device described in [1], in which the difference between the inner radius of the main body and the outer radius of the heating section is 300 mm or less.

[3] Semi-carbide that is mixed with coal and used as fuel for thermal power generation, the semi-carbide having a Hardgrove Crushability Index of 20 or more and 50 or less.

[4] A thermal power generation fuel that is a mixture of the semi-carbide described in [3] and coal.

[5] A thermal power generation fuel according to [4], in which the proportion of the semi-carbide in the mixture is 10% by mass or more and 30% by mass or less.

[6] A power generation method comprising the steps of: mixing the semi-carbide described in [3] with coal to obtain fuel for thermal power generation; and burning the fuel for thermal power generation to generate thermal power.

[7] The power generation method described in [6], in the step of obtaining the thermal power generation fuel, the semi-carbide and the coal are mixed so that the ratio of the semi-carbide in the thermal power generation fuel is 10% by mass or more and 30% by mass or less.

[8] The power generation method according to [6] or [7], wherein the step of obtaining the fuel for thermal power generation includes a step of obtaining a mixture of the semi-carbide and the coal, and a step of pulverizing the mixture.

According to the present invention, it is possible to provide a semi-carbide manufacturing device that can produce semi-carbide using less energy than conventional methods. It is also possible to provide semi-carbide suitable for use as fuel for power generation. It is also possible to provide a thermal power generation fuel that contains such semi-carbide, and a power generation method that uses such a thermal power generation fuel as fuel.

FIG. 1 is a cross-sectional view of a semi-carbide manufacturing apparatus 1 according to an embodiment of the present invention. FIG. 2 is a schematic diagram showing a semi-carbide 100 produced by the production apparatus 1.

The semi-carbide manufacturing device according to this embodiment will be described below with reference to Figures 1 and 2. Note that in all of the following drawings, the dimensions and ratios of each component have been appropriately changed to make the drawings easier to understand.

[Semi-carbide manufacturing equipment]
Fig. 1 is a cross-sectional view of a semi-carbonized material manufacturing apparatus 1 according to this embodiment. As shown in Fig. 1, the manufacturing apparatus 1 has a main body section 10, a heating section 20, a temperature measuring section 30, an oxygen supply section 40, an input section 50, a discharge section, and a control section 90. In the manufacturing apparatus 1, biomass is used as a raw material M, and the biomass is heat-treated to manufacture semi-carbonized material.

As mentioned above, in this specification, "biomass" refers to resources derived from living organisms, excluding fossil resources. Examples of biomass include thinned wood, pruned branches, lumber waste, bamboo, and rice straw.

Biomass also includes "organic waste," which is organic waste. Organic waste includes, for example, food waste, construction waste, shredder dust, livestock waste, sludge, and general waste from households. Such organic waste is generally considered to be worthless, and disposal is costly.

It is preferable that the raw material M is dried in advance before being fed into the manufacturing apparatus 1, and that the moisture content is appropriately adjusted. This is because it is possible to increase the carbonization efficiency and yield. When wood pellets are used as the raw material M, it is preferable that the moisture content of the raw material M fed into the manufacturing apparatus 1 is 5% by mass or more and 20% by mass or less. More preferably, it is 5% by mass or more and 15% by mass or less.

The raw material M may also be crushed or pelletized in advance in a pre-processing step not shown.

The manufacturing device 1 heat-treats the input raw material M to produce semi-carbonized material 100. In the process of producing semi-carbonized material 100 from raw material M, the manufacturing device 1 causes "decomposition and combustion" of raw material M, partial "carbonization" of the solid matter produced by the decomposition and combustion, and "combustion" of the pyrolysis gas produced by the decomposition and combustion.

In this specification, "decomposition combustion" refers to a reaction in which raw material M is partially decomposed and pyrolysis gas G is separated from raw material M.

In this specification, "carbonization" refers to a reaction in which the solid content S generated by decomposition and combustion is further pyrolyzed, increasing the carbonized matter content in the solid content S. In this sense, "semi-carbonization" refers to a reaction in which the solid content S is heat-treated to a state in which the carbonized matter content in the solid content S is higher than that of the raw material M, and there is still room for pyrolysis compared to complete carbonization.

In this specification, "pyrolysis gas" refers to a mixed gas produced by the thermal decomposition of raw material M. Pyrolysis gas G is a mixed gas containing, for example, carbon monoxide, hydrogen, hydrocarbons, sulfur oxides, nitrogen oxides, etc. Pyrolysis gas G is combustible. In the manufacturing apparatus 1, the pyrolysis gas G produced by "decomposition combustion" is "combusted" and consumed. Pyrolysis gas G is combusted to become "exhaust gas."

The manufacturing device 1 is used to heat-treat and semi-carbonize biomass to produce semi-carbonized material 100. Each component of the manufacturing device 1 will be described in order below.

<Main body>
The main body 10 is a cylindrical member extending in the vertical direction and having an internal space 10a. The cross-sectional shape of the main body 10 in a plan view may be a circle whose radius varies depending on the height. The main body 10 may have irregularities on the inner or outer surface of the side wall.

The main body 10 functions as a reaction vessel that contains raw material M in the internal space 10a and heat-treats the raw material M to semi-carbonize it.

The size of the main body 10 may be set based on the predicted amount of raw material M to be processed or the predicted amount of the target product (semi-carbonized material 100) to be produced, depending on the expected operating conditions of the manufacturing device 1. For example, the outer diameter of the main body 10 is 2600 mm, and the inner diameter is 2000 mm. For example, the height of the main body 10 is 5000 mm.

The material constituting the main body 10 can be any material that is typically used for the manufacturing device 1. Examples of such materials include stainless steel.

The main body 10 has an inlet 11, an outlet 12, an air supply port 13a, an air supply port 13b, and an exhaust port 14.

(Inlet)
The inlet 11 is a component for feeding the raw material M into the internal space 10a. The inlet 11 is provided on a side wall of the main body 10. The inlet 11 is connected to an input unit 50 that feeds the raw material M into the internal space 10a. The input unit 50 is not particularly limited as long as it is capable of controlling the amount of raw material M fed per unit time. Examples of the input unit 50 include a screw feeder or a table feeder.

The raw material M is fed into the internal space 10a of the main body 10 through the feed port 11. The raw material M may be fed continuously or intermittently through the feed port 11. The amount of raw material M fed can be controlled according to the state of the reaction in the internal space 10a.

(Exhaust port)
The discharge outlet 12 is a component for discharging to the outside a product produced by processing the raw material M in the internal space 10a, i.e., the semi-carbide 100 produced by the production apparatus 1. The discharge outlet 12 is provided in the lower part of the main body 10. In FIG. 1, the discharge outlet 12 is shown as being provided in the bottom part of the main body 10.

(Air supply port)
The air supply ports 13 are through-holes provided in the side wall of the main body 10 below the input port 11 and above the input port 11. Air (oxygen) from outside the device is supplied to the internal space 10a through the air supply ports 13.

The air supply port 13 includes an air supply port 13a provided below the input port 11 and an air supply port 13b provided above the input port 11. It is preferable that the air supply ports 13a and 13b are each provided discretely around the entire circumference of the side wall of the main body 10.

The air (oxygen) supplied from the air supply port 13a promotes the decomposition and combustion of the raw material M in the internal space 10a near the air supply port 13a. The space in the internal space 10a where the decomposition and combustion of the raw material M is promoted is called the decomposition and combustion zone Z1.

The temperature of the decomposition and combustion zone Z1 is preferably 400°C or higher and 800°C or lower, and more preferably 500°C or higher and 600°C or lower. When the temperature of the decomposition and combustion zone Z1 is within the above range, the decomposition and combustion of the input raw material M is promoted, and volatile matter is easily removed from the raw material M, while carbonization of the surface of the raw material M is less likely to progress. Therefore, when the temperature near the input port 11 is within the above range, volatile matter is easily removed not only from near the surface of the raw material M but also from near the center, which is preferable.

In the decomposition combustion zone Z1, the raw material M is ignited by the ignition unit 25 described below at the beginning of operation. During continuous operation, the raw material M is ignited from the raw material M that is already burning in the decomposition combustion zone Z1. Furthermore, oxygen is supplied to the ignited raw material M from the air supply port 13a. As a result, the raw material M is decomposed and burned in the decomposition combustion zone Z1, generating pyrolysis gas G and solids S.

The solids S produced in the decomposition combustion zone Z1 descend into the internal space 10a as processing in the manufacturing device 1 progresses.

Of the pyrolysis gas G generated in the decomposition combustion zone Z1, the remainder that is not combusted in the decomposition combustion zone Z1 rises in the internal space 10a.

In addition, in the decomposition combustion zone Z1, a portion of the pyrolysis gas G is combusted (primary combustion of the pyrolysis gas G).

The air (oxygen) supplied from the air supply port 13b promotes the "combustion" of the pyrolysis gas G rising from the decomposition combustion zone Z1 in the internal space 10a near the air supply port 13b.

In this specification, the combustion of pyrolysis gas G in the internal space 10a above the inlet 11 is sometimes referred to as "secondary combustion" in contrast to the combustion of pyrolysis gas G in the decomposition combustion zone Z1 (primary combustion). In addition, the space above the internal space 10a where the pyrolysis gas G undergoes secondary combustion is referred to as the secondary combustion zone Z2.

To promote secondary combustion, the temperature near the secondary combustion zone Z2 is preferably 800°C or higher, and more preferably 1000°C or higher. Due to the heat of combustion of the pyrolysis gas G, the temperature of the secondary combustion zone Z2 is higher above the secondary combustion zone Z2 than below it. There is no upper limit to the temperature as long as it does not damage the manufacturing apparatus 1, but the temperature of the secondary combustion zone Z2 is generally 1200°C or lower, and more preferably 1150°C or lower.

In addition, it is preferable to set the residence time of the pyrolysis gas G in the secondary combustion zone Z2 to 2 seconds or more, as this promotes secondary combustion and reduces the generation of dioxins.

(Exhaust port)
The exhaust port 14 is a component for discharging exhaust gas generated by combustion of the pyrolysis gas G from the manufacturing apparatus 1. The exhaust port 14 is provided in the upper part of the main body 10. The exhaust port 14 is provided above the air supply port 13b.

<Heating section>
The heating unit 20 is a cylindrical member with a closed upper end, and is provided below the internal space 10a. An apex 20a of the heating unit 20 is located below the input port 11.

As shown in FIG. 1, the shape of the upper part of the heating unit 20 is preferably conical. The heating unit 20 may have an uneven surface. The heating unit 20 is provided coaxially with the main body unit 10.

The material constituting the heating section 20 can be any material that is commonly used for heating sections. Examples of such materials include stainless steel.

The heating unit 20 is arranged coaxially with the central axis L of the main body unit 10. In addition, the heating unit 20 is spaced apart from the main body unit 10 in the radial direction of the main body unit 10.

At the beginning of operation, the heating section 20 is heated by the ignition section 25, which will be described later. During continuous operation, the heating section 20 is heated by the heat generated by the decomposition and combustion of the raw material M and the combustion of the pyrolysis gas G. As a result of this heating, the heating section 20 stores heat and heats the raw material M by radiation and heat transfer.

The heating section 20 heats the deposition space 10x to a temperature that can be maintained at 200°C or higher and 400°C or lower. This allows the heating section 20 to promote the decomposition, combustion, and carbonization of the raw material M.

The heating unit 20 may have a heat source separate from the heat obtained from the ignition unit 25 and the heat generated by decomposition combustion or combustion.

As described above, the raw material M introduced into the internal space 10a is ignited by the raw material M already burning in the decomposition combustion zone Z1. Also, as described above, in the manufacturing apparatus 1, the heating section 20 is heated by the heat generated by the decomposition combustion of the raw material M and the combustion of the pyrolysis gas G. In this way, in the manufacturing apparatus 1, during continuous operation, the decomposition reaction of the raw material M is caused by using the reaction heat generated in the process of obtaining the target semi-carbonized material 100 from the raw material M, without inputting energy or fuel from the outside. In other words, in the manufacturing apparatus 1, a portion of the raw material M is used as fuel to cause the decomposition reaction of the raw material M.

In the following description, the method of obtaining the heat required for pyrolysis of raw material M by using a portion of raw material M as fuel may be referred to as the "self-combustion type." Because the manufacturing apparatus 1 employs the self-combustion type, it is easy to reduce the operating costs for obtaining semi-carbonized material 100.

The solids S generated in the decomposition combustion zone Z1 are deposited in the deposition space 10x between the main body 10 and the heating section 20. The solids S gradually descend into the deposition space 10x (internal space 10a) and are discharged from the discharge port 12.

The solid matter S is piled up in the upper part of the pile-up space 10x with its surface ignited. Meanwhile, in the decomposition combustion zone Z1, oxygen is consumed by the decomposition combustion, so the pile-up space 10x located below the decomposition combustion zone Z1 is a space lacking in oxygen. The pile-up space 10x also has a temperature distribution in which the higher the area closer to the decomposition combustion zone Z1, the lower the temperature is. The solid matter S piled up in this pile-up space 10x is extinguished as it moves downward through the pile-up space 10x.

The solid content S is heated by the heating unit 20 in the deposition space 10x. This causes the solid content S to undergo thermal decomposition in an oxygen-deficient state, generating thermal decomposition gas G. The solid content S releases the generated thermal decomposition gas G, reducing its mass.

As a result, the reaction of the solid content S ends while leaving behind the carbonizable parts (organic matter), and the solid content S becomes semi-carbonized material 100.

The size of the heating section 20 is set according to the size of the main body section 10. The difference between the inner radius of the main body section 10 and the outer radius of the heating section 20 (the width W of the deposition space 10x) is 300 mm or less, and preferably 200 mm or less. There is no particular limit to the lower limit of the width W, but it is preferably 50 mm or more. More preferably, it is 100 mm or more.

By reducing the width W, unevenness in the transfer of heat from the heating section 20 to the solid content S is reduced, making it possible to obtain homogeneous solid content S.

The reduction in the volume of the accumulation space 10x caused by reducing the width W of the heating section 20 can be compensated for by increasing the height H of the heating section 20. In addition, by increasing the height H, the travel distance of the ignited solid content S in the accumulation space 10x is increased, and the fire can be extinguished reliably.

In FIG. 1, the width W is constant, but the width W may vary depending on the height position. When the width W varies, it is preferable that the width (width W1) above the deposition space 10x is wider than the width (width W2) below the deposition space 10x (W1>W2). As described above, in the deposition space 10x, the thermal decomposition of the solid content S progresses and thermal decomposition gas G is generated. The amount of thermal decomposition gas G generated is greater above the deposition space 10x than below. Therefore, it is preferable that the width W of the deposition space 10x satisfies W1>W2, since the thermal decomposition gas G generated in the deposition space 10x can be easily released from the deposition space 10x.

To make the width W of the deposition space 10x greater than W2, the heating section 20 may have a different diameter depending on the height position. The heating section 20 may be, for example, a truncated cone shape, or may have a shape in which cylinders of different diameters are connected together.

The heating unit 20 may be rotatable around a central axis L. By rotating, the heating unit 20 can agitate the solid content S that accumulates in the gap between the main body 10 and the heating unit 20, allowing it to react uniformly.

The means for rotating the heating unit 20 is not limited, but the shaft 21 and the heating unit 20 may be connected and the shaft 21 may be rotated by a known driving means. The rotation speed may be appropriately adjusted depending on the type, composition, size, shape, etc. of the raw material M.

The heating unit 20 has a turntable 22 at its bottom. The turntable 22 is preferably frustoconical. The turntable 22 is rotatable around a central axis L. The turntable 22 may be rotatable independently of the heating unit 20.

The turntable 22 rotates to supply the product (semi-carbonized material 100) produced by processing the raw material M to the discharge port 12, and discharges it from the internal space 10a to the outside via the discharge port 12. In other words, the turntable 22 corresponds to the "discharge section" in this invention. The turntable 22 can control the discharge speed of the semi-carbonized material 100 by adjusting the rotation speed.

The turntable 22 may be movable up and down, and the distance between the turntable 22 and the main body 10 may be adjusted as appropriate. In this configuration, the gap between the turntable 22 and the main body 10 may be adjusted as appropriate according to the size of the semi-carbide 100.

The means for raising, lowering and rotating the turntable 22 may be any known means.

The heating unit 20 may be removable from the bottom of the main body 10. Inside the manufacturing apparatus 1, clinker may be present, which is mainly composed of dissolved inorganic components such as silica and calcium that have cooled. The clinker may impair the performance of the manufacturing apparatus 1, and therefore needs to be removed periodically. If the heating unit 20 is removable, the work of removing the clinker is easy. A known means may be used to remove the heating unit 20 from the bottom of the main body 10.

<Ignition part>
The ignition unit 25 is a burner provided on the inner wall of the main body 10. The ignition unit 25 heats the heating unit 20 and also has a function of warming the internal space 10a. By heating the heating unit 20 and the internal space 10a before the raw material M is charged, the raw material M can be carbonized efficiently. It is preferable that the internal space 10a is heated to at least 200° C. before the raw material M is charged.

The ignition unit 25 only needs to be able to heat the upper part of the heating unit 20, but is preferably provided at a position where it can heat the area around the apex 20a in particular. The ignition unit 25 is preferably provided at a position higher than the apex 20a of the heating unit 20. The ignition unit 25 is also preferably provided below the input port 11. The ignition unit 25 may be provided at multiple locations, not just one location.

The ignition section 25 is also used to ignite the raw material M in the decomposition combustion zone Z1 at the beginning of operation of the manufacturing apparatus 1.

<Temperature measurement part>
The temperature measuring unit 30 measures the temperature of the internal space 10 a. The temperature measuring unit 30 has a first measuring unit 31 and a second measuring unit 32.

The first measuring unit 31 is located above the apex 20a of the heating unit 20 and below the inlet 11, and measures the temperature of the decomposition combustion zone Z1. The temperature measured by the first measuring unit 31 is defined as the first temperature T1.

The second measuring unit 32 is provided below the position of the apex 20a of the heating unit 20 and measures the temperature of the deposition space 10x. The temperature measured by the second measuring unit 32 is referred to as the second temperature T2.

In FIG. 1, the temperature measuring unit 30 is provided on the inner wall of the main body 10. In the manufacturing device 1, each component is feedback-controlled by the control unit 90 (described later) based on the temperature measured by the temperature measuring unit 30.

The manufacturing apparatus 1 is a self-combusting type, and it is necessary to ignite the raw material M in the decomposition combustion zone Z1. On the other hand, in the manufacturing apparatus 1, it is necessary to control the reaction so that the raw material M is not completely carbonized, or so that an imbalance occurs in which the surface of the raw material M is excessively carbonized and the thermal decomposition inside the raw material M does not progress. Therefore, in the manufacturing apparatus 1, the temperature of the decomposition combustion zone Z1 is controlled to be 400°C or higher and 800°C or lower.

In addition, in the manufacturing apparatus 1, the raw material M is controlled so as not to be completely carbonized in the deposition space 10x. Therefore, in the manufacturing apparatus 1, the temperature of the deposition space 10x is set to a temperature lower than that of the decomposition and combustion zone Z1, and the solid content S is pyrolyzed at a temperature lower than that of the decomposition and combustion zone Z1. As an example, when the raw material M is woody biomass, it is preferable to control the reaction of the raw material M so that moisture is removed from the raw material M and a part of the hemicellulose and cellulose that constitute the woody biomass is pyrolyzed. In such a case, the temperature of the deposition space 10x is preferably controlled to about 200°C to 400°C.

The main components of woody biomass are cellulose, hemicellulose, and lignin. The decomposition temperatures of these are approximately 240°C (cellulose), approximately 180°C (hemicellulose), and approximately 420°C (lignin), respectively.

The temperature measurement unit 30 can be a commonly known temperature sensor.

In FIG. 1, only one second measuring unit 32 is shown, but multiple second measuring units 32 may be provided. In that case, for example, the second measuring units 32 may be provided at different height positions in the deposition space 10x to measure temperatures at multiple heights.

In the deposition space 10x, the temperature is higher at the top and lower at the bottom. Therefore, when measuring the temperature of the deposition space 10x and feedback controlling each component, rather than measuring and controlling the temperature at one point in the deposition space 10x, control based on the temperatures at multiple points is possible, making it possible to control based on more detailed information.

<Oxygen supply unit>
The oxygen supply unit 40 is a blowing means provided in the air supply port 13. The oxygen supply unit 40 has a fan 41 and a cover 42 that covers the outer wall surface of the main body 10 at the position where the air supply port 13 is provided. An air outlet 41a of the fan 41 is connected to the air supply port 13 via a space covered by the cover 42.

The oxygen supply unit 40 controls the amount of air (oxygen) supplied to the internal space 10a. That is, the oxygen supply unit 40a provided in the air supply port 13a controls the amount of air (oxygen) supplied to the decomposition combustion zone Z1. Also, the oxygen supply unit 40b provided in the air supply port 13b controls the amount of air (oxygen) supplied to the decomposition combustion zone Z1.

By independently controlling each of these oxygen supply units 40, the state of combustion of the raw material M and the reaction of the solid content S in the internal space 10a can be controlled.

<Control Unit>
The control unit 90 controls each component so that the temperatures of the decomposition combustion zone Z1 and the deposition space 10x become predetermined reaction temperatures based on the temperature measured by the temperature measurement unit 30. Specifically, the control unit 90 controls the operation of at least one of the oxygen supply unit 40, the input unit 50, and the turntable 22 to control the first temperature T1 measured by the first measurement unit 31 to be 400° C. or higher and 800° C. or lower.

It is preferable that the control unit 90 controls the first temperature T1 to 500°C or higher. It is also preferable that the control unit 90 controls the first temperature T1 to 600°C or lower. The upper and lower limit values of the first temperature T1 can be combined in any manner.

The control unit 90 also controls the operation of at least one of the oxygen supply unit 40, the input unit 50, and the turntable 22 to control the second temperature T2 measured by the second measurement unit 32 to a temperature lower than the first temperature T1.

The control unit 90 controls the operation of the oxygen supply unit 40 and controls the amount of air (oxygen) supplied to the internal space 10a per unit time. This controls the reaction heat generated in each part of the internal space 10a, particularly in the decomposition combustion zone Z1, and mainly adjusts the temperature of the decomposition combustion zone Z1.

The control unit 90 controls the feed rate of the raw material M in the feed unit 50 (the amount of raw material M fed per unit time). This controls the reaction in the decomposition combustion zone Z1, and mainly adjusts the temperature of the decomposition combustion zone Z1.

The control unit 90 controls the rotation speed of the turntable 22 (discharge unit) and changes the discharge speed of the semi-carbonized material 100 from the internal space 10a (the amount of semi-carbonized material 100 discharged per unit time). This makes it possible to adjust the temperature of the deposition space 10x.

The manufacturing apparatus 1 can control the temperature of the decomposition combustion zone Z1 (first temperature T1) and the temperature of the deposition space 10x (second temperature T2) by controlling these with the control unit 90. This allows the manufacturing apparatus 1 to control the reaction state of the solid content S and obtain the desired semi-carbonized material 100.

If the control unit 90 is capable of the above-mentioned control, it may be configured to control the operation of at least one of the oxygen supply unit 40, the input unit 50, and the turntable 22 according to predetermined reference values of the measured temperatures (first temperature T1, second temperature T2) by sequence control. Such a control unit 90 is called a PLC (Programmable Logic Controller). Such a control unit 90 enables automatic control of each component according to the measured temperature.

The control unit 90 may also be configured so that an operator inputs the control conditions for each component based on the measured temperatures (first temperature T1, second temperature T2).

Such a manufacturing apparatus 1 operates as follows.
First, at the beginning of the operation of the manufacturing apparatus 1, the heating section 20 is heated by the ignition section 25. The raw material M fed into the internal space 10a by the feeding section 50 is also ignited by the ignition section 25. As a result, the decomposition and combustion zone Z1 is heated, and the raw material M begins to decompose and burn. The heat generated by the decomposition and combustion of the raw material M is used as a heat source for heating the decomposition and combustion zone Z1.

In addition, when the manufacturing apparatus 1 is in continuous operation, raw material M further added to the decomposition combustion zone Z1 is not ignited by the ignition unit 25, but is ignited by the combustion of raw material M burning in the decomposition combustion zone Z1.

In the decomposition and combustion zone Z1, the raw material M is ignited and decomposed and burned, and is heated to the center of the raw material M.

The solid matter S generated by decomposition and combustion moves in an ignited state from the decomposition and combustion zone Z1 to the accumulation space 10x and accumulates. In the accumulation space 10x, the solid matter S is heated by the heating section 20, and decomposition and combustion proceeds. The solid matter S decomposes and burns as it descends through the accumulation space 10x, releasing pyrolysis gas G. The generated pyrolysis gas G rises from the accumulation space 10x to the decomposition and combustion zone Z1, where it is partially combusted. The heat generated by the decomposition and combustion of the pyrolysis gas G is used as a heat source to heat the decomposition and combustion zone Z1.

In the decomposition combustion zone Z1, oxygen is consumed by decomposition combustion. Therefore, oxygen is not easily supplied from the oxygen supply unit 40a located above the decomposition combustion zone Z1 to the deposition space 10x below the decomposition combustion zone Z1. As a result, the deposition space 10x is a space with a shortage of oxygen toward the bottom. Also, the deposition space 10x has a temperature distribution in which the temperature is higher toward the top, closer to the decomposition combustion zone Z1, and is relatively lower toward the bottom than toward the top.

The solid matter S that accumulates in such a space is extinguished and thermally decomposed as it moves downward through the accumulation space 10x. As a result, the solid matter S becomes semi-carbonized matter 100.

The semi-carbide material 100 moves as the turntable 22 rotates and is discharged from the discharge port 12.

During continuous operation of the manufacturing apparatus 1, the decomposition and combustion of the raw material M in the decomposition and combustion zone Z1 is controlled by the temperature of the decomposition and combustion zone Z1. The temperature of the decomposition and combustion zone Z1 is controlled by the feed rate of the raw material M through the feed section 50 and the amount of air supplied by the oxygen supply section 40a.

The decomposition and combustion of the solid content S in the deposition space 10x is controlled by the temperature of the deposition space 10x. The temperature of the deposition space 10x is controlled by the supply rate of the solid content S supplied to the deposition space 10x (i.e., the input rate of the raw material M by the input section 50) and the discharge rate of the semi-carbonized material 100 by the turntable 22.

In the manufacturing apparatus 1, the temperature of the decomposition combustion zone Z1 and the temperature of the deposition space 10x are controlled as described above, so that the semi-carbide 100 can be suitably manufactured.

In the deposition space 10x, the solid content S is pyrolyzed in a low-temperature atmosphere of about 200°C to 400°C to proceed with carbonization. Normally, when the solid content S is pyrolyzed at such temperatures, soot and tar are generated as decomposition products. These decomposition products can cause blockages in the piping, so with conventional equipment, carbonization in the above-mentioned low-temperature atmosphere was difficult.

In response to this, the manufacturing apparatus 1 employs a spontaneous combustion system, and the pyrolysis gas G is burned in the decomposition combustion zone Z1 and the secondary combustion zone Z2. Therefore, the soot and tar are burned and consumed in the decomposition combustion zone Z1 and the secondary combustion zone Z2. This makes it possible to prevent the clogging of piping by decomposition products in the manufacturing apparatus 1.

In this type of manufacturing apparatus 1, most of the reaction heat required to obtain the semi-carbide 100 is generated by using the heat generated by the combustion of the raw material M and the combustion of the pyrolysis gas. Therefore, the energy required for the reaction can be reduced compared to conventional rotary kiln-type manufacturing apparatuses.

Therefore, the manufacturing device 1 configured as described above is a semi-carbide manufacturing device that can produce semi-carbide with less energy than conventional methods.

[Semi-carbide]
Fig. 2 is a schematic diagram and a schematic cross-sectional view showing an example of the semi-carbide 100 produced by the production apparatus 1. In Fig. 2, the cross-sectional shape of the semi-carbide 100 is circular for ease of explanation, but is not limited thereto. The shape of the semi-carbide 100 may be various shapes based on the shape of the raw material M.

As shown in FIG. 2, the semi-carbonized material 100 has a core 100a that has been pyrolyzed more than the raw material but still contains carbonizable organic matter, and a shell 100b that is mainly composed of charcoal. The semi-carbonized material 100 of this embodiment is manufactured by the manufacturing apparatus 1 described above. During the manufacturing process, the surface of the raw material ignites once and then the fire is extinguished, so that the semi-carbonized material 100 is structured such that the surface is more carbonized and the interior is where most of the organic matter remains.

The shell 100b may completely cover the core 100a. Alternatively, the shell 100b may cover only a portion of the core 100a, with the remainder of the core 100a exposed from the shell 100b.

Because the shell 100b is a carbide, the semi-carbide 100 repels water and absorbs moisture less easily than the raw material M. Therefore, the semi-carbide 100 is easy to store as fuel and does not absorb moisture that inhibits combustion. Therefore, even if left outdoors, the semi-carbide 100 is less likely to absorb moisture from rain or frost than the raw material M, making it easier to handle.

For example, when wood pellets made from solidified sawdust are used as raw material M, if raw material M is left as is and absorbs moisture, it may expand and collapse, returning to sawdust. On the other hand, semi-carbonized material 100 obtained from wood pellets is less likely to absorb moisture, and deformation can be suppressed.

In FIG. 2, the semi-carbonized material 100 is shown as having a configuration in which the core 100a and the shell 100b are clearly separated, but this is not limited thereto. The semi-carbonized material 100 may have only the core 100a without the shell 100b. In this case, the semi-carbonized material may be uniformly semi-carbonized from the surface toward the center. Alternatively, the semi-carbonized material 100 may be in a state in which the carbonization process is more advanced toward the surface than toward the center, with a gradient in the carbonization state from the center toward the surface.

The semi-carbonized material 100 has a reduced mass and improved energy density compared to the raw material. For example, when raw material M is wood chips, the energy density of raw material M is approximately 10 MJ/kg, and when raw material M is wood pellets, the energy density of raw material M is approximately 15 MJ/kg. On the other hand, when these wood raw materials are heat-treated in the above-mentioned manufacturing device 1 and the mass of the raw material is reduced by 20-30%, the energy density of the resulting semi-carbonized material 100 increases to 19-23 MJ/kg.

The mass reduction rate of the semi-carbide 100 relative to the raw material M may be set appropriately based on the material of the raw material M and the target energy density of the semi-carbide 100.

Semi-carbide 100 has a Hardgrove Grindability Index (HGI) of 20 or more and 50 or less. HGI can be measured in accordance with JIS M 8801.

The semi-carbonized material 100 has a shell 100b made of carbonized material and has less moisture and oil than the raw material, so it is harder and more brittle than raw materials (e.g., woody biomass) whose surfaces are not carbonized. Such semi-carbonized material 100 can be pulverized using a commonly known mill.

Typically, the HGI of coal used as fuel for thermal power generation is around 40 to 70. In coal-fired power generation, in order to burn the coal efficiently, the coal is milled to around 100 μm before being fed into the boiler. As described above, when semi-carbide 100 is mixed with coal to be used as fuel for thermal power generation, semi-carbide 100 is required to be pulverizable in the same way as coal.

The semi-carbide 100 of this embodiment has an HGI of 20 or more and 50 or less. Semi-carbide 100 having such an HGI can be pulverized using existing equipment for pulverizing coal. Therefore, a mixture of semi-carbide 100 and coal can be pulverized in a commonly used coal pulverizing mill in the same manner as coal. Due to these properties, semi-carbide 100 can be pulverized using existing equipment effectively, making it suitable for use as fuel for thermal power generation.

The semi-carbide 100 configured as described above is suitable as fuel for power generation.

[Fuel for thermal power generation]
The thermal power generation fuel of this embodiment is a mixture of the semi-carbide 100 and coal. The thermal power generation fuel has a ratio of the semi-carbide 100 in the mixture of 10 mass % to 30 mass %.

[Power generation method]
The power generation method of the present embodiment includes a step of mixing the semi-carbonized material 100 with coal to obtain the fuel for thermal power generation, and a step of burning the fuel for thermal power generation to generate thermal power.

In the process of obtaining fuel for thermal power generation, the ratio of semi-carbide 100 in the obtained fuel for thermal power generation may be set to 10% by mass or more and 30% by mass or less, and the semi-carbide 100 may be mixed with coal.

The process for obtaining fuel for thermal power generation may include a process for obtaining a mixture of semi-carburized material 100 and coal, and a process for crushing the mixture.

The thermal power generation fuel and power generation method configured as described above can reduce carbon dioxide emissions derived from fossil fuels and bring us closer to carbon neutrality.

The above describes preferred embodiments of the present invention with reference to the attached drawings, but the present invention is not limited to these examples. The shapes and combinations of the components shown in the above examples are merely examples, and various modifications can be made based on the design, specifications, etc., without departing from the spirit of the present invention.

DESCRIPTION OF SYMBOLS 1... Manufacturing device, 10... Main body part, 10a... Internal space, 12... Discharge port, 20... Heating part, 20a... Apex, 21... Shaft, 30... Ignition part, 40, 40a, 40b... Oxygen supply part, 50... Temperature measurement part, 90... Control part, 100... Half carbide, L... Central axis, M... Raw material

Claims (3)

A cylindrical main body portion extending in a vertical direction and having an internal space for heat-treating a raw material;
A heating unit for heating the raw material;
A temperature measuring unit for measuring the temperature of the internal space;
an oxygen supply unit that supplies oxygen to the internal space;
An input section for inputting the raw material into the internal space;
A discharge section that discharges a product generated by processing the raw material from the internal space;
A control unit that controls the operation of the oxygen supply unit, the input unit, and the discharge unit,
The main body has an inlet for introducing the raw material above the heating unit and an outlet for discharging the product below the internal space,
The feeding unit is connected to the feeding port and controls a feeding speed of the raw material;
The discharge unit controls a discharge rate of the product discharged from the discharge port,
The heating unit is a cylindrical member having a closed upper end and is provided below the internal space,
The main body portion and the heating portion are arranged coaxially with a central axis of the main body portion and are spaced apart from each other in a radial direction of the main body portion,
The temperature measurement unit includes a first measurement unit provided above the heating unit and below the input port;
A second measurement unit is provided below the apex position of the heating unit,
The control unit controls the operation of the input unit, the oxygen supply unit, and the discharge unit to control the first temperature measured by the first measurement unit to be greater than or equal to 400°C and less than or equal to 800°C, and to control the second temperature measured by the second measurement unit to be a temperature lower than the first temperature. The semi-carbide manufacturing device according to claim 1, wherein the difference between the inner radius of the main body and the outer radius of the heating section is 300 mm or less. The apparatus for manufacturing semi-carbide according to claim 1 or 2, wherein the control unit controls the second temperature to be in the range of 200°C to 400°C.

Images