JP2024008081A - Cooling structure, screw feeder, and cooling method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide: a cooling structure capable of efficiently cooling the tip of a screw feeder with a cooling medium; a screw feeder; and a cooling method.

SOLUTION: There is provided a cooling structure 20 of a screw feeder feeding biomass fuel into a gasification furnace, comprising an outer jacket 21 demarcating a space therein with a closed tip 21c positioned inside the furnace, and an inner jacket 22 disposed in the space of the outer jacket 21 to demarcate a forward path 23 of a cooling medium W therein and a return path 24 of the cooling medium W between itself and the outer jacket 21, with an ejection port 22a being formed on a position opposing the closed tip 21c of the outer jacket 21 so that the cooling medium W flowing through the forward path 23 is ejected therefrom.

SELECTED DRAWING: Figure 3

COPYRIGHT: (C)2024,JPO&INPIT

Description

The present disclosure relates to a cooling structure, a screw feeder, and a cooling method.

For example, in a gasification furnace that uses biomass fuel, a screw feeder may be used when feeding fuel into the furnace (see Patent Document 1).

Since the screw feeder is connected to the gasifier and its tip faces into the high-temperature furnace, the screw feeder may be heated to a high temperature by heat conduction or radiation from inside the furnace. Therefore, by providing a cooling structure, the entire screw feeder may be cooled.

JP2016-190888A

The distal end portion of the screw feeder tends to become hotter than other portions (for example, the proximal end portion of the screw feeder). For example, when the temperature inside the furnace is around 1000 degrees Celsius, the temperature at the tip of the screw feeder can reach several hundred degrees Celsius, causing thermal stress due to the temperature gradient, which can lead to damage to the screw feeder depending on the situation. There is sex.

Furthermore, although the gasification gas flowing through the furnace contains water vapor, if the screw feeder is excessively cooled, the water vapor that has flowed into the screw feeder from inside the furnace may condense. In this case, the biomass fuel becomes wet due to the condensed water, reducing its fluidity and potentially clogging the screw feeder.
On the other hand, if the screw feeder is insufficiently cooled, the temperature of the screw feeder becomes higher than the softening temperature of lignin contained in biomass fuel (for example, wood-based fuel), and the lignin may soften. In this case, the biomass fuel adheres to the screw feeder due to the softened lignin, which may reduce the fluidity of the biomass fuel and cause the screw feeder to become clogged.

The present disclosure has been made in view of the above circumstances, and the first object is to provide a cooling structure, a screw feeder, and a cooling method that can cool the tip of a screw feeder with a cooling medium. do.
A second object of the present invention is to provide a cooling structure, a screw feeder, and a cooling method that can maintain a screw feeder at an appropriate temperature.

In order to solve the above problems, the cooling structure, screw feeder, and cooling method of the present disclosure employ the following means.
That is, a cooling structure according to one aspect of the present disclosure is a cooling structure for a screw feeder that supplies biomass fuel into the furnace of a gasifier, in which a space is defined inside and a closed end portion is located inside the furnace. and an outer jacket located in the outer jacket, which is provided in the space of the outer jacket, defines an outgoing path for the cooling medium therein, and defines a return path for the cooling medium between the outer jacket and the cooling medium flowing through the outgoing path. The apparatus further includes an inner jacket formed at a position facing the closed end portion of the outer jacket from which the ejection port is ejected.

Further, a screw feeder according to an aspect of the present disclosure includes the above cooling structure and a screw, and the outer jacket of the cooling structure is a casing that accommodates the screw.

Further, a cooling method according to an aspect of the present disclosure is a cooling method using the above-described cooling structure, in which a cooling medium is jetted out from the jetting port to the closed end portion of the outer jacket. make it collide.

According to the present disclosure, firstly, the tip of the screw feeder can be efficiently cooled with a cooling medium. Second, the screw feeder can be kept at an appropriate temperature.

FIG. 1 is a schematic configuration diagram of a screw feeder and a gasifier to which the screw feeder is connected according to an embodiment of the present disclosure. FIG. 2 is a longitudinal cross-sectional view of a screw according to an embodiment of the present disclosure. FIG. 1 is a longitudinal cross-sectional view of a cooling structure according to an embodiment of the present disclosure. 4 is a longitudinal cross-sectional view taken along cutting line V shown in FIG. 3. FIG. FIG. 3 is a graph diagram showing the relationship between the flow velocity of a cooling medium flowing in an outgoing path and pressure loss. FIG. 3 is a vertical cross-sectional view showing a divided structure of the outer jacket. FIG. 3 is a graph showing the relationship between the ratio of the position from the tip to the inner diameter of the outer jacket and thermal stress. 7 is a longitudinal cross-sectional view of a cooling structure according to modification example 1. FIG. 9 is a longitudinal cross-sectional view taken along cutting line IX shown in FIG. 8. FIG. 7 is a longitudinal cross-sectional view of a cooling structure according to Modification 1. FIG. 11 is a longitudinal cross-sectional view along cutting line XI shown in FIG. 10. FIG.

Hereinafter, a cooling structure, a screw feeder, and a cooling method according to an embodiment of the present disclosure will be described with reference to the drawings.

[About the screw feeder overview]
As shown in FIG. 1, the screw feeder 1 is a device that supplies fuel into the gasifier 50.

The gasification furnace 50 is a facility that generates synthesis gas G from fuel in a furnace under a high-temperature environment of about 500° C. to 1250° C., for example. The generated synthesis gas G is purified, for example, in a gas purification facility (not shown), and then supplied to a liquefaction facility (not shown) to be synthesized as biojet fuel.
As the fuel, biomass fuels containing tar components such as lignin (for example, woody biomass fuels and plant biomass fuels) are used.

As shown in FIGS. 1 and 2, the screw feeder 1 includes a screw 11 and a cooling structure 20 serving as a casing that accommodates the screw 11.

The screw 11 is a part that moves fuel supplied from the fuel supply pipe 32 inside the casing.
The screw 11 has a rotating shaft 11a and a blade 11b attached to wrap around the rotating shaft 11a, and extends along the direction of the rotating axis X.

The rotating shaft 11a is pivotally supported by a bearing 12, and is configured to rotate around a rotation axis X by a motor 31 provided outside the casing.
As the rotating shaft 11a rotates, the blades 11b also rotate, whereby the fuel supplied from the fuel supply pipe 32 moves inside the casing and is supplied into the gasifier 50.

As described above, the cooling structure 20 is a part that functions as a casing that accommodates the screw 11.
Further, inside the cooling structure 20, a flow path (outward path 23 and return path 24) through which the cooling medium W flows is defined, and the temperature-adjusted cooling medium W flows through the flow path to feed the screw feeder 1. is designed to maintain an appropriate temperature. As the cooling medium W, water/hot water is exemplified.

As shown in FIG. 1, the cooling structure 20 is connected to a supply line L1 and a discharge line L2 through which a cooling medium W flows.
The cooling structure 20 constitutes one circulation path together with the supply line L1 and the discharge line L2.

The circulation path is configured to start from the circulation pump 34 (flow rate adjustment section) and return to the circulation pump 34 via the supply line L1 provided with the temperature adjustment section 35, the cooling structure 20, and the discharge line L2. It is a closed path.

The temperature adjustment unit 35 is a device that adjusts (heats/cools) the temperature of the cooling medium W that flows through the supply line L1 and is supplied to the cooling structure 20.
The temperature adjustment unit 35 includes, for example, a heat exchanger 35a and a heating/cooling device 35b, and the heat exchanger 35a performs heat exchange between the heat/cold generated in the heating/cooling device 35b and the cooling medium W. is configured to take place.
Note that the temperature adjustment section 35 may have any configuration as long as it can adjust the temperature of the cooling medium W, and is not limited to the above configuration.

As shown in FIG. 2, the screw feeder 1 has its tip end inserted through the furnace wall of the gasifier 50. Specifically, the tip end portion is inserted into a furnace wall including a refractory material 51 and a gasifier outer wall 52 attached to the outer surface of the refractory material 51.
The screw feeder 1 inserted through the furnace wall is attached to the furnace wall via a mounting seat 53 and a heat insulating material 54.

The tip of the screw feeder 1 attached to the furnace wall faces into the furnace.
Here, the tip of the screw feeder 1 is the tip of the cooling structure 20 as a casing, specifically, the closing portion 21c of the outer jacket 21, which will be described later.

[About the cooling structure]
As shown in FIGS. 3 and 4, the cooling structure 20 of the screw feeder 1 includes an outer jacket 21 and an inner jacket 22.
In addition, in FIGS. 3 and 4, illustration of the screw 11, the mounting seat 53, the heat insulating material 54, and the furnace wall (the refractory material 51 and the gasifier outer wall 52) is omitted for simple explanation.

The outer jacket 21 has a cylindrical outer tube 21a and an inner tube 21b whose center axis is the rotation axis X, and a closed portion 21c that connects the tip of the outer tube 21a and the tip of the inner tube 21b. It is said to be a double tube with a bottom.
The outer jacket 21 is made of metal such as stainless steel or carbon steel.

The screw 11 is housed in a space defined by the inner circumferential surface of the outer jacket 21 (in other words, the inner circumferential surface of the inner tube 21b) (see FIG. 2).
A heat insulating material 54 is provided on the outer peripheral surface of the outer jacket 21 (in other words, the outer peripheral surface of the outer tube 21a) (see FIG. 2).

An inner jacket 22 is provided in a space defined by the inner circumferential surface of the outer tube 21a, the outer circumferential surface of the inner tube 21b, and the inner surface of the closing portion 21c.

The inner jacket 22 is, for example, a tube extending in a direction parallel to the rotation axis X (center axis). A spout 22a is formed at the tip of the tubular inner jacket 22.
The spout 22a faces the inner surface of the closing portion 21c at a position spaced apart from the closing portion 21c of the outer jacket 21 by a predetermined distance (for example, equal to or larger than the hole diameter of the spout 22a).
The inner jacket 22 is made of metal such as stainless steel or carbon steel.

As shown in FIG. 4, a plurality of inner jackets 22 are provided at equal angular intervals around the rotation axis X (center axis). In the case of FIG. 4, twelve tubular inner jackets 22 are provided.
Note that the inner jacket 22 can have the above-mentioned configuration as long as it can define an outgoing path 23 through which the cooling medium W flows therein and a return path 24 through which the cooling medium W flows between the inner jacket 22 and the outer jacket 21. but not limited to.

As shown in FIGS. 3 and 4, the inside (inside) of the tubular inner jacket 22 is an outgoing path 23 through which the cooling medium W flows toward the tip side (toward the gasifier 50 side).
Furthermore, the space defined by the outer jacket 21 and the inner jacket 22, specifically, the inner circumferential surface of the outer tube 21a, the outer circumferential surface of the inner tube 21b, the inner surface of the closing part 21c, and the outer circumferential surface of the inner jacket 22. The space formed is a return path 24 through which the cooling medium W flows toward the base end side (motor 31 side).
At this time, the outgoing path 23 communicates with the incoming path 24 via the jet port 22a formed at the tip of the inner jacket 22.

A supply line L1 for the cooling medium W is connected to an upstream portion (not shown) of the outgoing path 23. Thereby, the cooling medium W is supplied to the outgoing path 23 from the supply line L1.
Further, a discharge line L2 for the cooling medium W is connected to a downstream portion (not shown) of the return path 24. Thereby, the cooling medium W is discharged from the return path 24 to the discharge line L2.

[About the flow of cooling medium]
The cooling medium W flows as follows.
As shown in FIGS. 1 and 3, the cooling medium W whose pressure has been increased by the circulation pump 34 flows into the outgoing path 23 of the cooling structure 20 through the supply line L1.
At this time, the temperature of the cooling medium W is adjusted to an appropriate temperature by the temperature adjustment section 35. A specific temperature management method will be described later.

The cooling medium W flowing into the outgoing path 23 from the supply line L1 flows toward the tip side (right side in FIG. 3) and is ejected from the ejection port 22a formed at the tip of the inner jacket 22.

The cooling medium W ejected from the ejection port 22 a collides with the inner surface of the closed portion 21 c of the outer jacket 21 .
At this time, the closing portion 21c located at the tip of the cooling structure 20 faces the inside of the furnace through which the synthesis gas G flows, and is the portion of the casing (cooling structure 20) that has the highest temperature.
By causing a jet of the cooling medium W to collide with such a blockage 21c, the blockage 21c and its vicinity can be cooled (impingement jet cooling).
Note that the collision of the jets is not essential, and it is sufficient that the closed portion 21c and its vicinity are cooled by the cooling medium W. However, by using collision jet cooling, the blocking portion 21c and its vicinity can be efficiently cooled.

The cooling medium W that has collided with the closing portion 21c changes its direction so as to turn back along the inner surface of the closing portion 21c, and flows into the return path 24.

The coolant W flowing into the return path 24 flows toward the base end (left side in FIG. 3), is discharged from the return path 24 to the discharge line L2, and returns to the circulation pump 34.
At this time, while the cooling medium W flows through the return path 24, the main portion of the outer jacket 21 is maintained at a predetermined temperature by the cooling medium W. A specific temperature management method will be described later.

Here, the "main portion of the outer jacket 21" is, for example, the proximal portion of the outer jacket 21 excluding the distal portion of the outer jacket 21 including the closing portion 21c facing the inside of the furnace. However, the "main portion of the outer jacket 21" does not include the outer peripheral surface of the outer jacket 21.
As a specific example, the main part of the outer jacket 21 is a portion of the outer jacket 21 that is 0.05 d or more to 0.1 d or more away from the tip of the outer jacket 21, where the inner diameter of the outer jacket 21 is d. In other words, the portion within 0.05 d to 0.1 d from the tip of the outer jacket 21 becomes the portion on the tip side of the outer jacket 21.

Note that the length of the main portion of the outer jacket 21 that is subject to temperature control is sufficiently larger (for example, 4 times or more) than the length of the distal end portion of the outer jacket 21 that is not subject to temperature control.
Here, the "length dimension" is a dimension along the rotation axis X (center axis).

[About temperature management]
The temperature of the cooling medium W flowing into the outgoing path 23 of the cooling structure 20 is adjusted by a temperature adjustment section 35.
Specifically, the temperature of the cooling medium W is adjusted to a temperature such that the metal temperature of the main portion of the outer jacket 21 maintained by the cooling medium W is 80° C. or higher and 100° C. or lower.

As shown in FIG. 1, the cooling structure 20 is provided with a temperature sensor 33 so as to be able to obtain the temperature at a desired location. Although one temperature sensor 33 is shown in FIG. 1 for convenience, the number of temperature sensors 33 may be plural.
The temperature sensor 33 is configured to be able to communicate with the control unit 36. The means of communication may be wired or wireless.

The control unit 36 calculates the metal temperature of the main portion of the outer jacket 21 based on information from the temperature sensor 33. Then, the control unit 36 controls the temperature of the cooling medium W by heating/cooling the cooling medium W using the temperature adjustment unit 35 so that the metal temperature of the main portion of the outer jacket 21 is 80° C. or higher and 100° C. or lower. are doing.

The reason why the metal temperature is set to 80° C. or higher is as follows.
The water vapor concentration in the synthesis gas G in the gasifier 50 is 40 vol% to 80 vol%. Further, the pressure inside the furnace is approximately atmospheric pressure. From these, the condensation temperature relative to the partial pressure of water vapor is approximately 77°C to 94°C.
Therefore, in consideration of these average temperatures, it is preferable to maintain the metal temperature of the main portion of the outer jacket 21 that comes into contact with the syngas G containing water vapor at 80° C. or higher.

The reason why the metal temperature is set to 100° C. or lower is as follows.
Lignin contained in biomass fuel can soften at about 130°C, and the presence of moisture further reduces the softening temperature. For example, the water content contained in wood-based biomass fuel is about 10 wt%. From these results, the softening temperature of lignin is expected to exceed at least 100°C.
Therefore, it is preferable to maintain the metal temperature of the main portion of the outer jacket 21 that comes into contact with the biomass fuel at 100° C. or lower.

Furthermore, even if the metal temperature of the tip side portion (not the main portion) of the outer jacket 21 exceeds 100°C and the lignin softens and biomass fuel adheres, the extent of the adhesion will be limited to the outer jacket near the inside of the furnace. Since the attached biomass fuel is limited to the tip side of the screw 21, the attached biomass fuel is easily pushed out into the furnace by the screw 11.
Therefore, the main portion of the outer jacket 21 may be the only portion where the metal temperature should be kept below 100°C. Note that, of course, the metal temperature of the tip side portion may be maintained at 100° C. or lower.

[About flow rate management]
The flow rate of the cooling medium W flowing inside (inside) the inner jacket 22, that is, through the outgoing path 23, is adjusted, for example, by changing the rotation speed of the circulation pump 34. Note that it may be adjusted by a control valve provided downstream of the circulation pump 34.
Specifically, the flow velocity is adjusted to be 1 m/s or more and 4 m/s or less.

The cooling structure 20 is provided with a sensor (not shown) for measuring the flow velocity of the cooling medium W flowing through the outgoing path 23. The sensor may be, for example, a current meter that directly measures the flow rate or a flow meter that measures the flow rate of the cooling medium W. When the sensor is a flowmeter, the flow velocity can be indirectly measured using the known flow area of the outgoing path 23 and the measured flow rate of the cooling medium W.
The sensor is configured to be able to communicate with the control unit 36. The means of communication may be wired or wireless.

The control unit 36 calculates the flow velocity of the cooling medium W flowing through the outgoing path 23 based on information from the sensor. The control unit 36 manages the flow rate of the cooling medium W by the circulation pump 34.

The reason why the flow velocity is set to 1 m/s or more is as follows.
For example, when the inner diameter of the inner jacket 22 is 0.002 m to 0.005 m, the cooling medium can be uniformly flowed to each inner jacket 22 by setting the flow velocity to 1 m/s. If the flow velocity is lower than 1 m/s, there is a risk that the pressure loss will be too small and the cooling medium will not flow evenly to each inner jacket 22. Therefore, it is preferable that the flow velocity of the cooling medium W is set to 1 m/s or more so that an appropriate pressure loss occurs.

The reason why the flow velocity is set to 4 m/s or less is as follows.
For example, when the inner diameter of the inner jacket 22 is 0.002 m to 0.005 m, the inventor has found that as shown in FIG. 5, the pressure loss rapidly increases near the flow rate of 4 m/s. Therefore, it is preferable that the flow velocity of the cooling medium W is 4 m/s or less.

[About the welded part of the outer jacket]
As shown in FIGS. 3 and 6, the outer jacket 21 may have a divided structure.
Specifically, the welded portion 21w may be formed by dividing the outer jacket 21 into a tip side portion 21t and a main body portion 21m, and joining them by butt welding.
Thereby, the position of the inner jacket 22 and the main body portion 21m can be adjusted while visually checking, so that a highly accurate cooling structure 20 can be manufactured easily.
Furthermore, the main body portion 21m may be divided into an outer tube 21a and an inner tube 21b. As a result, the positions of the outer tube 21a and the inner tube 21b can also be adjusted, so that a return path 24 with high precision can be easily formed.

The tip side portion 21t is a portion on the tip side of the outer jacket 21 that includes the closing portion 21c facing the inside of the furnace. The main body portion 21m is a proximal portion of the outer jacket 21 excluding the distal end portion 21t.
The length L of the tip side portion 21t is the distance from the tip of the outer jacket 21 to the welding portion 21w, and is, for example, 30% or more of the inner diameter d of the outer jacket 21. In other words, L≧0.3×d.

The reason for setting L≧0.3×d is as follows.
The safety factor α when repeated loads are applied is usually 5 or more, so if the allowable tensile stress (tensile strength) of the outer jacket 21 is σ, then the thermal stress acting on the welded part 21w is σ/ It is preferable to keep it within a range of 5 or less.

Here, as shown in FIG. 7, when the horizontal axis is the value (expressed as a percentage) obtained by dividing the position from the tip of the outer jacket 21 by the inner diameter d of the outer jacket 21 and the vertical axis is the thermal stress, the horizontal axis The inventor has found that the thermal stress falls within the range of σ/5 or less at a position of 30%.
Therefore, in order to space the welding portion 21w at least 0.3xd from the tip, it is preferable that L≧0.3xd.

According to this embodiment, the following effects are achieved.
The cooling medium W can be ejected from the ejection port 22a of the inner jacket 22 toward the closed portion 21c of the outer jacket 21.
This allows the cooling medium W to intensively cool the tip of the outer jacket 21, which is easily affected by the temperature inside the furnace. In particular, by causing the jet stream of the cooling medium W to collide with the closed portion 21c of the outer jacket 21, the tip of the outer jacket 21 can be cooled more efficiently. By cooling the tip of the outer jacket 21 in this way, it is possible to reduce the temperature difference (temperature gradient) that occurs in the portion on the tip side, and as a result, it is possible to reduce thermal stress.

Further, the outer jacket 21 can be maintained at an appropriate temperature by the cooling medium W guided from the outgoing path 23 to the incoming path 24 via the jet port 22a.
Thereby, for example, it is possible to suppress condensation of water vapor contained in the synthesis gas G or to suppress softening of lignin contained in the biomass fuel.

Furthermore, when the circulation pump 34 is controlled to adjust the flow rate of the coolant W so that the flow velocity of the coolant W in the outward path 23 is 1 m/s or more and 4 m/s or less, the pressure loss in the outward path 23 is reduced as much as possible. At the same time, a sufficient amount of the cooling medium W can be uniformly ejected from each ejection port 22a.

Furthermore, when the temperature adjustment section 35 is controlled based on the information acquired from the temperature sensor 33 to adjust the temperature of the cooling medium W, the temperature of the outer jacket 21 is maintained at a desired temperature by adjusting the temperature of the cooling medium W. be able to.

In addition, when the temperature of the cooling medium W is adjusted by controlling the temperature adjustment unit 35 so that the temperature of the outer jacket 21 is maintained at a temperature of 80° C. or more and 100° C. or less, the syngas G flowing from inside the furnace contains It is possible to suppress the condensation of water vapor contained in biomass fuels (for example, wood-based fuels) and the softening of lignin contained in biomass fuels (for example, wood-based fuels).
By suppressing condensation of water vapor, it is possible to reduce the possibility that the biomass fuel becomes wet and the screw feeder 1 becomes clogged. Moreover, by suppressing the softening of lignin, it is possible to reduce the possibility that biomass fuel will adhere to lignin and the screw feeder 1 will become clogged.

Further, since the space in which the inner jacket 22 is provided is defined between the outer tube 21a and the inner tube 21b, the inner jacket 22 can be provided inside the double tube structure.

Furthermore, since the outer jacket 21 has a distal end side portion 21t including the closing portion 21c and a main body portion 21m other than the distal end side portion 21t, which are divided along the direction of the rotational axis X, the inner jacket 22 and the main body Since the position with respect to the portion 21m can be adjusted while visually checking, it is possible to easily manufacture the cooling structure 20 with high precision.

Further, if the distal end side portion 21t and the main body portion 21m are joined at a welded portion 21w, and the welded portion 21w is formed at a distance of 30% or more of the inner diameter of the inner tube 21b from the distal end, a large temperature difference ( The welded portion 21w can be formed while avoiding the region on the tip side (region within a distance of less than 30%) where a temperature gradient occurs.
Thereby, the welded portion 21w can be formed avoiding areas where large thermal stress occurs. Therefore, the possibility that the welded portion 21w is damaged by thermal stress can be reduced.

[Modification 1]
As shown in FIGS. 8 and 9, like the outer jacket 21, the inner jacket 22 may have a double-tube structure with a closed end.
At this time, the cooling medium W can be ejected from the outward path 23 toward the closed part 21c of the outer jacket 21 by providing the jet port 22a in the closed part 22d that connects the outer pipe 22b and the inner pipe 22c.
As shown in FIG. 9, a plurality of jet ports 22a are provided at equal angular intervals around the central axis. In the case of FIG. 9, twelve jet ports 22a are provided.

[Modification 2]
As shown in FIGS. 10 and 11, the inner jacket 22 may have a hollow fin-like structure.

As shown in FIG. 11, the inner jackets 22 are formed at equal angular intervals around the central axis. In the case of FIG. 11, twelve fin-shaped inner jackets 22 are provided.

As shown in FIGS. 10 and 11, the fin-shaped inner jacket 22 protrudes from the outer tube 21a of the outer jacket 21 so as to taper toward the inner tube 21b, and has an outgoing path 23 defined inside (inside). has been done.
A spout 22a is formed at the tip of the fin-shaped inner jacket 22.

The cooling structure, screw feeder, and cooling method according to the present embodiment described above can be understood, for example, as follows.
That is, the cooling structure according to the first aspect of the present disclosure is a cooling structure (20) for a screw feeder (1) that supplies biomass fuel into the furnace of a gasifier (50), and defines a space inside. A closed tip (21c) is provided in the outer jacket (21) located inside the furnace and in the space of the outer jacket (21), and defines an outgoing path (23) for the cooling medium (W) inside. At the same time, a return path (24) for the cooling medium (W) is defined between the outer jacket (21) and the jet port (22a) from which the cooling medium (W) flowing through the outgoing path (23) is jetted out is connected to the outer jacket (21). An inner jacket (22) is formed at a position facing the closed end portion (21c) of the outer jacket (21).

According to the cooling structure (20) according to the present embodiment, the end portion (21c) which defines a space inside and is closed is provided in the space between the outer jacket (21) located inside the furnace and the outer jacket (21). The cooling medium defines an outgoing path (23) for the cooling medium (W) inside and defines an incoming path (24) for the cooling medium (W) between the outer jacket (21) and flows through the outgoing path (23). Since the spout (22a) through which (W) is spouted includes an inner jacket (22) formed at a position facing the closed tip (21c) of the outer jacket (21), the outer jacket The cooling medium (W) can be ejected from the ejection port (22a) of the inner jacket (22) toward the closed tip (21c) of the inner jacket (21). Thereby, the tip (21c) of the outer jacket (21), which is susceptible to the temperature in the furnace, can be intensively cooled with the cooling medium (W). In particular, by colliding the jet of the cooling medium (W) with the tip (21c) of the outer jacket (21), the tip (21c) of the outer jacket (21) can be cooled more efficiently. By cooling the tip (21c) of the outer jacket (21) in this way, it is possible to reduce the temperature difference (temperature gradient) that occurs at the tip side, and as a result, reduce thermal stress. .
Further, the outer jacket (21) can be maintained at an appropriate temperature by the cooling medium (W) guided from the outgoing path (23) to the incoming path (24) via the jet port (22a). Thereby, for example, it is possible to suppress condensation of water vapor contained in the gasification gas (G) or to suppress softening of lignin contained in biomass fuel.

In the first aspect, the cooling structure according to a second aspect of the present disclosure includes a flow rate adjustment section (34) that adjusts the flow rate of the cooling medium (W) supplied to the outgoing path (23), and a control section (36). , the control unit (36) controls the flow rate adjustment unit (34) so that the flow velocity of the cooling medium (W) in the outgoing path (23) is 1 m/s or more and 4 m/s or less, and performs cooling. Adjust the flow rate of the medium (W).

According to the cooling structure (20) according to this aspect, the flow rate adjustment section (34) that adjusts the flow rate of the cooling medium (W) supplied to the outgoing path (23) and the control section (36) are provided, and the control section (36) is provided. The part (36) controls the flow rate adjusting part to adjust the flow rate of the cooling medium (W) so that the flow velocity of the cooling medium (W) in the outward path (23) is 1 m/s or more and 4 m/s or less. A sufficient amount of the cooling medium (W) can be uniformly ejected from each ejection port (22a) while reducing the pressure loss in the outward path (23) as much as possible.

In the first aspect or the second aspect, the cooling structure according to a third aspect of the present disclosure includes a temperature adjustment section (35) that adjusts the temperature of the cooling medium (W) supplied to the outgoing path (23), and It includes a temperature sensor (33) that measures the temperature of the jacket (21) and a control section (36), and the control section (36) adjusts the temperature based on the information acquired from the temperature sensor (33). (35) to adjust the temperature of the cooling medium (W).

According to the cooling structure (20) according to the present aspect, the temperature control section (35) adjusts the temperature of the cooling medium (W) supplied to the outward path (23), and the temperature control section (35) measures the temperature of the outer jacket (21). It includes a sensor (33) and a control section (36), and the control section (36) controls the temperature adjustment section (35) based on the information acquired from the temperature sensor (33) to control the cooling medium (W). Therefore, the temperature of the outer jacket (21) can be maintained at a desired temperature by adjusting the temperature of the cooling medium (W).

In the cooling structure according to a fourth aspect of the present disclosure, in the third aspect, the control unit (36) controls the temperature so that the temperature of the outer jacket (21) is maintained at a temperature of 80°C or more and 100°C or less. The temperature of the cooling medium (W) is adjusted by controlling the adjustment section (35).

According to the cooling structure (20) according to this aspect, the control unit (36) controls the temperature adjustment unit (35) so that the temperature of the outer jacket (21) is maintained at a temperature of 80°C or more and 100°C or less. This controls the temperature of the cooling medium (W), thereby suppressing the condensation of water vapor contained in the gasified gas (G) flowing from the furnace, and also suppressing the condensation of water vapor contained in biomass fuel (e.g. wood-based). The softening of lignin can be suppressed. By suppressing the condensation of water vapor, the possibility that the biomass fuel becomes wet and the screw feeder (1) becomes clogged can be reduced. Moreover, by suppressing the softening of lignin, it is possible to reduce the possibility that biomass fuel will adhere to lignin and clog the screw feeder (1).

In the cooling structure according to a fifth aspect of the present disclosure, in any one of the first to fourth aspects, the outer jacket (21) includes an outer tube (21a) extending along the axis (X) direction and an inner tube (21a) extending along the axis (X) direction. The space has a double pipe structure including a pipe (21b), and the space provided with the inner jacket (22) is defined between the outer pipe (21a) and the inner pipe (21b).

According to the cooling structure (20) according to this aspect, the outer jacket (21) has a double tube structure having an outer tube (21a) and an inner tube (21b) extending along the axis (X) direction. Since the space in which the outer jacket (21) is provided is defined between the outer tube (21a) and the inner tube (21b), the inner jacket (22) can be provided inside the double tube structure. .

In the cooling structure according to a sixth aspect of the present disclosure, in the fifth aspect, the outer jacket (21) has a tip side portion including the tip portion (21c) divided along the direction of the axis (X). (21t) and a main body portion (21m) other than the tip side portion (21t).

According to the cooling structure (20) according to this embodiment, the outer jacket (21) is divided along the direction of the axis (X), and includes a tip side portion (21t) including the tip portion (21c) and a tip side portion. (21t), the position of the inner jacket (22) and the main body (21m) can be adjusted while visually checking, making it easy to create a highly accurate cooling structure 20. can be manufactured.

In the cooling structure according to a seventh aspect of the present disclosure, in the sixth aspect, the tip side portion (21t) and the main body portion (21m) are joined at a welded portion (21w), and the welded portion (21w) includes: It is formed at a distance of 30% or more of the inner diameter of the inner tube (21b) from the tip (21c).

According to the cooling structure (20) according to the present aspect, the tip side portion (21t) and the main body portion (21m) are joined at the welded portion (21w), and the welded portion (21w) is inwardly connected from the tip portion (21c). Since they are formed at a distance of 30% or more of the inner diameter of the tube (21b), the area on the tip (21c) side where a large temperature difference (temperature gradient) occurs (area within a distance of less than 30%) is The welded portion (21w) can be formed by avoiding this. Thereby, the welded portion (21w) can be formed avoiding areas where large thermal stress occurs. Therefore, the possibility that the welded portion (21w) is damaged by thermal stress can be reduced.

A screw feeder (1) according to an eighth aspect of the present disclosure includes the cooling structure (20) according to any one of the first to seventh aspects, and a screw (11), and the cooling structure (20) The outer jacket (21) is a casing that accommodates the screw (11).

A cooling method according to a ninth aspect of the present disclosure is a cooling method using the cooling structure (20) according to any one of the first to seventh aspects, in which a cooling medium (W ) to make the cooling medium (W) collide with the closed tip (21c) of the outer jacket (21).

1 Screw feeder 11 Screw 11a Rotating shaft 11b Vane 12 Bearing 20 Cooling structure (casing)
21 Outer jacket 21a Outer tube 21b Inner tube 21c Closure part (tip part)
21m Main body part 21t Tip side part 21w Welded part 22 Inner jacket 22a Spout 22b Outer pipe 22c Inner pipe 22d Closure part 23 Outgoing path 24 Incoming path 31 Motor 32 Fuel supply pipe 33 Temperature sensor 34 Circulation pump (flow rate adjustment part)
35 Temperature adjustment section 35a Heat exchanger 35b Heating cooler 36 Control section 50 Gasification furnace 51 Refractory material 52 Gasification furnace outer wall 53 Mounting seat 54 Heat insulating material G Synthetic gas L1 Supply line L2 Discharge line W Coolant X Rotation axis

Claims (9)

A cooling structure for a screw feeder that supplies biomass fuel into a gasifier furnace, the cooling structure comprising:
an outer jacket defining a space therein and having a closed end located inside the furnace;
The spout port is provided in the space of the outer jacket, defines an outgoing path for the cooling medium therein, defines an incoming path for the cooling medium between the outer jacket, and ejects the cooling medium flowing through the outgoing path. an inner jacket formed at a position facing the closed tip of the outer jacket;
Cooling structure equipped with. a flow rate adjustment unit that adjusts the flow rate of the cooling medium supplied to the outward path;
a control unit;
Equipped with
The cooling structure according to claim 1, wherein the control section controls the flow rate adjustment section to adjust the flow rate of the cooling medium so that the flow velocity of the cooling medium on the outward path is 1 m/s or more and 4 m/s or less. a temperature adjustment section that adjusts the temperature of the cooling medium supplied to the outward path;
a temperature sensor that measures the temperature of the outer jacket;
a control unit;
Equipped with
The cooling structure according to claim 1, wherein the control section controls the temperature adjustment section based on information acquired from the temperature sensor to adjust the temperature of the cooling medium. The cooling structure according to claim 3, wherein the control unit controls the temperature adjustment unit to adjust the temperature of the cooling medium so that the temperature of the outer jacket is maintained at a temperature of 80°C or more and 100°C or less. The outer jacket has a double tube structure having an outer tube and an inner tube extending along the axial direction,
The cooling structure according to claim 1, wherein the space in which the inner jacket is provided is defined between the outer tube and the inner tube. 6. The cooling structure according to claim 5, wherein the outer jacket is divided along the direction of the axis and has a tip side portion including the tip portion and a main body portion other than the tip side portion. The tip side portion and the main body portion are joined at a welded portion,
The cooling structure according to claim 6, wherein the welded portion is formed at a distance of 30% or more of the inner diameter of the inner tube from the tip end. The cooling structure according to claim 1;
screw and
Equipped with
The outer jacket of the cooling structure is a casing that accommodates the screw. A cooling method using the cooling structure according to claim 1,
A cooling method in which a cooling medium is jetted out from the jetting port and collided with the closed end portion of the outer jacket.