JP5393293B2 - Dust feeder - Google Patents

Description

  The present invention relates to a dust supply device for supplying waste such as municipal waste to a gasification furnace, an incinerator or the like.

2. Description of the Related Art Conventionally, as a dust supply device for supplying waste such as municipal waste to an incinerator, a gasification furnace, etc., there is one provided with a biaxial screw (see, for example, Patent Document 1).
This twin-screw type dust feeder has two screws arranged in parallel in a casing. The two screws are rotated and charged from a charging hopper provided in the upper part of the casing. The amount of waste generated is supplied to the incinerator. In this dust supply device, the twist direction and the rotation direction of the blades of the two screws are opposite to each other, and the rotation speed is the same.

Japanese Patent Publication No.58-57650

  According to the configuration of the above conventional dust feeder, the waste conveyed by the two screws is moved by the rotation of its blades, but because the rotation speed is the same, the waste is integrated and consolidated. This grows up and is transported into the combustion furnace, so that there is a problem that a so-called “sloppy” phenomenon occurs.

  In view of the above, an object of the present invention is to provide a dust supply device that prevents waste from being accumulated and consolidated, and can quantitatively supply waste.

In order to solve the above-described problem, a dust supply apparatus according to claim 1 of the present invention is a dust supply apparatus for supplying waste to a gasification furnace or the like, and is provided with a waste input section on one end side. In addition, a pair of left and right waste transporting screws rotatably disposed in a casing provided with a waste discharging section on the other end side, two electric motors for rotating these screws, and the both screws A supply amount detecting means capable of detecting the supply amount of waste in the casing in which is disposed, and a control device for controlling each of the electric motors,
The control device
A reference speed setting unit for setting a reference rotation speed of each of the screws;
Left and right speed change imparting units that impart a change in rotational speed to the left and right screws to the reference rotational speed set by the reference speed setting unit,
A speed correction unit having a speed correction curve that inputs the supply amount detected by the supply amount detection means and increases or decreases the rotational speed of each screw based on the supply amount;
In the speed change applying unit, a speed change curve having a predetermined period and a predetermined amplitude is created, and a speed change command in which phases of both speed change curves for the left and right screws are 180 degrees different from each other is output.
Further, the maximum value of the phase difference between the left and right screws is made larger than the pitch of the screw blades, and the screw rotational speed is changed from the waste input portion opening end to the waste discharge portion. Make it shorter than the time to pass the distance to the tip,
The speed correction curve in the speed correction unit decreases the rotation speed when the supply amount is large, and increases the rotation speed when the supply amount is small.

Further, the sheet dust device according to claim 2, the variation period T of the rotational speed of the screw provided with a change in velocity imparted portion in the sheet dust device according to claim 1, and so as to satisfy the following formula (1) Is.

Ｎ′右：動き始めからＴ／２後までの右スクリューの回転数の平均値（ｍｉｎ^−１）
Ｎ′左：動き始めからＴ／２後までの左スクリューの回転数の平均値（ｍｉｎ^−１）
Ｐ：スクリュー羽根のピッチ（ｍｍ）
Ｔ：回転速度の変動周期（ｓｅｃ）
さらに、請求項３に係る給じん装置は、請求項２に記載の給じん装置における速度変化付与部で与えられるスクリューの回転速度の変動周期Ｔが、請求項２に記載の（１）式に加えて下記（２）式の範囲内となるようにしたものである。

N′Right: Average value of the number of rotations of the right screw from the start of movement to after T / 2 (min ⁻¹ )
N′Left: Average value of the number of rotations of the left screw from the start of movement to after T / 2 (min ⁻¹ )
P: Screw blade pitch (mm)
T: Rotational speed fluctuation cycle (sec)
Furthermore, paper dust device according to claim 3, the variation period T of the rotational speed of the screw provided with a change in velocity imparted portion in the sheet dust device according to claim 2, in (1) of claim 2 In addition, it falls within the range of the following formula (2).

T <L × 60 / (P × N) (2)
L: Distance from the opening end of the feeding part to the screw tip (mm)
N: Reference rotation speed (reference rotation speed per minute) (min ⁻¹ )
P: Screw blade pitch (mm)
T: Rotational speed fluctuation cycle (sec)

  According to the above configuration, the speed change applying unit rotates the left and right screws in opposite directions, and the rotational speeds of both screws are increased and decreased in opposite directions with a predetermined period. Is periodically changed, and the waste compaction state can be unraveled by the shearing force between the right screw blade and the right screw blade.

It is a schematic sectional drawing of the gasification furnace in which the dust feeder of the Example of this invention is used. It is a principal part notch top view of the same dust supply apparatus. It is sectional drawing of the same dust supply apparatus. It is AA sectional drawing of FIG. It is a block diagram which shows schematic structure of the control apparatus of the same dust supply apparatus. It is a graph which shows the correction curve in the correction function preparation part of the control apparatus. It is a graph which shows the speed change curve in the speed change function preparation part of the control apparatus. It is a principal part top view explaining generation of shearing force at the time of rotation speed control by the control device. The modification of the speed change curve by the same control apparatus is shown, (a) is a graph of a speed change curve, (b) is a graph of the phase difference.

Hereinafter, the dust supply apparatus according to the embodiment of the present invention will be described based on specific examples.
In the present embodiment, for example, a dust supply apparatus that supplies waste such as municipal waste (hereinafter simply referred to as garbage) to a gasifier will be described.

  As shown in FIG. 1, in the gasification chamber 3 formed in the furnace body 2 of the gasification furnace 1, a fluidized bed G made of a layer material such as sand is formed in the lower part, and for supplying air. The fan 4 is configured to supply the combustion air for waste and the fluidizing air for the layer material into the furnace body 2 via the combustion air line L1 and the flow air line L2. The side wall portion of the furnace main body 2 is provided with a garbage inlet 2a for introducing the waste to be gasified into the gasification chamber by the dust feeder 11 according to the present invention.

Next, the dust feeder 11 according to the present invention will be described.
As the dust feeder 11, a twin screw type feeder provided with two dust conveying screws is used.

  That is, as shown in FIG. 2 to FIG. 4, the dust supply device 11 has two cylinders arranged in parallel so that parts of the cylinders are overlapped with each other, and a dust transport space chamber 13 is formed on the left and right. A cylindrical casing 12 having a cross-sectional cross-section, a left and right dust transfer screw 14 rotatably disposed in a dust transfer space chamber 13 formed in the cylindrical casing 12, and each of these The motor 14 is configured to rotate the screw 14 via a pair of sprockets 16 and a chain 17. Each screw 14 includes a shaft portion 14a connected to the electric motor 15, and a blade portion (also referred to as a screw blade) 14b wound around the outer peripheral surface of the shaft portion 14a. In addition, a hopper-shaped charging part 12a for charging garbage is provided at the upper part on one end side of the cylindrical casing 12, and a discharging part 12b for discharging dust is provided at the lower side on the other end side. ing. In addition, although the cross section of the said cylindrical casing 12 is made into bowl shape, it is not limited to this shape.

  In the upper portion of the cylindrical casing 12 near the other end, the amount of dust conveyed by each screw 14, that is, gas, in a total of three locations between the screws 14 and 14 and outside the screws 14, 14. Waste supply amount detection means 18 (18A, 18B, 18C) for detecting the amount of waste supply to the conversion furnace 1 (also referred to as a waste transport amount) is provided.

  Each of these dust supply amount detecting means 18 is rotatable in a direction orthogonal to the dust supply direction (conveying direction) in a rectangular frame-shaped mounting portion 12c projecting from the upper portion of the cylindrical casing 12. The provided support shaft body 21 and a dust detection flapper (waste detection) which is attached to the support shaft body 21 and whose lower end portion is supported on the screw 14 so as to be swingable in a vertical plane. Plate) 22 and an inclination of the support shaft 21 that is provided at one end of the support shaft 21 and is upwardly inclined with respect to the rotation angle of the support shaft 21, that is, the reference posture of the flapper 22 (for example, a vertical posture or a posture that is a predetermined angle upward from the vertical posture). And an angle detector (for example, an angle detection encoder is used) 23 for detecting an angle (hereinafter also referred to as a detection angle) θ.

As shown in FIG. 5, the dust feeder 11 is provided with a control device 31 that controls the number of rotations, that is, the rotation speed of each screw 14.
Briefly speaking, the function of the control device 31 is such that the left and right screws 14 (right side 14A, left side 14B) are rotated in opposite directions, and the rotational speeds of both screws 14 are opposite to each other with a predetermined cycle, that is As the value increases, the other decreases.

  The control device 31 sets a reference rotation speed (reference rotation speed) of the screw 14 and controls a rotation speed of each motor 15 (a so-called inverter control unit) 15a to a reference rotation speed signal (reference signal). A reference speed setting unit 32 that outputs a rotation speed command), and a speed change signal (also referred to as a speed change command) is applied to the reference rotation speed signal from the reference speed setting unit 32 to rotate the rotation speed of the motor 15, that is, the screw 14A. , 14B for controlling the rotational speed of each of the first and second speed change applying sections 33 (33A, 33B), and in addition to the speed change signals obtained by the respective speed change applying sections 33, the screw 14 A speed correction signal (also referred to as a speed correction command) for correcting each rotation speed based on the thickness of the dust layer conveyed by the first is output. Preliminary second speed correcting section 34 (34A, 34B) is constructed from a.

  Each of the speed change applying units 33 includes a cycle setting unit 41 that sets a fluctuation cycle for changing the rotation speed, an amplitude setting unit 42 that sets the amplitude of the change (the range of increase and decrease), and these A speed change function creating section 43 that creates a speed change function (specifically, a speed change curve) by inputting the period and amplitude set by both setting sections 41 and 42, and this speed change function creating section The speed change function value created at 43 is added to a reference rotational speed signal, and a change signal adding unit 44 is applied (biased).

  The first speed correction unit 34A inputs the detection angle from the angle detector 23A and the detection angle from the central angle detector 23C arranged on the right side, and detects both of these detection angles (for example, the average value of both detection angles). ) To obtain a correction value for correcting (adjusting) the rotational speed of the right screw 14A in accordance with the amount of dust supply obtained by the speed correction function creation unit having a speed correction function (specifically, a speed correction curve). 46 and a correction signal multiplication unit 47 that multiplies the rotation speed signal by the speed correction function value obtained by the speed correction function creation unit 46.

  Similarly to the first speed correction unit 34A, the second speed correction unit 34B receives the detection angle from the angle detector 23B arranged on the left side and the detection angle from the central angle detector 23C. A speed correction function (specifically, a correction value for obtaining a correction value for correcting (adjusting) the rotational speed of the left screw 14B in accordance with the amount of dust supply obtained from both detection angles (for example, an average value of both detection angles). A speed correction function generator 46 having a speed correction curve) and a correction signal multiplier 47 for multiplying the rotational speed signal by the speed correction function value obtained by the speed correction function generator 46.

  As shown in FIG. 6, the speed correction function provided in the speed correction function creation unit 46 is a function such that the correction value α decreases as the detection angle θ increases. This indicates that as the detection angle θ increases, the amount of dust that moves in the dust transport space 13 increases, and in this case, the amount of dust supplied decreases.

Next, a control method will be described.
First, the reference rotation speed setting unit 32 sets the reference rotation speed of the screw 14 and the change period (T: predetermined cycle) in which changes are applied by the cycle setting unit 41 and the amplitude setting unit 42 of each speed change applying unit 33. ) And an amplitude W which is a change width of the rotation speed.

  When the operation is started, a reference rotation speed signal is output from the reference speed setting unit 32, and a speed change function in which the change period and the amplitude are added (synthesized) is created by the speed change applying unit 33. A speed change signal obtained from the speed change function is output to the change signal adding unit 44, where the speed change signal is added to the reference rotation speed signal to become a new rotation speed signal.

  Then, when the operation is continued and the garbage moves in the cylindrical casing 12 and the amount of waste supply increases, the waste supply amount detection means 18 detects this. That is, when the dust layer surface (layer height) increases, the rotational speed of the screw 14 is corrected according to the height.

For example, the detection angle θ from the dust supply amount detection means 18A and 18C corresponding to both sides of the dust transport space 13 (13A) where the right screw 14A is disposed is input to the first speed correction unit 34 (34A). Then, for example, the average value is used as a representative value, a correction value corresponding to the representative value is obtained from the speed correction function, and a speed correction signal that is the correction value is multiplied by the rotation speed signal. For example, when the detected angle is θ _{1 and the} amount of dust supply is large, the correction value (for example, 0.7) α ₁ corresponding to the detected angle is multiplied to reduce the value of the rotational speed signal (see FIG. 6). . That is, when the waste supply amount decreases, the correction value α becomes a large value and the rotation speed is increased.

Here, the speed change signal and the speed correction signal will be described.
As the speed change signal, for example, a sine waveform is used as shown in FIG.
For example, for the right screw 14A, as shown in (a), the rotational speed is increased along the sine curve, and when it exceeds 1/4 period, it is decreased to 3/4 period and then exceeds 3/4. And will be increased again. On the other hand, for the left screw 14B, as shown in (b), a curve opposite to the sine curve, that is, a cosine curve is used. Of course, the fluctuation period T and the amplitude W are the same as those on the right side.

Therefore, the screw 14B on the left side is decreased along the reverse sine curve, and is increased to 3/4 period when exceeding 1/4 period, and then decreased again when exceeding 3/4 period.
That is, as shown in FIG. 8, the left and right screws 14A and 14B generate a rotational speed difference corresponding to the amplitude of the sine curve in the 1/4 cycle and 3/4 cycle, respectively. Therefore, a reverse force (F) due to the difference in speed (F _A -F _B ) is generated between the blade portions 14b, 14b of the screws 14A, 14B, and a shearing force acts on the dust. Become.

  In other words, by performing such rotational speed control (rotational speed control), the phases of the blade portions 14b of the right and left screws 14 periodically change, and the blade portions 14b of the right screw 14A and the left screw 14B are changed. By the shearing force with the blade portion 14b, the compacted state of the dust can be unraveled (disintegrated).

  By the way, in order to surely unravel the compacted state of the dust, the maximum value of the phase difference S of the left and right screws 14 needs to be larger than the pitch P of the screw blades 14b. This is expressed by the following equation (1). Represented.

S _max > P (1)
By the way, since the phase difference S becomes maximum when T / 2 has elapsed, S _max is expressed by the following equation (2).

（２）式および（３）式中、
Ｎ′右：動き始めからＴ／２後までの右側スクリューの回転速度（毎分回転数）の平均値（ｍｉｎ^−１）
Ｎ′左：動き始めからＴ／２後までの左側スクリューの回転速度（毎分回転数）の平均値（ｍｉｎ^−１）
Ｐ：スクリュー羽根のピッチ（ｍｍ）
Ｔ：回転速度の変動周期（ｓｅｃ）を、それぞれ示す。

In the formulas (2) and (3),
N ′ right: average value (min ⁻¹ ) of the rotational speed (number of revolutions per minute) of the right screw from the start of movement to after T / 2
N′Left: Average value (min ⁻¹ ) of the rotation speed (number of rotations per minute) of the left screw from the start of movement to after T / 2
P: Screw blade pitch (mm)
T: The rotation speed fluctuation period (sec) is shown respectively.

  Further, as shown in FIG. 3, the distance from the leading end of the input portion 12 a serving as the base point of the compacted garbage B to the discharge port 12 b of the cylindrical casing 12, precisely to the tip of the screw 14 (distance: L). Therefore, since it is necessary to unravel the compacted state of the waste B, the fluctuation period T of the rotational speed needs to be shorter than the time during which the dust passes the distance L.

Therefore, the following equation (4) is obtained.
T <L × 60 / (P × N) (4)
L: Distance from the opening end of the feeding part to the screw tip (mm)
N: Reference rotation speed (number of rotations per minute) (min ⁻¹ )
P: Screw blade pitch (mm)
Therefore, the fluctuation cycle and amplitude for changing the rotation speed and the shape to be changed, for example, a sine wave are adopted so as to satisfy the above expressions (3) and (4).

  As described above, when the rotation speed of the left and right screws is the same ratio from the reference rotation speed and the rotation speed of the right screw increases, the rotation speed of the left screw decreases and the rotation speed of the right screw rotates. When is decreased, it is moved periodically so that the rotational speed of the left screw increases. That is, the left and right screws are rotated in opposite directions, and the rotational speeds of both screws are increased or decreased in opposite directions with a predetermined period.

  By controlling the rotational speed in this way, the phases of the left and right screw blades change periodically, and the compaction state of the dust can be unraveled by the shearing force between the right screw blade and the left screw blade. . Therefore, for example, there is no need to separately provide a device for unraveling the compacted state of the waste, which is economical.

By the way, in the said Example, although the sine waveform was used as a speed change function, you may use a rectangular wave as shown, for example in FIG.
FIG. 9A shows a rectangular waveform, and FIG. 9B shows a phase difference S due to both screws.

  Moreover, in the said Example, although the case where it applied to a gasification furnace was demonstrated, of course, it can apply also to another furnace, for example, an incinerator.

DESCRIPTION OF SYMBOLS 1 Gasification furnace 2 Furnace main body 3 Gasification chamber 11 Dust supply device 12 Cylindrical casing 13 Waste conveyance space chamber 14 Screw 14a Blade part 14b Shaft part 15 Electric motor 18 Waste supply amount detection means 31 Controller 32 Reference speed setting part 33 Speed change imparting section 34 Speed correction section 41 Period setting section 42 Amplitude setting section 43 Speed change function creating section 44 Change signal adding section 46 Correction function creating section 47 Correction signal multiplying section

Claims (3)

A dust supply device for supplying waste to a gasification furnace, etc., which is rotatable in a casing provided with a waste input part on one end side and a waste discharge part on the other end side A pair of left and right waste conveying screws, two electric motors for rotating both screws, and a supply amount detecting means capable of detecting the amount of waste supplied in the casing in which both screws are disposed And a control device for controlling each of the motors,
The control device
A reference speed setting unit for setting a reference rotation speed of each of the screws;
Left and right speed change imparting units that impart a change in rotational speed to the left and right screws to the reference rotational speed set by the reference speed setting unit,
A speed correction unit having a speed correction curve that inputs the supply amount detected by the supply amount detection means and increases or decreases the rotational speed of each screw based on the supply amount;
In the speed change applying unit, a speed change curve having a predetermined period and a predetermined amplitude is created, and a speed change command in which the phases of both speed change curves for the left and right screws are different by 180 degrees is output
Further, the maximum value of the phase difference between the left and right screws is made larger than the pitch of the screw blades, and the screw rotational speed is changed from the waste input portion opening end to the waste discharge portion. Make it shorter than the time to pass the distance to the tip,
The speed correction curve in the speed correction unit decreases the rotation speed when the supply amount is large, and increases the rotation speed when the supply amount is small. Variation period T of the rotational speed of the screw provided with a change in velocity imparted portion, the sheet dust device according to claim 1, characterized in that so as to satisfy the following formula (1).

N′Right: Average value of the number of rotations of the right screw from the start of movement to after T / 2 (min ⁻¹ )
N′Left: Average value of the number of rotations of the left screw from the start of movement to after T / 2 (min ⁻¹ )
P: Screw blade pitch (mm)
T: Rotational speed fluctuation cycle (sec) Claims fluctuation period T of the rotational speed of the screw provided with a change in velocity imparted portion, characterized in that in addition to (1) according to claim 2 was set to be within the scope of the following equation (2) 2. A dust feeding device according to 2.
T <L × 60 / (P × N) (2)
L: Distance from the opening end of the feeding part to the screw tip (mm)
N: Reference rotation speed (min ⁻¹ )
P: Screw blade pitch (mm)
T: Rotational speed fluctuation cycle (sec)

Images