JP4931695B2 - Pulverized coal supply device, pulverized coal supply control method, and pulverized coal supply control program - Google Patents

Description

  The present invention supplies a coal-fired power plant (coal) that supplies pulverized coal obtained by pulverizing coal to a boiler device as fuel, heats water by combustion to generate steam, and drives the turbine with the steam to generate power. The present invention relates to a pulverized coal supply device, a pulverized coal supply control method, and a pulverized coal supply control program used in a thermal power generation system).

  In general, in a coal-fired power plant that uses pulverized coal as fuel, coal stored in a coal yard is transported to a pulverized coal feeder by a coal transport mechanism such as a conveyor, and the coal is pulverized in the pulverized coal feeder. Use pulverized coal. Thereafter, the pulverized coal is sent as fuel from the pulverized coal supply device to the boiler device, and the pulverized coal is burned in the boiler device, and water is heated by this combustion to generate steam. In addition, oil may be supplied to the boiler device during combustion.

  The steam generated in the boiler device is supplied to the steam turbine, the generator is driven by the steam turbine, and power is generated by the generator. On the other hand, the steam that has passed through the steam turbine is condensed by a condenser and supplied to the boiler device together with makeup water.

  By the way, the pulverized coal supply apparatus includes a coal storage tank (coal bunker), a coal feeder, and a coal pulverizer (mill), and the coal bunker, the coal feeder, and the mill are in the vertical direction (vertical direction). From the upper side, the coal bunker, coal feeder, and mill are arranged in this order. Coal bunker temporarily stores the coal transported from the coal yard by the coal transport mechanism. Then, coal is supplied from the coal bunker to the coal feeder through the coal supply pipe.

  For example, a transport conveyor is built in the coal feeder, and the transport conveyor is rotationally driven in a horizontal direction by a drive unit such as a motor. The coal supplied from the coal supply pipe is transferred in the horizontal direction by the transport conveyor, and the coal is input from the transport conveyor to the coal supply inlet portion of the mill formed to be connected to the coal outlet at the end of the transport conveyor.

  Since the coal supplied from the coal bunker to the coal feeder is in a lump shape, the supply amount is not stable. For this reason, as described above, the coal supplied from the coal bunker to the mill is separated by horizontally separating the inlet and outlet of the coal feeder through the conveyor and adjusting and controlling the rotation speed of the conveyor. The amount of coal supplied to the mill is stabilized in such a way that the amount of feed is constant per unit time.

  The coal supplied to the mill is finely pulverized to become pulverized coal, and is fed into the boiler device by pneumatic feeding, and the pulverized coal is burned together with air (air is fed from the ventilator to the boiler device). As described above, water is heated in the boiler device to generate steam, and the steam turbine is driven by the steam.

In the above-described pulverized coal supply apparatus, a coal gate valve for opening and closing the coal supply pipe is disposed in the coal supply pipe immediately above the coal feeder, and the call gate valve is manually opened or closed. Driven. In general, even if the coal gate is opened by driving the coal gate valve in the opening direction, if the coal feeder is stopped, no coal is supplied to the mill, If it is stopped for a week or more, for safety, the coal gate is closed by manually driving the call gate valve in the closing direction. Is also stopped).
JP 2002-310423 A

  By the way, as described above, when the mill and the coal feeder are stopped and the coal gate valve is manually driven in the closing direction to close the coal feeding pipe, the coal feeding pipes after the coal gate valve (from the coal gate valve) Coal remains accumulated between the lower coal feed pipe) and the conveyor belt. Then, when restarting the operation of the mill, the coal gate valve is manually driven in the opening direction to open the coal feeding pipe and the coal feeder is driven (that is, the transport conveyor is driven to rotate). However, after the mill has been stopped for a long period of time, the coal remaining in the state between the coal feeding pipe and the conveyor belt after the coal gate valve is dried air flowing from the mill side, etc. It solidifies and becomes a large lump, which may cause so-called coal clogging in the coal supply pipe.

  And when coal clogging occurs in the coal supply pipe, when the driving of the mill is resumed, coal is not smoothly supplied from the coal bunker to the coal feeder, and coal is not supplied satisfactorily from the coal feeder to the mill. (Coal is not supplied to the mill or the amount of coal supplied to the mill varies greatly). As a result, there is a problem that pulverized coal is not stably supplied from the mill to the boiler device, which hinders combustion in the boiler device.

  An object of the present invention is to provide a pulverized coal supply apparatus, a pulverized coal supply control method, and a pulverized coal control program capable of stably supplying coal to the mill even when the operation is resumed after the mill has been stopped for a long time. It is to provide.

  A pulverized coal supply apparatus according to the present invention includes a pulverized coal machine that finely pulverizes coal into pulverized coal and supplies the coal as a fuel to a boiler apparatus, a coal bunker for storing the coal and supplying the coal to the pulverized coal machine, A coal feeder disposed between the pulverized coal machine and the coal bunker for adjusting the amount of coal supplied from the coal bunker to the pulverized coal machine, and from the coal bunker to the coal supply A valve mechanism for opening and closing the coal supply passage is provided in the coal supply passage leading to the machine, and further, when a predetermined first time elapses after the coal supply passage is closed by the valve mechanism. The first control means for stopping the coal feeder, and the second control means for stopping the pulverized coal machine when a second time has elapsed after stopping the coal feeder. It is.

  The pulverized coal supply apparatus of the present invention further includes third control means for gradually reducing the amount of coal supplied from the coal feeder to the pulverized coal machine when the operation switch is turned off, and the coal feeder. And a fourth control means for closing the coal supply passage by the valve mechanism when the amount of coal supplied to the pulverized coal machine is reduced to a predetermined amount.

  In the pulverized coal supply apparatus according to the present invention, the coal feeder receives the coal from an outlet of the coal feeding passage, and transports the coal to an inlet side of the pulverized coal machine, and a drive that drives the carrier. And the third control means gradually decelerates the carrier from a predetermined constant speed to a predetermined speed corresponding to the predetermined amount. The first time is determined according to, for example, the moving speed of the transport body and the volume of the coal supply passage from the valve mechanism to the outlet of the coal supply passage.

  When the pulverized coal supply device of the present invention restarts the operation after stopping the pulverized coal machine, after driving the pulverized coal machine, a fifth control means for driving the coal feeder after a third time has elapsed. And a sixth control means for opening the coal supply passage by the valve mechanism when a fourth time elapses after the coal feeder is driven.

  The pulverized coal supply apparatus according to the present invention is a fifth control unit that drives the carrier when a third time has elapsed after driving the pulverized coal machine when restarting the operation after stopping the pulverized coal machine. And a sixth control means for opening the coal supply passage by the valve mechanism when a fourth time has elapsed after driving the transport body, and at least the fourth time after driving the transport body The time until the speed of the transport body reaches a constant speed is set.

  The pulverized coal supply control method of the present invention includes a pulverized coal machine that pulverizes coal into pulverized coal and supplies it as a fuel to a boiler device, the coal is stored, and the coal is supplied to the pulverized coal machine. A coal bunker; and a coal feeder disposed between the pulverized coal machine and the coal bunker for adjusting the amount of coal supplied from the coal bunker to the pulverized coal machine. Used in a pulverized coal supply device provided with a valve mechanism for opening and closing the coal supply passage to the coal supply passage from the first to the coal feeder, and the valve mechanism is driven and controlled to close the coal supply passage. The second step of stopping the coal feeder when a predetermined first time has elapsed after closing the coal feeding passage, and the second time after stopping the coal feeder. And having a third step of stopping the pulverized coal machine after a lapse of time. It is an butterfly.

  The pulverized coal supply control program according to the present invention includes a pulverized coal machine that finely pulverizes coal into pulverized coal and supplies it as a fuel to a boiler device, the coal is stored, and the coal is supplied to the pulverized coal machine. A coal bunker; and a coal feeder disposed between the pulverized coal machine and the coal bunker for adjusting the amount of coal supplied from the coal bunker to the pulverized coal machine. Used in a pulverized coal supply device provided with a valve mechanism for opening and closing the coal supply passage in a coal supply passage extending from the coal feeder to the coal feeder, and the computer controls the valve mechanism to control the coal supply passage. A first step of closing, a second step of stopping the coal feeder when a predetermined first time has elapsed after closing the coal feeding passage, and a second step after stopping the coal feeder. The pulverized coal machine stops when the time of It is characterized in that to execute a third step that.

  As described above, according to the present invention, after closing the coal supply passage by the valve mechanism, the coal feeder is stopped when a predetermined first time elapses, and then the second time elapses. Then, since the pulverized coal machine is stopped, at least coal in the coal supply passage after the valve mechanism is supplied to the coal feeder, and coal does not stay in the coal supply passage after the valve mechanism. Therefore, even if the pulverized coal machine is stopped for a long time, there is an effect that no coal clogging occurs in the coal supply passage. As a result, when restarting the operation of the pulverized coal machine, there is an effect that the coal can be stably supplied to the pulverized coal machine.

  In the present invention, the amount of coal supplied from the coal feeder to the pulverized coal machine is gradually reduced, and when the amount of coal supplied from the coal feeder to the pulverized coal machine reaches a predetermined amount, the valve mechanism opens the coal supply passage. Since it was made to close, there exists an effect that coal clogging to a coal supply passage can be prevented reliably while supplying coal from a coal feeder to a pulverized coal machine.

  In the present invention, the speed of the transport body is gradually reduced from a predetermined constant speed to a predetermined speed, thereby adjusting the amount of coal supplied from the coal feeder to the pulverized coal machine. In addition, there is an effect that coal clogging can be avoided while adjusting the amount of coal supplied from the coal feeder to the pulverized coal machine.

  In the present invention, when restarting the operation after stopping the pulverized coal machine, when the third time has elapsed after driving the pulverized coal machine, the coal feeder is driven, and after the coal feeder is driven, the fourth time is reached. After the passage, the coal supply passage was opened by the valve mechanism. As a result, the coal remaining in the coal feeder was first sent to the pulverizer. As a result, even after the pulverizer was stopped for a long time, the pulverizer was stable. There is an effect that coal can be supplied.

  Hereinafter, an example of a pulverized coal supply apparatus according to an embodiment of the present invention will be described with reference to the drawings. Here, first, an outline of a coal-fired power plant using a pulverized coal supply device will be described with reference to FIG. The illustrated coal-fired power plant is provided with a boiler device 13 for heating water to generate steam (hereinafter simply referred to as steam), and the boiler device 13 passes through a steam turbine 15 with a condenser 17. The water obtained by condensing the steam and makeup water are supplied by the water supply pump 18.

  On the other hand, pulverized coal is supplied to the boiler device 13 from the pulverized coal supply device as fuel. The pulverized coal supply apparatus has a coal bunker 11, a coal feeder 23, and a pulverized coal machine (mill) 12. The coal bunker 11 is transported from a coal storage (not shown) to a conveyor (with a dustproof cover). The coal is transported by 14, and the coal is temporarily stored in the coal bunker 11.

  Coal stored in the coal bunker 11 is sent to the coal feeder 23, and the coal feeder 23 stably feeds a predetermined amount (quantitative amount) of coal (coal lump) to the mill 12 as described later ( That is, the coal feeder 23 adjusts the amount of coal supplied from the coal bunker 11 to the mill 12), and the mill 12 finely pulverizes the coal into pulverized coal. The pulverized coal is sent from the mill 12 to the boiler device 13 as fuel by pneumatic feeding.

  A boiler is defined in the boiler device 13. In the illustrated example, oil is sent to the furnace through an oil feeding pipe (not shown). In the furnace, oil is burned and pulverized coal is used. Combustion (note that combustion air is sent to the boiler device 13 by a ventilator (not shown)). That is, two-stage combustion is performed. By this combustion, the water supplied from the water supply pump 18 is heated to become steam, and this steam is sent from the boiler device 13 to the steam turbine 15.

  Although not shown in the drawings, in more detail, the boiler device 13 includes a furnace that burns pulverized coal, a heater (heat exchange unit) that heats the furnace, and an air supply device (a ventilator) that supplies air to the furnace. ) And are provided. The furnace is heated by a heater and burns the pulverized coal supplied from the mill 12 via the pulverized coal pipe together with the air supplied from the air supply unit.

  In the furnace, a first superheater (heat exchange unit) is arranged, and a second superheater (heat exchange unit) is subsequently arranged therefrom. Furthermore, from the vicinity of the terminal end of the second superheater, a primary economizer (heat exchange unit) and a secondary economizer (heat exchange unit) are provided in two stages. Here, the primary economizer and the secondary economizer are heat transfer surface groups provided for preheating boiler feedwater using heat held by the combustion gas.

  As described above, the steam supplied from the boiler device 13 causes the steam turbine 15 to rotationally drive the generator 16, thereby generating electric power, and via a transformer and a switching station (both not shown). Electric power is transmitted through a transmission line (not shown). The steam that has passed through the steam turbine 15 is condensed by the condenser 17 and supplied to the boiler device 13 by the feed water pump 18 together with makeup water.

  On the other hand, the exhaust gas after combustion in the boiler device 13 is passed through a flue gas denitration device, an air preheater for preheating air sent to the boiler device 13, a dust collector, and a flue gas desulfurization device (both not shown). Exhausted from high chimney. Further, combustion products (residues) generated in the boiler device 13 are discharged from the lower side of the boiler device 13.

  Here, the aforementioned pulverized coal supply apparatus will be described with reference to FIG. As described above, the pulverized coal supply apparatus includes the funnel-shaped coal bunker 11, the coal feeder 23, and the mill 12, and the coal bunker 11, the coal feeder 23, and the mill 12 are arranged in the vertical direction. To coal bunker 11, coal feeder 23, and mill 12 are disposed in this order (that is, coal feeder 23 is disposed between coal bunker 11 and mill 12). The coal bunker 11 and the coal feeder 23 are connected by a first coal supply pipe (coal supply passage) 21, and the coal feeder 23 and the mill 12 are connected by a second coal supply pipe 24. In addition, as shown in the drawing, the first coal supply pipe 21 and the second coal supply pipe 24 are shifted in the horizontal direction from each other in the attachment position to the coal feeder 23.

  Further, just above the coal feeder 23, the first coal supply pipe 21 is provided with a call gate valve (valve mechanism) 22 for opening and closing the first coal supply pipe 21. Although not shown in FIG. 1, the call gate valve 22 has a valve housing and a valve body (valve rod) disposed in the valve housing, and is driven by a drive unit such as a motor 25. The valve body is rotationally driven in the opening direction or the closing direction, and the first coal supply pipe 21 is opened and closed.

  As shown in the drawing, an endless transport belt (transport body) 26 is disposed in the coal feeder 23, and the transport belt 26 extends in the horizontal direction. The conveyor belt 26 is supported by a driven roller 27a and a driving roller 27b. When the driving roller 27b is rotationally driven by a driving unit such as a motor 28, the conveyor belt 26 rotates in a direction indicated by a solid line arrow in the figure.

  The center of the drive roller 27b is positioned on the right side of the outlet of the first coal supply pipe 21 (that is, the center of the drive roller 27b is positioned on the right side of the central axis of the second coal supply pipe 24). The left end of the driven roller 27a is located on the central axis of the second coal supply pipe 24 (that is, the center of the driven roller 27a is on the right side of the central axis of the second coal supply pipe 24). Will be located).

  As a result, the coal supplied from the first coal supply pipe 21 to the coal feeder 23 is supplied onto the conveyor belt 26, and after the coal is transferred in the horizontal direction by the rotation of the conveyor belt 26. Then, it is supplied (introduced) to the second coal supply pipe 24 from the left end side of the conveyor belt 26. At this time, an amount of coal corresponding to the rotational speed of the conveyor belt 26 is supplied to the second coal supply pipe 24, that is, the mill 12 per unit time.

  Here, the call gate valve 22 will be described with reference to FIGS. 3 and 4. FIG. 3 is a view in which a part of the valve housing (housing) is broken (the left side in the drawing is broken) and is viewed from above, and FIG. 4 is a cross-sectional view taken along line AA in FIG. In the illustrated example, the diameter of the first coal supply pipe 21 is in the range of 80 cm to 120 cm, and the housing 40 of the call gate valve 22 is approximately 187 cm wide and approximately 110 cm long in the horizontal cross section. The total weight of 22 is about 850 kg.

  First, referring to FIG. 3, a coal gate valve shaft body 44 is disposed at the center (on the center line) of the box-shaped housing 40, and both ends of the coal gate valve shaft body 44 are supported by the side walls of the housing 40. ing. As will be described later, a valve rod 52 is provided in the call gate valve shaft body 44, and a sprocket 45 is fitted into the valve rod 52. On the other hand, the motor 25 is attached to the side wall of the housing 40, and a sprocket 41 is fitted on the shaft of the motor 25. The sprocket 41 is connected to the sprocket 45 by a roller chain 42, and the valve rod 52 rotates as will be described later by the rotational drive of the motor 25. The motor 25 is provided with a limit switch 25a, and the limit switch 25a detects the amount of rotation of the motor 25 in a closed position and an open position, which will be described later.

  A handle 43 for manually rotating the valve stem 52 is attached to one end (the lower end in FIG. 3) of the valve stem 52 in order to cope with a case where the motor 25 fails. That is, when the valve stem 52 cannot be rotated by the motor 25, the valve stem 52 can be rotated in an arbitrary direction by rotating the handle 43 by hand.

  Referring to FIG. 4, the call gate valve shaft body 44 includes a valve shaft body housing 46, and a valve rod 52 is rotatably supported by the valve shaft body housing 46. As shown in the figure, the above-described sprocket 45 is fitted into the valve stem 52, and sprockets 47 and 48 are fitted at a predetermined interval (for example, the diameter of the first coal supply pipe 21). A packing body 53 is disposed on the valve stem 52 between the sprocket 45 and the sprocket 48.

  A bush 50 is disposed at the upper end of the valve stem 52 and is received by the thrust ring receiver 51 via the thrust ring 51a. The upper end of the valve stem 52 is attached to a bracket 49 via a bearing, and this bracket 49 is attached to the valve shaft housing 46. The lower end side of the valve stem 52 is similarly supported by the valve shaft body housing 46 by a bearing.

  As shown in FIG. 4, one end of a lid (valve body) 55 is attached to the sprocket 47, and the other end of the lid 55 is attached to the other end of the sprocket 48. The lid portion 55 has a main body portion 55a having a substantially U-shaped cross section and a pair of attachment portions 55b continuous to the main body portion 55a. The lid portion 55 is attached to the sprockets 47 and 48 by the attachment portions 55b, respectively. ing. The first coal supply pipe 21 is opened and closed by the lid portion 55.

  FIG. 4 shows a state in which the first coal supply pipe 21 is closed by the lid portion 55 (this state is referred to as a closed position), and a state in which the first coal supply pipe 21 is opened from the closed position (this state is opened). 3), the motor 25 shown in FIG. 3 is rotationally driven, and this rotational force is transmitted to the sprocket 45 via the roller chain. As described above, since the sprocket 45 is fitted into the valve stem 52, the valve stem 52 is rotated by the rotation of the sprocket 45.

  Since the sprockets 47 and 48 are fitted into the valve stem 52, the sprockets 47 and 48 are rotated by the rotation of the valve stem 52, whereby the lid portion 55 attached to the sprockets 47 and 48 is changed from the closed position to the open position. Move towards. FIG. 3 is a view showing a state where the first coal supply pipe 21 is opened. In FIG. 3, the lid portion 55 is housed in the right side portion of the housing 40, and the first coal supply pipe 21 is shown. Is released.

  When moving the lid portion 55 from the open position to the closed position, for example, the motor 25 is reversed. As a result, when the valve stem 52 rotates in the reverse direction and reversely rotates from the open position to the closed position, the lid portion 55 is in the state shown in FIG. 4, and the first coal supply pipe 21 is closed by the lid portion 55.

  Here, referring to FIG. 5, the above-described call gate valve 22 (that is, the motor 25), the coal feeder 23 (that is, the motor 28), and the mill 12 are driven and controlled by the control device 31. For example, as will be described later, the control device 31 drives and controls the call gate valve 22, the coal feeder 23, and the mill 12 in accordance with the on / off of the operation switch 32. The control device 31 has a built-in timer (not shown) and is given a rotational speed of the conveyor belt 26. Further, in the control device 31, the relationship between the rotation speed of the motor 28, that is, the rotation speed of the conveyor belt 26 and the amount of coal supplied to the mill 12 (per unit time) is set in advance as a speed-coal amount table. Yes.

  Further, although not shown in FIG. 5, the detection output of the limit switch 25a (on / off output: the limit switch 25a is turned on when the motor 25 is in the open position or the closed position) is given to the control device 31. When the cover unit 55 is moved from the open position to the closed position and from the closed position to the open position, the control device 31 stops the motor 25 when the limit switch 25a is turned on again.

  Referring to FIG. 6 in addition to FIGS. 2 and 5, it is assumed that the operation switch 32 is now in an ON state. At this time, the call gate valve 22 is in an open state (open position), and the coal feeder 23, that is, the conveyor belt 26 is rotationally driven by a motor 28 at a speed (constant speed) defined in advance. An amount (fixed amount) of coal corresponding to the constant speed is supplied to the mill 12 through the second coal supply pipe 24 per unit time. In addition, the mill 12 is also in an on state, and the coal supplied from the coal feeder 23 is finely pulverized into pulverized coal.

Now, at time t ₁ shown in FIG. 6, when the operation switch 32 is switched from ON and OFF (OFF), off of the operation switch 32 is detected by the control device 31. When detecting that the operation switch 32 is turned off, the control device 31 controls the coal feeder 23, that is, controls the motor 28 to gradually decrease the rotation speed of the conveyor belt 26 from the constant speed state.

Then, the rotational speed (zero <predetermined rotational speed <constant speed) at time t _2, which reaches a predetermined rotational speed (predetermined speed lower than the constant speed) of the conveyor belt 26, the control device 31 the motor 25 Is driven to move the call gate valve 22 in the closing direction, and the first coal supply pipe 21 is closed. That is, the controller 31 after detecting the off operation switch 32 at time t _1, the from constant speed rotation speed of the conveyance belt 26 at time (t 2 _{-t 1)} and a predetermined speed.

Further, when the time (t ₂ −t ₁ ) has elapsed (when the rotation speed of the conveyor belt 26 reaches a predetermined rotation speed (for example, counting with a built-in timer)), the control device 31 includes the motor 25. Is controlled so as to close the first coal supply pipe 21 (the closing time of the call gate valve 22 is, for example, about 10 seconds). At this time, the control device 31 maintains the rotation speed of the conveyor belt 26 at the predetermined rotation speed described above.

After operating the call gate valve 22 in the closing direction and closing the first coal supply pipe 21, the control device 31 sets a preset time ta (for example, any time from 1 minute to 2 minutes: first When 1 time) has elapsed (the time t ₃ the time), it stops the rotation of the conveyor belt 26 the motor 28 stop control to. Thereafter, when a predetermined time tb (second time) elapses (time t ₄ ), the control device 31 stops (turns off) the mill 12.

  As described above, when the operation switch 32 is turned off, the control device 31 first reduces the rotation speed of the conveyor belt 26 to a predetermined rotation speed less than a constant speed. In other words, the rotational speed of the conveyor belt 26 is decreased, the amount of coal supplied to the mill 12 per unit time is reduced, and an amount (predetermined amount) of coal corresponding to the predetermined rotational speed of the conveyor belt 26 is milled. 12 will be supplied.

  Subsequently, the control device 31 operates in a direction to close the call gate valve 22 to close the first coal supply pipe 21, and stops the supply of coal from the coal bunker 11 to the coal feeder 23. At this time, the coal on the conveyor belt 26 is supplied to the mill 12 via the second coal supply pipe 24 in accordance with the rotation of the conveyor belt 26 (predetermined rotation speed), and the coal is supplied below the coal gate valve 22. The coal present in one coal supply pipe 21 is gradually supplied onto the conveyor belt 26.

  Then, after the call gate valve 22 is closed (that is, after the first coal supply pipe 21 is closed), when the set time ta (first time) elapses, the control device 31 stops the rotation of the conveyor belt 26. To do. Here, the set time ta is, for example, the time until all the coal present in the first coal supply pipe 21 is supplied onto the conveyor belt 26 at least below the coal gate valve 22. That is, the set time ta is equal to the rotational speed of the conveyor belt 26 (the predetermined rotational speed described above) and the amount of coal present in the first coal supply pipe 21 below the coal gate valve 22 (that is, the coal gate valve 22). The internal volume of the first coal supply pipe 21 from the outlet to the outlet of the first coal supply pipe 21).

  Subsequently, when the time tb (second time) elapses after the rotation of the conveyor belt 26 is stopped, the control device 31 stops the mill 12 (for example, supplied from the conveyor belt 26 to the mill 12). The mill 12 is stopped after the coal is pulverized).

  As described above, when the operation switch 32 is turned off, coal is not retained between the conveyor belt 26 and the coal gate valve 22. Therefore, even if the mill 12 is stopped for a long time, Since there is no coal in the first coal supply pipe 21 below the gate valve 22, coal clogging resulting from being left for a long period of time is caused between the coal gate valve 22 and the conveyor belt 26. It does not occur in the first coal supply pipe 21 located at the position.

When resuming the operation of the mill 12, the operation switch 32 is turned on (the time to t _5). When detecting that the operation switch 32 is turned on, the control device 31 first turns on (drives) the mill 12. After the operation switch 32 is turned on, a predetermined time tc (third time) has elapsed (for the time and t _6), the controller 31 rotates the transport belt 26 by driving the motor 28 Then, the rotational speed is gradually increased to a constant speed state.

When the rotational speed of the conveyance belt 26 becomes a time instant t ₇ is the time after a constant speed, the control device 31 operates the call gate valve 22 in an opening direction, opening the first coal feed pipe 21 . That is, after the predetermined time tc has elapsed, further, the time _(t 7 -t ₆₎ has elapsed (time _(t 7 -t ₆₎ is a fourth time. Here, the time _(t 7 -t ₆ ), the control device 31 sets the speed of the conveying belt 26 to a constant speed), and the control device 31 operates the call gate valve 22 in the opening direction to open the first coal supply pipe 21 (this fourth feed). The time is at least the time from when the conveyor belt 26 is driven until the rotational speed of the conveyor belt 26 reaches a constant speed).

  Thus, when the operation switch 32 is turned on, the control device 31 first starts driving the conveyor belt 26 after a predetermined time tc (third time) has elapsed after the mill 12 is turned on. . Therefore, if coal remains in the mill 12, the remaining coal is finely pulverized. If coal remains on the conveyor belt 26, the remaining coal is supplied to the mill 12 via the second coal supply pipe 24 by the rotation of the conveyor belt 26. After the rotational speed of the conveyor belt 26 reaches a constant speed, the coal gate valve 22 is driven in the opening direction to open the first coal supply pipe 21 and supply coal to the coal feeder 23, that is, the conveyor belt 26. Therefore, even when the operation is resumed after the mill 12 has been stopped for a long time, the coal can be stably supplied to the mill 12. That is, pulverized coal can be stably supplied as fuel to the boiler device 13 without any trouble.

  As is clear from the above description, in this embodiment, the control device 31 has functions as first to sixth control means. Moreover, in the above-described embodiment, the coal-fired power plant using pulverized coal as a fuel has been exemplified. Can be used.

  The above-described control may be performed by a control program that runs on a computer such as a microprocessor. In other words, the control device 31 that is a microprocessor may operate a pulverized coal supply control program, and the above-described various controls may be executed by the pulverized coal supply control program.

It is a figure which shows roughly the principal part of the coal-fired power plant in which an example of the pulverized coal supply apparatus by embodiment of this invention is used. It is a figure which shows an example of the pulverized coal supply apparatus by embodiment of this invention. It is the figure seen from the upper side in the state which fractured | ruptured partially the call gate valve shown in FIG. 2, and opened the 1st coal supply pipe | tube. It is sectional drawing which shows the state which closed the 1st coal supply pipe | tube in the AA line cross section of FIG. It is a block diagram which shows the control system of the pulverized coal supply apparatus shown in FIG. 6 is a timing chart for explaining the operation of the control device shown in FIG. 5.

Explanation of symbols

11 Coal bunker 12 mil (pulverized coal machine)
21, 24 Coal supply pipe 22 Cole gate valve (valve mechanism)
23 Coal feeder 25, 28 Motor 26 Conveying belt 27a Driven roller 27b Drive roller 31 Controller

Claims (7)

Finely pulverizing coal into pulverized coal and supplying it as a fuel to a boiler unit, a coal bunker for storing the coal and supplying the coal to the pulverized coal machine, the pulverized coal machine, and the A coal supply passage disposed between the coal bunker and the coal bunker for adjusting the amount of coal supplied from the coal bunker to the pulverized coal machine, and extending from the coal bunker to the coal feeder A pulverized coal supply device provided with a valve mechanism for opening and closing the coal supply passage,
A first control means for stopping the coal feeder when a predetermined first time has elapsed after closing the coal feeding passage by the valve mechanism;
Second control means for stopping the pulverized coal machine when a second time has elapsed after stopping the coal feeder ;
Et al is a third control means for operating the switch to reduce gradually the amount of coal supplied from said stoker and turned off in the coal pulverizer,
Fourth control means for closing the coal supply passage by the valve mechanism when the amount of coal supplied from the coal feeder to the pulverized coal machine is reduced to a predetermined amount;
A pulverized coal supply apparatus characterized by comprising: The coal feeder receives the coal from an outlet of the coal supply passage, and conveys the coal to an inlet side of the pulverized coal machine;
Drive means for driving the carrier,
2. The pulverized coal supply according to claim 1, wherein the third control unit gradually decelerates the carrier from a predetermined constant speed to a predetermined speed corresponding to the predetermined amount. apparatus. The first time, according to claim 2, characterized in that the moving speed of the transfer member from the valve mechanism to be determined according to the volume of the coal feed passage to the outlet of the coal feed passage The pulverized coal supply device described. When restarting the operation after stopping the pulverized coal machine, a fifth control means for driving the coal feeder when a third time has elapsed after driving the pulverized coal machine;
A sixth control means for opening the coal supply passage by the valve mechanism when a fourth time has elapsed after driving the coal feeder;
The pulverized coal supply device according to claim 1, wherein When restarting the operation after stopping the pulverized coal machine, after driving the pulverized coal machine, a fifth control means for driving the carrier when a third time has elapsed;
And a sixth control means for opening the coal supply passage by the valve mechanism when a fourth time has elapsed after driving the carrier,
4. The pulverized coal supply apparatus according to claim 2, wherein the fourth time is at least a time until the speed of the transport body reaches a constant speed after driving the transport body. Finely pulverizing coal into pulverized coal and supplying it as a fuel to a boiler unit, a coal bunker for storing the coal and supplying the coal to the pulverized coal machine, the pulverized coal machine, and the A coal supply passage disposed between the coal bunker and the coal bunker for adjusting the amount of coal supplied from the coal bunker to the pulverized coal machine, and extending from the coal bunker to the coal feeder And a control method for controlling the supply of the pulverized coal, which is used in a pulverized coal supply device provided with a valve mechanism for opening and closing the coal supply passage.
A first step of driving and controlling the valve mechanism to close the coal supply passage;
A second step of stopping the coal feeder when a predetermined first time has elapsed after closing the coal feeding passage;
A third step of stopping the pulverized coal machine when a second time has elapsed after stopping the coal feeder;
Furthermore, when the operation switch is turned off, a fourth step of gradually reducing the amount of coal supplied from the coal feeder to the pulverized coal machine;
A fifth step of closing the coal supply passage by the valve mechanism when the amount of coal supplied from the coal feeder to the pulverized coal machine is reduced to a predetermined amount;
A pulverized coal supply control method characterized by comprising: Finely pulverizing coal into pulverized coal and supplying it as a fuel to a boiler unit, a coal bunker for storing the coal and supplying the coal to the pulverized coal machine, the pulverized coal machine, and the A coal supply passage disposed between the coal bunker and the coal bunker for adjusting the amount of coal supplied from the coal bunker to the pulverized coal machine, and extending from the coal bunker to the coal feeder A control program for controlling the supply of the pulverized coal, used in a pulverized coal supply device provided with a valve mechanism for opening and closing the coal supply passage,
On the computer,
A first step of driving and controlling the valve mechanism to close the coal supply passage;
A second step of stopping the coal feeder when a predetermined first time has elapsed after closing the coal feeding passage;
A third step of stopping the pulverized coal machine when a second time has elapsed after stopping the coal feeder;
A fourth step of gradually reducing the amount of coal supplied from the coal feeder to the pulverized coal machine when the operation switch is turned off;
A fifth step of closing the coal supply passage by the valve mechanism when the amount of coal supplied from the coal feeder to the pulverized coal machine is reduced to a predetermined amount;
A pulverized coal supply control program characterized in that

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