JP5710149B2 - Coal grinding method - Google Patents

Description

  The present invention relates to a method for pulverizing coal into pulverized coal.

  Conventionally, a pulverized coal combustion apparatus such as a boiler using pulverized coal obtained by pulverizing coal as a fuel is known. Generally, a pulverized coal combustion apparatus includes a coal pulverizer (coal mill) that pulverizes coal supplied to the inside and continuously transports the pulverized coal to the outside. The pulverized coal combustion apparatus has a cold air damper and a hot air damper for supplying hot air for drying the pulverized coal to the inside of such a coal pulverizer, and the internal temperature is increased by adjusting the internal temperature. Suppresses the ignition of coal caused by

  There exists invention of patent document 1 as what prevents the ignition of coal by controlling such a cold air damper and a hot air damper. Patent Document 1 discloses a coal mill temperature monitoring system that detects the temperature of the hot air supply port and keeps the temperature of the pulverized coal transport port constant, thereby preventing the ignition of coal inside the coal pulverizer. Yes.

JP 60-122059 A

  By the way, as coal used for such pulverized coal combustion addition, low-grade coal such as sub-bituminous coal and lignite having a lower carbon content than commonly used high-grade coal such as bituminous coal, It is also attracting attention in terms of demand expansion and cost.

  However, low-grade coal has a lower ignition temperature than high-grade coal and has a characteristic of being easily ignited. Therefore, as in Patent Document 1, in the method of controlling the temperature of the hot air supply port and keeping the temperature of the pulverized coal transport port constant, the state change of the coal in the coal pulverizer cannot be detected, and the low-grade coal is spontaneously ignited. There was a problem that it could not be suppressed.

  Then, the objective of this invention is providing the coal grinding | pulverization method which can suppress the ignition of a low grade coal.

The present invention is a coal pulverization method for pulverizing low-grade coal supplied to a coal pulverizer into pulverized coal and transporting the pulverized coal from a pulverized coal outlet to a pulverized coal combustion apparatus, wherein hot air is supplied to the coal pulverizer. A step of drying the crushed low-grade coal , a step of measuring CO concentration at the outlet of the pulverized coal and detecting CO, and the coal according to the detected CO concentration of CO. By reducing the flow rate of the hot air supplied to the inside of the pulverizer, the amount of heat of the hot air is reduced, and the amount of the low-grade coal to be supplied is reduced according to the reduced amount of heat of the hot air. And pulverized coal obtained by pulverizing high-grade coal is supplied to the pulverized coal combustion apparatus according to the reduced amount of the low-grade coal .

  Generally, coal is thermally decomposed by heating. When pyrolysis is started, CO gas and the like are released from the coal. Thereafter, the coal is ignited before and after the release of volatile components from the coal. According to the above configuration, the CO concentration is measured at the pulverized coal outlet of the coal pulverizer to grasp the state of the coal in the coal pulverizer, and the amount of hot air supplied to the coal pulverizer is reduced according to the CO concentration. I do. Thereby, the state of coal in the coal pulverizer can be grasped from the CO concentration, the amount of heat applied to the inside of the coal pulverizer can be reduced, and the temperature inside the coal pulverizer can be reduced. As a result, since the state of the coal in the coal pulverizer is grasped and the ignition is prevented in advance, the ignition can be suppressed even if the coal is easily spontaneously ignited such as low-grade coal.

Moreover , the supply amount of coal is reduced according to the heat quantity of the reduced hot air. Thereby, the calorie | heat amount of the hot air which dries coal can be reduced, and it can prevent that the moisture content contained in the pulverized coal manufactured increases.

It is explanatory drawing which shows the example of application of the coal pulverization system which performs a coal pulverization method. It is explanatory drawing which shows a CO analyzer. The figure which shows the flowchart of a control routine at the time of abnormality. The figure which shows the flowchart of a control routine at the time of a return.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings.

(Constitution)
FIG. 1 is an explanatory view showing an embodiment to which a coal crushing system for executing the coal crushing method of the present invention is applied. As shown in FIG. 1, coal C is supplied from the outside to the coal crushing system 100 and cold air and hot air are introduced. As a result, the coal pulverization system 100 is configured to transport the pulverized coal W to the outside as fuel such as a boiler.

  Specifically, the configuration of the coal crushing system 100 will be described. The coal pulverization system 100 includes a coal feeder 6, a coal pulverizer 1, a pulverized coal outlet pipe 9, a cold air damper 4, a hot air damper 5, a hot air supply line 10, a CO analyzer 2, A charcoal outlet temperature detector 7 and a control unit 3 are provided.

(Coal feeder 6)
The coal feeder 6 has a function of supplying a constant amount of coal into the coal crusher 1. Specifically, the coal feeder 6 has a coal bunker 6a, a transport unit 6b, and a discharge unit 6c. The coal bunker 6a temporarily stores massive coal C that is a raw material for pulverized coal. The transport unit 6b includes, for example, a transport unit that transports the coal C such as a belt conveyor to the discharge unit 6c, and a detection unit that detects the weight of the coal C on the transport unit (not shown). Thereby, the conveyance part 6b can convey the fixed amount of coal C per speed to the discharge part 6c. Further, the transport unit 6 b is electrically connected to the control unit 3. The transport speed of the coal C is controlled by the control signal from the control unit 3 in the transport unit 6b. Thereby, supply_amount | feed_rate of the coal C which the coal feeder 6 supplies to the coal grinder 1 can be changed now. The discharge unit 6 c is a communication pipe that communicates with the inside of the coal pulverizer 1.

  The coal C supplied to the coal pulverizer 1 is particularly targeted for so-called low-grade coal such as subbituminous coal and lignite. Low-grade coal has a lower ignition temperature and is more likely to spontaneously ignite than so-called high-grade coal such as bituminous coal.

(Cold air damper 4, hot air damper 5, hot air supply line 10)
The cold air damper 4 is an electric valve that adjusts the supply amount of low-temperature cold air introduced from the outside. The hot air damper 5 is an electric valve that adjusts the supply amount of hot hot air introduced from the outside. The cold air damper 4 and the hot air damper 5 are electrically connected to the control unit 3, and their opening degrees are adjusted by a control signal from the control unit 3. The hot air supply line 10 is a pipe that joins the cold air from the cold air damper 4 and the hot air from the hot air damper 5 into hot air A and supplies the hot air A to the coal pulverizer 1.

(Coal crusher 1)
The coal pulverizer 1 is provided below the coal feeder 6. The coal pulverizer 1 includes a coal inlet 1a, a pulverizing table 1b, a pulverizing roller 1c, and a motor 1d. The coal inlet 1 a is an opening that penetrates through the upper part of the coal pulverizer 1, and the discharge part 6 c of the coal feeder 6 is inserted therethrough. The crushing table 1b is disposed below the coal inlet 1a inside the coal crusher 1. The crushing table 1b has a disk shape and is disposed so as to divide the inside of the coal crusher 1 into upper and lower atmospheres. The lower surface of the crushing table 1b is fixed by an axle, and can be rotated in the horizontal direction. A plurality of crushing rollers 1c are arranged in an annular shape so as to come into contact with the outer peripheral edge region of the upper surface of the crushing table 1b. The crushing roller 1c is fixed by an axle, and can rotate while being in contact with the upper surface of the crushing table 1b. The motor 1d transmits power to the respective axles of the crushing table 1b and the crushing roller 1c. In other words, the pulverization table 1b and the pulverization roller 1c are driven to rotate by being contacted with the power transmitted by the motor 1d.

  Moreover, the coal pulverizer 1 has a hot air inlet 1e and a pulverized coal outlet 1f. The hot air inlet 1e is an opening provided in the lower atmosphere divided by the crushing table 1b. The hot air inlet 1e is communicated with the hot air supply line 10 and hot air from the hot air supply line 10 is introduced. The pulverized coal outlet 1 f is an opening provided in the upper part of the coal pulverizer 1. The pulverized coal outlet 1 f communicates with the pulverized coal outlet pipe 9, and the pulverized coal W is transported to the pulverized coal outlet pipe 9.

(Pulverized coal outlet pipe 9)
The pulverized coal outlet pipe 9 is a pipe provided at the pulverized coal outlet 1f. In the pulverized coal outlet pipe 9, the hot air A from the coal pulverizer 1 and the pulverized coal W conveyed by the hot air A transport the pulverized coal outlet 1 f to the outside.

(Pulverized coal outlet temperature detector 7)
The pulverized coal outlet temperature detector 7 detects the temperature of the primary air in the pulverized coal outlet pipe 9. The pulverized coal outlet temperature detector 7 is electrically connected to the control unit 3 and outputs a signal including detected temperature information to the control unit 3.
(Control unit 3)

  The control unit 3 has a function of outputting a signal for controlling the supply amount of the coal C to the coal pulverizer 1 to the coal feeder 6. Further, the control unit 3 has a function of outputting a signal for controlling the temperature and flow rate of the hot air A introduced into the coal pulverizer 1 to the cold air damper 4 and the hot air damper 5. Further, the control unit 3 has a function of controlling the amount of heat of the hot air A introduced into the coal pulverizer 1 so that the temperature detected by the pulverized coal outlet temperature detector 7 is 70 to 80 ° C.

  The control unit 3 includes a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), and the like as hardware configurations. The ROM is a read-only storage device that stores various programs used to execute the functions described above. The CPU performs various operations and processes based on various received signals and various programs stored in the ROM, and transmits and receives signals and data to and from other controllers. The RAM is a readable / writable volatile storage device, and stores various calculation results in the CPU. By combining these hardware and software, the functions as described above are executed.

(CO analyzer 2)
The CO analyzer 2 is provided in the pulverized coal outlet pipe 9 and has a function of measuring the concentration of CO contained in the hot air A in the pulverized coal outlet pipe 9. Here, the CO analyzer 2 will be described in detail with reference to FIG. As shown in FIG. 2, the CO analyzer 2 includes a bag filter 20, a differential pressure gauge 21, an analysis air damper 22, an analyzer 23, a control unit 24, and a compressed air valve 25.

  The bag filter 20 has a double tube structure in which a cylindrical filter with both ends closed is provided inside a cylinder with both ends closed. That is, the bag filter 20 has an external space (external space 20a) of the filter and an internal space (internal space 20b) of the filter. Both ends of the bag filter 20 are communicated with the pulverized coal outlet pipe 9, and the hot air A introduced from one end is discharged to the other end.

  The differential pressure gauge 21 is a detector that detects a pressure difference between the external space 20a and the internal space 20b. That is, the pressure difference between the external space 20a and the internal space 20b generated by the filter being clogged is detected. The differential pressure gauge 21 is electrically connected to the control unit 24, and outputs a signal including information on the detected pressure difference between the external space 20a and the internal space 20b to the control unit 24 at a predetermined interval. ing.

  The analysis air damper 22 is an electric valve that adjusts the flow rate of the hot air A introduced into the analyzer 23. The analysis air damper 22 and the control unit 24 are electrically connected, and the opening degree is controlled by a control signal from the control unit 24. The compressed air valve 25 is an electromagnetic valve that opens and closes a line for introducing compressed air from the outside to the internal space 20b. The compressed air valve 25 is electrically connected to the control unit 24, and switching between opening and closing is controlled by a control signal from the control unit 24.

  The analyzer 23 is a detector that measures the CO concentration contained in the hot air A introduced through the analysis air damper 22. The analyzer 23 is electrically connected to the control unit 24 and outputs a signal including information on the detected CO concentration to the control unit 24 at a predetermined interval.

  The control unit 24 has a function of outputting a signal for adjusting the opening degree to the analysis air damper 22. The control unit 24 has a function of performing opening / closing control of the compressed air valve 25 based on a signal from the differential pressure gauge 21. The control unit 24 has a function of outputting a signal including information on the CO concentration to the control unit 3 based on a signal from the analyzer 23.

  The control unit 24 includes a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), and the like as hardware configurations. The ROM is a read-only storage device that stores various programs used to execute the functions described above. The CPU performs various operations and processes based on various received signals and various programs stored in the ROM, and transmits and receives signals and data to and from other controllers. The RAM is a readable / writable volatile storage device, and stores various calculation results in the CPU. By combining these hardware and software, the functions as described above are executed. The control unit 24 may be configured as a single unit with the control unit 3.

(Second coal grinding system 200, pulverized coal combustion device 300)
The pulverized coal transported to the outside is supplied to the pulverized coal combustion apparatus 300 such as a boiler. In addition, a pulverized coal supply line from the second coal pulverization system 200 different from the coal pulverization system 100 is connected to the pulverized coal supply line to the pulverized coal combustion apparatus 300. The second coal pulverization system 200 pulverizes high-grade coal such as bituminous coal and supplies pulverized coal. Thereby, when the supply of pulverized coal to the pulverized coal combustion apparatus 300 is insufficient, the second coal pulverization system 200 can reliably make up.

(Operation)
Operation | movement of the coal grinding | pulverization system 100 comprised in this way is demonstrated.

(Coal supply process)
First, the coal supply process of the coal crushing system 100 will be described. The coal feeder 6 supplies the coal C to the coal crusher 1 based on a control signal including supply amount command information from the control unit 3. Here, the supply amount command information is a signal indicating the supply amount of coal C per hour. Specifically, the transport unit 6b changes the transport speed while detecting the weight of the coal C to be placed, and transports a fixed amount of coal C to the discharge unit 6c. And the coal C conveyed to the discharge part 6c is supplied to the inside of the coal grinder 1 through the discharge part 6c.

(Coal crushing process)
Next, the coal grinding process of the coal grinding system 100 will be described. Coal C supplied from the discharge unit 6c of the coal feeder 6 is input from the coal input port 1a and dropped onto the upper surface of the crushing table 1b. The coal C on the crushing table 1b is sent out in the direction of the outer peripheral edge by centrifugal force when the crushing table 1b is driven to rotate. The coal C fed to the outer peripheral area is pulverized by applying pressure between the pulverizing table and the pulverizing roller.

(Hot air introduction process)
Next, the hot air introduction process of the coal crushing system 100 will be described. The cold air damper 4 and the hot air damper 5 supply hot air A to the coal pulverizer 1 based on a control signal including an opening adjustment signal from the control unit 3. Here, the opening degree adjustment signal is a signal indicating how much the cold air damper 4 and the hot air damper 5 are opened. Thereby, the flow volume of the cold air and hot air which are introduce | transduced is adjusted. Then, the hot air supply line 10 joins the introduced cold air and hot air into the hot air A and introduces it into the coal pulverizer 1.

(Coal drying process, pulverized coal transport process)
Next, the hot air introduction process and the pulverized coal transport process of the coal crushing system 100 will be described. The hot air introduced from the hot air introduction port 1e is supplied to the upper atmosphere inside the coal pulverizer 1 through a large number of ejection holes (not shown) on the radially outer side of the pulverization table 1b. Thereby, the hot air A dries the coal C. Moreover, the hot air A conveys the pulverized coal C upward while drying. Coarse particles in the coal C to be transported are separated from the hot air A as the flow rate of the hot air A is reduced, and dropped onto the pulverizing table 1b again and pulverized. On the other hand, of the coal C conveyed upward by the hot air A, the one not separated from the hot air A is transported as pulverized coal W to the pulverized coal outlet pipe 9 through the pulverized coal outlet 1f.

(CO concentration detection process)
Next, the CO concentration detection process of the coal pulverization system 100 will be described. As shown in FIG. 2, the CO analyzer 2 takes hot air A into the external space 20 a of the bag filter 20 by the bag filter 20. The taken-in hot air A passes through the filter, and the contained pulverized coal is removed and enters the internal space 20b. The hot air A in the internal space 20 b is collected by the analyzer 23 through the analysis air damper 22 whose opening degree is adjusted by the control unit 24. The analyzer 23 analyzes the collected hot air A to detect the CO concentration, and outputs a CO concentration signal including the information to the control unit 3 via the control unit 24.

  Further, when the bag filter 20 is clogged, the bag filter 20 is backwashed. Specifically, the control unit 24 determines that the bag filter 20 is clogged when the pressure difference from the differential pressure gauge 21 is equal to or greater than a predetermined value. That is, when pulverized coal W is clogged in the filter in the bag filter 20, the hot air A is hardly passed from the external space 20a to the internal space 20b, and a pressure difference is generated between the two spaces. When a pressure difference equal to or greater than a predetermined value occurs, the control unit 3 energizes the compressed air valve 25 to open the compressed air valve 25. The compressed air passes from the internal space 20b to the external space 20a. Thereby, the pulverized coal clogging the bag filter 20 is removed, and stable CO concentration detection can be performed. The removed pulverized coal is returned to the pulverized coal outlet pipe 9 and transported.

(Control process for abnormal conditions)
Next, an abnormality control routine executed by the control unit 3 of the coal crushing system 100 when the CO analyzer 2 detects CO in the hot air A will be described with reference to FIG. FIG. 3 is a flowchart of the abnormal time control routine.

  First, the control unit 3 determines whether or not a CO concentration signal has been received from the CO analyzer 2 (S10). When the CO concentration signal is not received (S10: NO), the process returns to step S10. That is, the CO concentration signal is on standby. On the other hand, when the CO concentration signal is received (S10: YES), it is determined whether or not the CO concentration is abnormal (S20). Specifically, in this embodiment, a case where the CO concentration exceeds a predetermined threshold is determined as abnormal. That is, when the CO concentration exceeds a predetermined threshold value, it is determined that the thermal decomposition of the coal C inside the coal pulverizer 1 proceeds and the CO released from the coal C is excessive.

  If the CO concentration does not exceed the predetermined threshold, that is, if the CO concentration is not abnormal (S20: NO), the process returns to step S10. On the other hand, when the CO concentration exceeds a predetermined threshold value, that is, when the CO concentration is abnormal (S20: YES), the cold air damper 4 and the hot air damper 5 are controlled, and the coal pulverizer 1 While reducing the calorie | heat amount of the hot air introduce | transduced in, the amount of coal C which the coal feeder 6 supplies quantitatively is reduced (S30).

  Here, “decreasing the amount of heat of hot air” means the following. For example, the control unit 3 outputs a control signal that increases the opening degree of the cold air damper 4 and decreases the opening degree of the hot air damper 5. Thereby, the temperature of the hot air is lowered to reduce the amount of heat. For example, the control unit 3 outputs a control signal for reducing the opening of the cold air damper 4 and the opening of the hot air damper 5. As a result, the amount of heat is reduced by decreasing the flow rate of hot air. Note that the present invention is not limited to such a method, and both of them may be performed, or the amount of heat of hot air may be reduced by other methods.

  Further, the control unit 3 outputs a control signal for reducing the fixed supply amount of coal C to the transport unit 6 b of the coal feeder 6. Thereby, it is possible to prevent the amount of heat contained in the produced pulverized coal from being increased by reducing the amount of heat for drying the coal C by executing step S30.

  The hot air heat quantity lowering process and the supply quantity reducing process in step S30 are performed simultaneously so that the temperature detected by the pulverized coal outlet temperature detector 7 is within a predetermined temperature range (70 to 80 ° C. in the present embodiment). Although it is preferable, it is not limited to this. For example, the supply amount of coal C may be reduced after the amount of hot air is reduced. Thereby, the state with few coal C in the coal grinder 1 with respect to the calorie | heat amount of a hot air can be avoided. That is, it is possible to prevent the coal C from being ignited by avoiding a state where the total amount of water contained in the coal C in the coal pulverizer 1 is reduced.

  Although not shown, the control unit 3 outputs a pulverized coal supply command to the second coal crushing system 200 after the end of this routine. Thereby, even if it is a case where the quantity of pulverized coal W which coal pulverization system 100 transports is decreased by execution of this routine, the 2nd coal pulverization system 200 supplies pulverized coal, so that pulverized coal combustion device The load at 300 can be supplemented.

  As described above, the coal pulverization method of the present embodiment is a coal pulverization method in which coal C supplied to the coal pulverizer 1 is pulverized into pulverized coal W, and the pulverized coal W is transported from the pulverized coal outlet pipe 9. The hot air A is supplied to the inside of the coal pulverizer 1, the pulverized coal C is dried, the pulverized coal outlet pipe 9 measures the CO concentration and detects CO, and the detected CO And a step of performing control to reduce the amount of heat of the hot air A supplied to the inside of the coal pulverizer 1 in accordance with the CO concentration.

  Thereby, the state of the coal C in the coal pulverizer 1 can be grasped from the CO concentration, the amount of heat applied to the inside of the coal pulverizer can be reduced, and the temperature inside the coal pulverizer 1 can be reduced. As a result, since the state of the coal in the coal pulverizer 1 is grasped and ignition is prevented in advance, even if the coal is likely to spontaneously ignite, such as low-grade coal, ignition can be suppressed.

  In the coal pulverization method of the present embodiment, the amount of coal to be supplied is reduced in accordance with the reduced temperature of the hot air A. I am letting. Thereby, the calorie | heat amount of the hot air A which dries coal can be reduced, and it can prevent that the moisture content contained in the pulverized coal W manufactured is increased.

(Return control process)
Next, a return control routine after the abnormal control routine executed by the control unit 3 of the coal crushing system 100 will be described with reference to FIG. FIG. 4 is a flowchart of the return control routine.

  First, the control unit 3 determines whether or not a CO concentration signal has been received from the CO analyzer 2 (S110). When the CO concentration signal is not received (S110: NO), the process returns to step S110. That is, the CO concentration signal is on standby. On the other hand, when the CO concentration signal is received (S110: YES), it is determined whether or not the CO concentration indicates a safe region (S120). Specifically, in the present embodiment, a case where the CO concentration is equal to or less than the predetermined threshold is determined as the safe region. Note that the CO concentration that is the safe region is not limited to this. Then, the amount of coal C supplied by the coal feeder 6 is increased, and the amount of hot air is increased (S130).

  Specifically, the control unit 3 outputs a control signal for reducing the fixed supply amount of coal C to the transport unit 6 b of the coal feeder 6. Thereby, it is possible to prevent the amount of heat contained in the produced pulverized coal from being increased by reducing the amount of heat for drying the coal C by executing step S30.

  Further, “increasing the amount of heat of hot air” means the following. For example, the control unit 3 outputs a control signal that decreases the opening degree of the cold air damper 4 and increases the opening degree of the hot air damper 5. As a result, the amount of heat is increased by increasing the temperature of the hot air. For example, the control unit 3 outputs a control signal for increasing the opening degree of the cold air damper 4 and the opening degree of the hot air damper 5. This increases the amount of heat by increasing the flow rate of hot air. Note that the present invention is not limited to such a method, and both of them may be performed, or the amount of heat of hot air may be increased by other methods.

  The step of increasing the amount of hot air in step S130 and the step of increasing the supply amount are performed simultaneously so that the temperature detected by the pulverized coal outlet temperature detector 7 is within a predetermined temperature range (70 to 80 ° C. in the present embodiment). Although it is preferable, it is not limited to this. For example, after increasing the supply amount of coal C, the heat amount of hot air may be increased. Thereby, the state with few coal C in the coal grinder 1 with respect to the calorie | heat amount of a hot air can be avoided. That is, it is possible to prevent the coal C from being ignited by avoiding a state where the total amount of water contained in the coal C in the coal pulverizer 1 is reduced.

  Although not shown, the control unit 3 outputs a pulverized coal supply stop command to the second coal pulverization system 200 after the end of this routine. Thereby, supply of pulverized coal by the 2nd coal crushing system 200 can be stopped, and it can switch to only supply of pulverized coal by the coal crushing system 100. As a result, the amount of high-grade coal used for the fuel coal can be reduced, and the cost can be reduced.

(Modification)
The embodiments of the present invention have been described above, but only specific examples have been illustrated, and the present invention is not particularly limited. Specific configurations and the like can be appropriately changed in design. Further, the actions and effects described in the embodiments of the present invention only list the most preferable actions and effects resulting from the present invention, and the actions and effects according to the present invention are described in the embodiments of the present invention. It is not limited to things.

  In the present embodiment, the differential pressure gauge 21 that detects the pressure difference is used to determine whether the bag filter 20 is clogged. However, the present invention is not limited to this. For example, the control unit 3 may open the compressed air valve 25 every predetermined time and backwash the bag filter 20 with the compressed air.

DESCRIPTION OF SYMBOLS 1 Coal crusher 1a Coal inlet 1b Crushing table 1c Crushing roller 1d Motor 1e Hot air inlet 1f Pulverized coal outlet 2 CO analyzer 3 Control unit 4 Cold air damper 5 Hot air damper 6 Coal feeder 6a Coal bunker 6b Carrying part 6c Discharge unit 7 Pulverized coal outlet temperature detector 9 Pulverized coal outlet pipe 10 Hot air supply line 20 Bag filter 20a External space 20b Internal space 21 Differential pressure gauge 22 Analytical air damper 23 Analyzer 24 Control unit 25 Compressed air valve 100 Coal crushing system 200 2 Coal crushing system 300 Pulverized coal combustor C Coal W Pulverized coal A Hot air

Claims (1)

A coal pulverization method for pulverizing low-grade coal supplied to a coal pulverizer into pulverized coal and transporting the pulverized coal from a pulverized coal outlet to a pulverized coal combustion device ,
Supplying hot air into the coal pulverizer and drying the pulverized low-grade coal ;
Measuring CO concentration at the pulverized coal outlet to detect CO;
According to the detected CO concentration of CO, by reducing the flow rate of the hot air supplied to the inside of the coal pulverizer, the amount of heat of the hot air is reduced, and the amount of heat of the hot air that has been reduced is supplied. Performing a control to reduce the amount of the low-grade coal
Have,
A coal pulverizing method comprising supplying pulverized coal obtained by pulverizing high-grade coal to the pulverized coal combustion device in accordance with the reduced amount of the low-grade coal .

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