Coal mill deflagration fire extinguishing system and fire extinguishing method

Abstract

The invention discloses a coal mill deflagration fire extinguishing system and fire extinguishing method.The coal mill deflagration fire extinguishing system comprises a coal bunker, a coal feeding unit, a coal milling unit, a sealing air mother pipe and a fan set, coal slag in the coal bunker falls into the coal feeding unit, the coal feeding unit conveys the coal slag to the coal milling unit, and the fan set is arranged on one side of the coal milling unit; the fan set is in sealing connection with a sealing air mother pipe, the sealing air mother pipe is in sealing connection with the coal grinding unit, one end of the fire extinguishing pipeline is connected with a water source, and the other end of the fire extinguishing pipeline is arranged on the coal feeding unit. The coal mill has the beneficial effects that cooling water is introduced into the coal mill through the coal dropping pipe of the coal feeder on the coal feeder platform for cooling and fire extinguishing, but the existing coal mill lacks a cooling medium after detonation and cannot be cooled and extinguished in time, so that the coal mill after detonation cannot be put into use in time, and the load of a unit is influenced.

Description

Technical Field

[0001] The present invention relates to the field of thermal power generation safety, and in particular to a coal mill deflagration fire extinguishing system and a fire extinguishing method. Background Art

[0002] The consequences of coal mill explosions are multi-dimensional, chain-like, and long-term, with impacts far exceeding those of a single accident. Systematic measures such as explosion-proof design (such as inerting systems and CO monitoring), strict operating procedures, and emergency plan drills are needed to minimize risks. Power plants should establish a three-in-one safety system of "prevention-monitoring-emergency" to control the consequences of explosions in the bud.

[0003] The original pulverizing system is equipped with inerting steam drawn from the auxiliary steam header, with a temperature between 280 degrees Celsius and 300 degrees Celsius and a pressure between 0.7Mpa and 0.8Mpa, which is used for inerting during operation to prevent explosions. After the pulverizing system explodes, the coal mill automatically isolates the outlet plug door, and the opening pressure of the coal mill explosion-proof membrane is 22kpa. After the pulverizing explosion is isolated, there is no way to relieve pressure, and the pressure of the coal mill inerting steam is much higher than the action pressure of the coal mill explosion-proof membrane. Therefore, it is not applicable after the coal mill explosion is isolated. Now we lack cooling medium after the coal mill explosion, and cannot cool and extinguish the fire in time, resulting in the coal mill after the explosion unable to be put into operation in time, affecting the load of the unit. Summary of the Invention

[0004] Therefore, the technical problem to be solved by the present invention is that after the pulverizing explosion is isolated, the pressure of the pulverizer inerting steam is much higher than the operating pressure of the pulverizer explosion-proof membrane because there is no passage to release pressure, so it is not applicable after the pulverizer explosion is isolated.

[0005] The above technical problems are solved by the following technical solutions: The present invention proposes a coal mill explosion fire extinguishing system, which includes a coal bunker, a coal feeding unit, a coal grinding unit, a sealed air main pipe and a fan unit. The coal slag in the coal bunker falls into the coal feeding unit, and the coal feeding unit transfers the coal slag to the coal grinding unit. The fan unit is arranged on one side of the coal grinding unit. The fan unit is sealed and connected to the sealed air main pipe, and the sealed air main pipe is sealed and connected to the coal grinding unit.

[0006] It also includes a fire extinguishing pipeline, one end of which is connected to a water source, and the other end is arranged on the coal feeding unit.

[0007] In a preferred embodiment of the coal mill deflagration fire extinguishing system of the present invention: at least one of the coal bunker, coal feeding unit, coal grinding unit and sealed fan is provided, and the fire extinguishing pipeline corresponds to the coal bunker, coal feeding unit and coal grinding unit one by one.

[0008] In a preferred embodiment of the coal mill deflagration fire extinguishing system of the present invention, the coal feeding unit includes a coal conveyor belt and a coal feeder, and the coal feeder uniformly conveys coal to the coal conveyor belt according to a set flow rate.

[0009] In a preferred embodiment of the coal mill explosion fire extinguishing system of the present invention: the coal mill unit includes a coal dropping pipe and a coal mill, the coal dropping pipe is arranged between the coal feeder and the coal mill, and the coal slag falls into the coal mill from the coal conveyor belt outlet and is connected by the coal dropping pipe.

[0010] In a preferred embodiment of the coal mill deflagration fire extinguishing system of the present invention, the connection end between the fire extinguishing pipeline and the coal feeder is arranged on the side wall of the coal feeder outlet.

[0011] In a preferred embodiment of the coal mill deflagration fire extinguishing system of the present invention: a primary manual door, a filter screen, a solenoid valve and a secondary manual door are sequentially arranged on the fire extinguishing pipeline.

[0012] In a preferred embodiment of the coal mill deflagration fire extinguishing system of the present invention: the fan unit includes a burner large wind box and a sealed fan, and the burner large wind box is arranged on one side of the sealed fan;

[0013] The sealed air main pipe includes a hot primary air main pipe and a cold primary air main pipe, and the sealed fan outlet blows toward the hot primary air main pipe and the cold primary air main pipe respectively. The hot primary air main pipe and the cold primary air main pipe are connected to the coal mill.

[0014] In a preferred embodiment of the coal mill explosion fire extinguishing system of the present invention, the water source connected to the fire extinguishing pipeline is demineralized water.

[0015] The present invention also proposes a method for extinguishing coal mill explosion fire:

[0016] and:

[0017] a. The coal feeder's coal capacity is greater than 20t / h,

[0018] b. No other coal mills exploded,

[0019] c. Anti-explosion sub-ring is put into use,

[0020] d. "Unit RB" or "any primary wind turbine blade is manually cut" or "hot primary air main pipe pressure is greater than 11kPa or less than 6.6kPa", the anti-explosion sub-ring is triggered.

[0021] e. Or:

[0022] The coal feeder is running and the air-powder pressure at the mill outlet rises by 2 kPa within 30 seconds, triggering the "X mill outlet pressure sudden rise" ASD alarm. The shielded measuring point is inaccurate and the sudden rise and fall within 0.5 seconds is RR6. If it falls below 4.5 kPa, the reset is delayed for 1 minute;

[0023] If the set value of any point of the air-powder mixture temperature of the coal mill separator is greater than 7°C, the ASD alarm of "X coal mill separator air-powder temperature suddenly rises" will be triggered, and the measuring point will be shielded from sudden rise and fall of RR30 within 0.5s. The value will be restored to a value with a pairwise deviation of less than 5°C, and the inaccuracy will be reset after a delay of 1 minute.

[0024] Among the 4-way coal mill outlet air and powder temperatures, the highest value to the lowest value is greater than 7°C, triggering the "X coal mill outlet powder pipe temperature deviation is large" ASD alarm; the highest value to the lowest value is greater than 7°C and the coal feeder is running, triggering the deflagration sub-ring action, shielding the measuring point from inaccuracy for 0.5s sudden rise and fall RR30, and the value recovers to the highest value to the lowest value <7°C, delaying 1min to reset the inaccuracy,

[0025] Action result of explosion-proof sub-ring:

[0026] Ⅰ. Fully open the cold air regulating door of the coal mill. If the load during operation is less than 300MW, open the cold air regulating door to 75%;

[0027] II. The electric door for inerting steam of coal mill is opened and then paused after 10 seconds;

[0028] III. Shield the explosion sub-rings of other coal mills for 90 seconds.

[0029] The invention also proposes a preferred embodiment of a method for extinguishing coal mill explosion fire:

[0030] and:

[0031] a. The coal feeder's coal capacity is greater than 20t / h,

[0032] b. No other coal mills exploded,

[0033] c. Anti-explosion sub-ring is put into use,

[0034] d. "Primary fan RB" or "any primary fan blade cut manually" or "hot primary air main pipe pressure is greater than 11kPa or less than 6.6kPa", the anti-explosion sub-ring is triggered.

[0035] e. Select 3 of the following 4 conditions and maintain for 300 seconds if any one of them is met:

[0036] The coal feeder is running and the air and powder pressure at the grinding outlet rises by 2kPa within 30s;

[0037] The coal feeder is running and the air volume at the coal mill inlet drops by 5t / h within 30s;

[0038] When the air-powder mixture temperature of the coal mill separator meets the above three points and the set value is greater than 7°C, the trigger signal is "1" and maintained for 30 seconds;

[0039] When the maximum to minimum temperature of the air-powder temperature at the outlet of the 4-way coal mill is greater than 7°C and the coal feeder is running, the signal "1" is triggered and maintained for 30 seconds;

[0040] Action result of explosion-proof sub-ring:

[0041] Ⅰ. Fully open the cold air regulating door of the coal mill, the pulse signal is 30S. If the load is less than 300MW during operation, the cold air regulating door is opened to 75%, the pulse signal is 30S.

[0042] Ⅱ. The electric door of the coal mill inerting steam is opened for 10 seconds and then paused.

[0043] Ⅲ. Shield the other coal mill deflagration sub-rings from operating for 90 seconds.

[0044] IV. When the temperature of the coal mill air-powder separator reaches 90℃, the coal feeder will trip and the coal mill separator air-powder mixed temperature high trip protection will be locked for 900s.

[0045] V. If the A or C coal mill explosion-proof sub-ring is not in action, and the A or C coal feeder is in operation, the corresponding layer plasma is put into operation, and the pulse signal is 30S, the ASD alarm "the explosion-proof sub-ring is in action and the A or C layer plasma is put into operation" is triggered, and the ASD alarm "the explosion-proof sub-ring is in action and the X coal feeder is tripped" is triggered.

[0046] After the explosion-proof sub-ring trips the X coal feeder, and then the coal mill trips due to the high outlet temperature of the coal mill, the coal mill system is automatically isolated, and then the water injection fire extinguishing solenoid valve is opened in a chain, and the water fire extinguishing solenoid valve is automatically closed after 10L.

[0047] The beneficial effect of the present invention is that cooling water is introduced into the coal mill through the coal feeder coal drop pipe on the coal feeder platform for cooling and fire extinguishing. However, the coal mill currently lacks cooling medium after explosion and cannot be cooled and extinguished in time, resulting in the coal mill after explosion being unable to be put into operation in time, affecting the load of the unit. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings of the embodiments of the present invention. Obviously, the drawings described below only relate to some embodiments of the present invention and are not intended to limit the present invention. Among them:

[0049] Figure 1 Shows an overall display diagram of a coal mill deflagration fire extinguishing system;

[0050] Figure 2 A partial diagram of a coal mill deflagration fire extinguishing system is shown;

[0051] Figure 3 A partially enlarged view of a coal mill deflagration fire extinguishing system is shown. DETAILED DESCRIPTION

[0052] In order to enable those skilled in the art to better understand the present invention, the present invention is further described in detail below with reference to specific embodiments and the accompanying drawings.

[0053] The terms used in the present invention are those commonly used in the art in view of the functions of the present invention, but these terms may vary according to the intentions of those skilled in the art, precedents, or new technologies in the art. In addition, specific terms may be selected by the applicant, and in such cases, their detailed meanings will be described in the detailed description of the present invention. Therefore, the terms used in the specification should not be understood as simple names, but rather as the meanings of the terms and the overall description of the present invention.

[0054] Reference Figure 1 The present embodiment provides a coal mill explosion fire extinguishing system, including a coal bunker 1, a coal feeding unit 2, a coal grinding unit 3, a sealed air main pipe 4 and a fan group 5. The coal slag in the coal bunker 1 falls into the coal feeding unit 2, and the coal feeding unit 2 transfers the coal slag to the coal grinding unit 3. The fan group 5 is arranged on one side of the coal grinding unit 3. The fan group 5 is sealed and connected to the sealed air main pipe 4, and the sealed air main pipe 4 is sealed and connected to the coal grinding unit 3. In this embodiment, the top of the coal bunker 1 is exploded from a 22-meter conical bottom to the coal feeding unit 2. The height of the coal feeding unit 2 is 13.7m, the height of the coal grinding unit 3 is about 6m, the height of the sealed air main pipe 4 is about 6m, and the sealed air main pipe 4 is arranged parallel to the coal grinding unit 3. It also includes a fire extinguishing pipeline 6, one end of the fire extinguishing pipeline 6 is connected to a water source, and the other end is arranged at the coal feeding unit 2.

[0055] Reference Figure 1 As an optional embodiment, at least one of the coal bunker 1, coal feeding unit 2, coal grinding unit 3 and fan group 5 is provided, and the fire extinguishing pipeline 6 corresponds to the coal bunker 1, coal feeding unit 2 and coal grinding unit 3 one by one. In this embodiment, the number of coal bunkers 1, coal feeding units 2 and coal grinding units 3 is 6, and the coal bunker 1, coal feeding unit 2 and coal grinding unit 3 are arranged in parallel. There are two fan groups 5, which supply air for sealing and blowing the coal machine, coal grinding machine and coal powder pipe. The primary air system is equipped with two axial flow primary fans with adjustable blades, and a muffler is installed at the inlet. The outlet of the two primary fans respectively branches out one path to supply air to the cold primary air main pipe, and the other path is heated by the air preheater and then merged into the hot primary air main pipe.

[0056] Reference Figures 1 to 3 As an optional embodiment, the coal feeding unit 2 includes a coal conveying belt 21 and a coal feeder 22. The coal feeder 22 evenly conveys the coal to the coal conveying belt 21 according to a set flow rate.

[0057] Preferably, the coal grinding unit 3 includes a coal dropping pipe 31 and a coal mill 32. The coal dropping pipe 31 is arranged between the coal feeder 22 and the coal mill 32. The coal slag falls into the coal mill 32 from the outlet of the coal conveyor belt 21 and is connected by the coal dropping pipe 31. In this embodiment, the coal dropping pipe 31 is made entirely of stainless steel and is polished internally to ensure smooth coal flow. It complies with the requirements of the National Fire Protection Association NFPA8503 and can withstand an explosion pressure of 0.35 MPa.

[0058] Preferably, the connection end of the fire extinguishing pipe 6 and the coal feeder 22 is arranged on the side wall of the coal feeder 22 outlet. The fire extinguishing pipe 6 is arranged on the side wall of the coal feeder 22 outlet for the best effect. If the fire extinguishing pipe is connected to the side wall of the coal drop pipe, first, the fire extinguishing pipe is easily blocked by the coal flow and is difficult to clean. Second, if the pipe leaks, it is easy to cause coal to stick to the inner wall of the coal drop pipe. In this embodiment, the side wall of the coal feeder 22 outlet is set, because there are two peep windows before and after the coal feeder 22, which can be used to see the coal input and output of the coal feeder 22. There is a peep window obliquely above the top of the coal drop pipe 31 to see whether the coal drop pipe is blocked by sticky coal.

[0059] Preferably, a primary manual door 61, a filter 62, a solenoid valve 63 and a secondary manual door 64 are sequentially provided on the fire extinguishing pipeline 6. The primary manual door 61 is provided to facilitate isolation and maintenance when the secondary manual door 64 or the solenoid valve 63 leaks. The primary manual door 61 is a normally open door, the filter 62 is used to filter impurities, and the solenoid valve 63 is used to facilitate remote control and opening of the fire extinguishing operation. When the solenoid valve 63 fails, the secondary manual door 64 cooperates with the desalted water to extinguish the fire in the pulverizing system. The primary manual door 61, the primary manual door 61 and the secondary manual door 64 are isolated from the solenoid valve 63 before and after. A flow meter is installed behind the solenoid valve 63 to control the water volume by switching the solenoid valve 63. When a single explosion trips, the coal mill 32 automatically sprays 0.5 tons of water and automatically shuts down (the volume of the stone coal hopper slag box at the bottom of the coal mill 32 is 0.5m 3 There is a need to manually inject water through the electromagnetic valve 63 later, so that the water can completely enter the stone coal hopper and be emptied after the fire is extinguished.

[0060] Preferably, the fan group 5 includes a burner large wind box 51 and a sealed fan 52, and the burner large wind box 51 is arranged on one side of the sealed fan 52; the sealed air main pipe 4 includes a hot primary air main pipe 41 and a cold primary air main pipe 42, and the outlet of the sealed fan 52 blows to the hot primary air main pipe 41 and the cold primary air main pipe 42 respectively, and the hot primary air main pipe 41 and the cold primary air main pipe 42 are connected to the pulverizer 32. The boiler is equipped with two sealed fans 52. After the air is pressurized by the primary fan, it is divided into two paths at the outlet of the primary fan, one of which is the cold primary air; the other path goes to the air preheater first wind bin, and becomes hot primary air after being heated by the air preheater. The cold and hot primary air are mixed in a certain proportion at the inlet of the pulverizer 32 to control the primary air temperature entering the pulverizer 32. The primary air temperature entering the pulverizer 32 can be adjusted by the damper plates on the cold and hot primary air ducts.

[0061] Furthermore, the water source connected to the fire extinguishing pipeline 6 is desalted water. In this embodiment, the preferred water source is desalted water, which has cleaner water quality and is more suitable for actual use in the factory.

[0062] Reference Figures 1 to 3 , coal mill explosion fire extinguishing method,

[0063] and:

[0064] a. The coal capacity of coal feeder 22 is greater than 20t / h,

[0065] b. No other coal mill 32 explodes,

[0066] c. Anti-explosion sub-ring is put into use,

[0067] d. "Unit RB" or "any primary wind turbine blade is manually cut" or "hot primary air main pipe 41 pressure is greater than 11kPa or less than 6.6kPa", the anti-explosion sub-ring is triggered.

[0068] e. Or:

[0069] e1 Coal feeder 22 is running and the air-powder pressure at the mill outlet rises by 2 kPa within 30 seconds, triggering the "X Coal Mill 32 Outlet Pressure Sudden Rise" ASD alarm. The shielded measuring point is inaccurate and the sudden rise and fall within 0.5 seconds is RR6. If it falls below 4.5 kPa, the reset is delayed for 1 minute;

[0070] If the set value of the air-powder mixture temperature at any point of the 32 separator of the e2 coal mill is greater than 7°C, the ASD alarm of "sudden rise in air-powder temperature of 32 separator of the X coal mill" will be triggered, and the sudden rise and fall RR30 within 0.5s of the shielded measuring point will be inaccurate. The value will be restored to a value less than 5°C with a delay of 1 minute to reset the inaccuracy.

[0071] The temperature of the air powder at the outlet of the e34 coal mill 32 is greater than 7°C from the highest to the lowest value, triggering the ASD alarm of "large temperature deviation of the powder pipe at the outlet of the X coal mill 32"; the temperature of the air powder at the outlet of the e34 coal mill 32 is greater than 7°C and the coal feeder 22 is running, triggering the action of the deflagration sub-ring, shielding the measuring point from inaccuracy for 0.5s and sudden rise and fall RR30, and the value recovers to the highest to lowest value <7°C, with a delay of 1 minute to reset the inaccuracy.

[0072] Action result of explosion-proof sub-ring:

[0073] Ⅰ. Fully open the cold air regulating door of coal mill 32. If the load during operation is less than 300MW, open the cold air regulating door to 75%;

[0074] II. The electric door of the inerting steam of the coal mill 32 is opened for 10 seconds and then paused;

[0075] Ⅲ. Shield the other coal mill 32 deflagration sub-rings from moving for 90 seconds.

[0076] The above operations are based on the inerting steam being drawn from the auxiliary steam header.

[0077] Preferably,

[0078] and:

[0079] a. The coal capacity of coal feeder 22 is greater than 20t / h,

[0080] b. No other coal mill 32 explodes,

[0081] c. Anti-explosion sub-ring is put into use,

[0082] d. "Primary fan RB" or "any primary fan blade cut manually" or "hot primary air main pipe 41 pressure is greater than 11kPa or less than 6.6kPa", the anti-explosion sub-ring is triggered.

[0083] e. Select 3 of the following 4 conditions and maintain for 300 seconds if any one of them is met:

[0084] e1 Coal feeder 22 is running and the air and powder pressure at the grinding outlet rises by 2kPa within 30s;

[0085] e2 Coal feeder 22 is running and the air volume at the inlet of coal mill 32 drops by 5t / h within 30s;

[0086] The air-powder mixture temperature of the 32 separator of the e3 coal mill meets the above three points and the set value is greater than 7°C, triggering the signal "1" and maintaining it for 30 seconds;

[0087] When the air-powder temperature at the outlet of the 32nd coal mill on the e44 line is greater than 7°C from the highest to the lowest value and the coal feeder is running, the signal "1" is triggered and maintained for 30 seconds;

[0088] Action result of explosion-proof sub-ring:

[0089] Ⅰ. Fully open the cold air regulating door of coal mill 32, pulse signal 30S, if the load is less than 300MW during operation, the cold air regulating door is opened to 75%, pulse signal 30S,

[0090] Ⅱ. The electric door of inerting steam of coal mill 32 is open for 10 seconds and then paused.

[0091] Ⅲ. Shield the other coal mill 32 deflagration sub-rings from moving for 90 seconds.

[0092] IV. When the temperature of the air-powder separator of coal mill 32 reaches 90℃, the coal feeder 22 will be tripped and the high temperature trip protection of the air-powder mixture of the separator of coal mill 32 will be locked for 900s.

[0093] V. If the A or C coal mill 32 anti-explosion sub-ring is not in action, and the A or C coal feeder 22 is in operation, the corresponding layer plasma is put into operation, and the pulse signal is 30S, triggering the ASD alarm "anti-explosion sub-ring is in action and the A or C layer plasma is put into operation",

[0094] Trigger ASD alarm, "anti-explosion sub-ring trip X coal feeder 22",

[0095] After the explosion-proof sub-ring trips the X coal feeder 22, the high outlet temperature of the coal mill 32 triggers the tripping of the coal mill 32. The coal mill 32 system is automatically isolated, and then the interlocking water injection fire extinguishing solenoid valve 63 is added. After 10L, the water injection fire extinguishing solenoid valve 63 is automatically closed.

[0096] The above operation is to extinguish the fire pipeline 6, so that the coal dropping pipeline 31 is cooled and extinguished after the explosion occurs.

[0097] Finally, it should be pointed out that the methods and devices described in detail above are merely embodiments, and those skilled in the art can modify these embodiments in different ways without departing from the scope of the present invention.

Claims

1. A coal mill deflagration fire extinguishing system, characterized by: include, A coal bunker (1), a coal feeding unit (2), a coal grinding unit (3), a sealed air main pipe (4) and a fan unit (5); coal slag in the coal bunker (1) falls into the coal feeding unit (2); the coal feeding unit (2) transfers the coal slag to the coal grinding unit (3); the fan unit (5) is arranged on one side of the coal grinding unit (3); the fan unit (5) is sealed and connected to the sealed air main pipe (4); the sealed air main pipe (4) is sealed and connected to the coal grinding unit (3); It also includes a fire extinguishing pipeline (6), one end of which is connected to a water source, and the other end of which is arranged on the coal feeding unit (2).

2. The coal mill deflagration fire extinguishing system according to claim 1, characterized in that: At least one of the coal bunker (1), coal feeding unit (2), coal grinding unit (3) and fan unit (5) is provided, and the fire extinguishing pipeline (6) corresponds one to one with the coal bunker (1), coal feeding unit (2) and coal grinding unit (3).

3. The coal mill deflagration fire extinguishing system according to claim 1, characterized in that: The coal feeding unit (2) comprises a coal conveying belt (21) and a coal feeder (22); the coal feeder (22) evenly conveys coal to the coal conveying belt (21) according to a set flow rate.

4. The coal mill deflagration fire extinguishing system according to claim 3, characterized in that: The coal grinding unit (3) comprises a coal dropping pipe (31) and a coal mill (32). The coal dropping pipe (31) is arranged between the coal feeder (22) and the coal mill (32). Coal slag falls from the outlet of the coal conveyor belt (21) into the coal mill (32) and is connected by the coal dropping pipe (31).

5. The coal mill deflagration fire extinguishing system according to claim 4, characterized in that: The connection end between the fire extinguishing pipeline (6) and the coal feeder (22) is arranged on the outlet side wall of the coal feeder (22).

6. The coal mill deflagration fire extinguishing system according to claim 1, characterized in that: The fire extinguishing pipeline (6) is provided with a primary manual door (61), a filter (62), a solenoid valve (63) and a secondary manual door (64) in sequence.

7. The coal mill deflagration fire extinguishing system according to claim 1, characterized in that: The fan unit (5) includes a burner large wind box (51) and a sealed fan (52), wherein the burner large wind box (51) is arranged on one side of the sealed fan (52); The sealed air main pipe (4) comprises a hot primary air main pipe (41) and a cold primary air main pipe (42); the outlet of the sealed fan (52) blows toward the hot primary air main pipe (41) and the cold primary air main pipe (42), respectively; the hot primary air main pipe (41) and the cold primary air main pipe (42) are connected to the coal mill (32).

8. The coal mill deflagration fire extinguishing system according to claim 1, characterized in that: The fire extinguishing pipeline (6) is connected to a water source which is desalted water.

9. A method for extinguishing a coal mill deflagration fire, characterized by: Based on the coal mill deflagration fire extinguishing system according to any one of claims 1 to 8, the method comprises: and: a. Coal feeder (22) with a coal capacity greater than 20t / h, b. No other coal mill (32) deflagration, c. Anti-explosion sub-ring is put into use, d. "Unit RB" or "any primary wind turbine blade cut manually" or "hot primary air main pipe (41) pressure is greater than 11kPa or less than 6.6kPa", the anti-explosion sub-ring is triggered, e. Or: (e1) The coal feeder (22) is running and the air-powder pressure at the mill outlet rises by 2 kPa within 30 seconds, triggering the "X mill (32) outlet pressure sudden rise" ASD alarm, shielding the measuring point from inaccuracy, sudden rise and fall within 0.5 seconds RR6, and reset the inaccuracy after a delay of 1 minute below 4.5 kPa; (e2) The set value of the air-powder mixture temperature of the coal mill (32) separator is greater than 7°C at any point, and the "X coal mill (32) separator air-powder temperature suddenly rises" ASD alarm is triggered, shielding the measuring point from inaccuracy by RR30 within 0.5s, and the value is restored to a value with a pairwise deviation of less than 5°C, and the inaccuracy is reset after a delay of 1min; (e3) The maximum to minimum value of the air-powder temperature at the outlet of the 4-way coal mill (32) is greater than 7°C, triggering the ASD alarm of "large deviation of temperature of the powder pipe at the outlet of the X coal mill (32)"; the maximum to minimum value is greater than 7°C and the coal feeder (22) is running, triggering the action of the deflagration sub-ring, shielding the measurement point from inaccuracy for 0.5s, sudden rise and fall RR30, and the value is restored to the maximum to minimum value <7°C, with a delay of 1min to reset the inaccuracy. Action result of explosion-proof sub-ring: Ⅰ. Fully open the cold air regulating door of the coal mill (32). If the load during operation is less than 300MW, open the cold air regulating door to 75%; II. The inerting steam electric door of the coal mill (32) is opened for 10 seconds and then paused; III. Shield the explosion sub-rings of other coal mills (32) for 90 seconds.

10. A method for extinguishing a coal mill deflagration fire, characterized by: and: a. Coal feeder (22) with a coal capacity greater than 20t / h, b. No other coal mill (32) deflagration, c. Anti-explosion sub-ring is put into use, d. "Primary fan RB" or "Any primary fan blade cut manually" or "The pressure of the hot primary air main pipe (41) is greater than 11kPa or less than 6.6kPa", the anti-explosion sub-ring is triggered, e. Select 3 of the following 4 conditions and maintain for 300 seconds if any one of them is met: (e1) The coal feeder (22) is running and the air-powder pressure at the grinding outlet rises by 2 kPa within 30 seconds; (e2) The coal feeder (22) is running and the air volume at the inlet of the coal mill (32) drops suddenly by 5 t / h within 30 seconds; (e3) The air-powder mixture temperature of the coal mill (32) separator satisfies the above three points and the set value is greater than 7°C, triggering signal "1" and maintaining it for 30 seconds; (e4) When the maximum to minimum values ​​of the air-powder temperature at the outlet of the 4-way coal mill (32) are greater than 7°C and the coal feeder is running, the trigger signal "1" is maintained for 30 seconds; Action result of explosion-proof sub-ring: Ⅰ. Fully open the cold air regulating door of the coal mill (32), pulse signal 30S, if the load is less than 300MW during operation, the cold air regulating door is opened to 75%, pulse signal 30S, Ⅱ. The inerting steam electric door of the coal mill (32) is opened for 10 seconds and then paused. Ⅲ. Shield the other coal mill (32) deflagration sub-rings for 90 seconds. IV. When the temperature of the air-powder separator of the coal mill (32) reaches 90°C, the coal feeder (22) is tripped and the high temperature trip protection of the air-powder mixture of the coal mill (32) separator is locked for 900s. V. If the anti-explosion sub-ring of the A or C coal mill (32) is not in operation, and the A or C coal feeder (22) is in operation, the corresponding layer plasma is put into operation, and the pulse signal is 30S, triggering the ASD alarm "anti-explosion sub-ring is in operation and the A or C layer plasma is put into operation", Trigger ASD alarm, "Anti-explosion sub-ring trips X coal feeder (22)", After the explosion-proof sub-ring trips the X coal feeder (22), the high outlet temperature of the coal mill (32) triggers the tripping of the coal mill (32), and the coal mill (32) system is automatically isolated. Then, the interlocking water injection fire extinguishing solenoid valve (63) is added, and the water injection fire extinguishing solenoid valve (63) is automatically closed after 10L.

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