CN111256107A - Explosion-proof system for grinding high-volatile coal by double-inlet and double-outlet coal mill and working method - Google Patents

Explosion-proof system for grinding high-volatile coal by double-inlet and double-outlet coal mill and working method Download PDF

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Publication number
CN111256107A
CN111256107A CN202010247008.3A CN202010247008A CN111256107A CN 111256107 A CN111256107 A CN 111256107A CN 202010247008 A CN202010247008 A CN 202010247008A CN 111256107 A CN111256107 A CN 111256107A
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China
Prior art keywords
double
coal
inlet
outlet
mill
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Pending
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CN202010247008.3A
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Chinese (zh)
Inventor
冯树臣
李泓
杨希刚
李永生
周振华
张金祥
陈国庆
何陆灿
戴维葆
姜晓弢
蔡培
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Southeast University
GD Power Dalian Zhuanghe Power Generation Co Ltd
Guodian Nanjing Electric Power Test Research Co Ltd
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Southeast University
GD Power Dalian Zhuanghe Power Generation Co Ltd
Guodian Nanjing Electric Power Test Research Co Ltd
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Priority to CN202010247008.3A priority Critical patent/CN111256107A/en
Publication of CN111256107A publication Critical patent/CN111256107A/en
Pending legal-status Critical Current

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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23B—METHODS OR APPARATUS FOR COMBUSTION USING ONLY SOLID FUEL
    • F23B40/00—Combustion apparatus with driven means for feeding fuel into the combustion chamber
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F22—STEAM GENERATION
    • F22D—PREHEATING, OR ACCUMULATING PREHEATED, FEED-WATER FOR STEAM GENERATION; FEED-WATER SUPPLY FOR STEAM GENERATION; CONTROLLING WATER LEVEL FOR STEAM GENERATION; AUXILIARY DEVICES FOR PROMOTING WATER CIRCULATION WITHIN STEAM BOILERS
    • F22D1/00—Feed-water heaters, i.e. economisers or like preheaters
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23K—FEEDING FUEL TO COMBUSTION APPARATUS
    • F23K1/00—Preparation of lump or pulverulent fuel in readiness for delivery to combustion apparatus
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23K—FEEDING FUEL TO COMBUSTION APPARATUS
    • F23K3/00—Feeding or distributing of lump or pulverulent fuel to combustion apparatus
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23L—SUPPLYING AIR OR NON-COMBUSTIBLE LIQUIDS OR GASES TO COMBUSTION APPARATUS IN GENERAL ; VALVES OR DAMPERS SPECIALLY ADAPTED FOR CONTROLLING AIR SUPPLY OR DRAUGHT IN COMBUSTION APPARATUS; INDUCING DRAUGHT IN COMBUSTION APPARATUS; TOPS FOR CHIMNEYS OR VENTILATING SHAFTS; TERMINALS FOR FLUES
    • F23L13/00—Construction of valves or dampers for controlling air supply or draught
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23L—SUPPLYING AIR OR NON-COMBUSTIBLE LIQUIDS OR GASES TO COMBUSTION APPARATUS IN GENERAL ; VALVES OR DAMPERS SPECIALLY ADAPTED FOR CONTROLLING AIR SUPPLY OR DRAUGHT IN COMBUSTION APPARATUS; INDUCING DRAUGHT IN COMBUSTION APPARATUS; TOPS FOR CHIMNEYS OR VENTILATING SHAFTS; TERMINALS FOR FLUES
    • F23L15/00—Heating of air supplied for combustion
    • F23L15/02—Arrangements of regenerators
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01D—MEASURING NOT SPECIALLY ADAPTED FOR A SPECIFIC VARIABLE; ARRANGEMENTS FOR MEASURING TWO OR MORE VARIABLES NOT COVERED IN A SINGLE OTHER SUBCLASS; TARIFF METERING APPARATUS; MEASURING OR TESTING NOT OTHERWISE PROVIDED FOR
    • G01D21/00—Measuring or testing not otherwise provided for
    • G01D21/02—Measuring two or more variables by means not covered by a single other subclass
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E20/00—Combustion technologies with mitigation potential
    • Y02E20/34—Indirect CO2mitigation, i.e. by acting on non CO2directly related matters of the process, e.g. pre-heating or heat recovery

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Physics & Mathematics (AREA)
  • Thermal Sciences (AREA)
  • General Physics & Mathematics (AREA)
  • Disintegrating Or Milling (AREA)
  • Crushing And Grinding (AREA)

Abstract

The invention relates to an explosion-proof system for grinding high volatile coal by a double-inlet and double-outlet coal mill and a working method, and the explosion-proof system comprises a raw coal hopper, a coal feeder, the double-inlet and double-outlet coal mill, a pulverized coal separator, a burner, a boiler, an air preheater, a dust remover, an induced draft fan and a chimney, wherein the raw coal hopper is connected with the coal feeder, the coal feeder is connected with an inlet of the double-inlet and double-outlet coal mill, an outlet of the double-inlet and double-outlet coal mill is connected with the pulverized coal separator, the pulverized coal separator is connected with the burner, the burner is connected with an inlet of the boiler, the air preheater is arranged at an outlet of the boiler and is connected with the dust remover, the dust remover is connected with an; the system further comprises a cold smoke pipeline and a cold smoke fan, one end of the cold smoke pipeline is connected with an outlet of the draught fan, the other end of the cold smoke pipeline is connected with an inlet of the cold smoke fan, and an outlet of the cold smoke fan is connected with an inlet of the double-inlet and double-outlet coal mill. The system and the method can fundamentally solve the problem that deflagration is easy to occur when the high-volatile coal is milled by the double-inlet and double-outlet coal mill and is stopped.

Description

Explosion-proof system for grinding high-volatile coal by double-inlet and double-outlet coal mill and working method
Technical Field
The invention relates to an explosion-proof system for grinding high volatile coal seeds by a double-inlet and double-outlet coal mill and a working method, belonging to the technical field of explosion prevention of coal mills of large coal-fired power plants.
Background
The high-volatile coal for combustion can effectively improve the combustion stability of the boiler, reduce the unburned carbon loss of dry ash, improve the thermal efficiency of the boiler and reduce the emission concentration of nitrogen oxide at the outlet of the economizer; in recent years, various coal-fired power plants increase the purchase of high-volatile coal types such as domestic bituminous coal, Indonesian bituminous coal and Indonesian lignite; finally, the volatile content of the coal entering the furnace of the power plant is higher than that of the designed coal, so that great potential safety hazard is brought to a coal pulverizing system of the steel ball coal mill. The double-inlet and double-outlet coal mill is one of the steel ball coal mills, and is widely applied to a coal pulverizing system of a coal-fired power plant due to the advantages of high continuous operation rate, high storage capacity, quick response, high operation flexibility, lower air-coal ratio, capability of grinding various coal types with strong hardness and abrasiveness and the like. However, one of the biggest defects of the double-inlet and double-outlet coal mill is that the double-inlet and double-outlet coal mill is not suitable for milling high-volatile bituminous coal and lignite, and particularly, a certain amount of powder exists in the coal mill during the shutdown process of the coal mill, the stored powder between steel balls in the coal mill is difficult to be completely extracted out due to less cold air volume in the powder extraction process, the stored powder is repeatedly ground in the coal mill, the pulverized coal particles are finer and finer, and are in a continuous disturbance state, and the deflagration risk of the coal mill is higher.
Aiming at the characteristics of the double-inlet and double-outlet coal mill, the prevention of deflagration of a coal pulverizing system is a main work of safe operation of the double-inlet and double-outlet coal mill, and particularly, the prevention of deflagration of the coal mill in the process of stopping grinding is a difficult problem to be solved. In order to solve the above problems, the following methods are mainly used.
The part which is easy to accumulate powder is treated and an explosion vent is additionally arranged. The method is characterized in that positions, such as a capacity air box, a separator folding baffle, a separator manhole door dead angle, a separator powder return pipe, a central cylinder inner wall, a coal dropping pipe and the like, which are easy to accumulate powder are managed, meanwhile, an explosion door is additionally arranged to reduce the damage to equipment during deflagration, but the problem of deflagration of the double-inlet and double-outlet coal mill cannot be solved because powder is accumulated among steel balls in a cylinder of the coal mill during the process of stopping milling.
And a CO detection system is additionally arranged. The method is to use a CO concentration meter to diagnose in advance and take measures in advance. However, the detonation is a transient matter, and the detonation may occur without timely reaction of the CO concentration meter, so that the method cannot fundamentally solve the problem of the detonation of the double-inlet and double-outlet coal mill.
And introducing inert gas when the grinding is stopped. The method is used for reducing the oxygen content in the coal mill so as to achieve the purpose of explosion prevention. A commonly used inert gas is N2And CO2The method can prevent the explosion accident of the coal mill. However, the method needs to increase an inert gas storage tank and an inert gas decompression evaporation device, occupies a large area, needs to purchase a large amount of inert gas, and has high investment cost.
When the milling is stopped, the inerting steam is used. The method is the most common method, and the inert steam is used for not only reducing the oxygen content in the coal mill, but also improving the moisture in the coal mill and preventing the explosion of the coal mill. The inerting steam adopted by the existing coal mill is from superheated steam from an auxiliary header, the pressure and the temperature of a steam source of the steam system are not matched with the inerting steam pressure and the temperature required by the coal mill, and the steam needs to be subjected to temperature and pressure reduction treatment before being put into operation; inerting steam can improve moisture in the coal mill, is favorable to preventing the coal mill from deflagrating and taking place, but moisture also can be to the coal mill equipment having damaged, probably because the buggy meets water and causes inerting steam pipe to block up or the coal mill export powder pipe blocking phenomenon to take place, based on various unfavorable reasons, some power plants do not throw when the coal mill is shut down and move inerting steam to can't realize the explosion-proof function of coal mill.
Disclosure of Invention
The invention aims to solve the problems in the prior art and provides an explosion-proof system and an explosion-proof working method for effectively solving the deflagration problem when a double-inlet double-outlet coal mill is used for milling high-volatile coal and stops milling.
In order to achieve the purpose, the technical scheme provided by the invention is as follows: a high volatile coal explosion-proof system ground by a double-inlet and double-outlet coal mill comprises a raw coal hopper, a coal feeder, a double-inlet and double-outlet coal mill, a pulverized coal separator, a burner, a boiler, an air preheater, a dust remover, an induced draft fan and a chimney, wherein the raw coal hopper is connected with the coal feeder, the coal feeder is connected with an inlet of the double-inlet and double-outlet coal mill, an outlet of the double-inlet and double-outlet coal mill is connected with the pulverized coal separator, the pulverized coal separator is connected with the burner, the burner is connected with an inlet of the boiler, the air preheater is arranged at an outlet of the boiler and is connected with the dust remover, the dust remover is connected with an inlet of the induced draft fan, and an outlet of the induced draft; the system further comprises a cold smoke pipeline and a cold smoke fan, one end of the cold smoke pipeline is connected with an outlet of the draught fan, the other end of the cold smoke pipeline is connected with an inlet of the cold smoke fan, and an outlet of the cold smoke fan is connected with an inlet of the double-inlet and double-outlet coal mill.
The technical scheme is further designed as follows: a cold smoke fan front valve is arranged at a position, close to the cold smoke fan, of the cold smoke pipeline, and a cold smoke grinding inlet valve is arranged between the cold smoke fan and the double-inlet and double-outlet coal mill inlet.
An explosion-proof door is arranged between the cold grinding flue gas inlet valve and the inlet of the double-inlet and double-outlet coal mill.
And a hot primary air pipeline is connected to the pipeline between the mill cold flue gas inlet valve and the explosion-proof door, and a hot primary air door is arranged on the hot primary air pipeline.
And a cold primary air pipeline is also connected to the pipeline between the mill cold flue gas inlet valve and the explosion-proof door, and a cold primary air door is arranged on the cold primary air pipeline.
And a draught fan outlet flue gas temperature measuring instrument is arranged at the outlet of the draught fan.
And a mill inlet mixed air temperature measuring instrument is arranged at the inlet of the explosion door.
A pulverized coal pipe anemometer is arranged at an outlet of the pulverized coal separator; an oxygen meter is arranged in the double-inlet and double-outlet coal mill.
And a capacity air pipeline and a bypass air pipeline which are connected in parallel are arranged between the explosion door and the inlet of the double-inlet and double-outlet coal mill, and a capacity air door and a bypass air door are respectively arranged on the capacity air pipeline and the bypass air pipeline.
A working method of an explosion-proof system for grinding high volatile coal seeds by a double-inlet and double-outlet coal mill comprises the following steps:
when the double-inlet and double-outlet coal mill is ready to be shut down, gradually opening a cold primary air door, closing a hot primary air door, and when the temperature measured by a mixed air temperature measuring instrument at the inlet of the mill is equal to the temperature measured by a flue gas temperature measuring instrument at the outlet of an induced draft fan, opening a front valve of a cold flue gas blower and a valve at the inlet of the cold flue gas mill; meanwhile, the cold smoke blower is started, and smoke at the outlet of the draught fan is sent into a double-inlet and double-outlet coal mill after being boosted;
step two, setting the closing rate of the hot primary air door, gradually closing the hot primary air door until the hot primary air door is completely closed according to the set value, and adjusting the output of the cold smoke fan according to the speed measured by the mill tube anemometer in the closing process of the hot primary air door until the measured speed of the mill tube anemometer is kept unchanged;
step three, after the hot primary air door is completely closed, regulating the output of a cold smoke fan according to the speed measured by the mill tube air speed meter and the oxygen content of the coal mill system measured by the oxygen meter, and finally ensuring that the mill tube air speed and the internal oxygen content of the coal mill meet the requirements;
and step four, gradually reducing the output of the coal feeder until the output of the coal feeder is the lowest, then stopping the coal feeder, performing powder extraction on the coal mill, closing the capacity air and the bypass air of the coal mill after the powder extraction is finished, and then stopping the coal mill.
Compared with the prior art, the invention has the following beneficial effects:
compared with the method for treating the part easy to accumulate the powder, additionally arranging an explosion door and additionally arranging a CO detection system for pre-diagnosis in the prior art, the invention provides the explosion-proof system for grinding high-volatile coal by the double-inlet and double-outlet coal mill and the working method thereof, which can fundamentally solve the problem that the explosion is easy to occur when the grinding of the high-volatile coal by the double-inlet and double-outlet coal mill is stopped.
The system of the invention is different from the system for introducing the inert gas, does not need to purchase the inert gas, and has small occupied area and low cost; compared with the operation of inerting steam, the added cold flue gas does not contain a large amount of moisture, and the risk of blocking a powder pipe and the like can be avoided.
The explosion-proof system that this patent provided can increase the coal pulverizer air volume, reduces the internal coal dust volume of coal pulverizer barrel, reaches the purpose that prevents the coal pulverizer deflagration, compares total smoke gas volume simultaneously, and the cold flue gas volume of drawing forth is little, gets into furnace after through the coal pulverizer and almost has no influence to boiler thermal efficiency, because the flue gas oxygen volume that gets into furnace through the coal pulverizer is low, can effectively reduce economizer export nitrogen oxide's emission concentration.
Drawings
FIG. 1 is a schematic structural diagram of an explosion-proof system for grinding high-volatile coal by using a double-inlet and double-outlet coal mill of the invention;
FIG. 2 is a schematic diagram of the cold flue gas pipeline of the explosion-proof system of the invention connected with three coal mills.
In the figure: 1. a raw coal hopper; 2. a coal feeder; 3. a double-inlet and double-outlet coal mill; 4. a pulverized coal separator; 5. a burner; 6. a boiler; 7. an air preheater; 8. a dust remover; 9. an induced draft fan; 10. a chimney; 11. a cold flue gas pipeline; 12. a front valve of the smoke cooling fan; 13. a smoke cooling fan; 14. grinding a cold flue gas inlet valve; 15. a hot primary air damper; 16. a cold primary air door; 17. an explosion vent; 18. a volumetric air door; 19. a bypass air door; 20. a flue gas temperature measuring instrument at the outlet of the induced draft fan; 21. a mill inlet mixed air temperature measuring instrument; 22. a pulverized coal pipe anemometer; 23. an oxygen meter; 24. a computer;
3A, a coal mill A; 3B, a coal mill B; 3C, a coal mill C; 14A, a cold flue gas inlet valve of a coal mill A; 14B, a cold flue gas inlet valve of a coal mill B; 14C, a cold flue gas inlet valve of the coal mill C.
Detailed Description
The invention is described in detail below with reference to the figures and the specific embodiments.
Examples
As shown in fig. 1, the explosion-proof system for high volatile coal ground by the double-inlet and double-outlet coal mill of this embodiment includes raw coal hopper 1, coal feeder 2, double-inlet and double-outlet coal mill 3, coal dust separator 4, combustor 5, boiler 6, air preheater 7, dust remover 8, draught fan 9 and chimney 10, raw coal hopper 1 is connected with coal feeder 2, and coal feeder 2 is connected with double-inlet and double-outlet coal mill 3 entry linkage through estimating the pipeline, and double-inlet and double-outlet coal mill 3 export is connected with coal dust separator 4, coal dust separator 4 export is connected with combustor 5, combustor 5 and boiler 6 entry linkage, air preheater 7 sets up in boiler 6 export, and is connected with dust remover 8, dust remover 8 and draught fan 9 entry linkage, and draught fan 9 export is connected with chimney 10. In the embodiment, two inlets of the double-inlet and double-outlet coal mill 3 are both connected with a coal feeder 2, and two outlets are both connected with a coal dust separator 4.
The high-volatile coal explosion-proof system for grinding of the double-inlet and double-outlet coal mill comprises a cold flue gas flow regulating system and an automatic control system.
The cold flue gas flow regulating system comprises a cold flue gas pipeline 11 and a cold flue gas fan 13. And one end of the cold smoke pipeline 11 is connected with an outlet of the draught fan 9, the other end of the cold smoke pipeline is connected with an inlet of the cold smoke fan 13, and an outlet of the cold smoke fan 13 is connected with an inlet of the double-inlet double-outlet coal mill 3.
In this embodiment, a front valve 12 of the cold smoke blower is arranged at a position, close to the cold smoke blower 13, of the cold smoke pipeline 11, a cold smoke grinding inlet valve 14 is arranged between the cold smoke blower 13 and the inlet of the double-inlet and double-outlet coal mill 3, and an explosion door 17 is further arranged between the cold smoke grinding inlet valve 14 and the inlet of the double-inlet and double-outlet coal mill 3.
The cold flue gas pipeline 11 is led out from the outlet of the draught fan 9, and the cold flue gas is pumped out by the cold flue gas draught fan 13 to be boosted and finally enters the double-inlet and double-outlet coal mill 3. The output of the cold smoke blower 13 is adjustable, and the flow of cold smoke entering the coal mill can be adjusted. The cold flue gas pipeline 11 is provided with a cold flue gas blower front valve 12 and a mill cold flue gas inlet valve 14, and both the valves are open and fully-closed valves with non-adjustable flow. The explosion-proof door 17 arranged in the system further ensures the safety of the equipment. After the cold flue gas is taken to the draught fan 9, the flue gas contains less dust and the temperature of the flue gas is lower, so the cold flue gas draught fan 13 has good working environment and high stability.
The automatic control system comprises a primary hot air door 15, a draught fan outlet flue gas temperature measuring instrument 20, a mill inlet mixed air temperature measuring instrument 21, a milling pipe air velocity meter 22, an oxygen meter 23 and a computer 24. The hot primary air door 15, the draught fan outlet flue gas temperature measuring instrument 20, the mill inlet mixed air temperature measuring instrument 21, the grinding pipe air velocity meter 22, the oxygen meter 23 and the cold flue gas fan 13 are all connected with the computer 24, and finally the cold flue gas flow entering the coal mill is met and can be automatically controlled, so that the workload of operators is reduced.
And a hot primary air pipeline is connected to the pipeline between the mill cold flue gas inlet valve 14 and the explosion-proof door 17, and a hot primary air door 15 is arranged on the hot primary air pipeline. And a cold primary air pipeline is also connected to the pipeline between the mill cold flue gas inlet valve 14 and the explosion-proof door 17, and a cold primary air door 16 is arranged on the cold primary air pipeline.
And an outlet of the induced draft fan 9 is provided with an induced draft fan outlet flue gas temperature measuring instrument 20. And a mill inlet mixed air temperature measuring instrument 21 is arranged at the inlet of the explosion-proof door 17. A pulverized coal pipe anemometer 22 is arranged at the outlet of the pulverized coal separator 4; an oxygen meter 23 is arranged in the double-inlet and double-outlet coal mill 3.
And a capacity air pipeline and a bypass air pipeline which are connected in parallel are further arranged between the explosion door 17 and the inlet of the double-inlet and double-outlet coal mill 3, and a capacity air door 18 and a bypass air door 19 are respectively arranged on the capacity air pipeline and the bypass air pipeline. The double-inlet and double-outlet coal mill is provided with two symmetrical grinding loops, one is bypass air, and the action of the bypass air is that on one hand, the coal is mixed with raw coal in a mixing box for pre-drying, and on the other hand, the coal powder pipeline is kept to have enough wind speed for conveying coal powder; one path is volumetric wind; the volumetric air enters the cylinder body of the mill through the hot air pipe and the central pipe, the pulverized coal in the cylinder body is conveyed and dried, and the air-powder mixture is taken out of the mill through the annular pipeline between the central pipe and the hollow pipe.
The object of this embodiment is 3 BBD4060B type double-in double-out steel ball coal mills that a 330MW subcritical four corners tangential firing boiler was equipped with, and design coal kind dry ashless base volatile matter is 35%, and the dry ashless base volatile matter of actual burning coal kind is about 40%, and the coal mill often takes place the detonation phenomenon in the shut-down process, and is great to the equipment damage. The present embodiment will now be described in detail with reference to fig. 1 and 2. Raw coal in a raw coal hopper 1 enters a double-inlet double-outlet coal mill 3 through a coal feeder 2 to be ground, ground coal powder passes through a coal powder separator 4 and then enters a hearth 6 through a combustor 5 to be combusted, and flue gas in the hearth passes through an air preheater 7, a dust remover 8 and a draught fan 9 and is finally discharged to a chimney 10.
The coal mill of the embodiment is shut down as follows:
step 1: when the double-inlet and double-outlet coal mill 3 is ready to be shut down, the cold primary air door 16 of the coal mill is gradually opened, the hot primary air door 15 is closed, when the temperature measured by the mixed air temperature measuring instrument 21 at the mill inlet is equal to the temperature measured by the flue gas temperature measuring instrument 20 at the outlet of the draught fan, the computer 24 controls the front valve 12 of the cold flue gas blower and the inlet valve 14 of the cold flue gas blower to be automatically opened, meanwhile, the cold flue gas blower 13 is automatically started, and the flue gas at the outlet of the draught fan 9 is sent into the double-inlet and double-outlet coal mill 3 after being boosted.
Step 2: and setting a closing rate of 10% of the hot primary air door 15 closed every minute, closing the hot primary air door 15 by the computer 24 according to the set value until the hot primary air door 15 is completely closed, and in the closing process of the hot primary air door 15, adjusting the output of the cold smoke fan 13 by the computer 24 according to the speed measured by the pulverized coal pipe anemometer 22, and finally keeping the speed measured by the pulverized coal pipe anemometer 22 unchanged. The process cold primary damper 16 remains unchanged.
And step 3: after the hot primary air door 15 is completely closed, the computer 24 adjusts the output of the cold smoke blower 13 according to the speed measured by the coal mill powder pipe anemometer 22 and the oxygen content of the coal mill system measured by the oxygen meter 23, so as to ensure that the speed measured by the coal mill powder pipe anemometer 22 is greater than 18m/s (required by the operation regulation) and the internal oxygen content of the coal mill measured by the oxygen meter 23 is less than 16% (required by the explosion-proof regulation of the coal powder preparation and pulverization system). And gradually reducing the output force of the coal feeder 2 until the output force is lowest, closing an inlet inserting plate door of the coal feeder, stopping the coal feeder, performing powder extraction on the coal mill, slowly closing the capacity air 21 and the bypass air 22 of the coal mill after the powder extraction is finished, and stopping the coal mill.
The technical solutions of the present invention are not limited to the above embodiments, and all technical solutions obtained by using equivalent substitution modes fall within the scope of the present invention.

Claims (10)

1. A high volatile coal explosion-proof system ground by a double-inlet and double-outlet coal mill comprises a raw coal hopper, a coal feeder, a double-inlet and double-outlet coal mill, a pulverized coal separator, a burner, a boiler, an air preheater, a dust remover, an induced draft fan and a chimney, wherein the raw coal hopper is connected with the coal feeder, the coal feeder is connected with an inlet of the double-inlet and double-outlet coal mill, an outlet of the double-inlet and double-outlet coal mill is connected with the pulverized coal separator, the pulverized coal separator is connected with the burner, the burner is connected with an inlet of the boiler, the air preheater is arranged at an outlet of the boiler and is connected with the dust remover, the dust remover is connected with an inlet of the induced draft fan, and an outlet of the induced draft; the method is characterized in that: still include cold flue gas pipeline and cold flue gas fan, cold flue gas pipeline one end and draught fan exit linkage, the other end and cold flue gas fan entry linkage, cold flue gas fan export and the double entry double exit coal pulverizer entry linkage.
2. The explosion-proof system for grinding high volatile coal seeds by using the double-inlet and double-outlet coal mill as claimed in claim 1, wherein: a cold smoke fan front valve is arranged at a position, close to the cold smoke fan, of the cold smoke pipeline, and a cold smoke grinding inlet valve is arranged between the cold smoke fan and the double-inlet and double-outlet coal mill inlet.
3. The explosion-proof system for grinding high-volatile coal by using the double-inlet and double-outlet coal mill as claimed in claim 2, wherein: an explosion-proof door is arranged between the cold grinding flue gas inlet valve and the inlet of the double-inlet and double-outlet coal mill.
4. The explosion-proof system for grinding high-volatile coal by using the double-inlet and double-outlet coal mill as claimed in claim 3, wherein: and a hot primary air pipeline is connected to the pipeline between the mill cold flue gas inlet valve and the explosion-proof door, and a hot primary air door is arranged on the hot primary air pipeline.
5. The explosion-proof system for grinding high volatile coal by using the double-inlet and double-outlet coal mill as claimed in claim 4, wherein: and a cold primary air pipeline is also connected to the pipeline between the mill cold flue gas inlet valve and the explosion-proof door, and a cold primary air door is arranged on the cold primary air pipeline.
6. The explosion-proof system for grinding high volatile coal seeds by using the double-inlet and double-outlet coal mill as claimed in claim 5, wherein: and a draught fan outlet flue gas temperature measuring instrument is arranged at the outlet of the draught fan.
7. The explosion-proof system for grinding high volatile coal by using the double-inlet and double-outlet coal mill as claimed in claim 6, wherein: and a mill inlet mixed air temperature measuring instrument is arranged at the inlet of the explosion door.
8. The explosion-proof system for grinding high-volatile coal by using the double-inlet and double-outlet coal mill as claimed in claim 7, wherein: a pulverized coal pipe anemometer is arranged at an outlet of the pulverized coal separator; an oxygen meter is arranged in the double-inlet and double-outlet coal mill.
9. The explosion-proof system for grinding high volatile coal by using the double-inlet and double-outlet coal mill as claimed in claim 8, wherein: and a capacity air pipeline and a bypass air pipeline which are connected in parallel are arranged between the explosion door and the inlet of the double-inlet and double-outlet coal mill, and a capacity air door and a bypass air door are respectively arranged on the capacity air pipeline and the bypass air pipeline.
10. The operating method of the explosion-proof system for grinding high volatile coal by the double-inlet and double-outlet coal mill as claimed in claim 9, is characterized by comprising the following steps:
when the double-inlet and double-outlet coal mill is ready to be shut down, gradually opening a cold primary air door, closing a hot primary air door, and when the temperature measured by a mixed air temperature measuring instrument at the inlet of the mill is equal to the temperature measured by a flue gas temperature measuring instrument at the outlet of an induced draft fan, opening a front valve of a cold flue gas blower and a valve at the inlet of the cold flue gas mill; meanwhile, the cold smoke blower is started, and smoke at the outlet of the draught fan is sent into a double-inlet and double-outlet coal mill after being boosted;
step two, setting the closing rate of the hot primary air door, gradually closing the hot primary air door until the hot primary air door is completely closed according to the set value, and adjusting the output of the cold smoke fan according to the speed measured by the mill tube anemometer in the closing process of the hot primary air door until the measured speed of the mill tube anemometer is kept unchanged;
step three, after the hot primary air door is completely closed, regulating the output of a cold smoke fan according to the speed measured by the mill tube air speed meter and the oxygen content of the coal mill system measured by the oxygen meter, and finally ensuring that the mill tube air speed and the internal oxygen content of the coal mill meet the requirements;
and step four, gradually reducing the output of the coal feeder until the output of the coal feeder is the lowest, then stopping the coal feeder, performing powder extraction on the coal mill, closing the capacity air and the bypass air of the coal mill after the powder extraction is finished, and then stopping the coal mill.
CN202010247008.3A 2020-03-31 2020-03-31 Explosion-proof system for grinding high-volatile coal by double-inlet and double-outlet coal mill and working method Pending CN111256107A (en)

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CN114308274A (en) * 2021-11-08 2022-04-12 广西投资集团北海发电有限公司 Safe operation method for BBD4060 double-inlet and double-outlet direct-blowing type steel ball-milling lignite

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