CN111841861A - System and method for reducing cold air volume of coal mill - Google Patents
System and method for reducing cold air volume of coal mill Download PDFInfo
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- CN111841861A CN111841861A CN202010717075.7A CN202010717075A CN111841861A CN 111841861 A CN111841861 A CN 111841861A CN 202010717075 A CN202010717075 A CN 202010717075A CN 111841861 A CN111841861 A CN 111841861A
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- pipeline
- heat exchanger
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- coal mill
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B02—CRUSHING, PULVERISING, OR DISINTEGRATING; PREPARATORY TREATMENT OF GRAIN FOR MILLING
- B02C—CRUSHING, PULVERISING, OR DISINTEGRATING IN GENERAL; MILLING GRAIN
- B02C23/00—Auxiliary methods or auxiliary devices or accessories specially adapted for crushing or disintegrating not provided for in preceding groups or not specially adapted to apparatus covered by a single preceding group
- B02C23/18—Adding fluid, other than for crushing or disintegrating by fluid energy
- B02C23/24—Passing gas through crushing or disintegrating zone
- B02C23/26—Passing gas through crushing or disintegrating zone characterised by point of gas entry or exit or by gas flow path
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B02—CRUSHING, PULVERISING, OR DISINTEGRATING; PREPARATORY TREATMENT OF GRAIN FOR MILLING
- B02C—CRUSHING, PULVERISING, OR DISINTEGRATING IN GENERAL; MILLING GRAIN
- B02C23/00—Auxiliary methods or auxiliary devices or accessories specially adapted for crushing or disintegrating not provided for in preceding groups or not specially adapted to apparatus covered by a single preceding group
- B02C23/18—Adding fluid, other than for crushing or disintegrating by fluid energy
- B02C23/24—Passing gas through crushing or disintegrating zone
- B02C23/34—Passing gas through crushing or disintegrating zone gas being recirculated to crushing or disintegrating zone
Abstract
The invention discloses a system and a method for reducing the cold air quantity of a coal mill, wherein the system comprises the coal mill, the coal mill is communicated with a hot primary air passage of the coal mill and an air powder pipeline at the outlet of the coal mill, and a steam heat exchanger is arranged in the hot primary air passage of the coal mill and communicated with a boiler barrel; the boiler barrel is respectively communicated with a steam pipeline and a water return pipeline which are communicated with a wind powder pipeline heat exchanger; the booster pump is installed on the return water pipeline. The method comprises the following steps: working medium water in the steam heat exchanger absorbs redundant heat in a primary hot air channel of the coal mill to become steam and enters a boiler barrel, then enters the air powder pipeline heat exchanger through a steam pipeline to heat an air-powder mixture passing through the air powder pipeline heat exchanger, the steam is changed into water after heat exchange is finished, and the water is sent back to the boiler barrel through a water return pipeline by a booster pump and then enters the steam heat exchanger to carry out the next round of heat exchange. The invention realizes the reduction of the input amount of the cold air of the coal mill, reduces the primary air rate, improves the operation economy of the boiler and has higher system operation safety.
Description
Technical Field
The invention relates to a system and a method, in particular to a system and a method for reducing the cold air volume of a coal mill.
Background
The coal mill is one of important auxiliary equipment of a coal-fired power plant boiler, is used as powder making equipment for changing raw coal into qualified coal powder, and plays roles of grinding, conveying and drying the coal powder.
When the temperature of the hot primary air is higher than that required by drying of raw coal in the coal mill, cold air is required to be doped to reduce to a reasonable temperature and then the raw coal is conveyed into the coal mill, so that the primary air quantity entering a boiler is increased, the primary air rate is increased, the combustion of pulverized coal in the boiler is delayed, the center of combustion flame is higher, the exhaust smoke temperature is higher, the running economy of the boiler is reduced, and the power consumption rate of a primary fan is increased.
Meanwhile, the outlet temperature of the coal mill is closely related to the economy and safety of the boiler, so that the outlet temperature of the coal mill is improved, and the ignition heat can be effectively reduced. In the prior art, hot air is often blown directly into the mixture to heat the mixture. However, the reverse blowing of hot air causes negative pressure to be formed in the air powder pipeline at the outlet of the coal mill, and auxiliary equipment such as a blower and the like is required to be added for normally discharging the air powder mixture, so that the problems of great increase of investment cost, improvement of maintenance cost and the like are caused; moreover, the air-powder mixture has a plurality of volatile components, and the oxygen content and the temperature are increased due to the blowing of hot air, so that the high-volatility coal powder is easy to self-ignite, and extremely high potential safety hazards exist.
Disclosure of Invention
In order to overcome the defects of the prior art, the invention provides a system and a method for reducing the cold air quantity of a coal mill.
In order to solve the technical problems, the invention adopts the technical scheme that: a system for reducing the cold air quantity of a coal mill comprises the coal mill, a steam heat exchanger, a boiler barrel, a steam pipeline, a water return pipeline, an air-powder pipeline heat exchanger and a booster pump;
the coal mill is respectively communicated with a coal mill hot primary air channel and a coal mill outlet air powder channel, the steam heat exchanger is arranged in the coal mill hot primary air channel, and the steam heat exchanger is communicated with the boiler barrel; the boiler barrel is respectively communicated with a steam pipeline and a water return pipeline, the steam pipeline is connected with a water inlet of the ventilation powder pipeline heat exchanger, and the water return pipeline is communicated with a water outlet of the ventilation powder pipeline heat exchanger; the air powder pipeline heat exchanger is arranged on an air powder pipeline of the coal mill, and the booster pump is arranged on the water return pipeline;
the coal mill hot primary air channel is also communicated with a cold air channel, a cold air adjusting door is installed on the cold air channel, and a hot air adjusting door is installed on the coal mill hot primary air channel.
Furthermore, a first stop valve is arranged on the steam pipeline, a second stop valve is arranged on the water return pipeline, and the second stop valve is positioned on the water inlet side of the booster pump.
Furthermore, the water return pipeline is also provided with a check valve and an electric regulating valve, the check valve is positioned on the water outlet side of the booster pump, and the electric regulating valve is positioned on the water outlet side of the check valve.
Furthermore, the air-powder pipeline heat exchanger is a sleeve heat exchanger which is sleeved on an air-powder pipeline at the outlet of the coal mill.
A working method of a system for reducing the cold air volume of a coal mill comprises the following steps:
working medium water in the steam heat exchanger absorbs redundant heat of hot air entering the air duct in a primary hot air duct of the coal mill, the working medium water is heated and evaporated into steam and enters a boiler barrel, then enters the air-powder pipeline heat exchanger through the steam duct, heats an air-powder mixture flowing out of the air-powder pipeline at the outlet of the coal mill, the steam is changed into water after heat exchange is completed, and the water is sent back to the boiler barrel through a booster pump by a water return pipeline and then enters the steam heat exchanger for next heat exchange.
Further, the water quantity adjusting process of the working medium water in the steam heat exchanger is as follows:
when the load of the coal mill is high, the water pumping quantity of the booster pump is increased, the water quantity of working medium water flowing back to the steam heat exchanger from the air powder pipeline heat exchanger is increased, and further more heat is absorbed from a hot primary air channel of the coal mill;
when the load of the coal mill is low, the water pumping quantity of the booster pump is reduced, the quantity of the working medium water flowing back to the steam heat exchanger from the air-powder pipeline heat exchanger is reduced, and then less heat is absorbed from a primary hot air duct of the coal mill;
in the water quantity adjusting process of the working medium water, the total hot air quantity entering the hot primary air passage of the coal mill is inconvenient to keep, so that the booster pump is matched with a hot air adjusting door of the coal mill according to the specific working requirement of the coal mill, and the water quantity of the working medium water in the reflux steam heat exchanger is reasonably adjusted and controlled.
The invention discloses a system and a method for reducing the cold air volume of a coal mill, wherein working medium water is used as a heat carrier, and redundant heat in a hot primary air duct at the inlet of the coal mill is transferred to an air-powder mixture at the outlet of the coal mill, so that the introduction of the cold air volume of the coal mill is reduced, the primary air rate is reduced, and the power consumption rate of a primary air fan is reduced; the pulverized coal can catch fire in advance after entering the boiler, the central height of flame in the hearth is reduced, the smoke exhaust temperature is further reduced, and the boiler economy is improved. And the heat exchanger is adopted to heat the outlet air-powder mixture in a heat exchange mode, so that the problems of high input cost and increased potential safety hazard caused by the traditional hot air direct blowing of the air-powder mixture are solved.
Drawings
FIG. 1 is a schematic diagram of the system of the present invention.
In the figure: 1. a coal mill; 2. a coal mill hot primary air duct; 3. an air powder pipeline at the outlet of the coal mill; 4. a steam heat exchanger; 5. a drum; 6. a steam line; 7. a water return pipe; 8. a wind powder pipeline heat exchanger; 9. a booster pump; 10. a cold air adjusting door; 11. a cold air duct; 12. a hot air adjusting door; 13. a first stop valve; 14. a second stop valve; 15. a check valve; 16. an electric regulating valve.
Detailed Description
The present invention will be described in further detail with reference to the accompanying drawings and specific embodiments.
The system for reducing the cold air quantity of the coal mill shown in fig. 1 comprises the coal mill 1, a steam heat exchanger 4, a boiler barrel 5, a steam pipeline 6, a water return pipeline 7, an air-powder pipeline heat exchanger 8 and a booster pump 9;
the coal mill 1 is respectively communicated with a coal mill hot primary air passage 2 and a coal mill outlet air dust pipeline 3, wherein a steam heat exchanger 4 is arranged in the coal mill hot primary air passage 2 so that working medium water in the steam heat exchanger 4 can absorb redundant heat of hot primary air, and the steam heat exchanger 4 is communicated with a drum 5 and is used for steam-water separation and steam purification by the drum 5; the boiler barrel 5 is respectively communicated with a steam pipeline 6 and a water return pipeline 7, the steam pipeline 6 is communicated with a water inlet of an air-powder pipeline heat exchanger 8, and the air-powder pipeline heat exchanger 8 is arranged on an air-powder pipeline 3 of the coal mill, so that steam enters the ventilation-powder pipeline heat exchanger 8 through the steam pipeline 6 to heat an air-powder mixture at an outlet; meanwhile, the water return pipeline 7 is communicated with a water outlet of the wind powder pipeline heat exchanger 8, so that steam is changed into water after heat exchange, continuously flows back into the drum 5 from the water return pipeline 7, and then enters the steam heat exchanger 4 for next heat exchange; moreover, a booster pump 9 is arranged on the water return pipeline 7 to pump water into the drum 5 and regulate the water quantity;
for the wind powder pipeline heat exchanger 8, a double-pipe heat exchanger is adopted, and the double-pipe heat exchanger is sleeved on the wind powder pipeline 3 at the outlet of the coal mill, so that the outlet wind powder mixture is heated in a heat exchange mode without being in direct contact with the wind powder mixture, spontaneous combustion is avoided on the premise of not influencing the normal discharge of the wind powder mixture, and the safety is greatly improved.
Meanwhile, the primary hot air duct 2 is also communicated with a cold air duct 11, a cold air adjusting door 10 is installed on the cold air duct 11, a hot air adjusting door 12 is installed on the primary hot air duct 2 of the coal mill, and the arrangement and installation of the cold air adjusting door 10 and the hot air adjusting door 12 are the prior art.
In addition, stop valves are respectively arranged on the steam pipeline 6 and the water return pipeline 7, so that when the coal mill 1 stops operating, the pipelines are closed, at the moment, the booster pump 9 stops operating, and valves on the steam pipeline 6 and the water return pipeline 7 are both closed, so that the system is isolated; namely: a first stop valve 13 is arranged on the steam pipeline 6, a second stop valve 14 is arranged on the water return pipeline 7, the first stop valve and the second stop valve can adopt drain valves, steam leakage can be prevented to the maximum extent, and meanwhile, the second stop valve 14 is arranged on the water inlet side of the booster pump 9.
Furthermore, the water return pipeline 7 is also provided with a check valve 15 and an electric regulating valve 16, the check valve 15 is positioned on the water outlet side of the booster pump 9, water flow is prevented from returning reversely, and safety is improved; the electric regulating valve 16 is positioned at the water outlet side of the check valve 15 and is matched with the booster pump 9 to regulate and control the amount of the return water.
For the system for reducing the cold air volume of the coal mill, which is disclosed by the invention, the specific working method comprises the following steps:
working medium water in the steam heat exchanger 4 absorbs redundant heat of hot air entering the air channel in the coal mill hot primary air channel 2, the working medium water is heated and evaporated into steam and enters the boiler barrel 5, then the steam enters the air powder pipeline heat exchanger 8 through the steam pipeline 6, the air powder mixture flowing out of the air powder pipeline 3 at the outlet of the coal mill is heated, the steam is changed into water after heat exchange is completed, the water is sent back to the boiler barrel 5 through the booster pump 9 by the water return pipeline 7, and then the water enters the steam heat exchanger 4 for next heat exchange.
Wherein, the water quantity regulating process of the working medium water in the steam heat exchanger 4 is as follows:
when the load of the coal mill 1 is high, the water pumping quantity of the booster pump 9 is increased, the water quantity of the working medium water flowing back to the steam heat exchanger 4 from the air powder pipeline heat exchanger 8 is increased, and further more heat is absorbed from the coal mill hot primary air channel 2;
when the load of the coal mill 1 is low, the water pumping quantity of the booster pump 9 is reduced, the water quantity of the working medium water flowing back to the steam heat exchanger 4 from the air dust pipeline heat exchanger 8 is reduced, and then less heat is absorbed from the coal mill primary hot air duct 2;
in the water quantity adjusting process of the working medium water, the total hot air quantity entering the hot primary air duct 2 of the coal mill is inconvenient to keep, so that the booster pump 9 is matched with the hot air adjusting door 12 of the coal mill according to the specific working requirement of the coal mill 1, and the water quantity of the working medium water in the reflux steam heat exchanger 4 is reasonably adjusted and controlled.
For the system and the method for reducing the cold air quantity of the coal mill, disclosed by the invention, for the coal mill needing to be doped with cold air, the purpose of reducing the cold air quantity of the coal mill can be realized by transferring redundant heat in hot primary air from a hot primary air duct to an air powder pipeline at the outlet of the coal mill through working medium water without doping cold air; further reducing the primary air rate and reducing the power consumption rate of the primary fan; the reduction of the primary air rate enables the pulverized coal to catch fire in advance after entering the boiler, the central height of flame in a hearth can be reduced, the exhaust gas temperature is reduced, and the operating economy of the boiler is obviously improved; meanwhile, the air-powder mixture at the outlet is heated in an indirect heating mode, the traditional hot air direct contact heating mode is abandoned, auxiliary equipment such as an air blower is not needed, the input cost and the maintenance cost are reduced, meanwhile, the spontaneous combustion phenomenon of the coal powder is greatly reduced, and the safety of the system operation is ensured.
The above embodiments are not intended to limit the present invention, and the present invention is not limited to the above examples, and those skilled in the art may make variations, modifications, additions or substitutions within the technical scope of the present invention.
Claims (6)
1. The utility model provides a system for reduce coal pulverizer cold air flow, includes coal pulverizer (1), its characterized in that: the device also comprises a steam heat exchanger (4), a boiler barrel (5), a steam pipeline (6), a water return pipeline (7), a wind powder pipeline heat exchanger (8) and a booster pump (9);
the coal mill (1) is respectively communicated with a coal mill hot primary air passage (2) and a coal mill outlet air dust pipeline (3), the steam heat exchanger (4) is arranged in the coal mill hot primary air passage (2), and the steam heat exchanger (4) is communicated with the boiler barrel (5); the boiler barrel (5) is respectively communicated with a steam pipeline (6) and a water return pipeline (7), the steam pipeline (6) is communicated with a water inlet of the wind-powder pipeline heat exchanger (8), and the water return pipeline (7) is communicated with a water outlet of the wind-powder pipeline heat exchanger (8); the air-powder pipeline heat exchanger (8) is arranged on an air-powder pipeline (3) of the coal mill, and the booster pump (9) is arranged on the water return pipeline (7);
the coal mill primary hot air passage (2) is also communicated with a cold air passage (11), a cold air adjusting door (10) is installed on the cold air passage (11), and a hot air adjusting door (12) is installed on the coal mill primary hot air passage (2).
2. The system for reducing cool air volume of a coal pulverizer of claim 1, wherein: a first stop valve (13) is arranged on the steam pipeline (6), a second stop valve (14) is arranged on the water return pipeline (7), and the second stop valve (14) is located on the water inlet side of the booster pump (9).
3. The system for reducing cool air volume of a coal pulverizer of claim 2, wherein: the water return pipeline (7) is further provided with a check valve (15) and an electric adjusting valve (16), the check valve (15) is located on one water outlet side of the booster pump (9), and the electric adjusting valve (16) is located on one water outlet side of the check valve (15).
4. The system for reducing cool air volume of a coal pulverizer of claim 3, wherein: the air powder pipeline heat exchanger (8) is a sleeve heat exchanger which is sleeved on the air powder pipeline (3) at the outlet of the coal mill.
5. The method for operating a system for reducing cool air volume in a coal pulverizer as defined in any one of claims 1-4, wherein: the working method comprises the following steps:
working medium water in the steam heat exchanger (4) absorbs hot-blast surplus heat that gets into in this wind channel in coal pulverizer hot primary air duct (2), and working medium water is heated and evaporates to become steam and gets into boiler barrel (5), again through steam conduit (6) get into in wind powder pipeline heat exchanger (8), heat the wind powder mixture that flows through coal pulverizer export wind powder pipeline (3), become water after the steam accomplishes the heat transfer, send back boiler barrel (5) through booster pump (9) by return water pipeline (7), reentrant steam heat exchanger (4) in carry out next round of heat transfer.
6. The method of operating a system for reducing cool air flow in a coal pulverizer of claim 5, wherein: the water quantity adjusting process of the working medium water in the steam heat exchanger (4) is as follows:
when the load of the coal mill (1) is high, the water pumping quantity of the booster pump (9) is increased, the water quantity of the working medium which flows back to the steam heat exchanger (4) from the pulverized coal pipeline heat exchanger (8) is increased, and further more heat is absorbed from the coal mill hot primary air passage (2);
when the load of the coal mill (1) is low, the water pumping quantity of the booster pump (9) is reduced, the water quantity of the working medium water flowing back to the steam heat exchanger (4) from the air dust pipeline heat exchanger (8) is reduced, and then less heat is absorbed from the coal mill hot primary air passage (2);
in the water quantity adjusting process of the working medium water, the total hot air quantity entering the hot primary air duct (2) of the coal mill is inconvenient to keep, so that the booster pump (9) is matched with the hot air adjusting door (12) of the coal mill according to the specific working requirement of the coal mill (1), and the water quantity of the working medium water in the backflow steam heat exchanger (4) is reasonably adjusted and controlled.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202010717075.7A CN111841861A (en) | 2020-07-23 | 2020-07-23 | System and method for reducing cold air volume of coal mill |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202010717075.7A CN111841861A (en) | 2020-07-23 | 2020-07-23 | System and method for reducing cold air volume of coal mill |
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| Publication Number | Publication Date |
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| CN111841861A true CN111841861A (en) | 2020-10-30 |
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| CN202010717075.7A Pending CN111841861A (en) | 2020-07-23 | 2020-07-23 | System and method for reducing cold air volume of coal mill |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113294799A (en) * | 2021-05-27 | 2021-08-24 | 东方电气集团东方锅炉股份有限公司 | Hot primary air and air-powder mixture heat exchange system |
-
2020
- 2020-07-23 CN CN202010717075.7A patent/CN111841861A/en active Pending
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113294799A (en) * | 2021-05-27 | 2021-08-24 | 东方电气集团东方锅炉股份有限公司 | Hot primary air and air-powder mixture heat exchange system |
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