CN107327833B - Low NO of boiler powder process exhaust gas x Combustion system - Google Patents
Low NO of boiler powder process exhaust gas x Combustion system Download PDFInfo
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- CN107327833B CN107327833B CN201710698630.4A CN201710698630A CN107327833B CN 107327833 B CN107327833 B CN 107327833B CN 201710698630 A CN201710698630 A CN 201710698630A CN 107327833 B CN107327833 B CN 107327833B
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- 239000000843 powder Substances 0.000 title claims abstract description 105
- 238000002485 combustion reaction Methods 0.000 title claims abstract description 50
- 238000000034 method Methods 0.000 title claims abstract description 10
- 230000008569 process Effects 0.000 title claims abstract description 9
- 239000003245 coal Substances 0.000 claims abstract description 191
- 238000003860 storage Methods 0.000 claims abstract description 36
- 238000000926 separation method Methods 0.000 claims abstract description 30
- 239000000463 material Substances 0.000 claims abstract description 29
- 238000010298 pulverizing process Methods 0.000 claims description 19
- 239000002817 coal dust Substances 0.000 claims description 14
- 238000003801 milling Methods 0.000 claims description 4
- 230000000694 effects Effects 0.000 abstract description 7
- 239000007789 gas Substances 0.000 description 92
- 239000002245 particle Substances 0.000 description 18
- 230000008859 change Effects 0.000 description 5
- 238000005516 engineering process Methods 0.000 description 5
- 229910000831 Steel Inorganic materials 0.000 description 4
- 239000010959 steel Substances 0.000 description 4
- 239000011882 ultra-fine particle Substances 0.000 description 4
- 230000009471 action Effects 0.000 description 2
- 230000002411 adverse Effects 0.000 description 2
- 239000000446 fuel Substances 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 238000005457 optimization Methods 0.000 description 2
- 238000010248 power generation Methods 0.000 description 2
- 230000001681 protective effect Effects 0.000 description 2
- 230000001105 regulatory effect Effects 0.000 description 2
- 230000009466 transformation Effects 0.000 description 2
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 1
- UGFAIRIUMAVXCW-UHFFFAOYSA-N Carbon monoxide Chemical compound [O+]#[C-] UGFAIRIUMAVXCW-UHFFFAOYSA-N 0.000 description 1
- 229910052799 carbon Inorganic materials 0.000 description 1
- 239000003034 coal gas Substances 0.000 description 1
- 239000002131 composite material Substances 0.000 description 1
- 239000012141 concentrate Substances 0.000 description 1
- 239000010419 fine particle Substances 0.000 description 1
- 239000003546 flue gas Substances 0.000 description 1
- 239000010881 fly ash Substances 0.000 description 1
- 230000008676 import Effects 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- 238000011044 inertial separation Methods 0.000 description 1
- 238000012432 intermediate storage Methods 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 238000002360 preparation method Methods 0.000 description 1
- 238000009423 ventilation Methods 0.000 description 1
- 239000002912 waste gas Substances 0.000 description 1
Classifications
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
- F23C—METHODS OR APPARATUS FOR COMBUSTION USING FLUID FUEL OR SOLID FUEL SUSPENDED IN A CARRIER GAS OR AIR
- F23C5/00—Disposition of burners with respect to the combustion chamber or to one another; Mounting of burners in combustion apparatus
- F23C5/08—Disposition of burners
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
- F23C—METHODS OR APPARATUS FOR COMBUSTION USING FLUID FUEL OR SOLID FUEL SUSPENDED IN A CARRIER GAS OR AIR
- F23C7/00—Combustion apparatus characterised by arrangements for air supply
-
- 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
- F23K3/02—Pneumatic feeding arrangements, i.e. by air blast
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
- F23C—METHODS OR APPARATUS FOR COMBUSTION USING FLUID FUEL OR SOLID FUEL SUSPENDED IN A CARRIER GAS OR AIR
- F23C2201/00—Staged combustion
- F23C2201/20—Burner staging
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
- F23C—METHODS OR APPARATUS FOR COMBUSTION USING FLUID FUEL OR SOLID FUEL SUSPENDED IN A CARRIER GAS OR AIR
- F23C2201/00—Staged combustion
- F23C2201/30—Staged fuel supply
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
- F23K—FEEDING FUEL TO COMBUSTION APPARATUS
- F23K2201/00—Pretreatment of solid fuel
- F23K2201/10—Pulverizing
- F23K2201/1006—Mills adapted for use with furnaces
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
- F23K—FEEDING FUEL TO COMBUSTION APPARATUS
- F23K2201/00—Pretreatment of solid fuel
- F23K2201/10—Pulverizing
- F23K2201/103—Pulverizing with hot gas supply
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
- F23K—FEEDING FUEL TO COMBUSTION APPARATUS
- F23K2203/00—Feeding arrangements
- F23K2203/006—Fuel distribution and transport systems for pulverulent fuel
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
- F23K—FEEDING FUEL TO COMBUSTION APPARATUS
- F23K2203/00—Feeding arrangements
- F23K2203/008—Feeding devices for pulverulent fuel
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
- F23K—FEEDING FUEL TO COMBUSTION APPARATUS
- F23K2203/00—Feeding arrangements
- F23K2203/20—Feeding/conveying devices
- F23K2203/201—Feeding/conveying devices using pneumatic means
Abstract
The application provides a low NO in exhaust gas of boiler powder process x The combustion system comprises a raw coal bin, a coal mill, a coarse powder separator, a fine powder separator, a coal powder storage bin, a coal powder separation device and a boiler burner; the discharge port of the raw coal bin is communicated with the feed port of the coal mill, and the discharge port of the coal mill is communicated with the material inlet of the coarse powder separator; the mixed gas outlet of the coarse powder separator is communicated with the feed inlet of the fine powder separator, and the material outlet of the coarse powder separator is communicated with the feed inlet of the coal mill; the mixed gas outlet of the fine powder separator is communicated with the pulverized coal separating device, and the material outlet of the fine powder separator is communicated with the inlet of the pulverized coal storage bin; the mixed gas outlet of the pulverized coal separating device is communicated with the boiler burner, or alternatively, the mixed gas outlet of the pulverized coal separating device is communicated with the boiler burner, and the material outlet of the mixed gas outlet is communicated with the inlet of the pulverized coal storage bin. The combustion system of the application has the following effects: the structure is simple, the operation is convenient, the powder process exhaust gas can be efficiently combusted, and the low NOx emission is realized.
Description
Technical Field
The application relates to the technical field of thermal power generation, in particular to a boiler pulverizing exhaust gas low NO x A combustion system.
Background
The middle bin type pulverizing system based on the steel ball coal mill is the most widely used pulverizing system in a pulverized coal boiler of a power station, wherein pulverized coal gas at an outlet of the steel ball coal mill still contains about 10-15% of superfine pulverized coal particles in exhaust gas after being separated by a traditional fine powder separator, and the treatment of the exhaust gas containing the superfine particles always puzzles the fire power generation industry and boiler combustion engineering technicians.
At present, this exhaust gas is usually fed to the boiler burnerCombustion is carried out in the tertiary air nozzle. Because the powder making exhaust gas flow is larger, the coal powder concentration is lower, and the operation mode and the quantity change of the coal mill are more frequent, the adverse effect on the operation of the boiler can be caused when the powder making exhaust gas is sent into the boiler, and the main appearance is that: (1) The feeding of the exhaust gas can reduce the combustion stability of the boiler, thereby influencing the operation safety of the boiler; (2) The feeding of the coal pulverizing exhaust gas can increase the carbon content of the fly ash of the boiler, so that the combustion efficiency of fuel and the thermal efficiency of a boiler unit are reduced; (3) Traditional powder preparation exhaust gas feeding and burning modes can lead NO at the outlet of a boiler furnace x The production amount is obviously increased, thereby affecting the operation of a downstream denitration system and NO x Is discharged after reaching the standard; (4) The feeding of the coal pulverizing exhaust gas can also cause adverse effect on the temperature characteristics of the superheated steam and the reheat steam of the boiler, and reduce the adaptability of the boiler unit to the coal quality characteristics and the load change.
In view of the above, there is a strong need for a low NO, compact structure, convenient operation, and high efficiency in combustion of the exhaust gas from the coal pulverizing process x The vented system solves the problems in the prior art.
Disclosure of Invention
The application aims to provide a system which has a simple structure, is convenient to operate, can efficiently burn coal pulverizing exhaust gas and realize low NOx emission, and has the following specific technical scheme:
low NO of boiler powder process exhaust gas x The combustion system comprises a raw coal bin, a coal mill, a coarse powder separator, a fine powder separator, a coal powder storage bin, a coal powder separation device and a boiler combustor;
the discharge port of the raw coal bin is communicated with the feed port of the coal mill through a coal feeder, and the discharge port of the coal mill is communicated with the material inlet of the coarse powder separator;
the mixed gas outlet of the coarse powder separator is communicated with the feed inlet of the fine powder separator, and the material outlet of the coarse powder separator is communicated with the feed inlet of the coal mill;
the mixed gas outlet of the fine powder separator is communicated with the feed inlet of the pulverized coal separation device, and the material outlet of the fine powder separator is communicated with the inlet of the pulverized coal storage bin;
the mixed gas outlet of the pulverized coal separation device is communicated with the boiler burner, or the mixed gas outlet of the pulverized coal separation device is communicated with the boiler burner, and the material outlet of the pulverized coal separation device is communicated with the inlet of the pulverized coal storage bin.
In the above technical solution, preferably, the pulverized coal separation device includes a separator cylinder and a rotary impeller device;
the separator cylinder body comprises a body with a cavity, and a gas exhaust inlet, an air outlet and a coal dust outlet which are all arranged on the body, wherein the gas exhaust inlet is communicated with the cavity and a mixed gas outlet of the fine powder separator, and the gas exhaust entering from the gas exhaust inlet tangentially enters into the cavity; the air outlet is communicated with the cavity and an over-fire air nozzle or a top over-fire air nozzle of the boiler burner; the coal dust outlet is communicated with the inlet of the coal dust storage bin;
the rotary impeller device comprises a rotary impeller and a motor, the rotary impeller provides rotary momentum for the airflow of the cavity, and the rotary impeller is arranged in the cavity; the motor provides rotary power for the rotary impeller, and the motor is arranged on the outer wall of the body.
In the above technical solution, preferably, the pulverized coal outlet has a tapered structure with a wide upper part and a narrow lower part, the upper end of the tapered structure is connected with the lower end of the main body and is communicated with the cavity, and the lower end of the tapered structure is communicated with the inlet of the pulverized coal storage bin.
In the above technical scheme, preferably, the exhaust gas inlet is arranged at the upper part of the body, the air outlet is arranged at the top center position of the body, and the upper part of the body is also provided with an explosion-proof valve.
In the above technical solution, preferably, the rotating impeller is disposed at an upper portion of the cavity through a supporting frame, and the rotating impeller is located below the exhaust gas inlet;
the motor is a variable frequency motor, a first conical gear is arranged at the end part of an output shaft of the motor, and a second conical gear matched with the first conical gear is arranged at the end part of a rotating shaft of the rotating impeller.
In the above technical solution, preferably, the air locking devices are disposed on a pipeline where the material outlet of the fine powder separator is communicated with the inlet of the pulverized coal storage bin and on a pipeline where the pulverized coal outlet is communicated with the inlet of the pulverized coal storage bin.
In the above technical solution, preferably, the pulverized coal separation device includes a concentrator body and an impeller rotating member;
the concentrator body comprises a barrel body with a cavity, and a spent gas inlet pipe, a dilute phase airflow outlet pipe and a concentrated phase airflow outlet pipe which are arranged on the barrel body at the same time, wherein the spent gas inlet pipe is communicated with the cavity and a mixed gas outlet of the fine powder separator, and the spent gas entering from the spent gas inlet pipe tangentially enters the cavity; the dilute phase airflow eduction tube is communicated with an over-fire air nozzle or a top over-fire air nozzle of the boiler burner; the dense-phase airflow eduction tube is communicated with a reburning nozzle above a main burning nozzle of the boiler burner;
the impeller rotating part comprises an impeller and a motor, the impeller provides rotating momentum for the airflow in the cavity, and the impeller is arranged in the cavity; the motor provides rotary power for the impeller, and the motor is arranged on the outer wall of the cylinder body.
In the above technical scheme, preferably, the motor is a variable frequency motor;
the tail end of the output shaft of the motor is provided with a conical gear A, and the end part of the rotating shaft of the impeller is provided with a conical gear B matched with the conical gear A;
alternatively, the impeller is mounted on the output shaft of the motor.
In the above technical scheme, preferably, an electromagnetic valve and a flow measuring device are arranged on an inlet pipeline of an overfire air nozzle of the boiler combustor;
the up-down swing angle of the over-fire air nozzle is +/-30 degrees, and the horizontal swing angle of the over-fire air nozzle is +/-15 degrees.
In the above technical solution, preferably, electric air doors are arranged on the pipeline of the air outlet communicated with the overfire air nozzle of the boiler burner and on the pipeline of the exhaust gas inlet pipe communicated with the mixed gas outlet of the fine powder separator;
the inlet of the electric air door is also communicated with the output port of the coal feeder and/or the coal dust storage bin.
The high-efficiency low-NOx combustion system for preparing the coal by using the furnace provided by the application has the following effects:
1. the coal powder boiler pulverizing exhaust gas high-efficiency low NOx combustion system technology can be used for the transformation of an active coal-fired boiler intermediate storage type pulverizing exhaust gas combustion system so as to improve the adaptability of a boiler and a pulverizing system to coal types and loads, the operation reliability, the operation flexibility and the economy, and can also be used for the design of a newly built coal-fired power station boiler combustion system and a pulverizing system.
2. Compared with the traditional coal pulverizing exhaust gas combustion technology, the system provided by the application has the following technical advantages: (1) the combustion stability and the combustion efficiency of ultrafine particles in exhaust gas can be obviously improved; (2) the NOx generation amount at the outlet of the boiler hearth can be obviously reduced; (3) by laying the defending combustion belt on the upper area of the main burner, the flue gas temperature characteristic of the outlet of the boiler hearth can be obviously improved, and the overheat steam temperature and reheat steam temperature characteristic of the boiler can be further effectively improved; (4) when the load of the coal is changed, the high-efficiency combustion, low NOx emission and coordination of superheated steam and re-steam temperature adjustment can be realized, so that the reliability and the flexibility of the operation of the pulverizing and combustion system of the boiler unit are obviously improved.
3. The combustion system of the application is mainly based on the technology of high-efficiency separation and concentration of superfine pulverized coal in the coal-making exhaust gas (namely the pulverized coal separation device in the application), and the treatment of the coal-making exhaust gas is mainly carried out in two modes: (1) separating ultrafine coal dust particles in the coal dust exhaust gas by utilizing a high-efficiency separator technology, then directly entering the separated ultrafine particles into a primary air nozzle (a main burner) in a boiler burner through a coal dust storage bin and a coal feeder for combustion, and sending air containing a very small amount of ultrafine particles into an OFA (top burning air) nozzle or an SOFA (independent top burning air) nozzle of the boiler burner; (2) the fine particle efficient concentration technology is utilized to concentrate the powder making exhaust gas to obtain thick and thin two air flows, then the thick-phase superfine pulverized coal particle air flow with more pulverized coal particles is used as reburning fuel to be sent to a reburning nozzle at the upper part of a primary air nozzle of the boiler burner, and the thin-phase air flow with less pulverized coal particles is used as burning air to be sent to an OFA (top burning air) nozzle or an SOFA (independent top burning air) nozzle of the boiler burner.
4. In order to ensure that the boiler has enough combustion adjustment means to realize high-efficiency low-NOx combustion when the characteristics, load, operation mode of coal mills and input number of coal mills are changed, OFA (top burning wind) or SOFA (independent top burning wind) nozzles are designed into nozzles capable of swinging in the vertical and horizontal directions during engineering implementation, and the arrangement height of the nozzles is optimized according to the specific coal characteristics change range; an electric regulating valve and a flow measuring device are arranged in front of the inlet of an OFA (top burning wind) or SOFA (independent top burning wind) nozzle so as to carry out on-site adjustment and optimization when the coal types and loads change.
In addition to the objects, features and advantages described above, the present application has other objects, features and advantages. The application will be described in further detail with reference to the accompanying drawings.
Drawings
The accompanying drawings, which are included to provide a further understanding of the application and are incorporated in and constitute a part of this specification, illustrate embodiments of the application and together with the description serve to explain the application. In the drawings:
FIG. 1 is a low NO off-gas of the boiler milling in example 1 x The structure of the combustion system is simplified;
FIG. 2 is a schematic view of the pulverized coal separating device in FIG. 1;
FIG. 3 is a low NO off-gas of the boiler milling in example 2 x The structure of the combustion system is simplified;
FIG. 4 is a schematic view of the pulverized coal separating device in FIG. 2;
1. raw coal bin, 2, coal mill, 3, coarse powder separator, 4, fine powder separator, 5, coal powder storage bin, 6, coal powder separating device, 6.1, separator cylinder, 6.11, body, 6.111, cavity, 6.12, exhaust gas inlet, 6.13, air outlet, 6.14, coal powder outlet, 6.2, rotary impeller device, 6.21, rotary impeller, 6.22, motor, 6.23, support frame, 6.3, explosion-proof valve, 6.4, concentrator body, 6.41, cylinder, 6.411, cavity, 6.42, exhaust gas inlet pipe, 6.43, dense phase gas flow eduction tube, 6.44, dilute phase gas flow eduction tube, 6.5, impeller rotating part, 6.51, impeller, 6.52, motor, 7, boiler burner, 7.1, over-fire air nozzle or top over-fire air nozzle, 7.2, main combustion nozzle, 7.3, reburning nozzle, 7.4, flue outlet, 8, coal feeder, 9, gas lock, 10, solenoid valve, 11, electric damper, 12, cold air inlet tube, 13, hot air inlet tube, 14, protective cover.
Detailed Description
Embodiments of the application are described in detail below with reference to the attached drawings, but the application can be implemented in a number of different ways, which are defined and covered by the claims.
Example 1:
low NO of boiler powder process exhaust gas x The combustion system is shown in fig. 1 in detail, and specifically comprises a raw coal bin 1, a coal mill 2, a coarse powder separator 3, a fine powder separator 4, a pulverized coal storage bin 5, a pulverized coal separation device 6 and a boiler burner 7, wherein the specific connection relations are as follows:
the discharge gate of former coal bunker 1 pass through feeder 8 with the feed inlet intercommunication of coal pulverizer 2, the discharge gate of coal pulverizer 2 with the material import intercommunication of coarse powder separator 3. The coal mill 2 is simultaneously connected with a cold air pipeline 12, a hot air pipeline 13 and an electric air door 11.
The mixed gas outlet of the coarse powder separator 3 is communicated with the feed inlet of the fine powder separator 4, and the material outlet of the coarse powder separator 3 is communicated with the feed inlet of the coal mill 2. The feed inlet of the coal mill 2 is also communicated with an external cold air inlet pipe 12 and a hot air inlet pipe 13.
The mixed gas outlet of the fine powder separator 4 is communicated with the feed inlet of the pulverized coal separating device 6, and the material outlet of the fine powder separator 4 is communicated with the inlet of the pulverized coal storage bin 5.
The mixed gas outlet of the pulverized coal separating device 6 is communicated with the boiler burner 7, and the material outlet of the pulverized coal separating device 6 is communicated with the inlet of the pulverized coal storage bin 5. The upper end of the boiler burner is also provided with a flue outlet 7.3.
The structure of the pulverized coal separation device 6 is shown in fig. 2, and specifically includes a separator cylinder 6.1 and a rotary impeller device 6.2, and the detailed structure is as follows:
the separator bowl 6.1 comprises a body 6.11 with a cavity 6.111, a spent air inlet 6.12, an air outlet 6.13 and a pulverized coal outlet 6.14, all arranged on the body 6.11; the exhaust gas inlet 6.12 is arranged at the upper part of the body 6.11 and is used for communicating the cavity 6.111 with the mixed gas outlet of the fine powder separator 4, and the exhaust gas entering from the exhaust gas inlet 6.12 enters the cavity 6.111 tangentially; the air outlet 6.13 is arranged at a top central position of the body 6.11 for communicating the cavity 6.111 with an overfire air nozzle or top overfire air nozzle 7.1 of the boiler burner 7; the pulverized coal outlet 6.14 is communicated with an inlet of the pulverized coal storage bin 5. The upper part of the body 1.1 is also provided with an explosion-proof valve 6.3. The pulverized coal outlet 6.14 is in a conical structure with a wide upper part and a narrow lower part, the upper end of the pulverized coal outlet is connected with the lower end of the body 6.11 and is communicated with the cavity 6.111, and the lower end of the pulverized coal outlet is communicated with the pulverized coal storage bin 5.
The rotary impeller means 6.2 comprises a rotary impeller 6.21 and a motor 6.22, the rotary impeller 6.21 providing a rotational momentum to the air flow of the cavity 6.111, the rotary impeller 6.21 being arranged inside the cavity 6.111; the motor 6.22 provides rotational power for the rotating impeller 6.21, the motor 6.22 being arranged on the outer wall of the body 6.11. The method specifically comprises the following steps:
the rotating impeller 6.21 is arranged at the upper part of the cavity 6.111 by a supporting frame 6.23, and the rotating impeller 6.21 is positioned below the exhaust gas inlet 6.12.
The motor 6.22 is a variable frequency motor, a first bevel gear is arranged at the end part of an output shaft of the motor 6.22, and a second bevel gear matched with the first bevel gear is arranged at the end part of a rotating shaft of the rotating impeller 6.21. Both the first and second bevel gears are disposed inside the boot 14.
The material outlet of the fine powder separator 4 is communicated with the inlet of the pulverized coal storage bin 5, and the pulverized coal outlet 6.14 is communicated with the inlet of the pulverized coal storage bin 5, and the pipeline is provided with an air lock 9.
An electromagnetic valve 10 and a flow measuring device are arranged on an inlet pipeline of an overfire air nozzle 7.1 of the boiler combustor 7; the up-down swing angle of the over-fire air nozzle 7.1 is +/-30 degrees, and the horizontal swing angle is +/-15 degrees.
An electric air door 11 is arranged on a pipeline of the air outlet 6.13 communicated with the over-fire air nozzle 7.1 of the boiler burner 7, and an inlet of the electric air door 11 is also communicated with an output port of the coal feeder 8 and the pulverized coal storage bin 5 at the same time.
The combustion system to which the embodiment is applied specifically includes:
in the intermediate bin type pulverizing system, pulverized coal in an original coal bin 1 enters a coal mill 2 (a steel ball coal mill is adopted here) through a coal feeder 8 or directly enters a main combustion nozzle 7.2 of a boiler combustor 7 through an electric air door 11;
the pulverized coal airflow after being ground enters a material inlet of the coarse powder separator 3 through a discharge hole of the coal mill 2; the pulverized coal airflow is separated into pulverized coal mixed airflow and pulverized coal particles by a coarse powder separator 3, the pulverized coal mixed airflow enters a feed inlet of the fine powder separator 4 through a mixed gas outlet of the coarse powder separator 3, and the pulverized coal particles return to a feed inlet of the coal mill 2 through a material outlet of the coarse powder separator 3 and then enter the pulverizer 2;
the pulverized coal mixed gas flows through the fine powder separator 4 to be separated into a mixed gas flow containing superfine pulverized coal and pulverized coal particles, and the mixed gas flow containing superfine pulverized coal flows through a mixed gas outlet of the fine powder separator 4 to enter a ventilation gas inlet 6.12 of the pulverized coal separation device 6 and then enters a cavity 6.111 of a separator cylinder 6.1 in the pulverized coal separation device 6; the pulverized coal particles enter the inlet of the pulverized coal storage bin 5 through the material outlet of the fine powder separator 4, then enter the pulverized coal storage bin, and then can directly enter the main combustion nozzle 7.2 of the boiler burner 7 through the electric air door 11;
the mixed gas containing superfine coal powder flows through a coal powder separating device 6 to be separated into coal powder particles and air, and the air directly enters an overfire air nozzle of a boiler burner 7 or a top overfire air nozzle 7.1 through an electric air door 11, so that high-efficiency low-NOx combustion based on air classification is realized; the coal powder particles enter the inlet of the coal powder storage bin 5 through the material outlet of the coal powder separation device 6, then enter the coal powder storage bin, and then can directly enter the main combustion nozzle 7.2 of the boiler burner 7 through the electric air door 11.
The over-fire air nozzle or the top over-fire air nozzle is designed as a nozzle capable of swinging in the vertical and horizontal directions, and the arrangement height of the nozzle is optimized according to the specific coal quality characteristic variation range.
An electric regulating valve and a flow measuring device are arranged in front of the inlet of the over-fire air nozzle or the top over-fire air nozzle so as to carry out on-site adjustment and optimization when the coal types and loads change.
By applying the technical scheme of the embodiment, the effect is as follows:
1. the combustion system has simple structure, is used for the intermediate warehouse type pulverizing system, does not occupy large space and does not need to lay complex pipelines, and is convenient for industrialized application.
2. The pulverized coal separation device utilizes a composite mode of inertial separation and rotary impeller separation, greatly improves the pulverized coal separation effect, and specifically comprises the following steps: the exhaust gas flow containing ultrafine coal powder particles rotates at a high speed in the separator cylinder, so that part of ultrafine particles in the gas flow are separated and thrown onto the inner wall surface of the separator cylinder under the action of centrifugal force, and the part of particles fall into the coal powder outlet along the wall surface of the cylinder; the momentum (especially the rotational momentum) of the air flow decays rapidly along with the rotation of the air flow, and at the moment, the air flow in the downlink obtains the rotational momentum again due to the high-speed rotation of the rotating impeller, so that the air flow is separated continuously under the action of centrifugal force, and the efficient low-NOx combustion based on air classification is realized.
3. The combustion system of the embodiment not only can be used for the transformation of the intermediate warehouse type coal-making exhaust gas combustion system of the active coal-fired boiler so as to improve the adaptability of the boiler and the coal-making system to coal types and loads, the operation reliability, the operation flexibility and the economy, but also can be used for the design of the combustion system and the coal-making system of the newly-built coal-fired power station boiler.
Example 2
Low NO of boiler powder process exhaust gas x The combustion system, detailed in fig. 3, differs from embodiment 1 in that:
1. the mixed gas outlet of the pulverized coal separating device 6 is communicated with the gas inlet of the boiler burner 7.
2. The structure of the pulverized coal separation device is shown in fig. 4, and specifically comprises the following components: comprising a concentrator body 6.4 and an impeller rotating part 6.5, the details are as follows:
the concentrator body 6.4 comprises a barrel 6.41 with a cavity 6.411, and a spent gas inlet pipe 6.42, a concentrated phase gas flow outlet pipe 6.43 and a dilute phase gas flow outlet pipe 6.44 which are simultaneously arranged on the barrel 6.41, wherein the spent gas inlet pipe 6.42 is communicated with the cavity 6.411 and a mixed gas outlet of the fine powder separator 4, and the spent gas entering by the spent gas inlet pipe 6.42 tangentially enters the cavity 6.411; the dilute phase gas flow eduction tube 6.44 is communicated with an over-fire air nozzle or a top over-fire air nozzle 7.1 of the boiler burner 7; the dense phase gas stream lead-out pipe 6.43 communicates with a reburning nozzle 7.3 above the main combustion nozzle 7.2 of the boiler burner 7. The electric damper 11 is arranged on a pipeline of the exhaust gas inlet pipe 6.42 communicated with the mixed gas outlet of the fine powder separator 4.
The impeller rotation part 6.5 comprises an impeller 6.51 and a motor 6.52, the impeller 6.51 providing rotational momentum for the air flow in the cavity 6.411, the impeller 6.51 being arranged inside the cavity 6.411; the motor 6.52 provides rotational power to the impeller 6.51, the motor 6.52 being arranged on the outer wall of the cylinder 6.41. The motor 6.52 is a variable frequency motor; the impeller 6.51 is mounted on the output shaft of the motor 6.52. The connection of the impeller and the motor may also be in the following manner: the end of the output shaft of the motor 6.52 is provided with a bevel gear A, the end part of the rotating shaft of the impeller 6.51 is provided with a bevel gear B matched with the bevel gear A, and the bevel gear A and the bevel gear B are both arranged inside the protective cover.
The combustion system to which the embodiment is applied specifically includes:
in the intermediate bin type pulverizing system, pulverized coal in an original coal bin 1 enters a coal mill 2 (a steel ball coal mill is adopted here) through a coal feeder 8 or directly enters a main combustion nozzle 7.2 of a boiler combustor 7 through an electric air door 11;
the pulverized coal airflow after being ground enters a material inlet of the coarse powder separator 3 through a discharge hole of the coal mill 2; the pulverized coal airflow is separated into pulverized coal mixed airflow and pulverized coal particles by a coarse powder separator 3, the pulverized coal mixed airflow enters a feed inlet of the fine powder separator 4 through a mixed gas outlet of the coarse powder separator 3, and the pulverized coal particles return to a feed inlet of the coal mill 2 through a material outlet of the coarse powder separator 3 and then enter the pulverizer 2;
the pulverized coal mixed gas flows through the fine powder separator 4 to be separated into mixed gas flow containing superfine pulverized coal and pulverized coal particles, and the mixed gas flow containing superfine pulverized coal flows through a mixed gas outlet of the fine powder separator 4 and the electric air door 11 to directly enter a waste gas inlet pipe 6.42 of the pulverized coal separation device 6 and then enter a cavity 6.411 of a concentrator body 6.4 in the pulverized coal separation device 6; the pulverized coal particles enter the inlet of the pulverized coal storage bin 5 through the material outlet of the fine powder separator 4, then enter the pulverized coal storage bin, and then can directly enter the main combustion nozzle 7.2 of the boiler burner 7 through the electric air door 11;
the mixed gas containing superfine coal dust is separated into concentrated phase gas flow and dilute phase gas flow by the coal dust separating device 6, the concentrated phase gas flow enters a reburning nozzle 7.3 above a main burning nozzle of the boiler burner 7 through a concentrated phase gas flow eduction tube 6.43, and the dilute phase gas flow enters an over-fire air nozzle or a top over-fire air nozzle 7.1 of the boiler burner 7 through a dilute phase gas flow eduction tube 6.44, so that the high-efficiency low NOx burning based on air classification is realized.
The effect of the present embodiment is equivalent to that of the embodiment.
The above description is only of the preferred embodiments of the present application and is not intended to limit the present application, but various modifications and variations can be made to the present application by those skilled in the art. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application should be included in the protection scope of the present application.
Claims (7)
1. Low NO of boiler powder process exhaust gas x A combustion system, characterized in that: comprises a raw coal bin (1), a coal mill (2), a coarse powder separator (3), a fine powder separator (4), a coal powder storage bin (5), a coal powder separation device (6) and a boiler burner (7);
the discharge port of the raw coal bin (1) is communicated with the feed port of the coal mill (2) through a coal feeder (8), and the discharge port of the coal mill (2) is communicated with the material inlet of the coarse powder separator (3);
the mixed gas outlet of the coarse powder separator (3) is communicated with the feed inlet of the fine powder separator (4), and the material outlet of the coarse powder separator (3) is communicated with the feed inlet of the coal mill (2);
the mixed gas outlet of the fine powder separator (4) is communicated with the feed inlet of the pulverized coal separation device (6), and the material outlet of the fine powder separator (4) is communicated with the inlet of the pulverized coal storage bin (5);
the mixed gas outlet of the pulverized coal separation device (6) is communicated with the boiler burner (7), or alternatively, the mixed gas outlet of the pulverized coal separation device (6) is communicated with the boiler burner (7), and the material outlet of the pulverized coal separation device (6) is communicated with the inlet of the pulverized coal storage bin (5);
the pulverized coal separation device (6) comprises a separator cylinder (6.1) and a rotary impeller device (6.2);
the separator cylinder (6.1) comprises a body (6.11) with a cavity (6.111), and a spent gas inlet (6.12), an air outlet (6.13) and a coal dust outlet (6.14) which are all arranged on the body (6.11), wherein the spent gas inlet (6.12) is communicated with the cavity (6.111) and a mixed gas outlet of the fine powder separator (4), and the spent gas entering from the spent gas inlet (6.12) tangentially enters the cavity (6.111); -said air outlet (6.13) communicates with an overfire air nozzle or top overfire air nozzle (7.1) of said cavity (6.111) and said boiler burner (7); the pulverized coal outlet (6.14) is communicated with the inlet of the pulverized coal storage bin (5);
the rotary impeller device (6.2) comprises a rotary impeller (6.21) and a motor (6.22), the rotary impeller (6.21) provides rotary momentum for the airflow of the cavity (6.111), the rotary impeller (6.21) is arranged inside the cavity (6.111), and the rotary impeller (6.21) is positioned below the exhaust gas inlet (6.12); the motor (6.22) provides rotary power for the rotary impeller (6.21), and the motor (6.22) is arranged on the outer wall of the body (6.11);
an electromagnetic valve (10) and a flow measuring device are arranged on an inlet pipeline of an overfire air nozzle (7.1) of the boiler combustor (7);
the up-down swing angle of the over-fire air nozzle (7.1) is +/-30 degrees, and the horizontal swing angle is +/-15 degrees.
2. The boiler pulverizing exhaust gas low-NO according to claim 1 x The combustion system is characterized in that the coal dust outlet (6.14) is of a conical structure with a wide upper part and a narrow lower part, the upper end of the coal dust outlet is connected with the lower end of the body (6.11) and is communicated with the cavity (6.111), and the lower end of the coal dust outlet is communicated with the inlet of the coal dust storage bin (5).
3. The boiler milling exhaust gas low NOx combustion system according to claim 1, characterized in that the exhaust gas inlet (6.12) is arranged at the upper part of the body (6.11), the air outlet (6.13) is arranged at the top center position of the body (6.11), and the upper part of the body (1.1) is further provided with an explosion-proof valve (6.3).
4. The boiler milling exhaust gas low NOx combustion system according to claim 1, characterized in that the rotating impeller (6.21) is arranged in the upper part of the cavity (6.111) by means of a support frame (6.23);
the motor (6.22) is a variable frequency motor, a first conical gear is arranged at the end part of an output shaft of the motor (6.22), and a second conical gear matched with the first conical gear is arranged at the end part of a rotating shaft of the rotating impeller (6.21).
5. The boiler pulverizing exhaust gas low-NO according to claim 1 x A combustion system, characterized in that: the material outlet of the fine powder separator (4) is communicated with the inlet of the pulverized coal storage bin (5), and the pulverized coal outlet (6.14) is communicated with the inlet of the pulverized coal storage bin (5) and is provided with an air locking device (9).
6. Low NO of boiler powder process exhaust gas x A combustion system, characterized in that: comprises a raw coal bin (1), a coal mill (2), a coarse powder separator (3), a fine powder separator (4), a coal powder storage bin (5), a coal powder separation device (6) and a boiler burner (7);
the discharge port of the raw coal bin (1) is communicated with the feed port of the coal mill (2) through a coal feeder (8), and the discharge port of the coal mill (2) is communicated with the material inlet of the coarse powder separator (3);
the mixed gas outlet of the coarse powder separator (3) is communicated with the feed inlet of the fine powder separator (4), and the material outlet of the coarse powder separator (3) is communicated with the feed inlet of the coal mill (2);
the mixed gas outlet of the fine powder separator (4) is communicated with the feed inlet of the pulverized coal separation device (6), and the material outlet of the fine powder separator (4) is communicated with the inlet of the pulverized coal storage bin (5);
the pulverized coal separation device (6) comprises a concentrator body (6.4) and an impeller rotating part (6.5);
the concentrator body (6.4) comprises a barrel (6.41) with a cavity (6.411), and a spent gas inlet pipe (6.42), a concentrated phase airflow outlet pipe (6.43) and a dilute phase airflow outlet pipe (6.44) which are simultaneously arranged on the barrel (6.41), wherein the spent gas inlet pipe (6.42) is communicated with a mixed gas outlet of the cavity (6.411) and the fine powder separator (4), and the spent gas entering from the spent gas inlet pipe (6.42) tangentially enters the cavity (6.411); the dilute phase airflow eduction tube (6.44) is communicated with an over-fire air nozzle or a top over-fire air nozzle (7.1) of the boiler burner (7); the dense-phase gas flow eduction tube (6.43) is communicated with a reburning nozzle (7.3) above a main burning nozzle (7.2) of the boiler burner (7);
the impeller rotating part (6.5) comprises an impeller (6.51) and a motor (6.52), the impeller (6.51) provides rotational momentum for the airflow in the cavity (6.411), and the impeller (6.51) is arranged inside the cavity (6.411); the motor (6.52) provides rotary power for the impeller (6.51), and the motor (6.52) is arranged on the outer wall of the cylinder (6.41);
an electromagnetic valve (10) and a flow measuring device are arranged on an inlet pipeline of an overfire air nozzle (7.1) of the boiler combustor (7);
the up-down swing angle of the over-fire air nozzle (7.1) is +/-30 degrees, and the horizontal swing angle is +/-15 degrees.
7. The boiler pulverizing exhaust gas low-NO according to claim 6 x The combustion system is characterized in that the motor (6.52) is a variable frequency motor;
the tail end of the output shaft of the motor (6.52) is provided with a conical gear A, and the end of the rotating shaft of the impeller (6.51) is provided with a conical gear B matched with the conical gear A;
alternatively, the impeller (6.51) is mounted on the output shaft of the motor (6.52).
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| CN1587800A (en) * | 2004-07-15 | 2005-03-02 | 浙江大学 | Method and system for reducing NO discharging by collecting and refiring fine coal powder in tertiary wind |
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| CN1587800A (en) * | 2004-07-15 | 2005-03-02 | 浙江大学 | Method and system for reducing NO discharging by collecting and refiring fine coal powder in tertiary wind |
| CN203044189U (en) * | 2013-01-22 | 2013-07-10 | 无锡联营电力设备有限公司 | Secondary separation device of high-efficiency fine-powder separator |
| CN104344398A (en) * | 2013-07-31 | 2015-02-11 | 烟台龙源电力技术股份有限公司 | Middle storage type hot wind powder feeding and pulverizing system |
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