CN102116484B - Combustion control method and system for lignite-fired unit - Google Patents
Combustion control method and system for lignite-fired unit Download PDFInfo
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- CN102116484B CN102116484B CN201010001611XA CN201010001611A CN102116484B CN 102116484 B CN102116484 B CN 102116484B CN 201010001611X A CN201010001611X A CN 201010001611XA CN 201010001611 A CN201010001611 A CN 201010001611A CN 102116484 B CN102116484 B CN 102116484B
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- 238000002485 combustion reaction Methods 0.000 title claims abstract description 34
- 238000000034 method Methods 0.000 title claims abstract description 25
- UGFAIRIUMAVXCW-UHFFFAOYSA-N Carbon monoxide Chemical compound [O+]#[C-] UGFAIRIUMAVXCW-UHFFFAOYSA-N 0.000 claims abstract description 106
- 239000003546 flue gas Substances 0.000 claims abstract description 106
- 239000003245 coal Substances 0.000 claims abstract description 46
- 239000003077 lignite Substances 0.000 claims abstract description 38
- 230000001105 regulatory effect Effects 0.000 claims abstract description 19
- 239000007789 gas Substances 0.000 claims abstract description 13
- 230000001276 controlling effect Effects 0.000 claims abstract description 11
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 claims description 51
- 239000001301 oxygen Substances 0.000 claims description 51
- 229910052760 oxygen Inorganic materials 0.000 claims description 51
- 239000000203 mixture Substances 0.000 claims description 50
- 239000003595 mist Substances 0.000 claims description 29
- 230000003750 conditioning effect Effects 0.000 claims description 28
- 239000000446 fuel Substances 0.000 claims description 23
- 239000000779 smoke Substances 0.000 claims description 14
- 238000001514 detection method Methods 0.000 claims description 5
- 239000000428 dust Substances 0.000 claims description 5
- 230000008030 elimination Effects 0.000 abstract 1
- 238000003379 elimination reaction Methods 0.000 abstract 1
- 239000002817 coal dust Substances 0.000 description 12
- 238000010586 diagram Methods 0.000 description 12
- 238000005516 engineering process Methods 0.000 description 7
- 235000019504 cigarettes Nutrition 0.000 description 6
- 238000001035 drying Methods 0.000 description 6
- 230000009286 beneficial effect Effects 0.000 description 5
- MWUXSHHQAYIFBG-UHFFFAOYSA-N Nitric oxide Chemical compound O=[N] MWUXSHHQAYIFBG-UHFFFAOYSA-N 0.000 description 3
- 238000004134 energy conservation Methods 0.000 description 3
- 238000005265 energy consumption Methods 0.000 description 3
- 239000000284 extract Substances 0.000 description 2
- 238000010521 absorption reaction Methods 0.000 description 1
- 238000004880 explosion Methods 0.000 description 1
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- 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
Abstract
The invention provides a combustion control method and a system for a lignite-fired unit, and the method comprises the following steps: feeding back flue gas sent out from an outlet of an induced draft fan to an inlet of a primary air fan; and using the primary air fan to mix the fed back flue gas with air sent in from outside, and sending the mixed gas into a boiler for the combustion of lignite through an air preheater and a coal pulverizer. By adopting the technical scheme, a flue gas regulating device is connected between the outlet of the induced draft fan and the inlet of the primary air fan through a flue, and a certain amount of the flue gas is doped into primary air, thereby not only reducing the using amount of the primary air of a boiler and controlling NOx within a qualified range, but also reducing the resistance of a primary air pipeline due to the elimination of a primary air heater and reducing power consumption of the primary air fan.
Description
Technical field
The present invention about the brown coal field of combustion technology, specifically, is method for controlling combustion and the system about a kind of brown coal unit.
Background technology
Brown coal are the most shallow coals of colliery degree, account for 12% left and right of national coal reserves, will become the main source of China's energy.But often moisture is very large due to it, needs an a large amount of wind during burning, makes the primary air flow of input boiler very large, NO
x(nitrogen oxide) is difficult to control, and flue gas loss simultaneously is very large, and boiler efficiency is very low.
The schematic diagram of the combustion control system of the brown coal unit that provides for prior art as shown in Figure 1.Coal pulverizer 104 is connected between boiler 105 primary air fan 103 outlets, overfire air fan 102 outlets connect and boiler 105, realize the air preheat between flue, Secondary Air pipeline, wind pipeline in air preheater 106, deduster 107 is connected between the flue and air-introduced machine 101 entrances of air preheater, and the outlet of air-introduced machine is connected with chimney 108.Because the temperature of the entrance drier of existing medium-speed pulverizer coal burning machine generally can not surpass 400 ℃, therefore, when using pure hot blast to carry out drying, just must the increasing primary air ratio for brown coal being carried out drying, perhaps increase again one-level air preheater raising temperature.
Summary of the invention
In order to solve the problem of primary air flow of the prior art, the invention provides a kind of method for controlling combustion and system of brown coal unit.
On the one hand, the invention provides a kind of method for controlling combustion of brown coal unit, described method comprises:
The flue gas that the air-introduced machine outlet is sent feeds back to the primary air fan entrance;
Described primary air fan mixes the flue gas of feedback with the air sent into of outside, and mist is sent into described boiler by air preheater and coal pulverizer brown coal are burnt.
On the other hand, the present invention also provides a kind of combustion control system of brown coal unit, and described system comprises: boiler, coal pulverizer, air preheater, dust removal machine, air-introduced machine, primary air fan, overfire air fan and chimney; Described system also comprises: flue gas conditioning device;
Described flue gas conditioning device is connected between described air-introduced machine outlet and described primary air fan entrance by flue, and the flue gas that air-introduced machine is sent feeds back to described primary air fan entrance;
Described primary air fan mixes the flue gas of feedback with the air sent into of outside, and mist is sent into described boiler by described air preheater and coal pulverizer brown coal are burnt.
Beneficial effect of the present invention is, be connected between described air-introduced machine outlet and described primary air fan entrance by flue by flue gas conditioning device, mix a certain amount of flue gas in a wind, not only can reduce the use amount of a wind of boiler, and can be with N0
xWithin being controlled at acceptability limit, simultaneously due to the steam air heater of having cancelled a wind, reduce the resistance of a wind pipeline, reduced the power consumption of primary air fan.
Description of drawings
In order to be illustrated more clearly in the embodiment of the present invention or technical scheme of the prior art, the below will do to introduce simply to the accompanying drawing of required use in embodiment or description of the Prior Art, apparently, accompanying drawing in the following describes is only some embodiments of the present invention, for those of ordinary skills, under the prerequisite of not paying creative work, can also obtain according to these accompanying drawings other accompanying drawing.
The schematic diagram of the combustion control system of the brown coal unit that Fig. 1 provides for prior art;
Fig. 2 is the schematic diagram of the combustion control system of brown coal unit provided by the invention;
Fig. 3 is the schematic diagram of the combustion control system of brown coal unit provided by the invention;
Fig. 4 is the schematic diagram of the combustion control system of brown coal unit provided by the invention;
Fig. 5 is the schematic diagram of the combustion control system of flue gas conditioning device provided by the invention;
Fig. 6 is the schematic diagram of the combustion control system of conditioner provided by the invention;
The flow chart of the method for controlling combustion of Fig. 7 brown coal unit provided by the invention.
The specific embodiment
Below in conjunction with the accompanying drawing in the embodiment of the present invention, the technical scheme in the embodiment of the present invention is clearly and completely described, obviously, described embodiment is only the present invention's part embodiment, rather than whole embodiment.Based on the embodiment in the present invention, those of ordinary skills belong to the scope of protection of the invention not making the every other embodiment that obtains under the creative work prerequisite.
Fig. 2 is the schematic diagram of the combustion control system of brown coal unit provided by the invention.Described system comprises: boiler 205, coal pulverizer 204, air preheater 206, dust removal machine 207, air-introduced machine 201, primary air fan 203, overfire air fan 202 and chimney 208; Wherein, coal pulverizer 204 is connected between boiler 205 primary air fan 203 outlets, overfire air fan 202 outlets connect and boiler 205, realize the air preheat between flue, Secondary Air pipeline, wind pipeline in air preheater 206, deduster 207 is connected between the flue and air-introduced machine 201 entrances of air preheater, and the outlet of air-introduced machine is connected with chimney 208.
Described system also comprises: flue gas conditioning device 209;
Described flue gas conditioning device 209 is connected between described air-introduced machine 201 outlets and described primary air fan 203 entrances by flue, and the flue gas that air-introduced machine 201 is sent feeds back to described primary air fan 203 entrances;
Described primary air fan 203 mixes the flue gas of feedback with the air sent into of outside, and mist is sent into 205 pairs of brown coal of described boiler by described air preheater 206 and coal pulverizer 204 burns.
In the present embodiment, because the flue gas from the air-introduced machine feedback has certain heat, being mixed to get mist by the air of sending in the outside from the flue gas of air-introduced machine feedback.With respect to only using air as drier in prior art, this example as drier, can utilize the heat of low-temperature flue gas to carry out drying to brown coal described mist, reduces the use amount of air.
In the present embodiment, by air preheater 206, the fin with the flue gas in boiler back end ductwork by inside will enter air preheat before boiler to uniform temperature, help full combustion of fuel and improve the heat exchange performance of boiler, reduce energy consumption.For energy-conservation, air preheat has great importance.
In the present embodiment, coal pulverizer 204 grinds described fuel and obtains coal dust, and it is in order to increase the surface area of fuel, to be used for more fully burning that fuel is ground to form coal dust.
Overfire air fan 202 entrance suction be air, to input Secondary Air be for coal dust is burnt more fully again through mixing once air-dry dry coal dust later.
In the present embodiment, described flue gas conditioning device 209 is adjustable plate, and this adjustable plate is regulated and entered ducted flue gas, that is to say, can regulate the shared ratio of flue gas in described mist by this adjustable plate.Particularly, this adjustable plate can be for manually adjusting plate.This adjustable plate can also be regulated by PI (proportional integral) adjuster or PID (proportional integral feedforward) adjuster.For the those skilled in the art, under grasping under the prerequisite of the technology of technical field, common variation, the change that this adjustable plate is carried out or replace all should be included in protection scope of the present invention within.
Beneficial effect of the present invention is, be connected between described air-introduced machine outlet and described primary air fan entrance by flue by flue gas conditioning device, mix a certain amount of flue gas in a wind, not only can reduce the use amount of a wind of boiler, and can be with NO
xWithin being controlled at acceptability limit, simultaneously due to the steam air heater of having cancelled a wind, reduce the resistance of a wind pipeline, reduced the power consumption of primary air fan.
Embodiment two:
Fig. 3 is the schematic diagram of the combustion control system of brown coal unit provided by the invention.Described system comprises: boiler 305, coal pulverizer 304, air preheater 306, dust removal machine 307, air-introduced machine 301, primary air fan 303, overfire air fan 302 and chimney 308; Wherein, coal pulverizer 304 is connected between boiler 305 primary air fan 303 outlets, overfire air fan 302 outlets connect and boiler 305, realize the air preheat between flue, Secondary Air pipeline, wind pipeline in air preheater 306, deduster 307 is connected between the flue and air-introduced machine 301 entrances of air preheater, and the outlet of air-introduced machine is connected with chimney 308.
Described system also comprises: flue gas conditioning device 309;
Described flue gas conditioning device 309 is connected between described air-introduced machine 301 outlets and described primary air fan 303 entrances by flue, and the flue gas that air-introduced machine 301 is sent feeds back to described primary air fan 303 entrances;
Described primary air fan 303 mixes the flue gas of feedback with the air sent into of outside, and mist is sent into 305 pairs of brown coal of described boiler by described air preheater 306 and coal pulverizer 304 burns.
In the present embodiment, because the flue gas from air-introduced machine 301 feedbacks has certain heat, being mixed to get mist by the air of sending in the outside from the flue gas of air-introduced machine 301 feedbacks.With respect to only using air as drier in prior art, this example as drier, can utilize the heat of low-temperature flue gas to carry out drying to brown coal described mist, reduces the use amount of air.
In the present embodiment, by air preheater 306, the fin with the flue gas in boiler back end ductwork by inside will enter air preheat before boiler to uniform temperature, help full combustion of fuel and improve the heat exchange performance of boiler, reduce energy consumption.For energy-conservation, air preheat has great importance.
In the present embodiment, coal pulverizer 304 grinds described fuel and obtains coal dust, and it is in order to increase the surface area of fuel, to be used for more fully burning that fuel is ground to form coal dust.
Overfire air fan 302 entrance suction be air, to input Secondary Air be for coal dust is burnt more fully again through mixing once air-dry dry coal dust later.
In the present embodiment, described flue gas conditioning device 309 is adjustable plate, and this adjustable plate is regulated and entered ducted flue gas, that is to say, can regulate the shared ratio of flue gas in described mist by this adjustable plate.Particularly, this adjustable plate can be for manually adjusting plate.For the those skilled in the art, under grasping under the prerequisite of the technology of technical field, common variation, the change that this adjustable plate is carried out or replace all should be included in protection scope of the present invention within.
Described system also comprises: oxygen sensor 310 is installed between described primary air fan 303 outlets and air preheater 307, and is electrically connected to described flue gas conditioning device 309.Preferably, oxygen sensor 310 also can be connected to distribution control system (Distributed Control System, DCS) in, be used for the total amount of the mixture of a wind air/smoke of control, the ratio of air, flue gas is regulated by the gas baffle that installs additional.
Preferably, as shown in Figure 4, described flue gas conditioning device 309 comprises: adjustable plate 3091 and adjustable plate controller 3092, described controller 3092 is electrically connected to described sensor 310, receives the oxygen content signal of described oxygen sensor detection and according to described oxygen content signal, described adjustable plate 3091 is controlled.Described adjustable plate controller 3092 can be adjuster or PID (proportional integral feedforward) adjuster.In actual applications, when supposing oxygen content lower than a certain setting value, open large baffle plate, if instead the oxygen amount in air quantity is worth higher than this, close small front apron.For the those skilled in the art, under grasping under the prerequisite of the technology of technical field, common variation, the change that flue gas conditioning device 309 is carried out or replace all should be included in protection scope of the present invention within.
Beneficial effect of the present invention is, be connected between described air-introduced machine outlet and described primary air fan entrance by flue by flue gas conditioning device, mix a certain amount of flue gas in a wind, not only can reduce the use amount of a wind of boiler, and can be with NO
xWithin being controlled at acceptability limit, simultaneously due to the steam air heater of having cancelled a wind, reduce the resistance of a wind pipeline, reduced the power consumption of primary air fan.
Embodiment three:
Fig. 5 is the schematic diagram of the combustion control system of brown coal unit provided by the invention.Described system comprises: boiler 505, coal pulverizer 504, air preheater 506, dust removal machine 507, air-introduced machine 501, primary air fan 503, overfire air fan 502 and chimney 508; Wherein, coal pulverizer 504 is connected between boiler 505 primary air fan 503 outlets, overfire air fan 502 outlets connect and boiler 505, realize the air preheat between flue, Secondary Air pipeline, wind pipeline in air preheater 506, deduster 507 is connected between the flue and air-introduced machine 501 entrances of air preheater, and the outlet of air-introduced machine is connected with chimney 508.
Described system also comprises: flue gas conditioning device 509;
Described flue gas conditioning device 509 is connected between described air-introduced machine 501 outlets and described primary air fan 503 entrances by flue, and the flue gas that air-introduced machine 501 is sent feeds back to described primary air fan 503 entrances;
Described primary air fan 503 mixes the flue gas of feedback with the air sent into of outside, and mist is sent into 505 pairs of brown coal of described boiler by described air preheater 506 and coal pulverizer 504 burns.
In the present embodiment, because the flue gas from air-introduced machine 501 feedbacks has certain heat, being mixed to get mist by the air of sending in the outside from the flue gas of air-introduced machine 501 feedbacks.With respect to only using air as drier in prior art, this example as drier, can utilize the heat of low-temperature flue gas to carry out drying to brown coal described mist, reduces the use amount of air.
In the present embodiment, by air preheater 506, the fin with the flue gas in boiler back end ductwork by inside will enter air preheat before boiler to uniform temperature, help full combustion of fuel and improve the heat exchange performance of boiler, reduce energy consumption.For energy-conservation, air preheat has great importance.
In the present embodiment, coal pulverizer 504 grinds described fuel and obtains coal dust, and it is in order to increase the surface area of fuel, to be used for more fully burning that fuel is ground to form coal dust.
Overfire air fan 502 entrance suction be air, to input Secondary Air be for coal dust is burnt more fully again through mixing once air-dry dry coal dust later.
In the present embodiment, described flue gas conditioning device 509 is adjustable plate, and this adjustable plate is regulated and entered ducted flue gas, that is to say, can regulate the shared ratio of flue gas in described mist by this adjustable plate.Particularly, this adjustable plate can be for manually adjusting plate.For the those skilled in the art, under grasping under the prerequisite of the technology of technical field, common variation, the change that this adjustable plate is carried out or replace all should be included in protection scope of the present invention within.
Described system also comprises: oxygen sensor 510 is installed between described primary air fan 503 outlets and air preheater 507, and is electrically connected to described flue gas conditioning device 509.Preferably, oxygen sensor 510 also can be connected to distribution control system (Distributed Control System, DCS) in, be used for the total amount of the mixture of a wind air/smoke of control, the ratio of air, flue gas is regulated by the gas baffle that installs additional.
Preferably, as shown in Figure 4, described flue gas conditioning device 309 comprises: adjustable plate 3091 and adjustable plate controller 3092, described controller 3092 is electrically connected to described sensor 310, receives the oxygen content signal of described oxygen sensor detection and according to described oxygen content signal, described adjustable plate 3091 is controlled.Described adjustable plate controller 3092 can be adjuster or PID (proportional integral feedforward) adjuster.In actual applications, when supposing oxygen content lower than a certain setting value, open large baffle plate, if instead the oxygen amount in air quantity is worth higher than this, close small front apron.For the those skilled in the art, under grasping under the prerequisite of the technology of technical field, common variation, the change that flue gas conditioning device 309 is carried out or replace all should be included in protection scope of the present invention within.
Described system also comprises: conditioner 511;
Described conditioner 511 is connected in described primary air fan 503 entrances by flue, the outside is sent into the air capacity of described primary air fan 503 and is regulated.
Preferably, as shown in Figure 6, described conditioner 511 comprises: adjustable plate 5111 and adjustable plate controller 5112, described adjustable plate controller 5112 is electrically connected to described sensor 503, receives the oxygen content signal of described oxygen sensor 503 detections and according to described oxygen content signal, described adjustable plate 5111 is controlled.
Particularly, the requirement of a wind total amount determines by brown coal moisture, and the brown coal take total moisture as 40% are as example, if adopt pure air dry, need 50% primary air ratio, namely dry 1t coal approximately needs 3～4t air, and the coal pulverizer outlet temperature can only arrive 60 ℃ of left and right.Adopt the air/smoke mixture dry, because flue gas specific heat is larger, the total amount that reaches the uniform temp needs is smaller, but because the amount of oxygen in flue gas reduces, coal pulverizer requirement of explosion proof, outlet temperature can be brought up to 70～80 ℃.
Below specifically introduce controlling primary air ratio:
1) the total exhaust gas volumn that exports according to primary air fan/air capacity total amount and primary air fan outlet oxygen amount obtain a wind air capacity:
In formula:
M
PrABe the air capacity in primary air fan outlet cigarette/empty mixture;
M
A﹠amp; GBe primary air fan outlet cigarette/empty amount of the mixture;
O
2, prABe the oxygen volume ratio in primary air fan outlet cigarette/empty mixture.
2) condition of based on fuel is determined the flow of the mixture of primary air and flue gas:
In formula:
Max is large for getting;
M
CoalBe the quality of fuel flow, get the coal-supplying amount output of feeder;
K is that coal-air ratio is controlled parameter, i.e. the mass flow of a wind air/smoke mixture and the ratio of coal-supplying amount, it is directly proportional to fuel quantity, roughly the coal pulverizer outlet temperature is controlled at 60～80 ℃ want scope within;
M
minMinimum air quantity for coal pulverizer can bear is determined by coal pulverizer itself.
3) adjusting of baffle plate is used for the ratio between wind problem of control and exhaust gas volumn, suppose that it was 12% (in the wind total amount of this moment, the ratio of flue gas and air is about 1: 1), if air quantity oxygen amount is worth lower than this, open large baffle plate, if instead the oxygen amount in air quantity is worth higher than this, close small front apron.An available PI or PID adjuster are regulated.
4) temperature that exports by coal pulverizer is accurately controlled the total amount of a wind and smoke mixture, first calculate the total amount of a minimum wind and smoke mixture by condition (2), carry out as fundamental line the initial value that PI regulates, if outlet temperature is low, the total amount of the total wind and smoke mixture of XXL, otherwise, reduce the total amount of a wind and smoke mixture; If below minimum air quantity, the coal pulverizer outlet temperature is also high, reduces and extracts exhaust gas volumn, no matter oxygen amount definite value.
Can fall the total amount of oxygen in wind get off by aforesaid operations, realized high moisture content brown coal fuel dry with burning, reduce NO
xTriple requirements.Cancel simultaneously wind temperature adjustment wind art designs at present commonly used, make an all wind all the time through the air preheater heat absorption, guaranteed boiler efficiency.
Beneficial effect of the present invention is, be connected between described air-introduced machine outlet and described primary air fan entrance by flue by flue gas conditioning device, mix a certain amount of flue gas in a wind, not only can reduce the use amount of a wind of boiler, and can be with NO
xWithin being controlled at acceptability limit, simultaneously due to the steam air heater of having cancelled a wind, reduce the resistance of a wind pipeline, reduced the power consumption of primary air fan.
Embodiment four:
The schematic diagram of the method for controlling combustion of Fig. 7 brown coal unit provided by the invention.Described method comprises:
S701: the flue gas that the air-introduced machine outlet is sent feeds back to the primary air fan entrance;
S702: described primary air fan mixes the flue gas of feedback with the air sent into of outside, and mist is sent into described boiler by air preheater and coal pulverizer brown coal are burnt.
In order to set forth in more detail the method that the embodiment of the present invention provides.Please refer to the combustion control system of the brown coal unit that Fig. 5 provides herein.In the present embodiment, because the flue gas from air-introduced machine 501 feedbacks has certain heat, being mixed to get mist by the air of sending in the outside from the flue gas of air-introduced machine 501 feedbacks.With respect to only using air as drier in prior art, this example as drier, can utilize the heat of low-temperature flue gas to carry out drying to brown coal described mist, reduces the use amount of air.
In the present embodiment, described method also comprises: the oxygen content of the described mist that primary air fan is sent checks, and according to described oxygen content, the exhaust gas volumn that feeds back to the primary air fan entrance is regulated.
In the present embodiment, described method also comprises: the oxygen content of the described mist that primary air fan is sent checks, and according to described oxygen content, the air capacity that feeds back to the primary air fan entrance is regulated.
Described method also comprises: obtain the mist total amount of described primary air fan outlet, according to the ratio of described oxygen content and mist, the exhaust gas volumn that feeds back to the primary air fan entrance is regulated.
Described method also comprises: obtain the air content in the mist of described primary air fan outlet, according to described air content, the air capacity that feeds back to the primary air fan entrance is regulated.
Below specifically introduce controlling primary air ratio:
1) the total exhaust gas volumn that exports according to primary air fan/air capacity total amount and primary air fan outlet oxygen amount obtain a wind air capacity:
In formula:
M
PrABe the air capacity in primary air fan outlet cigarette/empty mixture;
M
A﹠amp; GBe primary air fan outlet cigarette/empty amount of the mixture;
O
2, prABe the oxygen volume ratio in primary air fan outlet cigarette/empty mixture.
2) condition of based on fuel is determined the flow of the mixture of primary air and flue gas:
In formula:
Max is large for getting;
M
CoalBe the quality of fuel flow, get the coal-supplying amount output of feeder;
K is that coal-air ratio is controlled parameter, i.e. the mass flow of a wind air/smoke mixture and the ratio of coal-supplying amount, it is directly proportional to fuel quantity, roughly the coal pulverizer outlet temperature is controlled at 60～80 ℃ want scope within;
M
minMinimum air quantity for coal pulverizer can bear is determined by coal pulverizer itself.
3) adjusting of baffle plate is used for the ratio between wind problem of control and exhaust gas volumn, suppose that it was 12% (in the wind total amount of this moment, the ratio of flue gas and air is about 1: 1), if air quantity oxygen amount is worth lower than this, open large baffle plate, if instead the oxygen amount in air quantity is worth higher than this, close small front apron.An available PI or PID adjuster are regulated.
4) temperature that exports by coal pulverizer is accurately controlled the total amount of a wind and smoke mixture, first calculate the total amount of a minimum wind and smoke mixture by condition (2), carry out as fundamental line the initial value that PI regulates, if outlet temperature is low, the total amount of the total wind and smoke mixture of XXL, otherwise, reduce the total amount of a wind and smoke mixture; If below minimum air quantity, the coal pulverizer outlet temperature is also high, reduces and extracts exhaust gas volumn, no matter oxygen amount definite value.
Beneficial effect of the present invention is, be connected between described air-introduced machine outlet and described primary air fan entrance by flue by flue gas conditioning device, mix a certain amount of flue gas in a wind, not only can reduce the use amount of a wind of boiler, and can be with NO
xWithin being controlled at acceptability limit, simultaneously due to the steam air heater of having cancelled a wind, reduce the resistance of a wind pipeline, reduced the power consumption of primary air fan.
It will be appreciated by those skilled in the art that accompanying drawing is the schematic diagram of a preferred embodiment, the unit in accompanying drawing or flow process might not be that enforcement the present invention is necessary.The invention described above embodiment sequence number does not represent the quality of embodiment just to description.
Above embodiment is the preferred embodiments of the disclosure, within the common variation that the those skilled in the art carries out in the technical scheme of the embodiment of the present invention, change or replacement all should be included in protection scope of the present invention.
Claims (12)
1. the method for controlling combustion of a brown coal unit, is characterized in that, described method comprises:
The flue gas that the air-introduced machine outlet is sent feeds back to the primary air fan entrance;
Described primary air fan mixes the flue gas of feedback with the air sent into of outside, and mist is sent into boiler by air preheater and coal pulverizer brown coal are burnt;
Described method also comprises:
Obtain primary air fan according to the total amount of primary air fan outlet flue gas/air mixture and oxygen content in primary air fan outlet flue gas/air mixture and export air capacity in flue gas/air mixture:
In formula:
M
PrABe the air capacity in primary air fan outlet flue gas/air mixture;
M
A﹠amp; GTotal amount for primary air fan outlet flue gas/air mixture;
O
2, prABe the oxygen content in primary air fan outlet flue gas/air mixture;
The condition of based on fuel is determined the total amount of primary air fan outlet flue gas/air mixture:
In formula:
Max is for getting large value;
M
CoalBe the quality of fuel flow, get the coal-supplying amount output quantity of feeder;
K is that coal-air ratio is controlled parameter, gets the mass flow and the ratio of coal-supplying amount of primary air fan outlet flue gas/air mixture, within the coal pulverizer outlet temperature being controlled at the scope of 60～80 ℃;
M
minThe minimum air quantity that can bear for coal pulverizer;
Control by the temperature that coal pulverizer exports the total amount that primary air fan exports flue gas/air mixture, first calculate the total amount of minimum primary air fan outlet flue gas/air mixture by above-mentioned formula (2), carry out as fundamental line the initial value that PI regulates, if outlet temperature is low, strengthen the total amount of primary air fan outlet flue gas/air mixture, otherwise, reduce the total amount that primary air fan exports flue gas/air mixture.
2. the method for claim 1, is characterized in that, the oxygen content of the described mist that primary air fan is sent checks, and according to described oxygen content, the exhaust gas volumn that feeds back to the primary air fan entrance regulated.
3. the method for claim 1, is characterized in that, the oxygen content of the described mist that primary air fan is sent checks, and according to described oxygen content, the air capacity that feeds back to the primary air fan entrance regulated.
4. method as claimed in claim 2, is characterized in that, obtains the mist total amount of described primary air fan outlet, according to the ratio of described oxygen content and mist, the exhaust gas volumn that feeds back to the primary air fan entrance regulated.
5. the method for claim 1, is characterized in that, obtains the air content in the mist of described primary air fan outlet, according to described air content, the air capacity that feeds back to the primary air fan entrance regulated.
6. the combustion control system of a brown coal unit is used the method for controlling combustion of brown coal unit as claimed in claim 1, and described system comprises: boiler, coal pulverizer, air preheater, dust removal machine, air-introduced machine, primary air fan, overfire air fan and chimney; It is characterized in that, described system also comprises: flue gas conditioning device;
Described flue gas conditioning device is connected between described air-introduced machine outlet and described primary air fan entrance by flue, and the flue gas that air-introduced machine is sent feeds back to described primary air fan entrance;
Described primary air fan mixes the flue gas of feedback with the air sent into of outside, and mist is sent into described boiler by described air preheater and coal pulverizer brown coal are burnt;
Wherein: obtain primary air fan according to the total amount of primary air fan outlet flue gas/air mixture and oxygen content in primary air fan outlet flue gas/air mixture and export air capacity in flue gas/air mixture:
In formula:
M
PrABe the air capacity in primary air fan outlet flue gas/air mixture;
M
A﹠amp; GTotal amount for primary air fan outlet flue gas/air mixture;
O
2, prABe the oxygen content in primary air fan outlet flue gas/air mixture;
The condition of based on fuel is determined the total amount of primary air fan outlet flue gas/air mixture:
In formula:
Max is for getting large value;
M
CoalBe the quality of fuel flow, get the coal-supplying amount output quantity of feeder;
K is that coal-air ratio is controlled parameter, gets the mass flow of a wind air/smoke mixture and the ratio of coal-supplying amount, within the coal pulverizer outlet temperature being controlled at the scope of 60～80 ℃;
M
minThe minimum air quantity that can bear for coal pulverizer;
Control by the temperature that coal pulverizer exports the total amount that primary air fan exports flue gas/air mixture, first calculate the total amount of minimum primary air fan outlet flue gas/air mixture by above-mentioned formula (2), carry out as fundamental line the initial value that PI regulates, if outlet temperature is low, strengthen the total amount of primary air fan outlet flue gas/air mixture, otherwise, reduce the total amount that primary air fan exports flue gas/air mixture.
7. combustion control system as claimed in claim 6, is characterized in that, described flue gas conditioning device comprises: adjustable plate.
8. combustion control system as claimed in claim 6, is characterized in that, described system also comprises: oxygen sensor is installed between described primary air fan outlet and air preheater, and is electrically connected to described flue gas conditioning device.
9. combustion control system as claimed in claim 8, it is characterized in that, described flue gas conditioning device comprises: adjustable plate and adjustable plate controller, described controller is connected with described sensor electrical, receives the oxygen content signal of described oxygen sensor detection and according to described oxygen content signal, described adjustable plate is controlled.
10. combustion control system as claimed in claim 6, is characterized in that, described system also comprises: conditioner;
Described conditioner is connected in described primary air fan entrance by flue, the outside is sent into the air capacity of described primary air fan and is regulated.
11. combustion control system as claimed in claim 10 is characterized in that, described system also comprises: oxygen sensor is installed between described primary air fan outlet and air preheater, and is electrically connected to described conditioner.
12. combustion control system as claimed in claim 11, it is characterized in that, described conditioner comprises: adjustable plate and adjustable plate controller, described controller is connected with described sensor electrical, receives the oxygen content signal of described oxygen sensor detection and according to described oxygen content signal, described adjustable plate is controlled.
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| CN102721068B (en) * | 2012-07-11 | 2016-06-08 | 光大环保科技发展（北京）有限公司 | A kind of control method of water-cooled reciprocating-type multi-stage hydraulic mechanical grate furnace air feed system |
| CN103292342B (en) * | 2013-05-31 | 2016-03-09 | 大唐甘谷发电厂 | A kind of bituminous coal fired boiler that uses mixes the method for burning Xinjiang Guang Hui brown coal |
| CN105042630B (en) * | 2015-07-27 | 2017-10-17 | 中国神华能源股份有限公司 | Oxygen-enriched combustion system oxygen supply control device and method |
| CN106391284B (en) * | 2016-08-31 | 2019-10-18 | 珠海市华远自动化科技有限公司 | A kind of system and control method adjusting coal pulverizer internal oxygen concentration |
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