CN105783025B - A method of wind powder distribution in the low NOx tangential firing boilers stove of monitoring - Google Patents
A method of wind powder distribution in the low NOx tangential firing boilers stove of monitoring Download PDFInfo
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- 238000000034 method Methods 0.000 title claims abstract description 32
- 239000000843 powder Substances 0.000 title claims abstract description 31
- 238000012544 monitoring process Methods 0.000 title claims abstract description 17
- 238000010304 firing Methods 0.000 title claims abstract description 16
- 239000003245 coal Substances 0.000 claims abstract description 162
- 238000002485 combustion reaction Methods 0.000 claims abstract description 52
- 238000002474 experimental method Methods 0.000 claims abstract description 7
- 238000000926 separation method Methods 0.000 claims description 7
- 239000002817 coal dust Substances 0.000 claims description 6
- 230000001186 cumulative effect Effects 0.000 claims description 6
- 238000000205 computational method Methods 0.000 claims description 5
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims description 3
- 229910052799 carbon Inorganic materials 0.000 claims description 3
- 238000002347 injection Methods 0.000 claims description 2
- 239000007924 injection Substances 0.000 claims description 2
- 235000002918 Fraxinus excelsior Nutrition 0.000 claims 1
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- 230000000694 effects Effects 0.000 abstract description 2
- MWUXSHHQAYIFBG-UHFFFAOYSA-N nitrogen oxide Inorganic materials O=[N] MWUXSHHQAYIFBG-UHFFFAOYSA-N 0.000 description 69
- 238000005516 engineering process Methods 0.000 description 12
- 238000001816 cooling Methods 0.000 description 7
- 238000012360 testing method Methods 0.000 description 7
- 239000002245 particle Substances 0.000 description 5
- 239000000446 fuel Substances 0.000 description 4
- 238000010438 heat treatment Methods 0.000 description 4
- 239000007921 spray Substances 0.000 description 4
- 230000001464 adherent effect Effects 0.000 description 3
- 238000004364 calculation method Methods 0.000 description 3
- 238000010586 diagram Methods 0.000 description 3
- 239000007789 gas Substances 0.000 description 3
- 239000000203 mixture Substances 0.000 description 3
- 230000009466 transformation Effects 0.000 description 3
- UGFAIRIUMAVXCW-UHFFFAOYSA-N Carbon monoxide Chemical compound [O+]#[C-] UGFAIRIUMAVXCW-UHFFFAOYSA-N 0.000 description 2
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 2
- 210000000038 chest Anatomy 0.000 description 2
- 238000013461 design Methods 0.000 description 2
- 239000000428 dust Substances 0.000 description 2
- 239000004744 fabric Substances 0.000 description 2
- 239000003546 flue gas Substances 0.000 description 2
- 239000001301 oxygen Substances 0.000 description 2
- 229910052760 oxygen Inorganic materials 0.000 description 2
- 238000002360 preparation method Methods 0.000 description 2
- 238000003672 processing method Methods 0.000 description 2
- 239000000126 substance Substances 0.000 description 2
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 2
- 201000004569 Blindness Diseases 0.000 description 1
- OAICVXFJPJFONN-UHFFFAOYSA-N Phosphorus Chemical compound [P] OAICVXFJPJFONN-UHFFFAOYSA-N 0.000 description 1
- 230000002159 abnormal effect Effects 0.000 description 1
- 230000009471 action Effects 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 230000005540 biological transmission Effects 0.000 description 1
- 238000006555 catalytic reaction Methods 0.000 description 1
- 238000010531 catalytic reduction reaction Methods 0.000 description 1
- 230000004069 differentiation Effects 0.000 description 1
- 238000009510 drug design Methods 0.000 description 1
- 230000005611 electricity Effects 0.000 description 1
- 230000007613 environmental effect Effects 0.000 description 1
- 239000003500 flue dust Substances 0.000 description 1
- 230000004907 flux Effects 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- RJMUSRYZPJIFPJ-UHFFFAOYSA-N niclosamide Chemical compound OC1=CC=C(Cl)C=C1C(=O)NC1=CC=C([N+]([O-])=O)C=C1Cl RJMUSRYZPJIFPJ-UHFFFAOYSA-N 0.000 description 1
- 229910052698 phosphorus Inorganic materials 0.000 description 1
- 239000011574 phosphorus Substances 0.000 description 1
- 238000012545 processing Methods 0.000 description 1
- 230000009467 reduction Effects 0.000 description 1
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- 239000000243 solution Substances 0.000 description 1
Classifications
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
- F23N—REGULATING OR CONTROLLING COMBUSTION
- F23N1/00—Regulating fuel supply
- F23N1/02—Regulating fuel supply conjointly with air supply
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- Combustion & Propulsion (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Regulation And Control Of Combustion (AREA)
Abstract
The invention discloses the methods of wind powder distribution in a kind of low NOx tangential firing boilers stove of monitoring, including：Under the cold condition that boiler is not lighted a fire, drag characteristic experiment is carried out to secondary air damper, obtains the drag characteristic of baffle and burner hearth；The wind speed of overfire air jet when boiler thermal-state operation is calculated according to above-mentioned drag characteristic；The excess air coefficient for calculating different burning blocks in stove, obtains wind powder distribution in stove.Advantageous effect of the present invention：The information that each combustion zone excess air coefficient in stove can be provided to operations staff enables them to the air classification intensity for determining main burning area, especially suitable for the low NOx tangential firing boilers using unit pulverized-coal system.
Description
Technical field
The present invention relates to wind powder distribution monitoring technical field in stove more particularly to a kind of low NOx tangential firing boilers of monitoring
The method that wind powder is distributed in stove.
Background technology
With the raising of environmental requirement, the control that nitrogen oxides (NOx) is discharged in thermal power plant is increasingly stringenter；In stove
Low NOx combusting technology NOx control techniques after burning are combined, and are to remove most effective, the most economical side of nitrogen oxides in effluent
Formula；In recent years, boiler of power plant has carried out large-scale low NOx combusting technology transformation, and is mounted with to select in boiler back end ductwork
Property catalysis reduction (SCR：Selective Catalytic Reduction) equipment carrys out the nitrogen oxides in cooperation-removal flue gas,
Currently, this denitrogenation mode successfully controls nitrogen oxides from coal-fired boiler (NOx) discharge capacity in 50mg/m3Below.
As low-NOx coal powder technology is largely applied, influence of the technology to Boiler Operation and operating parameter
It becomes increasingly conspicuous.The core scheme of low NOx combusting technology is to separate out a part of combustion air from main burning differentiation, by these skies
Burnout degree nozzle of the gas at top is sent into burner hearth, realizes the Researched of Air Staging Combustion Burning Pulverized Coal of coal dust；Air classification changes coal dust in stove
Combustion distribution, thus fire box temperature field and exit gas temperature are changed, stove internal heating surface caloric receptivity and pulverized coal particle after-flame degree
Also it changes therewith；Some boilers are after completing low NOx combusting technology transformation, since furnace air is classified unreasonable, flying dust
Phosphorus content increases, and vapor (steam) temperature significantly reduces, it is difficult to reach design value；And after some boiler improvements, vapor (steam) temperature increases, desuperheat
Water increases；Since the caloric receptivity of reheating vapour system was much smaller than hot vapour system, shadow of the low NOx combusting technology to reheat steam temperature degree
Sound compared hot vapour bigger, and therefore, for being equipped with the boiler of radiant reheater in stove, low NOx combusting technology is to vapor (steam) temperature
It influences more prominent.
In design, the air capacity that low-NOx coal powder technology supplies main burning area is controlled in theoretical air requirement
75% or so, that is, it is about 0.75 to keep main burning area excess air coefficient, is in anaerobic condition；Therefore, comprising big in the region
Amount, temperature is very high but the uncombusted pulverized coal particle that stays cool of burning, these particles once obtain oxygen, can be quickly
Heat is released, this feature has decisive action to the operation characteristic of low NOx combusting technology：Bellows-burner hearth differential pressure fluctuation is to main combustion
Burning area's particle after-flame degree, which will produce, to be significantly affected, and the fluctuation of bellows-burner hearth differential pressure means the wave of main burning area supply air capacity
It is dynamic, the regions particulate after-flame degree can be caused and release the fluctuation of heat, stove internal heating surface caloric receptivity also fluctuates therewith；This is special
Practical manifestation of the property in boiler operatiopn is that after being transformed into low NOx combustion system, the fluctuating range of boiler steam temperature is apparent
Increase；This is determined in the severe depletion of oxygen of main burning area, to the fluctuation more sensitivity of bellows-burner hearth differential pressure by low NOx combusting technology
Fixed.
The fluctuation of Lu Nei main burnings area air supply amount can not only cause steam temperature to fluctuate, and control of steam temperature difficulty is made to increase, and
And foregoing unburned carbon in flue dust increases, steam owes temperature or spray water flux is excessive, is also due to point of furnace air and coal dust
Cloth does not reach caused by rational design requirement.It is, in general, that Lu Nei main burnings area wind coal proportion is too small, flying dust can be caused
Combustible increases, and steam temperature increases；Wind coal proportion is excessive, and NOx discharge can be caused exceeded, and steam temperature reduces；Therefore, for low NOx
Pulverized coal combustion system, it is vital that the distribution of wind powder, which is the monitoring of each combustion zone excess air, in stove, it is to ensure low NOx
Combustion system reasonably carries out the effective means of air classification, and optimizing to boiler operatiopn and controlling has more important meaning.
Currently, for the tangentially fired boiler using unit pulverized-coal system, the monitoring and adjusting of coal nozzle powder supply amount
It is to be contributed by feeder；And air nozzle is large number of, measuring condition is severe, these nozzles supply air capacity simply by
Baffle is adjusted, and there are no the measurements realized to air mass flow, and therefore, it is superfluous that operations staff can not obtain each combustion zone in stove
The information of air coefficient；In actual operation, boiler load and coal powder distribation state are changeable, and operations staff is to air nozzle flow
Adjustment there is very big blindness, this is some low-NOx coal powder systems is drawn due to using unreasonable air classification intensity
Play the main reason for boiler operating parameter is abnormal.
Invention content
The purpose of the present invention is exactly to provide a kind of monitor in low NOx tangential firing boilers stove to solve above-mentioned problem
The method of wind powder distribution, this method can provide the information of each combustion zone excess air coefficient in stove to operations staff, make them
The air classification intensity that can determine main burning area, especially suitable for the tangential coal-fired pots of the low NOx using unit pulverized-coal system
Stove.
To achieve the above object, concrete scheme of the invention is as follows：
A method of wind powder distribution in the low NOx tangential firing boilers stove of monitoring, including：
(1) under the non-ignition condition of boiler cold-state, drag characteristic experiment is carried out to secondary air damper, obtains secondary air damper
With the resistance coefficient of burner hearth；
Secondary air box-furnace outlet differential pressure for being monitored when being run according to resistance coefficient obtained above and boiler thermal-state,
Secondary Air pressure and temperature parameter calculate the wind speed of overfire air jet when hot operation；
(2) the Secondary Air pressure and temperature when operation of acquisition boiler thermal-state, calculates Secondary Air density；According to the Secondary Air
The area of density, the wind speed of overfire air jet and overfire air jet obtains the air mass flow of each overfire air jet；
(3) measure coal pulverizer give coal flow and air mass flow, be evenly distributed to described to coal flow and air mass flow
Each coal nozzle corresponding to the coal pulverizer；
(4) it is boundary with coal nozzle position, burner hearth is divided into several burning blocks；According to each overfire air jet and coal
Position of the powder nozzle in burner hearth, and the air mass flow and pulverized coal flow of these nozzles are flowed through, it calculates to enter in stove and respectively burn
The air mass flow and coal flow of section；
(5) it is taken into stove coal sample, according to the industrial components of as-fired coal sample, the burning of unit of account as-fired coal is required theoretical empty
Tolerance；
(6) it according to the calculated value of air mass flow and coal flow in burner hearth burning block, and is incorporated into needed for stove coal combustion
The theoretical air requirement wanted obtains the excess air coefficient of the burning block, it illustrates the wind powder distribution of the burner hearth burning block
State.
Further, the method for calculating Secondary Air density is specially in the step (2)：
According to the relational expression of the pressure of perfect gas, density and temperature, in conjunction with local atmospheric pressure, Secondary Air pressure and
Secondary Air temperature calculates Secondary Air density.
Further, the method for the air mass flow of calculating overfire air jet is in the step (2)：
The product of the wind speed of the air mass flow of overfire air jet and the area of the nozzle, Secondary Air density and the nozzle is at just
Than；According to Secondary Air density, the area of the wind speed of overfire air jet and overfire air jet, the air stream of overfire air jet is obtained
Amount.
Further, in the step (3), assigned by each coal nozzle is to coal flow：Coal pulverizer is given
The ratio of coal flow and the coal nozzle quantity corresponding to the coal pulverizer；
Air mass flow assigned by each coal nozzle is：Corresponding to the air mass flow of coal pulverizer and the coal pulverizer
The ratio of coal nozzle quantity.
Further, the main burning area for forming lower furnace portion coal nozzle and air nozzle in the step (4) and stove
The separation burnout degree combustion zone on thorax top is respectively as independent burning block.
Further, in the step (4), into stove in the computational methods of air mass flow of certain burning block be：To this
In combustion zone the air mass flow of the coal nozzles of all operation coal pulverizers cumulative and with all overfire air jets in the combustion zone
Air mass flow cumulative and summation；
The computational methods of the coal flow of certain burning block are in into stove：The coal stream of all operation coal pulverizers in the combustion zone
Amount cumulative and.
Further, in the step (6), the method for calculating the excess air coefficient of burning block is：
The sum of air mass flow into the burning block and the theoretical air requirement needed for the coal flow for entering the combustion zone
Ratio.
Beneficial effects of the present invention：
The method of the present invention can provide the wind powder distributed intelligence of each combustion zone in stove to operations staff, make operations staff at any time
Boiler wind speed adjustment is adjusted, achievees the purpose that rational air classification, meets the emission request of nitrogen oxides, meanwhile, it reduces
Influence of the low NOx combustion system to the other operating parameters of boiler.
Description of the drawings
Fig. 1 is burner hearth, heating surface, air nozzle, fuel nozzle, the secondary air damper of certain low NOx tangential firing boiler
The division of combustion zone in arrangement, burner nozzle area and stove；
Fig. 2 is the relation curve of the baffle resistance coefficient and aperture that are obtained according to secondary air damper attribute testing；
Fig. 3 is oven air flow rate and the column diagram to coal flow distribution；
Fig. 4 is variation of the excess air coefficient with furnace height.
Specific implementation mode：
The present invention is described in detail below in conjunction with the accompanying drawings：
The invention discloses the methods of wind powder distribution in a kind of low NOx tangential firing boilers burner hearth of monitoring, are in pot first
Under the cold condition that stove is not lighted a fire, drag characteristic experiment is carried out to secondary air damper, obtains the drag characteristic of baffle and burner hearth；So
The hot operation data for testing boiler afterwards calculates the excess air coefficient of different burning blocks in stove, obtains wind powder in stove and is distributed
State.
The method of the present invention specifically includes following steps：
(1) under the non-ignition condition of boiler cold-state, drag characteristic experiment is carried out to secondary air damper, obtains secondary air damper
With the resistance coefficient of burner hearth；Secondary air box-the burner hearth monitored when being run according to resistance coefficient obtained above and boiler thermal-state
Differential pressure, Secondary Air pressure and temperature parameter are exported, the wind speed of overfire air jet when hot operation is calculated；
Chinese patent may be used in the specific method of the step《The processing side of boiler secondary air baffle characteristics test data
Method》(application number：201510493413.2) the step of providing, handles test data, draws resistance coefficient-baffle and opens
The relation curve of degree obtains the resistance coefficient of burner hearth and each secondary air damper；And according to the resistance coefficient and hot fortune measured
The parameters such as collected bellows-burner hearth differential pressure, throttle opening and Secondary Air temperature when row calculate each under boiler actual motion state
The wind speed of a overfire air jet；
(2) Secondary Air pressure and temperature when being run according to boiler thermal-state calculates Secondary Air density；According to Secondary Air density,
Nozzle wind velocity and area obtain the air mass flow of each overfire air jet；
The specific method for calculating Secondary Air density and overfire air jet air mass flow is：
ρ2=0.003483 (p0+p)/(273.15+t2) (1)
ρ2For Secondary Air density (kg/m3), p0For local atmospheric pressure, (Pa), p is Secondary Air pressure, (Pa), t2It is two
Secondary air temperature, (DEG C).
For the air mass flow of i-th of overfire air jet, (t/h),For the area of the nozzle, (m2), ρ2It is close for Secondary Air
Degree, (kg/m3),Wind speed for i-th of the nozzle determined in step (1), (m/s).
(3) measure coal pulverizer give coal flow and air mass flow, these coal flows and air mass flow are evenly distributed to this
Coal nozzle corresponding to coal pulverizer；
The air mass flow and coal stream method for determination of amount of single coal nozzle corresponding to the coal pulverizer of operation be：
For the coal flow of single coal nozzle of jth platform coal pulverizer, (t/h),For jth platform Mo Mei Ji Give coal flows,
(t/h), n is the coal nozzle quantity corresponding to the coal pulverizer,For the air stream of the corresponding single coal nozzle of jth coal pulverizer
Amount, (t/h),For the air mass flow of jth coal pulverizer, (t/h).
(4) it is boundary with coal nozzle position, burner hearth is divided into several sections；According to each overfire air jet and pulverized coal injection
Position of the mouth in burner hearth, and the air and pulverized coal flow of these nozzles are flowed through, calculate the sky for entering each burning block in stove
Throughput and coal flow；
Combustion zone in low NOx tangential firing boilers stove be generally divided into lower furnace portion coal nozzle and air nozzle composition
Main burning area and combustion zone separation burnout degree (SOFA) of upper furnace, in operation, the two combustion zones should keep rational
Excess air coefficient realizes the Researched of Air Staging Combustion Burning Pulverized Coal of coal dust, with ensure lower NOx discharge, higher particle after-flame degree with
And good steam temperature control characteristic.
Main burning area excess air coefficient is the important symbol of low NOx combustion system air classification power, and operations staff is logical
Cross adjustment secondary air damper aperture or coal pulverizer give coal flow, main burning area excess air coefficient can be maintained reasonably
Data.Therefore, using main burning area and separation burnout degree area as individual section in the present invention.
The computational methods of air mass flow and coal flow into certain combustion zone are：
MFTo enter the sum of the coal flow of the combustion zone, (t/h), MATo enter the sum of the air mass flow of the burning block,
(t/h),Indicate that the air mass flow to the coal nozzle of all operation coal pulverizers in the combustion zone is summed,Expression pair
The air mass flow of all overfire air jets is summed in the combustion zone.
(5) it is taken into stove coal sample, the chemical examination of power transmission factory fuel laboratory obtains the industrial components of as-fired coal, calculates 1 kilogram accordingly
The required theoretical air requirement (kg/kg) of as-fired coal burning；
Under normal circumstances, the required theoretical air requirement of coal combustion is calculated according to the elemental composition of coal, currently, most electricity
Factory's coal laboratory can not carry out the test of coal elemental composition, and quickly to determine theoretical air requirement, the present invention provides according to coal
The method that industrial components calculate theoretical air capacity, specially：
m0For the required theoretical air requirement of as-fired coal burning, (kg/kg), FCadIt is fixed for the air-dried basis of as-fired coal
Carbon content (%), VadFor the air-dried basis volatile matter content of as-fired coal, (%), AadFor the air-dried basis ash content of as-fired coal
Content, (%), MarFor the moisture as received coal content of as-fired coal, (%).
(6) according to the calculated value of burner hearth burning block air mass flow and coal flow, and the theoretical air of coal combustion is combined
Amount, obtains the excess air coefficient of the section, it illustrates the wind powder distribution in region stove Nei.
The circular of certain combustion zone excess air coefficient is in stove：
α=MA/(MF×m0) (8)
α is the excess air coefficient of certain section in stove, (/).
Embodiment one：
Objective for implementation is a boiler of power plant, and Fig. 1 is the cloth of the boiler furnace, heating surface, air nozzle, fuel nozzle
Set, in area and stove combustion zone division；The boiler be one subcritical, single reheat, control loop drum boiler, single stove
The outdoor arrangement of thorax, inverted U, upper furnace are equipped with wall reheater, full large-size screen monitors and Late reworking；Boiler is direct-firing using positive pressure
Pulverized coal preparation system, be furnished with 5 RP923 medium-speed pulverizers, often cover pulverized coal preparation system to 4 burner powder supplies of same layer, therefore, formula (3) and
N=4 in formula (4), the stove are of five storeys coal nozzle altogether, are denoted as A, B, C, D, E successively from bottom to up, in wherein A layers of coal nozzle
It is also equipped with plasma igniter, air and fuel nozzle use quadrangle arranged tangential.
2013, low NOx combustion system transformation is completed, 4 layer separation burnout degree (Separated Overfire are increased
Air, abbreviation SOFA)) nozzle, totally 19 layers of improved air nozzle, 4 every layer, totally 76 air nozzles, this 19 layers of air spray
Mouth is respectively：1. 4SOFA nozzles, totally 4 layers, respectively SOFA1, SOFA2, SOFA3 and SOFA4；2. layer overfire air jet：Totally 4
Layer, is CD, DE and EE layers of Secondary Air and the compact burnout degrees of EE respectively；3. oil gun overfire air jet：Totally 2 layers, be AB, BC respectively
Layer oil gun Secondary Air；4. the surrounding air nozzle of coal nozzle：Totally 5 layers, be A surrounding airs, B surrounding airs, C surrounding airs, D circumferences respectively
Wind, E surrounding airs, 5. adherent wind nozzle：Totally 3 layers, be DE, EE and FF layers of adherent wind respectively；6. bottom AA Secondary Airs.These sprays
The area of mouth is shown in Fig. 1.
The flow of these Secondary Airs is by 15 secondary air damper xAA、xA、xAB、xB、xBC、xC、xCD、xD、xDE、xE、xEE、
xSOFA1、xSOFA2、xSOFA3、xSOFA4It controls, the arrangement of these baffles is shown in Fig. 1.Using coal nozzle as boundary, separation burnout degree and
Main burning area is divided into 7 burning blocks respectively as independent burning area, by burner hearth, sees Fig. 1, the excess air coefficient in each section
It is expressed as αA、αB、αC、αD、αE、αMZ、αSOFA, wherein αMZAnd αSOFAThe surplus in main burning area and burnout degree area is indicated respectively
Air coefficient.
Under the cold condition that boiler is not lighted a fire, drag characteristic experiment is carried out to secondary air damper, during experiment, is maintained
The pressure drop of secondary air box to furnace outlet is 500Pa, respectively in secondary air damper aperture 100%, 75%, 50%, 25%, 0%
When, measure the wind speed of 19 layers of overfire air jet of burner hearth quadrangle；Using Chinese patent《Boiler secondary air baffle characteristics test data
Processing method》(application number：201510493413.2) provide method and steps, obtain SOFA Secondary Airs, adherent and circumference
The resistance coefficient of the various air nozzles such as Secondary Air, AA layer Secondary Air, layer Secondary Air and oil gun Secondary Air is shown in Fig. 2, burner hearth
Resistance coefficient ζL=1.699.
In the case where unit load is certain operating status of 300MW, secondary air box-furnace outlet differential pressure Δ P=1001.3Pa, two
Secondary wind pressure p=971Pa, Secondary Air temperature t2=304.3 DEG C, secondary air damper aperture is shown in Table 1, and what is provided according to fig. 2 is secondary
Windshield plate drag-coefficient curve, the resistance coefficient for obtaining secondary air damper are shown in Table 1；Using Chinese patent《Boiler secondary windshield plate
The processing method of attribute testing data》(application number：201510493413.2) provide method and steps, obtain each two in Fig. 1
The wind speed of secondary wind air nozzle is shown in Table 1；To adjust reheat steam temperature degree or flue gas temperature of hearth outlet deviation, this arranged tangential
Air and coal nozzle generally can be upper and lower or swing, and therefore, there are gap, these gap structures between nozzle and bellows
The channel of burner hearth is flowed to from bellows at air, the flowing of these air objectively plays the cooling effect to nozzle, therefore
Referred to as cooling wind；These cooling wind channels can be handled as air nozzle, but it is along whole group burner nozzle height side
It is adjusted to being uniformly distributed, and without baffle, is always in normally open；For the object boiler, the cooling wind nozzle gross area is
1.81m2, the determination method of cooling wind wind speed is identical as air nozzle, the result of calculation of various air nozzles and cooling wind wind speed
Right number the 2nd arranges in being shown in Table 1.
Table 1
Utilize the Secondary Air pressure p=971Pa measured, Secondary Air temperature t2It=304.3 DEG C, is calculated according to formula (1)
Secondary Air density p2=0.62kg/m3；According to the air in the air nozzle area and table 1 provided in Secondary Air density, Fig. 1
Nozzle wind velocity calculates the air mass flow of each nozzle using formula (2), and right number the 1st arranges in the results are shown in Table 1；Due to every layer it is same comprising 4
The nozzle of sample, what which provided is the sum of the flow of 4 nozzles of same layer.
Boiler tetra- coal pulverizers of A, B, C, E that come into operation altogether in operation measure this four coal pulverizers using operational monitoring instrument
Coal-supplying amount be respectivelyAir mass flow point
It is notAccording to formula (3) and formula (4), meter
Calculate every coal nozzle Zhong Give coal flowAnd air mass flowN=4 in formula；In table 1 right number the 1st arrange in provide be
The coal flow and air mass flow of every layer of coal nozzle, they are the sum of the flows of 4 nozzles of same layer, i.e.,By
In a coal pulverizer only to 4 nozzle powder supplies of same layer, therefore, the sum of the flow of 4 nozzles of same layerBe exactly into
Enter the air mass flow of coal pulverizerHe Give coal flows
The boiler furnace is divided into 7 combustion zones shown in FIG. 1, the average excess air coefficient difference in these combustion zones
It is expressed as αA、αB、αC、αD、αE、αMZ、αSOFA；It is boundary, main burning area and after-flame that the division principle of combustion zone, which is with coal nozzle,
Wind area is respectively as independent section；The coal nozzle and air nozzle that each section is included are shown in Fig. 1；According to stove inner nozzle position
It sets and each nozzle flow that table 1 provides, is calculated according to formula (5) and formula (6) and enter each section total air mass flow and coal
Flow, wherein cooling wind flow are evenly distributed in the vertical height where whole group burner nozzle；To in each combustion zone
Nozzle flow is accumulated, and the air mass flow and pulverized coal flow for obtaining above-mentioned 7 combustion zones are shown in Table 2.
Table 2
The industrial components for taking raw coal sample that chemical laboratory is sent to chemically examine coal, result are：Air-dried moisture Mad=
2.72%, air-dried basis volatile matter Vad=29.85%, air-dried basis ash content Aad=23.64%, moisture as received coal point
Mar=11.60%；1 kilogram of required theoretical air requirement m of as-fired coal burning is calculated according to formula (7)0=6.925 (kg/kg).
According to the air mass flow M for entering certain combustion zone in table 2AWith coal flow MFAnd the theoretical air requirement m of coal0, utilize
Formula (8) calculates the excess air coefficient of the section, and the right number the 1st that the results are shown in Table in 2 arranges.
For ease of the monitoring of operations staff, along the air mass flow of furnace height and the distribution core of coal flow at column diagram,
Fig. 3 is to be distributed column diagram according to the wind powder that result of calculation is drawn, it more intuitively shows that wind powder is distributed in stove.
Excess air coefficient more can accurately reflect that wind powder distribution situation in stove, Fig. 4 are drawn according to result of calculation in stove
Excess air coefficient with the variation of furnace height, wherein the excess air coefficient in main burning area is 0.73, and separation burnout degree goes out
The excess air coefficient of mouth is 1.08.
According to monitoring result, operations staff can adjust oven air flow rate and the distribution to coal flow, for example, operation people
Member wants to weaken the intensity of main burning area air classification, the excess air coefficient in the area is increased to 0.75, they keep into stove
, the baffle opening of Kai great main burning area air nozzle constant to coal flow of coal quality and coal pulverizer, by the spray of stove inner second air air
Baffle opening and bellows-furnace outlet differential pressure of mouth are adjusted to following state：
Bellows-furnace outlet differential pressure Δ P=960Pa；
Secondary Air pressure p=928Pa；
Secondary Air temperature t2=304.0 DEG C；
Each secondary air damper aperture is respectively in Fig. 1：
XSOFA4=100%
XSOFA3=100%
XSOFA2=100%
XSOFA1=100%
XEE=30%
XE=100%
XDE=30%
XD=0%
XCD=30%
XC=100%
XBC=30%
XB=100%
XAB=30%
XA=100%
XAA=50%
Using the above method, monitor that the excess air coefficient of each combustion zone is respectively：
A coal burners combustion zone below, αA=0.75
B coal burners combustion zone below, αB=0.68
C coal burners combustion zone below, αC=0.67
D coal burners combustion zone below, αD=0.74
E coal burners combustion zone below, αE=0.71
Main burning area exports, αMZ=0.75
Detach the outlet of burnout degree area, αSOFA=1.12.
Above-mentioned, although the foregoing specific embodiments of the present invention is described with reference to the accompanying drawings, not protects model to the present invention
The limitation enclosed, those skilled in the art should understand that, based on the technical solutions of the present invention, those skilled in the art are not
Need to make the creative labor the various modifications or changes that can be made still within protection scope of the present invention.
Claims (5)
1. a kind of method monitoring wind powder distribution in low NOx tangential firing boilers stove, characterized in that including：
(1) under the non-ignition condition of boiler cold-state, drag characteristic experiment is carried out to secondary air damper, respectively obtains secondary air damper
Resistance coefficient and burner hearth resistance coefficient；
It is monitored when being run according to the resistance coefficient and boiler thermal-state of the resistance coefficient of secondary air damper obtained above and burner hearth
Secondary air box-furnace outlet differential pressure, Secondary Air pressure and temperature parameter, calculate the wind of overfire air jet when hot operation
Speed；
(2) the Secondary Air pressure and temperature when operation of acquisition boiler thermal-state, calculates Secondary Air density；It is close according to the Secondary Air
The area of degree, the wind speed of overfire air jet and overfire air jet, obtains the air mass flow of each overfire air jet；
(3) measure coal pulverizer give coal flow and air mass flow, be evenly distributed to the mill to coal flow and air mass flow by described
Each coal nozzle corresponding to coal machine；
(4) it is boundary with coal nozzle position, burner hearth is divided into several burning blocks；According to each overfire air jet and pulverized coal injection
Position of the mouth in burner hearth, and the air mass flow and pulverized coal flow of these nozzles are flowed through, it calculates and enters each burning block in stove
Air mass flow and coal flow；
The computational methods of the air mass flow of certain burning block are in into stove：To the coal dust of all operation coal pulverizers in the combustion zone
Cumulative and with the air mass flow of all overfire air jets in the combustion zone the cumulative and summation of the air mass flow of nozzle；
The computational methods of the coal flow of certain burning block are in into stove：The coal flow of all operation coal pulverizers in the combustion zone
It is cumulative and；
(5) it is taken into stove coal sample, according to the industrial components of as-fired coal sample, the required theoretical air of unit of account as-fired coal burning
Amount；
Specific method is：
Wherein, m0For the required theoretical air requirement of as-fired coal burning, FCadCarbon content is fixed for the air-dried basis of as-fired coal,
VadFor the air-dried basis volatile matter content of as-fired coal, AadFor the air-dried basis content of ashes of as-fired coal, MarFor as-fired coal
Moisture as received coal content；
(6) according to the calculated value of air mass flow and coal flow in burner hearth burning block, and it is required to be incorporated into stove coal combustion
Theoretical air requirement obtains the excess air coefficient of the burning block, it illustrates the wind powder distribution of the burner hearth burning block；
The method of excess air coefficient for calculating burning block is：
The ratio of the sum of air mass flow into the burning block and the theoretical air requirement needed for the coal flow for entering the combustion zone.
2. a kind of method monitoring wind powder distribution in low NOx tangential firing boilers stove as described in claim 1, characterized in that
The method of calculating Secondary Air density is specially in the step (2)：
According to the relational expression of the pressure of perfect gas, density and temperature, in conjunction with local atmospheric pressure, Secondary Air pressure and secondary
Air temperature calculates Secondary Air density.
3. a kind of method monitoring wind powder distribution in low NOx tangential firing boilers stove as described in claim 1, characterized in that
The method of the air mass flow of calculating overfire air jet is in the step (2)：
The air mass flow of overfire air jet is directly proportional to the product of the wind speed of the area of the nozzle, Secondary Air density and the nozzle；
According to Secondary Air density, the area of the wind speed of overfire air jet and overfire air jet, the air mass flow of overfire air jet is obtained.
4. a kind of method monitoring wind powder distribution in low NOx tangential firing boilers stove as described in claim 1, characterized in that
In the step (3), assigned by each coal nozzle is to coal flow：Coal pulverizer gives coal flow and the coal pulverizer institute
The ratio of corresponding coal nozzle quantity；
Air mass flow assigned by each coal nozzle is：The air mass flow of coal pulverizer and the coal dust corresponding to the coal pulverizer
The ratio of nozzle quantity.
5. a kind of method monitoring wind powder distribution in low NOx tangential firing boilers stove as described in claim 1, characterized in that
In the step (4), the separation after-flame in main burning area and upper furnace that lower furnace portion coal nozzle and air nozzle are formed
Wind combustion zone is respectively as independent burning block.
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| CN107741028A (en) * | 2017-10-23 | 2018-02-27 | 新疆电力建设调试所有限责任公司 | The small air door cold and hot state fitting control method of quadrangle tangential circle pulverized-coal fired boiler Secondary Air |
| CN108763651B (en) * | 2018-04-28 | 2022-04-12 | 国网山东省电力公司电力科学研究院 | Method for extracting flow passing characteristic of air distribution baffle of combustor from boiler operation data |
| CN108800191B (en) * | 2018-06-29 | 2019-06-04 | 国网山东省电力公司电力科学研究院 | A kind of Dynamic Optimum method of tangential firing boiler Secondary Air air distribution |
| CN111023071A (en) * | 2018-10-10 | 2020-04-17 | 中国石油化工股份有限公司 | Operation method of SCR denitration pulverized coal boiler |
| CN110369057B (en) * | 2019-07-02 | 2021-05-18 | 大唐湘潭发电有限责任公司 | Method for acquiring coal powder flow of powder pipe in double-inlet and double-outlet steel ball milling direct-blowing type powder making system |
| CN110397949A (en) * | 2019-07-24 | 2019-11-01 | 杭州涌复科技有限公司 | A kind of establishment method of power boiler burning intelligence air distribution model |
| CN112696657B (en) * | 2020-12-01 | 2023-03-10 | 北方联合电力有限责任公司包头第一热电厂 | Boiler blowing-out control system |
| CN112628712A (en) * | 2021-01-11 | 2021-04-09 | 大唐黄岛发电有限责任公司 | Secondary air closed-loop optimization control system based on air door resistance coefficient |
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| US7484956B2 (en) * | 2003-09-16 | 2009-02-03 | Praxair Technology, Inc. | Low NOx combustion using cogenerated oxygen and nitrogen streams |
| CN102734833A (en) * | 2012-06-07 | 2012-10-17 | 中国神华能源股份有限公司 | Boiler optimization method for reducing nitrogen oxide discharge |
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