CN109268824A - A kind of front-back wall combustion system boiler combustion control method - Google Patents
A kind of front-back wall combustion system boiler combustion control method Download PDFInfo
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- CN109268824A CN109268824A CN201811163008.4A CN201811163008A CN109268824A CN 109268824 A CN109268824 A CN 109268824A CN 201811163008 A CN201811163008 A CN 201811163008A CN 109268824 A CN109268824 A CN 109268824A
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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
- F23C10/00—Fluidised bed combustion apparatus
- F23C10/18—Details; Accessories
- F23C10/28—Control devices specially adapted for fluidised bed, combustion apparatus
Abstract
The invention discloses a kind of front-back wall combustion system boiler combustion control method, which uses high-ash bituminous coal, and controlling fineness of pulverized coal R90 is 8%-15%.High-ash bituminous coal progress fineness of pulverized coal control is being used to front-back wall burning boiler using control method of the present invention, fineness of pulverized coal is being can be effectively reduced, reduces boiler flyash carbon content, economizer exit NOXConcentration improves boiler efficiency and unit economy.
Description
Technical field
Control method when high-ash bituminous coal is used the present invention relates to front-back wall burning boiler.
Background technique
Station boiler is actually located at low nitrogen burning, use economic coal and middle-low load operation be overlapped mutually in the state of transport
Row produces many quite serious problems: the economic problems such as flying dust, slag phosphorus content increase, and spray water flux increases；Heating surface
Coking, burner hearth high temperature corrosion, the safety problems such as low-load combustion-stabilizing；NOx production is exceeded, and spray ammonia is excessive, the rings such as preheater blocking
Guarantor's problem.The solution or alleviation of the above problem, key problem in technology all point to fineness of pulverized coal.Thinner coal dust increases solid particle ratio
Surface area enhances precipitation, kindling, surely fires, burns each process, and to reducing, flying marking is advantageous, advantageous to low nitrogen burning；Phase
When reducing nitrogen in quickly touching oxygen in the more cokes in primary zone --- oxygen reaction generates NOX and enhances NOX
The physics probability and chemical kinetic energy, that is, the anoxic being furthermore achieved under excess air coefficient permanence condition for being converted to N2 are fired
It burns, to reducing, NOX is advantageous；Mean the smaller inertia of pulverized coal particle, reduces and boundary pyrolysis is thrown to by rotation flue gas, burns
Intensity improves burner hearth wall surface reproducibility atmosphere, and to mitigating, high temperature corrosion is advantageous.The reasonable selection of studying coal powder fineness, to solution
Certainly burning there are the problem of, have realistic price.
Summary of the invention
The purpose of the present invention is to solve defects existing in the prior art, provide a kind of for instructing front-back wall to burn
Boiler, to the adjustment of fineness of pulverized coal, reduces fineness of pulverized coal when using high-ash bituminous coal, reduces boiler flyash carbon content, economizer
Export NOXConcentration improves boiler efficiency and unit economy.
In order to achieve the above object, the present invention provides a kind of front-back wall combustion system boiler combustion control method, the pots
Furnace uses high-ash bituminous coal, and controlling fineness of pulverized coal R90 is 8%-15%, is preferably controlled in 10.8%-11.3%.
Direct step concretely are as follows:
Step 1: maintaining burnout degree ratio, operation oxygen amount, coal pulverizer operation number of units etc. under boiler low nitrogen burning state
Constant, by numerical simulation analysis difference fineness of pulverized coal to boiler combustion influence.
Step 2: field test research is carried out according to the numerical simulation result of the first step, under boiler low nitrogen burning state,
It maintains burnout degree ratio, Secondary Air air distribution mode, operation oxygen amount, coal pulverizer operation number of units etc. constant, passes through analysis of experiments difference
Influence of the fineness of pulverized coal to boiler combustion.
Step 3: determining best fineness of pulverized coal controlling value according to numerical simulation and experimental study.
It can determine that front-back wall burning boiler uses the best fineness of pulverized coal controlling value of high-ash bituminous coal by above adjustment,
Unburned carbon in flue dust and economizer exit NOx concentration are reduced, boiler efficiency and unit economy are improved.
More specifically:
(1) it under boiler low nitrogen burning state, maintains unit load 330MW and 165MW load constant, maintains burnout degree ratio
Example (30%), operation oxygen amount (3.6%-3.75%, 165MW load when 4.5%-4.75% when 330MW load), coal pulverizer operation
Number of units (ABD is ground when ABCD mill, 165MW load when 330MW load) etc. is constant, passes through numerical simulation analysis difference fineness of pulverized coal pair
The influence of boiler combustion.With FLUENT numerical simulation software suggestion mode, grid dividing, carrying out fineness of pulverized coal R90 is respectively
23%, 15%, 11% and 8% numerical simulation calculation；
(2) field test research is carried out according to the numerical simulation result of the first step, under boiler low nitrogen burning state, maintained
Burnout degree ratio (30%), operation oxygen amount (3.6%-3.75%, 165MW load when 4.5%-4.75% when 330MW load), mill
Coal machine operation number of units (ABD is ground when ABCD mill, 165MW load when 330MW load) etc. is constant, thin by analysis of experiments difference coal dust
Spend the influence to boiler combustion.
High-ash bituminous coal fineness of pulverized coal is being used eventually for front-back wall burning boiler according to obtained by the above guiding step
Control method is as follows:
Under boiler low nitrogen burning state, burnout degree ratio (30%), operation oxygen amount (3.6%- when 330MW load are maintained
3.75%, 165MW load when 4.5%-4.75%), coal pulverizer operation number of units (when 330MW load ABCD mill, 165MW load when
ABD mill) etc. constant, the influence by analysis of experiments difference fineness of pulverized coal to boiler combustion:
When 330MW load, A grinds power 45t/h, loading force 10MPa, mill import primary wind pressure 6.1kPa, mill import wind-warm syndrome
266 DEG C, hot air disperser aperture 100%, cold-air flap aperture 0%, dynamic separator frequency 25Hz, coal pulverizer inlet and outlet differential pressure
4.7kPa, fineness of pulverized coal R90 are 11%.B grinds power 42t/h, loading force 10MPa, mill import primary wind pressure 6.1kPa, mill import
266 DEG C of wind-warm syndrome, hot air disperser aperture 100%, cold-air flap aperture 0%, dynamic separator frequency 25Hz, coal pulverizer import and export differential pressure
4.8kPa, fineness of pulverized coal R90 are 11.3%.C grinds power 48t/h, loading force 10.5MPa, mill import primary wind pressure 6.1kPa, mill
264 DEG C of import wind-warm syndrome, hot air disperser aperture 100%, cold-air flap aperture 0%, dynamic separator frequency 27Hz, coal pulverizer inlet and outlet are poor
Pressing 4.7kPa, fineness of pulverized coal R90 is 11.3%.
When 165MW load, A grinds power 48t/h, loading force 10.5MPa, mill import primary wind pressure 6.2kPa, mill import wind
268 DEG C of temperature, hot air disperser aperture 100%, cold-air flap aperture 0%, dynamic separator frequency 28Hz, coal pulverizer import and export differential pressure
4.8kPa, fineness of pulverized coal R90 are 10.8%.B grinds power 46t/h, loading force 10.5MPa, mill import primary wind pressure 6.2kPa, mill
270 DEG C of import wind-warm syndrome, hot air disperser aperture 100%, cold-air flap aperture 0%, dynamic separator frequency 28Hz, coal pulverizer inlet and outlet are poor
Pressing 4.8kPa, fineness of pulverized coal R90 is 11.2%.
The present invention has the advantage that compared with prior art
High-ash bituminous coal progress fineness of pulverized coal control, energy are being used to front-back wall burning boiler using control method of the present invention
Fineness of pulverized coal is enough effectively reduced, reduces boiler flyash carbon content, economizer exit NOXConcentration improves boiler efficiency and unit warp
Ji property.
Detailed description of the invention
Fig. 1 is the present invention to Guo electricity Shizuishan power plant 1# furnace numerical simulation three-dimensional and grid chart；
Fig. 2 is the comparison diagram of 330MW load difference fineness of pulverized coal lower hearth thermo parameters method；
Fig. 3 is that burner nozzle volatile matter profiles versus schemes under 330MW load difference fineness of pulverized coal；
Fig. 4 is 330MW load difference fineness of pulverized coal lower hearth CO concentration distribution comparison diagram；
Fig. 5 is 330MW load difference fineness of pulverized coal lower hearth NOxConcentration distribution comparison diagram；
Fig. 6 is coal dust under 330MW load difference fineness of pulverized coal in burner hearth residence time comparison diagram；
Fig. 7 is the comparison diagram of 165MW load difference fineness of pulverized coal lower hearth thermo parameters method；
Fig. 8 is that burner nozzle volatile matter profiles versus schemes under 165MW load difference fineness of pulverized coal；
Fig. 9 is 165MW load difference fineness of pulverized coal lower hearth CO concentration distribution comparison diagram；
Figure 10 is 165MW load difference fineness of pulverized coal lower hearth NOxConcentration distribution comparison diagram；
Figure 11 is coal dust under 165MW load difference fineness of pulverized coal in burner hearth residence time comparison diagram.
Specific embodiment
The present invention is described in detail combined with specific embodiments below.
The embodiment of the present invention is Wuhan with Guo electricity Shizuishan electricity generating corporation, Ltd 1# boiler model WGZ1004-18.4-2
The subcritical Natural Circulation dum boiler that boiler factory manufactures.Boiler use medium-speed pulverizer blow-through pulverized coal preparation system, tail portion twin flue,
Gas baffle adjusts reheat steam temperature, and spray desuperheating adjusts overheating steam temperature, intermediate single reheat, balanced draft, three points of capacity gram formulas
Air preheater, submerged slag conveyor continuous solid-state deslagging, all steel framework, overhung construction, the above are closed seals for operation level of boiler
Island arrangement, uses high-ash bituminous coal.
Three layer arrangement of burner hearth front wall point 18 is double to adjust wind axial rotational flow burner, and rear wall paper sets 6 double tune wind axial rotational flows
Burner, successively A, B, C layers from bottom to top of every layer of six front wall, latter wall D layers with the A layers of arrangement that liquidates, four MPS225 medium-speed pulverizers
Coal machine is corresponding, and every grinding-in is for an electronic-weighing belt coal feeder.There was only ABC3 platform grinding belt coal dust fortune in actual motion
Row, D mill only have centre wind to be cooled down without coal dust operation.Boiler main design parameters are shown in Table 1.
Boiler main design parameters see the table below 1.
1 Boiler Main Parameter table (design coal) of table
Front-back wall burning boiler of the present invention uses the numerical simulation of high-ash bituminous coal fineness of pulverized coal control method and test is ground
In studying carefully, coal is power plant design coal, and coal is shown in Table 2.
2 boiler design coal data of table
Embodiment 1 (330MW load)
The coal pulverizer that the present embodiment specifically puts into operation is ABCD4 platform coal pulverizer.
Front-back wall combustion system boiler of the present invention uses high-ash bituminous coal fineness of pulverized coal control method, and specific step is as follows:
(1) it under boiler low nitrogen burning state, maintains unit load 330MW load constant, maintains burnout degree ratio
(30%), it is constant that oxygen amount (3.6%-3.75%), coal pulverizer operation number of units (ABCD mill) etc. are run, not by numerical simulation analysis
Influence with fineness of pulverized coal to boiler combustion.With FLUENT numerical simulation software suggestion mode, grid dividing, it is thin to carry out coal dust
Degree R90 is respectively 23%, 15%, 11% and 8% numerical simulation calculation；
(2) field test research is carried out according to the numerical simulation result of the first step, under boiler low nitrogen burning state, maintained
Burnout degree ratio (30%), operation oxygen amount (330MW load when 3.6%-3.75%), coal pulverizer operation number of units are (when 330MW load
ABCD mill) etc. constant, the influence by analysis of experiments difference fineness of pulverized coal to boiler combustion.
When 330MW load, A grinds power 45t/h, loading force 10MPa, mill import primary wind pressure 6.1kPa, mill import wind-warm syndrome
266 DEG C, hot air disperser aperture 100%, cold-air flap aperture 0%, dynamic separator frequency (15Hz, 20Hz, 25Hz, 28Hz), coal-grinding
Machine import and export differential pressure (4.0kPa, 4.3kPa, 4.7kPa, 4.9kPa), fineness of pulverized coal R90 be respectively (23.4%, 15.5%,
11%, 8.2%).B grinds power 42t/h, loading force 10MPa, mill import primary wind pressure 6.1kPa, 266 DEG C of import wind-warm syndrome of mill, heat
Throttle opening 100%, cold-air flap aperture 0%, dynamic separator frequency (15Hz, 19Hz, 25Hz, 29Hz), coal pulverizer inlet and outlet
Differential pressure (4.2kPa, 4.5kPa, 4.8kPa, 5.0kPa), fineness of pulverized coal R90 are (23.1%, 15.0%, 11.3%, 8.3%).C
Grind power 48t/h, loading force 10.5MPa, mill import primary wind pressure 6.1kPa, mill 264 DEG C of import wind-warm syndrome, hot air disperser aperture
100%, cold-air flap aperture 0%, dynamic separator frequency (17Hz, 21Hz, 27Hz, 30Hz), coal pulverizer import and export differential pressure
(4.0kPa, 4.5kPa, 4.7kPa, 5.0kPa), fineness of pulverized coal R90 are (23.2%, 15.2%, 11.3%, 8.0%).
(3) numerical simulation and experimental study are combined, when front-back wall combustion system boiler low nitrogen burning state uses high ash content
Pulverized bituminous coal fineness (R90) Optimal Control value is 11% or so.
1, numerical simulation analysis process and result
This simulation is by being modeled and being simulated to full burner hearth.Fig. 1 is the grid dividing situation of boiler model, in order to more quasi-
The combustion case of true reaction primary combustion zone, takes encryption to the grid of each burner position of primary combustion zone.
The hearth combustion flame kernel and temperature change of this simulation main research transformation front and back, therefore in this simulation
The heat absorption situation of heating surface is not studied in detail.
Under 330MW load, ABCD mill operation only has ABC grinding belt coal dust, D when actual motion after low NO transformation
It grinds and only leads to the operation that centre wind carries out cooling without coal dust.After considering the transformation of boiler low nitrogen burning, burnout degree ratio is maintained about
30%, Secondary Air air distribution mode, operation oxygen amount, coal pulverizer operation number of units etc. are constant, change fineness of pulverized coal (R90 is respectively 23%,
15%, 11% and 8%), analysis fineness of pulverized coal changes the influence to burning.It is according to version " firepower in 2012 that wherein R90, which is 23%,
Power plant pulverized coal preparation system design computing technique regulation " --- recommend calculation formula to be calculated in DL/T5145-2012, R90=
0.5nVdaf, wherein n is pulverized coal fineness index, VdafFor coal dry ash free basis volatile matter.Numerical simulation operating condition is shown in Table 3.Mould
It is quasi- to the results are shown in Table 4, Fig. 2-Fig. 6.
Different fineness of pulverized coal numerical simulation operating conditions under 3 330MW of table
Different fineness of pulverized coal numerical simulation results under 4 330MW of table
330MW load, burnout degree ratio 30% or so, unit low nitrogen burning side it can be seen from table 3- table 4, Fig. 2-Fig. 6
Under formula, it is more apparent to combustion effects to change fineness of pulverized coal.
(1) reduction to attenuate with coal dust, the specific surface area that the coal dust of unit mass is contacted with hot fume in oxygen and furnace
Become larger, kindling earlier, after-flame is more thorough, and heat release is more in the case where identical coal dust amount, thus burner hearth bulk temperature level compared with
Original operating condition is slightly higher.
(2) it reduces coal powder size and is conducive to after-flame, unburned carbon in flue dust is gradually decreased by operating condition 1 to operating condition 4.Fineness of pulverized coal by
23% when being reduced to 11%, and unburned carbon in flue dust drops to 1.5% by 4.41%, reduces about 2.9 percentage points.
(3) reduce coal particle size to be conducive to pulverized coal particle and enter its internal volatile matter of burner hearth early stage faster more thoroughly to analyse
Combustion reaction is participated in out, therefore the volatile matter concentration in burner hearth primary zone increases with CO concentration with the reduction of coal particle size.
(4) with the reduction of coal particle size, the NOx concentration of furnace outlet is gradually reduced.Operating condition 2,3,4 is compared under operating condition 1
Furnace outlet NOx concentration reduces about 17.41%, 22.67% and 24.34% respectively.
2, process and result are tested
Keep total coal amount, operation oxygen amount, SOFA wind ratio, pulverizer capacity, loading force, entrance primary wind pressure etc. constant,
4 change dynamic separator frequency operating conditions are carried out.
Under boiler low nitrogen burning state, burnout degree ratio (30%), operation oxygen amount (3.6%- when 330MW load are maintained
3.75%, 165MW load when 4.5%-4.75%), coal pulverizer operation number of units (when 330MW load ABCD mill, 165MW load when
ABD mill) etc. constant, the influence by analysis of experiments difference fineness of pulverized coal to boiler combustion.
Under boiler low nitrogen burning state, burnout degree ratio (30%), operation oxygen amount (3.6%- when 330MW load are maintained
3.75%, 165MW load when 4.5%-4.75%), coal pulverizer operation number of units (when 330MW load ABCD mill, 165MW load when
ABD mill) etc. constant, the influence by analysis of experiments difference fineness of pulverized coal to boiler combustion.
Boiler thermal efficiency, subsidiary engine power consumption are tested under different operating conditions.The unit method of operation is shown in Table 5.Furnace effect calculates under each operating condition
Parameter is shown in Table 6.
The 5 330MW load change state separator revolving speed unit method of operation of table
6 330MW load difference separator speed conditions boiler thermal efficiency test result table of table
3, best fineness of pulverized coal is determined
Under 330MW load, burnout degree ratio 30% or so, unit low nitrogen burning mode it can be seen from table 5- table 6, change
Become fineness of pulverized coal, is found by experiment that more apparent to combustion effects.
(1) it reduces coal powder size and is conducive to after-flame, unburned carbon in flue dust is gradually decreased by operating condition 1 to operating condition 4.Fineness of pulverized coal by
23% when being reduced to 11%, and unburned carbon in flue dust drops to 1.35% by 4.58%, reduces about 3.23 percentage points, slag phosphorus content
It is reduced to 3% by 4.1%, reduces by 1.1 percentage points, boiler efficiency is improved by 90.9% to 93.2%, improves 2.3 percentages
Point.
(2) with the reduction of coal particle size, it is decrescence small to overheat spray water flux.When fineness of pulverized coal is reduced to 11% by 23%,
Overheat spray water flux drops to 10t/h by 16t/h, reduces amplitude 37.5%.
(3) with the reduction of coal particle size, coal pulverizer power consumption is in increase trend.Fineness of pulverized coal is reduced to 11% by 23%
When, coal pulverizer power consumption increases 152kW.h, amplification about 11.7%.
(4) with the reduction of coal particle size, the NOx concentration of furnace outlet is gradually reduced.Operating condition 2,3,4 is compared under operating condition 1
Furnace outlet NOx concentration reduces about 15.21%, 23.91% and 26.95% respectively.
It is found by experiment that, under 330MW load, the flying dust slag phosphorus content of numerical simulation under different fineness of pulverized coal operating conditions,
Economizer exit nitrous oxides concentration and full size field test result are not much different, and illustrate that numerical simulation is more accurate.Coal dust is thin
When degree R90 drops to 11% by 23%, flying dust, slag phosphorus content reduce more, 2.3 percentage points of boiler efficiency raising, nitrogen
Oxide reduces, overheats spray water flux reduction, and unit economy and the feature of environmental protection significantly improve.
When fineness of pulverized coal R90 is reduced to 8%, although unburned carbon in flue dust is reduced to 0.85%, slag phosphorus content is reduced to
2.4%, about 0.3 percentage point is improved when boiler efficiency is compared with fineness 11%, while coal pulverizer power consumption also increases about 200kW.h,
Fineness of pulverized coal reduces more, and discovery coal pulverizer differential pressure is also bigger during test, coal pulverizer safe and stable operation there is also risk,
When fineness of pulverized coal is reduced to 8%, coal dust firing more shifts to an earlier date, and there are the risks of scaling loss burner nozzle.Comprehensive analysis, high ash of burning
When dividing bituminous coal, fineness of pulverized coal R90 selection 11% or so is relatively rationally.
Embodiment 2 (165MW load)
The coal pulverizer that the present embodiment specifically puts into operation is ABD3 platform coal pulverizer.
Front-back wall combustion system boiler of the present invention uses high-ash bituminous coal fineness of pulverized coal control method, and specific step is as follows:
(1) it under boiler low nitrogen burning state, maintains unit load 165MW load constant, maintains burnout degree ratio
(30%), it is constant that oxygen amount (4.5%-4.75%), coal pulverizer operation number of units (ABD mill) etc. are run, not by numerical simulation analysis
Influence with fineness of pulverized coal to boiler combustion.With FLUENT numerical simulation software suggestion mode, grid dividing, it is thin to carry out coal dust
Degree R90 is respectively 23%, 15%, 11% and 8% numerical simulation calculation；
(2) field test research is carried out according to the numerical simulation result of the first step, under boiler low nitrogen burning state, maintained
Burnout degree ratio (30%), operation oxygen amount (4.5%-4.75%), coal pulverizer operation number of units (ABD mill) etc. are constant, pass through test
Analyze influence of the different fineness of pulverized coal to boiler combustion.
When 165MW load, A grinds power 48t/h, loading force 10.5MPa, mill import primary wind pressure 6.2kPa, mill import wind
268 DEG C of temperature, hot air disperser aperture 100%, cold-air flap aperture 0%, dynamic separator frequency 28Hz, coal pulverizer import and export differential pressure
4.8kPa, fineness of pulverized coal R90 are 10.8%.B grinds power 46t/h, loading force 10.5MPa, mill import primary wind pressure 6.2kPa, mill
270 DEG C of import wind-warm syndrome, hot air disperser aperture 100%, cold-air flap aperture 0%, dynamic separator frequency 28Hz, coal pulverizer inlet and outlet are poor
Pressing 4.8kPa, fineness of pulverized coal R90 is 11.2%.
(3) numerical simulation and experimental study are combined, when front-back wall combustion system boiler low nitrogen burning state uses high ash content
Pulverized bituminous coal fineness (R90) Optimal Control value is 11%.
1, numerical simulation analysis process and result
Under 165MW load, ABD mill operation only has AB grinding belt coal dust, D mill when actual motion after low NO transformation
Only lead to centre wind without coal dust and carries out cooling operation.After considering the transformation of boiler low nitrogen burning, maintenance burnout degree ratio about 30%,
Secondary Air air distribution mode, operation oxygen amount, coal pulverizer operation number of units etc. are constant, change fineness of pulverized coal (R90 is respectively 23%, 15%,
11% and 8%), analysis fineness of pulverized coal changes the influence to burning.Numerical simulation operating condition is shown in Table 7.Analog result is shown in Table 8, Fig. 7-
Figure 11.
Different fineness of pulverized coal numerical simulation operating conditions under 7 165MW of table
Different fineness of pulverized coal numerical simulation results under 8 165MW of table
165MW load, burnout degree ratio 30% or so, unit low nitrogen burning it can be seen from table 7- table 8, Fig. 7-Figure 11
Under mode, it is more apparent to combustion effects to change fineness of pulverized coal.
(1) reduction to attenuate with coal dust, the specific surface area that the coal dust of unit mass is contacted with hot fume in oxygen and furnace
Become larger, kindling earlier, after-flame is more thorough, and heat release is more in the case where identical coal dust amount, thus burner hearth bulk temperature level compared with
Original operating condition is slightly higher.
(2) it reduces coal powder size and is conducive to after-flame, unburned carbon in flue dust is gradually decreased by operating condition 5 to operating condition 8.Fineness of pulverized coal by
23% when being reduced to 11%, and unburned carbon in flue dust drops to 0.4% by 2.60%, reduces about 2.2 percentage points.
(3) reduce coal particle size to be conducive to pulverized coal particle and enter its internal volatile matter of burner hearth early stage faster more thoroughly to analyse
Combustion reaction is participated in out, therefore the volatile matter concentration in burner hearth primary zone increases with CO concentration with the reduction of coal particle size.
(4) with the reduction of coal particle size, the NOx concentration of furnace outlet is gradually reduced.Operating condition 6,7,8 is compared under operating condition 5
Furnace outlet NOx concentration reduces about 16.5%, 24.6% and 30.8% respectively.
For station boiler when depth low nitrogen burning state, using high-ash bituminous coal, the variation of fineness of pulverized coal is to boiler fly ash
Phosphorus content, economizer exit NOXConcentration, fire box temperature field and burner hearth CO concentration influence more apparent.Fineness of pulverized coal is by 23% decline
When to 11%, unburned carbon in flue dust reduces 2.2-2.9 percentage points, economizer exit NOXConcentration decline about 25%.Station boiler is deep
It is best in order to reach unit economy and the feature of environmental protection when spending low nitrogen burning state, using high-ash bituminous coal, it is run in pulverized coal preparation system
Fineness of pulverized coal operation is reduced under the premise of Safety and allowable as far as possible.In order to guarantee pulverized coal preparation system long-term safety and burner nozzle safety
Property, by numerical simulation determine front and back phase burning boiler use high-ash bituminous coal when fineness of pulverized coal R90 control 11% or so compared with
It is good
2, experimental study process and result
Keep total coal amount, operation oxygen amount, SOFA wind ratio, pulverizer capacity, loading force, entrance primary wind pressure etc. constant,
4 change dynamic separator frequency operating conditions are carried out.
Boiler thermal efficiency, subsidiary engine power consumption are tested under different operating conditions.The unit method of operation is shown in Table 9.Furnace effect calculates under each operating condition
Parameter is shown in Table 10.
The 9 165MW load change state separator revolving speed unit method of operation of table
10 165MW load difference separator speed conditions boiler thermal efficiency test result table of table
3, best fineness of pulverized coal is determined
Under 165MW load, burnout degree ratio 30% or so, unit low nitrogen burning mode it can be seen from table 9- table 10, change
Become fineness of pulverized coal, is found by experiment that more apparent to combustion effects.
(1) it reduces coal powder size and is conducive to after-flame, unburned carbon in flue dust is gradually decreased by operating condition 5 to operating condition 8.Fineness of pulverized coal by
23% when being reduced to 11%, and unburned carbon in flue dust drops to 0.6% by 2.85%, reduces about 2.25 percentage points, slag phosphorus content
It is reduced to 2.4% by 3.8%, reduces by 1.4 percentage points, boiler efficiency is improved by 90.02% to 93.65%, improves 3.63
Percentage point.
(2) with the reduction of coal particle size, it is decrescence small to overheat spray water flux.When fineness of pulverized coal is reduced to 11% by 23%,
Overheat spray water flux drops to 5t/h by 9t/h, reduces amplitude 44.4%.
(3) with the reduction of coal particle size, coal pulverizer power consumption is in increase trend.Fineness of pulverized coal is reduced to 11% by 23%
When, coal pulverizer power consumption increases 100kW.h, amplification about 10%.
(4) with the reduction of coal particle size, the NOx concentration of furnace outlet is gradually reduced.Operating condition 6,7,8 is compared under operating condition 5
Furnace outlet NOx concentration reduces about 11.01%, 18.42% and 23.68% respectively.
It is found by experiment that, under 165MW load, the flying dust slag phosphorus content of numerical simulation under different fineness of pulverized coal operating conditions,
Economizer exit nitrous oxides concentration and full size field test result are not much different, and illustrate that numerical simulation is more accurate.Coal dust is thin
When degree R90 drops to 11% by 23%, flying dust, slag phosphorus content reduce more, 3.63 percentage points of boiler efficiency raising, nitrogen
Oxide reduces, overheats spray water flux reduction, and unit economy and the feature of environmental protection significantly improve.
When fineness of pulverized coal R90 is reduced to 8%, although unburned carbon in flue dust is reduced to 0.60%, slag phosphorus content is reduced to
2.0%, about 0.06 percentage point is improved when boiler efficiency is compared with fineness 11%, while coal pulverizer power consumption also increases about 200kW.h,
Fineness of pulverized coal reduces more, and discovery coal pulverizer differential pressure is also bigger during test, coal pulverizer safe and stable operation there is also risk,
When fineness of pulverized coal is reduced to 8%, coal dust firing more shifts to an earlier date, and there are the risks of scaling loss burner nozzle.Comprehensive analysis, high ash of burning
When dividing bituminous coal, fineness of pulverized coal R90 selection 11% or so is relatively rationally.
Claims (4)
1. a kind of front-back wall combustion system boiler combustion control method, it is characterised in that: the boiler uses high-ash bituminous coal, and
Control fineness of pulverized coal R90 is 8%-15%.
2. method for controlling combustion according to claim 1, it is characterised in that: the fineness of pulverized coal R90 control is 10.8%-
11.3%。
3. method for controlling combustion according to claim 2, it is characterised in that: the method for controlling combustion are as follows: low in boiler
It under nitrogen combustion state, maintains unit load 330MW constant, maintains burnout degree ratio 30%, operation oxygen amount 3.6%-3.75%, coal-grinding
ABCD mill is constant when machine runs number of units, and controls operation of coal pulverizing mills are as follows: A grinds power 45t/h, loading force 10MPa, mill import
Primary wind pressure 6.1kPa, mill 266 DEG C of import wind-warm syndrome, hot air disperser aperture 100%, cold-air flap aperture 0%, dynamic separator frequency
25Hz, coal pulverizer inlet and outlet differential pressure 4.7kPa, fineness of pulverized coal R90 are 11%；B grinds power 42t/h, loading force 10MPa, mill import
Primary wind pressure 6.1kPa, mill 266 DEG C of import wind-warm syndrome, hot air disperser aperture 100%, cold-air flap aperture 0%, dynamic separator frequency
25Hz, coal pulverizer inlet and outlet differential pressure 4.8kPa, fineness of pulverized coal R90 are 11.3%；C grinds power 48t/h, loading force 10.5MPa, mill
Import primary wind pressure 6.1kPa, mill 264 DEG C of import wind-warm syndrome, hot air disperser aperture 100%, cold-air flap aperture 0%, dynamic separator frequency
27Hz, coal pulverizer inlet and outlet differential pressure 4.7kPa, fineness of pulverized coal R90 are 11.3%；D mill only has centre wind to be cooled down without coal dust
Operation.
4. method for controlling combustion according to claim 2, it is characterised in that: the method for controlling combustion are as follows: low in boiler
It under nitrogen combustion state, maintains unit load 165MW constant, maintains burnout degree ratio 30%, operation oxygen amount 4.5%-4.75%, coal-grinding
ABD mill is constant when machine runs number of units, and controls operation of coal pulverizing mills are as follows: A grind power 48t/h, loading force 10.5MPa, grind into
Mouth primary wind pressure 6.2kPa, mill 268 DEG C of import wind-warm syndrome, hot air disperser aperture 100%, cold-air flap aperture 0%, dynamic separator frequency
28Hz, coal pulverizer inlet and outlet differential pressure 4.8kPa, fineness of pulverized coal R90 are 10.8%；B grinds power 46t/h, loading force 10.5MPa, mill
Import primary wind pressure 6.2kPa, mill 270 DEG C of import wind-warm syndrome, hot air disperser aperture 100%, cold-air flap aperture 0%, dynamic separator frequency
28Hz, coal pulverizer inlet and outlet differential pressure 4.8kPa, fineness of pulverized coal R90 are 11.2%；D mill only has centre wind to be cooled down without coal dust
Operation.
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Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103574633A (en) * | 2013-10-23 | 2014-02-12 | 广东电网公司电力科学研究院 | Method for regulating combustion of high-volatile bituminous coal for lean coal boiler |
| CN107355774A (en) * | 2016-06-02 | 2017-11-17 | 中国大唐集团科学技术研究院有限公司 | The method for reducing W type flame boiler unburned carbon in flue dust |
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Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103574633A (en) * | 2013-10-23 | 2014-02-12 | 广东电网公司电力科学研究院 | Method for regulating combustion of high-volatile bituminous coal for lean coal boiler |
| CN107355774A (en) * | 2016-06-02 | 2017-11-17 | 中国大唐集团科学技术研究院有限公司 | The method for reducing W type flame boiler unburned carbon in flue dust |
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| 李永华、杨卧龙、常建刚、魏刚、郑立国: "电站锅炉经济煤粉细度的选择与优化分析", 《锅炉技术》 * |
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