CN103968412B - The acquisition methods of combustion characteristics under different CCOFA wind and SOFA wind ratio after boiler improvement - Google Patents
The acquisition methods of combustion characteristics under different CCOFA wind and SOFA wind ratio after boiler improvement Download PDFInfo
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Abstract
After the invention discloses a kind of boiler improvement, the acquisition methods of combustion characteristics under different CCOFA wind and SOFA wind ratio, belongs to coal-burning boiler technical field.The method sets up the structured grid model of this boiler after carrying out stress and strain model by the corner tangential firing formula boiler that transformation is added SOFA wind, and obtains the burner parameter of described boiler, boundary condition parameter and coal dust parameter; Then founding mathematical models carries out combustion simulation calculating on the basis of the above, obtains the combustion characteristics of boiler under different CCOFA wind and SOFA wind ratio.Employing the method can reproduce the combustion case in boiler accurately, obtains the comprehensive information of boiler combustion situation, thus provides guidance and the improved effect of low nitrogen to carry out thoroughly evaluating to the low nitrogen transformation of boiler increase SOFA wind.
Description
Technical field
The present invention relates to coal-burning boiler technical field, the acquisition methods of combustion characteristics under different CCOFA wind and SOFA wind ratio after particularly relating to a kind of boiler improvement.
Background technology
Along with the severe situation of environmental improvement, China is to the discharge restriction of NOx by increasingly stringent, and national environmental protection portion has promulgated " thermal power plant's nitrogen oxide technological policy for treatment ", clearly will advance the preventing and controlling of China NOx in " 12 " period with all strength.The technology of current home and abroad station boiler implosion NOx mainly contains 2 kinds: one controls to generate, and mainly changes burning of coal condition by various technological means in combustion, thus reduce the growing amount of NOx, i.e. various low NOx technology; Two is the conversions after generating, and is mainly removed from flue gas by various technological means by the NOx generated, as selective catalytic reduction (SCR), SNCR method (SNCR) etc.
When power plant's NOx emission excessive concentration, by different means, boiler can be transformed, thus reduce the concentration of emission of NOx.But, current, also do not have a kind of method can simulate combustion case after the transformation of boiler low nitrogen in boiler, thus provide guidance and the improved effect of low nitrogen to carry out thoroughly evaluating to the transformation of boiler low nitrogen.
Summary of the invention
Based on this, the object of the invention is to the defect overcoming prior art, after providing a kind of boiler improvement, the acquisition methods of combustion characteristics under different CCOFA wind and SOFA wind ratio, adopts the method, can simulate the combustion case under different CCOFA wind and SOFA wind ratio in boiler after the transformation of low nitrogen.
For achieving the above object, the present invention takes following technical scheme:
The acquisition methods of combustion characteristics under different CCOFA wind and SOFA wind ratio after boiler improvement, comprises the following steps:
According to the design feature of corner tangential firing formula boiler, described boiler is carried out stress and strain model, set up the gridding structural model of this boiler; The structure of described boiler is be provided with CCOFA wind nozzle often organizing above burner, and above CCOFA wind nozzle, be provided with the SOFA wind nozzle installed in the level mode of liquidating;
Obtain the burner parameter of described boiler, boundary condition parameter and coal dust parameter;
According to above-mentioned gridding structural model, burner parameter, boundary condition parameter and coal dust parameter, gas-phase turbulent flow model is obtained with standard k-ε turbulence model simulation, with Hybrid analysis/probability density (ProbabilityDensityFunction, PDF) function model simulation obtains component transport and combustion model, pure coal combustion model is obtained with the simulation of unit fraction/probability density (PDF) function model, obtain mud with two mark/probability density (PDF) function model simulation and mix burning combustion model, pulverized coal particle motion model is obtained with stochastic particle tracking model simulation, the devolatilization model of coal is obtained with the parallel competitive reaction modeling of both sides' journey, coke combustion model is obtained with power/diffusion controlled reaction Rate Models simulation, radiation heat-transfer model is obtained with the simulation of P-1 radiation patterns,
Utilize above-mentioned model, change the ratio of CCOFA wind and SOFA wind, by analog computation, obtain the combustion characteristics of boiler under different CCOFA wind and SOFA wind ratio.
Wherein, CCOFA wind is compact burnout degree, and SOFA wind is for being separated burnout degree.
Wherein in an embodiment, described concrete steps of boiler being carried out stress and strain model comprise: in the mode of independent grid division, this boiler are divided into furnace hopper region, burner region, burner upper area and pendant superheater region.The not same-action played when boiler operatiopn according to each region, divides, improves the accuracy of this boiler gridding structural model.
Wherein in an embodiment, described concrete steps of boiler being carried out stress and strain model comprise: be encrypted by burner region, and the joint face of burner outlet and boiler is set to interface(interface).By above-mentioned setting, the precision of calculating can be improved, and can prevent the mesh quality in two faces and mesh shape from differing greatly and causing error.
Wherein in an embodiment, after setting up the structured grid model of described boiler, carry out the inspection of grid independence with the grid of different accuracy, choose the grid precision meeting computational accuracy and require.
Wherein in an embodiment, described boundary condition comprises the entrance boundary condition of centre wind, First air, Secondary Air, CCOFA wind, SOFA wind and surrounding air in boiler, the export boundary condition of the centre wind in boiler, First air, Secondary Air, CCOFA wind, SOFA wind and surrounding air, boiler wall boundary condition, heat exchange boundary condition;
The entrance boundary condition of the centre wind in described boiler, First air, Secondary Air, CCOFA wind, SOFA wind and surrounding air all adopts quality entrance boundary condition, this quality entrance boundary conditional parameter comprises mass flow, wind-warm syndrome parameter, and all set according to design parameter, wherein the quality entrance boundary conditional parameter of CCOFA wind, SOFA wind and surrounding air also calculates according to the working condition changing CCOFA wind and SOFA wind ratio;
The export boundary condition of the centre wind in described boiler, First air, Secondary Air, CCOFA wind, SOFA wind and surrounding air all adopts pressure export boundary condition, and pressure is set to-80Pa;
Described boiler wall boundary condition adopts standard law of wall equation, without slip boundary condition;
Described heat exchange boundary condition adopts second kind boundary condition (i.e. temperature boundary condition), and given default wall surface temperature and radiance, wherein, given wall surface temperature is 690K, and Wall Radiation rate is 0.8.
Analog computation result more accurately can be obtained with above-mentioned boundary condition.
Wherein in an embodiment, described coal dust parameter comprises coal particle size, coal content and content, and described coal particle size sets according to Rosin-Rammler location mode.Rosin-Rammler distribution supposition is at particle diameter d and the mass fraction Y of particle being greater than this diameter
dbetween there is exponential relationship:
for average diameter, n is profile exponent.
Wherein in an embodiment, described analog computation calculates with iterative method, first carries out cold conditions and calculates the flow field obtaining certain degree of convergence, and then carry out hot calculating, until convergence.
Wherein in an embodiment, in described analog computation, for pressure and the speed coupling employing SIMPLE Algorithm for Solving of discrete equation group, solving equation adopts by-line iterative method and the underrelaxation factor, makes the calculating residual error of NO and HCN parameter be less than 10
-8, the calculating residual error of all the other parameters is less than 10
-6.
Wherein in an embodiment, the combustion characteristics of described boiler comprises thermo parameters method situation, velocity field distribution situation and component field distribution situation.The combustion characteristics in boiler is embodied from many aspects.
Wherein in an embodiment, described thermo parameters method situation comprises: undermost Secondary Air Temperature Distribution, undermost First air Temperature Distribution, boiler center vertical cross-section Temperature Distribution, the distribution of boiler lateral cross section mean temperature along furnace height direction and the cigarette temperature of furnace outlet; Described velocity field distribution situation comprises: undermost Secondary Air VELOCITY DISTRIBUTION and orlop First air VELOCITY DISTRIBUTION; Described component field distribution situation comprises: O
2concentration is along the distribution in furnace height direction, CO concentration along the distribution in furnace height direction, the distribution of NOX concentration along furnace height direction and the NOX concentration of furnace outlet.
Compared with prior art, the present invention has following beneficial effect:
After boiler improvement of the present invention, the acquisition methods of combustion characteristics under different CCOFA wind and SOFA wind ratio, carries out stress and strain model by corner tangential firing formula boiler transformation being added SOFA wind, sets up the structured grid model of this boiler; Then founding mathematical models carries out combustion simulation calculating on the basis of the above, obtains the combustion characteristics of boiler under different CCOFA wind and SOFA wind ratio.Employing the method can reproduce the combustion case in boiler furnace accurately, obtains the comprehensive information of burner hearth combustion situation, thus provides guidance and the improved effect of low nitrogen to carry out thoroughly evaluating to the low nitrogen transformation of boiler increase SOFA wind.
The method is also to the gridding structural model how setting up boiler, and the step how founding mathematical models carries out combustion simulation calculating is optimized, through field demonstration, the result obtained by the method and the goodness of fit of situ measurements fine, ensure that the validity of analog result, the method has the high feature of the degree of accuracy.
Accompanying drawing explanation
Fig. 1 is boiler body schematic diagram;
Fig. 2 is burner cross sectional representation;
Fig. 3 is arrangement of nozzles mode schematic diagram;
Fig. 4 is SOFA wind mounting means schematic diagram;
Fig. 5 is SOFA wind nozzle arrangements schematic diagram;
Fig. 6 is boiler gridding structural model schematic diagram;
Fig. 7 is that boiler-burner area grid divides cross-sectional view;
Fig. 8 is under different CCOFA and SOFA wind ratio, undermost Secondary Air temperature profile, wherein: A is operating mode NO.1, B be operating mode NO.2, C be operating mode NO.3, D be operating mode NO.4, E be operating mode NO.5, F is the legend that different colours represents different temperatures;
Fig. 9 is under different CCOFA and SOFA wind ratio, undermost First air temperature profile, wherein: A is operating mode NO.1, B be operating mode NO.2, C be operating mode NO.3, D be operating mode NO.4, E is operating mode NO.5;
Figure 10 is under different CCOFA and SOFA wind ratio, boiler center vertical cross-section temperature profile, wherein: A is operating mode NO.1, B be operating mode NO.2, C be operating mode NO.3, D be operating mode NO.4, E is operating mode NO.5;
Figure 11 is under different CCOFA and SOFA wind ratio, boiler lateral cross section mean temperature is along furnace height directional spreding figure, wherein: A is whole boiler height distribution map, B is burner region height distribution map, C is CCOFA and SOFA wind region height distribution map, and D is the above region height distribution map of SOFA wind;
Figure 12 is under different CCOFA and SOFA wind ratio, furnace outlet gas temperature;
Figure 13 is under different CCOFA and SOFA wind ratio, undermost Secondary Air velocity contour, and wherein A is operating mode NO.1, B be operating mode NO.2, C be operating mode NO.3, D be operating mode NO.4, E is operating mode NO.5.
Figure 14 is under different CCOFA and SOFA wind ratio, undermost First air velocity contour, and wherein A is operating mode NO.1, B be operating mode NO.2, C be operating mode NO.3, D be operating mode NO.4, E is operating mode NO.5.
Figure 15 is under different CCOFA and SOFA wind ratio, O
2concentration is along furnace height directional spreding figure, and wherein: A is whole boiler height distribution map, B is burner region height distribution map, and C is CCOFA and SOFA wind region height distribution map, and D is the above region height distribution map of SOFA wind;
Figure 16 is under different CCOFA and SOFA wind ratio, CO concentration is along furnace height directional spreding figure, and wherein: A is whole boiler height distribution map, B is burner region height distribution map, C is CCOFA and SOFA wind region height distribution map, and D is the above region height distribution map of SOFA wind;
Figure 17 is under different CCOFA and SOFA wind ratio, NOx concentration is along furnace height directional spreding figure, and wherein: A is whole boiler height distribution map, B is burner region height distribution map, C is CCOFA and SOFA wind region height distribution map, and D is the above region height distribution map of SOFA wind;
Figure 18 is under different CCOFA and SOFA wind ratio, the NO of furnace outlet
xconcentration.
Detailed description of the invention
The present invention is described in detail below in conjunction with the drawings and specific embodiments.
In the present embodiment, using the following boiler through transformation as analog computation object, implement the acquisition methods of combustion characteristics under different CCOFA wind and SOFA wind ratio after boiler improvement.
This boiler is 660MW, and subcritical pressure boiler, single reheat, single drum, controlled circulation, coner firing double-tangential firing coal-burning boiler, boiler body as shown in Figure 1.Adopt outdoor layout, boiler is ABB-CE Products.Burning pulverized coal preparation system is that medium-speed pulverizer is direct-firing, and adopt single flow wide regulating ratio tilting burner, burner cross section as shown in Figure 2.4 direct current tilting burners arrange boiler corner by tangential firing mode.Burner divides 6 layers, and 4 First air (breeze airflow) nozzles that often together grate firing burns are connected with same coal pulverizer, for powder, throwing then with throwing, stops, with stopping.6 coal pulverizers form essentially independent 6 powder process subsystems separately, and corresponding with 6 grate firing burner First air nozzles, and 5 layers are put into operation and can meet the needs of boiler maximum continuous rating (MCR).
4 groups of burners are arranged in lower portion thereof four corner cut places, and form typical tangential firing mode, burner total height is 11.266m, and burner axis and the forward and backward wall angle of boiler are respectively 43 ° and 35 ° of angles.As shown in Figure 3, often organize burner and arrange 2 compact burnout degree nozzles (CCOFA) in top in the height direction, the overfire air jet (AA, AB, BC, CD, DE, EF and FF) of 6 First air nozzles (A, B, C, D, E and F) and 7 supply fuel combustion air, and surrounding air nozzle is set around First air nozzle, First air nozzle and overfire air jet are the interval layout of equal distribution wind mode.Wherein, First air nozzle is used to pulverized coal conveying and enters hearth combustion, and what spray into is coal dust and air mixture; Overfire air jet is used to the oxygen amount of supplementary later stage coal dust firing needs, and what spray into is pure air; Compact burnout degree nozzle is used to the oxygen that supplementary after burning needs, and what spray into is pure air.The main purpose arranging surrounding air prevents First air nozzle scaling loss, plays the effect of cooling jet, and another one object is the rigidity strengthening First air injection stream.Various nozzle can swing up and down, and it swings limited range: compact burnout degree nozzle is-5 ° ~ 30 °; Overfire air jet is-30 ° ~ 30 °; First air nozzle is-20 ° ~ 20 °.
Boiler height about 57m, and boiler cross section is rectangle, wide 16.44m, dark 19.558m, as shown in Figure 1.Fig. 2 is burner cross-sectional view.Have 6 layers of First air, 7 layers of Secondary Air and 2 layers of compact burnout degree (CCOFA), as shown in Figure 3.
Pulverized coal preparation system is unit pulverized-coal system, totally 6 layers of mill, and 5 fortune 1 are standby.In this simulation, the superiors' mill is stopped transport.After transformation, 4 install in the level mode of liquidating separation burnout degree (SOFA), and as shown in Figure 4, to reduce emission of NOx of boiler further, the nozzle arrangements of this separation burnout degree as shown in Figure 5.After transformation, because total blast volume does not change, and in Secondary Air, a part is assigned to SOFA wind, and overfire air jet is transformed, and area diminishes, but changes to some extent except the height of the superiors CCOFA, and all the other overfire air jet height all do not change.After transformation in SOFA aperture 100% situation, SOFA wind and CCOFA wind account for 37.2% of total Secondary Air, and only SOFA wind is just 26.8%, with the 20.4%(only CCOFA before transformation) be greatly improved.
The acquisition methods of combustion characteristics under different CCOFA wind and SOFA wind ratio after above-mentioned boiler improvement, comprises the following steps:
1, the structured grid model of boiler is set up.
The design feature of the corner tangential firing formula boiler of SOFA wind is added according to transformation, adopt the method for independent grid division, boiler is divided into 4 regions, is respectively: furnace hopper region, burner region, burner upper area and pendant superheater region, as shown in Figure 6.In the process divided, model all adopts structured grid, in order to improve the precision of calculating, burner region is suitably encrypted, as shown in Figure 7, and the joint face of burner outlet and boiler is set to interface, prevent the mesh quality in two faces and mesh shape from differing greatly and causing error.In the present embodiment, the total lattice number of numerical simulation is about 1,620,000.
In order to verify in the present embodiment, whether grid precision meets calculation requirement, carry out the inspection of grid independence.Adopt 3 kinds of different grid resolution, calculate same operating mode, give assay, as shown in table 1 below.
Table 1 grid independence is checked
As can be drawn from Table 1,1620000 grids (the present embodiment grid used) number model result and 2,000,000 grids (grid precision is higher) obtain result closely, boiler export temperature difference 1.7K, and 1,620,000 grids are compared with 1,200,000 grid results, boiler export temperature difference 24K, therefore can draw, adopt 1,200,000 grid computings to obtain result ratio of precision poor, show that the 1620000 grid scales that the present embodiment adopts meet computational accuracy requirement according to grid independence comparing result.
2, the burner parameter of described boiler, boundary condition parameter and coal dust parameter is obtained;
Described boundary condition comprises the entrance boundary condition of centre wind, First air, Secondary Air, CCOFA wind, SOFA wind and surrounding air in boiler, the export boundary condition of the centre wind in boiler, First air, Secondary Air, CCOFA wind, SOFA wind and surrounding air, boiler wall boundary condition, heat exchange boundary condition;
The entrance boundary condition of the centre wind in described boiler, First air, Secondary Air, CCOFA wind, SOFA wind and surrounding air all adopts quality entrance boundary condition, this quality entrance boundary conditional parameter comprises mass flow, wind-warm syndrome parameter, all set according to design parameter, wherein the quality entrance boundary conditional parameter of CCOFA wind, SOFA wind and surrounding air also calculates according to the working condition changing CCOFA wind and SOFA wind ratio;
The export boundary condition of the centre wind in described boiler, First air, Secondary Air, CCOFA wind, SOFA wind and surrounding air all adopts pressure export boundary condition, and in the present embodiment, pressure is set to-80Pa;
Described boiler wall boundary condition adopts standard law of wall equation, without slip boundary condition;
Described heat exchange boundary condition adopts second kind boundary condition (i.e. temperature boundary condition), and given default wall surface temperature and radiance, wherein, in the present embodiment, given wall surface temperature is 690K, and Wall Radiation rate is 0.8.
Described coal dust parameter comprises coal particle size, coal content and content, and described coal particle size sets according to Rosin-Rammler location mode.Rosin-Rammler distribution supposition is at particle diameter d and the mass fraction Y of particle being greater than this diameter
dbetween there is exponential relationship:
for average diameter, n is profile exponent.
In the present embodiment, minimum grain size 5 μm, maximum particle diameter 250 μm, average grain diameter 60 μm, profile exponent 1.5, so, the relation between quality of pc degree and coal particle size sees the following form 2.
The relation of table 2 quality of pc content and particle diameter
3, founding mathematical models carries out combustion simulation calculating.
According to above-mentioned gridding structural model, burner parameter, boundary condition parameter and coal dust parameter, gas-phase turbulent flow model is obtained with standard k-ε turbulence model simulation, with Hybrid analysis/probability density (ProbabilityDensityFunction, PDF) function model simulation obtains component transport and combustion model, pure coal combustion model is obtained with the simulation of unit fraction/probability density (PDF) function model, obtain mud with two mark/probability density (PDF) function model simulation and mix burning combustion model, pulverized coal particle motion model is obtained with stochastic particle tracking model simulation, the devolatilization model of coal is obtained with the parallel competitive reaction modeling of both sides' journey, coke combustion model is obtained with power/diffusion controlled reaction Rate Models simulation, radiation heat-transfer model is obtained with the simulation of P1 radiation patterns, discrete method all adopts single order upstreame scheme.
Described analog computation calculates with iterative method, first carries out cold conditions and calculates the flow field obtaining certain degree of convergence, and then carry out hot calculating, until convergence.For pressure and the speed coupling employing SIMPLE Algorithm for Solving of discrete equation group, solving equation adopts by-line iterative method and the underrelaxation factor, makes the calculating residual error of NO and HCN parameter be less than 10
-8, the calculating residual error of all the other parameters is less than 10
-6.
Carry out combustion simulation calculating according to the method described above, in order to verify numerical simulation result accuracy, adopt infrared thermography method, boiler export temperature when obtaining on-the-spot actual oepration at full load, and the boiler export NOx concentration that measurement obtains (is converted to 6% oxygen amount, under standard state), comparing result is as shown in table 4 below.
The Data Comparison table of table 4 analog result and actual measured results
Can be found out by Data Comparison, in analog result, boiler export temperature and in-site measurement error range are within 10%, and NOx concentration and on-the-spot relative error are being 1.7%, illustrate that the method analog result of the present embodiment is comparatively accurate.
4, the combustion characteristics of boiler under different CCOFA wind and SOFA wind ratio is obtained.
Utilize above-mentioned Mathematical Modeling, change the ratio of CCOFA wind and SOFA wind, in the present embodiment, physical simulation 5 operating modes, CCOFA and SOFA wind total amount is remained unchanged, for 176kg/s, change CCOFA and SOFA wind ratio, CCOFA and SOFA wind proportioning is respectively: 32-144kg/s, 40-136kg/s, 48-128kg/s, 56-120kg/s, 64-112kg/s.Table 5 is under different CCOFA and SOFA wind ratio, each tuyere air volume proportioning situation.
Parameter list under different CCOFA and the SOFA ratio of table 5
After changing CCOFA and SOFA wind ratio according to upper table 5, by analog computation, obtain the combustion characteristics of boiler under different CCOFA wind and SOFA wind ratio.Specific as follows:
4.1 thermo parameters method situations
4.1.1 undermost Secondary Air Temperature Distribution
Fig. 8 is the rule that this method simulates undermost Secondary Air Temperature Distribution under different CCOFA and the SOFA wind proportionings obtained, and in figure, different colours represents different temperature, specifically sees legend E, and Tu Zhong numerical value unit is K.
As can be seen from Figure 8, by changing CCOFA and SOFA wind ratio, simulation obtains temperature distribution uniform, and the circle of contact is formed relatively good, and do not occur that flame pastes wall phenomenon, wall-cooling surface temperature is lower.
4.1.2 undermost First air Temperature Distribution
Fig. 9 is the rule that this method simulates undermost First air Temperature Distribution under different CCOFA and the SOFA wind proportionings obtained, and wherein in figure, different colours represents that the legend of different temperatures is as Fig. 8 (F).
As can be seen from Figure 9, by changing CCOFA and SOFA wind ratio, simulation obtains temperature distribution uniform, and the circle of contact is formed relatively good, and do not occur that flame pastes wall phenomenon, wall-cooling surface temperature is lower.
4.1.3 boiler center vertical cross-section Temperature Distribution
Figure 10 is the rule that this method simulates boiler center vertical cross-section Temperature Distribution under different CCOFA and the SOFA wind proportionings obtained, and wherein in figure, different colours represents that the legend of different temperatures is as Fig. 8 (F).
As can be seen from Figure 10, burner region temperature is higher, and maximum temperature reaches 2000K, and along flow of flue gas direction, temperature reduces gradually.The simulation of the present embodiment considers pendant superheater to be affected flue-gas temperature, finds out from analog result, and flue gas is through pendant superheater region, and temperature has larger reduction.
4.1.4 boiler lateral cross section mean temperature is along the distribution in boiler height direction
Figure 11 is that this method to simulate under different CCOFA and the SOFA wind proportionings obtained boiler lateral cross section mean temperature along the regularity of distribution in furnace height direction.
Wherein, Figure 11 (A) for Temperature Distribution on whole boiler height direction, Figure 11 (B) be burner region Temperature Distribution, Figure 11 (C) is regional temperature distribution between CCOFA and SOFA wind, and Figure 11 (D) is the distribution of SOFA wind above regional temperature.As can be drawn from Figure 11, change CCOFA and SOFA air flow rate proportioning, to burner region and region between CCOFA nozzle and SOFA nozzle, Temperature Distribution impact is larger, and in the above region of SOFA wind, Temperature Distribution affects smaller.At burner region, when CCOFA and SOFA wind proportioning is 64-112kg/s, it is the highest that burner region temperature compares other proportioning operating mode, and combustion zone maximum temperature is 1741.44K, and maximum temperature position appears at the position of layer 7 overfire air jet.When CCOFA wind and SOFA wind proportioning are 32-144kg/s, 40-136kg/s, in stove, maximum temperature is respectively 1722.4K, 1713.4K, all appears at the position (26m) between CCOFA and SOFA wind nozzle; When CCOFA wind and SOFA wind proportioning are 48-128kg/s, 56-120kg/s, 64-112kg/s, in stove, maximum temperature is respectively 1702.5K, 1696.0K, 1741.4K, all appears at the position of the 7th layer of overfire air jet.Region between CCOFA and SOFA wind, under different ratio, Temperature Distribution impact is larger.
4.1.5 boiler export cigarette temperature
Figure 12 exports cigarette temperature situation of change under this method simulates different CCOFA and the SOFA wind proportionings obtained.
As can be seen from Figure 12, in 5 kinds of different air distribution modes, when CCOFA wind and SOFA wind proportioning are respectively: when 32-144kg/s, 40-136kg/s, 48-128kg/s, 56-120kg/s, 64-112kg/s, furnace exit temperature is respectively: 1523.0K, 1526.5K, 1515.9K, 1511.1K, 1537.2K; When CCOFA and SOFA wind is joined for 64-112kg/s, furnace exit temperature is the highest, is 1537.2K; When CCOFA and SOFA wind proportioning is 56-120kg/s, furnace exit temperature is minimum, is 1511.1K.
4.2 velocity field distribution situations
4.2.1 undermost Secondary Air VELOCITY DISTRIBUTION
Figure 13 is the rule that this method simulates undermost Secondary Air VELOCITY DISTRIBUTION under different CCOFA and the SOFA wind proportionings obtained, and in figure, different colours represents different speed, and specifically see legend in Figure 13 (A), Tu Zhong numerical value unit is m/s.
As can be drawn from Figure 13, under different CCOFA and SOFA wind distributes, the orlop Secondary Air speed circle of contact is formed relatively good, does not occur that speed rushes wall phenomenon.
4.2.2 undermost First air VELOCITY DISTRIBUTION
Figure 14 is the rule that this method simulates undermost First air VELOCITY DISTRIBUTION under different CCOFA and the SOFA wind proportionings obtained, and in figure, different colours represents different speed, specifically sees legend in Figure 13 (A).
As can be drawn from Figure 14, under different CCOFA and SOFA wind distributes, the orlop First air speed circle of contact is formed relatively good, does not occur that speed rushes wall phenomenon.
4.3 component field distribution situation
4.3.1O
2concentration is along the distribution in furnace height direction
Figure 15 is O
2concentration is along furnace height directional spreding.As can be drawn from Figure 15, at 24m with lower area (CCOFA air port is with upper/lower positions), when changing SOFA wind and CCOFA wind ratio, O
2concentration is overlap substantially along boiler height direction, and presents comparatively complicated rule, illustrates and changes CCOFA and SOFA wind proportioning, to O
2distribution influence is smaller; In more than 24m region (between CCOFA wind and SOFA air port), change SOFA wind and CCOFA air quantity ratio, because air distribution mode changes, combustion characteristics changes, O
2there is larger change in CONCENTRATION DISTRIBUTION, and presents comparatively complicated rule; In the above region of SOFA wind snout, along short transverse, O
2concentration reduces gradually, and this is that oxygen amount consumes gradually because later stage unburnt coke burns away.
4.3.2CO concentration is along the distribution in furnace height direction
Figure 16 is that CO concentration is along furnace height directional spreding.With O
2the regularity of distribution is similar, changes SOFA wind and CCOFA wind ratio, and burner region CO concentration profile is overlap substantially; Region between CCOFA wind and SOFA wind, CO concentration profile trend is consistent, and namely along short transverse, CO concentration reduces gradually; In the above position of SOFA wind snout, CO CONCENTRATION DISTRIBUTION trend is substantially similar, and along with highly increasing, CO concentration reduces gradually.
4.3.3NOX concentration is along the distribution in furnace height direction
Figure 17 is that NOx concentration is along furnace height directional spreding.As can be drawn from Figure 17, at burner region, see on the whole, along short transverse, NOx concentration reduces gradually; Region between CCOFA and SOFA wind, along with SOFA air quantity increases, NOx concentration increases, and when CCOFA and SOFA proportioning is 32-144kg/s, NOx concentration reaches peak.Under same CCOFA and SOFA wind proportioning, along short transverse, NOx concentration distribution is comparatively mild; In the above region of SOFA wind snout, between the NOx concentration regularity of distribution and CCOFA and SOFA wind, Regional Laws is similar, when CCOFA and SOFA proportioning is 32-144kg/s, NOx concentration reaches peak, under different CCOFA and SOFA wind proportioning, along short transverse, NOx concentration has increase to a certain degree.
4.3.4 the NOX concentration of boiler export
Figure 18 is for calculating different SOFA wind aperture lower hearth exit NOx concentration Changing Pattern.As can be drawn from Figure 18, along with SOFA air quantity reduces, furnace outlet NOx concentration reduces gradually, and when CCOFA and SOFA wind proportioning is 64-112kg/s, it is 221.75mg/Nm that furnace outlet NOx concentration reaches minimum of a value
3; When CCOFA and SOFA wind proportioning is 32-144kg/s, it is 247.76mg/Nm that furnace outlet NOx concentration reaches peak
3.
Above-mentioned for certain power plant 660MW ultra supercritical swirl flow combustion pulverized-coal fired boiler, simulate under becoming CCOFA wind and SOFA wind, the rule of stove Combustion Characteristics change.Result and the on-site actual situations of simulation are coincide relatively good, and demonstrate the validity of numerical simulation result herein, Main Conclusions is as follows:
(1) numerical simulation result furnace exit temperature and in-site measurement error range are within 10%, and NOx concentration and on-the-spot relative error are being 1.7%, illustrate that numerical simulation result is comparatively accurate herein;
(2) after adopting the transformation of low nitrogen to increase SOFA wind, different CCOFA wind with under SOFA wind, fire box temperature distribution uniform, the circle of contact is formed relatively good, and do not occur flame subsides wall phenomenon, wall-cooling surface temperature is lower; Under different CCOFA wind and SOFA wind, the orlop Secondary Air speed circle of contact is formed relatively good, does not occur that speed rushes wall phenomenon.
(3) in stove, maximum temperature appears at CCOFA wind and SOFA wind proportioning is 64-112kg/s, except CCOFA wind and SOFA wind proportioning are 32-144kg/s, 40-136kg/s, maximum temperature appears at the position (26m) between CCOFA wind and SOFA wind snout, in other proportioning situation, maximum temperature all appears at the 7th layer of overfire air port position (24m).
(4) when CCOFA and SOFA wind is joined for 64-112kg/s, furnace exit temperature is the highest, is 1537.2K; When CCOFA and SOFA wind proportioning is 56-120kg/s, furnace exit temperature is minimum, is 1511.1K.
(5) at burner region, see on the whole, along short transverse, NOx concentration reduces gradually; Region between CCOFA and SOFA wind and more than SOFA wind snout, along with SOFA air quantity increases, NOx concentration increases.
(6) along with SOFA air quantity reduces, furnace outlet NOx concentration reduces gradually, and when CCOFA and SOFA wind proportioning is 64-112kg/s, it is 221.75mg/Nm that furnace outlet NOx concentration reaches minimum of a value
3; When CCOFA and SOFA wind proportioning is 32-144kg/s, it is 247.76mg/Nm that furnace outlet NOx concentration reaches peak
3.
Shown by the research of the present embodiment, adopt after increasing the low nitrogen transformation of SOFA wind, in stove, velocity field, temperature field are formed relatively good, do not occur rushing wall phenomenon, and actual motion shows that low nitrogen modification measures is effective.In the present embodiment under different CCOFA wind and SOFA wind proportioning, the rule of velocity field in stove, temperature field, component field and pollutant field distribution, for actual motion provides theoretic guidance, has important construction value.
The above embodiment only have expressed several embodiment of the present invention, and it describes comparatively concrete and detailed, but therefore can not be interpreted as the restriction to the scope of the claims of the present invention.It should be pointed out that for the person of ordinary skill of the art, without departing from the inventive concept of the premise, can also make some distortion and improvement, these all belong to protection scope of the present invention.Therefore, the protection domain of patent of the present invention should be as the criterion with claims.
Claims (9)
1. the acquisition methods of combustion characteristics under different CCOFA wind and SOFA wind ratio after boiler improvement, is characterized in that, comprise the following steps:
According to the design feature of corner tangential firing formula boiler, described boiler is carried out stress and strain model, set up the gridding structural model of this boiler; The structure of described boiler is be provided with CCOFA wind nozzle often organizing above burner, and above CCOFA wind nozzle, be provided with the SOFA wind nozzle installed in the level mode of liquidating;
Obtain the burner parameter of described boiler, boundary condition parameter and coal dust parameter;
According to above-mentioned gridding structural model, burner parameter, boundary condition parameter and coal dust parameter, gas-phase turbulent flow model is obtained with standard k-ε turbulence model simulation, component transport and combustion model is obtained with Hybrid analysis/probability density estimation simulation, pure coal combustion model is obtained with unit fraction/probability density estimation simulation, obtain mud mix burning combustion model with two mark/probability density estimation simulation, pulverized coal particle motion model is obtained with stochastic particle tracking model simulation, the devolatilization model of coal is obtained with the parallel competitive reaction modeling of both sides' journey, coke combustion model is obtained with power/diffusion controlled reaction Rate Models simulation, radiation heat-transfer model is obtained with the simulation of P1 radiation patterns,
Utilize above-mentioned model, change the ratio of CCOFA wind and SOFA wind, by analog computation, obtain the combustion characteristics of boiler under different CCOFA wind and SOFA wind ratio.
2. the acquisition methods of combustion characteristics under different CCOFA wind and SOFA wind ratio after boiler improvement according to claim 1, it is characterized in that, the concrete steps that described boiler carries out stress and strain model are comprised: in the mode of independent grid division, this boiler is divided into furnace hopper region, burner region, burner upper area and pendant superheater region.
3. the acquisition methods of combustion characteristics under different CCOFA wind and SOFA wind ratio after boiler improvement according to claim 2, it is characterized in that, described concrete steps of boiler being carried out stress and strain model comprise: be encrypted by burner region, and the joint face of burner outlet and boiler is set to interface.
4. the acquisition methods of combustion characteristics under different CCOFA wind and SOFA wind ratio after boiler improvement according to claim 3, it is characterized in that, after setting up the gridding structural model of described boiler, carry out the inspection of grid independence with the grid of different accuracy, choose the grid precision meeting computational accuracy and require.
5. the acquisition methods of combustion characteristics under different CCOFA wind and SOFA wind ratio after boiler improvement according to claim 1, it is characterized in that, described boundary condition comprises the entrance boundary condition of centre wind, First air, Secondary Air, CCOFA wind, SOFA wind and surrounding air in boiler, the export boundary condition of the centre wind in boiler, First air, Secondary Air, CCOFA wind, SOFA wind and surrounding air, boiler wall boundary condition, heat exchange boundary condition;
The entrance boundary condition of the centre wind in described boiler, First air, Secondary Air, CCOFA wind, SOFA wind and surrounding air all adopts quality entrance boundary condition, this quality entrance boundary conditional parameter comprises mass flow, wind-warm syndrome parameter, and all set according to design parameter, wherein the quality entrance boundary conditional parameter of CCOFA wind, SOFA wind and surrounding air also calculates according to the working condition changing CCOFA wind and SOFA wind ratio;
The export boundary condition of the centre wind in described boiler, First air, Secondary Air, CCOFA wind, SOFA wind and surrounding air all adopts pressure export boundary condition;
Described boiler wall boundary condition adopts standard law of wall equation, without slip boundary condition;
Described heat exchange boundary condition adopts second kind boundary condition, given default wall surface temperature and radiance.
6. the acquisition methods of combustion characteristics under different CCOFA wind and SOFA wind ratio after boiler improvement according to claim 1, it is characterized in that, described coal dust parameter comprises coal particle size, coal content and content, and described coal particle size sets according to Rosin-Rammler location mode.
7. the acquisition methods of combustion characteristics under different CCOFA wind and SOFA wind ratio after boiler improvement according to claim 1, it is characterized in that, described analog computation calculates with iterative method, first carry out cold conditions and calculate the flow field obtaining certain degree of convergence, and then carry out hot calculating, until convergence; Be specially:
For pressure and the speed coupling employing SIMPLE Algorithm for Solving of discrete equation group, solving equation adopts by-line iterative method and the underrelaxation factor, makes the calculating residual error of NO and HCN parameter be less than 10
-8, the calculating residual error of all the other parameters is less than 10
-6.
8. the acquisition methods of combustion characteristics under different CCOFA wind and SOFA wind ratio after boiler improvement according to claim 1, it is characterized in that, the combustion characteristics of described boiler comprises thermo parameters method situation, velocity field distribution situation and component field distribution situation.
9. the acquisition methods of combustion characteristics under different CCOFA wind and SOFA wind ratio after boiler improvement according to claim 8, it is characterized in that, described thermo parameters method situation comprises: undermost Secondary Air Temperature Distribution, undermost First air Temperature Distribution, boiler center vertical cross-section Temperature Distribution, the distribution of boiler lateral cross section mean temperature along furnace height direction and the cigarette temperature of furnace outlet; Described velocity field distribution situation comprises: undermost Secondary Air VELOCITY DISTRIBUTION and orlop First air VELOCITY DISTRIBUTION; Described component field distribution situation comprises: O
2concentration is along the distribution in furnace height direction, CO concentration along the distribution in furnace height direction, NO
xthe distribution of concentration along furnace height direction and the NO of furnace outlet
xconcentration.
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Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2007085682A (en) * | 2005-09-26 | 2007-04-05 | Babcock Hitachi Kk | Boiler for thermal power generation, and combustion air supply control method |
| CN101832541A (en) * | 2010-05-14 | 2010-09-15 | 上海发电设备成套设计研究院 | Method for self-searching optimal thermal deviation working condition of boiler superheter and reheater of power station |
| CN102692013A (en) * | 2012-05-15 | 2012-09-26 | 上海锅炉厂有限公司 | Tangential firing system under air staged combustion technology |
| CN103235842A (en) * | 2013-03-29 | 2013-08-07 | 广东电网公司电力科学研究院 | Acquisition method and system for burning behaviors of tangential firing boiler |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US7865271B2 (en) * | 2006-11-02 | 2011-01-04 | General Electric Company | Methods and systems to increase efficiency and reduce fouling in coal-fired power plants |
-
2014
- 2014-03-28 CN CN201410126277.9A patent/CN103968412B/en active Active
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2007085682A (en) * | 2005-09-26 | 2007-04-05 | Babcock Hitachi Kk | Boiler for thermal power generation, and combustion air supply control method |
| CN101832541A (en) * | 2010-05-14 | 2010-09-15 | 上海发电设备成套设计研究院 | Method for self-searching optimal thermal deviation working condition of boiler superheter and reheater of power station |
| CN102692013A (en) * | 2012-05-15 | 2012-09-26 | 上海锅炉厂有限公司 | Tangential firing system under air staged combustion technology |
| CN103235842A (en) * | 2013-03-29 | 2013-08-07 | 广东电网公司电力科学研究院 | Acquisition method and system for burning behaviors of tangential firing boiler |
Non-Patent Citations (3)
| Title |
|---|
| "变风速下四角切圆锅炉燃烧特性的数值模拟";李德波等;《动力工程学报》;20130331;第33卷(第3期);全文 * |
| "大型电站锅炉数值模拟技术工程应用进展与展望";李德波等;《广东电力》;20131130;第26卷(第11期);全文 * |
| "某３0０ＭＷ机组锅炉ＮＯｘ排放特性数值模拟"";童家麟等;《热力发电》;20130630;第42卷(第6期);全文 * |
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Address after: 510080 Dongfeng East Road, Dongfeng, Guangdong, Guangzhou, Zhejiang Province, No. 8 Patentee after: ELECTRIC POWER RESEARCH INSTITUTE, GUANGDONG POWER GRID CO., LTD. Address before: 510080 Dongfeng East Road, Dongfeng, Guangdong, Guangzhou, Zhejiang Province, No. 8 Patentee before: Electrical Power Research Institute of Guangdong Power Grid Corporation |