CN104896506B - Building method for combustion energy radiant energy signal in coal-fired thermal power generating unit boiler - Google Patents

Abstract

The invention discloses a building method for a combustion energy radiant energy signal in a coal-fired thermal power generating unit boiler and belongs to the technical field of thermal power plant boiler combustion monitoring and control. Firstly, image information of combustion flame is obtained through a plurality of flame image detectors arranged on different height positions along a boiler chamber, the grey value of each image is calculated in real time and transformed into a measuring range same as the thermal power generating unit actual generated power and defined as an initial radiant energy signal. Secondly, dynamic compensation data processing is performed on the initial radiant energy signal by the use of the value of the thermal power generating unit actual generated power, and the final radiant energy signal is obtained. Finally, the final radiant energy signal serves as a detection value of energy level in the boiler to be output to a coordinated control system of the thermal power generating unit. The application result shows that the radiant energy signal built by the method can effectively reflect the pulsatility of flame in the boiler chamber, the signal deviation caused by detector ash deposition and coking and other factors is eliminated, and the building method can be suitable for continuous on-line optimal control of thermal power generating units with different types and different capacities.

Description

The construction method of burning capacity radiant energy signal in a kind of fossil-fired unit stove

Technical field

The present invention relates in a kind of fossil-fired unit stove burning capacity radiant energy signal construction method, belong to firepower send out Boiler of power plant combustion monitoring and control technology.

Background technology

Radiant energy signal is obtained using furnace flame radiant image monitoring system, stove combustion process release energy is accurately reflected Amount on-line monitoring technique (Zhou Huaichun, furnace flame Visual retrieval philosophy and technique, Science Press, in May, 2005, Pp.306-309) certain achievement is obtained in fired power generating unit coordination optimization control field.

The technology be by installing many thermal-flame image detectors on pulverized coal firing boiler differing heights, position, Flame Image is shot, Jing image processing techniquess, radiant heat transfer are theoretical and advanced solution strategies obtain radiant energy signal.Due to Flame color image brightness is directly proportional to the radiation energy that image detector is received, and fixes in image acquisition and treatment conditions In the case of (lens aperture, photography shutter, gain and white balance etc. affect image information condition do not change), can be direct Relative radiation energy signal is obtained from the gray value of image, radiant energy signal initial value can be referred to as.The value can be quickly anti- Furnace cavity combustion position is reflected, it is strong with the relatedness of unit, but detector is in use by coking, dust stratification, eyeglass discoloration Deng impact, prompt radiation energy signal value occurs unstable, the big, situation of poor reliability of pulsing.On this basis, Chinese patent Document discloses a kind of method of amendment radiation energy static deviation【Application number：201310301791.7】, describe a kind of concrete Solution, impact of each factor to radiant energy signal accuracy is eliminated to a certain extent.

In order to the optimization improved to prompt radiation energy is calculated, different type, the unit of various capacity, and Jing are preferably adapted to Long-term application to engineering practice, it is proposed that a kind of newest radiant energy signal detection and construction method.

The content of the invention

The purpose of the present invention is to propose to burning capacity radiant energy signal construction method in a kind of fossil-fired unit stove so as to The radiant energy signal of acquisition have accuracy height, strong applicability, it is interference-free the features such as.

Technical scheme is as follows：

A kind of construction method of burning capacity radiant energy signal in fossil-fired unit stove, its feature includes as follows in method Step：

1), many flame image detectors are installed along burner hearth differing heights position, furnace flame radiation image letter is obtained Breath, Jing image processing techniquess calculate in real time the gray value GSU of image_i,j, its expression formula:

GSU_i,j=0.11R+0.59G+0.23B (1)

Wherein, i is the number of flame detector, and j is the number that each detector gathers image, and every image is calculated One gray value；R, G, B are respectively the image three primary colories red, green, blue value of information, and define the gray value GSU of image_i,jFor initial Radiation energy；

2), sending out power using the reality of unit can do dynamic range conversion to prompt radiation as benchmark, according to formula (2-3):

E_i,M=k_1,i·GSU_i,M (3)

Wherein, k_1,iFor the proportionality coefficient of the prompt radiation energy signal of i-th detector acquisition, M is to calculate proportionality coefficient Data segment, length, P_jPower, GSU are sent out in fact for the unit in the data segment_i,MPrompt radiation for i-th detector acquisition can be believed Number the M moment numerical value, E_i,MThe as M moment is converted to the radiation energy value with unit load with range；

3), screening wherein correctly reflects the prompt radiation energy signal of unit load change, according to formula (4-5):

|E_i,M-P_M|≤E_thr (4)

Wherein, P_MReality for the correspondence M moment sends out power, E_thrFor the threshold value of setting, N is total detector number, and N ' is satisfaction The detector number of formula (4), E₀The radiant energy signal average of the correct reflection energy variation after as screening；

4), to unit load variations acute phase radiant energy signal average E₀Optimization：

E=k₂·E₀ (7)

Wherein, k₂For second correction factor, a', b' are k_1,iThe average of random group changed power is with generated output P Jing most The calculated coefficient of little square law,For generated output average, E is reacting furnace energy levels height, finally exports Radiation energy.

The present invention compared with relevant art, the technique effect with advantages below and salience：

The present invention has mainly used the link of proportionality coefficient amendment twice and a threshold decision link, first time ratio to repair Exactly the gray value of image, i.e. prompt radiation can be worth to be transformed into and send out power identical range in fact with unit；Threshold decision link It is to reject affecting for error message because being subject to the factor such as coking, dust stratification to be brought in the running of image detector.Second Secondary ratio amendment is to eliminate violent varying duty stage radiation energy according to the linear relationship of first correction factor and the power of the assembling unit The excessive or too small deviation of signal；The radiant energy signal for finally giving is the detection signal of capacity of furnace level, in burning instruction Radiant energy signal can be reflected timely when changing, otherwise its value it is excessive or it is too small reflect combustion rate in stove " supply More than asking ", or " supply-less-than-demand ", and the radiant energy signal that the method builds is by measurement effect of noise, and can conduct The operational factor of unit is transported in coordinated control system and participates in combustion control.

Jing practice results prove that the radiant energy signal of output can either effectively reflect the pulsating nature of furnace flame, eliminate again Deviation of signal caused by detector dust deposition, can be applied to different model, the coal unit of different capabilities.To participating in Boiler combustion and the optimal control of unit cooperative provide a good on-line checking means.

Description of the drawings

Fig. 1 is flame on-line monitoring system structure chart.

Fig. 2 is radiant energy signal construction method flow chart.

Fig. 3 sends out power contrast's curve for the gray value of image with real.

Fig. 4 is that detector C CD13 obtains image intensity value and real power contrast, it can be found that 9:10 and 9:40 moment There is larger error message.

Fig. 5 is the judgement of primary radiation energy signal threshold value, per layer in 4 layers of flame detector of representative is given, by threshold value Bound rejects error value.

Fig. 6 is the primary radiation energy signal average after threshold decision, and the source number for calculating the average is dynamic, with machine Group actual generation power contrast, it can be seen that both difference.

Fig. 7 a, Fig. 7 b are the prompt radiation energy signal errors in lifting load stage, less than normal, bigger than normal that circle mark is used in figure Go out.

Fig. 8 a, Fig. 8 b are that final radiant energy signal and unit send out in fact power contrast.

Fig. 9 a, Fig. 9 b and Fig. 9 c are respectively the application of the radiation energy detecting system in 200MW, 300MW, 600WM boiler, most Eventually the radiant energy signal of output sends out correlation curve of the power at one day with real.

Specific embodiment

With reference to the accompanying drawings and examples the present invention is described further.

Burning capacity radiant energy signal construction method in a kind of fossil-fired unit stove that the present invention is provided, its specific reality Existing method is as follows：

First, the flame detector on differing heights position in coal-burning boiler burner hearth 1 obtains the Fire Radiation in stove Image information, and be sent in DVR by video acquisition system 2 and synthesize a sub-picture 3, Jing image processing techniquess are real-time The rgb value of image is calculated, asks it to represent the gray value GSU (gray-scale-unit) of relative radiation energy signal, such as expression formula：

GSU_i,j=0.11R+0.59G+0.23B (1)

Wherein, i is the number of flame detector, and j is the number that each detector gathers image, and every image is calculated One gray value.

2nd, furnace radiant energy signal is that fuel reflects that it is by radiant heat transfer, to spreading in the energy that hearth combustion discharges The modes such as heat are delivered in boiler circuit, and are ultimately converted to the output electric energy of electromotor.So, the change of radiation of burner hearth energy is most Cause the change of unit generation amount eventually, radiation of burner hearth can be consistent with the actual power generation change direction of unit.Based on this, with The reality of unit sends out power as benchmark to representing the gray value GSU of radiant energy signal_i,jDynamic tracking calculating is done, according to formula (2)：

k_1,iFor the proportionality coefficient of the prompt radiation energy signal of i-th detector acquisition, M is the data for calculating proportionality coefficient Segment length, P_jPower, GSU are sent out in fact for the unit in the data segment_i,MPrompt radiation energy signal for i-th detector acquisition exists The numerical value at M moment：

E_i,M=k_1,i·GSU_i,M (3)

E_i,MThe radiation energy value with unit generation power with range is converted to for the M moment；

3rd, screening wherein correctly reflect unit load change primary radiation energy signal, method be by with unit generation work( Rate

With the radiant energy signal E of range_i,MPower P is sent out with current reality_MMake mathematic interpolation, such as following formula：

|E_i,M-P_M|≤E_thr (4)

E_thrFor given threshold, P_MReality for the correspondence M moment sends out performance number.It is unsatisfactory for the radiant energy signal explanatory diagram of above formula The error message contained in piece is larger, needs to reject, according to formula (5):

Wherein, N is total detector number, and N ' is to meet the detector number of formula (4), E₀Correct reflection after as screening The radiant energy signal average of energy variation.E_thrSelection should retain can in reacting furnace normal energy fluctuation detector information, Again will be invalid or rejected by the larger detector information of the factors such as coking, play the work of a limit error scope With.It is noted that due to combustion conditions it is different from detector working condition, wherein correctly reflect the capacity of furnace change it is original The quantity N ' of radiant energy signal is also dynamic change.

4th, when unit load changes the single radiant energy signal amendment of acute phase, because radiation energy is by currently surveying Value and correction factor k_1,iProduct obtain.Due to the capability of fast response of radiant energy signal itself, increased by quantity combusted When can increase rapidly, and now the power of the assembling unit is affected by the delay of steam-water heat transfer system, gathers way compared with radiant energy signal Slowly, the correction factor k for now being obtained by both mean value computations_1,iCan be less than normal, cause radiant energy signal average E₀Also can be inclined It is little, in the same manner during unit load down, radiant energy signal average E₀Can be bigger than normal.Therefore second ratio correction coefficient k is introduced₂, setting For k_1,iThe meansigma methodss of random group changed power, useWith the linear relationship Mobile state amendment of unit generation power, such as formula (6-7)：

Wherein, P is current time unit load,For the load average of a period of time.

After the process of the step, the expression formula of final radiant energy signal E is：

E=k₂·E₀ (8)

Embodiment：

The present invention has corresponding software and hardware to support, its concrete implementation method is as follows：

Flame detector on burner hearth differing heights position obtains the flame radiation image information in stove, with 16 4 layers of flame detector point, as a example by 4 per layer are applied on the subcritical boiler of 300MW, its structure is as shown in Figure 1.

The parameter for arranging CCD camera in flame detector first is fixed, it is ensured that image clearly, and the state of saturation is unable to again, SDK2000 video frequency collection cards are driven to complete the collection of flame radiation image.16 road video signals are synthesized into one by DVR Width flame radiation image is transported to computer system.

The step of building radiant energy signal flow process is as shown in Figure 2.The normal flame image brightness that each detector catches The energy that represents space in furnace wall face and the CCD angles of visual field is emitted, absorb, scatter to Net long wave radiation energy up to target surface, because This its value has identical variation tendency with actual generation power, but is affected by detector working environment and state, meeting There is coking, the phenomenon of dust stratification, cause the untrue of image, deviation, example occurs in the image intensity value that radiation energy is represented accordingly Such as detector C CD13 in Fig. 3.Partial enlargement Fig. 4, can clearly have found 9:10 and 9:There is larger ripple in 40 moment Dynamic, this is caused due to detector coking, and after Jiao comes off, image intensity value returns to normal value again.

Using correction factor one, dynamic calculation is carried out to initial gray value, complete and send out power equal amount in fact with unit The process of journey.Given threshold E_thrWhen=30, i.e. primary radiation can be worth the difference with real power more than the threshold value, the corresponding spoke Penetrating energy signal can be disallowable, and the radiation energy being not involved in below is calculated.As shown in figure 5, the intermediate value that Jing threshold values bound judges For normal signal, meet desired primary radiation energy signal and ask it to be worth to radiant energy signal initial value, as shown in Figure 6.

When unit is in varying duty stage running, such as in load up, because radiant energy signal is subject to the sound of quantity combusted increase Answering speed to be faster than unit and send out power in fact causes first correction factor can be less than normal, and radiation energy initial value is less than normal obtained from, together Radiation energy initial value can be bigger than normal during reason unit load down.As shown in circle sign in Fig. 7 a and Fig. 7 b.Correct using under each load Coefficient k_1,iAverageThe linear relationship of the power of the assembling unit, the second correction factor k obtained using formula (7)₂To radiant energy signal Initial value ratio is finely tuned, and notes wherein calculating real power averageTime segment length can be adjusted according to actual effect.Most Afterwards final radiant energy signal E is calculated by formula (8), as a result as figures 8 a and 8 b show.

The radiant energy signal built by the method can correctly reflect the change of burning capacity in stove, its physical significance What is represented is when front furnace internal combustion burns the corresponding relation of thermal discharge and power of the assembling unit energy requirement.The radiation energy calculating side of the present invention Method is applied to all kinds, the unit of various capacity, as shown in Fig. 9 a, Fig. 9 b and Fig. 9 c.Radiant energy signal and unit load two The difference of person reflects firing optimization in stove not to be had in place.The difference for further reducing between the two is optimization boiler turbine The target of therrmodynamic system control, is also that meaning of the present invention is located.

Claims (1)

1. in a kind of fossil-fired unit stove burning capacity radiant energy signal construction method, its feature includes following step in method Suddenly：

1), many flame image detectors are installed along the position of burner hearth differing heights, furnace flame radiation image information is obtained, Jing image processing techniquess calculate in real time the gray value GSU of image_i,j, its expression formula:

GSU_i,j=0.11R+0.59G+0.23B (1)

Wherein, i is the number of flame detector, and j is the number that each detector gathers image, and every image is calculated one Gray value；R, G, B are respectively the image three primary colories red, green, blue value of information, and define the gray value GSU of image_i,jFor prompt radiation Can value；

2), using the reality of unit power prompt radiation can be worth as benchmark and does dynamic range conversion, according to formula (2-3):

$k_{1,i}=\frac{\underset{j=1}{\overset{M}{\Σ}}{P}_j/{\mathrm{GSU}}_{i,j}}{M}---\left(2\right)$

E_i,M=k_1,i·GSU_i,M (3)

Wherein, k_1,iFor the proportionality coefficient of the prompt radiation energy signal of i-th detector acquisition, M is the data for calculating proportionality coefficient Segment length, P_jPower, GSU are sent out in fact for the unit in the data segment_i,MPrompt radiation energy signal for i-th detector acquisition exists The numerical value at M moment, E_i,MThe as M moment is converted to the radiation energy value with unit load with range；

3), screening wherein correctly reflects the prompt radiation energy signal of unit load change, according to formula (4-5):

|E_i,M-P_M|≤E_thr (4)

$\begin{array}{cc}{E}_0=\frac{\underset{i=1}{\overset{N^{\′}}{\Σ}}{E}_{i,M}}{N^{\′}}& (N^{\′}\≤N)\end{array}---\left(5\right)$

Wherein, P_MReality for the correspondence M moment sends out power, E_thrFor the threshold value of setting, N is total detector number, and N ' is to meet formula (4) detector number, E₀The radiant energy signal average of the correct reflection energy variation after as screening；

4), to unit load variations acute phase radiant energy signal average E₀Optimization：

$k_2=(a^{\′}+b^{\′}\·P)/(a^{\′}+b^{\′}\·\stackrel{\‾}{P})---\left(6\right)$

E=k₂·E₀ (7)

Wherein, k₂For second correction factor, a', b' are k_1,iThe average of random group changed power and a generated output P Jing most young waiters in a wineshop or an inn The calculated coefficient of multiplication,For generated output average, E is reacting furnace energy levels height, the radiation for finally exporting Energy.