CN212167066U - Ammonia spraying optimization control system of SCR flue gas denitration device - Google Patents
Ammonia spraying optimization control system of SCR flue gas denitration device Download PDFInfo
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- CN212167066U CN212167066U CN202020509925.XU CN202020509925U CN212167066U CN 212167066 U CN212167066 U CN 212167066U CN 202020509925 U CN202020509925 U CN 202020509925U CN 212167066 U CN212167066 U CN 212167066U
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- QGZKDVFQNNGYKY-UHFFFAOYSA-N Ammonia Chemical compound N QGZKDVFQNNGYKY-UHFFFAOYSA-N 0.000 title claims abstract description 304
- 239000003546 flue gas Substances 0.000 title claims abstract description 180
- UGFAIRIUMAVXCW-UHFFFAOYSA-N Carbon monoxide Chemical compound [O+]#[C-] UGFAIRIUMAVXCW-UHFFFAOYSA-N 0.000 title claims abstract description 179
- 229910021529 ammonia Inorganic materials 0.000 title claims abstract description 152
- 238000005507 spraying Methods 0.000 title claims description 68
- 238000005457 optimization Methods 0.000 title claims description 19
- 238000005070 sampling Methods 0.000 claims abstract description 127
- 238000002347 injection Methods 0.000 claims abstract description 60
- 239000007924 injection Substances 0.000 claims abstract description 60
- 238000004868 gas analysis Methods 0.000 claims abstract description 37
- 239000000126 substance Substances 0.000 claims description 2
- 238000005259 measurement Methods 0.000 abstract description 20
- 238000004364 calculation method Methods 0.000 abstract description 7
- 206010022000 influenza Diseases 0.000 abstract 4
- 238000000034 method Methods 0.000 description 15
- 238000005192 partition Methods 0.000 description 11
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 10
- 239000000523 sample Substances 0.000 description 8
- 238000004458 analytical method Methods 0.000 description 6
- 238000007781 pre-processing Methods 0.000 description 6
- 229910052757 nitrogen Inorganic materials 0.000 description 5
- 239000000428 dust Substances 0.000 description 4
- 238000000605 extraction Methods 0.000 description 4
- 239000000779 smoke Substances 0.000 description 4
- 238000012937 correction Methods 0.000 description 3
- 238000010586 diagram Methods 0.000 description 3
- 230000004069 differentiation Effects 0.000 description 3
- 238000011217 control strategy Methods 0.000 description 2
- 238000001514 detection method Methods 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 238000002474 experimental method Methods 0.000 description 2
- 239000000203 mixture Substances 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 239000000243 solution Substances 0.000 description 2
- 238000000638 solvent extraction Methods 0.000 description 2
- 125000004122 cyclic group Chemical group 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 239000007789 gas Substances 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- 231100001143 noxa Toxicity 0.000 description 1
- 230000008569 process Effects 0.000 description 1
- 230000000750 progressive effect Effects 0.000 description 1
- 239000007921 spray Substances 0.000 description 1
- 238000010977 unit operation Methods 0.000 description 1
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Abstract
The utility model discloses a SCR flue gas denitration device spouts ammonia optimal control system, include a plurality of entry flue gas sampling device, multiunit entry flue gas flow measurement device, entry flue gas analysis and controlling means, entry flue sampling diverter valve door device, a plurality of export flue gas sampling device, export flue gas analysis and controlling means, spout ammonia device, DCS control system. The control system divides the grids of the inlet flues and the outlet flues, corresponds the inlet flues and the outlet flues to each grid one by one, samples each inlet flue grid and each outlet flue grid respectively, samples each corresponding inlet flue grid and outlet flue grid, analyzes and calculates a DCS system, and controls the total ammonia injection amount and each corresponding inlet flue grid area to perform partitioned ammonia injection according to the calculation result, thereby realizing partitioned differential control of ammonia injection, reducing over-injection and under-injection of ammonia, reducing ammonia escape rate, saving energy, reducing consumption and improving unit safety.
Description
Technical Field
The utility model relates to a flue gas denitration technical field especially relates to a SCR flue gas denitration device spouts ammonia optimal control system.
Background
The requirement of people on beautiful environment is gradually improved, and in order to meet the requirement of people on good life, a series of policies and measures are provided by the nation, and the thermal power plant is encouraged to implement ultralow emission reconstruction. In denitration modification, some positive measures are also taken. Firstly, the flow field is further optimized and designedAnd improvement is carried out to ensure the flue gas flow speed and NO of the cross section of the SCR inletxUniformity of concentration distribution. But is influenced by the limitation of site space, and the effect is not high. Then increase of SCR system inlet NOxThe number of concentration measuring probes is changed from one sampling probe to three sampling probes, and the method is used for multi-point mixed sampling of flue gas, but the methods still enable the inlet NO of the SCR systemxThe concentration measurement data are still not representative and cannot measure the actual concentration of the whole flue section. Meanwhile, the ammonia injection control system still adopts an adjusting valve for adjustment, the requirements of different ammonia injection amounts in various areas of the section of the flue cannot be met, the ammonia/nitrogen molar ratio is not uniform, if the ammonia is too large, the ammonia cannot fully participate in the reaction, and the ammonia escape at the outlet of the reactor is increased; when the amount is too small, the amount of sprayed ammonia is insufficient, NOxThe reaction cannot be completely reduced and absorbed, and the emission concentration exceeds the standard. Non-uniformity of the velocity field also has some effect on the ammonia/nitrogen mole ratio and control logic cannot correct it.
SUMMERY OF THE UTILITY MODEL
The utility model aims at solving the defect that exists among the prior art, provide a control system, can spout ammonia control by the subregion, carry out subregion differentiation control and total amount control to spouting ammonia, reach and spout ammonia fine control to at control unit NOxOn the premise of standard emission of the concentration, over-spraying and under-spraying of ammonia are reduced, the ammonia escape rate is reduced, energy is saved, consumption is reduced, and the safety of a unit is improved.
In order to achieve the purpose, the utility model provides an ammonia spraying optimization control system of an SCR flue gas denitration device, which comprises a plurality of inlet flue gas sampling devices, a plurality of groups of inlet flue gas flow measuring devices, an inlet flue gas analyzing and controlling device, an inlet flue sampling switching valve device, a plurality of outlet flue gas sampling devices, an outlet flue gas analyzing and controlling device, an ammonia spraying device and a DCS control system; wherein the content of the first and second substances,
the inlet flue gas sampling devices respectively correspond to each grid area of the section of the inlet flue;
the multiple groups of inlet flue gas flow measuring devices respectively correspond to each grid area of the section of the inlet flue and are connected with the inlet flue gas analysis and control device;
the inlet flue gas analysis and control device is connected with the plurality of inlet flue gas sampling devices through the inlet flue gas sampling switching valve device and is connected with the DCS control system;
the outlet flue gas sampling devices respectively correspond to each grid area of the section of the outlet flue;
the outlet flue gas analysis and control device is connected with the outlet flue gas sampling devices through the outlet flue gas sampling switching valve device and is connected with the DCS control system;
the ammonia spraying device comprises an ammonia spraying main valve, a plurality of ammonia spraying branch pipes and an ammonia spraying branch valve, and the ammonia spraying main valve, the plurality of ammonia spraying branch pipes and the ammonia spraying branch valves respectively correspond to each grid area of the cross section of the inlet flue;
the DCS control system is connected with the ammonia injection main valve and each ammonia injection branch valve in a control mode.
Specifically, the method comprises the following steps:
the plurality of inlet flue gas sampling devices are used for sampling inlet flue gas corresponding to each grid area of the section of the inlet flue;
the multiple sets of inlet flue gas flow measuring devices are used for measuring the gas flow corresponding to each grid area of the section of the inlet flue and sending the measured data to the inlet flue gas analysis and control device;
the inlet flue gas analysis and control device is used for analyzing the sampled flue gas and the flue gas flow measurement data and sending the analysis data to the DCS control system;
the inlet flue sampling switching valve device receives an instruction and selects an inlet flue gas sampling device extracted to the inlet flue gas analysis and control device;
the outlet flue gas sampling devices correspond to all grid areas of the cross section of the outlet flue and correspond to the inlet flue gas sampling devices one by one to sample the outlet flue gas;
the outlet flue gas analysis and control device is used for analyzing the sampled flue gas and sending the analysis data to the DCS control system;
the outlet flue sampling switching valve device receives an instruction and selects an outlet flue gas sampling device extracted to the outlet flue gas analysis and control device;
the ammonia spraying device comprises a plurality of ammonia spraying branch pipes and ammonia spraying branch valves, and the ammonia spraying branch pipes and the ammonia spraying branch valves respectively correspond to each grid area of the cross section of the inlet flue, receive instructions and perform partitioned ammonia spraying;
and the DCS receives data of the inlet flue gas analysis and control device and the outlet flue gas analysis and control device, calculates the total ammonia injection amount and the partitioned ammonia injection amount, and sends an instruction to control the ammonia injection main valve and each ammonia injection branch valve.
Each group of inlet flue gas flow measuring devices comprise an inlet flue gas flow measuring device and a transmitter; and the flue gas flow signals of each corresponding inlet flue grid area are transmitted to the transmitter through the inlet flue gas flow pressure measuring device in sequence.
Each inlet flue gas sampling device is connected with an inlet flue gas analysis and control device through a corresponding sampling pipeline, and the inlet flue gas sampling switching valve device comprises an electric control valve arranged on each sampling pipeline.
Each outlet flue gas sampling device is connected with an outlet flue gas analysis and control device through a corresponding sampling pipeline, and each outlet flue gas sampling switching valve device comprises an electric control valve arranged on each sampling pipeline.
The ammonia spraying device also comprises an ammonia spraying main pipe connected with each ammonia spraying branch pipe; valves are respectively arranged on the ammonia spraying main pipe and each ammonia spraying branch pipe.
The inlet flue gas analysis and control device comprises a pretreatment device, an analyzer and a controller; the outlet flue gas analysis and control device comprises a pretreatment device, an analyzer and a controller.
The ammonia spraying main pipe is provided with an ammonia spraying main pipe flowmeter.
Each grid region of the inlet flue section corresponds to each grid region of the outlet flue section one by one; the size of the grid between the cross section of the inlet flue and the cross section of the outlet flue is (2 m-3 m) × (1 m-1.5 m).
Compared with the prior art, the utility model has the advantages of it is following:
1. the utility model discloses a carry out the net division that corresponds to entry flue cross-section and export flue cross-section, with each entry flue net sampling area and each export flue net sampling area one-to-one in groups correspond, carry out the analysis by detection to the entry flue sample flue gas and the export flue sample flue gas of each group respectively, and measure the flue gas flow of entry flue net region, calculate according to each group's detection and analysis data through DCS control system, control the ammonia injection volume of the entry flue sampling area of each group, thereby realize the subregion and spout ammonia control.
2. The utility model discloses a carry out the net with entry and export flue cross-section and divide the back and obtain a plurality of net sampling areas to every net sampling area sets up sampling pipeline all the way, selects sampling pipeline according to a certain order and draws the flue gas (select the same order that entry flue net sampling area and export flue net sampling area adopted to correspond), carries out preliminary treatment and cyclic analysis in turn to the flue gas that draws, calculates and obtains NOxDistribution data of concentration fields at inlet and outlet flue cross sections. Because all be provided with a sampling pipeline all the way in every net, overcome current denitrification facility and generally adopted one or three sampling point, perhaps a plurality of sampling point mixed sampling, carry out the deviation measured to SCR system entry and export concentration, make measured data more accurate, have comprehensive representativeness.
3. And simultaneously, the inlet flue gas flow is measured in a partition mode, so that the distribution data of the inlet section flue gas flow of the flue is measured. Inlet partition NOxThe concentration and the flue gas flow can be calculated to obtain the NO of the flue inlet partitionxMass while passing through the outlet zone NOxAnd concentration feedback is carried out, so that accurate control of ammonia/nitrogen molar ratio in different areas of an SCR denitration inlet is finally realized, and accurate basis is provided for differential ammonia injection regulation of an ammonia injection branch valve. And by pairing of the zones NOxAnd accumulating and calculating the mass in real time to obtain the required total ammonia injection amount, and providing an accurate basis for adjusting the total ammonia injection amount by using the total ammonia injection valve.
4. Adopt the utility model discloses spout ammonia optimal control system, reaching unit NOxThe concentration is reduced on the premise of reaching the emission standardThe over-spraying and under-spraying of ammonia can reduce the escape rate of ammonia, save energy, reduce consumption and improve the safety of the unit.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required to be used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the provided drawings without creative efforts.
FIG. 1 is a layout diagram of an ammonia injection optimization control system of the SCR flue gas denitration device of the utility model;
FIG. 2 is a schematic diagram of the ammonia injection amount control according to the present invention;
FIG. 3 is a schematic diagram of the ammonia injection zone differential control according to the present invention;
fig. 4 is a schematic flow chart of the ammonia injection optimization control method of the SCR flue gas denitration device.
Detailed Description
The technical solutions in the embodiments of the present invention will be described clearly and completely with reference to the accompanying drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments in the present invention, all other embodiments obtained by a person skilled in the art without creative work belong to the protection scope of the present invention.
The terms "first" and "second," and the like in the description and claims of the present invention and the above-described drawings are used for distinguishing between different objects and not for describing a particular order. Furthermore, the terms "comprising" and "having," as well as any variations thereof, are intended to cover non-exclusive inclusions. For example, a process, method, system, article, or apparatus that comprises a list of steps or elements is not set forth for a listed step or element but may include steps or elements not listed.
Example one
The embodiment of the utility model provides a do referring to fig. 1 the utility model provides a pair of SCR flue gas denitration device spouts ammonia optimal control system, its characterized in that carries out the meshing based on the net method with the flue cross-section, obtains flue cross-section sampling area. To inlet flue NOxConcentration zone measurement, flue gas flow zone measurement and outlet flue NOxConcentration subregion is measured and entry flue corresponds subregion and spouts ammonia, and this system includes: an inlet flue gas sampling device 1, an inlet flue gas flow measuring and pressure measuring device 2, a transmitter 3, an inlet switching valve 4, an inlet flue ammonia spraying branch valve 5, an inlet flue ammonia spraying main valve 7, an inlet flue ammonia spraying main pipe flowmeter 8, an inlet flue gas analyzing and controlling device 6, an outlet flue gas sampling device 10, an outlet switching valve 11, an outlet flue gas analyzing and controlling device 12 and a DCS control system 9, wherein,
the flue section sampling area is an inlet flue and an outlet flue grid sampling area obtained by correspondingly grid dividing the inlet flue section and the outlet flue section;
each inlet flue grid sampling area is correspondingly provided with an inlet flue gas flow pressure measuring device 2 and a transmitter 3, and the inlet flue gas flow pressure measuring device 2 is used for obtaining a flue gas flow differential pressure signal. The transmitter 3 is used for converting the obtained flue gas flow differential pressure signal into a standard electric signal, sending the standard electric signal into the inlet flue gas analysis and control device 6, and sending flue gas flow data to the DCS control system 9 through the inlet flue gas analysis and control device 6;
meanwhile, each inlet flue grid sampling area is correspondingly provided with an inlet flue gas sampling device 1 for performing dust removal treatment and sampling flue gas extraction on flue gas;
each outlet flue grid sampling area is correspondingly provided with an outlet flue gas sampling device 10 for performing dust removal treatment and sampling flue gas extraction on flue gas;
the inlet switching valve 4 receives a control instruction of the inlet flue gas analysis and control device 6 to select a sampling pipeline corresponding to an inlet (namely, a sampling pipeline connected with the inlet flue gas sampling device 1 connected with a corresponding inlet flue grid area is used for selecting an inlet flue grid sampling area corresponding to sampling);
the outlet switching valve 11 receives a sampling pipeline corresponding to a control instruction selection port of the outlet flue gas analysis and control device 12 (i.e. a sampling pipeline connected with the outlet flue gas sampling device 10 connected with a corresponding outlet flue grid region is used for selecting an outlet flue grid sampling region corresponding to sampling);
the inlet flue gas analyzing and controlling device 6 and the outlet flue gas analyzing and controlling device 12 are used for extracting, preprocessing and alternately and circularly measuring the sampled flue gas under the instruction of the DCS control system 9 and sending the measured data to the DCS control system 9;
each inlet grid sampling area is correspondingly provided with an inlet flue ammonia spraying branch valve 5 for controlling the ammonia spraying amount of each corresponding area;
meanwhile, an inlet flue ammonia spraying main valve 7 is arranged on the ammonia spraying main pipe and is used for controlling the total ammonia spraying amount of the SCR region;
an ammonia spraying main pipe flowmeter 8 is arranged on the ammonia spraying main pipe to measure the total ammonia amount sprayed to the SCR region in real time;
the DCS control system 9 calculates the flue gas analysis data to obtain NOxDistribution data of concentration fields on the inlet and outlet flue sections;
the DCS control system 9 calculates the flue gas flow differential pressure data to obtain flue gas flow subsection data on the section of the inlet flue;
the DCS control system 9 controls the system according to the SCR inlet NOxConcentration, inlet flue gas flow and outlet NOxAnd (4) establishing a control model for controlling the concentration, and performing feedforward, ammonia injection total amount closed-loop control and ammonia injection branch differentiated control.
The method comprises the steps of dividing grids according to the size of the cross section of a flue, arranging an inlet flue gas sampling device 1 in each grid of an inlet flue, switching through inlet switching valves 4, extracting through an inlet flue gas analysis and control device 6, preprocessing sampled flue gas, measuring in turn in a circulating manner, and further obtaining NO of the cross section of the whole inlet fluexDistribution data of concentration. IntoA flue gas flow pressure measuring device 2 and a transmitter 3 are arranged in each grid of the flue at the opening, so that distribution data of the flue gas flow of the section of the whole flue can be obtained. One outlet flue gas sampling device 10 is arranged in each grid of the outlet flue, and is switched by each outlet switching valve 11, extracted by the outlet flue gas analysis and control device 12, and the sampled flue gas is pretreated and alternately and circularly measured, so that the NO of the section of the whole outlet flue can be obtainedxDistribution data of concentration. A flue gas flow pressure measuring device 2 and a transmitter 3 are arranged in each grid of the inlet flue, so that distribution data of the flue gas flow of the section of the whole inlet flue can be obtained. Each inlet flue ammonia injection branch valve 5 corresponds to one inlet flue grid sampling area.
The above corresponding meshing is performed for the inlet flue cross section and the outlet flue cross section, for example: if the size of the cross section of the inlet flue is 10 meters long and 2.5 meters wide, 8 grid sampling areas are divided according to the length of 2.5 meters and the width of 1.25 meters. The cross section of the outlet flue is 10 meters long and 3 meters wide, and the outlet flue is correspondingly divided into 8 grid sampling areas according to the length of 2.5 meters and the width of 1.5 meters. The 8 grid sampling areas of the inlet and the outlet are in one-to-one correspondence according to the areas (for example, according to the flow direction of flue gas, the inlet flue grid sampling area and the outlet flue grid sampling area are in one-to-one correspondence in a mirror image mode).
The inlet flue gas sampling device 1 is used for performing dust removal treatment and sampling flue gas extraction on flue gas;
the outlet flue gas sampling device 10 is used for performing dust removal treatment and sampling flue gas extraction on flue gas;
the inlet switching valve 4 can switch the sampling points to be analyzed according to a certain sequence and requirements according to the control instruction of the inlet flue gas analysis and control device 6, namely, the corresponding inlet flue gas sampling device 1 is selected according to the instruction sequence;
the outlet switching valve 11 can switch sampling points to be analyzed according to a certain sequence and requirements according to a control instruction of the outlet flue gas analyzing and controlling device 12, that is, the corresponding outlet flue gas sampling device 10 is selected according to the instruction sequence;
the transmitter 3 is used for converting the obtained flue gas flow differential pressure signal into a standard electric signal, sending the standard electric signal to the inlet flue gas analysis and control device 6, and sending flue gas flow data to the DCS control system 9 through the inlet flue gas analysis and control device 6;
the inlet flue gas analysis and control device 6 is used for extracting, preprocessing and alternately and circularly measuring the sampled flue gas under the instruction of the DCS control system 9 and sending the measured data to the DCS control system 9;
the outlet flue gas analyzing and controlling device 12 is used for extracting, preprocessing and alternately and circularly measuring the sampled flue gas under the instruction of the DCS control system 9 and sending the measured data to the DCS control system 9;
each inlet flue ammonia injection branch valve 5 corresponds to one inlet grid sampling area and is used for controlling the ammonia injection amount of each corresponding area under the instruction of the DCS control system 9;
the inlet flue ammonia injection main valve is used for controlling the total ammonia injection amount of the SCR region and is connected with the inlet flue ammonia injection branch valves 5 in parallel;
the ammonia injection main pipe is provided with an ammonia injection main pipe flowmeter 8 for measuring the total ammonia injection amount in real time in the SCR region;
referring to fig. 2, the DCS control system 9 controls the flue gas NO for each inlet flue grid areaxThe concentration and the smoke flow are calculated, and then the smoke NO of the inlet flue grid area is obtainedxThe total amount M and the measured and calculated concentration N are specifically calculated by the formula
Wherein KiFor measuring the correction factor, KiThe method through the instrument cold state experiment gains, 8 measurement subareas in the utility model, lay 5 cold state measurement stations in addition to every subarea when cold state is experimental, and the flow measurement value of 5 cold state measurement stations is revised with the single measurement station flow measurement value of online instrument when through cold state experiment. SiFor the flue gas flow of the ith inlet flue grid sampling area, QiFor sampling section of ith inlet flue gridNO of flue gasxAnd (4) concentration. Meanwhile, the comprehensive calculation result of parameters such as the total air quantity of the unit operation is combined to be used as the feedforward quantity in the ammonia injection total quantity control system, and NO is dischargedxAnd after the concentration set value is compared with the deviation of the measured and calculated concentration N for operation control, the concentration set value is operated with the introduced feed-forward quantity to be used as a set value of an ammonia injection total quantity controller, and the ammonia injection total quantity of the SCR region is accurately controlled through an inlet flue ammonia injection main valve 7. A feed forward quantity of
Wherein y is the total air quantity of the unit in operation, kdAnd b is a correction base number. Due to NOxThe measurement of the concentration has larger hysteresis, and the introduction of the feedforward quantity can be carried out on the unit NOxWhen the concentration is increased, a signal is sent to the denitration ammonia injection controller in advance to prepare for increasing the ammonia injection amount in advance so as to control and prevent NO from being discharged in timexThe concentration exceeds the standard.
Referring to fig. 3, the DCS control system 9 samples the flue gas NO of each outlet flue grid sampling areaxConcentration and outlet NOxAnd comparing, calculating and controlling the deviation of the concentration set value, respectively combining the flue gas flow of the inlet flue grid sampling area corresponding to each outlet flue grid sampling area and the measurement correction coefficient of the inlet flue grid sampling area, respectively giving an opening instruction of the ammonia spraying branch valve 5 of each inlet flue after optimization calculation of a differentiation calculator, and performing differentiation ammonia spraying on each sampling area. The scheme makes full use of the one-to-one correspondence relationship between the inlet flue grid sampling area and the outlet flue grid sampling area, and measures, compares and sprays ammonia control in time, thereby further improving the control precision. In the optimization operation formula of the differential operator
Wherein QsIs export NOXThe concentration set point.
Through the embodiment of the utility model provides a public technical scheme obtains a plurality of net sampling areas through carrying out the meshing with entry and export flue cross-section after to every net sampling area sets up sampling pipeline all the way, according to certainSequentially selecting sampling pipelines to extract smoke, carrying out pretreatment and alternate circulation analysis on the extracted smoke, and calculating to obtain NOxDistribution data of concentration fields at inlet and outlet flue cross sections. Because all be provided with a sampling pipeline all the way in every net, overcome current denitrification facility and generally adopted one or three sampling point to and a plurality of sampling point mix the sample, carry out the deviation measured to SCR system entry and export concentration, make measured data more accurate, have comprehensive representativeness. And simultaneously, the inlet flue gas flow is measured in a partition mode, so that the distribution data of the flue gas flow of the inlet section of the flue are measured. Inlet partition NOxThe concentration and the flue gas flow can be calculated to obtain the NO of the flue inlet partitionxQuality, simultaneously fully utilizing the one-to-one correspondence relationship of the inlet and outlet flue section grids, and partitioning NO through an outletxAnd (3) concentration feedback, wherein a differential arithmetic unit in the DCS control system 9 implements optimization operation, provides accurate instructions for the differential ammonia injection regulation of the ammonia injection branch valve 5, and carries out measurement, comparison and ammonia injection control in time, so that the accurate control of the ammonia/nitrogen molar ratio of different areas of the SCR denitration inlet is realized. For simultaneous division of NOxAccumulating and calculating the mass in real time to obtain the required total ammonia spraying amount, and taking the comprehensive calculation result of parameters such as operation load, total air volume and the like as the feedforward amount in the total ammonia spraying amount control system in a DCS (distributed control system) 9xAnd after the concentration set value is compared with the deviation of the measured and calculated concentration N for operation control, the concentration set value is operated with the introduced feed-forward quantity to be used as a set value of an ammonia injection total quantity controller, and the ammonia injection total quantity of the SCR region is accurately controlled through an inlet flue ammonia injection main valve 7. Through the control strategy, the NO of the unit is achievedxOn the premise of standard emission of the concentration, over-spraying and under-spraying of ammonia are reduced, the ammonia escape rate is reduced, energy is saved, consumption is reduced, and the safety of a unit is improved.
Example two
With the embodiment of the utility model provides a disclosed SCR flue gas denitration device spouts ammonia optimal control system corresponding, the utility model discloses an embodiment two still provides a SCR flue gas denitration device spouts ammonia optimal control system method, refers to figure 4, and this method includes:
s11, meshing the inlet and outlet flue sections based on a meshing method to obtain a plurality of mesh sampling areas;
s12, preprocessing the sampled flue gas of the inlet flue and measuring in turn to obtain NO of the inlet fluexConcentration zone measurements;
s13, carrying out partition measurement on the inlet flue gas flow simultaneously;
s14, preprocessing the sampled flue gas of the outlet flue and measuring in turn to obtain NO of the outlet fluexConcentration zone measurements;
s15, the DCS control system carries out analog calculation on the measured data of the partition and gives out the inlet NOxConcentration, inlet flue gas flow and outlet NOxA concentration measurement calculation;
s16, DCS adopts advanced control algorithm, not only controls the total ammonia spraying amount, but also controls the ammonia spraying branch in a partition mode;
in the second embodiment of the present invention, the inlet and outlet flue sections are gridded based on a gridding method to obtain a plurality of grid sampling areas; every net sampling area sets up a sampling pipeline all the way, has overcome current denitrification facility and has generally adopted one or three sampling point to and a plurality of sampling point mix the sample, carries out the deviation measured to SCR system entry and export concentration, makes measured data more accurate, has comprehensive representativeness. Extracting, pretreating and measuring the sampled flue gas of the inlet flue in turn to obtain NO of the inlet fluexConcentration zone measurements; and simultaneously, the flue gas flow of the inlet flue is measured in a subarea mode, so that the respective data of the flue gas flow of the inlet section of the flue is measured. Inlet partition NOxThe concentration and the flue gas flow can be calculated to obtain the NO of the flue inlet partitionxQuality, simultaneously fully utilizing the one-to-one correspondence relationship of the inlet and outlet flue section grids, and partitioning NO through an outletxAnd (3) concentration feedback, wherein optimization operation is implemented by a differential operator in the DCS control system, so that an accurate instruction is provided for the differential ammonia injection regulation of the ammonia injection branch valve, measurement, comparison and ammonia injection control are carried out in time, and the accurate control of the ammonia/nitrogen molar ratio of different areas of the SCR denitration inlet is realized. For simultaneous division of NOxThe quality is accumulated and calculated in real time to obtain the requirementThe obtained total ammonia spraying amount is combined with the comprehensive calculation results of parameters such as operation load, total air volume and the like in a DCS control system to be used as a feedforward amount in the total ammonia spraying amount control system, and the calculated total ammonia spraying amount is used as a feedforward amount in NOxAnd after the concentration set value is compared with the deviation of the measured and calculated concentration N for operation control, the concentration set value is operated with the introduced feed-forward quantity to be used as a set value of an ammonia spraying total quantity controller, and the ammonia spraying total quantity of the SCR region is accurately controlled through an inlet flue ammonia spraying main valve. Through the control strategy, the NO of the unit is achievedxOn the premise of standard emission of the concentration, over-spraying and under-spraying of ammonia are reduced, the ammonia escape rate is reduced, energy is saved, consumption is reduced, and the safety of a unit is improved.
The embodiments in the present description are described in a progressive manner, each embodiment focuses on differences from other embodiments, and the same and similar parts among the embodiments are referred to each other. The device disclosed by the embodiment corresponds to the method disclosed by the embodiment, so that the description is simple, and the relevant points can be referred to the method part for description.
The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.
Claims (10)
1. The utility model provides a SCR flue gas denitrification facility spouts ammonia optimal control system which characterized in that: the ammonia spraying optimization control system comprises a plurality of inlet flue gas sampling devices, a plurality of groups of inlet flue gas flow measuring devices, an inlet flue gas analyzing and controlling device, an inlet flue gas sampling switching valve device, a plurality of outlet flue gas sampling devices, an outlet flue gas analyzing and controlling device, an ammonia spraying device and a DCS control system; wherein the content of the first and second substances,
the inlet flue gas sampling devices respectively correspond to each grid area of the section of the inlet flue;
the multiple groups of inlet flue gas flow measuring devices respectively correspond to each grid area of the section of the inlet flue and are connected with the inlet flue gas analysis and control device;
the inlet flue gas analysis and control device is connected with the plurality of inlet flue gas sampling devices through the inlet flue gas sampling switching valve device and is connected with the DCS control system;
the outlet flue gas sampling devices respectively correspond to each grid area of the section of the outlet flue;
the outlet flue gas analysis and control device is connected with the outlet flue gas sampling devices through the outlet flue gas sampling switching valve device and is connected with the DCS control system;
the ammonia spraying device comprises an ammonia spraying main valve, a plurality of ammonia spraying branch pipes and an ammonia spraying branch valve, and the ammonia spraying main valve, the plurality of ammonia spraying branch pipes and the ammonia spraying branch valves respectively correspond to each grid area of the cross section of the inlet flue;
the DCS control system is connected with the ammonia injection main valve and each ammonia injection branch valve in a control mode.
2. The ammonia injection optimization control system of claim 1, wherein: each group of inlet flue gas flow measuring devices comprises an inlet flue gas flow measuring device and a transmitter; the flue gas of each corresponding inlet flue grid area sequentially passes through an inlet flue sampling switching valve device to an inlet flue gas analysis and control device; and the flue gas flow signals of the corresponding inlet flue grid areas are transmitted to the transmitter through the inlet flue gas flow pressure measuring device.
3. The ammonia injection optimization control system of claim 2, wherein: each inlet flue gas sampling device is connected with an inlet flue gas analysis and control device through a corresponding sampling pipeline, and the inlet flue gas sampling switching valve device comprises an electric control valve arranged on each sampling pipeline.
4. The ammonia injection optimization control system of claim 3, wherein: and the inlet flue gas analysis and control device is connected with the electric control valves on the sampling pipelines in a control way.
5. The ammonia injection optimization control system of claim 3, wherein: each outlet flue gas sampling device is connected with an outlet flue gas analysis and control device through a corresponding sampling pipeline, and each outlet flue gas sampling switching valve device comprises an electric control valve arranged on each sampling pipeline.
6. The ammonia injection optimization control system of claim 5, wherein: and the outlet flue gas analysis and control device is connected with the electric control valve on the sampling pipeline of each outlet flue gas sampling device in a control way.
7. The ammonia injection optimization control system of claim 5, wherein: the ammonia spraying device also comprises an ammonia spraying main pipe connected with each ammonia spraying branch pipe; and valves are respectively arranged on the ammonia spraying main pipe and each ammonia spraying branch pipe.
8. The ammonia injection optimization control system of claim 7, wherein: the inlet flue gas analysis and control device comprises a pretreatment device, an analyzer and a controller; the outlet flue gas analysis and control device comprises a pretreatment device, an analyzer and a controller.
9. The ammonia injection optimization control system of claim 8, wherein: the size of the grid area of the inlet flue section and the grid area of the outlet flue section is (1-1.5 m) x (2-2.5 m).
10. The ammonia injection optimization control system of claim 9, wherein: the inlet flue section and the outlet flue section are divided into 8 corresponding grid areas.
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114199450A (en) * | 2021-12-15 | 2022-03-18 | 国家能源集团谏壁发电厂 | Pressure measuring probe, flue gas denitration full-section pressure distribution measuring device and measuring method |
| CN114259855A (en) * | 2021-12-27 | 2022-04-01 | 国能神皖安庆发电有限责任公司 | Denitration system and control method thereof |
| CN115155362A (en) * | 2022-07-29 | 2022-10-11 | 西安热工研究院有限公司 | Dynamic large-range mixing system suitable for rectangular section channel |
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2020
- 2020-04-09 CN CN202020509925.XU patent/CN212167066U/en active Active
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114199450A (en) * | 2021-12-15 | 2022-03-18 | 国家能源集团谏壁发电厂 | Pressure measuring probe, flue gas denitration full-section pressure distribution measuring device and measuring method |
| CN114259855A (en) * | 2021-12-27 | 2022-04-01 | 国能神皖安庆发电有限责任公司 | Denitration system and control method thereof |
| CN115155362A (en) * | 2022-07-29 | 2022-10-11 | 西安热工研究院有限公司 | Dynamic large-range mixing system suitable for rectangular section channel |
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