CN111523246B - Composite flue gas flow field measurement method and measurement system - Google Patents
Composite flue gas flow field measurement method and measurement system Download PDFInfo
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- UGFAIRIUMAVXCW-UHFFFAOYSA-N Carbon monoxide Chemical compound [O+]#[C-] UGFAIRIUMAVXCW-UHFFFAOYSA-N 0.000 title claims abstract description 160
- 239000003546 flue gas Substances 0.000 title claims abstract description 160
- 238000005259 measurement Methods 0.000 title claims abstract description 132
- 239000002131 composite material Substances 0.000 title claims abstract description 23
- 238000000691 measurement method Methods 0.000 title claims description 6
- 239000003344 environmental pollutant Substances 0.000 claims abstract description 90
- 231100000719 pollutant Toxicity 0.000 claims abstract description 90
- 238000012937 correction Methods 0.000 claims abstract description 40
- 238000004088 simulation Methods 0.000 claims abstract description 40
- 238000000034 method Methods 0.000 claims abstract description 31
- 238000004364 calculation method Methods 0.000 claims abstract description 14
- 238000005192 partition Methods 0.000 claims description 73
- 238000005070 sampling Methods 0.000 claims description 43
- 238000004868 gas analysis Methods 0.000 claims description 28
- 238000012545 processing Methods 0.000 claims description 24
- 239000000779 smoke Substances 0.000 claims description 22
- 238000007781 pre-processing Methods 0.000 claims description 5
- 230000008569 process Effects 0.000 claims description 5
- 230000002159 abnormal effect Effects 0.000 claims description 4
- 238000005265 energy consumption Methods 0.000 abstract description 4
- QGZKDVFQNNGYKY-UHFFFAOYSA-N Ammonia Chemical compound N QGZKDVFQNNGYKY-UHFFFAOYSA-N 0.000 description 14
- 239000000523 sample Substances 0.000 description 13
- 229910021529 ammonia Inorganic materials 0.000 description 7
- 238000006477 desulfuration reaction Methods 0.000 description 7
- 230000023556 desulfurization Effects 0.000 description 7
- 230000007547 defect Effects 0.000 description 6
- 239000000428 dust Substances 0.000 description 6
- 238000007664 blowing Methods 0.000 description 5
- 239000007789 gas Substances 0.000 description 5
- MWUXSHHQAYIFBG-UHFFFAOYSA-N Nitric oxide Chemical compound O=[N] MWUXSHHQAYIFBG-UHFFFAOYSA-N 0.000 description 3
- 238000004458 analytical method Methods 0.000 description 3
- 239000003795 chemical substances by application Substances 0.000 description 3
- 125000004122 cyclic group Chemical group 0.000 description 3
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 2
- RAHZWNYVWXNFOC-UHFFFAOYSA-N Sulphur dioxide Chemical compound O=S=O RAHZWNYVWXNFOC-UHFFFAOYSA-N 0.000 description 2
- 230000003009 desulfurizing effect Effects 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 238000002347 injection Methods 0.000 description 2
- 239000007924 injection Substances 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 230000005856 abnormality Effects 0.000 description 1
- 230000000903 blocking effect Effects 0.000 description 1
- 230000008859 change Effects 0.000 description 1
- 238000010276 construction Methods 0.000 description 1
- 239000000356 contaminant Substances 0.000 description 1
- 230000002708 enhancing effect Effects 0.000 description 1
- 230000007613 environmental effect Effects 0.000 description 1
- 238000009434 installation Methods 0.000 description 1
- 229910052757 nitrogen Inorganic materials 0.000 description 1
- 230000002265 prevention Effects 0.000 description 1
- 230000000750 progressive effect Effects 0.000 description 1
- 230000001105 regulatory effect Effects 0.000 description 1
- 239000000243 solution Substances 0.000 description 1
- 238000005507 spraying Methods 0.000 description 1
- 230000009466 transformation Effects 0.000 description 1
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- G06F30/00—Computer-aided design [CAD]
- G06F30/20—Design optimisation, verification or simulation
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N1/00—Sampling; Preparing specimens for investigation
- G01N1/02—Devices for withdrawing samples
- G01N1/22—Devices for withdrawing samples in the gaseous state
- G01N1/2247—Sampling from a flowing stream of gas
- G01N1/2258—Sampling from a flowing stream of gas in a stack or chimney
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N33/00—Investigating or analysing materials by specific methods not covered by groups G01N1/00 - G01N31/00
- G01N33/0004—Gaseous mixtures, e.g. polluted air
- G01N33/0009—General constructional details of gas analysers, e.g. portable test equipment
- G01N33/0027—General constructional details of gas analysers, e.g. portable test equipment concerning the detector
- G01N33/0031—General constructional details of gas analysers, e.g. portable test equipment concerning the detector comprising two or more sensors, e.g. a sensor array
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N33/00—Investigating or analysing materials by specific methods not covered by groups G01N1/00 - G01N31/00
- G01N33/0004—Gaseous mixtures, e.g. polluted air
- G01N33/0009—General constructional details of gas analysers, e.g. portable test equipment
- G01N33/0027—General constructional details of gas analysers, e.g. portable test equipment concerning the detector
- G01N33/0036—General constructional details of gas analysers, e.g. portable test equipment concerning the detector specially adapted to detect a particular component
- G01N33/0037—NOx
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N33/00—Investigating or analysing materials by specific methods not covered by groups G01N1/00 - G01N31/00
- G01N33/0004—Gaseous mixtures, e.g. polluted air
- G01N33/0009—General constructional details of gas analysers, e.g. portable test equipment
- G01N33/0027—General constructional details of gas analysers, e.g. portable test equipment concerning the detector
- G01N33/0036—General constructional details of gas analysers, e.g. portable test equipment concerning the detector specially adapted to detect a particular component
- G01N33/0042—SO2 or SO3
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01P—MEASURING LINEAR OR ANGULAR SPEED, ACCELERATION, DECELERATION, OR SHOCK; INDICATING PRESENCE, ABSENCE, OR DIRECTION, OF MOVEMENT
- G01P5/00—Measuring speed of fluids, e.g. of air stream; Measuring speed of bodies relative to fluids, e.g. of ship, of aircraft
- G01P5/14—Measuring speed of fluids, e.g. of air stream; Measuring speed of bodies relative to fluids, e.g. of ship, of aircraft by measuring differences of pressure in the fluid
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- G01—MEASURING; TESTING
- G01P—MEASURING LINEAR OR ANGULAR SPEED, ACCELERATION, DECELERATION, OR SHOCK; INDICATING PRESENCE, ABSENCE, OR DIRECTION, OF MOVEMENT
- G01P5/00—Measuring speed of fluids, e.g. of air stream; Measuring speed of bodies relative to fluids, e.g. of ship, of aircraft
- G01P5/14—Measuring speed of fluids, e.g. of air stream; Measuring speed of bodies relative to fluids, e.g. of ship, of aircraft by measuring differences of pressure in the fluid
- G01P5/16—Measuring speed of fluids, e.g. of air stream; Measuring speed of bodies relative to fluids, e.g. of ship, of aircraft by measuring differences of pressure in the fluid using Pitot tubes, e.g. Machmeter
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- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06F—ELECTRIC DIGITAL DATA PROCESSING
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Abstract
The invention discloses a method for measuring a composite flue gas flow field, which comprises the steps of establishing a flue gas flow field large database under different working conditions through numerical simulation calculation, acquiring measurement data of a flue gas speed field, a flow vector field and a pollutant concentration field of a real-time flue section, and carrying out superposition correction on the database and the measurement data to obtain final flue gas flow field data. According to the invention, the theoretical simulation value and the measured data are overlapped and corrected, so that the corrected measured data are more accurate, a basis is provided for accurate control of pollutants, standard emission is ensured, the safety of a unit is improved, and the energy consumption of the pollutants is reduced.
Description
Technical Field
The invention belongs to the technical field of smoke pollutant control, and particularly relates to a composite smoke flow field measurement system and method based on combination of unit big data soft measurement and an online continuous measurement device.
Background
The pollution prevention and treatment combat is well carried out, the strong outstanding environmental problems reflected by people with good quality are solved, the urgent need of improving the environment civilian life is satisfied, and the urgent need of enhancing the ecological civilization construction is also satisfied. The comprehensive treatment of the atmospheric environment is continuously advanced while the strength and vigor of attack are maintained. The country has issued a series of policies and measures that require thermal power plants to implement ultra-low emission modifications. In the flue gas pollutant sulfur dioxide and nitrogen oxide removal transformation, some positive measures are taken. Basically, the flue gas flow field is optimally designed and modified, and the flue gas flow velocity and the pollutant concentration distribution uniformity of the section of the flue are improved. Most devices have limited space and cannot meet the ideal requirements. Such as SCR denitration device inlet NO x The number of the concentration measuring probes is increased from one to three, or a multipoint mixed sampling method is adopted; desulfurization unit inlet SO 2 The concentration measurement usually adopts a measuring probe; the flue gas flow rate measurement is also a method for taking average pressure by multipoint mixing; these methods still leave contaminant concentration and flue gas flow rate measurement data not representative, and do not measure the actual concentration, actual flow rate, and actual flow direction across the flue cross section. Inaccurate measurement cannot provide basis for accurate control of pollutants, such as denitration ammonia injection control, and cannot be controlled according to different NO in each area of the section of the flue x Concentration, ammonia spraying amount is regulated to result in uneven ammonia/nitrogen molar ratio in the cross section of the flue, excessive ammonia results in increased ammonia escape from the outlet of the SCR reactor, and insufficient ammonia results in NO x The discharge concentration exceeds the standard. The uneven speed field also has a certain influence on the ammonia injection control precision. For example, the desulfurization agent addition amount of the desulfurization system is controlled, SO that the SO at the inlet of the desulfurization device is not accurately measured 2 Concentration and flow rate, the SO to be removed cannot be calculated 2 The actual quantity cannot accurately control the addition amount of the desulfurizing agent, SO that SO is caused 2 The fluctuation range of the emission concentration is increased, the emission concentration exceeds the standard, or the emission concentration is too low, so that the consumption of the desulfurizing agent is increased.
Disclosure of Invention
The invention aims to solve the defects in the prior art and provides a composite flue gas flow field measurement system capable of effectively improving measurement accuracy.
In order to achieve the above purpose, the invention provides a composite flue gas flow field measurement method, which is calculated by numerical simulation theory, establishes a large unit flow field database under different working conditions, corrects actual measurement values, and corrects flow fields and concentration fields under the working conditions in the large unit flow field database by combining actual measurement correction data, thereby acquiring flue gas data under real-time working conditions.
Specifically, the composite flue gas flow field measurement method comprises the steps of carrying out grid division on the section of a flue to obtain a plurality of grid partitions, carrying out numerical simulation theoretical calculation, establishing a large unit flow field database under different working conditions, carrying out real-time measurement on the flow velocity and pollutant concentration of flue gas in the section of the flue, correcting real-time measurement data through theoretical simulation data of the large unit flow field database, and correcting the flow field and concentration field under the working conditions in the large unit flow field database by combining actual measurement correction data, thereby obtaining flue gas data under the real-time working conditions.
The theoretical simulation data of the large database of the unit flow field comprises a flue section speed field, a flow direction vector field and a pollutant concentration field.
The obtained flue gas data under the real-time working condition comprises a flue section speed field, a vector field, a pollutant concentration field and section flue gas flow and pollutant concentration soft measurement data.
More specifically, the method for measuring the composite flue gas flow field comprises the following steps:
s11, grid dividing is carried out on the section of the flue according to the size of the section of the flue based on a grid method, so that a plurality of grid partitions are obtained;
s12, carrying out numerical simulation on values of the section partition flue gas velocity field, the vector field and the pollutant concentration field under different loads;
s13, carrying out theoretical simulation to obtain theoretical simulation data of a zoned speed field, a vector field and a pollutant concentration field under different working conditions, and establishing a flow field big database;
s14, sampling, preprocessing and circularly measuring the flue gas in the flue subareas to obtain a partitioned actual measurement value of the pollutant concentration of the cross section of the flue;
s15, simultaneously carrying out zone measurement on the flue gas flow velocity of the flue to obtain a flue gas zone flow velocity actual measurement value;
s16, combining numerical simulation theory calculation data, correcting the partition actual measurement value, and giving measurement correction data of the partition flow velocity field, the pollutant concentration field, the section flue gas flow and the pollutant concentration;
s17, correcting the large database of the unit flow field by combining the measurement correction data to obtain real-time soft measurement data of the speed field, the pollutant concentration field, the section flue gas flow and the pollutant concentration of each partition.
In step S16, the correction of the partition measured value at least includes correction of the flow vector field to the measured value of the flow velocity of the flue gas, correction of the flow field large database of the flow vector field, the flow velocity field and the concentration field to the measured flow velocity field and the measured pollutant concentration field, and the correction process includes both rejection and correction of measured abnormal values which do not conform to the theoretical calculation and correction of influence of deviation of the flow direction and the ideal flow direction on the measuring instrument.
The specific method for correcting the flue gas flow velocity measurement value by the flow direction vector field comprises the following steps: and combining numerical simulation theory calculation data to obtain an actual measurement flow velocity deviation angle, so as to correct the actual measurement value of the flue gas flow velocity, and further correct the flue gas flow velocity field and the pollutant concentration field.
The invention also provides a composite flue gas flow field measurement system which is used for the flue section of the grid partition, and the unit-based big data soft measurement device is combined with the online continuous measurement device, wherein the online continuous measurement device comprises a plurality of paths of flue gas sampling devices which are in one-to-one correspondence with the grid partition, a plurality of paths of flue gas flow rate measurement devices which are in one-to-one correspondence with the grid partition, and a flue gas analysis and control device; the unit big data soft measuring device adopts a server operation processing system connected with a unit SIS system; the flue gas analysis and control device is respectively connected with each flue gas sampling device and each flue gas flow rate measuring device; the server operation processing system is respectively connected with the flue gas analysis and control device.
The flue gas flow velocity measuring device comprises a flue gas flow velocity pressure measuring device, a pressure measuring valve and a differential pressure transmitter.
Wherein,
the grid partition is a region for dividing the cross section of the flue into grids according to the size of the cross section of the flue based on a grid method;
each path of flue gas sampling device corresponds to one grid partition and is used for carrying out dust removal treatment and sampling on the flue partition sample gas;
each path of sampling valve corresponds to one path of flue gas sampling device, under the control of the flue gas analysis and control device, sampling flue gas of a required partition is switched and selected, and under the control of the flue gas analysis and control device, the flue gas sampling device is back-blown (by arranging a conventional back-blowing device) to prevent dust blockage;
each path of flue gas flow velocity pressure-taking device corresponds to one grid partition and is used for obtaining differential pressure signals of the partitioned flue gas flow velocity;
the differential pressure transmitter is used for converting the acquired smoke flow velocity actual measurement differential pressure signal corresponding to the flow velocity into an electric signal and transmitting the electric signal to the flue gas analysis and control device;
each differential pressure transmitter corresponds to one path of pressure taking valve;
each path of pressure-taking valve corresponds to one path of flue gas flow speed pressure-taking device, under the control of the flue gas analysis and control device, flow speed differential pressure is obtained, flow speed actual measurement data are sent to the flue gas analysis and control device through the differential pressure transmitter, and under the control of the flue gas analysis and control device, the flue gas flow speed pressure-taking device is back-blown (by arranging a conventional back-blowing device) to prevent dust from blocking;
the flue gas analysis and control device is used for preprocessing and circularly and alternately analyzing the extracted sampling flue gas to obtain actual measurement data of pollutant components of each partition, and transmitting the actual measurement data of pollutant components of each partition and flue gas flow velocity to the server operation processing system;
the server operation processing system theoretically simulates the data of the flue gas velocity field, the vector field and the pollutant concentration field of each section partition under different working conditions based on unit basic parameters and operation big data from a unit SIS system and builds a big database;
the server operation processing system corrects the measured values of all the subareas under the real-time working condition by utilizing a large flow field database of the unit to obtain the corrected measured data of the speed field, the pollutant concentration field, the section flue gas flow and the pollutant concentration of all the subareas;
and the server operation processing system corrects the large database of the unit flow field by combining the corrected measured data under the real-time working condition to obtain the soft measurement data of the flue section speed field, the flow vector field, the pollutant concentration field, the section flue gas flow and the pollutant concentration under the real-time working condition.
The big data soft measuring device of the unit is combined with an on-line continuous measuring device to form a smoke flow field composite measuring system.
The server operation processing system corrects the measured values of all the subareas under the real-time working condition by utilizing a large flow field database of the unit, the correction content at least comprises correction of the flow vector field to the measured value of the flue gas flow velocity, correction of the flow vector field, the flow velocity field and the large concentration field database to the measured flow velocity field and the measured pollutant concentration field, and the correction process comprises removal and correction of abnormal values which do not accord with theoretical calculation and correction of influence of deviation of the flow direction and the ideal flow direction on a measuring instrument.
Compared with the prior art, the invention has the following advantages:
1. according to the invention, superposition correction is carried out through theoretical simulation data and actual measurement data, so that the measurement accuracy is effectively improved.
2. According to the invention, a plurality of grid partitions are obtained after grid division is carried out on the section of the flue, each grid partition is provided with a sampling device, partition pipelines are selected according to the requirement through sampling valves, and the extracted sample gas is preprocessed and circularly and alternately analyzed to obtain the actual measurement value of the pollutant concentration partition and the distribution data of the pollutant concentration field on the section of the flue. Due to each gridThe inside is provided with sampling devices, and three measuring probes or multipoint mixed sampling are generally adopted for NOx concentration measurement of the existing denitration device, and the desulfurization device SO is overcome 2 The concentration measurement usually adopts a measuring probe, and the flue gas flow rate measurement adopts the defect of a multipoint mixing average pressure taking method, so that the pollutant concentration and flue gas flow rate measurement data are more representative and are closer to the actual value of the section of the whole flue.
3. Meanwhile, on the basis, numerical simulation is carried out on flow fields of the section partition smoke speed field, the vector field and the pollutant concentration field under different working conditions by utilizing unit basic parameters and operation big data from a unit SIS system, a unit flow field big database under different working conditions is established, and soft measurement data of the section partition speed field, the vector field, the pollutant concentration field, the section smoke flow and the pollutant concentration are obtained by repeatedly superposing and correcting theoretical simulation values and real-time measurement values. The soft measurement data of the flow field not only eliminates abnormal values of measured data through theoretical simulation, but also corrects the flow velocity measuring instrument according to a proper amount of flow field, the corrected flow velocity measurement value is more accurate, the flow field of the section of the flue is simulated by using big data combined with the running data of the unit, the measured data is corrected by using a flow field database after numerical simulation correction, and then the corrected measured data is used for further correcting the soft measurement data of the flow field of the unit under the real-time working condition. The complex measurement of the flue gas flow field is realized by repeatedly eliminating the abnormality and mutually correcting the theoretical actual measurement, the measurement precision is further improved, the basis is provided for the accurate control of pollutants, the standard emission is ensured, the safety of a unit is improved, and the energy consumption of the matters is reduced.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings that are required to be used in the embodiments or the description of the prior art will be briefly described below, and it is obvious that the drawings in the following description are only embodiments of the present invention, and that other drawings can be obtained according to the provided drawings without inventive effort for a person skilled in the art.
FIG. 1 is a layout diagram of a composite flue gas flow field measurement system based on combination of unit big data soft measurement and an on-line continuous measurement device according to a first embodiment of the present invention;
FIG. 2 is a schematic diagram of correction of flow velocity vector versus flow velocity value according to a first embodiment of the present invention;
fig. 3 is a schematic flow chart of a method for measuring a flow field of a composite flue gas based on combination of unit big data soft measurement and an on-line continuous measurement device according to a second embodiment of the invention.
Detailed Description
The following description of the embodiments of the present invention will be made clearly and completely with reference to the accompanying drawings, in which it is apparent that the embodiments described are only some embodiments of the present invention, but not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
The terms first and second and the like in the description and in the claims and in the above-described figures are used for distinguishing between different objects and not necessarily for describing a sequential or chronological order. Furthermore, the terms "comprise" and "have," as well as any variations thereof, are intended to cover a non-exclusive inclusion. For example, a process, method, system, article, or apparatus that comprises a list of steps or elements is not necessarily limited to the listed steps or elements but may include steps or elements not expressly listed.
Example 1
Referring to fig. 1, a system for measuring a composite flue gas flow field based on combination of unit big data soft measurement and an on-line continuous measurement device is provided in an embodiment of the invention, which is characterized in that grid division is performed on a flue section according to the size of the flue section based on a grid method to obtain a plurality of partitions, the flue section flue gas flow velocity partition real-time measurement, the pollutant concentration partition real-time measurement, the numerical simulation of each partition speed field, vector field and pollutant concentration field by using unit big data, a unit flow field big database under different working conditions is established, and the unit flow field big database under different working conditions is obtained by repeatedly overlapping and correcting theoretical simulation values and actual measurement values, so as to obtain the speed field, the vector field and the pollutant concentration field of each partition under the real-time working conditions, and the soft measurement data of the section flue gas flow and the pollutant concentration, and the composite flue gas flow field combined by the unit big data soft measurement and the on-line continuous measurement device is realized, and the system comprises: the system comprises a flue gas sampling device 1, a sampling valve 2, a flue gas flow velocity pressure-taking device 3, a pressure-taking valve 4, a differential pressure transmitter 5, a flue gas analysis and control device 6 and a server operation processing system 7. Wherein,
the grid partition is a region for dividing the cross section of the flue into grids according to the size of the cross section of the flue based on a grid method;
each path of flue gas sampling device 1 corresponds to a grid partition and is used for carrying out dust removal treatment and sampling on flue partition sample gas;
each path of sampling valve 2 corresponds to one path of flue gas sampling device 1, sampling flue gas of a required partition is switched and selected under the control of the flue gas analysis and control device 6, and back blowing (a conventional back blowing device is adopted and is not shown) is performed on the flue gas sampling device 1 under the control of the flue gas analysis and control device 6, so that dust blockage is prevented;
each path of flue gas flow velocity pressure-taking device 3 corresponds to a grid partition and is used for obtaining differential pressure signals of the partitioned flue gas flow velocity;
the differential pressure transmitter 5 is used for converting the acquired flue gas flow velocity actual measurement differential pressure signal corresponding to the flow velocity into an electric signal and transmitting the electric signal to the flue gas analysis and control device 6;
each differential pressure transmitter 5 corresponds to one path of pressure taking valve 4;
each pressure-taking valve 4 corresponds to one flue gas flow-rate pressure-taking device 3, obtains flow-rate differential pressure under the control of the flue gas analysis and control device 6, sends flow-rate actual measurement data to the flue gas analysis and control device 6 through the differential pressure transmitter 5, and back blows the flue gas flow-rate pressure-taking device 3 under the control of the flue gas analysis and control device 6 (a conventional back blowing device is adopted, which is not shown in the figure) to prevent dust blockage;
the flue gas analysis and control device 6 performs pretreatment and cyclic alternate analysis on the extracted sampling flue gas to obtain actual measurement data of pollutant components of each partition, and transmits the actual measurement data of pollutant components of each partition and flue gas flow velocity to the server operation processing system 7;
the server operation processing system 7 carries out numerical simulation on the smoke velocity field, the vector field and the pollutant concentration field of each section partition under different working conditions based on unit basic parameters and operation big data from a unit SIS system;
the server operation processing system 7 performs theoretical simulation to obtain theoretical data of a partition speed field, a vector field and a pollutant concentration field under different working conditions, and a large database is established;
the server operation processing system 7 is combined with a large database of the unit flow field to correct the measured value of each subarea flow field under the real-time working condition, and obtains measurement correction data of each subarea speed field, pollutant concentration field, section flue gas flow and pollutant concentration;
and the server operation processing system 7 is combined with measurement correction data to correct a large database of the unit flow field, so as to obtain soft measurement data of each subarea speed field, pollutant concentration field, section flue gas flow and pollutant concentration under real-time working conditions.
The unit big data soft measurement is combined with an online continuous measurement device to form a smoke flow field composite measurement system;
dividing the section of the flue into different grid partitions according to the size of the section of the flue, arranging one flue gas sampling device 1 in each grid partition of the flue, switching and selecting sampling flue gas of a required partition under the control of a flue gas analysis and control device 6, and preprocessing and circularly and alternately analyzing the extracted sampling flue gas to obtain the actual measurement data of pollutant components of each partition; each path of flue gas flow velocity pressure-taking device 3 corresponds to a grid partition, differential pressure signals of the flue gas flow velocities of the partitions are obtained through pressure-taking valves 4, the obtained actual measurement differential pressure signals of the flue gas flow velocities corresponding to the flow velocities are converted into electric signals through differential pressure transmitters 5, and the electric signals are transmitted to a flue gas analysis and control device 6; the flue gas analysis and control device 6 transmits the measured data of the pollutant components and the flue gas flow rate of each partition to the server operation processing system 7. For example: the section size of the flue is 13.5 m long and 3.5 m wide, and then 12 grid partitions are divided according to the length of 2.25 m and the width of 1.75 m.
According to the technical scheme disclosed by the embodiment of the invention, the cross section of the flue is subjected to grid division to obtain a plurality of grid partitions, each grid partition is provided with a sampling device, partition pipelines are selected according to the requirement through sampling valves, and the extracted sample gas is subjected to pretreatment and cyclic alternate analysis to obtain the actual measurement value of the pollutant concentration partition and the distribution data of the pollutant concentration field on the cross section of the flue. Because each grid is internally provided with a sampling device, the defect that the existing denitration device for NOx concentration measurement generally adopts three measuring probes or multipoint mixed sampling and a desulfurization device SO is overcome 2 The concentration measurement usually adopts a measuring probe, and the flue gas flow rate measurement adopts the defect of a multipoint mixing average pressure taking method, so that the pollutant concentration and flue gas flow rate measurement data are more representative and are closer to the actual value of the section of the whole flue. On the basis, the unit basic parameters and the operation big data from the unit SIS system are utilized to carry out numerical simulation on the data of the section partition smoke speed field, the vector field and the pollutant concentration field under different working conditions, theoretical calculation is carried out, a unit flow field big database under different working conditions is established, and the section partition speed field, the vector field, the pollutant concentration field, the section smoke flow and the pollutant concentration soft measurement data are obtained through repeated superposition correction of theoretical calculation data and actual measurement data. The measurement accuracy is further improved through the smoke flow field composite measurement, a basis is provided for the accurate control of pollutants, standard emission is guaranteed, the safety of a unit is improved, and the energy consumption of the pollutants is reduced.
Example two
Corresponding to the composite smoke flow field measurement system based on combination of the unit big data soft measurement and the online continuous measurement device disclosed in the first embodiment of the invention, the second embodiment of the invention also provides a composite smoke flow field measurement method based on combination of the unit big data soft measurement and the online continuous measurement device, referring to fig. 3, the method comprises the following steps:
s11, grid dividing is carried out on the section of the flue according to the size of the section of the flue based on a grid method, so that a plurality of grid partitions are obtained;
s12, carrying out numerical simulation on values of a section partition smoke speed field, a vector field and a pollutant concentration field under different loads by a server operation processing system;
s13, carrying out theoretical simulation by the server operation processing system to obtain theoretical simulation data of a zoned speed field, a vector field and a pollutant concentration field under different working conditions, and establishing a flow field big database;
s14, sampling, preprocessing and circularly measuring the flue gas in the flue subareas to obtain a partitioned actual measurement value of the pollutant concentration of the section of the flue;
s15, simultaneously carrying out zone measurement on the flue gas flow velocity of the flue to obtain a flue gas zone flow velocity actual measurement value;
s16, the server operation processing system combines the numerical simulation theory calculation data, corrects the partition actual measurement value, and gives out measurement correction data of the partition speed field, the pollutant concentration field, the section flue gas flow and the pollutant concentration;
referring to fig. 2, for the flue gas flow velocity pressure-taking device 3, the total pressure PA pressure-taking port is opposite to the flue gas flow velocity V during installation. However, due to the influence of the flue shape, the working condition change of the unit and other factors, the actual flue gas flow velocity deviates from the theoretical flow velocity direction V, and the flow velocity deviation angle is assumed to be theta, namely the flue gas flow velocity positively acting on the PA is V S ，V S For the measured pitot tube differential pressure Pd ' =pa ' -PB ', total pressure =v×cos θWhen the smoke flow velocity V is positive to the Pitot tube pressure-taking port PA, the smoke flow velocity V is positive to the Pitot tube pressure-taking port PA>Thus->Correction coefficient is->In the existing flow velocity measuring device, the angle θ cannot be measured, and correction cannot be performed, so that the measured value tends to be smaller. According to the server operation processing system, based on unit basic parameters and operation big data from a unit SIS system, numerical simulation is carried out on a cross section zoned smoke velocity field, a vector field and a pollutant concentration field under different working conditions, and the position flow velocity deviation angle theta of an actually measured instrument can be obtained, so that the actual measurement value of the smoke flow velocity can be corrected, the measurement precision of an actual measuring instrument is improved, meanwhile, the accuracy of a numerical simulation flow field can be further improved by correcting the actual measurement results of the flow velocity field and the concentration field again (see step S17), and the soft measurement precision of the flue cross section flow field (comprising the flow velocity and the flow direction field) and the concentration field can be further improved through the system for carrying out alternate iterative correction of a plurality of long-time rounds of the unit (carrying out alternate iterative correction of a plurality of long-time rounds of the long-time running of the unit).
S17, the server operation processing system is combined with the measurement correction data to correct the digital simulation data, so as to obtain real-time soft measurement data of the speed field, the pollutant concentration field, the section flue gas flow and the pollutant concentration of each partition;
in the second embodiment of the invention, the cross section of the flue is subjected to grid division to obtain a plurality of grid partitions, each grid partition is provided with a sampling device, partition pipelines are selected according to the requirement through sampling valves, and the extracted sample gas is subjected to pretreatment and cyclic alternate analysis to obtain the actual measurement value of the pollutant concentration partition and the distribution data of the pollutant concentration field on the cross section of the flue. Because each grid is internally provided with a sampling device, the defect that the existing denitration device for NOx concentration measurement generally adopts three measuring probes or multipoint mixed sampling and a desulfurization device SO is overcome 2 The concentration measurement usually adopts a measuring probe, and the flue gas flow rate measurement adopts the defect of a multipoint mixing average pressure taking method, so that the pollutant concentration and flue gas flow rate measurement data are more representative and are closer to the section of the whole flueActual value of the face. On the basis, numerical simulation is carried out on the smoke velocity field, the vector field and the pollutant concentration field of each section under different working conditions by utilizing basic parameters of the unit and operation big data from an SIS system of the unit, a big flow field database under different working conditions is established, and soft measurement data of the velocity field, the vector field, the pollutant concentration field, the section smoke flow and the pollutant concentration of each section under real-time working conditions are obtained by repeatedly superposing and correcting theoretical simulation data and actual measurement data. The measurement accuracy is further improved through the smoke flow field composite measurement, a basis is provided for the accurate control of pollutants, standard emission is guaranteed, the safety of a unit is improved, and the energy consumption of the pollutants is reduced.
In the present specification, each embodiment is described in a progressive manner, and each embodiment is mainly described in a different point from other embodiments, and identical and similar parts between the embodiments are all enough to refer to each other. For the device disclosed in the embodiment, since it corresponds to the method disclosed in the embodiment, the description is relatively simple, and the relevant points refer to the description of the method section. 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 (5)
1. A method for measuring a composite flue gas flow field is characterized by comprising the following steps of: the method comprises the steps of establishing a large unit flow field database under different working conditions through numerical simulation theoretical calculation, correcting measured values, and correcting flow fields and concentration fields under the working conditions in the large unit flow field database by combining measured correction data, so as to obtain smoke data under real-time working conditions; according to the method for measuring the composite flue gas flow field, a plurality of grid partitions are obtained by carrying out grid division on the section of a flue, numerical simulation theoretical calculation is carried out, a large unit flow field database under different working conditions is established, the flow velocity and the pollutant concentration of the flue gas at the section of the flue are measured in real time in a partition mode, real-time measurement data are corrected through theoretical simulation data of the large unit flow field database, and flow fields and concentration fields under the working conditions in the large unit flow field database are corrected through combining actual measurement correction data, so that flue gas data under the real-time working conditions are obtained; theoretical simulation data of the large database of the unit flow field comprises a flue section speed field, a flow direction vector field and a pollutant concentration field;
the obtained flue gas data under the real-time working condition comprises a flue section speed field, a vector field, a pollutant concentration field and section flue gas flow and pollutant concentration soft measurement data;
the method for measuring the composite flue gas flow field comprises the following steps:
s11, grid dividing is carried out on the section of the flue according to the size of the section of the flue based on a grid method, so that a plurality of grid partitions are obtained;
s12, carrying out numerical simulation on values of the section partition flue gas velocity field, the vector field and the pollutant concentration field under different loads;
s13, carrying out theoretical simulation to obtain theoretical simulation data of a zoned speed field, a vector field and a pollutant concentration field under different working conditions, and establishing a flow field big database;
s14, sampling, preprocessing and circularly measuring the flue gas in the flue subareas to obtain a partitioned actual measurement value of the pollutant concentration of the cross section of the flue;
s15, simultaneously carrying out zone measurement on the flue gas flow velocity of the flue to obtain a flue gas zone flow velocity actual measurement value;
s16, combining numerical simulation theory calculation data, correcting the partition actual measurement value, and giving measurement correction data of the partition flow velocity field, the pollutant concentration field, the section flue gas flow and the pollutant concentration;
s17, correcting a large database of a unit flow field by combining measurement correction data to obtain real-time soft measurement data of each partition speed field, pollutant concentration field, section flue gas flow and pollutant concentration;
in the step S16, the correction of the partition measured value at least includes correction of the flow vector field to the measured value of the flow velocity of the flue gas, correction of the flow field large database of the flow vector field, the flow velocity field and the concentration field to the measured flow velocity field and the measured pollutant concentration field, and the correction process includes both rejection and correction of the measured abnormal value which does not accord with the theoretical calculation and correction of the influence of the deviation of the flow direction and the ideal flow direction on the measuring instrument;
the specific method for correcting the flue gas flow velocity measurement value by the flow direction vector field comprises the following steps: and combining numerical simulation theory calculation data to obtain an actual measurement flow velocity deviation angle, so as to correct the actual measurement value of the flue gas flow velocity, and further correct the flue gas flow velocity field and the pollutant concentration field.
2. A measurement system employing the composite flue gas flow field measurement method of claim 1, the measurement system being for grid-zoned flue section, characterized by: the system comprises a plurality of paths of flue gas sampling devices which are in one-to-one correspondence with grid partitions, a plurality of paths of flue gas flow rate measuring devices which are in one-to-one correspondence with the grid partitions, a flue gas analysis and control device and a server operation processing system; the flue gas analysis and control device is respectively connected with each flue gas sampling device and each flue gas flow rate measuring device; the server operation processing system is respectively connected with the flue gas analysis and control device and the unit SIS system.
3. The measurement system according to claim 2, wherein: the flue gas flow velocity measuring device comprises a flue gas flow velocity pressure measuring device, a pressure measuring valve and a differential pressure transmitter which are connected in sequence.
4. A measurement system according to claim 3, wherein: the measurement system includes:
the multi-channel flue gas sampling device is respectively in one-to-one correspondence with each grid partition, samples the flue gas and sends the flue gas into the flue gas analysis and control device through the corresponding sampling valve;
the multi-channel flue gas flow velocity pressure-taking device is respectively in one-to-one correspondence with each grid partition, obtains flow velocity differential pressure and sequentially sends the flow velocity differential pressure into the flue gas analysis and control device through the corresponding pressure-taking valve and the differential pressure transmitter;
the flue gas analysis and control device is controlled to be connected with each sampling valve and each pressure-taking valve, receives the sampled flue gas of each flue gas sampling device and the measured data of each flue gas flow speed pressure-taking device, analyzes and processes the sampled flue gas to obtain corresponding pollutant components and the measured data of the flue gas flow speed, and transmits the corresponding pollutant components and the measured data of the flue gas flow speed to the server operation processing system;
and the server operation processing system receives the data of the flue gas analysis and control device, and obtains the required flue gas data after superposition correction.
5. The measurement system of claim 4, wherein: the server operation processing system is in control connection with the unit SIS system, basic parameters and operation big data of the unit are obtained, numerical simulation is carried out on the flue section flue gas speed field, the vector field and the pollutant concentration field under each working condition, theoretical data of the flue section speed field, the flue gas flow direction vector field and the pollutant concentration field under different working conditions are obtained, and a unit flow field big database is established.
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