CN110090552B - SCR denitration automatic ammonia injection optimization adjustment system and adjustment method thereof - Google Patents
SCR denitration automatic ammonia injection optimization adjustment system and adjustment method thereof Download PDFInfo
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- CN110090552B CN110090552B CN201910268636.7A CN201910268636A CN110090552B CN 110090552 B CN110090552 B CN 110090552B CN 201910268636 A CN201910268636 A CN 201910268636A CN 110090552 B CN110090552 B CN 110090552B
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- QGZKDVFQNNGYKY-UHFFFAOYSA-N Ammonia Chemical compound N QGZKDVFQNNGYKY-UHFFFAOYSA-N 0.000 title claims abstract description 155
- 229910021529 ammonia Inorganic materials 0.000 title claims abstract description 76
- 238000002347 injection Methods 0.000 title claims abstract description 49
- 239000007924 injection Substances 0.000 title claims abstract description 49
- 238000000034 method Methods 0.000 title claims abstract description 27
- 238000005457 optimization Methods 0.000 title claims description 26
- 239000003054 catalyst Substances 0.000 claims abstract description 117
- 238000005259 measurement Methods 0.000 claims abstract description 30
- UGFAIRIUMAVXCW-UHFFFAOYSA-N Carbon monoxide Chemical compound [O+]#[C-] UGFAIRIUMAVXCW-UHFFFAOYSA-N 0.000 claims abstract description 20
- 238000004364 calculation method Methods 0.000 claims abstract description 20
- 239000003546 flue gas Substances 0.000 claims abstract description 20
- 239000007789 gas Substances 0.000 claims abstract description 8
- MWUXSHHQAYIFBG-UHFFFAOYSA-N nitrogen oxide Inorganic materials O=[N] MWUXSHHQAYIFBG-UHFFFAOYSA-N 0.000 claims description 84
- CURLTUGMZLYLDI-UHFFFAOYSA-N Carbon dioxide Chemical compound O=C=O CURLTUGMZLYLDI-UHFFFAOYSA-N 0.000 claims description 18
- RAHZWNYVWXNFOC-UHFFFAOYSA-N Sulphur dioxide Chemical compound O=S=O RAHZWNYVWXNFOC-UHFFFAOYSA-N 0.000 claims description 18
- 238000005507 spraying Methods 0.000 claims description 18
- 239000000779 smoke Substances 0.000 claims description 16
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 claims description 15
- 229910052760 oxygen Inorganic materials 0.000 claims description 15
- 239000001301 oxygen Substances 0.000 claims description 15
- 230000003068 static effect Effects 0.000 claims description 10
- 229910002092 carbon dioxide Inorganic materials 0.000 claims description 9
- 239000001569 carbon dioxide Substances 0.000 claims description 9
- 238000009434 installation Methods 0.000 claims description 8
- 238000001816 cooling Methods 0.000 claims description 7
- 238000010926 purge Methods 0.000 claims description 7
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 claims description 6
- 230000000149 penetrating effect Effects 0.000 claims description 5
- 229910052757 nitrogen Inorganic materials 0.000 claims description 3
- 238000005070 sampling Methods 0.000 abstract description 8
- 238000004458 analytical method Methods 0.000 abstract description 2
- 239000003344 environmental pollutant Substances 0.000 description 3
- 231100000719 pollutant Toxicity 0.000 description 3
- 238000005299 abrasion Methods 0.000 description 2
- 238000001514 detection method Methods 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 238000005516 engineering process Methods 0.000 description 2
- BIGPRXCJEDHCLP-UHFFFAOYSA-N ammonium bisulfate Chemical compound [NH4+].OS([O-])(=O)=O BIGPRXCJEDHCLP-UHFFFAOYSA-N 0.000 description 1
- 238000000738 capillary electrophoresis-mass spectrometry Methods 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 238000013461 design Methods 0.000 description 1
- 230000002779 inactivation Effects 0.000 description 1
- 230000007774 longterm Effects 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000012544 monitoring process Methods 0.000 description 1
- 229910000069 nitrogen hydride Inorganic materials 0.000 description 1
- 238000012545 processing Methods 0.000 description 1
- 239000000523 sample Substances 0.000 description 1
- 239000007921 spray Substances 0.000 description 1
Classifications
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
- B01D53/34—Chemical or biological purification of waste gases
- B01D53/74—General processes for purification of waste gases; Apparatus or devices specially adapted therefor
- B01D53/86—Catalytic processes
- B01D53/8621—Removing nitrogen compounds
- B01D53/8625—Nitrogen oxides
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D2251/00—Reactants
- B01D2251/20—Reductants
- B01D2251/206—Ammonium compounds
- B01D2251/2062—Ammonia
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- Engineering & Computer Science (AREA)
- Environmental & Geological Engineering (AREA)
- Chemical & Material Sciences (AREA)
- Health & Medical Sciences (AREA)
- Biomedical Technology (AREA)
- Analytical Chemistry (AREA)
- General Chemical & Material Sciences (AREA)
- Oil, Petroleum & Natural Gas (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Exhaust Gas Treatment By Means Of Catalyst (AREA)
Abstract
The invention relates to an automatic ammonia injection optimizing and adjusting system for SCR denitration and an adjusting method thereof, wherein a set of measuring pipe network, a telescopic thermometer and a telescopic dynamic pressure measuring instrument are arranged above a first layer of catalyst, between the first layer of catalyst and a second layer of catalyst, between the second layer of catalyst and a third layer of catalyst and below the third layer of catalyst, each set of measuring pipe network comprises a measuring main pipe, the measuring main pipe penetrates into a denitration flue and is branched into a plurality of paths of auxiliary pipes, each path of auxiliary pipe is uniformly branched into a plurality of paths of branch pipes, the measuring pipe network is arranged in a grid method for multi-point sampling measurement, so that the sampling analysis of the flue gas at an inlet and an outlet of each layer of catalyst is realized, the temperature, the pressure, the flow velocity and the gas distribution data of each component are obtained, the ammonia injection quantity of each branch pipe is determined through the arrangement and the calculation of the data, and the ammonia injection quantity of each branch pipe is automatically adjusted, meanwhile, the running condition of each module of each layer of catalyst is recorded, and the basis is provided for the replacement of the catalyst.
Description
Technical Field
The invention relates to the technical field of control of atmospheric pollutants of coal-fired boilers, in particular to an SCR denitration automatic ammonia injection optimization adjustment system and an adjustment method thereof.
Background
With the increasing severity of the atmospheric pollutants, the emission control of the atmospheric pollutants NOX in thermal power enterprises is also becoming more and more strict. In order to achieve the purpose of controlling NOX emission, SCR denitration technology is introduced. The SCR denitration technology is characterized in that ammonia gas and nitrogen oxides are sprayed to perform chemical reaction under the condition of a catalyst, so that NOX in the flue gas can be removed efficiently. However, due to the influence of factors such as the uniformity of the distribution of the smoke flow field and components, the abrasion of the catalyst, the inactivation of the catalyst and the like, the denitration efficiency can not meet the design requirement, excessive ammonia injection or uneven ammonia injection is further caused, finally, the NOX emission is not effectively controlled, and meanwhile, the generation of ammonium bisulfate can be caused, so that the tail equipment of a flue is damaged. In order to avoid the occurrence of the situation, the ammonia injection optimization adjustment is required to be carried out frequently, but the existing adjustment modes only can ensure the denitration efficiency under certain specific working conditions, and do not have real-time performance and long-term performance.
Chinese patent application No. 2015101046986, grant publication No. CN 104699061B: an SCR denitration catalyst online detection and ammonia injection optimization control method utilizes the existing measuring points of a CEMS system to carry out automatic ammonia injection optimization adjustment, and can judge the condition of catalyst performance reduction, but the problem of uneven ammonia injection cannot be solved because the measuring points are fixed and the measuring positions are few.
Chinese patent application No. 2015105145209, grant publication No. CN 105126616B: the ammonia injection optimizing method disclosed in the patent can measure the flow velocity distribution condition of the flue gas in operation, but cannot measure the NOX concentration distribution condition, and the ammonia injection optimizing method based on weight valve regulation and control can not adjust the operation effect of the SCR system in real time by using a manual measuring method.
Chinese patent application No. 2016102313885, grant publication No. CN 105854597B: according to the intelligent optimization adjustment system and method for the ammonia spraying grid of the SCR denitration device, detection on NH3 and NOX concentration distribution at an inlet of a denitration catalyst and NOX concentration distribution at an outlet of the denitration catalyst can be achieved, optimal ammonia spraying amount is obtained through calculation of an intelligent control system, an ammonia spraying branch pipe is adjusted, and finally the aim of optimal ammonia spraying adjustment is achieved conveniently, accurately and quickly.
In view of this, there is a need for improvements in existing SCR denitration automatic ammonia injection optimization adjustment systems and methods.
Disclosure of Invention
The invention aims to overcome the defects in the prior art and provide an automatic ammonia injection optimization adjustment system and an adjustment method thereof, wherein the automatic ammonia injection optimization adjustment system can be accurate, quick and real-time according to the arrangement characteristics and the operation characteristics of an SCR denitration system.
The invention solves the problems by adopting the following technical scheme: the automatic ammonia spraying optimization adjustment system for SCR denitration comprises a denitration flue, a first layer of catalyst, a second layer of catalyst, a third layer of catalyst and an ammonia spraying grid, wherein the first layer of catalyst, the second layer of catalyst and the third layer of catalyst are arranged from top to bottom, and the ammonia spraying grid is positioned above the first layer of catalyst; the method is characterized in that: a set of measuring pipe network, a telescopic thermometer and a telescopic dynamic pressure measuring instrument are arranged above the first layer of catalyst, between the first layer of catalyst and the second layer of catalyst, between the second layer of catalyst and the third layer of catalyst and below the third layer of catalyst, wherein the measuring pipe network arranged above the first layer of catalyst is positioned below the ammonia injection grid; each set of measurement pipe network comprises a measurement main pipe, the measurement main pipe penetrates into the denitration flue and is branched into a plurality of auxiliary pipes, the auxiliary pipes are positioned in the same horizontal plane and are distributed at equal intervals, each auxiliary pipe is equally branched with a plurality of branch pipes which are positioned in the same vertical plane and are distributed at equal intervals from top to bottom in the height direction, the horizontal lengths of the branch pipes of each auxiliary pipe are sequentially reduced from top to bottom in equal difference, namely, the horizontal length of the branch pipe positioned at the uppermost part is longest, and the horizontal length of the branch pipe positioned at the lowermost part is shortest; the end parts of the branch pipes are provided with measuring holes, and each branch pipe is provided with a branch pipe electric valve; the measuring main pipe of the denitration flue is provided with a pressure gauge, a flue gas analyzer and an ammonia concentration detector which are connected, and the pressure gauge is provided with a main pipe electric valve.
Preferably, the measuring main pipe penetrating out of the denitration flue is connected with a compressed air inlet pipeline, and a purging valve is arranged on the compressed air inlet pipeline.
Preferably, the telescopic thermometer and the telescopic dynamic pressure measuring instrument are installed through telescopic pipelines; the telescopic pipeline is arranged outside the denitration flue, and one end of the telescopic pipeline is communicated and connected with the denitration flue; the outside of the telescopic pipeline is provided with a steam cooling protection device; the telescopic pipeline for installing the telescopic thermometer and the telescopic pipeline for installing the telescopic dynamic pressure measuring instrument can share one set of steam cooling protection device, and two sets of steam cooling devices can be used respectively.
Preferably, the first layer of catalyst, the second layer of catalyst and the third layer of catalyst have the same structure, and are all composed of M rows and N columns of catalyst mounting modules; the number of the branch pipes of each branch pipe is equal to the number of M lines, the number of the branch pipes of each branch pipe is equal to the number of N columns, the total number of the branch pipes in each set of measuring pipe network is equal to the product of the number of M lines and the number of N columns, the branch pipes are in one-to-one correspondence with the catalyst installation modules, the measuring pipe network presents a grid method arrangement mode, and the measuring surface can cover the section of the whole flue gas flow field; each branch pipe is a sampling point, and the sampling points are dense enough to cover the whole flue section.
Preferably, the first layer of catalyst, the second layer of catalyst and the third layer of catalyst are all composed of five rows and seven columns of catalyst installation modules, namely each set of measurement pipe network comprises 5 paths of auxiliary pipes and 35 paths of branch pipes.
In order to solve the technical problems, the invention also provides another technical scheme: an adjusting method of an SCR denitration automatic ammonia injection optimizing and adjusting system is set as follows: the outlet concentration of nitrogen oxides is used as the outlet condition, and the outlet concentration of nitrogen oxides is 50mg/m 3 Is a limit value; the measuring pipe network above the first layer of catalyst is a first set of measuring pipe network, the measuring pipe network between the first layer of catalyst and the second layer of catalyst is a second set of measuring pipe network, the measuring pipe network between the second layer of catalyst and the third layer of catalyst is a third set of measuring pipe network, and the measuring pipe network below the third layer of catalyst is a fourth set of measuring pipe network.
The adjusting method comprises the following specific steps:
the first step: sequentially opening branch pipe electric valves installed on 35 branch pipes in first set of measuring pipe network, and using smoke in the set of measuring pipe networkGas analyzer, ammonia concentration detector and pressure gauge for measuring nitrogen oxide inlet concentration average value NO X inlet Average value O of oxygen concentration 2 inlet Average value of carbon dioxide concentration CO 2 inlet Average SO of sulfur dioxide concentration 2 inlet Average NH of ammonia concentration 3 inlet And an average value of inlet static pressure P An inlet Simultaneously, a telescopic thermodetector and a telescopic dynamic pressure measuring instrument which are arranged above the first layer of catalyst are used for respectively measuring the average value T of the inlet temperature An inlet And an inlet dynamic pressure DeltaP An inlet Then calculating according to a formula to obtain the theoretical ammonia injection quantity w 1 ；
Theoretical ammonia injection amount w 1 The calculation formula of (2) is as follows:
wherein: theoretical ammonia injection amount w 1 Is in kg/h; η is denitration efficiency,%; q (Q) 0 In the form of standard state, dry basis and the smoke quantity under the actual oxygen content, m 3 /h；NO X inlet Is the average value of the concentration of nitrogen oxides at the denitration inlet.
The calculation formula of eta is as follows:
wherein: NO (NO) X outlet For the average value of the concentration of the nitrogen oxide at the denitration outlet, 50mg/m is taken 3 。
Q 0 The calculation formula of (2) is as follows:
wherein: q (Q) w For denitration inlet standard state, wet basis and smoke quantity under actual oxygen content, m 3 /h；T An inlet Is the average temperature of a denitration inlet, and is at the temperature of DEG C; p (P) An inlet The average static pressure Pa of a denitration inlet; b (B) a Atmospheric pressure, pa; theta is smokeMoisture content of gas,%.
Q w The calculation formula of (2) is as follows:
Q w ＝3600×S×V i
wherein: s is the measured sectional area, m 2 ；V i To measure the speed of the i-point, m/s.
V i The calculation formula of (2) is as follows:
wherein: k is the backrest tube coefficient, and 0.84 is taken; deltaP An inlet To measure the dynamic pressure of point i, pa; ρ is standard state, wet-base smoke density, kg/m 3 。
The calculation formula of ρ is:
wherein: o (O) 2 inlet The dry oxygen volume percent in the flue gas is,%;
CO 2 inlet The volume percent of the dry carbon dioxide gas in the flue gas is percent;
SO 2 inlet The volume percent of dry sulfur dioxide gas in the flue gas is percent;
1.4286kg/m of oxygen density of standard state and wet base 3 ；
1.9643kg/m of standard state and wet carbon dioxide density 3 ；
2.8580kg/m of standard state and wet-base sulfur dioxide density 3 ；
0.8036kg/m of the standard state and wet base steam density 3 ；
1.2507kg/m of standard state and wet nitrogen density 3 ；
And a second step of: sequentially opening branch pipe electric valves arranged on 35 branch pipes in a fourth set of measuring pipe network to measure the average NO of the concentration of the nitrogen oxide outlet X outlet Average value of static pressure at outlet P An outlet And an average value T of the outlet temperature An outlet Then correcting the theoretical ammonia spraying amount obtained by the calculation in the first step to obtain the ammonia spraying amount w 2 ；
And a third step of: when NO X outlet Less than 50mg/m 3 Relative standard deviation D An outlet When the ammonia injection optimization adjustment is less than 10 percent, ending; when D is An outlet When the concentration deviation of the nitrogen oxides is more than 10%, adjusting the ammonia spraying grids corresponding to the positions with larger concentration deviation of the nitrogen oxides until NO X outlet Less than 50mg/m 3 And D is An outlet Less than 10%;
fourth step: measuring the concentration, temperature and pressure of nitrogen oxides at the inlet and the outlet of each catalyst installation module by using four sets of measuring pipe networks, respectively calculating the denitration efficiency of each module, recording data, analyzing the running condition of the module, and providing a basis for replacing the catalyst;
fifth step: and opening a purging valve, and using compressed air to self-clean the measurement pipe network.
Compared with the prior art, the invention has the following advantages and effects:
1) The real-time and continuous adjustment of ammonia injection optimization is realized, the limitation of the load working condition is avoided, the measuring pipe network is arranged in the denitration flue, parameters such as smoke components and the like can be measured in real time, and the adjustment of the ammonia injection amount is realized without the limitation of the load working condition;
2) The intelligent adjustment of ammonia injection optimization is realized, manual operation is greatly reduced, and the automatic control system is used for automatically processing data, so that the manual operation is greatly reduced;
3) Accurate measurement of smoke components and static pressure is realized, and the measuring surface can cover the section of the whole smoke flow field; the measuring pipe network is arranged in the flue by a grid method, and sampling points are dense enough to cover the section of the whole flue;
4) The monitoring of the running state of each layer of catalyst is realized, a measuring pipe network is arranged at the upper part and the lower part of each layer of catalyst, the inlet and outlet parameters of each layer of catalyst can be sampled in real time and recorded, a database is built for the performance parameters of each catalyst, and data support is provided for the performance analysis and replacement of the catalyst;
5) The temperature and dynamic pressure are measured by the telescopic thermometer and the telescopic dynamic pressure measuring instrument, the measuring gun is flexible and quick, the total amount of the measuring probe is reduced on the premise that the sampling points are enough, and the abrasion of the instrument in a flue is effectively avoided.
Drawings
Fig. 1 is a schematic diagram of a front view structure of an embodiment of the present invention.
Fig. 2 is a top plan view schematically depicting a second set of measurement network in an embodiment of the present invention.
Fig. 3 is a distribution structure diagram schematically illustrating a distribution of 7 branch pipes of a secondary pipe branch in a second set of measurement pipe network in the height direction from a main view angle in the embodiment of the present invention.
In the figure:
a first layer of catalyst 1, a second layer of catalyst 2, and a third layer of catalyst 3;
denitration flue 4, ammonia injection grid 5, flue gas analyzer 6, ammonia concentration detector 7, and catalyst installation die 8;
a pressure gauge 21, an electric valve 210, a compressed air inlet pipeline 15 and a purge valve 9;
a first set of measuring manifolds 11 of the measuring network;
a second set of measuring manifolds 12 of the measuring network;
a third set of measuring pipe network measuring header 13;
a fourth set of measuring manifolds 14 of the measuring network;
5-way secondary pipes 121, 122, 123, 124 and 125 branched by the main pipe 12 are measured;
7-way branch pipes 1251, 1252, 1253, 1254, 1255, 1256, 1257 branched from the sub-pipe 125;
a manifold electrically operated valve 12571 is mounted on manifold 1257.
Detailed Description
The present invention will be described in further detail by way of examples with reference to the accompanying drawings, which are illustrative of the present invention and not limited to the following examples.
Examples
See fig. 1-3.
The embodiment is an automatic ammonia injection optimization adjustment system for SCR denitration, which comprises a denitration flue 4, a first layer of catalyst 1, a second layer of catalyst 2, a third layer of catalyst 3 and an ammonia injection grid 5 which are arranged in the denitration flue 4, wherein the first layer of catalyst 1, the second layer of catalyst 2 and the third layer of catalyst 3 are arranged from top to bottom, and the ammonia injection grid 5 is positioned above the first layer of catalyst 1.
In this embodiment, a set of measuring pipe network, a telescopic thermometer 88 and a telescopic dynamic pressure measuring instrument 99 are arranged above the first layer of catalyst 1, between the first layer of catalyst 1 and the second layer of catalyst 2, between the second layer of catalyst 2 and the third layer of catalyst 3 and below the third layer of catalyst 3. Setting: the measuring pipe network above the first layer catalyst 1 is a first set of measuring pipe network, the measuring pipe network between the first layer catalyst 1 and the second layer catalyst 2 is a second set of measuring pipe network, the measuring pipe network between the second layer catalyst 2 and the third layer catalyst 3 is a third set of measuring pipe network, and the measuring pipe network below the third layer catalyst 3 is a fourth set of measuring pipe network. The first set of measuring pipe network is located below the ammonia injection grid 5.
In this embodiment, each set of measurement pipe networks has the same structure and includes a measurement manifold, and referring to fig. 1, reference numeral 11 in the drawing indicates a measurement manifold of a first set of measurement pipe networks, reference numeral 12 in the drawing indicates a measurement manifold of a second set of measurement pipe networks, reference numeral 13 in the drawing indicates a measurement manifold of a third set of measurement pipe networks, and reference numeral 14 in the drawing indicates a measurement manifold of a fourth set of measurement pipe networks.
Taking a second set of measuring pipe network as an example, the structure of the measuring pipe network is described, referring to fig. 2 and 3, the measuring main pipe 12 penetrates into the denitration flue 4 to branch into 5 paths of auxiliary pipes 121, 122, 123, 124 and 125, the 5 paths of auxiliary pipes are located in the same horizontal plane and are arranged at equal intervals, each path of auxiliary pipe is equally divided into 7 paths of branch pipes located in the same vertical plane and are arranged at equal intervals from top to bottom in the height direction, the horizontal lengths of the 7 paths of branch pipes on each path of auxiliary pipe are sequentially equal-progressively decreased from top to bottom, namely, the horizontal length of the branch pipe located at the uppermost position is longest, and the horizontal length of the branch pipe located at the lowermost position is shortest. For example, fig. 3 shows a schematic distribution structure of 7 branch pipes branched from the secondary pipe 125, and the 7 branch pipes are 1251, 1252, 1253, 1254, 1255, 1256, and 1257 from top to bottom. The end part of each branch pipe is provided with a measuring hole, and each branch pipe is provided with a branch pipe electric valve; for example, a manifold electrically operated valve 12571 is mounted to the manifold 1257.
The measurement pipe network is designed to be in a grid method arrangement mode and is matched with a three-layer catalyst structure mode, and in the embodiment, the first layer of catalyst 1, the second layer of catalyst 2 and the third layer of catalyst 3 are of the same structure and are composed of five rows and seven columns of catalyst mounting modules 8; the number of the branch pipes of each set of the measuring pipe network is equal to the product of the total number of the branch pipes of each set of the measuring pipe network and the number of the lines and the number of the columns, namely, the total number of the branch pipes is 35, and the branch pipes are in one-to-one correspondence with the catalyst mounting modules 8, so that the measuring surface of the measuring pipe network can cover the section of the whole flue gas flow field; each branch pipe is a sampling point, and the sampling points are dense enough to cover the whole flue section.
In this embodiment, a pressure gauge 21, a flue gas analyzer 6 and an ammonia concentration detector 7 are installed on a measurement header 11 penetrating out of the denitration flue 4, and a header electric valve 210 is installed on the pressure gauge 21. The measuring main pipe penetrating out of the denitration flue 4 is connected with a compressed air inlet pipeline 15, and a purge valve 9 is arranged on the compressed air inlet pipeline 15.
In this embodiment, the telescopic thermo detector 88 and the telescopic dynamic pressure measuring instrument 99 are installed through telescopic pipes; the telescopic pipeline is arranged outside the denitration flue 4, and one end of the telescopic pipeline is communicated and connected with the denitration flue 4. The outside of the telescopic pipeline is provided with a steam cooling protection device; the telescopic pipeline for installing the telescopic thermometer and the telescopic pipeline for installing the telescopic dynamic pressure measuring instrument can share one set of steam cooling protection device, and two sets of steam cooling devices can be used respectively. As for the specific structure of the telescopic pipe and the structures and mounting manners of the telescopic thermo-detector 88 and the telescopic dynamic pressure measuring instrument 99, reference is made to the prior art.
In this embodiment, the adjustment method of the automatic ammonia injection optimization adjustment system for SCR denitration includes: setting: the outlet concentration of nitrogen oxides is used as the outlet condition, and the outlet concentration of nitrogen oxides is 50mg/m 3 Is a limit value;
the first step: sequentially opening branch pipe electric valves arranged on 35 branch pipes in a first set of measurement pipe network, and measuring nitrogen oxide inlet concentration average value NO by using a smoke analyzer, an ammonia concentration detector and a pressure gauge in the first set of measurement pipe network X inlet Average value O of oxygen concentration 2 inlet Average value of carbon dioxide concentration CO 2 inlet Average SO of sulfur dioxide concentration 2 inlet Average NH of ammonia concentration 3 inlet And an average value of inlet static pressure P An inlet Simultaneously, the average value T of the inlet temperature is measured by a telescopic thermometer and a telescopic dynamic pressure measuring instrument which are arranged above the first layer of catalyst 1 An inlet And an inlet dynamic pressure DeltaP An inlet Then calculating according to a formula to obtain the theoretical ammonia injection quantity w 1 ；
Theoretical ammonia injection amount w 1 The calculation formula of (2) is as follows:
wherein: theoretical ammonia injection amount w 1 Is in kg/h; η is denitration efficiency,%; q (Q) 0 In the form of standard state, dry basis and the smoke quantity under the actual oxygen content, m 3 /h；NO X inlet For denitration inlet nitrogen oxide concentrationAverage value.
The calculation formula of eta is as follows:
wherein: NO (NO) X outlet For the average value of the concentration of the nitrogen oxide at the denitration outlet, 50mg/m is taken 3 。
Q 0 The calculation formula of (2) is as follows:
wherein: q (Q) w For denitration inlet standard state, wet basis and smoke quantity under actual oxygen content, m 3 /h；T An inlet Is the average temperature of a denitration inlet, and is at the temperature of DEG C; p (P) An inlet The average static pressure Pa of a denitration inlet; b (B) a Atmospheric pressure, pa; θ is the moisture content of the flue gas,%.
Q w The calculation formula of (2) is as follows:
Q w ＝3600×S×V i
wherein: s is the measured sectional area, m 2 ；V i To measure the speed of the i-point, m/s.
V i The calculation formula of (2) is as follows:
wherein: k is the backrest tube coefficient, and 0.84 is taken; deltaP An inlet To measure the dynamic pressure of point i, pa; ρ is standard state, wet-base smoke density, kg/m 3 。
The calculation formula of ρ is:
wherein: o (O) 2 inlet The dry oxygen volume percent in the flue gas is,%;
CO 2 inlet The volume percent of the dry carbon dioxide gas in the flue gas is percent;
SO 2 inlet The volume percent of dry sulfur dioxide gas in the flue gas is percent;
1.4286kg/m of oxygen density of standard state and wet base 3 ；
1.9643kg/m of standard state and wet carbon dioxide density 3 ；
2.8580kg/m of standard state and wet-base sulfur dioxide density 3 ；
0.8036kg/m of the standard state and wet base steam density 3 ；
1.2507kg/m of standard state and wet nitrogen density 3 ；
And a second step of: sequentially opening branch pipe electric valves arranged on 35 branch pipes in a fourth set of measuring pipe network to measure the average NO of the concentration of the nitrogen oxide outlet X outlet Average value of static pressure at outlet P An outlet And an average value T of the outlet temperature An outlet Then correcting the theoretical ammonia spraying amount obtained by the calculation in the first step to obtain the ammonia spraying amount w 2 ；
And a third step of: when NO X outlet Less than 50mg/m 3 Relative standard deviation D An outlet When the ammonia injection optimization adjustment is less than 10 percent, ending; when D is An outlet When the concentration deviation of the nitrogen oxide is more than 10%, the corresponding spray at the position with larger concentration deviation of the nitrogen oxide is adjustedAmmonia grids up to NO X outlet Less than 50mg/m 3 And D is An outlet Less than 10%;
fourth step: measuring the concentration, temperature and pressure of nitrogen oxides at the inlet and the outlet of each catalyst installation module by using four sets of measuring pipe networks, respectively calculating the denitration efficiency of each module, recording data, analyzing the running condition of the module, and providing a basis for replacing the catalyst;
fifth step: the purge valve 9 is opened and the measurement pipe network is self-cleaned by compressed air.
Although the present invention is described with reference to the above embodiments, it should be understood that the invention is not limited to the embodiments described above, but is capable of modification and variation without departing from the spirit and scope of the present invention.
Claims (9)
1. The automatic ammonia spraying optimization adjustment system for SCR denitration comprises a denitration flue, a first layer of catalyst, a second layer of catalyst, a third layer of catalyst and an ammonia spraying grid, wherein the first layer of catalyst, the second layer of catalyst and the third layer of catalyst are arranged from top to bottom, and the ammonia spraying grid is positioned above the first layer of catalyst;
the method is characterized in that: a set of measuring pipe network, a telescopic thermometer and a telescopic dynamic pressure measuring instrument are arranged above the first layer of catalyst, between the first layer of catalyst and the second layer of catalyst, between the second layer of catalyst and the third layer of catalyst and below the third layer of catalyst, wherein the measuring pipe network arranged above the first layer of catalyst is positioned below the ammonia injection grid;
each set of measurement pipe network comprises a measurement main pipe, the measurement main pipe penetrates into the denitration flue to be branched into a plurality of auxiliary pipes, the auxiliary pipes are positioned in the same horizontal plane and are distributed at equal intervals, each auxiliary pipe is equally branched with a plurality of branch pipes which are positioned in the same vertical plane and are distributed at equal intervals from top to bottom in the height direction, the horizontal lengths of the branch pipes of each auxiliary pipe are gradually reduced from top to bottom in an equal difference manner, namely, the horizontal length of the branch pipe positioned at the uppermost part is longest, and the horizontal length of the branch pipe positioned at the lowermost part is shortest; the end parts of the branch pipes are provided with measuring holes, and each branch pipe is provided with a branch pipe electric valve; a pressure gauge, a flue gas analyzer and an ammonia concentration detector are arranged on a measuring main pipe penetrating out of the denitration flue, and a main pipe electric valve is arranged on the pressure gauge;
the measuring main pipe penetrating out of the denitration flue is connected with a compressed air inlet pipeline, and a purging valve is arranged on the compressed air inlet pipeline;
the telescopic thermometer and the telescopic dynamic pressure measuring instrument are installed through telescopic pipelines.
2. The SCR denitration automatic ammonia injection optimization adjusting system according to claim 1, wherein: the telescopic pipeline is arranged outside the denitration flue, and one end of the telescopic pipeline is communicated and connected with the denitration flue; and the outside of the telescopic pipeline is provided with a steam cooling protection device.
3. The SCR denitration automatic ammonia injection optimization adjusting system according to claim 1, wherein: the first layer of catalyst, the second layer of catalyst and the third layer of catalyst have the same structure and are composed of M rows and N columns of catalyst mounting modules; the number of the branch pipes of each branch pipe is equal to the number of M lines, the number of the branch pipes of each branch pipe is equal to the number of N columns, the total number of the branch pipes in each set of measuring pipe network is equal to the product of the number of M lines and the number of N columns, and the branch pipes are in one-to-one correspondence with the catalyst installation modules.
4. The SCR denitration automatic ammonia injection optimization adjusting system according to claim 3, wherein: the first layer of catalyst, the second layer of catalyst and the third layer of catalyst are all composed of five-row seven-column catalyst installation modules, namely each set of measuring pipe network comprises 5 paths of auxiliary pipes and 35 paths of branch pipes.
5. An adjustment method of an SCR denitration automatic ammonia injection optimizing adjustment system according to any one of claims 1 to 4, wherein:
setting:
the outlet concentration of nitrogen oxides is used as the outlet condition, and the outlet concentration of nitrogen oxides is 50mg/m 3 Is a limit value;
the measuring pipe network above the first layer of catalyst is a first set of measuring pipe network,
the measuring pipe network between the first layer of catalyst and the second layer of catalyst is a second set of measuring pipe network,
the measuring pipe network between the second layer of catalyst and the third layer of catalyst is a third set of measuring pipe network,
the measuring pipe network below the third layer of catalyst is a fourth set of measuring pipe network;
the adjusting method comprises the following specific steps:
the first step: sequentially opening branch pipe electric valves arranged on 35 branch pipes in a first set of measurement pipe network, and measuring nitrogen oxide inlet concentration average value NO by using a smoke analyzer, an ammonia concentration detector and a pressure gauge in the first set of measurement pipe network X inlet Average value O of oxygen concentration 2 inlet Average value of carbon dioxide concentration CO 2 inlet Average SO of sulfur dioxide concentration 2 inlet Average NH of ammonia concentration 3 inlet And an average value of inlet static pressure P An inlet Simultaneously, a telescopic thermodetector and a telescopic dynamic pressure measuring instrument which are arranged above the first layer of catalyst are used for respectively measuring the average value T of the inlet temperature An inlet And an inlet dynamic pressure DeltaP An inlet Then calculating according to a formula to obtain the theoretical ammonia injection quantity w 1 ；
And a second step of: sequentially opening branch pipe electric valves arranged on 35 branch pipes in a fourth set of measuring pipe network to measure the average NO of the concentration of the nitrogen oxide outlet X outlet Average value of static pressure at outlet P An outlet And an average value T of the outlet temperature An outlet Then correcting the theoretical ammonia spraying amount obtained by the calculation in the first step to obtain the ammonia spraying amount w 2 ；
And a third step of: when NO X outlet Less than 50mg/m 3 Relative standard deviation D An outlet When the ammonia injection optimization adjustment is less than 10 percent, ending; when D is An outlet When the concentration of the nitrogen oxides is more than 10%, the position with larger deviation of the concentration of the nitrogen oxides is adjustedAmmonia spraying grille for NO X outlet Less than 50mg/m 3 And D is An outlet Less than 10%;
fourth step: measuring the concentration, temperature and pressure of nitrogen oxides at the inlet and the outlet of each catalyst installation module by using four sets of measuring pipe networks, respectively calculating the denitration efficiency of each module, recording data, analyzing the running condition of the module, and providing a basis for replacing the catalyst;
fifth step: and opening a purging valve, and using compressed air to self-clean the measurement pipe network.
6. The adjustment method of the SCR denitration automatic ammonia injection optimization adjustment system according to claim 5, wherein: theoretical ammonia injection amount w in the first step 1 The calculation formula of (2) is as follows:
wherein: theoretical ammonia injection amount w 1 Is in kg/h; η is denitration efficiency,%; q (Q) 0 In the form of standard state, dry basis and the smoke quantity under the actual oxygen content, m 3 /h；NO X inlet Is the average value of the concentration of nitrogen oxides at the denitration inlet;
the calculation formula of eta is as follows:
wherein: NO (NO) X outlet For the average value of the concentration of the nitrogen oxide at the denitration outlet, 50mg/m is taken 3 。
7. The adjustment method of the SCR denitration automatic ammonia injection optimization adjustment system according to claim 6, wherein:
wherein: q (Q) w For denitration inlet standard state, wet basis and smoke quantity under actual oxygen content, m 3 /h；T An inlet Is the average temperature of a denitration inlet, and is at the temperature of DEG C; p (P) An inlet The average static pressure Pa of a denitration inlet; b (B) a Atmospheric pressure, pa; θ is the moisture content of the flue gas,%.
8. The adjustment method of the SCR denitration automatic ammonia injection optimization adjustment system according to claim 7, wherein:
Q w ＝3600×S×V i
wherein: s is the measured sectional area, m 2 ；V i To measure the speed of the i-point, m/s.
9. The adjustment method of the SCR denitration automatic ammonia injection optimization adjustment system according to claim 8, wherein:
wherein: k is the backrest tube coefficient, and 0.84 is taken; ΔP An inlet To measure the dynamic pressure of point i, pa; ρ is standard state, wet-base smoke density, kg/m 3 The method comprises the steps of carrying out a first treatment on the surface of the The calculation formula of ρ is:
wherein: o (O) 2 inlet The dry oxygen volume percent in the flue gas is,%;
CO 2 inlet The volume percent of the dry carbon dioxide gas in the flue gas is percent;
SO 2 inlet The volume percent of dry sulfur dioxide gas in the flue gas is percent;
1.4286kg of oxygen density of standard state and wet base/m 3 ；
1.9643kg/m of standard state and wet carbon dioxide density 3 ；
2.8580kg/m of standard state and wet-base sulfur dioxide density 3 ；
0.8036kg/m of the standard state and wet base steam density 3 ；/>1.2507kg/m of standard state and wet nitrogen density 3 。
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| CN111389219B (en) * | 2020-03-27 | 2021-11-02 | 浙江浙能技术研究院有限公司 | Ammonia injection control method for start-stop stage of coal-fired boiler |
| CN111467958B (en) * | 2020-04-16 | 2021-11-23 | 华北电力科学研究院有限责任公司 | Method for determining ammonia injection flow of each branch pipe of ammonia injection grid of denitration device |
| CN111610291A (en) * | 2020-04-24 | 2020-09-01 | 国网河北省电力有限公司电力科学研究院 | Power station boiler SCR (Selective catalytic reduction) inlet and outlet section NOxMeasuring system for concentration field |
| CN112379035B (en) * | 2020-10-28 | 2022-11-01 | 国网山东省电力公司电力科学研究院 | System and method for evaluating performance of SCR (selective catalytic reduction) denitration device catalyst on line |
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