Rapid measurement system for concentration of nitrogen oxide in flue gas of coal-fired power plant

Abstract

The utility model discloses a coal-fired power plant flue gas nitrogen oxide concentration rapid measuring system, which comprises a power plant coal-fired system, a power plant flue gas nitrogen oxide concentration rapid measuring system, a power plant flue gas nitrogen oxide concentration rapid measuring system and a power plant flue gas nitrogen oxide concentration rapid measuring system, the measuring mechanism is installed at the first corner of the flue and comprises an identification assembly and a controller electrically connected with the identification assembly. According to the system for rapidly measuring the concentration of the nitric oxide in the flue gas of the coal-fired power plant, by setting the mounting position of the measuring mechanism, the timeliness of detection can be improved, the updating performance of the flue gas at the position is good, the measured data representativeness is good, and the system is mounted at the first corner of a flue and is a certain distance away from denitration; therefore, the measured data is earlier than the concentration of nitrogen oxides in the actual denitration flue gas.

Description

Technical Field

[0001] The utility model relates to the technical field of flue gas treatment, in particular to a rapid measurement system for the concentration of nitrogen oxides in the flue gas of a coal-fired power plant. Background Technique

[0002] Nitrogen oxides (NOx) are one of the main pollutants in the flue gas of coal-fired power plants and must be removed. The domestic coal-fired power plant nitrogen oxide reduction technology mainly adopts selective catalytic reduction (SCR) denitration method. Its principle is to spray ammonia into the flue gas duct, and react chemically with the nitrogen oxides (mainly nitric oxide, NO) in the flue gas under the action of a catalyst to generate harmless nitrogen and water vapor. During the denitration (removal of nitrogen oxides) operation, it is necessary to accurately calculate the amount of ammonia required. When the sprayed ammonia is insufficient, the denitration is incomplete, which will lead to the exceeding of the flue gas pollutant emissions; when the sprayed ammonia is excessive, part of the ammonia cannot react (this unreacted ammonia is called ammonia slip), and it will enter the downstream equipment along with the flue gas. When the ammonia slip is large, a series of reactions will occur in the downstream equipment such as air preheaters and low-temperature economizers, blocking the flue gas circulation pipeline, thereby reducing the heat exchange capacity of the equipment, increasing the energy consumption of the induced draft fan, increasing the operation cost of the unit, and even seriously affecting the load capacity of the unit and causing the unit to trip unexpectedly.

[0003] Therefore, accurate calculation of the ammonia demand is very important for the economic and safe operation of the denitration system. Under the background that coal-fired generating units generally adopt flexible peak shaving, the load of the unit fluctuates rapidly with the load demand of the power grid, and the concentration of NOx in the flue gas is also changing all the time. Therefore, the ammonia demand is also a quantity that changes with time. Timely and accurate measurement of the nitrogen oxide concentration is a necessary condition for the economic and safe operation of the denitration system.

[0004] The measurement of nitrogen oxide concentration mainly adopts the infrared differential method. By measuring the loss of a specific spectrum in the optical path, quantitative measurement of the concentration is achieved. However, the flue gas duct of a coal-fired power plant is usually about 10 meters in size, and infrared light cannot penetrate it. Therefore, the existing measurement of nitrogen oxide concentration mainly adopts extraction analysis: extracting a part of the flue gas from a specific position in the flue gas duct, filtering and tracing heat, and then sending it to the analysis room. This process often takes more than 5 minutes. That is to say, the actual NOx concentration measured each time is the flue gas 5 minutes ago. In addition, due to the sampling position of the nitrogen oxide concentration measurement being a single point, it cannot fully represent the NOx concentration of the entire flue gas duct cross-section, and the representativeness is poor. The existing nitrogen oxide concentration measurement has problems such as large delay and poor representativeness, which have become the key pain points in the denitration ammonia injection control and need to be solved urgently. Content of the Utility Model

[0005] (1) Technical Problems to be Solved

[0006] In view of the deficiencies of the prior art, the present utility model provides a rapid measurement system for the concentration of nitrogen oxides in the flue gas of a coal-fired power plant, which solves the problems of large delay and poor representativeness in the existing measurement of nitrogen oxide concentration.

[0007] (II) Technical Solution

[0008] To achieve the above object, the present utility model provides the following technical solution: A rapid measurement system for the concentration of nitrogen oxides in the flue gas of a coal-fired power plant, including,

[0009] A power station coal combustion system, which includes a boiler and a flue disposed at the smoke outlet of the boiler;

[0010] A measuring mechanism, installed at the first corner of the flue, which includes an identification component and a controller electrically connected to the identification component.

[0011] Through the above technical solution, by using the measuring mechanism, the concentration of nitrogen oxides inside the flue can be measured in a timely manner.

[0012] Preferably, the identification component includes an optical path cavity, a light source emitter and a light source receiver installed at both ends of the optical path cavity, and air permeable holes opened on the surface of the optical path cavity;

[0013] The optical path cavity, the light source emitter and the light source receiver are fixedly connected, and the light source emitter and the light source receiver are respectively fixedly installed on the outer wall of the flue.

[0014] Through the above technical solution, the fixedly connected structure can ensure the relative stability of the light source emitter and the light source receiver, thereby improving the measurement accuracy.

[0015] Preferably, the measuring mechanism is installed at the first corner of the flue, and the angle of the corner is greater than ° and less than °.

[0016] Through the above technical solution, the measurement accuracy of the measuring mechanism can be further improved.

[0017] Preferably, a plurality of groups of the air permeable holes are provided, and the cross section of the air permeable holes is trapezoidal.

[0018] Through the above technical solution, the flue gas can pass through the air permeable holes and enter the inside of the optical path cavity.

[0019] Preferably, the light source emitter and the light source receiver are respectively electrically connected to the controller, the light source emitter transmits a light intensity signal to the controller, and the light source receiver transmits a light intensity signal to the controller.

[0020] Through the above technical solution, the controller respectively obtains the light intensity signals of the light source emitter and the light source receiver.

[0021] (III) Beneficial Effects

[0022] The utility model provides a rapid measurement system for the concentration of nitrogen oxides in the flue gas of a coal-fired power plant, which has the following beneficial effects:

[0023] For the rapid measurement system for the concentration of nitrogen oxides in the flue gas of a coal-fired power plant, by setting the installation position of the measurement mechanism, the timeliness of detection can be increased, and the flue gas at this position has good renewal performance, and the measured data has good representativeness. It is installed at the first corner of the flue, and there is still a certain distance from the denitration. Therefore, the measured data is earlier than the concentration of nitrogen oxides in the actual denitrated flue gas;

[0024] The optical path cavity, the light source emitter and the light source receiver are connected as a whole, which avoids the situation that the source emitter and the light source receiver cannot be aligned due to factors such as thermal displacement and vibration of the flue wall surface, and improves the stability of the measuring device. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a schematic diagram of the overall structure of the utility model.

[0026] Figure 2 It is a schematic diagram of the structure of the measurement mechanism of the utility model. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0027] Next, the technical solutions in the embodiments of the present utility model will be clearly and completely described in conjunction with the drawings in the embodiments of the present utility model. Obviously, the described embodiments are only a part of the embodiments of the present utility model, rather than all the embodiments. Based on the embodiments in the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present utility model.

[0028] As Figure 1-2 shown, the present utility model provides a technical solution: a rapid measurement system for the concentration of nitrogen oxides in the flue gas of a coal-fired power plant, including,

[0029] a power station coal combustion system 100, which includes a boiler 101 and a flue 102 arranged at the smoke outlet position of the boiler 101;

[0030] a measurement mechanism 200, installed at the first corner of the flue 102, which includes an identification component 201 and a controller 202 electrically connected to the identification component 201;

[0031] By using the measurement mechanism 200, the concentration of nitrogen oxides inside the flue 102 can be measured in a timely manner.

[0032] As Figure 2, the recognition component 201 includes an optical path cavity 201a, a light source emitter 201b and a light source receiver 201c installed at both ends of the optical path cavity 201a, and a ventilation hole 201d opened on the surface of the optical path cavity 201a;

[0033] The optical path cavity 201a, the light source emitter 201b and the light source receiver 201c are fixedly connected, and the light source emitter 201b and the light source receiver 201c are respectively fixedly installed on the outer wall of the flue 102;

[0034] The fixedly connected structure can ensure the relative stability of the light source emitter 201b and the light source receiver 201c, thereby improving the measurement accuracy.

[0035] Such as Figure 2 , the measuring mechanism 200 is installed at the first corner of the flue 102, and the angle of the corner is greater than 75° and less than 105°;

[0036] It can further improve the measurement accuracy of the measuring mechanism 200.

[0037] Such as Figure 2 , a plurality of groups of ventilation holes 201d are provided, and the cross section of the ventilation hole 201d is trapezoidal;

[0038] The flue gas can pass through the ventilation hole 201d and enter the inside of the optical path cavity 201a.

[0039] Such as Figure 2 , the light source emitter 201b and the light source receiver 201c are respectively electrically connected to the controller 202, the light source emitter 201b transmits an optical intensity signal I1 to the controller 202, and the light source receiver 201c transmits an optical intensity signal I2 to the controller 202;

[0040] The controller 202 respectively obtains the optical intensity signals of the light source emitter 201b and the light source receiver 201c.

[0041] During use, first, the flue gas will enter the inside of the flue 102 from the boiler 101, and then pass through the ventilation hole 201d and enter the inside of the optical path cavity 201a. The light source emitter 201b and the light source receiver 201c are oppositely arranged, so the flue gas will be captured. Finally, the controller (202) judges the situation of the flue gas by identifying the difference in the transmitted optical intensity signals, and the judged situation will be wirelessly transmitted to each display terminal for the staff to observe. This is the use process of the rapid measurement system for the concentration of nitrogen oxides in the flue gas of this coal-fired power plant. At the same time, the content not described in detail in this specification belongs to the prior art well-known to those skilled in the art.

[0042] It should be noted that in this text, relational terms such as "first" and "second" are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "comprising", "including" or any other variant thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device comprising a series of elements not only includes those elements, but also includes other elements not expressly listed, or further includes elements inherent to such process, method, article or device. Without further limitation, an element defined by the statement "comprising an..." does not exclude the presence of additional identical elements in the process, method, article or device comprising the element.

[0043] Although embodiments of the present invention have been shown and described, those of ordinary skill in the art can understand that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of the present invention. The scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A rapid measurement system for nitrogen oxide concentration in flue gas of a coal-fired power plant, characterized by: include, A power plant coal-fired system (100), comprising a boiler (101) and a flue (102) arranged at a smoke outlet of the boiler (101); The measuring mechanism (200) is installed at the first corner of the flue (102), and comprises an identification component (201) and a controller (202) electrically connected to the identification component (201).

2. A rapid measurement system for flue gas nitrogen oxide concentration in a coal-fired power plant according to claim 1, characterized in that: The identification component (201) comprises an optical path cavity (201a), a light source transmitter (201b) and a light source receiver (201c) installed at two ends of the optical path cavity (201a), and an air hole (201d) provided on the surface of the optical path cavity (201a); The optical path cavity (201a), the light source transmitter (201b) and the light source receiver (201c) are fixedly connected, and the light source transmitter (201b) and the light source receiver (201c) are respectively fixedly mounted on the outer wall of the flue (102).

3. A rapid measurement system for flue gas nitrogen oxide concentration in a coal-fired power plant according to claim 2, characterized in that: The measuring mechanism (200) is installed at the first corner of the flue (102), and the angle of the corner is greater than 75° and less than 105°.

4. A rapid measurement system for flue gas nitrogen oxide concentration in a coal-fired power plant according to claim 3, characterized in that: The ventilation holes (201d) are arranged in a plurality of groups, and the cross section of the ventilation holes (201d) is trapezoidal.

5. A rapid measurement system for flue gas nitrogen oxide concentration in a coal-fired power plant according to claim 4, characterized in that: The light source transmitter (201b) and the light source receiver (201c) are electrically connected to the controller (202) respectively; the light source transmitter (201b) transmits a light intensity signal I1 to the controller (202), and the light source receiver (201c) transmits a light intensity signal I2 to the controller (202).

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