Denitration ammonia injection self-adaptive control device, system and control method

Abstract

The invention provides a denitration ammonia spraying self-adaptive control device, system and control method, and belongs to the technical field of denitration equipment. The denitration ammonia spraying self-adaptive control device comprises a reaction assembly and an ammonia spraying assembly. The reaction assembly comprises a reactor, and a gas outlet pipe is arranged at the top of the reactor; the ammonia spraying assembly comprises an ammonia spraying driving part, the liquid outlet end of the ammonia spraying driving part is communicated with an ammonia spraying part, the ammonia spraying part extends to be located in the reactor, the reactor is provided with a return pipe, and the return pipe is communicated with the ammonia spraying driving part. The requirement for different ammonia spraying amounts of all areas of the flue section can be met, the ammonia / nitrogen molar ratio is evenly distributed, NOx can completely react and be reduced and absorbed, and the situation that the emission concentration exceeds the standard is avoided.

Description

Technical Field

[0001] The present application relates to the field of denitration equipment, and more specifically, to a denitration ammonia injection adaptive control device, system and control method. Background Art

[0002] In denitration transformation, some positive measures have also been taken. First, the flow field is further optimized and transformed to ensure the uniformity of the flue gas flow velocity and NOx concentration distribution at the SCR inlet section. However, due to the influence of site space limitations, the effect is not high. Therefore, the number of NOx concentration measurement probes at the SCR system inlet is increased, from one sampling probe to three sampling probes, and multi-point flue gas mixed sampling is carried out. However, these methods still make the NOx concentration measurement data at the SCR system inlet not representative enough to measure the actual concentration of the entire flue duct section. At the same time, the ammonia injection control system still uses one regulating valve for regulation, which cannot meet the requirements of different ammonia injection amounts in each area of the flue duct section, resulting in uneven ammonia / nitrogen molar ratio. If it is too large, ammonia cannot fully participate in the reaction, and ammonia escape at the reactor outlet increases; if it is too small, the ammonia injection amount is insufficient, and NOx cannot all react and be reduced and absorbed, resulting in excessive emission concentration. Summary of the Invention

[0003] To make up for the above deficiencies, the present application provides a denitration ammonia injection adaptive control device, system and control method, aiming to improve the problem that the ammonia injection control system still uses one regulating valve for regulation and cannot meet the requirements of different ammonia injection amounts in each area of the flue duct section.

[0004] In a first aspect, an embodiment of the present application provides a denitration ammonia injection adaptive control device, including a reaction component and an ammonia injection component.

[0005] The reaction component includes a reactor, and an outlet pipe is arranged at the top of the reactor;

[0006] The ammonia injection component includes an ammonia injection driving member, the liquid outlet end of the ammonia injection driving member is communicated with an ammonia spraying member, and the ammonia spraying member extends into the reactor. A reflux pipe is arranged on the reactor and is communicated with the ammonia injection driving member.

[0007] In a specific implementation, the ammonia spraying member includes a liquid outlet main pipe, one end of the liquid outlet main pipe is communicated with the ammonia injection driving member, the other end of the liquid outlet main pipe extends into the reactor and is communicated with a spraying disc, and the spraying disc is installed inside the reactor.

[0008] In a specific implementation, the liquid outlet main pipe is communicated with a first liquid outlet branch pipe and a second liquid outlet branch pipe inside the reactor, and the first liquid outlet branch pipe and the second liquid outlet branch pipe are respectively communicated with the spraying disc.

[0009] In a specific embodiment, the spray tray is arranged in layers.

[0010] In a specific embodiment, the reaction assembly further includes a bottom plate, on which an installation frame is provided, and the reactor is installed on the installation frame.

[0011] In a specific embodiment, a support frame body is further installed on the bottom plate, and the ammonia injection driving member is installed on the support frame body.

[0012] In a second aspect, an embodiment of the present application provides a denitration ammonia injection adaptive control system, including an ammonia injection amount feedforward signal generation unit, an adaptive PID controller, and an SCR denitration system.

[0013] The ammonia injection amount feedforward signal generation unit is connected to the operating data sensor of the coal-fired power generation unit combustion system. Based on the operating data collected by the operating data sensor of the coal-fired power generation unit combustion system, an inlet nitrogen oxide concentration model is established; and using this inlet nitrogen oxide concentration model and the currently collected operating data, a predicted value of the inlet nitrogen oxide concentration is obtained, and then an ammonia injection amount feedforward signal under the current operating condition is calculated according to the predicted value of the inlet nitrogen oxide concentration; the adaptive PID controller is connected to the outlet nitrogen oxide concentration measuring instrument, and is used to obtain an ammonia injection amount feedback control signal according to the deviation between the measured value of the outlet nitrogen oxide concentration and the set value of the outlet nitrogen oxide concentration of the coal-fired power generation unit combustion system; wherein, the adaptive PID controller adjusts the PID parameters under the current condition by using an adaptive PID control algorithm; the SCR denitration system is respectively connected to the ammonia injection amount feedforward signal generation unit and the adaptive PID controller to receive the ammonia injection amount feedforward signal and the ammonia injection amount feedback control signal, and is used to control the ammonia injection amount of the SCR denitration reactor according to the ammonia injection amount feedforward signal and the ammonia injection amount feedback control signal.

[0014] In a specific embodiment, the adaptive PID controller includes a nitrogen oxide concentration controller, a differential operator, and an ammonia injection branch partition control valve. Among them, the nitrogen oxide concentration controller can control the concentration of nitrogen oxides, the differential operator can perform optimization operations, provide accurate instructions for differential ammonia injection adjustment of the ammonia injection branch valves, perform measurement, comparison, and ammonia injection control in a timely manner, and achieve precise control of the ammonia / nitrogen molar ratio in different regions at the inlet of SCR denitration. The ammonia injection branch partition control valve can automatically control the ammonia water in each region.

[0015] In a third aspect, an embodiment of the present application further provides a denitration ammonia injection adaptive control method, including the following steps:

[0016] Step 1: Based on the operation data of the combustion system of a coal-fired thermal power unit, establish an inlet nitrogen oxide concentration model; then, using the inlet nitrogen oxide concentration model and the currently collected operation data, obtain the predicted value of the inlet nitrogen oxide concentration.

[0017] Step 2: Calculate the ammonia injection amount under the current operating condition as a feedforward signal according to the predicted value of the inlet nitrogen oxide concentration, and send the ammonia injection amount feedforward signal to the ammonia injection assembly.

[0018] Step 3: Measure the measured value of the outlet nitrogen oxide concentration of the combustion system of the coal-fired thermal power unit, input the deviation between the measured value and the set value of the outlet nitrogen oxide concentration into an adaptive PID controller, and the adaptive PID controller obtains a feedback control signal for the ammonia injection amount based on the deviation and sends it to the SCR denitration system; among them, the adaptive PID controller adjusts the PID parameters under the current working condition by using an adaptive PID control algorithm.

[0019] Step 4: The ammonia injection assembly controls the ammonia injection amount of the ammonia injection assembly according to the ammonia injection amount feedforward signal and the ammonia injection amount feedback control signal.

[0020] In a specific implementation, the operation data is divided by the principal component analysis algorithm to determine the parameters closely related to the inlet nitrogen oxide; then, the determined parameters closely related to the inlet nitrogen oxide are used as training data, and a deep learning algorithm or a least squares support vector machine algorithm is used to establish an inlet nitrogen oxide concentration model.

[0021] Beneficial effects: The present application provides a denitration ammonia injection adaptive control device, system and control method. Through the setting of the ammonia injection driving part and the ammonia spraying part, it can meet the requirements of different ammonia injection amounts in each area of the flue gas cross-section, make the ammonia / nitrogen molar ratio distribution uniform, and all NOx can be reacted and reduced and absorbed, without causing the emission concentration to exceed the standard. Description of the Drawings

[0022] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following will briefly introduce the drawings required in the embodiments. It should be understood that the following drawings only show some embodiments of the present application, and therefore should not be regarded as limiting the scope. For those of ordinary skill in the art, other related drawings can be obtained based on these drawings without creative efforts.

[0023] Figure 1 It is a schematic structural diagram of a denitration ammonia injection adaptive control device, system and control method provided by an embodiment of the present application;

[0024] Figure 2 It is a schematic structural diagram of a denitration ammonia injection adaptive control device provided by an embodiment of the present application;

[0025] Figure 3 Schematic diagram of the spray tray structure provided by the embodiment of the present application:

[0026] Figure 4 Block diagram of the denitration ammonia injection adaptive control system provided by the embodiment of the present application.

[0027] In the figure: 10 - reaction component; 110 - reactor; 120 - outlet pipe; 130 - mounting bracket; 140 - bottom plate; 20 - ammonia injection component; 210 - ammonia injection driving part; 220 - main liquid outlet pipe; 221 - first liquid outlet branch pipe; 222 - second liquid outlet branch pipe; 230 - spray tray; 240 - return pipe; 250 - support frame. Specific embodiments

[0028] Next, the technical solutions in the embodiments of the present application will be described with reference to the accompanying drawings in the embodiments of the present application.

[0029] Please refer to Figures 1-4 , the present application provides a denitration ammonia injection adaptive control device, including a reaction component 10 and an ammonia injection component 20.

[0030] Please refer to Figure 1 , Figure 2 and Figure 3 , the reaction component 10 includes a reactor 110, and an outlet pipe 120 is provided at the top of the reactor 110; the reaction component 10 further includes a bottom plate 140, a mounting bracket 130 is provided on the bottom plate 140, and the reactor 110 is installed on the mounting bracket 130.

[0031] Please refer to Figure 1 , Figure 2 and Figure 3 , the ammonia injection component 20 includes an ammonia injection driving part 210, the liquid outlet end of the ammonia injection driving part 210 is communicated with an ammonia spray part, and the ammonia spray part extends into the reactor 110, a return pipe 240 is provided on the reactor 110, and the return pipe 240 is communicated with the ammonia injection driving part 210

[0032] In this embodiment, the ammonia spray part includes a main liquid outlet pipe 220, one end of the main liquid outlet pipe 220 is communicated with the ammonia injection driving part 210, the other end of the main liquid outlet pipe 220 extends into the reactor 110 and is communicated with a spray tray 230, and the spray tray 230 is installed inside the reactor 110. The main liquid outlet pipe 220 is communicated with a first liquid outlet branch pipe 221 and a second liquid outlet branch pipe 222 inside the reactor 110, and the first liquid outlet branch pipe 221 and the second liquid outlet branch pipe 222 are respectively communicated with the spray tray 230. The spray tray 230 is arranged in layers.

[0033] When specifically setting, a support frame 250 is further installed on the bottom plate 140, and the ammonia injection driving part 210 is installed on the support frame 250.

[0034] Please refer to Figure 4 , the embodiment of the present application provides a denitration ammonia injection adaptive control system, including an ammonia injection amount feedforward signal generation unit, an adaptive PID controller, and an SCR denitration system.

[0035] The ammonia injection amount feedforward signal generation unit is connected to the operating data sensor of the combustion system of the coal-fired power generation unit. Based on the operating data collected by the operating data sensor of the combustion system of the coal-fired power generation unit, an inlet nitrogen oxide concentration model is established; and by using this inlet nitrogen oxide concentration model and the currently collected operating data, the predicted value of the inlet nitrogen oxide concentration is obtained, and then the ammonia injection amount feedforward signal under the current operating condition is calculated according to the predicted value of the inlet nitrogen oxide concentration; The adaptive PID controller is connected to the outlet nitrogen oxide concentration measuring instrument and is used to obtain the ammonia injection amount feedback control signal according to the deviation between the measured value of the outlet nitrogen oxide concentration and the set value of the outlet nitrogen oxide concentration of the combustion system of the coal-fired power generation unit; among them, the adaptive PID controller uses the adaptive PID control algorithm to adjust the PID parameters under the current condition; The SCR denitration system is respectively connected to the ammonia injection amount feedforward signal generation unit and the adaptive PID controller to receive the ammonia injection amount feedforward signal and the ammonia injection amount feedback control signal, and is used to control the ammonia injection amount of the SCR denitration reactor 110 according to the ammonia injection amount feedforward signal and the ammonia injection amount feedback control signal. The adaptive PID controller includes a nitrogen oxide concentration controller, a differential operator, and an ammonia injection branch partition control valve. Among them, the nitrogen oxide concentration controller can control the concentration of nitrogen oxides, and the differential operator can perform optimization operations to provide accurate instructions for the differential ammonia injection adjustment of the ammonia injection branch valves, and perform measurement, comparison, and ammonia injection control in a timely manner to achieve precise control of the ammonia / nitrogen molar ratio in different regions at the SCR denitration inlet. The ammonia injection branch partition control valve can automatically control the ammonia water in each region. The operating data is divided by the principal component analysis algorithm to determine the parameters closely related to the inlet nitrogen oxides; then the determined parameters closely related to the inlet nitrogen oxides are used as training data, and a deep learning algorithm or a least squares support vector machine algorithm is used to establish an inlet nitrogen oxide concentration model; The operating data includes unit load, primary air volume, secondary air volume, total coal volume, and the number of operating coal mills. The adaptive PID controller establishes an SCR ammonia injection system model based on the inlet nitrogen oxide concentration and the outlet nitrogen oxide concentration; then the genetic algorithm or the PSO optimization algorithm is used to optimize the parameters of the SCR ammonia injection system model to obtain the optimal PID parameters of the adaptive PID controller. The adaptive PID controller establishes an SCR denitration input-output system model based on the characteristic parameters of different operating conditions of the combustion system of the coal-fired power generation unit during the initial commissioning, and determines the PID parameters of the adaptive PID controller through this SCR denitration input-output system model; during operation, based on the real-time collected operating data of the combustion system of the coal-fired power generation unit, the SCR denitration input-output system model is corrected, and then the optimal PID parameters under the current condition are obtained based on the corrected SCR denitration input-output system model

[0036] Please refer to Figures 1-4, another embodiment of the present application further provides a denitration ammonia injection adaptive control method, including the following steps:

[0037] Step 1: Based on the operation data of the combustion system of a coal-fired thermal power unit, establish an inlet nitrogen oxide concentration model; then use the inlet nitrogen oxide concentration model and the currently collected operation data to obtain the predicted value of the inlet nitrogen oxide concentration; Step 2: Calculate the ammonia injection amount under the current operating condition as a feedforward signal according to the predicted value of the inlet nitrogen oxide concentration, and send the ammonia injection amount feedforward signal to the ammonia injection assembly 20; Step 3: Measure the measured value of the outlet nitrogen oxide concentration of the combustion system of the coal-fired thermal power unit, and input the deviation between the measured value and the set value of the outlet nitrogen oxide concentration into an adaptive PID controller. The adaptive PID controller obtains an ammonia injection amount feedback control signal based on the deviation and sends it to the SCR denitration system; among them, the adaptive PID controller uses an adaptive PID control algorithm to adjust the PID parameters under the current condition; Step 4: The ammonia injection assembly 20 controls the ammonia injection amount of the ammonia injection assembly 20 according to the ammonia injection amount feedforward signal and the ammonia injection amount feedback control signal. Divide the operation data through the principal component analysis algorithm to determine the parameters closely related to the inlet nitrogen oxide; then use the determined parameters closely related to the inlet nitrogen oxide as training data, and use a deep learning algorithm or a least squares support vector machine algorithm to establish an inlet nitrogen oxide concentration model. The operation data includes unit load, primary air volume, secondary air volume, total coal volume, and the number of operating coal mills. The method for obtaining the ammonia injection amount feedforward signal is: multiply the predicted value by the flue gas volume, and then multiply by the ammonia-nitrogen molar ratio to calculate the ammonia gas demand, which is used as the ammonia injection amount feedforward signal of the SCR denitration system. The adaptive PID controller establishes an SCR ammonia injection system model based on the inlet nitrogen oxide concentration and the outlet nitrogen oxide concentration; then uses a genetic algorithm or a PSO optimization algorithm to optimize the parameters of the SCR ammonia injection system model to obtain the optimal PID parameters of the adaptive PID controller. The method for the adaptive PID controller to use the adaptive PID control algorithm to adjust the PID parameters under the current condition is: during the initial commissioning, obtain the characteristic parameters of the combustion system of the coal-fired thermal power unit under different conditions according to on-site tests, establish an SCR denitration input-output system model, and determine the PID parameters of the adaptive PID controller through the SCR denitration input-output system model; during operation, collect the operation data of the combustion system of the coal-fired thermal power unit in real time, and correct the SCR denitration input-output system model, and then obtain the optimal PID parameters under the current condition based on the corrected SCR denitration input-output system model.

[0038] The denitration ammonia injection adaptive control device, system and control method: Step 1: Based on the operation data of the combustion system of a coal-fired thermal power unit, establish an inlet nitrogen oxide concentration model; then use the inlet nitrogen oxide concentration model and the currently collected operation data to obtain the predicted value of the inlet nitrogen oxide concentration; Step 2: Calculate the ammonia injection amount under the current operating condition as a feedforward signal according to the predicted value of the inlet nitrogen oxide concentration, and send the ammonia injection amount feedforward signal to the ammonia injection component 20; Step 3: Measure the measured value of the outlet nitrogen oxide concentration of the combustion system of the coal-fired thermal power unit, make a deviation between the measured value and the set value of the outlet nitrogen oxide concentration, and input it into the adaptive PID controller. The adaptive PID controller obtains the ammonia injection amount feedback control signal based on the deviation and sends it to the SCR denitration system; among them, the adaptive PID controller uses the adaptive PID control algorithm to adjust the PID parameters under the current working condition; Step 4: The ammonia injection component 20 controls the ammonia injection amount of the ammonia injection component 20 according to the ammonia injection amount feedforward signal and the ammonia injection amount feedback control signal. Through the setting of the ammonia injection driving part 210 and the ammonia spraying part, it is possible to meet the requirements of different ammonia injection amounts in each area of the flue gas cross-section, make the ammonia / nitrogen molar ratio distribution uniform, and enable all NOx to react and be reduced and absorbed, without causing the emission concentration to exceed the standard.

[0039] The above are only the embodiments of the present application and are not used to limit the protection scope of the present application. For those skilled in the art, the present application can have various changes and modifications. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included within the protection scope of the present application. It should be noted that similar reference numerals and letters denote similar items in the following drawings. Therefore, once an item is defined in one drawing, it does not need to be further defined and explained in subsequent drawings.

Claims

1. A denitrification ammonia injection adaptive control device, characterized in that: include A reaction assembly (10) comprises a reactor (110), wherein a gas outlet pipe (120) is arranged at the top of the reactor (110); The ammonia spraying assembly (20) comprises an ammonia spraying driving component (210), wherein the liquid outlet end of the ammonia spraying driving component (210) is connected to an ammonia spraying component, and the ammonia spraying component extends and is located inside the reactor (110); a reflux pipe (240) is provided on the reactor (110), and the reflux pipe (240) is connected to the ammonia spraying driving component (210).

2. The denitration ammonia injection adaptive control device according to claim 1, characterized in that: The ammonia spray component comprises a liquid outlet main pipe (220), one end of the liquid outlet main pipe (220) is connected to the ammonia spray drive component (210), the other end of the liquid outlet main pipe (220) extends to the interior of the reactor (110) and is connected to a spray plate (230), and the spray plate (230) is installed inside the reactor (110).

3. A denitration ammonia injection adaptive control device according to claim 2, characterized in that: The liquid outlet main pipe (220) is located inside the reactor (110) and is connected to a first liquid outlet branch pipe (221) and a second liquid outlet branch pipe (222); the first liquid outlet branch pipe (221) and the second liquid outlet branch pipe (222) are respectively connected to the spray plate (230).

4. The denitration ammonia injection adaptive control device according to claim 2, characterized in that: The spray plates (230) are arranged in layers.

5. The denitration ammonia injection adaptive control device according to claim 1, characterized in that: The reaction assembly (10) further comprises a base plate (140), a mounting frame (130) is arranged on the base plate (140), and the reactor (110) is mounted on the mounting frame (130).

6. The denitration ammonia injection adaptive control device according to claim 5, characterized in that: A support frame (250) is also installed on the base plate (140), and the ammonia injection drive component (210) is installed on the support frame (250).

7. A denitrification ammonia injection adaptive control system, characterized in that: include An ammonia injection amount feedforward signal generating unit, an adaptive PID controller and an SCR denitration system; wherein the ammonia injection amount feedforward signal generating unit is connected to the coal-fired power unit combustion system operation data sensor, and establishes an inlet nitrogen oxide concentration model based on the operation data collected by the coal-fired power unit combustion system operation data sensor; and uses the inlet nitrogen oxide concentration model and the currently collected operation data to obtain a predicted value of the inlet nitrogen oxide concentration, and then calculates the ammonia injection amount feedforward signal under the current operation condition according to the inlet nitrogen oxide concentration predicted value; the adaptive PID controller is connected to the outlet nitrogen oxide concentration measuring instrument, and is used to obtain an ammonia injection amount feedback control signal according to the deviation between the measured value of the outlet nitrogen oxide concentration of the coal-fired power unit combustion system and the set value of the outlet nitrogen oxide concentration; wherein the adaptive PID controller uses an adaptive PID control algorithm to adjust the PID parameters under the current working condition; the SCR denitration system is respectively connected to the ammonia injection amount feedforward signal generating unit and the adaptive PID controller to receive the ammonia injection amount feedforward signal and the ammonia injection amount feedback control signal, and is used to control the ammonia injection amount of the SCR denitration reactor according to the ammonia injection amount feedforward signal and the ammonia injection amount feedback control signal.

8. The denitration ammonia injection adaptive control system according to claim 7, characterized in that: The adaptive PID controller includes a nitrogen oxide concentration controller, a differential operator and an ammonia injection branch zoning control valve. Among them, the nitrogen oxide concentration controller can control the concentration of nitrogen oxides, the differential operator can implement optimization operations, provide accurate instructions for the differentiated ammonia injection adjustment of the ammonia injection branch valve, and perform measurement, comparison and ammonia injection control in time to achieve precise control of the ammonia / nitrogen molar ratio in different areas of the SCR denitrification inlet. The ammonia injection branch zoning control valve can automatically control the ammonia water in each area.

9. A method for adaptive control of denitrification ammonia injection, characterized in that: The following steps are involved: Step 1: Based on the operating data of the combustion system of the coal-fired thermal power unit, an inlet nitrogen oxide concentration model is established; then, the inlet nitrogen oxide concentration model and the currently collected operating data are used to obtain the predicted value of the inlet nitrogen oxide concentration; Step 2: Calculate the ammonia injection amount under the current operating condition according to the predicted value of the inlet nitrogen oxide concentration as a feedforward signal, and send the ammonia injection amount feedforward signal to the ammonia injection component (20); Step 3: Measure the actual value of the outlet nitrogen oxide concentration of the combustion system of the coal-fired thermal power unit, make a deviation between the actual measured value and the outlet nitrogen oxide concentration set value, and input it into the adaptive PID controller. The adaptive PID controller obtains the ammonia injection amount feedback control signal based on the deviation and sends it to the SCR denitration system; wherein, the adaptive PID controller uses an adaptive PID control algorithm to adjust the PID parameters under the current working conditions; Step 4: the ammonia injection component (20) controls the ammonia injection amount of the ammonia injection component (20) according to its ammonia injection amount feedforward signal and ammonia injection amount feedback control signal.

10. A method for adaptively controlling denitration ammonia injection according to claim 9, characterized in that: The operating data is divided through the principal component analysis algorithm to determine the parameters closely related to the inlet nitrogen oxides; then the determined parameters closely related to the inlet nitrogen oxides are used as training data, and a deep learning algorithm or a least squares support vector machine algorithm is used to establish an inlet nitrogen oxide concentration model.

Images