A method and device for reducing ammonia injection in an SCR denitration system

Abstract

This invention discloses a method and apparatus for reducing ammonia injection in an SCR denitrification system, comprising: using a predictive model to reduce NO at the inlet of the SCR denitrification system. X The content of NO at the inlet was predicted. X Predicted content value; calculate NO at the inlet. X Real-time content value and NO at the inlet X The invention employs advanced prediction algorithms and sensor technology to achieve real-time monitoring and prediction of NOx content in flue gas. Based on this monitoring and prediction, the initial ammonia injection rate of the SCR denitrification system is set. The ammonia content at the outlet of the SCR denitrification system is obtained, and the ammonia slip rate is calculated using the initial injection rate and the outlet ammonia content. Simultaneously, it is determined whether the ammonia slip rate is lower than the set ammonia slip rate. If the ammonia slip rate is not lower than the set ammonia slip rate, the initial injection rate is adjusted according to the outlet ammonia content to obtain the final injection rate.

Description

Technical Field

[0001] This invention relates to the field of SCR denitrification system technology, and in particular to a method and apparatus for reducing ammonia injection in an SCR denitrification system. Background Technology

[0002] SCR (Selective Catalytic Reduction) denitrification systems are a commonly used air pollutant control technology to reduce nitrogen oxide (NOx) emissions generated during combustion. SCR systems convert NOx into harmless nitrogen and water vapor by injecting ammonia (NH3) or urea solution into the flue gas, using a catalyst. However, the ammonia injection method in SCR systems suffers from significant waste, such as ammonia escape. Therefore, improvements and optimizations to SCR denitrification systems are needed to reduce ammonia injection. Summary of the Invention

[0003] The technical problem to be solved by the present invention is that the electric heater of the denitrification system cannot be reset in a timely manner after a failure in the prior art.

[0004] To address the aforementioned technical problems, this invention provides a method for reducing ammonia injection in an SCR denitrification system, comprising:

[0005] The NO at the inlet of the SCR denitrification system was predicted using a predictive model. X The content of NO at the inlet was predicted. X Content prediction value;

[0006] Calculate NO at the entrance X Real-time content value and NO at the inlet X The average value of the predicted content is used to set the initial ammonia injection rate of the SCR denitrification system;

[0007] Obtain the ammonia content value at the outlet of the SCR denitrification system, and calculate the ammonia slip rate value of the SCR denitrification system based on the initial ammonia injection rate and the ammonia content value at the outlet. At the same time, determine whether the ammonia slip rate value is lower than the set ammonia slip rate value.

[0008] If the ammonia slip rate is not lower than the set ammonia slip rate, the initial ammonia injection amount is adjusted according to the ammonia content at the outlet to obtain the final ammonia injection amount.

[0009] Furthermore, the prediction model is used to analyze the NO at the inlet of the SCR denitrification system. X The content of NO at the inlet was predicted. X Prior to the predicted content values, including:

[0010] Obtain historical operating data of the generator set and construct a prediction model based on the historical operating data;

[0011] Obtain NO at the inlet of the SCR denitrification system X Real-time content value, based on the NO at the inlet. X The real-time content values ​​are used to correct the prediction model;

[0012] The NO at the inlet is predicted using the corrected prediction model. X Content prediction value.

[0013] Furthermore, the calculation of NO at the entrance... X Real-time content value and NO at the inlet X The average value of the predicted content, and the initial ammonia injection rate of the SCR denitrification system is set based on the average value, specifically including:

[0014] Calculate NO at the entrance X Real-time content value and NO at the inlet X The average of the predicted content values;

[0015] Calculate the difference between the average value and the set standard average value, and set the initial ammonia injection rate of the SCR denitrification system based on the magnitude of the difference.

[0016] Furthermore, the step of calculating the difference between the average value and the set standard average value, and setting the initial ammonia injection rate of the SCR denitrification system based on the magnitude of the difference, includes:

[0017] A standard average value G0 is preset, and a first preset difference g1, a second preset difference g2, a third preset difference g3 and a fourth preset difference g4 are set, where g1 < g2 < g3 < g4. A first preset ammonia injection amount A1, a second preset ammonia injection amount A2, a third preset ammonia injection amount A3 and a fourth preset ammonia injection amount A4 are also set, where A1 < A2 < A3 < A4.

[0018] The initial ammonia injection rate Ai of the SCR denitrification system is set according to the magnitude of the difference gi, where i = 1, 2, 3, 4;

[0019] When △G-G0≤g1, the first preset ammonia injection amount A1 is selected as the initial ammonia injection amount;

[0020] When g1 < ΔG - G0 ≤ g2, the second preset ammonia injection amount A2 is selected as the initial ammonia injection amount;

[0021] When g2 < ΔG - G0 ≤ g3, the third preset ammonia injection amount A3 is selected as the initial ammonia injection amount;

[0022] When g3 < △G - G0 ≤ g4, the fourth preset ammonia injection amount A4 is selected as the initial ammonia injection amount.

[0023] Further, the step of obtaining the ammonia content value at the outlet of the SCR denitrification system, and calculating the ammonia slip rate value of the SCR denitrification system based on the initial ammonia injection rate and the ammonia content value at the outlet, while determining whether the ammonia slip rate value is lower than the set ammonia slip rate value, includes:

[0024] Obtain the ammonia content at the outlet of the SCR denitrification system, and calculate the ammonia slip rate of the SCR denitrification system based on the initial ammonia injection rate and the ammonia content at the outlet.

[0025] Determine whether the ammonia slip rate value is lower than the set ammonia slip rate value:

[0026] If the ammonia slip rate is lower than the set ammonia slip rate, then there is no need to adjust the initial ammonia injection amount;

[0027] If the ammonia slip rate is not lower than the set ammonia slip rate, the initial ammonia injection amount needs to be adjusted.

[0028] Furthermore, if the ammonia slip rate value is not lower than the set ammonia slip rate value, then the initial ammonia injection amount is adjusted according to the ammonia content value at the outlet to obtain the final ammonia injection amount, including:

[0029] If the ammonia slip rate value is not lower than the set ammonia slip rate value, then obtain the ammonia content value ΔT at the outlet of the SCR denitrification system;

[0030] Set a first preset ammonia content value T1, a second preset ammonia content value T2, a third preset ammonia content value T3, and a fourth preset ammonia content value T4, where T1 < T2 < T3 < T4.

[0031] Set a first preset adjustment coefficient x1, a second preset adjustment coefficient x2, a third preset adjustment coefficient x3 and a fourth preset adjustment coefficient x4, and 1 < x1 < x2 < x3 < x4 < 1.5;

[0032] Based on the relationship between the obtained ammonia content value ΔT at the outlet and each preset ammonia content value Ti, a preset adjustment coefficient is selected to adjust the working conditions in the preset working condition matrix Ai.

[0033] When T1 < △T ≤ T2, the first preset adjustment coefficient x1 is selected to adjust the first preset ammonia injection quantity Ai, and the adjusted quantity is Ai * x1.

[0034] When T2 < △T ≤ T3, the second preset adjustment coefficient x2 is selected to adjust the second preset ammonia injection quantity Ai, and the adjusted quantity is Ai * x2.

[0035] When T3 < △T ≤ T4, the third preset adjustment coefficient x3 is selected to adjust the third preset ammonia injection quantity Ai, and the adjusted quantity is Ai * x3.

[0036] When T4 < △T, the fourth preset adjustment coefficient x4 is selected to adjust the fourth preset ammonia injection quantity Ai, and the adjusted quantity is Ai * x4.

[0037] Furthermore, the ammonia content at the outlet of the SCR denitrification system is the average ammonia content at the outlet of each flue of the SCR denitrification system.

[0038] The present invention also provides a device for reducing ammonia injection in an SCR denitrification system, comprising:

[0039] The prediction module is used to predict the NO at the inlet of the SCR denitrification system using a prediction model. X The content of NO at the inlet was predicted. X Content prediction value;

[0040] The setting module is used to calculate the NO at the entrance. X Real-time content value and NO at the inlet X The average value of the predicted content is used to set the initial ammonia injection rate of the SCR denitrification system;

[0041] The judgment module is used to obtain the ammonia content value at the outlet of the SCR denitrification system, calculate the ammonia slip rate value of the SCR denitrification system based on the initial ammonia injection rate and the ammonia content value at the outlet, and determine whether the ammonia slip rate value is lower than the set ammonia slip rate value.

[0042] The adjustment module is used to adjust the initial ammonia injection amount according to the ammonia content at the outlet to obtain the final ammonia injection amount if the ammonia slip rate value is not lower than the set ammonia slip rate value.

[0043] The advantages of the method and apparatus for reducing ammonia injection in an SCR denitrification system of the present invention compared with the prior art are as follows:

[0044] This invention utilizes advanced prediction algorithms and sensor technology to achieve real-time monitoring and prediction of NOx content in flue gas. The system calculates based on the monitoring and prediction, dynamically adjusting the ammonia injection rate to maintain optimal matching with the NOx content, reducing ammonia escape, significantly lowering the operating cost of the SCR system, improving its denitrification efficiency, and reducing environmental impact. Attached Figure Description

[0045] Figure 1 This is a schematic diagram of a method for reducing ammonia injection in an SCR denitrification system according to an embodiment of the present invention;

[0046] Figure 2 This is a schematic diagram of the composition of an ammonia injection device in an SCR denitrification system according to an embodiment of the present invention. Detailed Implementation

[0047] The specific embodiments of the present invention will be described in further detail below with reference to the accompanying drawings and examples. The following examples are for illustrative purposes only and are not intended to limit the scope of the invention.

[0048] In the description of this application, it should be understood that the terms "center", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0049] The terms “second” and “second” are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined with “second” or “second” may explicitly or implicitly include one or more of that feature. In the description of this application, unless otherwise stated, “multiple” means two or more.

[0050] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection between two components. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0051] like Figure 1 As shown in the embodiments of this application, a method for reducing ammonia injection in an SCR denitrification system is provided, including: S100: using a prediction model to predict the NO at the inlet of the SCR denitrification system. X The content of NO at the inlet was predicted. X Content prediction value; S200: Calculate the NO content at the inlet. X Real-time content value and NO at the inlet XS300: Obtain the ammonia content value at the outlet of the SCR denitrification system, and calculate the ammonia slip rate of the SCR denitrification system based on the initial ammonia injection rate and the ammonia content value at the outlet, while determining whether the ammonia slip rate value is lower than the set ammonia slip rate value; S400: If the ammonia slip rate value is not lower than the set ammonia slip rate value, adjust the initial ammonia injection rate based on the ammonia content value at the outlet to obtain the final ammonia injection rate.

[0052] Furthermore, this invention employs advanced prediction algorithms and sensor technology to achieve real-time monitoring and prediction of NOx content in flue gas. The system calculates based on the monitoring and prediction, dynamically adjusting the ammonia injection rate to maintain optimal matching with the NOx content, reducing ammonia escape, significantly lowering the operating cost of the SCR system, improving its denitrification efficiency, and reducing environmental impact.

[0053] In embodiments of this application, a method for reducing ammonia injection in an SCR denitrification system is provided, wherein the NO at the inlet of the SCR denitrification system is predicted using a predictive model. X The content of NO at the inlet was predicted. X Before determining the predicted NO content, the process includes: acquiring historical operating data of the generator set and constructing a prediction model based on the historical operating data; acquiring the NO content at the inlet of the SCR denitrification system. X Real-time content value, based on the NO at the inlet. X The real-time content value is used to correct the prediction model; the NO at the inlet is then predicted using the corrected prediction model. X Content prediction value.

[0054] In embodiments of this application, a method for reducing ammonia injection in an SCR denitrification system is provided, wherein the NO at the inlet is calculated. X Real-time content value and NO at the inlet X The average value of the predicted content is used to set the initial ammonia injection rate of the SCR denitrification system based on the average value, specifically including: calculating the NO content at the inlet. X Real-time content value and NO at the inlet X The average value of the predicted content; calculate the difference between the average value and the set standard average value, and set the initial ammonia injection rate of the SCR denitrification system according to the magnitude of the difference.

[0055] In embodiments of this application, a method for reducing ammonia injection in an SCR denitrification system is provided, comprising calculating the difference between the average value and a set standard average value, and setting the initial ammonia injection amount of the SCR denitrification system based on the magnitude of the difference, including:

[0056] A standard average value G0 is preset, and a first preset difference g1, a second preset difference g2, a third preset difference g3 and a fourth preset difference g4 are set, where g1 < g2 < g3 < g4. A first preset ammonia injection amount A1, a second preset ammonia injection amount A2, a third preset ammonia injection amount A3 and a fourth preset ammonia injection amount A4 are also set, where A1 < A2 < A3 < A4.

[0057] The initial ammonia injection rate Ai of the SCR denitrification system is set according to the magnitude of the difference gi, where i = 1, 2, 3, 4;

[0058] When △G-G0≤g1, the first preset ammonia injection amount A1 is selected as the initial ammonia injection amount;

[0059] When g1 < ΔG - G0 ≤ g2, the second preset ammonia injection amount A2 is selected as the initial ammonia injection amount;

[0060] When g2 < ΔG - G0 ≤ g3, the third preset ammonia injection amount A3 is selected as the initial ammonia injection amount;

[0061] When g3 < △G - G0 ≤ g4, the fourth preset ammonia injection amount A4 is selected as the initial ammonia injection amount.

[0062] In an embodiment of this application, a method for reducing ammonia injection in an SCR denitrification system is provided. The method involves obtaining the ammonia content at the outlet of the SCR denitrification system, calculating the ammonia slip rate of the SCR denitrification system based on the initial ammonia injection rate and the outlet ammonia content, and simultaneously determining whether the ammonia slip rate is lower than a set ammonia slip rate value. This includes: obtaining the ammonia content at the outlet of the SCR denitrification system, calculating the ammonia slip rate of the SCR denitrification system based on the initial ammonia injection rate and the outlet ammonia content; determining whether the ammonia slip rate is lower than a set ammonia slip rate value; if the ammonia slip rate is lower than the set ammonia slip rate value, no adjustment to the initial ammonia injection rate is required; if the ammonia slip rate is not lower than the set ammonia slip rate value, the initial ammonia injection rate needs to be adjusted.

[0063] In embodiments of this application, a method for reducing ammonia injection in an SCR denitrification system is provided. If the ammonia slip rate is not lower than a set ammonia slip rate, the initial ammonia injection amount is adjusted based on the ammonia content at the outlet to obtain the final ammonia injection amount. This includes:

[0064] If the ammonia slip rate value is not lower than the set ammonia slip rate value, then obtain the ammonia content value ΔT at the outlet of the SCR denitrification system;

[0065] Set a first preset ammonia content value T1, a second preset ammonia content value T2, a third preset ammonia content value T3, and a fourth preset ammonia content value T4, where T1 < T2 < T3 < T4.

[0066] Set a first preset adjustment coefficient x1, a second preset adjustment coefficient x2, a third preset adjustment coefficient x3 and a fourth preset adjustment coefficient x4, and 1 < x1 < x2 < x3 < x4 < 1.5;

[0067] Based on the relationship between the obtained ammonia content value ΔT at the outlet and each preset ammonia content value Ti, a preset adjustment coefficient is selected to adjust the working conditions in the preset working condition matrix Ai.

[0068] When T1 < △T ≤ T2, the first preset adjustment coefficient x1 is selected to adjust the first preset ammonia injection quantity Ai, and the adjusted quantity is Ai * x1.

[0069] When T2 < △T ≤ T3, the second preset adjustment coefficient x2 is selected to adjust the second preset ammonia injection quantity Ai, and the adjusted quantity is Ai * x2.

[0070] When T3 < △T ≤ T4, the third preset adjustment coefficient x3 is selected to adjust the third preset ammonia injection quantity Ai, and the adjusted quantity is Ai * x3.

[0071] When T4 < △T, the fourth preset adjustment coefficient x4 is selected to adjust the fourth preset ammonia injection quantity Ai, and the adjusted quantity is Ai * x4.

[0072] In an embodiment of this application, a method for reducing ammonia injection in an SCR denitrification system is provided, wherein the ammonia content at the outlet of the SCR denitrification system is the average ammonia content at the outlet of each flue of the SCR denitrification system.

[0073] like Figure 2 As shown in the embodiments of this application, a device for reducing ammonia injection in an SCR denitrification system is provided, comprising: a prediction module, used to predict the NO at the inlet of the SCR denitrification system using a prediction model. X The content of NO at the inlet was predicted. X Content prediction value; setting module, used to calculate NO at the inlet. X Real-time content value and NO at the inlet XThe system uses an average value of the predicted ammonia content to set the initial ammonia injection rate for the SCR denitrification system; a judgment module to obtain the ammonia content value at the outlet of the SCR denitrification system, calculate the ammonia slip rate value of the SCR denitrification system based on the initial ammonia injection rate and the ammonia content value at the outlet, and determine whether the ammonia slip rate value is lower than the set ammonia slip rate value; and an adjustment module to adjust the initial ammonia injection rate to obtain the final ammonia injection rate if the ammonia slip rate value is not lower than the set ammonia slip rate value.

[0074] In summary, embodiments of the present invention provide a method and apparatus for reducing ammonia injection in an SCR denitrification system, comprising: using a predictive model to reduce NO at the inlet of the SCR denitrification system. X The content of NO at the inlet was predicted. X Predicted content value; calculate NO at the inlet. X Real-time content value and NO at the inlet X The invention employs advanced prediction algorithms and sensor technology to achieve real-time monitoring and prediction of NOx content in flue gas. Based on this monitoring and prediction, the initial ammonia injection rate of the SCR denitrification system is set. The ammonia content at the outlet of the SCR denitrification system is obtained, and the ammonia slip rate is calculated using the initial injection rate and the outlet ammonia content. Simultaneously, it is determined whether the ammonia slip rate is lower than the set ammonia slip rate. If the ammonia slip rate is not lower than the set ammonia slip rate, the initial injection rate is adjusted according to the outlet ammonia content to obtain the final injection rate.

[0075] Finally, it should be noted that those skilled in the art can obviously make various modifications and variations to this invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims and their equivalents, this invention also intends to include these modifications and variations.

[0076] The above description is merely one embodiment of the present invention, and should not be construed as limiting the scope of the invention. Any structural changes made based on the present invention, as long as they do not depart from the essence of the invention, should be considered as falling within the protection scope of the present invention and subject to its restrictions. Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the specific working process and related descriptions of the system described above can be referred to the corresponding processes in the foregoing method embodiments, and will not be repeated here.

[0077] The term "comprising" or any other similar term is intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus / device that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent in such process, method, article, or apparatus / device.

[0078] The technical solutions of the present invention have been described above with reference to the accompanying drawings and further embodiments. However, it will be readily understood by those skilled in the art that the scope of protection of the present invention is obviously not limited to these specific embodiments. Without departing from the principles of the present invention, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after such changes or substitutions will all fall within the scope of protection of the present invention.

[0079] The above description is merely a preferred embodiment of the present invention and is not intended to limit the scope of protection of the present invention.

Claims

1. A method for reducing ammonia injection in an SCR denitrification system, characterized in that, include: The NO at the inlet of the SCR denitrification system was predicted using a predictive model. X The content of NO at the inlet was predicted. X Content prediction value; Calculate NO at the entrance X Real-time content value and NO at the inlet X The average value of the predicted content is used to set the initial ammonia injection rate of the SCR denitrification system; Obtain the ammonia content value at the outlet of the SCR denitrification system, and calculate the ammonia slip rate value of the SCR denitrification system based on the initial ammonia injection rate and the ammonia content value at the outlet. At the same time, determine whether the ammonia slip rate value is lower than the set ammonia slip rate value. If the ammonia slip rate value is not lower than the set ammonia slip rate value, the initial ammonia injection amount is adjusted according to the ammonia content value at the outlet to obtain the final ammonia injection amount; The calculation of NO at the inlet X Real-time content value and NO at the inlet X The average value of the predicted content, and the initial ammonia injection rate of the SCR denitrification system is set based on the average value, specifically including: Calculate NO at the entrance X Real-time content value and NO at the inlet X The average of the predicted content values; Calculate the difference between the average value and the set standard average value, and set the initial ammonia injection rate of the SCR denitrification system based on the magnitude of the difference; The calculation of the difference between the average value and the set standard average value, and the setting of the initial ammonia injection rate of the SCR denitrification system based on the magnitude of the difference, includes: A standard average value G0 is preset, and a first preset difference g1, a second preset difference g2, a third preset difference g3 and a fourth preset difference g4 are set, where g1 < g2 < g3 < g4. A first preset ammonia injection amount A1, a second preset ammonia injection amount A2, a third preset ammonia injection amount A3 and a fourth preset ammonia injection amount A4 are also set, where A1 < A2 < A3 < A4. The initial ammonia injection rate Ai of the SCR denitrification system is set according to the magnitude of the difference gi, where i = 1, 2, 3, 4; When △G-G0≤g1, the first preset ammonia injection amount A1 is selected as the initial ammonia injection amount; When g1 < △G-G0 ≤ g2, the second preset ammonia injection amount A2 is selected as the initial ammonia injection amount; When g2 < ΔG - G0 ≤ g3, the third preset ammonia injection amount A3 is selected as the initial ammonia injection amount; When g3 < △G - G0 ≤ g4, the fourth preset ammonia injection amount A4 is selected as the initial ammonia injection amount; The process of obtaining the ammonia content at the outlet of the SCR denitrification system, calculating the ammonia slip rate of the SCR denitrification system based on the initial ammonia injection rate and the ammonia content at the outlet, and simultaneously determining whether the ammonia slip rate is lower than the set ammonia slip rate value includes: Obtain the ammonia content at the outlet of the SCR denitrification system, and calculate the ammonia slip rate of the SCR denitrification system based on the initial ammonia injection rate and the ammonia content at the outlet. Determine whether the ammonia slip rate value is lower than the set ammonia slip rate value; If the ammonia slip rate is lower than the set ammonia slip rate, then there is no need to adjust the initial ammonia injection amount; If the ammonia slip rate is not lower than the set ammonia slip rate, the initial ammonia injection amount needs to be adjusted.

2. The method for reducing ammonia injection in an SCR denitrification system according to claim 1, characterized in that, The prediction model is used to analyze the NO at the inlet of the SCR denitrification system. X The content of NO at the inlet was predicted. X Prior to the predicted content values, including: Obtain historical operating data of the generator set and construct a prediction model based on the historical operating data; Obtain NO at the inlet of the SCR denitrification system X Real-time content value, based on the NO at the inlet. X The real-time content values ​​are used to correct the prediction model; The NO at the inlet is predicted using the corrected prediction model. X Content prediction value.

3. The method for reducing ammonia injection in an SCR denitrification system according to claim 1, characterized in that, The ammonia content at the outlet of the SCR denitrification system is the average ammonia content at the outlet of each flue of the SCR denitrification system.

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