Intelligent ammonia gas injection control system and method

Abstract

The invention relates to the technical field of flue gas denitration, and discloses an intelligent ammonia gas injection control system and method.The intelligent ammonia gas injection control system is characterized in that an ammonia gas injection module is used for providing ammonia gas needed by denitration reaction into an SCR device; the data acquisition module is used for acquiring required data in real time; the control module is used for controlling the ammonia gas injection module to inject ammonia gas with different flows into the SCR device according to the data acquired by the data acquisition module; the control unit is used for selecting the initial ammonia gas injection flow according to the flue gas flow in the SCR device; the safety buffer unit is used for judging whether to correct the initial ammonia gas injection flow or not according to the current data in the SCR device after the ammonia gas injection module injects the ammonia gas according to the initial ammonia gas injection flow; and the risk elimination module is used for collecting the concentration of nitric oxide in the flue gas at the gas outlet in real time, judging whether the SCR device needs to be controlled again or not after the control module performs control, and realizing more precise control on ammonia gas injection through multiple negative feedback cycles.

Description

Technical Field

[0001] The present invention relates to the technical field of flue gas denitration, and in particular to an intelligent ammonia injection control system and method. Background Art

[0002] With the rapid development of modern industrial production and the continuous improvement of people's living standards, air pollution has gradually become a focus of people's attention. The emission of a large amount of industrial waste gas has caused the concentration of pollutants in the air to continue to rise, posing a serious threat to the ecological environment and human health. As one of the main air pollutants, nitrogen oxides (NOx) in flue gas are an important factor leading to environmental problems such as acid rain, photochemical smog, and ozone reduction. With the enhancement of environmental protection awareness and the introduction of relevant laws and regulations, the restrictions on NOx emissions in industrial flue gas have become increasingly stringent. SCR flue gas denitrification technology has emerged as the times require, which can reduce NOx in flue gas to below the limit required by regulations, and at the same time reduce the emission of other pollutants. It has the advantages of high efficiency, stability and reliability. However, in practical applications, ammonia is an important reducing agent in the SCR reaction, and its injection amount has an important influence on the SCR reaction. Excessive ammonia injection will lead to ammonia escape, which will not only cause waste of reducing agent, but also cause secondary harm to the environment; too little ammonia injection will lead to incomplete denitrification and cannot effectively achieve flue gas purification.

[0003] The traditional ammonia injection control system selects a fixed ammonia injection flow rate according to the nitrogen oxide concentration in the device, ignoring that the flue gas temperature and flue gas flow rate are also important influencing factors in the denitrification reaction. At the same time, the control system has a poor effect, and cannot effectively control the ammonia injection amount, and cannot effectively confirm whether the denitrification reaction is complete, and whether there is any escape of the reducing agent, which often results in incomplete purification of the flue gas, or even the escape of the reducing agent, causing secondary damage to the environment. Summary of the invention

[0004] The embodiment of the present invention provides an intelligent ammonia injection control system and method, in which the intelligent control of ammonia injection is realized to prevent ammonia escape while ensuring sufficient reaction, so as to solve the technical problem of lack of precision of ammonia injection control in SCR denitrification technology in the prior art.

[0005] In order to achieve the above object, the present invention provides an intelligent ammonia injection control system, comprising:

[0006] Ammonia injection module, used to provide ammonia required for denitration reaction into the SCR device;

[0007] Data acquisition module, used for real-time acquisition of nitrogen oxide concentration in the SCR device, ammonia concentration in the SCR device, temperature in the SCR device, flue gas flow, flue gas temperature and flue gas pressure in the SCR device;

[0008] A control module, used for controlling the ammonia injection module to inject ammonia with different flow rates into the SCR device according to the data collected by the data acquisition module;

[0009] The control module also includes a control unit and a safety buffer unit that are interconnected;

[0010] The control unit selects an initial ammonia injection flow rate according to the flue gas flow rate in the SCR device and a preset ammonia injection rule;

[0011] The safety buffer unit determines whether to correct the initial ammonia injection flow rate according to the current nitrogen oxide concentration in the SCR device and the ammonia concentration in the SCR device after the ammonia injection module injects ammonia according to the initial ammonia injection flow rate;

[0012] The safety buffer unit further determines whether the temperature inside the SCR device needs to be adjusted according to the relationship between the temperature inside the SCR device and a preset temperature range;

[0013] The risk elimination module is arranged in the air outlet of the SCR device and collects the nitrogen oxide concentration in the flue gas at the air outlet in real time. The risk elimination module is used to determine whether the SCR device needs to be corrected and controlled again according to the collected real-time data after the control module is controlled.

[0014] Furthermore, the initial ammonia injection flow rate is selected according to the flue gas flow rate in the SCR device and the preset ammonia injection rule, specifically:

[0015] Preset a first preset smoke flow rate and a second preset smoke flow rate; wherein the first preset smoke flow rate is smaller than the second preset smoke flow rate;

[0016] Presetting a first ammonia injection flow rate, a second ammonia injection flow rate, and a third ammonia injection flow rate; wherein the first ammonia injection flow rate is smaller than the second ammonia injection flow rate, and the second ammonia injection flow rate is smaller than the third ammonia injection flow rate;

[0017] When the flue gas flow rate in the SCR device is less than the first preset flue gas flow rate, the first ammonia injection flow rate is selected as the initial ammonia injection flow rate;

[0018] When the flue gas flow rate in the SCR device is greater than or equal to the first preset flue gas flow rate and less than the second preset flue gas flow rate, the second ammonia injection flow rate is selected as the initial ammonia injection flow rate;

[0019] When the flue gas flow rate in the SCR device is greater than or equal to the second preset flue gas flow rate, the third ammonia injection flow rate is selected as the initial ammonia injection flow rate.

[0020] Further, after the ammonia injection module injects ammonia according to the initial ammonia injection flow rate, judging whether to correct the initial ammonia injection flow rate according to the current nitrogen oxide concentration in the SCR device and the ammonia concentration in the SCR device includes:

[0021] Setting a preset nitrogen oxide concentration threshold and a preset ammonia concentration threshold;

[0022] When the current nitrogen oxide concentration in the SCR device is lower than the preset nitrogen oxide concentration threshold, and the current ammonia concentration in the SCR device is lower than the preset ammonia concentration threshold, it is determined that no correction is required;

[0023] When the current nitrogen oxide concentration in the SCR device is higher than the preset nitrogen oxide concentration threshold, or the current ammonia concentration in the SCR device is higher than the preset ammonia concentration threshold, it is determined that correction is required.

[0024] Further, when the current nitrogen oxide concentration in the SCR device is higher than the preset nitrogen oxide concentration threshold, or the current ammonia concentration in the SCR device is higher than the preset ammonia concentration threshold, it is determined that correction is required, including:

[0025] Acquire the current flue gas flow, flue gas temperature, flue gas pressure, and nitrogen oxide concentration in the SCR device, and correct the initial ammonia injection flow;

[0026] The current nitrogen oxide concentration in the SCR device includes: the current NO concentration in the SCR device and the current NO2 concentration in the SCR device.

[0027] Furthermore, the initial ammonia injection flow rate is corrected by obtaining the current flue gas flow rate, flue gas pressure, flue gas temperature and nitrogen oxide concentration in the SCR device, including:

[0028]

[0029] in, is the corrected ammonia injection flow rate, V q is the flue gas flow rate, C NO is the NO concentration in the current SCR device, is the NO2 concentration in the current SCR device, is the stoichiometric coefficient of NH3 in the reaction, n NOis the stoichiometric coefficient of NO in the reaction, is the stoichiometric coefficient of NO2 in the reaction, a is the flue gas temperature, and P is the flue gas pressure.

[0030] Furthermore, it also includes:

[0031] An alarm device is connected to the control module, and sends a warning message when the nitrogen oxide concentration in the current SCR device is higher than the preset nitrogen oxide concentration threshold, or the ammonia concentration in the current SCR device is higher than the preset ammonia concentration threshold, so as to warn of abnormal denitration reaction.

[0032] Further, determining whether the temperature inside the SCR device needs to be adjusted according to the relationship between the temperature inside the SCR device and a preset temperature range includes:

[0033] When the temperature in the SCR device is lower than a preset temperature range, the safety buffer unit sends a temperature increase signal to the control unit, and the control unit turns on the heating plate in the SCR device;

[0034] When the temperature in the SCR device is higher than a preset temperature range, the safety buffer unit sends a temperature reduction signal to the control unit, and the control unit turns on the atomizing nozzle in the SCR device to spray urea into the SCR device.

[0035] Furthermore, judging whether it is necessary to perform correction control on the SCR device again according to the collected real-time data includes:

[0036] Collect the nitrogen oxide concentration in the flue gas at multiple times;

[0037] Setting a first preset nitrogen oxide concentration W1 and a second preset nitrogen oxide concentration W2, wherein the first preset nitrogen oxide concentration W1 is less than the second preset nitrogen oxide concentration W2;

[0038] Constructing a first concentration interval (0, W1), a second concentration interval [W1, W2] and a third concentration interval (W2, +∞);

[0039] It is determined whether the SCR device needs to be corrected and controlled again according to the first concentration range, the second concentration range, and the third concentration range.

[0040] Further, judging whether it is necessary to perform correction control on the SCR device again according to the first concentration interval, the second concentration interval and the third concentration interval includes:

[0041] When the nitrogen oxide concentration in the flue gas is ∈(0, W1), it is judged that the nitrogen oxide concentration in the flue gas is within the allowable error;

[0042] When the nitrogen oxide concentration in the flue gas ∈ [W1, W2], it is determined that the nitrogen oxide concentration in the flue gas is not within the allowable error, and the first nitrogen oxide variation coefficient is calculated:

[0043]

[0044] Wherein, E1 is the first nitrogen oxide variation coefficient, m is the number of nitrogen oxide concentrations in the flue gas within the second concentration range, and Y j is the concentration of nitrogen oxides in the j-th flue gas;

[0045] When the nitrogen oxide concentration in the flue gas is ∈(W2, +∞), it is determined that the nitrogen oxide concentration in the flue gas is not within the allowable error, the second preset nitrogen oxide concentration and all the nitrogen oxide concentrations in the flue gas are normalized, the normalized second preset nitrogen oxide concentration is eliminated, and the ratio of the constant 1 to all the remaining normalized nitrogen oxide concentrations in the flue gas is calculated;

[0046] Extract a maximum nitrogen oxide concentration ratio in the flue gas and a minimum nitrogen oxide concentration ratio in the flue gas from all the nitrogen oxide concentration ratios in the flue gas;

[0047] Calculating the difference between the maximum flue gas nitrogen oxide concentration ratio and the minimum flue gas nitrogen oxide concentration ratio;

[0048] Calculate the second difference between each nitrogen oxide concentration ratio in the flue gas and the difference respectively;

[0049] Calculate the second difference average of all second differences and calculate the second nitrogen oxide variation coefficient:

[0050]

[0051] Wherein, E2 is the second nitrogen oxide variation coefficient, m2 is the number of the second difference, g i is the ith second difference, t is the second difference average, X is the normalized second preset nitrogen oxide concentration, and ξ is the adjustment coefficient;

[0052] A secondary correction is performed on the ammonia injection flow rate according to the first nitrogen oxide variation coefficient and the second nitrogen oxide variation coefficient.

[0053] In order to achieve the above object, the present invention also provides an intelligent ammonia injection control method, comprising:

[0054] Real-time collection of nitrogen oxide concentration, ammonia concentration, temperature, flue gas flow, flue gas temperature and flue gas pressure in the SCR device;

[0055] Selecting an initial ammonia injection flow rate according to the flue gas flow rate in the SCR device and a preset ammonia injection rule;

[0056] After injecting ammonia according to the initial ammonia injection flow rate, judging whether to correct the initial ammonia injection flow rate according to the current nitrogen oxide concentration in the SCR device and the ammonia concentration in the SCR device; judging whether to adjust the temperature in the SCR device according to the relationship between the temperature in the SCR device and the preset temperature range;

[0057] The concentration of nitrogen oxides in the flue gas at the outlet is collected in real time, and it is determined whether the SCR device needs to be corrected and controlled again based on the collected real-time data.

[0058] Compared with the prior art, the present invention has the following beneficial effects:

[0059] The present invention discloses an intelligent ammonia injection control system and method, which performs more intelligent regulation on the ammonia injection flow rate in the SCR device, collects various data in the device in real time, selects a preset injection flow rate through real-time data, and then continuously corrects it according to the real-time data. Finally, a risk elimination module determines whether a secondary correction of the ammonia injection flow rate is required. Through multiple negative feedback cycles, a more accurate control of the ammonia injection flow rate is finally achieved, thereby realizing safer and more intelligent flue gas denitrification. BRIEF DESCRIPTION OF THE DRAWINGS

[0060] Various other advantages and benefits will become apparent to those of ordinary skill in the art by reading the detailed description of the preferred embodiments below. The accompanying drawings are only for the purpose of illustrating the preferred embodiments and are not to be considered as limiting the present invention. Moreover, the same reference symbols are used throughout the accompanying drawings to represent the same components. In the accompanying drawings:

[0061] Figure 1 A schematic diagram of the structure of an intelligent ammonia injection control system according to an embodiment of the present invention is shown;

[0062] Figure 2 A schematic flow chart of an intelligent ammonia injection control method in an embodiment of the present invention is shown. DETAILED DESCRIPTION

[0063] The specific implementation of the present invention is further described in detail below in conjunction with the accompanying drawings and examples. The following examples are used to illustrate the present invention, but are not intended to limit the scope of the present invention.

[0064] In the description of the present application, it should be understood that the terms "center", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.

[0065] The terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of this application, unless otherwise specified, "plurality" means two or more.

[0066] In the description of this application, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0067] The following is a description of preferred embodiments of the present invention with reference to the accompanying drawings.

[0068] like Figure 1 As shown, an embodiment of the present invention discloses an intelligent ammonia injection control system, comprising:

[0069] Ammonia injection module, used to provide ammonia required for denitration reaction into the SCR device;

[0070] Data acquisition module, used for real-time acquisition of nitrogen oxide concentration in the SCR device, ammonia concentration in the SCR device, temperature in the SCR device, flue gas flow, flue gas temperature and flue gas pressure in the SCR device;

[0071] A control module, used for controlling the ammonia injection module to inject ammonia of different flow rates into the SCR device according to the data collected by the data acquisition module;

[0072] The control module also includes a control unit and a safety buffer unit that are interconnected;

[0073] A control unit selects an initial ammonia injection flow rate according to the flue gas flow rate in the SCR device and a preset ammonia injection rule;

[0074] A safety buffer unit, after the ammonia injection module injects ammonia according to the initial ammonia injection flow rate, determines whether to correct the initial ammonia injection flow rate according to the current nitrogen oxide concentration in the SCR device and the ammonia concentration in the SCR device;

[0075] The safety buffer unit also determines whether the temperature inside the SCR device needs to be adjusted based on the relationship between the temperature inside the SCR device and the preset temperature range;

[0076] The risk elimination module is arranged in the air outlet of the SCR device and collects the nitrogen oxide concentration in the flue gas at the air outlet in real time. The risk elimination module is used to determine whether the SCR device needs to be corrected and controlled again according to the collected real-time data after the control module controls it.

[0077] In this embodiment, a multiple feedback system is provided to more accurately detect abnormal nitrogen oxide concentration in the SCR device, thereby timely correcting the ammonia injection flow rate and achieving efficient flue gas denitrification.

[0078] In some embodiments of the present application, the initial ammonia injection flow rate is selected according to the flue gas flow rate in the SCR device and the preset ammonia injection rule, specifically:

[0079] Presetting a first preset smoke flow rate and a second preset smoke flow rate; wherein the first preset smoke flow rate is smaller than the second preset smoke flow rate;

[0080] Presetting a first ammonia injection flow rate, a second ammonia injection flow rate, and a third ammonia injection flow rate; wherein the first ammonia injection flow rate is smaller than the second ammonia injection flow rate, and the second ammonia injection flow rate is smaller than the third ammonia injection flow rate;

[0081] When the flue gas flow rate in the SCR device is less than the first preset flue gas flow rate, the first ammonia injection flow rate is selected as the initial ammonia injection flow rate;

[0082] When the flue gas flow rate in the SCR device is greater than or equal to the first preset flue gas flow rate and less than the second preset flue gas flow rate, the second ammonia injection flow rate is selected as the initial ammonia injection flow rate;

[0083] When the flue gas flow rate in the SCR device is greater than or equal to the second preset flue gas flow rate, the third ammonia injection flow rate is selected as the initial ammonia injection flow rate.

[0084] The beneficial effect of the above technical solution is: according to the different flue gas flow rates, the appropriate ammonia injection flow rate is selected to ensure that the amount of ammonia in the SCR device is sufficient at the initial startup moment; thereby avoiding a serious mismatch between the nitrogen oxide concentration in the device and the ammonia concentration in the device at the initial startup moment of the SCR device, resulting in poor denitrification effect at the initial moment.

[0085] In some embodiments of the present application, after the ammonia injection module injects ammonia according to the initial ammonia injection flow rate, it is determined whether to correct the initial ammonia injection flow rate according to the current nitrogen oxide concentration in the SCR device and the ammonia concentration in the SCR device, including:

[0086] Setting a preset nitrogen oxide concentration threshold and a preset ammonia concentration threshold;

[0087] When the current nitrogen oxide concentration in the SCR device is lower than the preset nitrogen oxide concentration threshold, and the current ammonia concentration in the SCR device is lower than the preset ammonia concentration threshold, it is determined that no correction is required;

[0088] When the current nitrogen oxide concentration in the SCR device is higher than a preset nitrogen oxide concentration threshold, or the current ammonia concentration in the SCR device is higher than a preset ammonia concentration threshold, it is determined that correction is required.

[0089] In this embodiment, while monitoring the nitrogen oxide concentration in the SCR device, the ammonia concentration in the SCR device is also monitored to prevent unnecessary waste of excessive reducing agent. The ammonia injection flow rate is preliminarily corrected based on the feedback of the nitrogen oxide concentration and the ammonia concentration.

[0090] In some embodiments of the present application, when the current nitrogen oxide concentration in the SCR device is higher than a preset nitrogen oxide concentration threshold, or the current ammonia concentration in the SCR device is higher than a preset ammonia concentration threshold, it is determined that correction is required, including:

[0091] Obtain the current flue gas flow, flue gas temperature, flue gas pressure, and nitrogen oxide concentration in the SCR device, and correct the initial ammonia injection flow;

[0092] The current nitrogen oxide concentration in the SCR device includes: the current NO concentration in the SCR device and the current NO2 concentration in the SCR device.

[0093] In this embodiment, the initial ammonia injection flow rate is corrected by obtaining the current flue gas flow rate, flue gas pressure, flue gas temperature and the current nitrogen oxide concentration in the SCR device, including:

[0094]

[0095] in, is the corrected ammonia injection flow rate, V q is the flue gas flow rate, C NO is the NO concentration in the current SCR device, is the NO2 concentration in the current SCR device, is the stoichiometric coefficient of NH3 in the reaction, n NO is the stoichiometric coefficient of NO in the reaction, is the stoichiometric coefficient of NO2 in the reaction, a is the flue gas temperature, and P is the flue gas pressure.

[0096] The beneficial effects of the above technical solution are: listing flue gas as an important influencing factor affecting the denitrification effect, adjusting the ammonia injection flow rate more comprehensively, obtaining a reliable corrected ammonia injection flow rate based on the flue gas flow rate, flue gas pressure, and flue gas temperature, and using the newly obtained corrected ammonia injection flow rate to replace the initial ammonia injection flow rate.

[0097] In some embodiments of the present application, it also includes:

[0098] The alarm device is connected to the control module. When the nitrogen oxide concentration in the current SCR device is higher than the preset nitrogen oxide concentration threshold, or the ammonia concentration in the current SCR device is higher than the preset ammonia concentration threshold, a warning message is issued to warn of abnormal denitration reaction.

[0099] The beneficial effect of the above technical solution is that when an abnormal condition occurs in the data of the SCR device, an alarm is quickly issued through the alarm device so that the staff can monitor the correction process in real time and intervene manually when necessary.

[0100] In some embodiments of the present application, determining whether the temperature in the SCR device needs to be adjusted according to the relationship between the temperature in the SCR device and a preset temperature range includes:

[0101] When the temperature inside the SCR device is lower than the preset temperature range, the safety buffer unit sends a temperature increase signal to the control unit, and the control unit turns on the heating plate inside the SCR device;

[0102] When the temperature inside the SCR device is higher than the preset temperature range, the safety buffer unit sends a cooling signal to the control unit, and the control unit turns on the atomizing nozzle in the SCR device to spray urea into the SCR device.

[0103] In this embodiment, the temperature inside the SCR device is monitored in real time to avoid the phenomenon of reduced denitration efficiency caused by abnormal temperature, and to ensure that the temperature inside the device is always within a preset temperature range.

[0104] In some embodiments of the present application, judging whether it is necessary to perform correction control on the SCR device again according to the collected real-time data includes:

[0105] Collect the nitrogen oxide concentration in the flue gas at multiple times;

[0106] Setting a first preset nitrogen oxide concentration W1 and a second preset nitrogen oxide concentration W2, wherein the first preset nitrogen oxide concentration W1 is less than the second preset nitrogen oxide concentration W2;

[0107] Constructing a first concentration interval (0, W1), a second concentration interval [W1, W2] and a third concentration interval (W2, +∞);

[0108] It is determined whether the SCR device needs to be corrected and controlled again according to the first concentration range, the second concentration range, and the third concentration range.

[0109] In this embodiment, the concentration of nitrogen oxides in the flue gas at the gas outlet at multiple different times is collected, different concentration intervals are established, and each nitrogen oxide collected in the flue gas is classified and matched to different concentration intervals for comprehensive processing.

[0110] In this embodiment, judging whether it is necessary to perform correction control on the SCR device again according to the first concentration interval, the second concentration interval, and the third concentration interval includes:

[0111] When the concentration of nitrogen oxides in the flue gas is ∈(0, W1), it is judged that the concentration of nitrogen oxides in the flue gas is within the allowable error;

[0112] When the nitrogen oxide concentration in the flue gas ∈ [W1, W2], it is judged that the nitrogen oxide concentration in the flue gas is not within the allowable error, and the first nitrogen oxide variation coefficient is calculated:

[0113]

[0114] Where, E1 is the first nitrogen oxide variation coefficient, m is the number of nitrogen oxide concentrations in the flue gas within the second concentration range, and Y j is the concentration of nitrogen oxides in the jth flue gas;

[0115] When the nitrogen oxide concentration in the flue gas is ∈(W2, +∞), it is determined that the nitrogen oxide concentration in the flue gas is not within the allowable error, the second preset nitrogen oxide concentration and all the nitrogen oxide concentrations in the flue gas are normalized, the normalized second preset nitrogen oxide concentration is eliminated, and the ratio of the constant 1 to all the remaining normalized nitrogen oxide concentrations in the flue gas is calculated;

[0116] Extract a maximum nitrogen oxide concentration ratio in the flue gas and a minimum nitrogen oxide concentration ratio in the flue gas from all the nitrogen oxide concentration ratios in the flue gas;

[0117] Calculate the difference between the maximum flue gas nitrogen oxide concentration ratio and the minimum flue gas nitrogen oxide concentration ratio;

[0118] Calculate the second difference between the ratio and the difference of each nitrogen oxide concentration in the flue gas;

[0119] Calculate the second difference average of all second differences and calculate the second nitrogen oxide variation coefficient:

[0120]

[0121] Wherein, E2 is the second nitrogen oxide variation coefficient, m2 is the number of the second difference, g i is the ith second difference, t is the second difference average, X is the normalized second preset nitrogen oxide concentration, and ξ is the adjustment coefficient;

[0122] The ammonia injection flow rate is corrected secondary according to the first nitrogen oxide variation coefficient and the second nitrogen oxide variation coefficient.

[0123] In this embodiment, the ammonia injection flow rate is corrected based on the first nitrogen oxide change coefficient and the second nitrogen oxide change coefficient, and the current ammonia injection flow rate is corrected again based on the principle of corrected ammonia injection flow rate = [1 + (first nitrogen oxide coefficient + second nitrogen oxide coefficient)] × current ammonia injection flow rate.

[0124] The beneficial effects of the above technical solution are: using the risk discharge module to re-detect the nitrogen oxide concentration in the flue gas at the outlet and determine whether the ideal denitrification effect is achieved, ensuring the reliability of denitrification, preventing a single control method from causing poor denitrification effect, and ensuring the reliability of the denitrification effect through composite control and multi-level feedback.

[0125] In order to further explain the technical idea of ​​the present invention, the technical solution of the present invention is now described in combination with specific application scenarios.

[0126] Correspondingly, such as Figure 2 As shown, the present application also provides an intelligent ammonia injection control method, comprising:

[0127] S110: real-time collection of nitrogen oxide concentration in the SCR device, ammonia concentration in the SCR device, temperature in the SCR device, flue gas flow, flue gas temperature and flue gas pressure in the SCR device;

[0128] S120: selecting an initial ammonia injection flow rate according to the flue gas flow rate in the SCR device and a preset ammonia injection rule;

[0129] S130: after injecting ammonia according to the initial ammonia injection flow rate, judging whether to correct the initial ammonia injection flow rate according to the current nitrogen oxide concentration in the SCR device and the ammonia concentration in the SCR device; judging whether to adjust the temperature in the SCR device according to the relationship between the temperature in the SCR device and the preset temperature range;

[0130] S140: Collect the concentration of nitrogen oxides in the flue gas at the outlet in real time, and determine whether the SCR device needs to be corrected and controlled again based on the collected real-time data.

[0131] In the description of the above embodiments, specific features, structures, materials or characteristics may be combined in a suitable manner in any one or more embodiments or examples.

[0132] Although the present invention has been described above with reference to the embodiments, various modifications may be made thereto and parts thereof may be replaced with equivalents without departing from the scope of the present invention. In particular, as long as there is no structural conflict, the various features in the embodiments disclosed by the present invention may be used in combination with each other in any manner, and the fact that these combinations are not fully described in this specification is only for the sake of omitting space and saving resources.

[0133] Those skilled in the art can understand that the above are only preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art can still modify the technical solutions recorded in the aforementioned embodiments or replace some of the technical features therein by equivalents. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. An intelligent ammonia injection control system, characterized in that: include: Ammonia injection module, used to provide ammonia required for denitration reaction into the SCR device; Data acquisition module, used for real-time acquisition of nitrogen oxide concentration in the SCR device, ammonia concentration in the SCR device, temperature in the SCR device, flue gas flow, flue gas temperature and flue gas pressure in the SCR device; A control module, used for controlling the ammonia injection module to inject ammonia with different flow rates into the SCR device according to the data collected by the data acquisition module; The control module also includes a control unit and a safety buffer unit that are interconnected; The control unit selects an initial ammonia injection flow rate according to the flue gas flow rate in the SCR device and a preset ammonia injection rule; The safety buffer unit determines whether to correct the initial ammonia injection flow rate according to the current nitrogen oxide concentration in the SCR device and the ammonia concentration in the SCR device after the ammonia injection module injects ammonia according to the initial ammonia injection flow rate; The safety buffer unit further determines whether the temperature inside the SCR device needs to be adjusted according to the relationship between the temperature inside the SCR device and a preset temperature range; The risk elimination module is arranged in the air outlet of the SCR device and collects the nitrogen oxide concentration in the flue gas at the air outlet in real time. The risk elimination module is used to determine whether the SCR device needs to be corrected and controlled again according to the collected real-time data after the control module is controlled.

2. An intelligent ammonia injection control system according to claim 1, characterized in that: The initial ammonia injection flow rate is selected according to the flue gas flow rate in the SCR device and the preset ammonia injection rule, specifically: Preset a first preset smoke flow rate and a second preset smoke flow rate; wherein the first preset smoke flow rate is smaller than the second preset smoke flow rate; Presetting a first ammonia injection flow rate, a second ammonia injection flow rate, and a third ammonia injection flow rate; wherein the first ammonia injection flow rate is smaller than the second ammonia injection flow rate, and the second ammonia injection flow rate is smaller than the third ammonia injection flow rate; When the flue gas flow rate in the SCR device is less than the first preset flue gas flow rate, the first ammonia injection flow rate is selected as the initial ammonia injection flow rate; When the flue gas flow rate in the SCR device is greater than or equal to the first preset flue gas flow rate and less than the second preset flue gas flow rate, the second ammonia injection flow rate is selected as the initial ammonia injection flow rate; When the flue gas flow rate in the SCR device is greater than or equal to the second preset flue gas flow rate, the third ammonia injection flow rate is selected as the initial ammonia injection flow rate.

3. The intelligent ammonia injection control system according to claim 1, characterized in that: After the ammonia injection module injects ammonia according to the initial ammonia injection flow rate, judging whether to correct the initial ammonia injection flow rate according to the current nitrogen oxide concentration in the SCR device and the ammonia concentration in the SCR device includes: Setting a preset nitrogen oxide concentration threshold and a preset ammonia concentration threshold; When the current nitrogen oxide concentration in the SCR device is lower than the preset nitrogen oxide concentration threshold, and the current ammonia concentration in the SCR device is lower than the preset ammonia concentration threshold, it is determined that no correction is required; When the current nitrogen oxide concentration in the SCR device is higher than the preset nitrogen oxide concentration threshold, or the current ammonia concentration in the SCR device is higher than the preset ammonia concentration threshold, it is determined that correction is required.

4. The intelligent ammonia injection control system according to claim 3, characterized in that: When the current nitrogen oxide concentration in the SCR device is higher than the preset nitrogen oxide concentration threshold, or the current ammonia concentration in the SCR device is higher than the preset ammonia concentration threshold, it is determined that correction is required, including: Acquire the current flue gas flow, flue gas temperature, flue gas pressure, and nitrogen oxide concentration in the SCR device, and correct the initial ammonia injection flow; The current nitrogen oxide concentration in the SCR device includes: the current NO concentration in the SCR device and the current NO2 concentration in the SCR device.

5. The intelligent ammonia injection control system according to claim 4, characterized in that: Obtaining the current flue gas flow, flue gas pressure, flue gas temperature and nitrogen oxide concentration in the SCR device to correct the initial ammonia injection flow, including: in, is the corrected ammonia injection flow rate, V q is the flue gas flow rate, C NO is the NO concentration in the current SCR device, is the NO2 concentration in the current SCR device, is the stoichiometric coefficient of NH3 in the reaction, n NO is the stoichiometric coefficient of NO in the reaction, is the stoichiometric coefficient of NO2 in the reaction, a is the flue gas temperature, and P is the flue gas pressure.

6. The intelligent ammonia injection control system according to claim 3, characterized in that: Also includes: An alarm device is connected to the control module, and sends a warning message when the nitrogen oxide concentration in the current SCR device is higher than the preset nitrogen oxide concentration threshold, or the ammonia concentration in the current SCR device is higher than the preset ammonia concentration threshold, so as to warn of abnormal denitration reaction.

7. The intelligent ammonia injection control system according to claim 1, characterized in that: Determining whether the temperature inside the SCR device needs to be adjusted according to the relationship between the temperature inside the SCR device and a preset temperature range includes: When the temperature in the SCR device is lower than a preset temperature range, the safety buffer unit sends a temperature increase signal to the control unit, and the control unit turns on the heating plate in the SCR device; When the temperature in the SCR device is higher than a preset temperature range, the safety buffer unit sends a temperature reduction signal to the control unit, and the control unit turns on the atomizing nozzle in the SCR device to spray urea into the SCR device.

8. The intelligent ammonia injection control system according to claim 1, characterized in that: The determining whether the SCR device needs to be corrected and controlled again according to the collected real-time data includes: Collect the nitrogen oxide concentration in the flue gas at multiple times; Setting a first preset nitrogen oxide concentration W1 and a second preset nitrogen oxide concentration W2, wherein the first preset nitrogen oxide concentration W1 is less than the second preset nitrogen oxide concentration W2; Constructing a first concentration interval (0, W1), a second concentration interval [W1, W2] and a third concentration interval (W2, +∞); It is determined whether the SCR device needs to be corrected and controlled again according to the first concentration range, the second concentration range, and the third concentration range.

9. The intelligent ammonia injection control system according to claim 8, characterized in that: The determining whether it is necessary to perform correction control on the SCR device again according to the first concentration interval, the second concentration interval, and the third concentration interval includes: When the nitrogen oxide concentration in the flue gas is ∈(0, W1), it is judged that the nitrogen oxide concentration in the flue gas is within the allowable error; When the nitrogen oxide concentration in the flue gas ∈ [W1, W2], it is determined that the nitrogen oxide concentration in the flue gas is not within the allowable error, and the first nitrogen oxide variation coefficient is calculated: Wherein, E1 is the first nitrogen oxide variation coefficient, m is the number of nitrogen oxide concentrations in the flue gas within the second concentration interval, and Y j is the concentration of nitrogen oxides in the j-th flue gas; When the nitrogen oxide concentration in the flue gas is ∈(W2, +∞), it is determined that the nitrogen oxide concentration in the flue gas is not within the allowable error, the second preset nitrogen oxide concentration and all the nitrogen oxide concentrations in the flue gas are normalized, the normalized second preset nitrogen oxide concentration is eliminated, and the ratio of the constant 1 to all the remaining normalized nitrogen oxide concentrations in the flue gas is calculated; Extract a maximum nitrogen oxide concentration ratio in the flue gas and a minimum nitrogen oxide concentration ratio in the flue gas from all the nitrogen oxide concentration ratios in the flue gas; Calculating the difference between the maximum flue gas nitrogen oxide concentration ratio and the minimum flue gas nitrogen oxide concentration ratio; Calculate the second difference between each nitrogen oxide concentration ratio in the flue gas and the difference respectively; Calculate the second difference average of all second differences and calculate the second nitrogen oxide variation coefficient: Wherein, E2 is the second nitrogen oxide variation coefficient, m2 is the number of the second difference, g i is the ith second difference, t is the second difference average, X is the normalized second preset nitrogen oxide concentration, and ξ is the adjustment coefficient; A secondary correction is performed on the ammonia injection flow rate according to the first nitrogen oxide variation coefficient and the second nitrogen oxide variation coefficient.

10. An intelligent ammonia injection control method, characterized in that: include: Real-time collection of nitrogen oxide concentration, ammonia concentration, temperature, flue gas flow, flue gas temperature and flue gas pressure in the SCR device; Selecting an initial ammonia injection flow rate according to the flue gas flow rate in the SCR device and a preset ammonia injection rule; After injecting ammonia according to the initial ammonia injection flow rate, judging whether to correct the initial ammonia injection flow rate according to the current nitrogen oxide concentration in the SCR device and the ammonia concentration in the SCR device; judging whether to adjust the temperature in the SCR device according to the relationship between the temperature in the SCR device and the preset temperature range; The concentration of nitrogen oxides in the flue gas at the outlet is collected in real time, and it is determined whether the SCR device needs to be corrected and controlled again based on the collected real-time data.

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