A fast response denitration system

Abstract

The application relates to the technical field of flue gas denitration, in particular to a quick-response denitration system, which comprises a collection module, a urea supply module and a control module.The collection module comprises a NOx sensor, which is used for collecting the NOx content in a flue gas pipeline in real time; the urea supply module is arranged on the outer side of the flue gas pipeline and is used for configuring urea solution with a preset concentration according to the NOx content; the control module comprises a temperature sensor, which is used for acquiring the real-time temperature of a catalyst; the control module is used for sending start-stop instructions to the urea supply module according to the real-time temperature and spraying instructions to the urea supply module according to the NOx content; and the correction module is used for acquiring real-time operation state parameters of the urea supply module and generating correction instructions according to the real-time operation state parameters.The application solves the technical problem that the response speed is slow because the water inflow and the ammonia inflow need to be adjusted respectively and the adjusted urea solution is sprayed according to the setting.

Description

Technical Field

[0001] This application relates to the field of flue gas denitrification technology, and in particular to a fast-response denitrification system. Background Technology

[0002] SCR (Selective Catalytic Reduction) denitrification technology, sometimes also known as ammonia catalytic reduction denitrification, involves injecting ammonia or other suitable reducing agents into the flue gas upstream of the catalyst. The catalyst (an alkali metal such as iron, vanadium, chromium, cobalt, or molybdenum) converts NOx in the flue gas into nitrogen and water at a temperature of 200-450℃.

[0003] In existing technologies, the ammonia injection device in flue gas denitrification systems typically uses a high-temperature fan, a pyrolysis furnace, and an ammonia injection grid. To address potential changes during the denitrification process, the influent water flow and ammonia flow need to be adjusted separately. The ammonia is then injected into the urea solution according to the set parameters, resulting in a slow response speed. Summary of the Invention

[0004] To address the aforementioned technical problems, this application provides a rapid-response denitrification system, aiming to solve the technical problem of slow response speed caused by the need to adjust the influent flow rate and ammonia flow rate separately, and then spraying ammonia into the adjusted urea solution according to the set parameters.

[0005] In some embodiments of this application, a urea solution of a preset concentration is prepared according to the NOx content. The opening of the first valve and the second valve are set according to the preset concentration of the urea solution. It is determined whether the prepared urea solution is qualified. If it is qualified, the spraying command for the start and stop time of the urea supply module is set according to the real-time temperature of the catalyst. If it is not qualified, the opening of the first valve and the second valve are corrected, and the urea concentration is re-determined. Ammonia is injected until the urea solution concentration is qualified. The urea supply module replaces the three major components in the traditional technology—pyrolysis furnace, high-temperature fan and ammonia injection grid. Urea spray heads are set in the flue itself. The urea spray heads spray according to the start and stop time, spraying intensity and spraying duration. This solves the technical problem in the prior art that the denitrification system needs to adjust the influent water flow and ammonia flow separately, and the adjusted urea solution is sprayed with ammonia according to the settings, which has a slow response speed.

[0006] In some embodiments of this application, a fast-response denitrification system is provided, comprising:

[0007] The acquisition module includes a NOx sensor, which is used to acquire the NOx content in the flue gas duct in real time;

[0008] A urea supply module is installed on the outside of the flue gas duct. The urea supply module is used to prepare a urea solution of a preset concentration according to the NOx content.

[0009] The control module includes a temperature sensor, which is used to acquire the real-time temperature of the catalyst. The control module is used to send start / stop commands to the urea supply module based on the real-time temperature and to send spray commands to the urea supply module based on the NOx content.

[0010] The correction module is used to obtain the real-time operating status parameters of the urea supply module and generate correction instructions based on the real-time operating status parameters.

[0011] In some embodiments of this application, the urea supply module includes:

[0012] A urea solution chamber is used to prepare a urea solution of a preset concentration. One end of the urea solution chamber is connected to a water supply reservoir, and the other end of the urea solution chamber is connected to a urea supply reservoir. A first valve is provided at the connection between the water supply reservoir and the urea solution chamber, and a second valve is provided at the connection between the urea supply reservoir and the urea solution chamber.

[0013] A urea spray pipe is installed inside the flue. Urea spray heads are evenly arranged on the urea spray pipe. The urea spray heads are used to receive spraying instructions, which include spraying intensity and spraying duration.

[0014] In some embodiments of this application, a urea solution of a preset concentration is prepared according to the NOx content, including:

[0015] Obtain historical NOx content and corresponding historical urea solution, and construct a NOx content-urea solution mapping table based on historical NOx content and corresponding historical urea solution;

[0016] Based on the real-time collected NOx content, and using the NOx content-urea solution mapping table, a urea solution of a preset concentration is obtained.

[0017] Obtain the historical first valve opening and historical second valve opening corresponding to the historical urea solution, and construct a urea solution-valve opening self-adjustment model based on the historical first valve opening and historical second valve opening corresponding to the historical urea solution.

[0018] Input a urea solution of a preset concentration into the urea solution-valve opening self-adjustment model to determine the first valve opening and the second valve opening corresponding to the current urea solution.

[0019] The prepared urea solution is stirred for a preset time, and then it is determined whether the urea solution is qualified.

[0020] In some embodiments of this application, determining whether a urea solution is qualified includes:

[0021] The concentration of the urea solution was obtained multiple times, and the concentration was analyzed and processed. Abnormal concentration data were removed, and the remaining concentrations were subtracted from the preset concentrations to obtain the concentration difference values.

[0022] The average concentration difference is obtained based on multiple concentration differences. A first qualified evaluation value is generated based on the average concentration difference. A correction coefficient for the first qualified evaluation value is generated based on the number of abnormal concentration data removed. The first qualified evaluation value is corrected based on the correction coefficient.

[0023] Based on historical urea solutions and related factors during historical urea solution measurements, the measurement factors affecting urea solution density are determined. Characteristic variables are obtained based on these measurement factors, and a density prediction model is trained based on these characteristic variables.

[0024] Obtain the change curve of the historical data corresponding to the feature variable, extract the prediction curve of the preset time period from the change curve based on the real-time data corresponding to the feature variable, and input the data involved in the prediction curve into the density prediction model to obtain multiple predicted urea solution densities.

[0025] A second qualified evaluation value is generated based on the predicted fluctuation range of urea solution density within a preset time period;

[0026] A comprehensive evaluation value is generated based on the revised first and second qualification evaluation values.

[0027] The comprehensive evaluation value is:

[0028] K = H1 * e * a1 + H2 * a2;

[0029] Where K is the comprehensive evaluation value, e is the correction coefficient of the first qualified evaluation value, a1 is the weight coefficient corresponding to the first qualified evaluation value, H2 is the second qualified evaluation value, and a2 is the weight coefficient corresponding to the second qualified evaluation value.

[0030] If the comprehensive evaluation value is greater than the preset comprehensive evaluation value threshold, the urea solution is deemed qualified; if the comprehensive evaluation value is less than the preset comprehensive evaluation value threshold, the urea solution is deemed unqualified. The opening of the first valve and the opening of the second valve are corrected according to the solution concentration and the predicted density of the urea solution.

[0031] In some embodiments of this application, a first compliance value correction coefficient is generated based on the number of abnormal concentration data points removed, including:

[0032] The urea supply module is preset with a first preset number, a second preset number, a third preset number, and also preset with a first preset coefficient e1, a second preset coefficient e2, a third preset coefficient e3, and a fourth preset coefficient e4.

[0033] When the number of abnormal concentration data removed is less than the first preset number, the fourth preset coefficient e4 is selected as the first qualified evaluation value correction coefficient e, that is, e = e4;

[0034] When the number of abnormal concentration data removed is between the first preset number and the second preset number, the third preset coefficient e3 is selected as the first qualified evaluation value correction coefficient e, that is, e = e3;

[0035] When the number of abnormal concentration data removed is between the second preset number and the third preset number, the second preset coefficient e2 is selected as the first qualified evaluation value correction coefficient e, that is, e = e2;

[0036] When the number of abnormal concentration data removed is greater than the third preset number, the first preset coefficient e1 is selected as the first qualified evaluation value correction coefficient e, that is, e = e1.

[0037] In some embodiments of this application, sending start / stop commands to the urea supply module based on real-time temperature includes:

[0038] The real-time temperature of the catalyst is obtained, and the difference between the first preset temperature value and the real-time temperature is calculated to obtain the first temperature difference value. The opening time is set according to the relationship between the first temperature difference value and the preset first temperature difference value.

[0039] The control module is used to preset a first preset first temperature difference, a second preset first temperature difference, a third preset first temperature difference, and also preset a first preset opening time t01, a second preset opening time t02, a third preset opening time t03, and a fourth preset opening time t04.

[0040] When the first temperature difference is less than the first preset first temperature difference, the first preset opening time t01 is selected as the current opening time;

[0041] When the first temperature difference is between the first preset first temperature difference and the second preset first temperature difference, the second preset opening time t02 is selected as the current opening time.

[0042] When the first temperature difference is between the second preset first temperature difference and the third preset first temperature difference, the third preset opening time t03 is selected as the current opening time.

[0043] When the first temperature difference is greater than the third preset first temperature difference, the fourth preset opening time t04 is selected as the current opening time.

[0044] The real-time temperature change rate is obtained, and the first opening time is corrected by selecting the corresponding preset first time correction coefficient based on the ratio of the change rate to the preset change rate.

[0045] The control module is used to preset the first preset rate of change ratio interval, the second preset rate of change ratio interval, the third preset rate of change ratio interval and the fourth preset change amount ratio interval, and also preset the first preset first time correction coefficient s1, the second preset first time correction coefficient s2, the third preset first time correction coefficient s3 and the fourth preset first time correction coefficient s4.

[0046] When the rate of change ratio is within the first preset rate of change ratio range, the fourth preset first time correction coefficient s4 is selected to correct the i-th preset opening time, and the corrected opening time is s4*t0i.

[0047] When the rate of change ratio is within the second preset rate of change ratio range, the third preset first time correction coefficient s3 is selected to correct the i-th preset opening time. The corrected opening time is s3*t0i.

[0048] When the rate of change ratio is within the third preset rate of change ratio range, the second preset first time correction coefficient s2 is selected to correct the i-th preset opening time. The corrected opening time is s2*t0i.

[0049] When the rate of change ratio is within the fourth preset rate of change ratio range, the first preset first time correction coefficient s1 is selected to correct the i-th preset opening time, and the corrected opening time is s1*t0i.

[0050] In some embodiments of this application, sending start / stop commands to the urea supply module based on real-time temperature further includes:

[0051] The second preset temperature value is subtracted from the real-time temperature to obtain the second temperature difference value. The stop time is set according to the relationship between the second temperature difference value and the preset second temperature difference value.

[0052] The control module presets a first preset second temperature difference, a second preset second temperature difference, a third preset second temperature difference, and also presets a first preset stop time t1, a second preset stop time t2, a third preset stop time t3, and a fourth preset stop time t4.

[0053] When the second temperature difference is less than the first preset second temperature difference, the first preset stop time t1 is selected as the current stop time;

[0054] When the second temperature difference is between the first preset second temperature difference and the second preset second temperature difference, the second preset stop time t2 is selected as the current stop time.

[0055] When the second temperature difference is between the second preset second temperature difference and the third preset second temperature difference, the third preset stop time t3 is selected as the current stop time;

[0056] When the second temperature difference is greater than the third preset second temperature difference, the fourth preset stop time t4 is selected as the current stop time.

[0057] The rate of decrease of NOx content is obtained, and the stop time is corrected by selecting the corresponding preset second time correction coefficient based on the ratio of the rate of decrease to the preset rate of decrease.

[0058] The control module is used to preset the first preset descent rate ratio range, the second preset descent rate ratio range, the third preset descent rate ratio range and the fourth preset descent rate ratio range, and also preset the first preset second time correction coefficient g1, the second preset second time correction coefficient g2, the third preset second time correction coefficient g3 and the fourth preset second time correction coefficient g4.

[0059] When the descent rate ratio is within the first preset descent rate ratio range, the fourth preset second time correction coefficient g4 is selected to correct the i-th preset stop time. The corrected stop time is g4*ti.

[0060] When the descent rate ratio is within the second preset descent rate ratio range, the third preset second time correction coefficient g3 is selected to correct the i-th preset stop time. The corrected stop time is g3*ti.

[0061] When the descent rate ratio is within the third preset descent rate ratio range, the second preset second time correction coefficient g2 is selected to correct the i-th preset stop time. The corrected stop time is g2*ti.

[0062] When the descent rate ratio is within the fourth preset descent rate ratio range, the first preset second time correction coefficient g1 is selected to correct the i-th preset stop time, and the corrected stop time is g1*ti.

[0063] In some embodiments of this application, sending a spraying command to the urea supply module based on the NOx content includes:

[0064] A NOx content-spray intensity mapping table is constructed based on historical spraying data. Based on the NOx content-urea solution mapping table, the spray intensity corresponding to the current NOx content and the current urea solution is determined.

[0065] The real-time NOx content is obtained, and the spraying duration is set according to the relationship between the ratio of the real-time NOx content to the spraying intensity and the preset ratio range.

[0066] The control module is used to preset a first preset ratio range, a second preset ratio range, a third preset ratio range and a fourth preset ratio range, and also preset a first preset spraying duration, a second preset spraying duration, a third preset spraying duration and a fourth preset spraying duration.

[0067] When the ratio of real-time NOx content to spray intensity is within the first preset ratio range, the first preset spray duration is selected as the current spray duration.

[0068] When the ratio of real-time NOx content to spray intensity is within the second preset ratio range, the second preset spray duration is selected as the current spray duration.

[0069] When the ratio of real-time NOx content to spray intensity is within the third preset ratio range, the third preset spray duration is selected as the current spray duration.

[0070] When the ratio of real-time NOx content to spray intensity is within the fourth preset ratio range, the fourth preset spray duration is selected as the current spray duration.

[0071] In some embodiments of this application, generating correction instructions based on the real-time operating status parameters includes:

[0072] Obtain the actual solution concentration of urea solution, the start and stop time of urea supply module, and the actual spraying duration of urea spray head;

[0073] If the actual solution concentration is greater than the preset solution concentration threshold, a first-level correction instruction is generated.

[0074] If the start-stop time exceeds the preset start-stop time threshold, a secondary correction instruction is generated;

[0075] If the actual spraying time exceeds the preset spraying time threshold, a three-level correction instruction is generated.

[0076] The fast-response denitrification system of this application embodiment has the following advantages compared with the prior art:

[0077] A urea solution of a preset concentration is prepared based on the NOx content. The opening of the first and second valves is set according to the preset concentration of the urea solution. The prepared urea solution is judged to be qualified. If qualified, the spraying command for the start and stop time of the urea supply module is set according to the real-time temperature of the catalyst. If unqualified, the opening of the first and second valves is corrected, and the urea concentration is re-judged until the urea solution concentration is qualified, at which point ammonia is injected. The urea supply module replaces the three major components in the traditional technology—pyrolysis furnace, high-temperature fan, and ammonia injection grid. Urea spray heads are installed in the flue itself. The urea spray heads spray according to the start and stop time, spraying intensity, and spraying duration. This solves the technical problem in the existing denitrification system that requires separate adjustment of the influent water flow and ammonia flow, and the urea solution is sprayed with ammonia according to the settings, resulting in a slow response speed. Attached Figure Description

[0078] Figure 1 This is a schematic diagram of a fast-response denitrification system in a preferred embodiment of this application;

[0079] The components include: 1. Urea solution chamber; 2. Urea spray pipe; 3. Flue gas duct; 4. Water supply reservoir; 5. Urea supply reservoir; 6. First valve; 7. Second valve; 8. Catalyst; 9. NOx sensor; 10. Temperature sensor. Detailed Implementation

[0080] The specific embodiments of this application will be described in further detail below with reference to the accompanying drawings and examples. The following examples are used to illustrate this application, but are not intended to limit the scope of this application.

[0081] 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.

[0082] The terms "first" 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 as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, unless otherwise stated, "a plurality of" means two or more.

[0083] 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.

[0084] like Figure 1 As shown, a preferred embodiment of the present application provides a fast-response denitrification system, comprising:

[0085] The acquisition module includes a NOx sensor 9, which is used to acquire the NOx content in the flue gas duct 3 in real time.

[0086] A urea supply module is installed on the outside of the flue gas duct 3. The urea supply module is used to prepare a urea solution of a preset concentration according to the NOx content.

[0087] The control module includes a temperature sensor 10, which is used to acquire the real-time temperature of the catalyst 8. The control module is used to send start / stop commands to the urea supply module based on the real-time temperature and to send spray commands to the urea supply module based on the NOx content.

[0088] The correction module is used to obtain the real-time operating status parameters of the urea supply module and generate correction instructions based on the real-time operating status parameters.

[0089] In some embodiments of this application, the urea supply module includes:

[0090] The urea solution chamber 1 is used to prepare a urea solution of a preset concentration. One end of the urea solution chamber 1 is connected to the water supply tank 4, and the other end of the urea solution chamber 1 is connected to the urea supply tank 5. A first valve 6 is provided at the connection between the water supply tank 4 and the urea solution chamber 1, and a second valve 7 is provided at the connection between the urea supply tank 5 and the urea solution chamber 1.

[0091] A urea spray pipe 2 is installed inside the flue. Urea spray heads are evenly arranged on the urea spray pipe 2. The urea spray heads are used to receive spray instructions, which include spray intensity and spray duration.

[0092] In some embodiments of this application, a urea solution of a preset concentration is prepared according to the NOx content, including:

[0093] Obtain historical NOx content and corresponding historical urea solution, and construct a NOx content-urea solution mapping table based on historical NOx content and corresponding historical urea solution;

[0094] Based on the real-time collected NOx content, and using the NOx content-urea solution mapping table, a urea solution of a preset concentration is obtained.

[0095] Obtain the historical first valve opening and historical second valve opening corresponding to the historical urea solution, and construct a urea solution-valve opening self-adjustment model based on the historical first valve opening and historical second valve opening corresponding to the historical urea solution.

[0096] Input a urea solution of a preset concentration into the urea solution-valve opening self-adjustment model to determine the first valve opening and the second valve opening corresponding to the current urea solution.

[0097] The prepared urea solution is stirred for a preset time, and then it is determined whether the urea solution is qualified.

[0098] In some embodiments of this application, determining whether a urea solution is qualified includes:

[0099] The concentration of the urea solution was obtained multiple times, and the concentration was analyzed and processed. Abnormal concentration data were removed, and the remaining concentrations were subtracted from the preset concentrations to obtain the concentration difference values.

[0100] The average concentration difference is obtained based on multiple concentration differences. A first qualified evaluation value is generated based on the average concentration difference. A correction coefficient for the first qualified evaluation value is generated based on the number of abnormal concentration data removed. The first qualified evaluation value is corrected based on the correction coefficient.

[0101] Based on historical urea solutions and related factors during historical urea solution measurements, the measurement factors affecting urea solution density are determined. Characteristic variables are obtained based on these measurement factors, and a density prediction model is trained based on these characteristic variables.

[0102] Obtain the change curve of the historical data corresponding to the feature variable, extract the prediction curve of the preset time period from the change curve based on the real-time data corresponding to the feature variable, and input the data involved in the prediction curve into the density prediction model to obtain multiple predicted urea solution densities.

[0103] A second qualified evaluation value is generated based on the predicted fluctuation range of urea solution density within a preset time period;

[0104] A comprehensive evaluation value is generated based on the revised first and second qualification evaluation values.

[0105] The comprehensive evaluation value is:

[0106] K = H1 * e * a1 + H2 * a2;

[0107] Where K is the comprehensive evaluation value, e is the correction coefficient of the first qualified evaluation value, a1 is the weight coefficient corresponding to the first qualified evaluation value, H2 is the second qualified evaluation value, and a2 is the weight coefficient corresponding to the second qualified evaluation value.

[0108] If the comprehensive evaluation value is greater than the preset comprehensive evaluation value threshold, the urea solution is deemed qualified; if the comprehensive evaluation value is less than the preset comprehensive evaluation value threshold, the urea solution is deemed unqualified. The opening degree of the first valve 6 and the second valve 7 are corrected according to the solution concentration and predicted urea solution density.

[0109] In this embodiment, the measurement factors include solution level, instantaneous supply of urea in reservoir 5, and instantaneous water supply of water in reservoir 4. The characteristic variables are determined based on the correlation between the changes in the measurement factors and the density of the urea solution. The density prediction model is trained based on the characteristic variables and historical urea solution densities.

[0110] In some embodiments of this application, a first compliance value correction coefficient is generated based on the number of abnormal concentration data points removed, including:

[0111] The urea supply module is preset with a first preset number, a second preset number, a third preset number, and also preset with a first preset coefficient e1, a second preset coefficient e2, a third preset coefficient e3, and a fourth preset coefficient e4.

[0112] When the number of abnormal concentration data removed is less than the first preset number, the fourth preset coefficient e4 is selected as the first qualified evaluation value correction coefficient e, that is, e = e4;

[0113] When the number of abnormal concentration data removed is between the first preset number and the second preset number, the third preset coefficient e3 is selected as the first qualified evaluation value correction coefficient e, that is, e = e3;

[0114] When the number of abnormal concentration data removed is between the second preset number and the third preset number, the second preset coefficient e2 is selected as the first qualified evaluation value correction coefficient e, that is, e = e2;

[0115] When the number of abnormal concentration data removed is greater than the third preset number, the first preset coefficient e1 is selected as the first qualified evaluation value correction coefficient e, that is, e = e1.

[0116] In this embodiment, 0.5 < e1 < e2 < e3 < e4 < 1. Abnormal concentration data specifically refers to concentration data that differs significantly from the current solution concentration. The more abnormal concentration data are removed, the lower the accuracy of the current solution concentration, and therefore the smaller the first qualified evaluation value will be.

[0117] In some embodiments of this application, sending start / stop commands to the urea supply module based on real-time temperature includes:

[0118] The real-time temperature of catalyst 8 is obtained, and the difference between the first preset temperature value and the real-time temperature is calculated to obtain the first temperature difference value. The opening time is set according to the relationship between the first temperature difference value and the preset first temperature difference value.

[0119] The control module is used to preset a first preset first temperature difference, a second preset first temperature difference, a third preset first temperature difference, and also preset a first preset opening time t01, a second preset opening time t02, a third preset opening time t03, and a fourth preset opening time t04.

[0120] When the first temperature difference is less than the first preset first temperature difference, the first preset opening time t01 is selected as the current opening time;

[0121] When the first temperature difference is between the first preset first temperature difference and the second preset first temperature difference, the second preset opening time t02 is selected as the current opening time.

[0122] When the first temperature difference is between the second preset first temperature difference and the third preset first temperature difference, the third preset opening time t03 is selected as the current opening time.

[0123] When the first temperature difference is greater than the third preset first temperature difference, the fourth preset opening time t04 is selected as the current opening time.

[0124] The real-time temperature change rate is obtained, and the first opening time is corrected by selecting the corresponding preset first time correction coefficient based on the ratio of the change rate to the preset change rate.

[0125] The control module is used to preset the first preset rate of change ratio interval, the second preset rate of change ratio interval, the third preset rate of change ratio interval and the fourth preset change amount ratio interval, and also preset the first preset first time correction coefficient s1, the second preset first time correction coefficient s2, the third preset first time correction coefficient s3 and the fourth preset first time correction coefficient s4.

[0126] When the rate of change ratio is within the first preset rate of change ratio range, the fourth preset first time correction coefficient s4 is selected to correct the i-th preset opening time, and the corrected opening time is s4*t0i.

[0127] When the rate of change ratio is within the second preset rate of change ratio range, the third preset first time correction coefficient s3 is selected to correct the i-th preset opening time. The corrected opening time is s3*t0i.

[0128] When the rate of change ratio is within the third preset rate of change ratio range, the second preset first time correction coefficient s2 is selected to correct the i-th preset opening time. The corrected opening time is s2*t0i.

[0129] When the rate of change ratio is within the fourth preset rate of change ratio range, the first preset first time correction coefficient s1 is selected to correct the i-th preset opening time, and the corrected opening time is s1*t0i.

[0130] In this embodiment, the first preset rate of change ratio interval is (0.6, 0.8), the second preset rate of change ratio interval is (0.8, 1), the third preset rate of change ratio interval is (1, 1.2), and the fourth preset rate of change ratio interval is (1.2, 1.4), and 0.8 < s1 < s2 < 1 < s3 < s4 < 1.2, the first preset first temperature difference < the second preset first temperature difference < the third preset first temperature difference, and t01 < t02 < t03 < t04. For example, the first preset start time is ten minutes after the moment when the current temperature difference is obtained, and the second preset start time is twenty minutes after the moment when the current temperature difference is obtained.

[0131] In some embodiments of this application, sending start / stop commands to the urea supply module based on real-time temperature further includes:

[0132] The second preset temperature value is subtracted from the real-time temperature to obtain the second temperature difference value. The stop time is set according to the relationship between the second temperature difference value and the preset second temperature difference value.

[0133] The control module presets a first preset second temperature difference, a second preset second temperature difference, a third preset second temperature difference, and also presets a first preset stop time t1, a second preset stop time t2, a third preset stop time t3, and a fourth preset stop time t4.

[0134] When the second temperature difference is less than the first preset second temperature difference, the first preset stop time t1 is selected as the current stop time;

[0135] When the second temperature difference is between the first preset second temperature difference and the second preset second temperature difference, the second preset stop time t2 is selected as the current stop time.

[0136] When the second temperature difference is between the second preset second temperature difference and the third preset second temperature difference, the third preset stop time t3 is selected as the current stop time;

[0137] When the second temperature difference is greater than the third preset second temperature difference, the fourth preset stop time t4 is selected as the current stop time.

[0138] The rate of decrease of NOx content is obtained, and the stop time is corrected by selecting the corresponding preset second time correction coefficient based on the ratio of the rate of decrease to the preset rate of decrease.

[0139] The control module is used to preset the first preset descent rate ratio range, the second preset descent rate ratio range, the third preset descent rate ratio range and the fourth preset descent rate ratio range, and also preset the first preset second time correction coefficient g1, the second preset second time correction coefficient g2, the third preset second time correction coefficient g3 and the fourth preset second time correction coefficient g4.

[0140] When the descent rate ratio is within the first preset descent rate ratio range, the fourth preset second time correction coefficient g4 is selected to correct the i-th preset stop time. The corrected stop time is g4*ti.

[0141] When the descent rate ratio is within the second preset descent rate ratio range, the third preset second time correction coefficient g3 is selected to correct the i-th preset stop time. The corrected stop time is g3*ti.

[0142] When the descent rate ratio is within the third preset descent rate ratio range, the second preset second time correction coefficient g2 is selected to correct the i-th preset stop time. The corrected stop time is g2*ti.

[0143] When the descent rate ratio is within the fourth preset descent rate ratio range, the first preset second time correction coefficient g1 is selected to correct the i-th preset stop time, and the corrected stop time is g1*ti.

[0144] In this embodiment, the first preset rate of decrease ratio interval is (1, 1.1), the second preset rate of decrease ratio interval is (1.1, 1.2), the third preset rate of decrease ratio interval is (1.2, 1.3), and the fourth preset rate of decrease ratio interval is (1.3, 1.4), and 0.6 < g1 < g2 < g3 < g4 < 1, the first preset second temperature difference < the second preset second temperature difference < the third preset second temperature difference, and t1 < t2 < t3 < t4. For example, the first preset stop time is one hour after the moment when the current second temperature difference is obtained, and the second preset stop time is one and a half hours after the moment when the current second temperature difference is obtained. Both the preset stop time and the corrected stop time are less than the moment when the catalyst 8 temperature reaches 420°C.

[0145] In some embodiments of this application, sending a spraying command to the urea supply module based on the NOx content includes:

[0146] A NOx content-spray intensity mapping table is constructed based on historical spraying data. Based on the NOx content-urea solution mapping table, the spray intensity corresponding to the current NOx content and the current urea solution is determined.

[0147] The real-time NOx content is obtained, and the spraying duration is set according to the relationship between the ratio of the real-time NOx content to the spraying intensity and the preset ratio range.

[0148] The control module is used to preset a first preset ratio range, a second preset ratio range, a third preset ratio range and a fourth preset ratio range, and also preset a first preset spraying duration, a second preset spraying duration, a third preset spraying duration and a fourth preset spraying duration.

[0149] When the ratio of real-time NOx content to spray intensity is within the first preset ratio range, the first preset spray duration is selected as the current spray duration.

[0150] When the ratio of real-time NOx content to spray intensity is within the second preset ratio range, the second preset spray duration is selected as the current spray duration.

[0151] When the ratio of real-time NOx content to spray intensity is within the third preset ratio range, the third preset spray duration is selected as the current spray duration.

[0152] When the ratio of real-time NOx content to spray intensity is within the fourth preset ratio range, the fourth preset spray duration is selected as the current spray duration.

[0153] In some embodiments of this application, generating correction instructions based on the real-time operating status parameters includes:

[0154] Obtain the actual solution concentration of urea solution, the start and stop time of urea supply module, and the actual spraying duration of urea spray head;

[0155] If the actual solution concentration is greater than the preset solution concentration threshold, a first-level correction instruction is generated.

[0156] If the start-stop time exceeds the preset start-stop time threshold, a secondary correction instruction is generated;

[0157] If the actual spraying time exceeds the preset spraying time threshold, a three-level correction instruction is generated.

[0158] In this embodiment, the first-level correction instruction is to correct the opening degree of the first valve 6 and the second valve 7, the second-level correction instruction is to correct the preset opening time and preset stopping time, and the third-level correction instruction is to correct the preset spraying duration.

[0159] According to the first concept of this application, a urea solution of a preset concentration is prepared based on the NOx content. The opening of the first valve 6 and the second valve 7 are set according to the preset concentration of the urea solution. It is determined whether the prepared urea solution is qualified. If it is qualified, the spraying command for the start and stop time of the urea supply module is set according to the real-time temperature of the catalyst 8. If it is not qualified, the opening of the first valve 6 and the second valve 7 are corrected, and the urea concentration is re-determined until the urea solution concentration is qualified, and then ammonia is injected. The urea supply module replaces the three major components in the traditional technology - pyrolysis furnace, high-temperature fan and ammonia injection grid. Urea spray heads are set in the flue itself. The urea spray heads spray according to the start and stop time, spraying intensity and spraying duration. This solves the technical problem in the prior art that the denitrification system needs to adjust the influent water flow and ammonia flow separately, and the adjusted urea solution is sprayed with ammonia according to the settings, which has a slow response speed.

[0160] The above description is only a preferred embodiment of this application. It should be noted that for those skilled in the art, several improvements and substitutions can be made without departing from the technical principles of this application, and these improvements and substitutions should also be considered within the scope of protection of this application.

Claims

1. A fast-response denitrification system, characterized in that, include: The acquisition module includes a NOx sensor, which is used to acquire the NOx content in the flue gas duct in real time; A urea supply module is installed on the outside of the flue gas duct. The urea supply module is used to prepare a urea solution of a preset concentration according to the NOx content. The control module includes a temperature sensor, which is used to acquire the real-time temperature of the catalyst. The control module is used to send start / stop commands to the urea supply module based on the real-time temperature and to send spray commands to the urea supply module based on the NOx content. The correction module is used to obtain the real-time operating status parameters of the urea supply module and generate correction instructions based on the real-time operating status parameters. Determining whether a urea solution is up to standard includes: The concentration of the urea solution was obtained multiple times, and the concentration was analyzed and processed. Abnormal concentration data were removed, and the remaining concentrations were subtracted from the preset concentrations to obtain the concentration difference values. The average concentration difference is obtained based on multiple concentration differences. A first qualified evaluation value is generated based on the average concentration difference. A correction coefficient for the first qualified evaluation value is generated based on the number of abnormal concentration data removed. The first qualified evaluation value is corrected based on the correction coefficient. Based on historical urea solutions and related factors during historical urea solution measurements, the measurement factors affecting urea solution density are determined. Characteristic variables are obtained based on these measurement factors, and a density prediction model is trained based on these characteristic variables. Obtain the change curve of the historical data corresponding to the feature variable, extract the prediction curve of the preset time period from the change curve based on the real-time data corresponding to the feature variable, and input the data involved in the prediction curve into the density prediction model to obtain multiple predicted urea solution densities. A second qualified evaluation value is generated based on the predicted fluctuation range of urea solution density within a preset time period; A comprehensive evaluation value is generated based on the revised first and second qualification evaluation values. The comprehensive evaluation value is: K=H1 e a1+H2 a2; Where K is the comprehensive evaluation value, e is the correction coefficient of the first qualified evaluation value, a1 is the weight coefficient corresponding to the first qualified evaluation value, H2 is the second qualified evaluation value, and a2 is the weight coefficient corresponding to the second qualified evaluation value. If the comprehensive evaluation value is greater than the preset comprehensive evaluation value threshold, the urea solution is deemed qualified; if the comprehensive evaluation value is less than the preset comprehensive evaluation value threshold, the urea solution is deemed unqualified. The opening of the first valve and the opening of the second valve are corrected according to the solution concentration and the predicted density of the urea solution.

2. The rapid-response denitrification system as described in claim 1, characterized in that, The urea supply module includes: A urea solution chamber is used to prepare a urea solution of a preset concentration. One end of the urea solution chamber is connected to a water supply reservoir, and the other end of the urea solution chamber is connected to a urea supply reservoir. A first valve is provided at the connection between the water supply reservoir and the urea solution chamber, and a second valve is provided at the connection between the urea supply reservoir and the urea solution chamber. A urea spray pipe is installed inside the flue. Urea spray heads are evenly arranged on the urea spray pipe. The urea spray heads are used to receive spraying instructions, which include spraying intensity and spraying duration.

3. The rapid-response denitrification system as described in claim 2, characterized in that, Prepare a urea solution of a preset concentration according to the NOx content, including: Obtain historical NOx content and corresponding historical urea solution, and construct a NOx content-urea solution mapping table based on historical NOx content and corresponding historical urea solution; Based on the real-time collected NOx content, and using the NOx content-urea solution mapping table, a urea solution of a preset concentration is obtained. Obtain the historical first valve opening and historical second valve opening corresponding to the historical urea solution, and construct a urea solution-valve opening self-adjustment model based on the historical first valve opening and historical second valve opening corresponding to the historical urea solution. Input a urea solution of a preset concentration into the urea solution-valve opening self-adjustment model to determine the first valve opening and the second valve opening corresponding to the current urea solution. The prepared urea solution is stirred for a preset time, and then it is determined whether the urea solution is qualified.

4. The rapid-response denitrification system as described in claim 3, characterized in that, The correction coefficient for the first compliance evaluation value is generated based on the number of abnormal concentration data removed, including: The urea supply module is preset with a first preset number, a second preset number, a third preset number, and also preset with a first preset coefficient e1, a second preset coefficient e2, a third preset coefficient e3, and a fourth preset coefficient e4. When the number of abnormal concentration data removed is less than the first preset number, the fourth preset coefficient e4 is selected as the first qualified evaluation value correction coefficient e, that is, e=e4; When the number of abnormal concentration data removed is between the first preset number and the second preset number, the third preset coefficient e3 is selected as the first qualified evaluation value correction coefficient e, that is, e=e3; When the number of abnormal concentration data removed is between the second preset number and the third preset number, the second preset coefficient e2 is selected as the first qualified evaluation value correction coefficient e, that is, e=e2; When the number of abnormal concentration data removed is greater than the third preset number, the first preset coefficient e1 is selected as the first qualified evaluation value correction coefficient e, that is, e=e1.

5. The rapid-response denitrification system as described in claim 2, characterized in that, Send start / stop commands to the urea supply module based on real-time temperature, including: The real-time temperature of the catalyst is obtained, and the difference between the first preset temperature value and the real-time temperature is calculated to obtain the first temperature difference value. The opening time is set according to the relationship between the first temperature difference value and the preset first temperature difference value. The control module is used to preset a first preset first temperature difference, a second preset first temperature difference, a third preset first temperature difference, and also preset a first preset opening time t01, a second preset opening time t02, a third preset opening time t03, and a fourth preset opening time t04. When the first temperature difference is less than the first preset first temperature difference, the first preset opening time t01 is selected as the current opening time; When the first temperature difference is between the first preset first temperature difference and the second preset first temperature difference, the second preset opening time t02 is selected as the current opening time. When the first temperature difference is between the second preset first temperature difference and the third preset first temperature difference, the third preset opening time t03 is selected as the current opening time. When the first temperature difference is greater than the third preset first temperature difference, the fourth preset opening time t04 is selected as the current opening time. The real-time temperature change rate is obtained, and the opening time is corrected by selecting the corresponding preset first-time correction coefficient based on the ratio of the change rate to the preset change rate. The control module is used to preset the first preset rate of change ratio interval, the second preset rate of change ratio interval, the third preset rate of change ratio interval and the fourth preset change amount ratio interval, and also preset the first preset first time correction coefficient s1, the second preset first time correction coefficient s2, the third preset first time correction coefficient s3 and the fourth preset first time correction coefficient s4. When the rate of change ratio is within the first preset rate of change ratio range, the fourth preset first time correction coefficient s4 is selected to correct the i-th preset opening time, and the corrected opening time is s4. t0i; When the rate of change ratio is within the second preset rate of change ratio range, the third preset first time correction coefficient s3 is selected to correct the i-th preset opening time, and the corrected opening time is s3. t0i; When the rate of change ratio is within the third preset rate of change ratio range, the second preset first time correction coefficient s2 is selected to correct the i-th preset opening time, and the corrected opening time is s2. t0i; When the rate of change ratio is within the fourth preset rate of change ratio range, the first preset first time correction coefficient s1 is selected to correct the i-th preset opening time, and the corrected opening time is s1. t0i.

6. The rapid-response denitrification system as described in claim 5, characterized in that, Sending start / stop commands to the urea supply module based on real-time temperature also includes: The second preset temperature value is subtracted from the real-time temperature to obtain the second temperature difference value. The stop time is set according to the relationship between the second temperature difference value and the preset second temperature difference value. The control module presets a first preset second temperature difference, a second preset second temperature difference, a third preset second temperature difference, and also presets a first preset stop time t1, a second preset stop time t2, a third preset stop time t3, and a fourth preset stop time t4. When the second temperature difference is less than the first preset second temperature difference, the first preset stop time t1 is selected as the current stop time; When the second temperature difference is between the first preset second temperature difference and the second preset second temperature difference, the second preset stop time t2 is selected as the current stop time. When the second temperature difference is between the second preset second temperature difference and the third preset second temperature difference, the third preset stop time t3 is selected as the current stop time; When the second temperature difference is greater than the third preset second temperature difference, the fourth preset stop time t4 is selected as the current stop time. The rate of decrease of NOx content is obtained, and the stop time is corrected by selecting the corresponding preset second time correction coefficient based on the ratio of the rate of decrease to the preset rate of decrease. The control module is used to preset the first preset descent rate ratio range, the second preset descent rate ratio range, the third preset descent rate ratio range and the fourth preset descent rate ratio range, and also preset the first preset second time correction coefficient g1, the second preset second time correction coefficient g2, the third preset second time correction coefficient g3 and the fourth preset second time correction coefficient g4. When the descent rate ratio is within the first preset descent rate ratio range, the fourth preset second time correction coefficient g4 is selected to correct the i-th preset stop time, and the corrected stop time is g4. ti; When the descent rate ratio is within the second preset descent rate ratio range, the third preset second time correction coefficient g3 is selected to correct the i-th preset stop time, and the corrected stop time is g3. ti; When the descent rate ratio is within the third preset descent rate ratio range, the second preset time correction coefficient g2 is selected to correct the i-th preset stop time, and the corrected stop time is g2. ti; When the descent rate ratio is within the fourth preset descent rate ratio range, the first preset second time correction coefficient g1 is selected to correct the i-th preset stop time, and the corrected stop time is g1. ti.

7. The fast-response denitrification system as described in claim 6, characterized in that, Based on the NOx content, a spraying command is sent to the urea supply module, including: A NOx content-spray intensity mapping table is constructed based on historical spraying data. Based on the NOx content-urea solution mapping table, the spray intensity corresponding to the current NOx content and the current urea solution is determined. The real-time NOx content is obtained, and the spraying duration is set according to the relationship between the ratio of the real-time NOx content to the spraying intensity and the preset ratio range. The control module is used to preset a first preset ratio range, a second preset ratio range, a third preset ratio range and a fourth preset ratio range, and also preset a first preset spraying duration, a second preset spraying duration, a third preset spraying duration and a fourth preset spraying duration. When the ratio of real-time NOx content to spray intensity is within the first preset ratio range, the first preset spray duration is selected as the current spray duration. When the ratio of real-time NOx content to spray intensity is within the second preset ratio range, the second preset spray duration is selected as the current spray duration. When the ratio of real-time NOx content to spray intensity is within the third preset ratio range, the third preset spray duration is selected as the current spray duration. When the ratio of real-time NOx content to spray intensity is within the fourth preset ratio range, the fourth preset spray duration is selected as the current spray duration.

8. The fast-response denitrification system as described in claim 7, characterized in that, Generate correction instructions based on the real-time operating status parameters, including: Obtain the actual solution concentration of urea solution, the start and stop time of urea supply module, and the actual spraying duration of urea spray head; If the actual solution concentration is greater than the preset solution concentration threshold, a first-level correction instruction is generated. If the start-stop time exceeds the preset start-stop time threshold, a secondary correction instruction is generated; If the actual spraying time exceeds the preset spraying time threshold, a level 3 correction instruction is generated. The first-level correction command corrects the opening degree of the first valve and the second valve; the second-level correction command corrects the preset opening time and preset stopping time; and the third-level correction command corrects the preset spraying duration.

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