Ammonia spraying control system based on SCR flue gas denitration

Abstract

The invention discloses an ammonia spraying control system based on SCR (Selective Catalytic Reduction) flue gas denitration, which comprises an SCR reactor and a flow detection sensor for detecting the data of the amount of flue gas entering the SCR reactor; the first NOx concentration detection sensor is used for detecting NOx concentration data in inlet smoke; the second NOx concentration detection sensor is used for detecting concentration data of NOx in exhausted smoke; the ammonia escape amount detection sensor is used for detecting ammonia escape amount data of the flue; the ammonia spraying device is used for spraying ammonia gas into the SCR reactor; and the control unit is used for setting, correcting and adjusting the working conditions of the ammonia spraying device according to the detected data. The control unit is arranged on the SCR reactor, the initial working condition of the ammonia spraying device is set according to the detected data, and the initial working condition is corrected and adjusted in time according to the subsequently detected data, so that the economical efficiency is ensured while the SCR flue gas denitration efficiency is improved.

Description

Technical Field

[0001] The invention relates to the technical field of flue gas denitrification, and in particular to an ammonia injection control system based on SCR flue gas denitrification. Background Art

[0002] Since the flue gas discharged from the combustion system contains a large amount of nitrogen oxides, which are one of the main air pollutants, and more than 90% of them are NO, which is also difficult to dissolve in water, the wet treatment of NOx cannot be done by simple methods. SCR (Selective Catalytic Reduction) technology is the most mature and widely used flue gas denitrification technology in the world. Its principle is to spray ammonia or other nitrogen compounds into the tail gas containing nitrogen oxides, and under the action of the catalyst, the nitrogen oxides therein are reduced to nitrogen and water. Under the condition of a constant reaction temperature, the amount of ammonia used has a great influence on the denitrification efficiency of the SCR process. Selecting the appropriate amount of ammonia can greatly improve the denitrification effect of the SCR process. Therefore, in order to improve the denitrification efficiency of the SCR process, it is necessary to accurately control the amount of ammonia sprayed. Summary of the invention

[0003] In order to solve the above technical problems, the present invention provides an ammonia injection control system based on SCR flue gas denitrification, comprising:

[0004] An SCR reactor connected to the combustion furnace;

[0005] A flow detection sensor is arranged in the smoke inlet duct of the SCR reactor, and is used to detect the amount of smoke entering the SCR reactor;

[0006] A first NOx concentration detection sensor is arranged in the smoke inlet duct of the SCR reactor, and the first NOx concentration detection sensor is used to detect NOx concentration data in the smoke inlet;

[0007] A second NOx concentration detection sensor is disposed in the smoke outlet of the SCR reactor, and the second NOx concentration detection sensor is used to detect NOx concentration data in the exhaust smoke;

[0008] an ammonia escape amount detection sensor, arranged in the flue gas duct of the SCR reactor, and used to detect the ammonia escape amount data of the flue gas duct;

[0009] an ammonia spraying device, arranged in the flue gas inlet of the SCR reactor, and used for spraying ammonia gas into the SCR reactor;

[0010] The control unit is electrically connected to the flow detection sensor, the first NOx concentration detection sensor, the second NOx concentration detection sensor, the ammonia slip detection sensor, and the ammonia injection device, respectively. The control unit is used to set, correct and adjust the working conditions of the ammonia injection device according to the detected data.

[0011] Furthermore, the control unit comprises:

[0012] A collection module, respectively connected to the flow detection sensor, the first NOx concentration detection sensor, the second NOx concentration detection sensor, and the ammonia escape detection sensor, the collection module is used to collect data parameters of the flow detection sensor, the first NOx concentration detection sensor, the second NOx concentration detection sensor, and the ammonia escape detection sensor, and transmit the data parameters to the processing module;

[0013] A processing module connected to the acquisition module, the processing module is used to set a working state instruction of the ammonia injection device according to the data parameters;

[0014] A control module is connected to the processing module and to the ammonia injection device, and the control module is used to control the ammonia injection device according to the working state instruction set by the processing module.

[0015] Further, the acquisition module is used to acquire the smoke intake volume ΔG detected by the flow detection sensor, and the control module is used to control the ammonia spraying device;

[0016] The processing module is used to set the preset smoke intake value G0, and the processing module is also used to set the first preset smoke intake difference g1, the second preset smoke intake difference g2, the third preset smoke intake difference g3 and the fourth preset smoke intake difference g4, and g1<g2<g3<g4; the processing module is also used to set the first preset working condition matrix A1 (a1, b1), the second preset working condition matrix A2 (a2, b2), the third preset working condition matrix A3 (a3, b3) and the fourth preset working condition matrix A4 (a4, b4), wherein a1-a4 are the first ammonia injection device rod to the fourth preset ammonia injection flow rate, and a1<a2<a3<a4, b1-b4 are the first ammonia injection device rod to the fourth preset ammonia injection time, and b1<b2<b3<b4;

[0017] According to the difference between the smoke intake volume △G detected by the flow detection sensor and the preset value G0 of the smoke intake volume detected by the set flow detection sensor, a preset working condition matrix A is selected as the working condition of the ammonia spraying device;

[0018] When △G-G0≤g1, the first preset working condition matrix A1 is selected as the working condition of the ammonia injection device;

[0019] When g1<△G-G0≤g2, the second preset working condition matrix A2 is selected as the working condition of the ammonia injection device;

[0020] When g2<△G-G0≤g3, the third preset working condition matrix A3 is selected as the working condition of the ammonia injection device;

[0021] When g3<△G-G0≤g4, the fourth preset working condition matrix A4 is selected as the working condition of the ammonia injection device;

[0022] Among them, when the i-th preset working condition matrix Ai is selected as the working condition of the ammonia injection device, the control module controls the ammonia injection device to operate at the i-th preset ammonia injection flow rate ai, and the control module will also control the ammonia injection device to operate at the i-th preset ammonia injection duration bi, i=1, 2, 3, 4.

[0023] Further, the processing module is used to determine whether to adjust the working condition matrix Ai of the ammonia injection device according to the denitration efficiency of the SCR reactor;

[0024] If the calculated denitration efficiency of the SCR reactor meets the standard, there is no need to adjust the working condition matrix Ai of the ammonia injection device;

[0025] If the calculated denitration efficiency of the SCR reactor does not meet the standard, the working condition matrix Ai of the ammonia injection device needs to be adjusted.

[0026] Furthermore, the processing module is used to calculate the denitrification efficiency of the SCR reactor based on the data detected by the first NOx concentration detection sensor and the second NOx concentration detection sensor collected by the collection module, and the formula n=1-(m1÷m2)×100% is used to calculate the denitrification efficiency of the SCR reactor, wherein n is the denitrification efficiency, m1 is the concentration of NOx in the exhaust smoke detected by the second NOx concentration detection sensor, and m2 is the concentration of NOx in the intake smoke detected by the first NOx concentration detection sensor.

[0027] Furthermore, if the calculated denitration efficiency of the SCR reactor does not meet the standard, the working condition matrix Ai of the ammonia injection device needs to be adjusted, including:

[0028] The processing module is used to obtain the working condition matrix Ai (ai, bi) of the ammonia injection device, i = 1, 2, 3, 4;

[0029] The processing module is further used to obtain a denitration efficiency value d0 of the SCR reactor, and the processing module is used to pre-set a first preset denitration efficiency value d1, a second preset denitration efficiency value d2, a third preset denitration efficiency value d3, and a fourth preset denitration efficiency value d4, and d1<d2<d3<d4; the processing module is also used to pre-set a first preset adjustment coefficient x1, a second preset adjustment coefficient x2, a third preset adjustment coefficient x3, and a fourth preset adjustment coefficient x4, and 1>x1>x2>x3>x4>0.5;

[0030] The processing module is also used to adjust the working condition matrix Ai (ai, bi) of the ammonia injection device according to the relationship between the obtained denitration efficiency value of the SCR reactor and each preset denitration efficiency value:

[0031] When d0≤d1, the working condition matrix Ai of the ammonia injection device is not adjusted;

[0032] When d1<d0≤d2, the first preset adjustment coefficient x1 is selected to adjust the working condition matrix Ai of the ammonia injection device, and the adjusted working condition matrix is ​​Ai(ai*x1,bi*x1);

[0033] When d2<d0≤d3, the second preset adjustment coefficient x2 is selected to adjust the working condition matrix Ai of the ammonia injection device, and the adjusted working condition matrix is ​​Ai(ai*x2,bi*x2);

[0034] When d3<d0≤d4, the third preset adjustment coefficient x3 is selected to adjust the working condition matrix Ai of the ammonia injection device, and the adjusted working condition matrix is ​​Ai(ai*x3,bi*x3);

[0035] When d4<d0, the fourth preset adjustment coefficient x4 is selected to adjust the working condition matrix Ai of the ammonia injection device, and the adjusted working condition matrix is ​​Ai(ai*x4,bi*x4).

[0036] Furthermore, the acquisition module is used to obtain the ammonia slip amount detected by the current ammonia slip amount detection sensor, and the processing module is used to correct the adjusted working condition matrix Ai (ai*xi, bi*xi) of the ammonia injection device according to the ammonia slip amount, wherein:

[0037] Obtain denitrification efficiency and ammonia escape amount, and perform normalization processing on the denitrification efficiency and ammonia escape amount respectively;

[0038] Obtain target ratio data, and determine the target ratio of denitrification efficiency and ammonia escape amount after normalization according to the target ratio data;

[0039] Determine the target ammonia slip amount according to the target ratio of the denitration efficiency and the ammonia slip amount after normalization and the current denitration efficiency, and calculate the difference c0 between the current ammonia slip amount and the target ammonia slip amount;

[0040] A first preset difference c1, a second preset difference c2, a third preset difference c3 and a fourth preset difference c4 are preset, and c1<c2<c3<c4; a first preset correction coefficient y1, a second preset correction coefficient y2, a third preset correction coefficient y3 and a fourth preset correction coefficient y4 are preset, and 1>y1>y2>y3>y4>0.7;

[0041] The processing module is also used to modify the adjusted working condition matrix Ai (ai*xi, bi*xi) of the ammonia injection device according to the relationship between the difference c0 between the current ammonia slip amount and the target ammonia slip amount and each preset difference;

[0042] When c0≤c1, the working condition matrix Ai(ai*xi,bi*xi) of the ammonia injection device is not corrected;

[0043] When c1<c0≤c2, the first preset correction coefficient y1 is selected to correct the working condition matrix Ai(ai*xi, bi*xi) of the ammonia injection device, and the corrected working condition matrix is ​​Ai(ai*xi*y1, bi*xi*y1);

[0044] When c2<c0≤c3, the second preset correction coefficient y2 is selected to correct the working condition matrix Ai(ai*xi, bi*xi) of the ammonia injection device, and the corrected working condition matrix is ​​Ai(ai*xi*y2, ai*xi*y2);

[0045] When c3<c0≤c4, the third preset correction coefficient y3 is selected to correct the working condition matrix Ai(ai*xi, bi*xi) of the ammonia injection device, and the corrected working condition matrix is ​​Ai(ai*xi*y3, ai*xi*y3);

[0046] When c4<ci, the fourth preset correction coefficient y4 is selected to correct the working condition matrix Ai(ai*xi, bi*xi) of the ammonia injection device, and the corrected working condition matrix is ​​Ai(ai*xi*y4, ai*xi*y4).

[0047] Compared with the prior art, the ammonia injection control system based on SCR flue gas denitrification in the embodiment of the present invention has the following beneficial effects:

[0048] In the present invention, a control unit is arranged on the SCR reactor, and the initial working conditions of the ammonia injection device are set according to the detected data, and the initial working conditions are timely corrected and adjusted according to the subsequently detected data, so that the ammonia injection device can select a precise amount of ammonia injection to denitrate the flue gas, thereby improving the denitration efficiency of the SCR flue gas and ensuring economy. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] Figure 1 Schematic diagram of the composition of an ammonia injection control system based on SCR flue gas denitrification in an embodiment of the present invention;

[0050] Figure 2 Schematic diagram of the composition of a control unit of an ammonia injection control system based on SCR flue gas denitrification in an embodiment of the present invention;

[0051] Figure 3 It is a schematic diagram of electrical connections of a control unit of an ammonia injection control system based on SCR flue gas denitrification in an embodiment of the present invention. DETAILED DESCRIPTION

[0052] The specific implementation methods of the present application are 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.

[0053] 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.

[0054] 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.

[0055] 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.

[0056] like Figure 1 As shown, in an embodiment of the present application, an ammonia injection control system based on SCR flue gas denitrification is provided, comprising: an SCR reactor connected to the combustion furnace; a flow detection sensor arranged in the smoke inlet duct of the SCR reactor, the flow detection sensor being used to detect the smoke volume data entering the SCR reactor; a first NOx concentration detection sensor arranged in the smoke inlet duct of the SCR reactor, the first NOx concentration detection sensor being used to detect the NOx concentration data in the smoke inlet; a second NOx concentration detection sensor arranged in the smoke outlet duct of the SCR reactor, the second NOx concentration detection sensor being used to detect the NOx concentration data in the smoke inlet Used to detect NOX concentration data in exhaust smoke; an ammonia escape detection sensor, arranged in the smoke outlet duct of the SCR reactor, and the ammonia escape detection sensor is used to detect the ammonia escape data of the smoke outlet duct; an ammonia spraying device, arranged in the smoke inlet duct of the SCR reactor, and the ammonia spraying device is used to spray ammonia into the SCR reactor; a control unit, electrically connected to the flow detection sensor, the first NOX concentration detection sensor, the second NOX concentration detection sensor, the ammonia escape detection sensor, and the ammonia spraying device, respectively, and the control unit is used to set, correct and adjust the working conditions of the ammonia spraying device according to the detected data.

[0057] In an embodiment of the present application, the control unit includes: an acquisition module, which is respectively connected to the flow detection sensor, the first NOx concentration detection sensor, the second NOx concentration detection sensor, and the ammonia escape detection sensor, and the acquisition module is used to collect data parameters of the flow detection sensor, the first NOx concentration detection sensor, the second NOx concentration detection sensor, and the ammonia escape detection sensor, and transmit the data parameters to the processing module; a processing module, which is connected to the acquisition module, and the processing module is used to set the working state instruction of the ammonia injection device according to the data parameters; a control module, which is connected to the processing module and to the ammonia injection device, and the control module is used to control the ammonia injection device according to the working state instruction set by the processing module.

[0058] In an embodiment of the present application, the acquisition module is used to acquire the smoke intake volume ΔG detected by the flow detection sensor, and the control module is used to control the ammonia spraying device;

[0059] The processing module is used to set the preset smoke intake value G0, and the processing module is also used to set the first preset smoke intake difference G1, the second preset smoke intake difference G2, the third preset smoke intake difference G3 and the fourth preset smoke intake difference G4, and G1<G2<G3<G4; the processing module is also used to set the first preset working condition matrix A1 (A1, B1), the second preset working condition matrix A2 (A2, B2), the third preset working condition matrix A3 (A3, B3) and the fourth preset working condition matrix A4 (A4, B4), wherein A1-A4 are respectively the first ammonia injection device rod to the fourth preset ammonia injection flow rate, and A1<A2<A3<A4, B1-B4 are respectively the first ammonia injection device rod to the fourth preset ammonia injection time, and B1<B2<B3<B4;

[0060] According to the difference between the smoke intake volume △G detected by the flow detection sensor and the preset value G0 of the smoke intake volume detected by the set flow detection sensor, a preset working condition matrix A is selected as the working condition of the ammonia spraying device;

[0061] When △G-G0≤G1, the first preset working condition matrix A1 is selected as the working condition of the ammonia injection device;

[0062] When G1<△G-G0≤G2, the second preset working condition matrix A2 is selected as the working condition of the ammonia injection device;

[0063] When G2<△G-G0≤G3, the third preset working condition matrix A3 is selected as the working condition of the ammonia injection device;

[0064] When G3<△G-G0≤G4, the fourth preset working condition matrix A4 is selected as the working condition of the ammonia injection device;

[0065] Among them, when the first preset working condition matrix AI is selected as the working condition of the ammonia injection device, the control module controls the ammonia injection device to operate at the first preset ammonia injection flow rate AI, and the control module will also control the ammonia injection device to operate at the first preset ammonia injection duration BI, I = 1, 2, 3, 4.

[0066] In an embodiment of the present application, the processing module is used to determine whether to adjust the working condition matrix AI of the ammonia injection device according to the denitrification efficiency of the SCR reactor; if the calculated denitrification efficiency of the SCR reactor meets the standard, there is no need to adjust the working condition matrix AI of the ammonia injection device; if the calculated denitrification efficiency of the SCR reactor does not meet the standard, it is necessary to adjust the working condition matrix AI of the ammonia injection device.

[0067] In an embodiment of the present application, the processing module is used to calculate the denitrification efficiency of the SCR reactor based on the data detected by the first NOx concentration detection sensor and the second NOx concentration detection sensor collected by the acquisition module, and the formula N=1-(M1÷M2)×100% is used to calculate the denitrification efficiency of the SCR reactor, wherein N is the denitrification efficiency, M1 is the concentration of NOx in the exhaust smoke detected by the second NOx concentration detection sensor, and M2 is the concentration of NOx in the intake smoke detected by the first NOx concentration detection sensor.

[0068] In an embodiment of the present application, if the calculated denitration efficiency of the SCR reactor does not meet the standard, it is necessary to adjust the working condition matrix AI of the ammonia injection device, including:

[0069] The processing module is used to obtain the working condition matrix AI (AI, BI) of the ammonia injection device, where I = 1, 2, 3, 4;

[0070] The processing module is further used to obtain the denitration efficiency value D0 of the SCR reactor, and the processing module is used to pre-set a first preset denitration efficiency value D1, a second preset denitration efficiency value D2, a third preset denitration efficiency value D3 and a fourth preset denitration efficiency value D4, and D1<D2<D3<D4; the processing module is also used to pre-set a first preset adjustment coefficient X1, a second preset adjustment coefficient X2, a third preset adjustment coefficient X3 and a fourth preset adjustment coefficient X4, and 1>X1>X2>X3>X4>0.5;

[0071] The processing module is also used to adjust the working condition matrix AI (AI, BI) of the ammonia injection device according to the relationship between the obtained denitration efficiency value of the SCR reactor and each preset denitration efficiency value:

[0072] When D0≤D1, the working condition matrix AI of the ammonia injection device is not adjusted;

[0073] When D1<D0≤D2, the first preset adjustment coefficient X1 is selected to adjust the working condition matrix AI of the ammonia injection device, and the adjusted working condition matrix is ​​AI(AI*X1, BI*X1);

[0074] When D2<D0≤D3, the second preset adjustment coefficient X2 is selected to adjust the working condition matrix AI of the ammonia injection device, and the adjusted working condition matrix is ​​AI(AI*X2, BI*X2);

[0075] When D3<D0≤D4, the third preset adjustment coefficient X3 is selected to adjust the working condition matrix AI of the ammonia injection device, and the adjusted working condition matrix is ​​AI(AI*X3, BI*X3);

[0076] When D4<D0, the fourth preset adjustment coefficient X4 is selected to adjust the working condition matrix AI of the ammonia injection device, and the adjusted working condition matrix is ​​AI (AI*X4, BI*X4).

[0077] In the embodiment of the present application, the acquisition module is used to obtain the ammonia slip amount detected by the current ammonia slip amount detection sensor, and the processing module is used to adjust the working condition matrix AI (AI* XI , BI* XI ) is corrected, where

[0078] Obtain denitrification efficiency and ammonia escape amount, and perform normalization processing on the denitrification efficiency and ammonia escape amount respectively;

[0079] Obtain target ratio data, and determine the target ratio of denitrification efficiency and ammonia escape amount after normalization according to the target ratio data;

[0080] Determine the target ammonia escape amount according to the target ratio of the denitration efficiency and the ammonia escape amount after normalization and the current denitration efficiency, and calculate the difference C0 between the current ammonia escape amount and the target ammonia escape amount;

[0081] A first preset difference C1, a second preset difference C2, a third preset difference C3 and a fourth preset difference C4 are preset, and C1<C2<C3<C4; a first preset correction coefficient Y1, a second preset correction coefficient Y2, a third preset correction coefficient Y3 and a fourth preset correction coefficient Y4 are preset, and 1>Y1>Y2>Y3>Y4>0.7;

[0082] The processing module is also used to modify the adjusted working condition matrix AI (AI*XI, BI*XI) of the ammonia injection device according to the relationship between the difference C0 between the current ammonia slip amount and the target ammonia slip amount and each preset difference;

[0083] When C0≤C1, the working condition matrix AI (AI*XI, BI*XI) of the ammonia injection device is not corrected;

[0084] When C1<C0≤C2, the first preset correction coefficient Y1 is selected to correct the working condition matrix AI (AI*XI, BI*XI) of the ammonia injection device, and the corrected working condition matrix is ​​AI (AI*XI*Y1, BI*XI*Y1);

[0085] When C2<C0≤C3, the second preset correction coefficient Y2 is selected to correct the working condition matrix AI (AI*XI, BI*XI) of the ammonia injection device, and the corrected working condition matrix is ​​AI (AI*XI*Y2, AI*XI*Y2);

[0086] When C3<C0≤C4, the third preset correction coefficient Y3 is selected to correct the working condition matrix AI (AI*XI, BI*XI) of the ammonia injection device, and the corrected working condition matrix is ​​AI (AI*XI*Y3, AI*XI*Y3);

[0087] When C4<CI, the fourth preset correction coefficient Y4 is selected to correct the working condition matrix AI (AI*XI, BI*XI) of the ammonia injection device, and the corrected working condition matrix is ​​AI (AI*XI*Y4, AI*XI*Y4).

[0088] In summary, the embodiment of the present invention provides an ammonia spraying control system based on SCR flue gas denitrification, which includes: an SCR reactor, a flow detection sensor for detecting the amount of smoke entering the SCR reactor; a first NOx concentration detection sensor for detecting the NOx concentration data in the incoming smoke; a second NOx concentration detection sensor for detecting the NOx concentration data in the exhaust smoke; an ammonia escape detection sensor for detecting the ammonia escape data in the flue; an ammonia spraying device for spraying ammonia into the SCR reactor; and a control unit for setting, correcting and adjusting the working conditions of the ammonia spraying device according to the detected data. In the present invention, a control unit is provided on the SCR reactor, and the initial working conditions of the ammonia spraying device are set according to the detected data, and the initial working conditions are timely corrected and adjusted according to the subsequently detected data, so that the ammonia spraying device can select a precise amount of ammonia spraying to denitrify the flue gas, thereby improving the SCR flue gas denitrification efficiency while ensuring economy.

[0089] Finally, it should be noted that it is obvious that those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include these modifications and variations.

[0090] The above is only an example of implementation of the present invention, but it cannot be used to limit the scope of the present invention. Any structural changes made according to the present invention, as long as they do not lose the essence of the present invention, should be regarded as falling within the scope of protection of the present invention and being restricted. Those skilled in the art can clearly understand that for the convenience and simplicity of description, the specific working process and related instructions of the system described above can refer to the corresponding process in the aforementioned method embodiment, and will not be repeated here.

[0091] The term "comprise" or any other similar term is intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus / device that includes a list of elements includes not only those elements but also other elements not expressly listed, or also includes elements inherent to such process, method, article, or apparatus / device.

[0092] So far, the technical solutions of the present invention have been described in conjunction with the further embodiments shown in the accompanying drawings, but it is easy for those skilled in the art to understand that the protection scope of the present invention is obviously not limited to these specific embodiments. Without departing from the principle of the present invention, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after these changes or substitutions will fall within the protection scope of the present invention.

[0093] The above description is only a preferred embodiment of the present invention and is not intended to limit the protection scope of the present invention.

Claims

1. An ammonia injection control system based on SCR flue gas denitrification, characterized in that: include: An SCR reactor connected to the combustion furnace; A flow detection sensor is arranged in the smoke inlet duct of the SCR reactor, and is used to detect the amount of smoke entering the SCR reactor; A first NOx concentration detection sensor is arranged in the smoke inlet duct of the SCR reactor, and the first NOx concentration detection sensor is used to detect NOx concentration data in the smoke inlet; A second NOx concentration detection sensor is disposed in the smoke outlet of the SCR reactor, and the second NOx concentration detection sensor is used to detect NOx concentration data in the exhaust smoke; an ammonia escape amount detection sensor, arranged in the flue gas duct of the SCR reactor, and used to detect the ammonia escape amount data of the flue gas duct; an ammonia spraying device, arranged in the flue gas inlet of the SCR reactor, and used for spraying ammonia gas into the SCR reactor; The control unit is electrically connected to the flow detection sensor, the first NOx concentration detection sensor, the second NOx concentration detection sensor, the ammonia slip detection sensor, and the ammonia injection device, respectively. The control unit is used to set, correct and adjust the working conditions of the ammonia injection device according to the detected data.

2. The ammonia injection control system based on SCR flue gas denitrification according to claim 1 is characterized in that: The control unit comprises: A collection module, respectively connected to the flow detection sensor, the first NOx concentration detection sensor, the second NOx concentration detection sensor, and the ammonia escape detection sensor, the collection module is used to collect data parameters of the flow detection sensor, the first NOx concentration detection sensor, the second NOx concentration detection sensor, and the ammonia escape detection sensor, and transmit the data parameters to the processing module; A processing module connected to the acquisition module, the processing module is used to set a working state instruction of the ammonia injection device according to the data parameters; A control module is connected to the processing module and to the ammonia injection device, and the control module is used to control the ammonia injection device according to the working state instruction set by the processing module.

3. The ammonia injection control system based on SCR flue gas denitrification according to claim 2 is characterized in that: The acquisition module is used to acquire the smoke intake volume ΔG detected by the flow detection sensor, and the control module is used to control the ammonia spraying device; The processing module is used to set the preset value G0 of the smoke intake amount, and the processing module is also used to set the first preset smoke intake amount difference g1, the second preset smoke intake amount difference g2, the third preset smoke intake amount difference g3 and the fourth preset smoke intake amount difference g4, and g1<g2<g3<g4; the processing module is also used to set the first preset working condition matrix A1 (a1, b1), the second preset working condition matrix A2 (a2, b2), the third preset working condition matrix A3 (a3, b3) and the fourth preset working condition matrix A4 (a4, b4), wherein a1-a4 are respectively the first ammonia injection device rod to the fourth preset ammonia injection flow rate, and a1<a2<a3<a4, b1-b4 are respectively the first ammonia injection device rod to the fourth preset ammonia injection time, and b1<b2<b3<b4; According to the difference between the smoke intake volume △G detected by the flow detection sensor and the preset value G0 of the smoke intake volume detected by the set flow detection sensor, a preset working condition matrix A is selected as the working condition of the ammonia spraying device; When △G-G0≤g1, the first preset working condition matrix A1 is selected as the working condition of the ammonia injection device; When g1<△G-G0≤g2, the second preset working condition matrix A2 is selected as the working condition of the ammonia injection device; When g2<△G-G0≤g3, the third preset working condition matrix A3 is selected as the working condition of the ammonia injection device; When g3<△G-G0≤g4, the fourth preset working condition matrix A4 is selected as the working condition of the ammonia injection device; Among them, when the i-th preset working condition matrix Ai is selected as the working condition of the ammonia injection device, the control module controls the ammonia injection device to operate at the i-th preset ammonia injection flow rate ai, and the control module will also control the ammonia injection device to operate at the i-th preset ammonia injection duration bi, i=1, 2, 3, 4.

4. The ammonia injection control system based on SCR flue gas denitrification according to claim 3 is characterized in that: The processing module is used to determine whether to adjust the working condition matrix Ai of the ammonia injection device according to the denitration efficiency of the SCR reactor; If the calculated denitration efficiency of the SCR reactor meets the standard, there is no need to adjust the working condition matrix Ai of the ammonia injection device; If the calculated denitration efficiency of the SCR reactor does not meet the standard, the working condition matrix Ai of the ammonia injection device needs to be adjusted.

5. The ammonia injection control system based on SCR flue gas denitrification according to claim 4 is characterized in that: The processing module is used to calculate the denitrification efficiency of the SCR reactor based on the data detected by the first NOx concentration detection sensor and the second NOx concentration detection sensor collected by the collection module, and the formula n=1-(m1÷m2)×100% is used to calculate the denitrification efficiency of the SCR reactor, wherein n is the denitrification efficiency, m1 is the concentration of NOx in the exhaust smoke detected by the second NOx concentration detection sensor, and m2 is the concentration of NOx in the intake smoke detected by the first NOx concentration detection sensor.

6. The ammonia injection control system based on SCR flue gas denitrification according to claim 4 is characterized in that: If the calculated denitration efficiency of the SCR reactor does not meet the standard, the working condition matrix Ai of the ammonia injection device needs to be adjusted, including: The processing module is used to obtain the working condition matrix Ai (ai, bi) of the ammonia injection device, i = 1, 2, 3, 4; The processing module is further used to obtain a denitration efficiency value d0 of the SCR reactor, and the processing module is used to pre-set a first preset denitration efficiency value d1, a second preset denitration efficiency value d2, a third preset denitration efficiency value d3, and a fourth preset denitration efficiency value d4, and d1<d2<d3<d4; the processing module is also used to pre-set a first preset adjustment coefficient x1, a second preset adjustment coefficient x2, a third preset adjustment coefficient x3, and a fourth preset adjustment coefficient x4, and 1>x1>x2>x3>x4>0.5; The processing module is also used to adjust the working condition matrix Ai (ai, bi) of the ammonia injection device according to the relationship between the obtained denitration efficiency value of the SCR reactor and each preset denitration efficiency value: When d0≤d1, the working condition matrix Ai of the ammonia injection device is not adjusted; When d1<d0≤d2, the first preset adjustment coefficient x1 is selected to adjust the working condition matrix Ai of the ammonia injection device, and the adjusted working condition matrix is ​​Ai(ai*x1,bi*x1); When d2<d0≤d3, the second preset adjustment coefficient x2 is selected to adjust the working condition matrix Ai of the ammonia injection device, and the adjusted working condition matrix is ​​Ai(ai*x2,bi*x2); When d3<d0≤d4, the third preset adjustment coefficient x3 is selected to adjust the working condition matrix Ai of the ammonia injection device, and the adjusted working condition matrix is ​​Ai(ai*x3,bi*x3); When d4<d0, the fourth preset adjustment coefficient x4 is selected to adjust the working condition matrix Ai of the ammonia injection device, and the adjusted working condition matrix is ​​Ai(ai*x4,bi*x4).

7. The ammonia injection control system based on SCR flue gas denitrification according to claim 6 is characterized in that: The acquisition module is used to obtain the ammonia slip amount detected by the current ammonia slip amount detection sensor, and the processing module is used to correct the adjusted working condition matrix Ai (ai*xi, bi*xi) of the ammonia injection device according to the ammonia slip amount, wherein: Obtain denitrification efficiency and ammonia escape amount, and perform normalization processing on the denitrification efficiency and ammonia escape amount respectively; Obtain target ratio data, and determine the target ratio of denitrification efficiency and ammonia escape amount after normalization according to the target ratio data; Determine the target ammonia slip amount according to the target ratio of the denitration efficiency and the ammonia slip amount after normalization and the current denitration efficiency, and calculate the difference c0 between the current ammonia slip amount and the target ammonia slip amount; A first preset difference c1, a second preset difference c2, a third preset difference c3 and a fourth preset difference c4 are preset, and c1<c2<c3<c4; a first preset correction coefficient y1, a second preset correction coefficient y2, a third preset correction coefficient y3 and a fourth preset correction coefficient y4 are preset, and 1>y1>y2>y3>y4>0.7; The processing module is also used to modify the adjusted working condition matrix Ai (ai*xi, bi*xi) of the ammonia injection device according to the relationship between the difference c0 between the current ammonia slip amount and the target ammonia slip amount and each preset difference; When c0≤c1, the working condition matrix Ai(ai*xi,bi*xi) of the ammonia injection device is not corrected; When c1<c0≤c2, the first preset correction coefficient y1 is selected to correct the working condition matrix Ai(ai*xi, bi*xi) of the ammonia injection device, and the corrected working condition matrix is ​​Ai(ai*xi*y1, bi*xi*y1); When c2<c0≤c3, the second preset correction coefficient y2 is selected to correct the working condition matrix Ai(ai*xi, bi*xi) of the ammonia injection device, and the corrected working condition matrix is ​​Ai(ai*xi*y2, ai*xi*y2); When c3<c0≤c4, the third preset correction coefficient y3 is selected to correct the working condition matrix Ai(ai*xi, bi*xi) of the ammonia injection device, and the corrected working condition matrix is ​​Ai(ai*xi*y3, ai*xi*y3); When c4<ci, the fourth preset correction coefficient y4 is selected to correct the working condition matrix Ai(ai*xi, bi*xi) of the ammonia injection device, and the corrected working condition matrix is ​​Ai(ai*xi*y4, ai*xi*y4).

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