A circulating fluidized bed boiler wide load denitration system and operation method

Abstract

The present invention relates to a wide-load denitration system for a circulating fluidized bed boiler and an operation method thereof, comprising a boiler, a cyclone, a reducing agent tank and a buffer tank; a first spray gun is arranged on the inner wall of the upper part of the boiler, and a second spray gun is arranged on the inner wall of the pipe at the outlet of the cyclone; the reducing agent tank and the buffer tank are connected to a first liquid inlet pipe, and the first liquid inlet pipe is sequentially connected to a first control valve and a first delivery pump; the first spray gun and the second spray gun are respectively connected to the buffer tank via a second liquid inlet pipe and a third liquid inlet pipe, the second liquid inlet pipe is connected to a second control valve, and the third liquid inlet pipe is connected to a third control valve, and the first spray gun, the second spray gun, the first control valve, the second control valve, the third control valve and the first delivery pump are all electrically connected to an external control system; the system can realize stable NOx control under low load, thereby realizing efficient, stable and precise control of NOx when the circulating fluidized bed boiler is operating under wide load.

Description

Technical Field

[0001] The invention relates to the technical field of circulating fluidized bed denitration, and in particular to a circulating fluidized bed boiler wide load denitration system and an operation method. Background Art

[0002] Circulating fluidized bed boiler flue gas denitrification usually adopts SNCR denitrification process. Since SNCR does not use catalysts, when urea is used as a reducing agent, the operating temperature is required to be 900-1150℃. The appropriate temperature window is crucial to improving denitrification efficiency, reducing reducing agent consumption and reducing ammonia slip. Therefore, in actual use, the reaction temperature range required by the reducing agent should be selected, and the appropriate reducing agent spray gun layout area can directly improve the denitrification effect.

[0003] The operating temperature range of the circulating fluidized bed boiler coincides with the temperature window required for the SNCR denitrification reaction. The initial NOx emission concentration of the boiler is low, and the use of SNCR can meet the emission requirements. Therefore, SNCR denitrification technology has a natural advantage in the application of circulating fluidized bed units. However, when the circulating fluidized bed boiler operates at a wide load, the furnace temperature is low under low load conditions, and the temperature in the reducing agent injection area is outside the temperature window for efficient operation of the SNCR, resulting in low denitrification efficiency, difficulty in meeting emission standards, and large ammonia escape.

[0004] In order to achieve stable NOx control over a wide load for circulating fluidized bed boilers, it is necessary to further broaden the temperature window of the SNCR denitrification process. At the same time, the reductant spray gun is optimized for the boiler operating temperature range. A wide load denitrification system and operation method for circulating fluidized bed boilers are proposed. Summary of the invention

[0005] The present invention provides a circulating fluidized bed boiler wide load denitration system and operation method, which can achieve stable NOx control even under low load conditions, thereby achieving efficient, stable and precise control of NOx when the circulating fluidized bed boiler is operating at a wide load.

[0006] To achieve the above object, the present invention adopts the following technical solutions:

[0007] A circulating fluidized bed boiler wide load denitration system, comprising a boiler, a cyclone, a reducing agent tank and a buffer tank;

[0008] A first spray gun is arranged on the inner wall of the upper part of the boiler, and a second spray gun is arranged on the inner wall of the pipe at the outlet of the cyclone;

[0009] The reducing agent tank is connected to the buffer tank via a first liquid inlet pipe, and the first liquid inlet pipe is connected to a first delivery pump and a first control valve in sequence;

[0010] The first spray gun and the second spray gun are connected to the buffer tank via a second liquid inlet pipe and a third liquid inlet pipe, respectively. The second liquid inlet pipe is connected to a second control valve, and the third liquid inlet pipe is connected to a third control valve.

[0011] The first spray gun, the second spray gun, the first control valve, the second control valve, the third control valve and the first delivery pump are all electrically connected to an external control system.

[0012] Preferably, the number of the above-mentioned first spray guns is at least two, which are vertically distributed on the upper inner wall of the above-mentioned boiler, the number of the above-mentioned second liquid inlet pipes is at least two, and the multiple first spray guns are connected to the multiple second liquid inlet pipes in a one-to-one correspondence. A first temperature measuring device is provided at any of the above-mentioned first spray guns, and the above-mentioned first temperature measuring device is electrically connected to the external control system.

[0013] Preferably, any one of the second liquid inlet pipes is also connected to a first flow meter, and the first flow meter is electrically connected to an external control system.

[0014] Preferably, the number of the above-mentioned second spray guns is at least two, which are vertically distributed on the inner wall of the pipe at the outlet of the above-mentioned cyclone, the number of the above-mentioned third liquid inlet pipes is at least two, and the multiple number of the above-mentioned second spray guns are connected to the multiple third liquid inlet pipes one-to-one, and any of the above-mentioned second spray guns is provided with a second temperature measuring device, and the above-mentioned second temperature measuring device is electrically connected to the external control system.

[0015] Preferably, any one of the third liquid inlet pipes is also connected to a second flow meter, and the second flow meter is electrically connected to an external control system.

[0016] Preferably, it further comprises an active agent solution tank, wherein the buffer tank is provided with a first chamber and a second chamber, a fourth liquid inlet pipe is connected between the active agent solution tank and the second chamber, and a second delivery pump and a fourth control valve are connected to the fourth liquid inlet pipe;

[0017] The first liquid inlet pipe includes a fifth liquid inlet pipe connected to the reducing agent tank and a sixth liquid inlet pipe connected to the first chamber, the first delivery pump is arranged on the fifth liquid inlet pipe, the first control valve is arranged on the sixth liquid inlet pipe, a seventh liquid inlet pipe is further connected between the fifth liquid inlet pipe and the second chamber, the seventh liquid inlet pipe is connected to the fifth control valve, and the fourth control valve and the fifth control valve are both electrically connected to an external control system;

[0018] The second liquid inlet pipe is communicated with the first cavity, and the third liquid inlet pipe is communicated with the second cavity.

[0019] A method for operating a denitration system, comprising:

[0020] When the boiler is in the 60%-100% load operation stage, the second spray gun at the outlet of the cyclone is opened, the first spray gun is closed, the first delivery pump, the third control valve and the fifth control valve are opened, and the remaining valves are closed;

[0021] When the boiler is in the 40%-60% load operation stage, the second spray gun at the outlet of the cyclone is opened, the first spray gun is closed, the first delivery pump, the second delivery pump, the third control valve, the fourth control valve and the fifth control valve are opened, and the remaining valves are closed;

[0022] When the boiler is in the load operation stage below 40%, open the second spray gun at the cyclone outlet and the first spray gun at the boiler, and open the first delivery pump, the second delivery pump, the first control valve, the second control valve, the third control valve, the fourth control valve and the fifth control valve.

[0023] Preferably, when the boiler is in the 40%-60% load operation stage, the second delivery pump and the fourth control valve are opened only when the second temperature measuring device at the cyclone outlet measures the flue gas temperature to be lower than 900°C.

[0024] Preferably, when the flue gas temperature at the cyclone outlet is 850-900°C, the amount of active agent added is not higher than 10% of the total amount of reducing agent; when the flue gas temperature at the cyclone outlet is 800-850°C, the amount of active agent added is not higher than 15% of the total amount of reducing agent; when the flue gas temperature at the cyclone outlet is 700-800°C, the amount of active agent added is not higher than 20% of the total amount of reducing agent.

[0025] Preferably, the second delivery pump and the fourth control valve are opened only when the smoke temperature measured by the second temperature measuring device at the outlet of the cyclone is lower than 900°C;

[0026] When the smoke temperature at the cyclone outlet is 850-900°C, the amount of active agent added is not higher than 10% of the total amount of reducing agent; when the smoke temperature at the cyclone outlet is 800-850°C, the amount of active agent added is not higher than 15% of the total amount of reducing agent; when the smoke temperature at the cyclone outlet is 700-800°C, the amount of active agent added is not higher than 20% of the total amount of reducing agent; when the smoke temperature at the cyclone outlet is lower than 700, the addition of active agent is stopped, the second spray gun is closed, and only the first spray gun is opened.

[0027] Compared with the prior art, the present invention has the following beneficial effects:

[0028] A circulating fluidized bed boiler wide load denitration system is provided on the basis of the prior art. A first spray gun is arranged on the upper inner wall of the boiler. When the boiler is in a high load working condition, the second spray gun works normally to complete the denitration work. When the boiler is in a low load working condition, the first spray gun and the second spray gun can be opened at the same time to spray a reducing agent to carry out the denitration work, so that the denitration efficiency is greatly improved. When the temperature of the second spray gun is lower than the reaction temperature of the reducing agent, only the first spray gun is opened to carry out the denitration work in the boiler, thereby ensuring the denitration efficiency and meeting the emission standards without causing the problems of low denitration efficiency, difficulty in meeting the emission standards, large ammonia escape, etc., thereby realizing wide load stable NOx control.

[0029] An operating method for a circulating fluidized bed boiler wide load denitration system controls the opening and closing of a first spray gun and a second spray gun under different load stages of the boiler to ensure denitration efficiency, and at the same time adjusts the injection amount of a reducing agent at each spray gun by detecting the temperature at the first spray gun and the second spray gun, so that the reducing agent fully reacts with the flue gas without wasting the amount of reducing agent used, and the use effect is good. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0031] Figure 1 It is the overall framework diagram of the denitration system in the embodiment of the present invention;

[0032] Figure 2 This is a system working framework diagram when the boiler is in the 60%-100% operation process in an embodiment of the present invention;

[0033] Figure 3 This is a system working framework diagram when the boiler is in the 40%-60% operation process in the embodiment of the present invention;

[0034] Figure 4 This is the overall framework diagram of the prior art.

[0035] Description of reference numerals:

[0036] 1. Boiler; 2. Cyclone; 3. Reductant tank; 4. Buffer tank; 41. First chamber; 42. Second chamber; 5. First spray gun; 6. First temperature measuring device; 7. Second spray gun; 8. Second temperature measuring device; 9. First control valve; 10. First delivery pump; 11. Second control valve; 12. Third control valve; 13. First flow meter; 14. Second flow meter; 15. Active agent solution tank; 16. Second delivery pump; 17. Fourth control valve; 18. Fifth control valve. DETAILED DESCRIPTION

[0037] The technical solution of the present invention will be described clearly and completely below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0038] In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", and "third" are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance.

[0039] In the description of the present invention, 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 the present invention can be understood according to specific circumstances.

[0040] The embodiment of the present invention provides a circulating fluidized bed boiler 1 wide load denitration system, such as Figure 1As shown, it includes a boiler 1, a cyclone 2, a reducing agent tank 3 and a buffer tank 4; the lower inner cavity of the boiler 1 is connected to the lower inner cavity of the cyclone 2, and the upper inner cavity is connected to the upper inner cavity of the cyclone 2. A first spray gun 5 is arranged on the upper inner wall of the boiler 1, and a second spray gun 7 is arranged on the inner wall of the pipe at the outlet of the cyclone 2; the reducing agent tank 3 is connected to the buffer tank 4 with a first liquid inlet pipe, and the first liquid inlet pipe is connected to a first delivery pump 10 and a first control valve 9 in sequence; the first spray gun 5 and the second spray gun 7 are connected to the buffer tank 4 with a second liquid inlet pipe and a third liquid inlet pipe respectively, the second liquid inlet pipe is connected to a second control valve 11, and the third liquid inlet pipe is connected to a third control valve 12; the first spray gun 5, the second spray gun 7, the first control valve 9, the second control valve 11, the third control valve 12 and the first delivery pump 10 are all electrically connected to an external control system. Specifically, the reducing agent is a urea solution.

[0041] Specifically, according to the different load stages of the boiler 1, the operator opens and closes the first spray gun 5 and the second spray gun 7 through an external control system (a power plant control system). Specifically, when the boiler is in the 60%-100% load operation stage, the second spray gun 7 is opened and the first spray gun 5 is closed; when the boiler is in the 40%-60% load operation stage, the second spray gun 7 is opened and the first spray gun 5 is closed; when the boiler is in the 40% load operation stage, the second spray gun 7 and the first spray gun 5 are opened, thereby ensuring the denitrification efficiency of the circulating fluidized bed at each stage.

[0042] Preferably, there are at least two first spray guns 5 vertically distributed on the upper inner wall of the boiler 1, there are at least two second liquid inlet pipes, the number of the multiple first spray guns 5 is connected to the multiple second liquid inlet pipes in a one-to-one correspondence, and a first temperature measuring device 6 is provided at any first spray gun 5, and the first temperature measuring device 6 is electrically connected to the external control system. Specifically, there are three second liquid inlet pipes, three first temperature measuring devices 6 and three first spray guns 5, and the three first spray guns 5 are arranged on the upper inner wall of the boiler 1. The three first temperature measuring devices 6 control the opening of each second control valve 11 according to the measured flue gas temperature, so as to avoid excessive spraying of the reducing agent and realize stable and precise control of the reducing agent. Moreover, when the three first spray guns 5 work at the same time, the denitrification efficiency is high. Specifically, the first temperature measuring device 6 is a high-temperature resistant commercially available temperature sensor, which is generally a thermometer commonly used in the denitrification process.

[0043] Preferably, any one of the second liquid inlet pipes is also connected to a first flow meter 13, which is electrically connected to an external control system. When the first spray gun 5 is working, the amount of reducing agent sprayed by the first spray gun 5 can be stably measured, thereby accurately controlling the opening of the second control valve 11, and cooperating with the first temperature measuring device 6 to achieve accurate control of the SNCR reducing agent.

[0044] Preferably, there are at least two second spray guns 7, which are vertically distributed on the inner wall of the pipe at the outlet of the cyclone barrel 2. There are at least two second liquid inlet pipes. The number of multiple second spray guns 7 is connected to the multiple second liquid inlet pipes in a one-to-one correspondence. A second temperature measuring device 8 is provided at any second spray gun 7, and the second temperature measuring device 8 is electrically connected to the external control system. Specifically, there are three second liquid inlet pipes, three second temperature measuring devices 8 and second spray guns 7. The three second spray guns 7 are arranged on the inner wall of the pipe at the outlet of the cyclone barrel 2. The three second temperature measuring devices 8 control the opening of their respective third control valves 12 according to the measured flue gas temperature, so as to avoid excessive spraying of the reducing agent and realize stable and precise control of the reducing agent. Moreover, when the three second spray guns 7 work at the same time, the denitrification efficiency is high. Specifically, the second temperature measuring device 8 is a high-temperature resistant commercially available temperature sensor, which is generally a thermometer commonly used in the denitrification process.

[0045] Preferably, any one of the third liquid inlet pipes is also connected to a second flow meter 14, which is electrically connected to the external control system. When the second spray gun 7 is working, the amount of reducing agent sprayed by the second spray gun 7 can be stably measured, thereby accurately controlling the opening of the third control valve 12, and cooperating with the second temperature measuring device 8 to achieve accurate control of the SNCR reducing agent.

[0046] Preferably, it also includes an active agent solution tank 15, the buffer tank 4 is divided into a first chamber 41 and a second chamber 42, a fourth liquid inlet pipe is connected between the active agent solution tank 15 and the second chamber 42, and the fourth liquid inlet pipe is connected to a second delivery pump 16 and a fourth control valve 17; the first liquid inlet pipe includes a fifth liquid inlet pipe connected to the reducing agent tank 3 and a sixth liquid inlet pipe connected to the first chamber 41, the first delivery pump 10 is arranged on the fifth liquid inlet pipe, the first control valve 9 is arranged on the sixth liquid inlet pipe, and a seventh liquid inlet pipe is also connected between the fifth liquid inlet pipe and the second chamber 42, and the seventh liquid inlet pipe is connected to a fifth control valve 18, and the fourth control valve 17 and the fifth control valve 18 are both electrically connected to the external control system; the second liquid inlet pipe is connected to the first chamber 41, and the third liquid inlet pipe is connected to the second chamber 42; the first spray gun 5 is connected to the first chamber 41, and the first chamber 41 is connected to the reducing agent tank 3. When the first spray gun 5 is working, the reducing agent is sprayed out of the first spray gun 5, because the first spray gun 5 The gun 5 is located at the upper part of the boiler 1, and its temperature can reach the window of the reducing agent reaction, so the use effect is better; the second spray gun 7 is connected to the second chamber 42, and the second chamber 42 is connected to the reducing agent tank 3 and the activating agent tank. The flue gas temperature in the reducing agent injection area at the upper part of the cyclone 2 is within the temperature window of the efficient operation of the SNCR. The second chamber 42 contains the reducing agent solution, so that the reducing agent reacts normally with the flue gas for denitrification. When the flue gas temperature in the reducing agent injection area at the upper part of the cyclone 2 is outside the temperature window of the efficient operation of the SNCR, that is, when the temperature is low, the second chamber 42 contains a mixture of the activating agent and the reducing agent. The second spray gun 7 sprays the mixture of the activating agent and the reducing agent, which can ensure the denitrification efficiency. Adding the activating agent tank can not only increase the denitrification efficiency of the flue gas at low temperature, but also expand the window of the reducing agent reaction temperature, so that the temperature window is reduced by 700°C from the original minimum of 800°C, and the denitrification effect is better.

[0047] Specifically, the second cavity 42 is connected to the first liquid outlet pipe, the three third liquid inlet pipes are all connected to the first liquid outlet pipe, the first cavity 41 is connected to the second liquid outlet pipe, and the three second liquid inlet pipes are all connected to the second liquid outlet pipe, so that the pipeline is more streamlined.

[0048] Specifically, the second chamber 42 and the first chamber 41 are connected to the first water pipe and the second water pipe respectively, and the first water pipe and the second water pipe are connected to the sixth control valve and the seventh control valve respectively. The sixth control valve and the seventh control valve are electrically connected to the external control system. When the concentration of the solution in the second chamber 42 and the first chamber 41 needs to be reduced, the sixth control valve and the seventh control valve can be used to make it reach the required concentration before use.

[0049] A method for operating a denitration system, comprising:

[0050] like Figure 2As shown, when the boiler is in the 60%-100% load operation stage, the temperature at the second spray gun 7 is in the temperature window of the reductant injection area and the SNCR is in the efficient operation temperature window, the second spray gun 7 at the outlet of the cyclone 2 is opened, the first spray gun 5 is closed, the first delivery pump 10, the third control valve 12 and the fifth control valve 18 are opened, the second delivery pump 16, the first control valve 9, the second control valve 11 and the fourth control valve 17 are closed, the reductant in the reductant tank 3 enters the second chamber 42, and the concentration of the reductant is adjusted by opening the sixth control valve as needed, and then the reductant enters the second spray gun 7 through the first liquid outlet pipe and the third liquid inlet pipe, and the reductant is sprayed out to perform denitration.

[0051] like Figure 3 As shown, when the boiler is in the 40%-60% load operation stage, the second spray gun 7 at the outlet of the cyclone 2 is opened, the first spray gun 5 is closed, the temperature at the second spray gun 7 is in the temperature window of the reducing agent injection area and the temperature window of the SNCR efficient operation, the first delivery pump 10, the third control valve 12 and the fifth control valve 18 are opened, the second delivery pump 16, the first control valve 9, the second control valve 11 and the fourth control valve 17 are closed, under the action of the first delivery pump 10, the second chamber 42 is filled with the reducing agent solution, the reducing agent solution is sprayed out through the second spray gun 7 to perform denitration work; the temperature at the second spray gun 7 is in the temperature window of the reducing agent injection area and the temperature window of the SNCR efficient operation, that is, when the second temperature measuring device 8 at the outlet of the cyclone 2 measures the flue gas temperature to be lower than 900°C, the second delivery pump 16 and the fourth control valve 17 are opened, through the action of the first delivery pump 10 and the second delivery pump 16, the reducing agent and the activating agent both enter the second chamber 42, and the second chamber 42 is filled with the reducing agent solution. The mixed solution of the original agent and the activator is sprayed out through the second spray gun 7 to carry out denitrification. Specifically, the proportion and dosage of the reducing agent and the activator in the total solution are controlled by the coordinated use of the second temperature measuring device 8, the third control valve 12, the fourth control valve 17, the fifth control valve 18 and the second flow meter 14 to avoid excessive use of the activator, thereby increasing the use cost. Specifically, when the flue gas temperature at the outlet of the cyclone 2 is 850-900°C, the amount of the activator added is not more than 10% of the total amount of the reducing agent; when the flue gas temperature at the outlet of the cyclone 2 is 800-850°C, the amount of the activator added is not more than 15% of the total amount of the reducing agent; when the flue gas temperature at the outlet of the cyclone 2 is 700-800°C, the amount of the activator added is not more than 20% of the total amount of the reducing agent; when the flue gas temperature at the outlet of the cyclone 2 is lower than 700, the addition of the activator is stopped, the second spray gun 7 and the corresponding valves are closed, only the first spray gun 5 is opened, and the first delivery pump 10, the first control valve 9 and the second control valve 11 are opened accordingly.

[0052] like Figure 1As shown, when the boiler is in the load operation stage below 40%, the second spray gun 7 at the outlet of the cyclone 2 and the first spray gun 5 at the boiler 1 are opened, the temperature at the second spray gun 7 is in the reducing agent injection area and the temperature is in the temperature window of SNCR efficient operation, the first delivery pump 10, the first control valve 9, the second control valve 11, the third control valve 12 and the fifth control valve 18 are opened, and through the action of the first delivery pump 10, the reducing agent solution enters the second chamber 42 and the first chamber 41, and the reducing agent solution enters the first spray gun 5 and the second spray gun 7 and is sprayed out. At this time, the spraying amount of the first spray gun 5 can be appropriately reduced, and the spraying amount of the second spray gun 7 can be increased to carry out denitration work and ensure the denitration efficiency; when the second temperature measuring device 8 at the outlet of the cyclone 2 measures the flue gas temperature below 900°C, the second delivery pump 16 and the fourth control valve 17 are opened, and through the action of the first delivery pump 10 and the second delivery pump 16, the first chamber 41 is still filled with reducing agent solution, the first spray gun 5 sprays reducing agent, and the reducing agent and the activating agent both enter the second The second chamber 42 contains a mixed solution of the reducing agent and the activating agent, which is sprayed out through the second spray gun 7 to perform denitration. Specifically, the proportion of the reducing agent and the activating agent in the total solution and their usage are controlled by the cooperation of the second temperature measuring device 8, the third control valve 12, the fourth control valve 17, the fifth control valve 18 and the second flow meter 14 to avoid excessive use of the activating agent, thereby increasing the use cost. When the flue gas temperature at the outlet of the cyclone 2 is 850-900°C, the amount of activating agent added is Not higher than 10% of the total amount of reducing agent; when the flue gas temperature at the outlet of cyclone 2 is 800-850℃, the amount of active agent added is not higher than 15% of the total amount of reducing agent; when the flue gas temperature at the outlet of cyclone 2 is 700-800℃, the amount of active agent added is not higher than 20% of the total amount of reducing agent; when the flue gas temperature at the outlet of cyclone 2 is lower than 700, stop adding the active agent, close the second spray gun 7 and the corresponding valve, only open the first spray gun 5, and correspondingly open the first delivery pump 10, the first control valve 9 and the second control valve 11.

[0053] In summary, by controlling the opening and closing of the first spray gun 5 and the second spray gun 7 respectively under various load stages of the boiler 1 and different fuel conditions, the denitrification efficiency is ensured and the wide load stable NOx control of the circulating fluidized bed boiler 1 is achieved. At the same time, by detecting the temperature at the first spray gun 5 and the second spray gun 7, the injection amount of the reducing agent and the activating agent at each spray gun is adjusted, so that the reducing agent and the flue gas can fully react without wasting the amount of the reducing agent and the activating agent, and the use effect is good.

[0054] The above-mentioned embodiments are only preferred embodiments of the present invention and cannot be used to limit the scope of protection of the present invention. Any non-substantial changes and substitutions made by technicians in this field on the basis of the present invention shall fall within the scope of protection required by the present invention.

Claims

1. An operation method of a circulating fluidized bed boiler wide load denitration system, which is realized by a circulating fluidized bed boiler wide load denitration system, It is characterized in that The denitration system comprises a boiler, a cyclone, a reducing agent tank and a buffer tank; The upper inner wall of the boiler is provided with a first spray gun, and the inner wall of the pipe at the outlet of the cyclone is provided with a second spray gun; The reducing agent tank is connected to the buffer tank through a first liquid inlet pipe, and the first liquid inlet pipe is sequentially connected to a first delivery pump and a first control valve; The first spray gun and the second spray gun are connected to the buffer tank via a second liquid inlet pipe and a third liquid inlet pipe, respectively. The second liquid inlet pipe is connected to a second control valve, and the third liquid inlet pipe is connected to a third control valve. The first spray gun, the second spray gun, the first control valve, the second control valve, the third control valve and the first delivery pump are all electrically connected to an external control system; The denitration system further comprises an active agent solution tank, wherein the buffer tank is provided with a first chamber and a second chamber, a fourth liquid inlet pipe is connected between the active agent solution tank and the second chamber, and a second delivery pump and a fourth control valve are connected to the fourth liquid inlet pipe; The first liquid inlet pipe includes a fifth liquid inlet pipe connected to the reducing agent tank and a sixth liquid inlet pipe connected to the first chamber, the first delivery pump is arranged on the fifth liquid inlet pipe, the first control valve is arranged on the sixth liquid inlet pipe, a seventh liquid inlet pipe is further connected between the fifth liquid inlet pipe and the second chamber, the seventh liquid inlet pipe is connected to the fifth control valve, and the fourth control valve and the fifth control valve are both electrically connected to an external control system; The second liquid inlet pipe is in communication with the first cavity, and the third liquid inlet pipe is in communication with the second cavity; The operation method of the denitration system comprises: When the boiler is in the 60%-100% load operation stage, the second spray gun at the outlet of the cyclone is opened, the first spray gun is closed, the first delivery pump, the third control valve and the fifth control valve are opened, and the remaining valves are closed; When the boiler is in the 40%-60% load operation stage, the second spray gun at the outlet of the cyclone is opened, the first spray gun is closed, the first delivery pump, the second delivery pump, the third control valve, the fourth control valve and the fifth control valve are opened, and the remaining valves are closed; When the boiler is in the load operation stage below 40%, the second spray gun at the cyclone outlet and the first spray gun at the boiler are opened, and the first delivery pump, the second delivery pump, the first control valve, the second control valve, the third control valve, the fourth control valve and the fifth control valve are opened; And when the boiler is in the 40%-60% load operation stage, the second delivery pump and the fourth control valve are opened only when the second temperature measuring device at the cyclone outlet measures the flue gas temperature to be lower than 900°C.

2. The operating method according to claim 1, It is characterized in that The number of the first spray guns is at least two, which are vertically distributed on the upper inner wall of the boiler. The number of the second liquid inlet pipes is at least two. The multiple first spray guns are connected to the multiple second liquid inlet pipes in a one-to-one correspondence. A first temperature measuring device is provided at any one of the first spray guns, and the first temperature measuring device is electrically connected to an external control system.

3. The operating method according to claim 2, It is characterized in that Any one of the second liquid inlet pipes is also connected to a first flow meter, and the first flow meter is electrically connected to an external control system.

4. The operating method according to claim 1, It is characterized in that There are at least two second spray guns, which are vertically distributed on the inner wall of the pipe at the outlet of the cyclone. There are at least two third liquid inlet pipes. Multiple second spray guns are connected to multiple third liquid inlet pipes in a one-to-one correspondence. A second temperature measuring device is provided at any second spray gun, and the second temperature measuring device is electrically connected to an external control system.

5. The operating method according to claim 1, It is characterized in that Any one of the third liquid inlet pipes is also connected to a second flow meter, and the second flow meter is electrically connected to an external control system.

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