Precise ammonia spraying control device and method for circulating fluidized bed boiler

Abstract

The invention relates to the technical field of precise ammonia spraying control of fluidized bed boilers, in particular to a precise ammonia spraying control device and method of a circulating fluidized bed boiler, comprising a flue shell, one end of the flue shell is provided with an air inlet, the other end of the flue shell is provided with an air outlet, and the outer surface of one side of the flue shell is provided with a maintenance plate; an ammonia spraying mechanism is arranged on the inner wall of the flue shell, the ammonia spraying mechanism comprises a main pipe, multiple groups of flow guide pipes are connected to the outer surfaces of the two ends of the main pipe, and multiple groups of spraying heads are connected to the bottom ends of the multiple groups of flow guide pipes. According to the method, accurate matching of the ammonia gas and NOx is ensured, so that excessive use of the ammonia gas is reduced, and unnecessary waste and secondary pollution are avoided.

Description

Technical Field

[0001] The present invention relates to the technical field of precise ammonia injection control for fluidized bed boilers, and in particular to a precise ammonia injection control device and method for circulating fluidized bed boilers. Background Art

[0002] As a highly efficient and environmentally friendly coal-fired equipment, circulating fluidized bed boilers have been widely used in the power and industrial fields. In order to effectively control the emission of nitrogen oxides (NOx) during boiler operation, ammonia injection grids are usually used for denitrification. Ammonia injection grids spray ammonia water or ammonia gas into the flue gas to react chemically with NOx in the flue gas to generate harmless nitrogen and water vapor, thereby reducing NOx emissions.

[0003] However, the existing fluidized bed boiler control device has many deficiencies in the operation of the ammonia injection grid. First, most ammonia injection grids rely on manual valves for operation, which results in the inaccurate and inflexible adjustment of the amount of ammonia injection, making it difficult to meet the precise control requirements for NOx emissions during boiler operation. Second, the existing ammonia injection grid lacks an effective bypass mechanism, which makes the distribution of ammonia in the flue gas uneven, and it is easy for the local ammonia concentration to be too high or too low, which not only reduces the denitrification efficiency, but also easily causes corrosion and damage to the boiler equipment. Summary of the invention

[0004] (I) Purpose of the invention

[0005] In view of this, the purpose of the present invention is to provide a circulating fluidized bed boiler precise ammonia injection control device and method to solve the problems raised in the above background.

[0006] (II) Technical solution

[0007] A precise ammonia injection control device for a circulating fluidized bed boiler comprises a flue shell, one end of the flue shell is provided with an air inlet, and the other end of the flue shell is provided with an air outlet, an inspection plate is provided on the outer surface of one side of the flue shell, an ammonia injection mechanism is provided on the inner wall of the flue shell, the ammonia injection mechanism comprises a main pipe, and the outer surfaces of both ends of the main pipe are connected to multiple groups of guide pipes, and the bottom ends of the multiple groups of guide pipes are connected and installed with multiple groups of spray heads, a connecting pipe is connected to one side of the top end of the main pipe, and the connecting pipe passes through the outer surface of the flue shell, an electronic valve is provided on the outer surface of the connecting pipe, and one end of the connecting pipe is connected to a flow meter, and one end of the flow meter is connected to a connecting pipe, multiple groups of bypass mechanisms are provided on the outer surface of the top end of the main pipe, and the bypass mechanism comprises a mounting pipe, a motor is fixedly installed on the inner wall of the mounting pipe, and a shaft is connected to one end of the motor, multiple groups of stirring blades are fixedly installed on the outer surface of the shaft, and a top shell is provided on the top end of the mounting pipe.

[0008] Preferably, a heat dissipation groove is provided at the top of the top shell, and a first connecting plate is fixedly mounted on the outer surface of the top shell.

[0009] Preferably, a second connecting plate is fixedly mounted on the outer surface of the top end of the mounting tube, and the second connecting plate is connected to the first connecting plate via a plurality of sets of bolts.

[0010] Preferably, the inner wall of the flue shell is provided with a plurality of groups of guide plates, and the tops of the plurality of groups of guide plates are provided with a plurality of groups of sampling controllers, and the plurality of groups of sampling controllers are fixedly connected to the outer surface of one side of the flue shell.

[0011] Preferably, filter screens are installed on the outer surfaces of the bottom ends of the plurality of groups of spray heads.

[0012] Preferably, one end of the connecting pipe is connected with a flange.

[0013] A circulating fluidized bed boiler precise ammonia injection control method comprises the following steps:

[0014] 1. Device connection and preparation:

[0015] 1) Use the flange at one end of the connecting pipe to connect the ammonia spraying mechanism to the feed pipe (such as ammonia water or ammonia gas supply system) to ensure a stable supply of ammonia gas.

[0016] 2) Check and confirm that all parts are tightly connected and there is no leakage.

[0017] 3) Start the boiler and allow the flue gas to enter the flue shell through the air inlet.

[0018] 2. Real-time monitoring and data collection

[0019] 1) As the flue gas flows in the flue shell, multiple sets of sampling controllers monitor the NOx content in the flue gas in real time.

[0020] 2) The sampling controller transmits the detected NOx concentration data to the control system.

[0021] 3. Calculation and Control:

[0022] 1) The control system calculates the required ammonia injection amount based on the received NOx concentration data.

[0023] 2) By controlling the opening of the electronic valve and the reading of the flow meter, the flow rate of ammonia in the connecting pipe is adjusted to ensure that the amount of ammonia injected into the flue shell matches the concentration of NOx.

[0024] 4. Ammonia injection and mixing:

[0025] 1) After ammonia enters the main pipe through the connecting pipe, it is divided along the main pipe to multiple groups of guide pipes.

[0026] 2) The spray head at the top of the guide pipe sprays ammonia evenly into the flue gas in the form of fine droplets.

[0027] At the same time, the flow bypass mechanism at the top of the main pipe is driven by a motor, which drives the stirring blades to rotate through the shaft, generating airflow to disturb and mix the ammonia and flue gas, thereby improving the mixing efficiency.

[0028] 5. Reaction and Emission

[0029] 1) After precise injection and thorough mixing, ammonia reacts chemically with NOx in the flue gas to generate harmless nitrogen and water vapor.

[0030] 2) The treated flue gas is discharged from the boiler through the outlet.

[0031] 6. Feedback and Adjustment

[0032] 1) During the entire control process, the control system will continuously adjust the opening of the electronic valve and the flow meter reading based on the real-time monitored NOx concentration data and ammonia injection amount feedback.

[0033] 2) Ensure the stability and accuracy of denitrification effect through continuous adjustment and optimization.

[0034] It can be seen from the above technical solutions that the present application has the following beneficial effects:

[0035] 1. The invention monitors the concentration of NOx in the flue gas in real time and accurately calculates the required ammonia injection amount. This method ensures the precise matching of ammonia and NOx, thereby reducing the excessive use of ammonia and avoiding unnecessary waste and secondary pollution. In addition, the optimized design of the bypass mechanism and the spray head enhances the mixing effect of ammonia and flue gas, making the chemical reaction more complete and the denitrification efficiency higher. This precise control method not only improves the accuracy of denitrification, but also reduces the operating cost, providing a strong guarantee for the environmentally friendly operation of the boiler.

[0036] 2. Through continuous monitoring and feedback adjustment, the control system of the invention can timely detect and solve potential denitration problems, avoiding poor denitration effect or environmental pollution risks caused by insufficient or excessive ammonia injection. At the same time, the implementation of this method also helps to reduce dust accumulation and coking inside the boiler, extend the service life of the boiler, and reduce maintenance costs. In addition, precise control also makes the boiler more flexible and stable when dealing with different loads and working conditions, improving the overall operating efficiency and safety of the boiler.

[0037] 3. This invention effectively reduces the emission concentration of NOx in boiler flue gas and reduces the emission of atmospheric pollutants by precisely controlling the injection amount and mixing effect of ammonia, which plays a positive role in improving environmental quality and protecting the ecological environment. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 This is a schematic diagram of the first three-dimensional structure of the ammonia injection mechanism of the present invention;

[0039] Figure 2 It is a second three-dimensional structural schematic diagram of the ammonia injection mechanism of the present invention;

[0040] Figure 3 This is a schematic diagram of the explosion of the ammonia spraying mechanism of the present invention;

[0041] Figure 4 For the present invention Figure 3 The enlarged schematic diagram at A in the middle;

[0042] Figure 5 This is a schematic diagram of the installation of the ammonia injection mechanism of the present invention;

[0043] Figure 6 It is a schematic cross-sectional view of the flue shell of the present invention.

[0044] In the figure: 1. flue shell; 2. air inlet; 3. air outlet; 4. inspection panel; 5. connecting pipe; 6. ammonia spraying mechanism; 7. sampling controller; 8. guide plate; 9. flow meter; 911. electronic valve; 912. main pipe; 913. guide pipe; 914. spray head; 811. mounting pipe; 812. top shell; 813. first connecting plate; 814. bolts; 815. fixing plate; 816. motor; 817. shaft; 818. stirring blade; 819. second connecting plate; 711. connecting pipe. DETAILED DESCRIPTION

[0045] The following description is merely exemplary in nature and is not intended to limit the present disclosure, application, and use. It should be understood that in all of these figures, the same or similar reference numerals indicate the same or similar parts and features. The various drawings only schematically represent the concepts and principles of the embodiments of the present disclosure, and do not necessarily show the specific dimensions and proportions of the various embodiments of the present disclosure. Specific parts in specific drawings may be exaggerated to illustrate the relevant details or structures of the embodiments of the present disclosure.

[0046] See also Figure 1-6 , an embodiment provided by the present invention:

[0047] A circulating fluidized bed boiler precision ammonia injection control device comprises a flue shell 1, an air inlet 2 is provided at one end of the flue shell 1, and an air outlet 3 is provided at the other end of the flue shell 1, an inspection plate 4 is provided on the outer surface of one side of the flue shell 1, and an ammonia injection mechanism 6 is provided on the inner wall of the flue shell 1, and the ammonia injection mechanism 6 comprises a main pipe 912, and the outer surfaces of both ends of the main pipe 912 are connected to multiple groups of guide pipes 913, and the bottom ends of the multiple groups of guide pipes 913 are connected to multiple groups of spray heads 914, and the top side of the main pipe 912 is connected to a connecting pipe 5, and the connecting pipe 5 passes through the outer surface of the flue shell 1, the outer surface of the connecting pipe 5 is provided with an electronic valve 911, and one end of the connecting pipe 5 is connected to the flow meter 9, and one end of the flow meter 9 is connected to the connecting pipe 711, and the top outer surface of the main pipe 912 is provided with multiple groups of bypass mechanisms, and the bypass mechanisms include a mounting pipe 811, the inner wall of the mounting pipe 811 is fixedly installed with a motor 816, and one end of the motor 816 is connected to a shaft rod 817, and the outer surface of the shaft rod 817 is fixedly installed with multiple groups of stirring blades 818, and the top of the mounting pipe 811 is provided with a top shell 812.

[0048] Furthermore, a heat dissipation groove is provided at the top of the top shell 812, and a first connecting plate 813 is fixedly installed on the outer surface of the top shell 812. The heat dissipation groove design at the top of the top shell 812 helps to dissipate the heat generated by the motor 816 during operation in a timely manner to prevent the motor from overheating, thereby extending the service life of the motor and ensuring the stable operation of the flow bypass mechanism.

[0049] Furthermore, a second connecting plate 819 is fixedly mounted on the outer surface of the top end of the mounting tube 811, and the second connecting plate 819 is connected to the first connecting plate 813 through multiple sets of bolts 814. The detachable connection between the first connecting plate 813 and the second connecting plate 819 and the bolts 814 makes the connection between the top shell 812 and the mounting tube 811 both firm and easy to disassemble. This design facilitates the maintenance and overhaul of the equipment and reduces maintenance costs and time.

[0050] Furthermore, a plurality of guide plates 8 are provided on the inner wall of the flue shell 1, and a plurality of sampling controllers 7 are provided on the top of the plurality of guide plates 8. The plurality of sampling controllers 7 are fixedly connected to the outer surface of one side of the flue shell 1. The guide plates 8 can guide the flow direction of the flue gas so that the flue gas is more evenly distributed in the flue, thereby improving the accuracy and representativeness of the sampling controller 7 in detecting the NOx concentration.

[0051] Furthermore, a filter is installed on the outer surface of the bottom end of the plurality of spray heads 914. The filter is designed to filter out impurities and particulate matter in the ammonia gas, prevent the spray heads from being blocked, and ensure smooth injection and uniform distribution of the ammonia gas.

[0052] Furthermore, one end of the connecting pipe 711 is connected with a flange, and the design of the flange facilitates the connection and disassembly of the pipeline, while also ensuring the sealing and stability of the connection.

[0053] A circulating fluidized bed boiler precise ammonia injection control method comprises the following steps.

[0054] 1. Device connection and preparation:

[0055] 1) Use the flange at one end of the connecting pipe 711 to connect the ammonia spraying mechanism with a feed pipe such as an ammonia water or ammonia gas supply system to ensure a stable supply of ammonia gas.

[0056] 2) Check and confirm that all parts are tightly connected and there is no leakage.

[0057] 3) Start the boiler to allow the flue gas to enter the flue shell 1 through the air inlet.

[0058] 2. Real-time monitoring and data collection

[0059] 1) When the flue gas flows in the flue shell 1, multiple groups of sampling controllers 7 monitor the NOx content in the flue gas in real time.

[0060] 2) The sampling controller transmits the detected NOx concentration data to the control system.

[0061] 3. Calculation and Control:

[0062] 1) The control system calculates the required ammonia injection amount based on the received NOx concentration data.

[0063] 2) By controlling the opening of the electronic valve 911 and the reading of the flow meter, the flow rate of ammonia in the connecting pipe is adjusted to ensure that the amount of ammonia injected into the flue shell matches the concentration of NOx.

[0064] 4. Ammonia injection and mixing:

[0065] 1) After ammonia enters the main pipe 912 through the connecting pipe, it is divided along the main pipe to the multiple groups of guide pipes 913.

[0066] 2) The spray head 914 at the top of the guide pipe 913 sprays the ammonia gas into the flue gas evenly in the form of fine droplets.

[0067] At the same time, the flow bypass mechanism at the top of the main pipe is driven by a motor, which drives the stirring blades to rotate through the shaft, generating airflow to disturb and mix the ammonia and flue gas, thereby improving the mixing efficiency.

[0068] 5. Reaction and Emission

[0069] 1) After precise injection and thorough mixing, ammonia reacts chemically with NOx in the flue gas to generate harmless nitrogen and water vapor.

[0070] 2) The treated flue gas is discharged from the boiler through the outlet.

[0071] 6. Feedback and Adjustment

[0072] 1) During the entire control process, the control system will continuously adjust the opening of the electronic valve and the flow meter reading based on the real-time monitored NOx concentration data and ammonia injection amount feedback.

[0073] 2) Ensure the stability and accuracy of denitrification effect through continuous adjustment and optimization.

[0074] Working principle: First, the ammonia spraying mechanism 6 is connected to the feed pipe (such as ammonia water or ammonia gas supply system) by using the flange at one end of the connecting pipe 711 to ensure a stable supply of ammonia gas.

[0075] During the operation of the boiler, the flue gas enters the flue shell 1 through the air inlet 2 and flows along the inner wall of the flue shell 1. In order to monitor the NOx content in the flue gas in real time, multiple sets of sampling controllers 7 are arranged on the inner wall of the flue shell 1, which can accurately detect the concentration of NOx in the flue gas and transmit the detection data to the control system.

[0076] The control system calculates the required ammonia injection amount according to the NOx concentration data provided by the sampling controller 7, and adjusts the flow rate of ammonia in the connecting pipe 5 by controlling the opening of the electronic valve 911 and the reading of the flow meter 9. In this way, it can ensure that the amount of ammonia injected into the flue shell 1 matches the NOx concentration, and achieve accurate denitration.

[0077] When ammonia enters the main pipe 912 through the connecting pipe 5, it will be diverted along the main pipe 912 to multiple groups of guide pipes 913. In order to enhance the mixing effect of ammonia in the flue gas, a spray head 914 is installed at the top of each group of guide pipes 913, and these spray heads 914 can evenly spray ammonia into the flue gas in the form of fine droplets.

[0078] In addition, in order to improve the mixing efficiency of ammonia and flue gas, multiple groups of flow-around mechanisms are provided on the outer surface of the top of the main pipe 912. These flow-around mechanisms are driven by the motor 816, and the stirring blades 818 are driven to rotate through the shaft 817. The rotation of the stirring blades 818 generates airflow, disturbs and mixes the ammonia and flue gas, thereby achieving a more uniform flow-around effect.

[0079] After precise injection and full mixing, ammonia reacts chemically with NOx in the flue gas to generate harmless nitrogen and water vapor. Finally, the treated flue gas is discharged from the boiler through the outlet 3.

[0080] During the entire control process, the control system will continuously adjust the opening of the electronic valve 911 and the reading of the flow meter 9 according to the real-time monitored NOx concentration data and the ammonia injection amount feedback to ensure the stability and accuracy of the denitrification effect.

[0081] It will be apparent to those skilled in the art that the invention is not limited to the details of the exemplary embodiments described above and that the invention can be implemented in other specific forms without departing from the spirit or essential features of the invention. Therefore, the embodiments should be considered exemplary and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description, and it is intended that all variations falling within the meaning and scope of the equivalent elements of the claims be included in the invention. Any reference numeral in a claim should not be considered as limiting the claim to which it relates.

Claims

1. A circulating fluidized bed boiler precise ammonia injection control device, comprising a flue shell (1), one end of the flue shell (1) is provided with an air inlet (2), and the other end of the flue shell (1) is provided with an air outlet (3), and an inspection plate (4) is provided on one side of the outer surface of the flue shell (1), characterized in that: The inner wall of the flue shell (1) is provided with an ammonia spraying mechanism (6), the ammonia spraying mechanism (6) comprises a main pipe (912), and the outer surfaces of both ends of the main pipe (912) are connected to multiple groups of flow guide pipes (913), and the bottom ends of the multiple groups of flow guide pipes (913) are connected to multiple groups of spray heads (914), the top side of the main pipe (912) is connected to a connecting pipe (5), and the connecting pipe (5) passes through the outer surface of the flue shell (1), the outer surface of the connecting pipe (5) is provided with an electronic valve (911), and the connecting pipe (5) is connected to the bottom end of the connecting pipe (913). One end is connected to a flow meter (9), one end of the flow meter (9) is connected to a connecting pipe (711), a plurality of flow bypass mechanisms are arranged on the outer surface of the top end of the main pipe (912), and the flow bypass mechanisms include a mounting pipe (811), a motor (816) is fixedly mounted on the inner wall of the mounting pipe (811), and a shaft (817) is connected to one end of the motor (816), a plurality of stirring blades (818) are fixedly mounted on the outer surface of the shaft (817), and a top shell (812) is arranged on the top end of the mounting pipe (811).

2. The circulating fluidized bed boiler precise ammonia injection control device according to claim 1, characterized in that: A heat dissipation groove is provided at the top of the top shell (812), and a first connecting plate (813) is fixedly mounted on the outer surface of the top shell (812).

3. The circulating fluidized bed boiler precise ammonia injection control device according to claim 1, characterized in that: A second connecting plate (819) is fixedly mounted on the outer surface of the top end of the mounting tube (811), and the second connecting plate (819) is connected to the first connecting plate (813) via a plurality of sets of bolts (814).

4. The circulating fluidized bed boiler precise ammonia injection control device according to claim 1, characterized in that: The inner wall of the flue shell (1) is provided with a plurality of groups of guide plates (8), and the tops of the plurality of groups of guide plates (8) are provided with a plurality of groups of sampling controllers (7), and the plurality of groups of sampling controllers (7) are fixedly connected to the outer surface of one side of the flue shell (1).

5. The circulating fluidized bed boiler precise ammonia injection control device according to claim 1, characterized in that: The outer surfaces of the bottom ends of the plurality of groups of spray heads (914) are provided with filter screens.

6. The circulating fluidized bed boiler precise ammonia injection control device according to claim 1, characterized in that: One end of the connecting pipe (711) is connected with a flange.

7. A circulating fluidized bed boiler precise ammonia injection control method, characterized by: The following steps are involved:

1. Device connection and preparation: 1) The ammonia spraying mechanism is connected to a feed pipe (such as an ammonia water or ammonia gas supply system) using a flange at one end of the connecting pipe (711) to ensure a stable supply of ammonia gas. 2) Check and confirm that all parts are tightly connected and there is no leakage. 3) Start the boiler to allow the flue gas to enter the flue shell (1) through the air inlet.

2. Real-time monitoring and data collection 1) When the flue gas flows in the flue shell (1), multiple groups of sampling controllers (7) monitor the NOx content in the flue gas in real time. 2) The sampling controller transmits the detected NOx concentration data to the control system.

3. Calculation and Control: 1) The control system calculates the required ammonia injection amount based on the received NOx concentration data. 2) By controlling the opening of the electronic valve (911) and the reading of the flow meter, the flow rate of ammonia in the connecting pipe is adjusted to ensure that the amount of ammonia injected into the flue shell matches the concentration of NOx.

4. Ammonia injection and mixing: 1) After ammonia enters the main pipe (912) through the connecting pipe, it is divided along the main pipe to multiple groups of guide pipes (913). 2) The spray head (914) at the top of the guide pipe (913) sprays ammonia gas into the flue gas evenly in the form of fine droplets. At the same time, the flow bypass mechanism at the top of the main pipe is driven by a motor, which drives the stirring blades to rotate through the shaft, generating airflow to disturb and mix the ammonia and flue gas, thereby improving the mixing efficiency.

5. Reaction and Emission 1) After precise injection and thorough mixing, ammonia reacts chemically with NOx in the flue gas to generate harmless nitrogen and water vapor. 2) The treated flue gas is discharged from the boiler through the outlet.

6. Feedback and Adjustment 1) During the entire control process, the control system will continuously adjust the opening of the electronic valve and the flow meter reading based on the real-time monitored NOx concentration data and ammonia injection amount feedback. 2) Ensure the stability and accuracy of denitrification effect through continuous adjustment and optimization.

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