Denitration ammonia spraying control system
By installing an ammonia injection grid and a monitoring regulating valve inside the flue pipe, the ammonia flow rate can be precisely controlled, solving the problems of substandard nitrogen oxide emissions and equipment corrosion in existing denitrification ammonia injection systems, and achieving more efficient nitrogen oxide emission reduction and equipment protection.
Patent Information
- Application Number
- CN202422934158.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-11-29
- Publication Date
- 2025-12-02
- Estimated Expiration
- 2034-11-29
AI Technical Summary
Existing denitrification ammonia injection systems are prone to over- or under-injection when controlling the amount of ammonia injected, leading to increased ammonia consumption, ammonia escape, and equipment corrosion, and they cannot effectively control nitrogen oxide emissions.
An ammonia injection grid is installed inside the flue gas pipe to divide it into two channels. By combining the first and second monitoring devices with the regulating valve, the ammonia emission is precisely controlled by monitoring the concentration of nitrogen oxides and the ammonia flow rate in the flue gas. The ammonia mixing ratio is optimized by using the evaporator and dilution pipe.
It achieves more accurate ammonia flow control, reduces nitrogen oxide emissions, lowers ammonia consumption and equipment corrosion risk, and improves the economic efficiency of equipment operation.
Smart Images
Figure CN223615686U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to a denitrification ammonia injection control system, belonging to the field of flue gas treatment technology. Background Technology
[0002] In actual production, excessive ammonia injection in the selective catalytic reduction (SCR) denitrification ammonia injection control system of thermal power plants not only increases ammonia consumption and thus operating costs, but also leads to the generation of large amounts of viscous ammonium bisulfate (ABS) due to increased ammonia escape, causing ash accumulation and corrosion damage at the cold end of the air preheater, and significantly reducing the economic performance of the unit. Conversely, insufficient ammonia injection results in substandard nitrogen oxide (NOx) emissions at the outlet.
[0003] In order to ensure that the denitrification system meets emission standards, operators of existing denitrification ammonia injection systems may use excessive ammonia injection. This not only increases ammonia consumption but may also lead to ammonia escape, thereby affecting the normal operation of downstream equipment.
[0004] In view of this, it is indeed necessary to improve the existing denitrification ammonia injection control system to solve the above problems. Utility Model Content
[0005] To address the aforementioned technical problems, this utility model provides a denitrification ammonia injection control system, which can more accurately control the ammonia flow rate and reduce nitrogen oxide emissions.
[0006] The technical solution of this utility model is:
[0007] A denitrification ammonia injection control system for a coal-fired power plant, comprising:
[0008] Boiler with an external exhaust pipe;
[0009] An SCR reactor, connected to the exhaust pipe, is used to treat and discharge flue gas;
[0010] An ammonia storage tank is externally connected to an ammonia injection pipe that is connected to the exhaust pipe. The ammonia injection pipe is equipped with a regulating valve, which is used to regulate the flow rate of ammonia gas in the ammonia injection pipe.
[0011] The exhaust pipe is equipped with an ammonia injection grid connected to the ammonia injection pipe. The ammonia injection grid divides the exhaust pipe into a first flue gas channel and a second flue gas channel. The flue gas and the ammonia gas are mixed in the second flue gas channel and discharged after passing through the SCR reactor located in the second flue gas channel. The first flue gas channel is also equipped with a first monitoring device. The regulating valve is electrically connected to the first monitoring device to adjust the ammonia gas emission rate according to the concentration of nitrogen oxides in the flue gas monitored by the first monitoring device.
[0012] As a further improvement of this utility model, the ammonia injection pipe includes a first ammonia injection pipe and a second ammonia injection pipe, and an evaporator is provided between the first ammonia injection pipe and the second ammonia injection pipe. The evaporator is configured to evaporate the ammonia water flowing into the ammonia storage tank from the first ammonia injection pipe into ammonia gas, and output it to the second ammonia injection pipe and then discharge it into the flue pipe.
[0013] As a further improvement of this utility model, the second ammonia injection pipe is also provided with a second monitoring element, and the regulating valve is located between the second monitoring element and the ammonia injection grid. The second monitoring element is configured to monitor the flow rate of ammonia gas in the second ammonia injection pipe.
[0014] As a further improvement of this utility model, an external gas supply pipe is connected between the regulating valve and the second monitoring element. The gas supply pipe supplies air to dilute the ammonia gas in the second ammonia injection pipe.
[0015] As a further improvement of this utility model, the gas transmission pipe is provided with a control valve, which is electrically connected to the first monitoring element and can control the opening or closing or flow rate of the gas transmission pipe according to the concentration of nitrogen oxides in the flue gas detected by the first monitoring element.
[0016] As a further improvement of this utility model, the first monitoring device monitors the concentration of nitrogen oxides in the flue gas and sends a first signal, the second monitoring device monitors the flow rate of ammonia in the second ammonia injection pipe and sends a second signal, and the denitrification ammonia injection control system is also provided with a load monitor, the load monitor receives the first signal and the second signal and sends a third signal, the third signal can be selectively transmitted to an external display.
[0017] As a further improvement of this utility model, the denitrification ammonia spraying control system is also provided with an alarm device, which is configured to receive the third signal and issue an alarm based on the value of the third signal.
[0018] As a further improvement of this utility model, the concentration of nitrogen oxides in the flue gas detected by the first monitoring device is directly proportional to the air flow rate in the gas transmission pipe.
[0019] As a further improvement of this utility model, the concentration of nitrogen oxides in the flue gas detected by the first monitoring device is directly proportional to the flow rate of ammonia in the ammonia injection pipe.
[0020] The beneficial technical effects of this utility model are as follows: by setting an ammonia injection grid connected to the ammonia injection pipe in the flue pipe, the flue pipe is divided into a first flue gas channel and a second flue gas channel. Flue gas and ammonia are mixed in the second flue gas channel and discharged after passing through the SCR reactor located in the second flue gas channel. By setting a first monitoring element electrically connected to the regulating valve on the first flue gas channel, the ammonia emission rate can be adjusted according to the concentration of nitrogen oxides in the flue gas monitored by the first monitoring element. This allows for more accurate control of the ammonia flow rate and reduces nitrogen oxide emissions. Attached Figure Description
[0021] Figure 1 This is a system diagram of a denitrification ammonia spraying control system conforming to a preferred embodiment of the present utility model. Detailed Implementation
[0022] In order to better understand the technical means of this utility model and to implement it in accordance with the contents of the specification, the specific embodiments of this utility model will be further described in detail below with reference to the accompanying drawings and examples. The following examples are used to illustrate this utility model, but are not intended to limit the scope of this utility model.
[0023] Please see Figure 1 As shown, this utility model discloses a denitrification ammonia injection control system 100 for use in a coal-fired power plant, including a boiler 1, an SCR reactor 2, and an ammonia storage tank 3. The boiler 1 is externally connected to a flue gas pipe 11, and the SCR reactor 2 is connected to the flue gas pipe 11 for treating and discharging flue gas. The ammonia storage tank 3 is externally connected to an ammonia injection pipe 31 connected to the flue gas pipe 11. The flue gas discharged from the boiler 1 and the ammonia gas injected from the ammonia storage tank 3 mix in the flue gas pipe 11 and are discharged after being treated by the SCR reactor 2, reducing nitrogen oxide emissions and protecting the ecological environment. Preferably, the concentration of nitrogen oxides in the flue gas monitored by the first monitoring element 6 is directly proportional to the flow rate of ammonia gas in the ammonia injection pipe 31.
[0024] The exhaust pipe 11 is equipped with an ammonia injection grid 4 connected to the ammonia injection pipe 31. The ammonia injection grid 4 divides the exhaust pipe 11 into a first flue gas channel 111 and a second flue gas channel 112. The flue gas and the ammonia gas mix in the second flue gas channel 112 and are discharged after passing through the SCR reactor 2 located in the second flue gas channel 112. In other words, the flue gas mixes with the ammonia gas after passing through the ammonia injection grid 4.
[0025] Preferably, the ammonia injection pipe 31 is equipped with a regulating valve 5, which is used to regulate the flow rate of the ammonia gas. A first monitoring element 6 is correspondingly provided on the first flue gas passage 111, and the regulating valve 5 is electrically connected to the first monitoring element 6 to adjust the ammonia emission rate according to the concentration of nitrogen oxides in the flue gas monitored by the first monitoring element 6. This ensures that the mixing ratio of the flue gas and the ammonia gas is within a preset range.
[0026] The ammonia injection pipe 31 includes a first ammonia injection pipe 311 and a second ammonia injection pipe 312, and an evaporator 313 is provided between the first ammonia injection pipe 311 and the second ammonia injection pipe 312. The evaporator 313 is configured to evaporate the ammonia water flowing into the ammonia storage tank 3 from the first ammonia injection pipe 311 into ammonia gas, and output it to the second ammonia injection pipe 312 before being discharged into the flue gas pipe 11. An isolation valve may also be provided on the first ammonia injection pipe 311, which is used to control the opening and closing of the first ammonia injection pipe 311.
[0027] The second ammonia injection pipe 312 is also equipped with a second monitoring element 7. The regulating valve 5 is located between the second monitoring element 7 and the ammonia injection grid 4. The second monitoring element 7 is configured to monitor the flow rate of ammonia gas in the second ammonia injection pipe 312. Therefore, by monitoring the real-time flow rate of ammonia gas in the second ammonia injection pipe 312, the flow rate of ammonia gas can be adjusted according to the concentration of nitrogen oxides in the flue gas monitored by the first monitoring element 6.
[0028] An external gas supply pipe 8 is connected between the regulating valve 5 and the second monitoring element 7. The gas supply pipe 8 allows air to circulate, thereby diluting the ammonia gas in the second ammonia injection pipe 312. Preferably, a third monitoring element is also provided between the second monitoring element 7 and the regulating valve 5. The third monitoring element is used to monitor the concentration of the diluted ammonia gas.
[0029] The gas supply pipe 8 is equipped with a control valve, which is electrically connected to the first monitoring element 6 and can control the opening and closing or flow rate of the gas supply pipe 8 according to the concentration of nitrogen oxides in the flue gas detected by the first monitoring element 6. Preferably, the concentration of nitrogen oxides in the flue gas detected by the first monitoring element 6 is proportional to the flow rate of air in the gas supply pipe.
[0030] In this embodiment, the first monitoring element 6 monitors the concentration of nitrogen oxides in the flue gas and sends a first signal, the second monitoring element 7 monitors the flow rate of ammonia in the second ammonia injection pipe and sends a second signal, and the denitrification ammonia injection control system 100 is also provided with a load monitor 9, which receives the first signal and the second signal and sends a third signal, which can be selectively transmitted to an external display 10.
[0031] In other words, the control valve, the regulating valve 5, the first monitoring element 6, and the load monitor 9 are interconnected. The control valve controls the concentration of ammonia gas to match the concentration of nitrogen oxides in the flue gas detected by the first monitoring element 6, and mixes them in a preset ratio. At this time, the regulating valve 5 can control the flow rate of the ammonia gas to ensure the load. The denitrification ammonia injection control system 100 is also equipped with an alarm device, which is configured to receive the third signal and issue an alarm based on the value of the third signal. When the load detected by the load monitor 9 is high enough, an alarm will be issued through the alarm device for real-time adjustment. The alarm device can also be connected to an external display for easy observation by staff.
[0032] In summary, the denitrification ammonia injection control system 100 of this utility model divides the exhaust pipe 11 into a first flue gas channel 111 and a second flue gas channel 112 by setting an ammonia injection grid 4 connected to the ammonia injection pipe 31 in the exhaust pipe 11. The flue gas and ammonia are mixed in the second flue gas channel 112 and discharged after passing through the SCR reactor 2 located in the second flue gas channel 112. By setting a first monitoring element 6 electrically connected to the regulating valve 5 on the first flue gas channel 111, the ammonia emission rate can be adjusted according to the concentration of nitrogen oxides in the flue gas monitored by the first monitoring element 6. This allows for more accurate control of the ammonia flow rate and reduces nitrogen oxide emissions.
[0033] The above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present utility model, and these improvements and modifications should also be considered within the protection scope of the present utility model.
Claims
1. A denitrification ammonia injection control system for use in coal-fired power plants, characterized in that, include: Boiler with an external exhaust pipe; An SCR reactor, connected to the exhaust pipe, is used to treat and discharge flue gas; An ammonia storage tank is externally connected to an ammonia injection pipe that is connected to the exhaust pipe. The ammonia injection pipe is equipped with a regulating valve, which is used to regulate the flow rate of ammonia gas in the ammonia injection pipe. The exhaust pipe is equipped with an ammonia injection grid connected to the ammonia injection pipe. The ammonia injection grid divides the exhaust pipe into a first flue gas channel and a second flue gas channel. The flue gas and the ammonia gas are mixed in the second flue gas channel and discharged after passing through the SCR reactor located in the second flue gas channel. The first flue gas channel is also equipped with a first monitoring device. The regulating valve is electrically connected to the first monitoring device to adjust the ammonia gas emission rate according to the concentration of nitrogen oxides in the flue gas monitored by the first monitoring device.
2. The denitrification ammonia injection control system according to claim 1, characterized in that, The ammonia injection pipe includes a first ammonia injection pipe and a second ammonia injection pipe, and an evaporator is provided between the first ammonia injection pipe and the second ammonia injection pipe. The evaporator is configured to evaporate the ammonia water flowing into the ammonia storage tank from the first ammonia injection pipe into ammonia gas, and then output it to the second ammonia injection pipe and discharge it into the flue pipe.
3. The denitrification ammonia injection control system according to claim 2, characterized in that, The second ammonia injection pipe is also equipped with a second monitoring element, and the regulating valve is located between the second monitoring element and the ammonia injection grid. The second monitoring element is configured to monitor the flow rate of ammonia gas in the second ammonia injection pipe.
4. The denitrification ammonia injection control system according to claim 3, characterized in that, An external gas supply pipe is also connected between the regulating valve and the second monitoring element. The gas supply pipe allows air to circulate in order to dilute the ammonia gas in the second ammonia injection pipe.
5. The denitrification ammonia injection control system according to claim 4, characterized in that, The gas pipeline is equipped with a control valve, which is electrically connected to the first monitoring device and can control the opening or closing of the gas pipeline or the flow rate according to the concentration of nitrogen oxides in the flue gas detected by the first monitoring device.
6. The denitrification ammonia injection control system according to claim 3, characterized in that, The first monitoring device monitors the concentration of nitrogen oxides in the flue gas and sends a first signal. The second monitoring device monitors the flow rate of ammonia in the second ammonia injection pipe and sends a second signal. The denitrification ammonia injection control system is also equipped with a load monitor. The load monitor receives the first signal and the second signal and sends a third signal. The third signal can be selectively transmitted to an external display.
7. The ammonia injection control system for denitrification according to claim 6, characterized in that, The denitrification ammonia spraying control system is also equipped with an alarm device, which is configured to receive the third signal and issue an alarm based on the value of the third signal.
8. The denitrification ammonia injection control system according to claim 5, characterized in that, The concentration of nitrogen oxides in the flue gas detected by the first monitoring device is directly proportional to the air flow rate in the gas transmission pipe.
9. The denitrification ammonia injection control system according to claim 1, characterized in that, The concentration of nitrogen oxides in the flue gas detected by the first monitoring device is directly proportional to the flow rate of ammonia in the ammonia injection pipe.