A kind of ammonia injection system for gas turbine SCR denitration

Abstract

The present application relates to flue gas denitration technical field, specifically for a kind of ammonia injection system suitable for gas turbine SCR denitration;The system can be adjusted liquid ammonia vaporization quantity in real time according to the NOx content in flue gas emission, adopt two heat exchangers in series, use workshop low-quality steam as liquid nitrogen vaporization heat source, steam becomes hot water after heat exchange through post heat exchanger, then becomes normal temperature water after heat exchange through pre heat exchanger, maximum limit all heat in steam is utilized, temperature and steam consumption self-control operation are equipped at heat exchanger tube pass outlet, ensure that ammonia gas does not carry liquid, ensure the accuracy of rear flowmeter, post heat exchanger is selected vertical tube heat exchanger, bottom tube pass inlet head is equipped with liquid level meter monitoring not easy vaporization medium and timely discharge, ammonia gas on-line analyzer is equipped in airtight room, if there is leakage, liquid ammonia and ammonia gas supply are directly cut off;Solved the problem that a large amount of energy is needed to decompose urea into ammonia gas in the prior art, and there is a safety hazard.

Description

Technical Field

[0001] This invention relates to the field of flue gas denitrification technology, specifically to an ammonia injection system for SCR denitrification in gas turbines. Background Technology

[0002] Gas turbines are widely used in power plants. During actual operation, nitrogen and oxygen in the air react in a high-temperature, high-pressure combustion chamber to generate nitrogen oxides, which are then emitted into the atmosphere along with the flue gas. Selective catalytic reduction (SCR) is a common nitrogen oxide waste gas treatment technology. Its principle is to catalytically reduce nitrogen oxides and a reducing agent into nitrogen and water under the action of a catalyst. It is often used in flue gas emission treatment systems in power plants, steel plants, chemical plants, and other workshops. In the application of SCR denitrification technology, the ammonia preparation system provides the reducing agent for the selective catalytic reduction reaction and is an indispensable part. Common methods for ammonia preparation in SCR denitrification technology include liquid ammonia vaporization, ammonia water vaporization, urea hydrolysis, or pyrolysis.

[0003] Chinese patent CN116588950A discloses a method for converting liquid ammonia into urea as a reducing agent in SCR flue gas denitrification of coal-fired power generation units. This invention involves dissolving dry urea granules in a dissolving tank via pneumatic conveying or manual unpacking, and then injecting the solution into a urea solution storage tank via a dissolving pump. The urea solution in the storage tank is then pumped into another urea solution storage tank via a transfer pump. The urea solution in the storage tank is then pumped to a pyrolysis furnace or hydrolysis reactor, where it decomposes to produce an ammonia-containing mixed gas that enters the SCR ammonia injection system. This invention eliminates the use of liquid ammonia at the source, thus completely eliminating the safety hazards associated with the use of liquid ammonia. However, the decomposition of urea into ammonia requires a large amount of energy and may even require the addition of a catalyst. The investment cost and operating energy consumption are far higher than other ammonia production methods. In addition, the decomposition of urea produces cyanic acid, which is extremely acidic and corrodes equipment and pipelines, and may even cause equipment thinning and leakage, creating safety hazards. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention provides a gas turbine SCR denitrification ammonia injection system, which solves the problems of requiring a large amount of energy and posing safety hazards in the existing technology of decomposing urea into ammonia.

[0005] To achieve the above objectives, the present invention provides the following technical solution:

[0006] An ammonia injection system for SCR denitrification in gas turbines, comprising:

[0007] A liquid ammonia injection module, wherein the liquid ammonia injection module is used to output liquid ammonia gas to the vaporization module with controllable flow rate;

[0008] A liquid ammonia vaporization module is used to vaporize liquid ammonia by exchanging heat with steam, and to adjust the liquid ammonia flow rate according to feedback from the vacuum regulation module.

[0009] A vacuum regulation module is used to detect the temperature, pressure, density and flow rate of ammonia, and to adjust the vacuum level of ammonia to a certain value before outputting it to the pressure regulation module.

[0010] A pressure regulating module is used to inject compressed air into ammonia to regulate the pressure of the mixed gas to a predetermined range before outputting it to the ammonia output module.

[0011] An ammonia output module is used to detect and control the pressure and flow rate of ammonia output.

[0012] Preferably, the liquid ammonia injection module includes several liquid ammonia cylinders, each with an electronic scale for weighing at its bottom. A first angle valve is installed at the outlet of each cylinder. Several second angle valves are installed between the first angle valves. Several third angle valves are also installed between the first angle valves and connected in parallel with the second angle valves. An injector a is installed on the pipeline between the several third angle valves. A manual valve a and a local pressure gauge a are sequentially installed between the injector a and the pipeline between the injector a and the several third angle valves. A manual valve c is installed at the outlet of the injector a.

[0013] Preferably, the liquid ammonia vaporization module includes a heat exchanger a connected to a plurality of second angle valves via pipelines. A shut-off valve a and a control valve a are sequentially arranged between the heat exchanger a and the plurality of second angle valves. A heat exchanger b is provided at the shell-side outlet of the heat exchanger a via a tube-side inlet connected thereto. A shut-off valve b is provided at the shell-side inlet of the heat exchanger b. The shell-side outlet of the heat exchanger b is connected to the tube-side inlet of the heat exchanger a via a pipeline. A control valve b and a steam trap a are provided at the tube-side outlet of the heat exchanger a. A control valve d and a check valve a are sequentially arranged at the bottom of the heat exchanger b. A remote level gauge a is provided at the bottom end cap of the tube side of the heat exchanger b.

[0014] Preferably, the vacuum regulation module includes a vacuum regulator installed at the outlet of the tube side of heat exchanger b. A safety valve a, a remote thermometer a, and a remote pressure gauge a are sequentially installed between the tube side of heat exchanger b and the vacuum regulator. The outlet of safety valve a is connected to the ammonia absorption system. A control valve c is installed on the branch pipeline between the remote pressure gauge a and the vacuum regulator, which is connected to the ammonia absorption system. A remote flow meter a is installed at the outlet of the vacuum regulator. A remote pressure gauge b, a density meter a, and a remote thermometer b are sequentially installed on the pipeline between the vacuum regulator and the remote flow meter a. An online NOx analyzer is installed on the remote flow meter a.

[0015] Preferably, there are several ammonia output modules. Each ammonia output module includes an injector b connected to a remote flow meter a via a pipeline. A control valve e, a remote flow meter b, and a remote pressure gauge c are sequentially installed on the pipeline between the remote flow meter a and the injector b. A manual valve d is installed on the outlet pipeline of the injector b.

[0016] Preferably, the pressure regulating module includes a hand valve e, a check valve b, and a hand valve b arranged sequentially on the inlet pipeline of injector a. A local pressure gauge b, a control valve f, and a remote pressure gauge d are arranged sequentially on the pipeline between the check valve b and the injector b.

[0017] Preferably, the system also includes several ammonia analyzers for detecting the concentration of ammonia in the environment, an electric alligator clamp actuator a is provided at the outlet of the liquid ammonia cylinder, and an emergency stop button that controls the interlocking and closing of the electric alligator clamp actuator a, shut-off valve a, shut-off valve b and control valve e according to the ammonia analyzer values.

[0018] Compared with the prior art, the present invention provides a gas turbine SCR denitrification ammonia injection system with the following advantages:

[0019] The beneficial effects of this invention are:

[0020] 1. This SCR denitrification ammonia injection system has low operating costs, extremely high safety factor, small footprint, and can realize automated control during the use of ammonia. It can adjust the amount of liquid ammonia vaporization in real time according to the NOx content in the flue gas emission, while avoiding excessive ammonia injection that would cause ammonia escape to exceed the design value of the SCR catalyst.

[0021] 2. Liquid ammonia vaporization employs two heat exchangers connected in series, using low-quality steam from the workshop as the heat source for liquid nitrogen vaporization. The steam first passes through the downstream heat exchanger to become hot water, and then passes through the upstream heat exchanger to become room temperature water, maximizing the utilization of all the heat in the steam. The tube-side outlet of the heat exchangers is equipped with automatic temperature and steam consumption control to ensure that the ammonia does not carry liquid and to guarantee the accuracy of the downstream flow meter. The downstream heat exchanger is a vertical shell-and-tube heat exchanger, and the bottom tube-side inlet end cap is equipped with a level gauge to monitor non-vaporizable media and discharge them in a timely manner to avoid accumulation and blockage.

[0022] 3. When the ammonia injector is put into operation with compressed air, the vacuum regulator will automatically open only when a certain vacuum level is reached. In other states, it will be in a closed circuit state to ensure the safety of negative pressure operation. When the absolute pressure gauge on the ammonia pipeline connected to the ammonia injector is 40-60 kPa(A) higher than the set value, the control valve of the compressed air connected to the ammonia injector will be controlled to increase the compressed air volume and ensure that the absolute pressure gauge is at the set value. When the absolute pressure gauge is higher than 90-110 kPa(A), the ammonia control valve on the corresponding injector will be interlocked to prevent flue gas and air from being drawn back into the system and to ensure that other ammonia injections are in normal operating condition. At this time, the system will recalculate the flow rate of the other two ammonia lines to ensure that the total amount of ammonia injected in real time meets the denitrification calculation requirements and avoid unqualified flue gas emissions.

[0023] 4. The entire system is set up in a sealed, independent room. Three online ammonia analyzers are installed in the upper part of the room. When any one of the three ammonia analyzers reaches 10-20 ppm in real time, the entire system is interlocked to cut off the supply of liquid ammonia and ammonia gas, which can effectively prevent the escalation of ammonia gas and liquid ammonia leakage accidents and reduce the harm of ammonia gas to the environment and personnel.

[0024] 5. The number of liquid ammonia cylinders and ammonia injectors and their supporting facilities in the entire system can be mechanically increased or decreased based on the actual ammonia demand and liquid ammonia reserve of SCR denitrification, but the net weight of liquid ammonia storage cannot exceed 10 tons, otherwise it will be defined as a major hazard source, resulting in increased investment costs.

[0025] 6. Compared with urea pyrolysis (hydrolysis) and direct ammonia injection methods, this SCR denitrification ammonia injection system is particularly suitable for SCR denitrification of gas turbine flue gas. Urea pyrolysis produces impurities such as ammonium carbamate, cyanuric acid and its polymers. The trace amounts of inorganic salts in the ammonia water can clog the SCR catalyst. Over time, this can lead to a decrease in catalyst activity and failure to meet NOx emission standards. In addition, it can also cause an increase in the exhaust pressure differential of the gas turbine, increasing the risk of gas turbine tripping. Attached Figure Description

[0026] The accompanying drawings, which are included to provide a further understanding of this application and form part of this application, illustrate exemplary embodiments and are used to explain this application, but do not constitute an undue limitation of this application. In the drawings:

[0027] Figure 1 This is a structural block diagram of the SCR denitrification ammonia injection system of the present invention;

[0028] Figure 2 This is a schematic diagram of the liquid ammonia injection module, liquid ammonia vaporization module, and vacuum regulation module of the present invention;

[0029] Figure 3This is a schematic diagram of the pressure regulating module and the ammonia output module of the present invention;

[0030] Figure 4 This is a schematic diagram of the ammonia analyzer of the present invention.

[0031] In the diagram: 1. Liquid ammonia injection module; 11. Liquid ammonia cylinder; 12. Electronic scale; 13. First angle valve; 14. Second angle valve; 15. Third angle valve; 16. Injector a; 17. Manual valve a; 18. Local pressure gauge a; 19. Manual valve c; 2. Liquid ammonia vaporization module; 21. Heat exchanger a; 22. Shut-off valve a; 23. Control valve a; 24. Heat exchanger b; 25. Shut-off valve b; 26. Control valve b; 27. Steam trap a; 28. Control valve d; 29. ​​Check valve a; 30. Remote level gauge a; 3. Vacuum regulation module; 31. Vacuum regulator; 32. Safety valve a; 33. Remote thermometer a; 34. Remote pressure gauge a; 35. Control valve c; 36. Remote flow meter a; 37. Remote pressure gauge b; 38. Density meter a; 39. Remote thermometer b; 40. NOx online analyzer; 4. Pressure regulating module; 41. Manual valve e; 42. Check valve b; 43. Manual valve b; 44. Local pressure gauge b; 45. Control valve f; 46. Remote pressure gauge d; 5. Ammonia output module; 51. Injector b; 52. Control valve e; 53. Remote flow meter b; 54. Remote pressure gauge c; 55. Manual valve d; 61. Ammonia analyzer; 62. Electric alligator clamp actuator a; 63. Emergency stop button. Detailed Implementation

[0032] The following will describe in detail the implementation of this application with reference to the accompanying drawings and embodiments, so that the implementation process of how this application uses technical means to solve technical problems and achieve technical effects can be fully understood and implemented accordingly.

[0033] To address the issues of high energy consumption and safety hazards associated with the existing technology of decomposing urea into ammonia, this invention provides an ammonia injection system suitable for SCR denitrification in gas turbines. This system uses liquid ammonia as the raw material for ammonia generation and incorporates a liquid ammonia vaporization method to improve overall equipment safety and reduce energy consumption. The system includes:

[0034] The liquid ammonia injection module 1 is used to controllably output liquid ammonia to the vaporization module 2; the liquid ammonia vaporization module 2 is used to vaporize liquid ammonia by heat exchange with steam, and adjust the liquid ammonia flow rate according to the feedback of the vacuum regulation module 3; the vacuum regulation module 3 is used to detect the temperature, pressure, density and flow rate of ammonia, and adjust the vacuum degree of ammonia to a certain value before outputting it to the pressure regulation module 4; the pressure regulation module 4 is used to inject compressed air into ammonia to adjust the pressure of the mixed gas to a predetermined range before outputting it to the ammonia output module 5; the ammonia output module 5 is used to detect and control the pressure and flow rate of ammonia output. By using liquid ammonia as raw material, the vacuum regulation module 3 and the pressure regulation module 4 adjust the parameters such as the flow rate, density and pressure of liquid ammonia to adapt to the flow rate of nitrogen oxides to be reduced, thereby realizing the function of catalytic reduction. The whole process does not produce highly acidic substances such as cyanic acid, avoids corrosion of equipment and pipelines, reduces safety hazards, and requires relatively less energy to vaporize ammonia.

[0035] A small amount of ammonia gas is also present in the liquid ammonia. When replacing the liquid ammonia cylinder 11, it is necessary to extract the liquid ammonia from the relevant pipelines to prevent leakage. This vaporized ammonia gas is then collected or treated by acid washing or other methods. The liquid ammonia injection module 1 includes several liquid ammonia cylinders 11. An electronic scale 12 for weighing is installed at the bottom of each liquid ammonia cylinder 11. A first angle valve 13 is installed at the outlet of each liquid ammonia cylinder 11. Several second angle valves 14 are installed between the several first angle valves 13. Furthermore, there are also... A number of third angle valves 15 are connected in parallel with the second angle valve 14. An injector a16 is installed on the pipeline between the number of third angle valves 15. A hand valve a17 and a local pressure gauge a18 are installed sequentially between the injector a16 and the number of third angle valves 15. A hand valve c19 is installed at the outlet of the injector a16. Ammonia gas is collected through the injector a16. The local pressure gauge a18 is generally an absolute pressure gauge with a range of 0 to 1.0 MPa (A) to meet the requirements.

[0036] There are various devices for vaporizing liquid ammonia. Here, low-pressure steam from the workshop is used as the heat source to maximize energy savings. The liquid ammonia vaporization module 2 includes a heat exchanger a21 connected to a pipeline between several second angle valves 14. A shut-off valve a22 and a control valve a23 are sequentially installed between the heat exchanger a21 and the pipeline between the second angle valves 14. A heat exchanger b24 is connected to the shell-side outlet of heat exchanger a21 via a tube-side inlet. A shut-off valve b25 is installed at the shell-side inlet of heat exchanger b24. The shell-side inlet of heat exchanger b24 is connected to the workshop's low-pressure steam pipeline. The pressure of the low-pressure steam can be set to 0.35 MPa(g), and the temperature can be set to 140℃. The shell-side outlet of heat exchanger b24 is connected to the tube-side inlet of heat exchanger a21 via a pipeline. A control valve b26 and a steam trap a27 are installed at the tube-side outlet of heat exchanger a21. The tube-side outlet of heat exchanger A21 is connected to the workshop's steam condensate pipeline network via a pipeline. Control valve D28 and check valve A29 are sequentially installed at the bottom of heat exchanger B24, and it is connected to the ammonia absorption system. A remote level gauge A30 is installed on the bottom end cap of the tube-side of heat exchanger B24. Liquid ammonia vaporization uses two heat exchangers in series, employing low-quality steam from the workshop as the heat source for liquid nitrogen vaporization. The steam first passes through heat exchanger B24 to become hot water, and then through heat exchanger A21 to become room-temperature water, maximizing the utilization of all heat in the steam. The tube-side outlet of heat exchanger B24 is equipped with automatic temperature and steam consumption control to ensure that the ammonia does not carry liquid and to guarantee the accuracy of various downstream flow meters. It is best to select a vertical tube-and-shell heat exchanger for heat exchanger B24, and the bottom tube-side inlet end cap is equipped with a remote level gauge A30 to monitor non-vaporizable media, allowing for timely discharge of such media and preventing accumulation and blockage.

[0037] To achieve the vacuum regulation function of vacuum regulation module 3, the following structure of vacuum regulation module 3 is provided. Vacuum regulation module 3 includes a vacuum regulator 31 installed at the outlet of the tube side of heat exchanger b24. A safety valve a32, a remote thermometer a33, and a remote pressure gauge a34 are sequentially installed between the tube side of heat exchanger b24 and vacuum regulator 31. The outlet of safety valve a32 is connected to the ammonia absorption system. A control valve c35 is installed on the branch pipeline connecting the remote pressure gauge a34 and vacuum regulator 31 to the ammonia absorption system. A remote flow meter a36 is installed at the outlet of vacuum regulator 31. Vacuum regulator 31 and remote... The pipeline between flow meters a36 is equipped with a remote pressure gauge b37, a density meter a38, and a remote thermometer b39 in sequence. The remote flow meter a36 is equipped with an online NOx analyzer 40, which converts the display of the remote flow meter a36 into the equivalent under standard conditions. The control valve a23 is automatically controlled through the remote flow meter a36, and the flow rate is generally maintained at 10 kg / h. The online NOx analyzer 40 participates in the internal calculation of the system in real time, and uses the calculated ammonia flow output as the control value of the remote flow meter a36. The air conditioning module 3 can prevent ammonia from rushing into the front pipeline when the pressure of the downstream pipeline is too high, thus achieving protection.

[0038] The ammonia output module 5 is used to output ammonia at a certain pressure. Therefore, a feedback mechanism is required to control the ammonia pressure. There are several ammonia output modules 5. Each ammonia output module 5 includes an injector b51 connected to a remote flow meter a36 via a pipeline. A control valve e52, a remote flow meter b53, and a remote pressure gauge c54 are sequentially installed on the pipeline between the remote flow meter a36 and the injector b51. A manual valve d55 is installed on the outlet pipeline of the injector b51.

[0039] The pressure regulating module 4 is used to regulate the pressure of ammonia gas by external compressed air so that the ammonia gas pressure is maintained at a suitable pressure for use in chemical reactions. The pressure regulating module 4 includes a hand valve e41, a check valve b42 and a hand valve b43 arranged sequentially on the inlet pipeline of the injector a16. A local pressure gauge b44, a control valve f45 and a remote pressure gauge d46 are arranged sequentially on the pipeline between the check valve b42 and the injector b51.

[0040] To prevent ammonia leaks, the ammonia concentration in the environment needs to be monitored in real time. When the ammonia concentration exceeds a predetermined value, emergency measures are activated to stop the ammonia vaporization process. This system also includes several ammonia analyzers 61 for detecting the ammonia concentration in the environment. An electric alligator clamp actuator a62 is installed at the outlet of the liquid ammonia cylinder 11, and an emergency stop button 63 is installed to control the interlocking and closing of the electric alligator clamp actuator a62, shut-off valve a22, shut-off valve b25 and control valve e52 based on the ammonia analyzer values. The entire system is set up in a sealed, independent room. Several online ammonia analyzers 61 are installed in the upper part of the room. When any one of the ammonia analyzers 61 monitors the data in real time and reaches 10-20 ppm, the entire system is interlocked to cut off the supply of liquid ammonia and ammonia gas, which can effectively prevent the escalation of ammonia and liquid ammonia leak accidents and reduce the harm of ammonia to the environment and personnel.

[0041] The following is a further explanation of the overall system, and its usage mainly includes the following five points:

[0042] 1. Check the airtightness of the angle valve and its connections.

[0043] With liquid ammonia cylinder 11 full, confirm that all angle valves are closed. Then, sequentially open hand valves e41, b43, a17, third angle valve 15, and second angle valve 14. When the local pressure gauge a18 shows 0.6 MPa (A), close hand valve b43. Use soapy water to check the airtightness of each angle valve and its pipeline connections. After confirming that the airtightness is acceptable, open the third angle valve 15 and observe the local pressure gauge a18 to release the pressure to 0.1 MPa (A). Then, close the third angle valve 15 and hand valve a17.

[0044] II. Putting the ammonia injection injector into operation

[0045] Open the manual valve d55, set the remote pressure gauge d46 to 0.4MPa(g), and automatically control the opening of the control valve f45. Switch the control valve e52 to manual mode and open the valve to 50%.

[0046] III. Introducing liquid ammonia into the heat exchanger

[0047] Activate safety valve a32, open first angle valve 13 and second angle valve 14, place electric alligator clamp actuator a62 on first angle valve 13, open shut-off valve a22, switch control valve a23 to manual mode, open the valve to 4%, activate heat exchanger b24 low-pressure steam shut-off valve b25, switch steam condensate control valve b26 to manual mode, slowly increase the valve opening until remote thermometer a33 displays 110℃.

[0048] IV. Automatic Control and Interlocking

[0049] Control valve B26 is automatically controlled via remote thermometer A33, with a setpoint of 110℃. When the temperature displayed on remote thermometer A33 exceeds 130℃, interlock shut-off valve B25 closes to prevent equipment overheating accidents. Control valve C35 is automatically controlled via remote pressure gauge A34, with a setpoint of 35 kPa(g). It automatically opens to relieve pressure when the pressure exceeds the setpoint, protecting the equipment. Control valve D28 is automatically controlled via remote level gauge A30, with a setpoint of 6%, periodically discharging impurities accumulated at the bottom of heat exchanger B24. When the level displayed on remote level gauge A30 exceeds 50%, shut-off valve A22 closes interlocked. Remote pressure gauge B37, density meter A38, and remote thermometer B39 participate in the control system calculations in real time. The flow meter A36 displays the equivalent flow rate under standard conditions. Control valve A23 is automatically controlled via remote flow meter A36, with a flow rate of 10 kg / h. A NOx online analyzer 40A provides real-time reference. The system calculates the required ammonia flow rate output as the control value for remote flow meter A36. One-third of the real-time single-volume output of remote flow meter A36 under standard conditions is used to form a cascade control with remote flow meter B53. Control valve E52 is automatically controlled through remote flow meter B53. The pressure of remote pressure gauge C54 is controlled at 50 kPa(A). When the pressure is in the range of 50-100 kPa(A), control valve F45 is increased to increase the corresponding valve opening and improve the pumping volume. When the pressure is higher than 100 kPa(A), the corresponding interlock control valve E52 is closed to prevent flue gas and air from being drawn back into the system. When any of the online ammonia analyzers in the sealed room reaches 10 ppm, the electric alligator clamp actuator A62, shut-off valve A22, shut-off valve B25 and control valve E52 are interlocked and closed. The system emergency stop button 63a is triggered to interlock and close the electric alligator clamp actuator A62, shut-off valve A22, shut-off valve B25 and control valve E52.

[0050] V. Switching and replacing liquid ammonia cylinders 11

[0051] When the weight displayed on the electronic scale 12 is 20 kg greater than the weight of the empty gas cylinder, remove the electric alligator clamp actuator a62, close the corresponding first angle valve 13 and second angle valve 14, and sequentially open the hand valves b43, c19, a17, and the third angle valve 15. When the local pressure gauge a18 displays 20 kPa (A), close the hand valve c19. When the local pressure gauge a18 displays 200 kPa (A), open the hand valve c19 again. Repeat the above vacuuming steps three times, and then close the third angle valve 15. Remove the outlet union of the first angle valve 13, replace the liquid ammonia cylinder 11, connect the outlet union of the first angle valve 13, open the third angle valve 15, and when the local pressure gauge a18 shows 0.6MPa(A), close the hand valve b43. Use soapy water to check the airtightness of each angle valve and its pipeline connection. After the airtightness is qualified, open the third hand valve 15, observe the local pressure gauge a18 to release the pressure to 0.1MPa(A), close the third angle valve and hand valve a17, and reinstall the electric alligator clamp actuator.

[0052] This invention is particularly suitable for adding ammonia injection into the flue gas SCR denitrification system of gas turbines to existing equipment. It has a small scope of modification, a small footprint, and a high safety factor for ammonia use. The ammonia produced by liquid ammonia vaporization is of high purity and will not clog the denitrification catalyst due to ammonia injection. It also utilizes the existing low-grade steam and instrument air in the workshop, resulting in low operating costs.

[0053] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0054] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A system for injecting ammonia into an SCR denitration system of a gas turbine, characterized in that, The application relates to an ammonia gas output device, which comprises the following modules: a liquid ammonia injection module (1) for outputting liquid ammonia gas in a flow-controllable manner to a vaporization module; a liquid ammonia vaporization module (2) for vaporizing liquid ammonia by heat exchange with steam and adjusting the liquid ammonia flow according to the feedback of a vacuum adjustment module (3); the vacuum adjustment module (3) for detecting the temperature, pressure, density and flow of ammonia gas and adjusting the vacuum degree of the ammonia gas to a certain value and then outputting the ammonia gas to a pressure adjustment module (4); the pressure adjustment module (4) for injecting compressed air into the ammonia gas to adjust the pressure of the mixed gas to a predetermined range and then outputting the mixed gas to an ammonia gas output module (5); the ammonia gas output module (5) for detecting and controlling the pressure and flow of the ammonia gas output; the liquid ammonia injection module (1) comprises a plurality of liquid ammonia cylinders (11), the bottom of the liquid ammonia cylinder (11) is provided with an electronic scale (12) for weighing, the outlet of the liquid ammonia cylinder (11) is provided with a first angle valve (13), a plurality of second angle valves (14) are arranged between the plurality of first angle valves (13), a plurality of third angle valves (15) are arranged in parallel with the second angle valves (14) between the plurality of first angle valves (13), an ejector a (16) is arranged on the pipeline between the plurality of third angle valves (15), a hand valve a (17) and a local pressure gauge a (18) are sequentially arranged between the pipeline between the plurality of third angle valves (15) and the ejector a (16), a hand valve c (19) is arranged at the outlet of the ejector a (16), and the ejector a (16) is used for collecting ammonia gas when the liquid ammonia cylinder (11) is replaced; the liquid ammonia vaporization module (2) comprises a heat exchanger a (21) connected with the pipeline between the plurality of second angle valves (14), the outlet of the tube side of the heat exchanger a (21) is connected with a workshop steam condensate pipeline through a pipeline, a cut-off valve a (22) and a control valve a (23) are sequentially arranged between the pipeline between the heat exchanger a (21) and the plurality of second angle valves (14), a heat exchanger b (24) is arranged on the shell side outlet of the heat exchanger a (21) and connected with the tube side inlet, the shell side inlet of the heat exchanger b (24) is connected with a workshop low-pressure steam pipeline, a cut-off valve b (25) is arranged on the shell side inlet of the heat exchanger b (24), the shell side outlet of the heat exchanger b (24) is connected with the tube side inlet of the heat exchanger a (21) through a pipeline, a control valve b (26) and a trap a (27) are arranged on the tube side outlet of the heat exchanger a (21), a control valve d (28) and a one-way valve a (29) are sequentially arranged at the bottom of the heat exchanger b (24), and a remote liquid level meter a (30) is arranged on the tube side bottom head of the heat exchanger b (24).

2. The ammonia injection system of claim 1, wherein, The vacuum regulating module (3) comprises a vacuum regulator (31) arranged on the outlet of the tube passage of the heat exchanger b (24), and a safety valve a (32), a remote thermometer a (33) and a remote pressure gauge a (34) are arranged in sequence between the tube passage of the heat exchanger b (24) and the vacuum regulator (31), the outlet of the safety valve a (32) is connected with the ammonia gas absorption system, a control valve c (35) is arranged on a branch pipeline connected with the ammonia gas absorption system between the remote pressure gauge a (34) and the vacuum regulator (31), a remote flowmeter a (36) is arranged on the outlet of the vacuum regulator (31), a NOx online analyzer (40) is arranged on the remote flowmeter a (36).

3. The ammonia injection system of claim 2, wherein, The ammonia gas output module (5) comprises a plurality of ejectors b (51) connected with the remote flowmeter a (36) through pipelines, a control valve e (52), a remote flowmeter b (53) and a remote pressure gauge c (54) are arranged in sequence on the pipeline between the remote flowmeter a (36) and the ejector b (51), and a hand valve d (55) is arranged on the outlet pipeline of the ejector b (51).

4. The ammonia injection system of claim 3, wherein, The pressure regulating module (4) comprises a hand valve e (41), a one-way valve b (42) and a hand valve b (43) arranged in sequence on the inlet pipeline of the ejector a (16), and a just-in-place pressure gauge b (44), a control valve f (45) and a remote pressure gauge d (46) are arranged in sequence on the pipeline between the one-way valve b (42) and the ejector b (51).

5. The ammonia injection system of claim 4, wherein, The ammonia gas analyzer (61) is arranged on the pipeline between the remote flowmeter a (36) and the ejector b (51), the outlet of the liquid ammonia cylinder (11) is provided with an electric alligator clamp actuator a (62), and an emergency stop button (63) is arranged for controlling the interlocking closing of the electric alligator clamp actuator a (62), the cut-off valve a (22), the cut-off valve b (25) and the control valve e (52) according to the value of the ammonia gas analyzer (61).

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