Low-carbon peak regulation system and method for blending combustion of ammonia fuel

Abstract

The invention discloses a low-carbon peak regulation system and method for blending combustion of ammonia fuel. The low-carbon peak regulation system comprises a coal-fired boiler, a coal-fired burner, an ammonia burner, a coal-fired unit generator, a clean energy generator, an ammonia preparation device, an ammonia storage system, an ammonia pipeline, a first switch, a second switch, a third switch, a first transformer, a second transformer, a third transformer, an output line and a power grid. The ammonia preparation device, the ammonia storage system and the ammonia combustor are connected through ammonia pipelines. According to the invention, excess electricity generated by the coal-fired unit is utilized to prepare ammonia, so that the actual on-grid power of the coal-fired unit reaches the required on-grid power; under the full load of a coal-fired unit, ammonia is injected into a main combustion area in the furnace by adopting a proper flow rate and mode, and on the premise that the influence on the combustion stability in the furnace, the NOX concentration of a hearth outlet and the carbon content of fly ash is small, the renewable energy consumption capacity of the system is effectively improved, and carbon emission is reduced.

Description

Technical Field

[0001] The present invention belongs to the technical field of power generation sets, and in particular relates to a low-carbon peak-shaving system and method for mixing and burning ammonia fuel. Background Art

[0002] Seeking low-carbon energy alternatives is an important measure for coal-fired units to reduce carbon emissions. Ammonia, as a zero-carbon fuel, is more energy-efficient in storage and transportation, has more mature technology and is safer. It is an ideal candidate fuel for achieving low-carbon emissions and has great potential to replace coal. Therefore, the ammonia-blended combustion of coal-fired units has received considerable attention in recent years.

[0003] The properties of ammonia fuel and the design fuel of coal-fired units are quite different. The impacts of the ammonia combustion process coupled with coal-fired units mainly include: 1) the ammonia combustion reaction is slow, and there is a hidden danger of flame instability; 2) ammonia carries a large amount of nitrogen, and there is a NO X The hidden danger of excessive concentration; 3) The combustion temperature of ammonia is relatively low, and there is a hidden danger of excessive carbon content in fly ash. Summary of the invention

[0004] The technical problem to be solved by the present invention is to overcome the defects of the above-mentioned prior art and provide a low-carbon peak-shaving system and method for mixing ammonia fuel, which uses the excess electricity generated by the coal-fired unit to produce ammonia, so that the actual grid-connected power of the coal-fired unit can reach the required grid-connected power; when the coal-fired unit is at full load, ammonia is injected into the furnace with a suitable flow rate and method to reduce the relatively low O2 and high NO X Concentration area, in the furnace combustion stability, furnace outlet NO X On the premise that the concentration and fly ash carbon content are less affected, the ammonia blending ratio can be guaranteed to be above 20%, so as to effectively improve the system's renewable energy absorption capacity and reduce carbon emissions.

[0005] In order to achieve the above-mentioned object of the invention, the present invention provides the following technical solutions.

[0006] In a first aspect, the present invention provides a low-carbon peak-shaving system for ammonia fuel, which includes a coal-fired boiler, a coal-fired burner, an ammonia burner, a coal-fired unit generator, a clean energy generator, an ammonia preparation device, an ammonia storage system, an ammonia pipeline, a first switch, a second switch, a third switch, a first transformer, a second transformer, a third transformer, an output line and a power grid; The coal-fired generator is connected to the power grid via a first switch, a first transformer and an output line; The coal-fired unit generator is connected to the ammonia preparation device via a second switch and a second transformer; The clean energy generator is connected to the ammonia preparation device via a third switch and a third transformer; The ammonia preparation device, the ammonia storage system and the ammonia burner are connected via an ammonia pipeline; The coal-fired burner and the ammonia burner are installed on a coal-fired boiler.

[0007] Preferably, the ammonia pipeline is provided with an ammonia pressurizing device, and the ammonia pressurizing device is located between the ammonia preparation device and the ammonia storage system.

[0008] Preferably, an ammonia pressure reducing device is provided on the ammonia pipeline, and the ammonia pressure reducing device is located between the ammonia storage system and the ammonia burner.

[0009] Preferably, the coal-fired boiler is provided with a secondary air volume control system, and the secondary air volume control system is used to control the secondary air volume of the coal-fired boiler.

[0010] Preferably, the coal-fired boiler is provided with a burnout air volume control system, and the burnout air volume control system is used to control the burnout air volume of the coal-fired boiler.

[0011] Preferably, the low-carbon peak-shaving system further comprises a coal quantity control system, and the coal quantity control system is used to control the coal quantity of the coal-fired burner.

[0012] Preferably, the low-carbon peak-shaving system further comprises an ammonia quantity control system, and the ammonia quantity control system is used to control the ammonia quantity burned by the ammonia burner.

[0013] Preferably, the low-carbon peak-shaving system further comprises a power controller, which is respectively connected to the coal-fired unit generator, the second switch and the power grid.

[0014] Furthermore, the operation method of the low-carbon peak-shaving system is as follows: During the off-peak period of the power grid, the power controller obtains the difference between the grid-connected power of the coal-fired generator required by the grid and the actual power generation power of the coal-fired generator, closes the second switch, and uses the excess power generated by the coal-fired generator to produce ammonia through the ammonia preparation device, so that the actual grid-connected power of the coal-fired generator reaches the required grid-connected power; When the power grid needs a low-carbon peak-shaving system to absorb renewable energy, the third switch is closed, and the electricity generated by the clean energy generator is used to produce ammonia through the ammonia preparation device; the ammonia produced by the ammonia preparation device is sent to the ammonia storage system through the ammonia pipeline; Under full load of the coal-fired unit, the ammonia stored in the ammonia storage system is sent to the ammonia burner through the ammonia pipeline to ensure that the ammonia blending ratio is above 20%. As the load of the coal-fired unit increases, the ammonia blending ratio is increased; during blending, ammonia is injected into the main combustion zone in the furnace at an appropriate flow rate and method to keep the excess air coefficient of the main combustion zone below 0.7. At the same time, the temperature field of the main combustion zone and the NO at the furnace outlet are monitored. X concentration and carbon content of fly ash.

[0015] In a second aspect, the present invention provides a low-carbon peak-shaving method for blending ammonia fuel, which is implemented by the above-mentioned low-carbon peak-shaving system for blending ammonia fuel, and comprises: Step 1: determine whether it is necessary to quickly reduce the output power of the coal-fired unit. If the coal-fired unit needs to quickly reduce the output power, execute step 2; determine whether the system needs to absorb renewable energy. If the system needs to absorb renewable energy, execute step 3; Step 2, controlling the power of the ammonia preparation device according to the target power reduction value of the coal-fired unit to quickly reduce the output power of the coal-fired unit; Step 3, controlling the power of the ammonia preparation device according to the target consumption value of renewable energy of the power grid to consume the renewable energy of the power grid; Step 4: When the coal-fired unit is at full load, ammonia is injected into the main combustion zone in the furnace using a suitable flow rate and method, and the ammonia blending ratio increases as the load of the coal-fired unit increases; Step 5, adjusting the secondary air volume control system and the burnout air volume control system of the coal-fired boiler to keep the excess air coefficient of the main combustion zone below 0.7; Step 6: Monitor the temperature field of the main combustion zone and the NO at the furnace outlet X concentration and fly ash carbon content, if the temperature of the main combustion zone is lower than the minimum stable combustion temperature of the pulverized coal, and the furnace outlet NO X If the concentration or carbon content of fly ash is higher than the design value, it can be adjusted by reducing the amount of ammonia burned in the ammonia burner.

[0016] The beneficial effects of the present invention are as follows: during the off-peak period of power grid electricity consumption, the excess electricity generated by the coal-fired unit is used to produce ammonia, so that the actual grid power of the coal-fired unit reaches the required grid power; under the full load of the coal-fired unit, the ammonia blending ratio is guaranteed to be above 20%, which effectively improves the renewable energy absorption capacity of the system and reduces carbon emissions, and at the same time has an impact on the combustion stability in the furnace and the NO at the furnace outlet. X The concentration and carbon content of fly ash have little impact. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 This is a schematic structural diagram of a low-carbon peak-shaving system using ammonia as a fuel in the present invention; Figure 2 The present invention is a flow chart of a low-carbon peak-shaving method using ammonia-blended fuel. DETAILED DESCRIPTION

[0018] The following will further describe the specific implementation of the present invention in combination with the accompanying drawings of the embodiments of the present invention, so that the technical solution of the present invention is easier to understand and grasp. It should be understood that the specific embodiments described here are only used to explain part of the embodiments of the invention, rather than all the embodiments. Other embodiments obtained by ordinary technicians in this field without making creative work are all within the scope of protection of the present invention.

[0019] Example 1 Please see attached Figure 1 , which is a low-carbon peak-shaving system for ammonia fuel blending of the present invention, comprising a coal-fired boiler 1, a coal-fired burner 2, an ammonia burner 3, a coal-fired unit generator 4, a clean energy generator 5, a coal quantity control system 6, an ammonia quantity control system 7, a secondary air volume control system 8, a burnout air volume control system 9, an ammonia preparation device 10, an ammonia storage system 11, an ammonia pipeline 12, an ammonia pressurizing device 13, an ammonia pressure reducing device 14, a power controller 15, a first switch 16, a second switch 17, a third switch 18, a first transformer 19, a second transformer 20, a third transformer 21, an output line 22 and a power grid 23.

[0020] The coal-fired generator 4 is connected to a power grid 23 via a first switch 16 , a first transformer 19 and an output line 22 .

[0021] The coal-fired unit generator 4 is connected to the ammonia preparation device 10 via a second switch 17 and a second transformer 20 .

[0022] The clean energy generator 5 is connected to the ammonia preparation device 10 via a third switch 18 and a third transformer 21 .

[0023] The ammonia preparation device 10, the ammonia storage system 11, and the ammonia burner 3 are connected through an ammonia pipeline 12. The ammonia pipeline 12 is provided with an ammonia pressurizing device 13 and an ammonia decompressing device 14, wherein the ammonia pressurizing device 13 is located between the ammonia preparation device 10 and the ammonia storage system 11, and the ammonia decompressing device 14 is located between the ammonia storage system 11 and the ammonia burner 3.

[0024] The coal-fired burner 2 and the ammonia burner 3 are installed on the coal-fired boiler 1. The coal-fired boiler 1 is provided with a secondary air volume control system 8 and a burnout air volume control system 9. The secondary air volume control system 8 is used to control the secondary air volume of the coal-fired boiler 1, and the burnout air volume control system 9 is used to control the burnout air volume of the coal-fired boiler 1.

[0025] The coal quantity control system 6 is used to control the coal quantity of the coal-fired burner 2 , and the ammonia quantity control system 7 is used to control the ammonia quantity of the ammonia burner 3 .

[0026] The power controller 15 is respectively connected to the coal-fired unit generator 4 , the second switch 17 and the power grid 23 , and is used to control the coal-fired unit generator 4 and the second switch 17 .

[0027] The operation method of the low-carbon peak-shaving system of the present invention is as follows: When it is determined that the power grid 23 is in a low-power consumption period, the power controller 15 obtains the difference between the online power of the coal-fired unit generator 4 required by the power grid 23 and the actual power generation power of the coal-fired unit generator 4, closes the second switch 17, and uses the excess electricity generated by the coal-fired unit generator 4 to produce ammonia through the ammonia preparation device 10, so that the actual online power of the coal-fired unit generator 4 reaches the required online power.

[0028] When it is determined that the power grid 23 needs to systematically absorb renewable energy, the third switch 18 is closed, and ammonia is produced through the ammonia production device 10 using the electricity generated by the clean energy generator 5 .

[0029] The ammonia produced by the ammonia production device 10 passes through the ammonia pressurizing device 13 and is sent to the ammonia storage system 11 through the ammonia pipeline 12 .

[0030] When the coal-fired unit is under full load, the ammonia stored in the ammonia storage system 11 is sent to the ammonia burner 3 through the ammonia pressure reducing device 14 and the ammonia pipeline 12. When the coal-fired unit is under full load, the coal quantity control system 6 and the ammonia quantity control system 7 are controlled to ensure that the ammonia blending ratio is above 20%. As the load of the coal-fired unit increases, the coal quantity control system 6 and the ammonia quantity control system 7 are controlled to increase the ammonia blending ratio. During blending, ammonia is injected into the coal-fired boiler 1 with a suitable flow rate and method. X Concentration area (i.e. main combustion area). Control the secondary air volume control system 8 and the burnout air volume control system 9 to keep the excess air coefficient of the main combustion area of ​​the coal-fired boiler 1 below 0.7. Monitor the temperature field of the main combustion area of ​​the coal-fired boiler 1, the NO X Concentration, fly ash carbon content and other parameters.

[0031] If the temperature of the main combustion zone of the coal-fired boiler 1 is lower than the minimum stable combustion temperature of the pulverized coal, it is adjusted by reducing the amount of ammonia burned by the ammonia burner 3 .

[0032] If the coal-fired boiler 1 furnace outlet NO X If the concentration is higher than the design value, it is adjusted by reducing the amount of ammonia burned in the ammonia burner 3.

[0033] If the carbon content of fly ash at the furnace outlet of the coal-fired boiler 1 is higher than the design value, it is adjusted by reducing the amount of ammonia burned by the ammonia burner 3.

[0034] Example 2 Please refer to the attached Figure 2 The present invention provides a low-carbon peak-shaving method for blending ammonia fuel. The method is implemented by a low-carbon peak-shaving system for blending ammonia fuel described in Example 1. The specific steps of the method are as follows: Step 1: determine whether it is necessary to quickly reduce the output power of the coal-fired unit. If the coal-fired unit needs to quickly reduce the output power, execute step 2; determine whether the system needs to absorb renewable energy. If the system needs to absorb renewable energy, execute step 3; Step 2, controlling the power of the ammonia preparation device according to the target power reduction value of the coal-fired unit to quickly reduce the output power of the coal-fired unit; Step 3, controlling the power of the ammonia preparation device according to the target consumption value of renewable energy of the power grid to consume the renewable energy of the power grid; Step 4: When the coal-fired unit is at full load, ammonia is injected into the furnace at a suitable flow rate and method to reduce the O2 content and NO content. X In the concentration region, the ammonia blending ratio increases with the load of the coal-fired unit; Step 5, adjust the secondary air volume control system and the burnout air volume control system to keep the excess air coefficient of the main combustion zone below 0.7; Step 6: Monitor the temperature field of the main combustion zone and the NO at the furnace outlet X concentration and fly ash carbon content, if the temperature of the main combustion zone is lower than the minimum stable combustion temperature of the pulverized coal, and the furnace outlet NO X If the concentration or carbon content of fly ash is higher than the design value, it can be adjusted by reducing the amount of ammonia burned in the ammonia burner.

[0035] The above description of the disclosed embodiments enables those skilled in the art to implement or use the present invention. Modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein.

Claims

1. A low-carbon peak-shaving system using ammonia as fuel, characterized in that: The invention comprises a coal-fired boiler (1), a coal-fired burner (2), an ammonia burner (3), a coal-fired unit generator (4), a clean energy generator (5), an ammonia preparation device (10), an ammonia storage system (11), an ammonia pipeline (12), a first switch (16), a second switch (17), a third switch (18), a first transformer (19), a second transformer (20), a third transformer (21), an output line (22) and a power grid (23); The coal-fired generator (4) is connected to a power grid (23) via a first switch (16), a first transformer (19) and an output line (22); The coal-fired generator (4) is connected to the ammonia production device (10) via a second switch (17) and a second transformer (20); The clean energy generator (5) is connected to the ammonia production device (10) via a third switch (18) and a third transformer (21); The ammonia production device (10), the ammonia storage system (11) and the ammonia burner (3) are connected via an ammonia pipeline (12); The coal-fired burner (2) and the ammonia burner (3) are installed on the coal-fired boiler (1).

2. A low-carbon peak-shaving system using ammonia as fuel according to claim 1, characterized in that: An ammonia pressurizing device (13) is provided on the ammonia pipeline (12), and the ammonia pressurizing device (13) is located between the ammonia preparation device (10) and the ammonia storage system (11).

3. The low-carbon peak-shaving system using ammonia as fuel according to claim 1, characterized in that: An ammonia pressure reducing device (14) is provided on the ammonia pipeline (12), and the ammonia pressure reducing device (14) is located between the ammonia storage system (11) and the ammonia burner (3).

4. The low-carbon peak-shaving system using ammonia as fuel according to claim 1, characterized in that: The coal-fired boiler (1) is provided with a secondary air volume control system (8), and the secondary air volume control system (8) is used to control the secondary air volume of the coal-fired boiler (1).

5. The low-carbon peak-shaving system using ammonia as fuel according to claim 1, characterized in that: The coal-fired boiler (1) is provided with a burnout air volume control system (9), and the burnout air volume control system (9) is used to control the burnout air volume of the coal-fired boiler (1).

6. The low-carbon peak-shaving system using ammonia as fuel according to claim 1, characterized in that: It also includes a coal quantity control system (6), which is used to control the coal quantity of the coal-fired burner (2).

7. The low-carbon peak-shaving system using ammonia as fuel according to claim 1, characterized in that: It also includes an ammonia quantity control system (7), which is used to control the ammonia quantity burned by the ammonia burner (3).

8. The low-carbon peak-shaving system using ammonia as fuel according to claim 1, characterized in that: The invention also comprises a power controller (15), wherein the power controller (15) is respectively connected to the coal-fired unit generator (4), the second switch (17) and the power grid (23).

9. The low-carbon peak-shaving system using ammonia as fuel according to claim 8, characterized in that: The operation method of the low-carbon peak-shaving system is as follows: During the off-peak period of the power grid, the power controller obtains the difference between the grid-connected power of the coal-fired generator required by the grid and the actual power generated by the coal-fired generator, closes the second switch, and uses the excess power generated by the coal-fired generator to produce ammonia through the ammonia preparation device, so that the actual grid-connected power of the coal-fired generator reaches the required grid-connected power; When the power grid needs a low-carbon peak-shaving system to absorb renewable energy, the third switch is closed, and the electricity generated by the clean energy generator is used to produce ammonia through the ammonia production device; the ammonia produced by the ammonia production device is sent to the ammonia storage system through the ammonia pipeline; Under full load of the coal-fired unit, the ammonia stored in the ammonia storage system is fed into the ammonia burner through the ammonia pipeline to ensure that the ammonia blending ratio is above 20%. As the load of the coal-fired unit increases, the ammonia blending ratio is increased. During blending, ammonia is injected into the main combustion zone in the furnace at an appropriate flow rate and method to maintain the excess air coefficient of the main combustion zone below 0.

7. At the same time, the temperature field of the main combustion zone and the NO at the furnace outlet are monitored. X concentration and carbon content of fly ash.

10. A low-carbon peak-shaving method for ammonia-blended fuel, which is implemented using a low-carbon peak-shaving system for ammonia-blended fuel according to any one of claims 1 to 8, characterized in that: include: Step 1: determine whether the output power of the coal-fired unit needs to be quickly reduced. If the coal-fired unit needs to quickly reduce the output power, execute step 2; Determine whether the system needs to absorb renewable energy. If the system needs to absorb renewable energy, execute step 3. Step 2: controlling the power of the ammonia production device according to the target power reduction value of the coal-fired unit to quickly reduce the output power of the coal-fired unit; Step 3: Control the power of the ammonia production device according to the target consumption value of renewable energy of the power grid to consume the renewable energy of the power grid; Step 4: When the coal-fired unit is at full load, ammonia is injected into the main combustion zone of the furnace using an appropriate flow rate and method, and the ammonia ratio increases as the load of the coal-fired unit increases; Step 5: Adjust the secondary air volume control system and the burnout air volume control system of the coal-fired boiler to keep the excess air coefficient of the main combustion zone below 0.7; Step 6: Monitor the temperature field of the main combustion zone and the NO at the furnace outlet. X Concentration and fly ash carbon content, if the main combustion zone temperature is lower than the minimum stable combustion temperature of pulverized coal, the furnace outlet NO X If the concentration or carbon content of fly ash is higher than the design value, it can be adjusted by reducing the amount of ammonia burned in the ammonia burner.

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