Ammonia-coal co-combustion device

Abstract

The utility model discloses an ammonia-coal co-combustion device which comprises air boxes arranged on the front wall and the rear wall of a hearth respectively. P partition plates in the horizontal direction are fixedly arranged in the air box to form p + 1 layers of air chambers, and an air volume adjusting valve is arranged on an inlet air duct of each layer of air chamber; more than two layers of coal combustors, more than two layers of ammonia combustors and more than one layer of over fire air devices are arranged in respective air chambers; the over-fire air devices are located above the coal combustors on all the layers, and the ammonia combustors on all the layers are arranged below the coal combustors on the lowest layer or above the coal combustors on the uppermost layer. All the ammonia combustors on the same layer are connected with the same ammonia fuel conveying pipeline, and the ammonia fuel conveying pipeline is provided with a system stop valve; through reasonable arrangement of the position of the ammonia burner, the ammonia burner can better stabilize burning and has higher burning efficiency, efficient and stable ammonia / coal coupling burning is achieved, air staged burning is strengthened, and the purpose of low NOx emission is achieved.

Description

Technical Field

[0001] The utility model relates to an ammonia-coal mixed burning combustion device, in particular to an ammonia-coal mixed burning combustion device used for a counter-burning boiler. Background Art

[0002] The coal-fired power industry is a high-carbon emission industry and faces huge challenges in carbon emission reduction. Therefore, it is of great significance to add zero-carbon fuel to coal-fired units. Green ammonia, as a zero-carbon fuel, is easier to store and transport, and is a good energy source for replacing coal and reducing carbon emissions. If ammonia fuel can effectively replace coal fuel, CO2 emissions can be greatly reduced, which has far-reaching significance and value for responding to global warming and achieving the "dual carbon" goal.

[0003] However, compared with conventional coal, ammonia fuel has a low calorific value, and is relatively difficult to ignite and burn stably. Existing combustion devices cannot ensure stable combustion of ammonia fuel while burning coal. In addition, due to the large differences in coal / ammonia combustion characteristics, if too high ammonia fuel is blended into a coal-fired boiler, the combustion efficiency will decrease and the nitrogen oxides in the flue gas will increase significantly, making it difficult to achieve efficient, low-nitrogen combustion of coal and ammonia coupling. Summary of the invention

[0004] The purpose of the utility model is to provide an ammonia-coal mixed combustion device in view of the above-mentioned deficiencies in the prior art, which, through the reasonable arrangement of the position of the ammonia burner, enables it to burn more stably and have higher combustion efficiency, realizes efficient and stable combustion of ammonia / coal coupling, and arranges a burnout wind device in the front and rear wall areas above the burner to enhance air staged combustion and achieve the purpose of low NOx emissions.

[0005] In order to achieve the above-mentioned purpose, the utility model provides an ammonia-coal mixed combustion device, comprising wind boxes respectively arranged on the front wall and the rear wall of the furnace; the characteristics are as follows: p horizontal partitions are fixedly arranged in the wind box, p≥4, forming p+1 layers of wind chambers, and an air volume regulating valve is arranged on the inlet air duct of each layer of wind chamber; more than two layers of coal burners, more than two layers of ammonia burners and more than one layer of burnout air devices are arranged in their respective wind chambers, and each layer of coal burners and each layer of ammonia burners are provided with more than two burners; the burnout air devices are all located above each layer of coal burners, and each layer of ammonia burners is respectively arranged below the lowest layer of coal burners or above the highest layer of coal burners; each ammonia burner on the same layer is connected to the same ammonia fuel delivery pipeline, and a system shut-off valve is provided on the ammonia fuel delivery pipeline.

[0006] When the utility model is used, each layer of coal burners, ammonia burners and burnout air devices are all supplied with air through the wind box. A partition is arranged in the wind box to divide the wind box into several independent wind chambers, which respectively provide air supply for the coal burner, ammonia burner and burnout air device. The air supply volume in each wind chamber is adjusted by the air volume regulating device according to the operation of the furnace. The utility model adopts a pure ammonia burner combined with a coal burner to be arranged in multiple dimensions on the front and rear walls of the furnace. Each ammonia burner is arranged at the lower part or the upper part of the coal burner. The high-temperature flue gas generated when the coal burner is put into operation creates better ignition conditions for the ammonia fuel sprayed into the furnace, which is beneficial to the ignition and stable combustion of the ammonia burner. The high temperature generated by the ignition and combustion of ammonia and the unburned binary and ternary components after decomposition can participate in the combustion of coal powder, promote the stable combustion and burnout of coal powder, and these two areas belong to the reducing atmosphere area. Spraying ammonia fuel in this reducing area can also greatly reduce the NOx generated by the combustion of coal powder in the flue gas. The overburnt air device is located above the coal burners in each layer, which is beneficial to reduce the excess air coefficient in the main combustion zone, enhance the reducibility of the main combustion zone, reduce the NOx content, and allow the unreacted binary and ternary components after decomposition to enter the overburnt air area together with the unburned carbon, promote the combustion of the unburned carbon, thereby improving the combustion efficiency, realizing efficient and stable combustion of ammonia / coal coupling, and achieving the purpose of low NOx emissions;

[0007] As a further improvement of the utility model, the ammonia burners arranged above the uppermost coal burners are all located below the burnout air device; the burnout rate can be improved;

[0008] As a further improvement of the utility model, the ammonia burners are more than three layers, the overburnt air devices are more than two layers, at least one layer of ammonia burners is arranged between the uppermost layer of coal burners and the lowermost layer of overburnt air devices, and at least one layer of ammonia burners is arranged between two layers of overburnt air devices; part of the ammonia fuel is injected between the two layers of overburnt air devices, which can increase the outlet flue gas temperature;

[0009] As a further improvement of the utility model, the ammonia burners of each layer are arranged one by one with the coal burners of each layer in the horizontal direction; this is more conducive to the ignition and stable combustion of the ammonia burners, and promotes the stable combustion and burnout of the coal powder;

[0010] As a further improvement of the utility model, a regulating valve is provided on each ammonia fuel delivery pipeline; the ammonia blending amount of each layer of ammonia burners can be adjusted to obtain a better combustion condition;

[0011] As a further improvement of the utility model, each layer of ammonia burners is arranged on the two side walls of the furnace according to the furnace space, and is respectively arranged below the lowest layer of coal burners or above the highest layer of coal burners;

[0012] In summary, the utility model reasonably arranges the position of the ammonia burner to enable it to have better stable combustion and higher combustion efficiency, realizes efficient and stable combustion of ammonia / coal coupling, and strengthens air staged combustion to achieve the purpose of low NOx emissions. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 This is the front view of the first embodiment of the utility model.

[0014] Figure 2 for Figure 1 Front view of the center front / back wall.

[0015] Figure 3 This is the front view of the second embodiment of the present utility model.

[0016] Figure 4 This is the front view of the third embodiment of the present utility model.

[0017] Figure 5 The front view of the fourth embodiment of the present invention. DETAILED DESCRIPTION

[0018] The utility model is further described below in conjunction with the accompanying drawings.

[0019] Embodiment 1

[0020] like Figure 1 to Figure 2 As shown, an ammonia-coal mixed combustion device of this embodiment comprises a wind box 1 respectively arranged on the front wall and the rear wall of the furnace; six horizontal partitions 2 are fixedly arranged in the wind box 1 to form a seven-layer wind chamber, and an air volume regulating valve 3 is arranged on the inlet air duct of each layer of the wind chamber; three layers of coal burners 4, 5, 6, two layers of ammonia burners 7, 8 and two layers of burnout air devices 9, 10 are arranged in their respective wind chambers, and each layer of coal burners and each layer of ammonia burners are provided with eight burners and arranged one by one in the horizontal direction; the two layers of burnout air devices 9 are both located above the coal burners 4 to 6 of each layer, one layer of ammonia burners 7 is located below the coal burners 4 of the lowest layer, and the other layer of ammonia burners 8 is located above the burners 6 of the highest layer and below the burnout air devices 9 of the lower layer; each ammonia burner 7 or 8 of the same layer is connected to the same ammonia fuel delivery pipeline, and the ammonia fuel delivery pipeline is provided with a system shut-off valve 11 and a regulating valve 12.

[0021] This embodiment is used for 1000MW level counter-combustion boilers; when in use, each layer of coal burners 4-6, ammonia burners 7, 8 and burnout air device 9 are all supplied with air through the wind box 1, and the wind box is divided into seven independent wind chambers by the partition 2, which respectively provide air supply for the coal burner, ammonia burner and burnout air device. According to the operation of the furnace, the air supply volume in each wind chamber is adjusted by the air volume regulating valve 3 on each wind chamber to achieve air depth classification; a single coal burner adopts conventional air depth classification, and its combustion air supply is divided into central air, primary air, inner secondary air and outer secondary air; this embodiment adopts a pure ammonia burner combined with a coal burner multi-dimensional arrangement method, and the ammonia burners 7 and 8 are arranged in two layers on the front and rear walls of the furnace, The first-stage ammonia burner 7 is arranged below the lowest coal burner 4. The area below the lowest burner belongs to the reducing atmosphere area. The flue gas temperature in this area is lower than 700-800°C, which is conducive to the decomposition and ignition of ammonia. The high-temperature flue gas generated by the ignition and combustion of ammonia and the unburned binary and ternary components after decomposition can be mixed into the coal powder combustion to promote the stable combustion and burnout of the coal powder. At the same time, it is arranged at the bottom of the furnace to avoid the low-temperature and undecomposed ammonia affecting the combustion of the coal powder in the early stage of combustion; the second-stage ammonia burner 8 is arranged between the uppermost coal burner 6 and the lower first-layer burnout air device 9. The flue gas temperature in this area is about 1100-1300°C, which is conducive to the decomposition and ignition of ammonia. This area belongs to the strong reducing atmosphere area of ​​the boiler. Injecting ammonia fuel in this strong reduction zone can, firstly, significantly reduce NOx generated by coal powder combustion in the flue gas, and secondly, the unreacted binary and ternary components after decomposition enter the burnout air zone together with the unburned carbon, promoting the burnout of the unburned carbon, thereby improving the combustion efficiency and achieving efficient and stable combustion of ammonia / coal coupling; the two-layer ammonia burners 7 and 8 are arranged at the lower part or the upper part of all coal burners respectively. The high-temperature flue gas generated when the coal burners are put into operation creates better ignition conditions for the ammonia fuel injected into the furnace, and the ammonia burners of each layer are arranged one by one with the coal burners of each layer in the horizontal direction, which is more conducive to the ignition and stable combustion of the ammonia burners; the burnout air devices 9 and 10 are arranged in layers above the second-stage ammonia burner 8 , which is beneficial to reduce the excess air coefficient of the main combustion zone, enhance the reducibility of the main combustion zone, strengthen the air staged combustion, and reduce the NOx content; the nozzle of the burnout air device can also be set to swing up and down and left and right. By adjusting the nozzle angle, the mixing in the furnace can be improved, the fuel burnout rate can be further improved, and the formation of nitrogen oxides can be effectively reduced; the ammonia fuel is delivered to the ammonia burner through the ammonia fuel delivery pipeline. When it is necessary to adjust the ammonia fuel blending ratio, the fuel amount can be controlled by controlling the regulating valve 12; when it is not necessary to blend ammonia fuel, the system shut-off valve 11 can be directly closed; the ratio of the first-stage and second-stage ammonia fuels can also be adjusted through the two regulating valves 12 to achieve the best combustion effect, and the ammonia heat input of 0-50% heat load can be achieved;

[0022] Embodiment 2

[0023] like Figure 3As shown, this embodiment is used for a 1000MW level counter-firing boiler, and the only difference from the first embodiment is that: a total of four layers of ammonia burners 21-24 are arranged, two layers of ammonia burners 21 and 22 are arranged below the bottom layer of coal burners 4, and two layers of ammonia burners 23 and 24 are arranged between the top layer of coal burners 6 and the first layer of burnout air device 9. A total of 48 ammonia burners are arranged, which can achieve the purpose of 0-100% ammonia blending or pure combustion.

[0024] Embodiment 3: This embodiment is used for 660MW level hedge combustion boiler.

[0025] like Figure 4 As shown, the difference between this embodiment and the first embodiment is that: three layers of ammonia burners 31, 32, 33 are provided, wherein one layer of ammonia burners 33 is provided between two layers of overburnt air devices 9, 10; 5 or 6 coal burners 4, 5, 6 are arranged on each layer, and a total of 30 or 36 coal burners are arranged in the whole furnace, and 5 or 6 ammonia burners 31, 32, 33 are arranged on each layer accordingly, and the number of ammonia burners 3 is 30 or 36. Part of the ammonia fuel is injected between the two layers of overburnt air devices 9, 10, which can increase the outlet flue gas temperature and realize ammonia-blended combustion with a heat input of 0-50%.

[0026] Embodiment 4: This embodiment is used for 660MW level hedge combustion boiler.

[0027] like Figure 5 As shown, the only difference between this embodiment and the third embodiment is that: a total of four layers of ammonia burners 41-44 are arranged, two layers of ammonia burners 41 and 42 are arranged below the bottom layer of coal burner 4, a layer of ammonia burner 43 is arranged between the top layer of coal burner 6 and the first layer of burnout air device 9, and a layer of ammonia burner 44 is arranged between the two layers of burnout air devices 9 and 10. A total of 48 ammonia burners are arranged to achieve the purpose of 0-100% ammonia blending or pure combustion.

[0028] The above embodiments are used for illustration, but it should be understood that the above embodiments are only used for the purpose of example and description, and are not intended to limit the present invention to the scope of the described embodiments.

Claims

1. An ammonia-coal mixed combustion device, comprising wind boxes respectively arranged on the front wall and the rear wall of the furnace; characterized in that: There are p horizontal partitions fixedly arranged in the wind box, p≥4, forming p+1 layers of wind chambers, and an air volume regulating valve is provided on the inlet air duct of each layer of wind chamber; more than two layers of coal burners, more than two layers of ammonia burners and more than one layer of burnout air devices are arranged in their respective wind chambers, and each layer of coal burners and each layer of ammonia burners are provided with more than two burners; the burnout air devices are located above the coal burners of each layer, and the ammonia burners of each layer are respectively arranged below the coal burners of the lowest layer or above the coal burners of the highest layer; the ammonia burners of the same layer are connected to the same ammonia fuel delivery pipeline, and the ammonia fuel delivery pipeline is provided with a system shut-off valve.

2. The ammonia-coal mixed combustion device according to claim 1, characterized in that: The ammonia burners arranged above the uppermost coal burners are all located below the burnout air device.

3. The ammonia-coal mixed combustion device according to claim 1, characterized in that: The ammonia burners are arranged in more than three layers, the overburnt air devices are arranged in more than two layers, at least one layer of ammonia burners is arranged between the uppermost layer of coal burners and the lowermost layer of overburnt air devices, and at least one layer of ammonia burners is arranged between two layers of overburnt air devices.

4. An ammonia-coal mixed combustion device as claimed in claim 1, 2 or 3, characterized in that: The ammonia burners on each layer and the coal burners on each layer are arranged one by one in the horizontal direction.

5. The ammonia-coal mixed combustion device according to claim 4, characterized in that: Regulating valves are installed on the ammonia fuel delivery pipelines.

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