A high-efficiency combustion device and method for lignite in high-altitude environments

Abstract

This invention provides a high-efficiency lignite combustion device and method based on high-altitude environments, relating to the field of lignite combustion. The device includes a furnace, a cyclone separator connected to the dilute phase zone inside the furnace, and an economizer for reusing waste heat from flue gas. The furnace is equipped with water-cooled partition walls that divide the furnace into multiple combustion chambers. Connecting air ducts for communication between the multiple combustion chambers are provided on the water-cooled partition walls. This invention divides the furnace into multiple combustion chambers through multiple sets of longitudinal and transverse water-cooled partition walls, enabling separated combustion. This allows coal particles to mix within multiple combustion chambers, ensuring flame combustion in each chamber. The combination of water-cooled walls within each combustion chamber, along with the first air duct, second air duct, and balance holes, increases the residence time of particles within the furnace, thereby promoting coke burnout.

Description

Technical Field

[0001] This invention relates to the field of lignite combustion technology, and in particular to a high-efficiency lignite combustion device and method based on high-altitude environments. Background Technology

[0002] Circulating fluidized bed combustion technology has been widely used worldwide due to its advantages such as high efficiency and energy saving, easy control of pollutant emissions, and wide fuel adaptability. Currently, the parameters of thermal power generating units worldwide have evolved from supercritical (25.0 MPa, 540℃-566℃) to ultra-supercritical (24-30.0 MPa, 580℃-610℃) and above. The power generation efficiency of ultra-supercritical units can reach 45%-47%, which is 3%-4% higher than that of supercritical units, further improving economic efficiency.

[0003] Combustion and heat transfer of lignite under high altitude and low pressure conditions differ from those in conventional environments. Low pressure accelerates the release of volatile matter from fuel particles, especially for high-volatile lignite, increasing the proportion of combustion in the dense phase zone. The low pressure environment also reduces oxygen concentration, leading to a longer coke burnout time. To address these issues, this invention proposes a high-efficiency lignite combustion device and method based on high-altitude environments to solve the problems existing in the prior art. Summary of the Invention

[0004] To address the aforementioned problems, this invention proposes a high-efficiency lignite combustion device and method based on high-altitude environments. This high-efficiency lignite combustion device for high-altitude environments divides the interior of the furnace into multiple combustion chambers through multiple sets of longitudinal water-cooled walls in conjunction with transverse water-cooled walls, enabling separate combustion. This allows coal particles to mix within multiple combustion chambers, ensuring that each combustion chamber has a flame. In conjunction with the water-cooled walls within each combustion chamber, as well as the coordination of the first air duct, the second air duct, and the balance hole, the residence time of particles in the furnace is increased, thereby promoting complete coke combustion.

[0005] To achieve the objectives of this invention, the following technical solution is provided: a high-efficiency lignite combustion device based on high-altitude environments, comprising a furnace, a cyclone separator connected to the dilute phase zone inside the furnace, and an economizer for reusing waste heat from flue gas. The furnace is internally equipped with a water-cooled partition wall, which divides the furnace interior into multiple combustion chambers. The water-cooled partition wall is provided with connecting air ducts for communication between the multiple combustion chambers. Furthermore, the water-cooled partition wall is also equipped with features to ensure the uniformity of gas-solid flow among the multiple combustion chambers. The furnace has a steam-liquid treatment chamber at the top for transporting and processing steam and liquid. Multiple combustion chambers are equipped with water-cooled walls, the input and output ends of which are connected to the steam-liquid treatment chamber. The dilute phase zones of multiple combustion chambers are also equipped with screen-type superheaters, the input and output ends of which are connected to the steam-liquid treatment chamber. The dense phase zone of the furnace has a coal feeder, below which is a burner. The bottom of the furnace has a slag discharge port, and the bottom of the economizer has a flue gas pipe.

[0006] A further improvement is that the water-cooled partition wall includes a horizontal water-cooled wall and a vertical water-cooled wall. There is one set of horizontal water-cooled walls and multiple sets of vertical water-cooled walls. The multiple sets of vertical water-cooled walls are arranged perpendicularly to the horizontal water-cooled walls.

[0007] A further improvement is that the connecting air duct includes a first air duct and a second air duct. The first air duct is distributed on the horizontal water-cooled wall, and the second air duct is distributed on the vertical water-cooled wall. The positions of the first air duct and the second air duct are staggered at different heights.

[0008] A further improvement is that: the balancing holes are provided in multiple sets, and the multiple sets of balancing holes are respectively distributed on the horizontal water-cooled wall and the vertical water-cooled wall, and the number of balancing holes on the horizontal water-cooled wall is greater than the number of balancing holes on the vertical water-cooled wall.

[0009] A further improvement is that a mesh grille is also provided in the first and second air ducts, and both the water-cooled partition wall and the mesh grille are made of fire-resistant and corrosion-resistant materials.

[0010] A further improvement is that the water-cooled wall is composed of multiple sets of water-cooled rings, which are spaced 2-5 cm apart and interconnected.

[0011] A further improvement is that the cyclone separator is provided in multiple sets, all of which are located between the furnace and the economizer. The bottoms of the multiple sets of cyclone separators are connected by a rectifier pipe, and the bottom of the rectifier pipe is provided with a return pipe that communicates with the combustion chamber.

[0012] A further improvement is that the bottom of the cyclone separator is also provided with a first fan, which is connected to the economizer. The first fan is provided with a first air conveying pipe and a second air conveying pipe. The outlet of the first air conveying pipe is located below the opposite side of the feeder's discharge end, and the output end of the first air conveying pipe faces the feeder's discharge end. The second air conveying pipe is located above the first air conveying pipe.

[0013] A further improvement is that: an air supply ring is provided on the outer wall of the furnace, a second fan is provided on the first fan, a third air supply pipe is provided on the second fan, one end of the third air supply pipe is connected to the air supply ring, the inner side of the air supply ring is connected to multiple sets of combustion chambers, and the return pipe is provided through the third air supply pipe.

[0014] The combustion method using the above-mentioned high-efficiency lignite combustion device based on high-altitude environment includes the following:

[0015] S1. Lignite enters the furnace through the feeder. The first air duct of the first blower blows air into the lignite entering the furnace, causing the lignite particles to float at the bottom of the furnace. At the same time, the second air duct blows air into the furnace, allowing the lignite particles to mix with the oxygen in the air, increasing the oxygen content of the fuel. Meanwhile, the air at the air inlet of the first blower is preheated by the economizer, which dries the floating coal particles, reducing the moisture content of the coal particles and increasing the oxygen content of the fuel. Then the burner ignites.

[0016] S2. The water-cooled partition wall divides the furnace interior into multiple combustion chambers. The flames and flue gas after combustion enter the multiple combustion chambers respectively. At the same time, the second fan works to deliver air to the multiple combustion chambers, thereby increasing the combustion effect inside each combustion chamber. The water-cooled partition wall is also equipped with connecting channels and balance holes to ensure the uniformity of gas-solid flow in each combustion chamber inside the furnace, and to increase the residence time of coal particles inside the furnace.

[0017] S3. At the same time, each combustion chamber is equipped with a water-cooled wall as a heat-receiving component. The water-cooled wall is composed of multiple sets of spaced water-cooled rings, thereby increasing the contact between each set of water-cooled rings and the flame, thereby controlling the deviation of the heat-receiving side of the heat-receiving surface and ensuring the heating effect of the water-cooled wall.

[0018] S4. The cyclone separator separates the particles in the flue gas. The flue gas is sent to the economizer for preheating and utilization, while the shell is sent back into the furnace for circulating combustion.

[0019] S5. After the water-cooled wall is heated, the internal cold water boils and evaporates into steam. The steam is separated and processed by the steam-liquid treatment chamber and then sent to the steam turbine. The liquid is cooled and then recycled.

[0020] The beneficial effects of this invention are as follows: This invention divides the interior of the furnace into multiple combustion chambers by using multiple sets of longitudinal water-cooled walls in conjunction with transverse water-cooled walls, allowing for separate combustion. This enables coal particles to mix within multiple combustion chambers, ensuring that each combustion chamber has a flame. In conjunction with the water-cooled walls within each combustion chamber, as well as the coordination of the first air duct, the second air duct, and the balance holes, the residence time of particles in the furnace is increased, thereby promoting coke burnout. The invention employs a stratified combustion mode that combines high-temperature combustion of volatiles in the dense phase zone with enhanced coke burnout in the dilute phase zone, thus balancing combustion efficiency and pollutant control. Attached Figure Description

[0021] Figure 1 This is a three-dimensional schematic diagram of the present invention.

[0022] Figure 2 This is a schematic diagram showing the location of the screen-type superheater of the present invention.

[0023] Figure 3 This is a schematic diagram of the structure of the water-cooled wall of the present invention.

[0024] Figure 4 This is a schematic diagram of the structure of the water-cooled partition wall of the present invention.

[0025] The components are as follows: 1. Furnace; 2. Cyclone separator; 3. Economizer; 4. Water-cooled partition wall; 5. Combustion chamber; 6. Balance hole; 7. Vapor-liquid treatment chamber; 8. Water-cooled wall; 9. Screen-type superheater; 10. Coal feeder; 11. Burner; 12. Ash discharge port; 13. Flue pipe; 14. Horizontal water-cooled wall; 15. Vertical water-cooled wall; 16. First air duct; 17. Second air duct; 18. Mesh grid; 19. Water-cooled ring; 20. Rectifier tube; 21. Return tube; 22. First fan; 23. First air supply pipe; 24. Second air supply pipe; 25. Air supply ring; 26. Second fan; 27. Third air supply pipe. Detailed Implementation

[0026] To enhance understanding of the present invention, the present invention will be further described in detail below with reference to embodiments. These embodiments are only used to explain the present invention and do not constitute a limitation on the scope of protection of the present invention.

[0027] according to Figures 1-4As shown, this embodiment proposes a high-efficiency lignite combustion device based on high-altitude environments, including a furnace 1, a cyclone separator 2 connected to the dilute phase zone inside the furnace 1, and an economizer 3 for reusing waste heat from flue gas. The furnace 1 is equipped with a water-cooled partition wall 4, which divides the interior of the furnace 1 into multiple combustion chambers 5. The water-cooled partition wall 4 is provided with connecting air ducts for communication between the multiple combustion chambers 5, and also with balance holes 6 to ensure uniform gas-solid flow among the multiple combustion chambers 5. The top of the furnace 1 is provided with... The furnace 1 has a vapor-liquid treatment chamber 7 for transporting and processing steam and liquid. Multiple sets of combustion chambers 5 are equipped with water-cooled walls 8. The input and output ends of the water-cooled walls 8 are connected to the vapor-liquid treatment chamber 7. Multiple combustion chambers 5 are also equipped with screen-type superheaters 9 in their dilute phase zones. The input and output ends of the screen-type superheaters 9 are connected to the vapor-liquid treatment chamber 7. The furnace 1 has a coal feeder 10 in its dense phase zone. A burner 11 is located below the coal feeder 10. The furnace 1 has a slag discharge port 12 at its bottom. The economizer 3 has a flue gas pipe 13 at its bottom.

[0028] The water-cooled partition wall 4 divides the interior of the furnace 1 into multiple combustion chambers 5, which are connected by connecting air ducts. At the same time, balance holes 6 are set to ensure the uniformity of gas-solid flow in each combustion chamber 5, so as to achieve efficient desulfurization in the furnace and reduce the generation of NOx emissions. The separately set water-cooled wall 8 greatly increases the heat-receiving area of ​​the water-cooled wall 8, thereby increasing the heating effect and further increasing the efficiency of steam generation.

[0029] The water-cooled partition wall 4 includes a horizontal water-cooled wall 14 and a vertical water-cooled wall 15. There is one set of horizontal water-cooled walls 14 and multiple sets of vertical water-cooled walls 15. The multiple sets of vertical water-cooled walls 15 are arranged perpendicularly to the horizontal water-cooled walls 14.

[0030] The connecting air duct includes a first air duct 16 and a second air duct 17. The first air duct 16 is distributed on the transverse water-cooled wall 14, and the second air duct 17 is distributed on the longitudinal water-cooled wall 15. The positions of the first air duct 16 and the second air duct 17 are staggered.

[0031] The balancing holes 6 are provided in multiple sets, and the multiple sets of balancing holes 6 are respectively distributed on the transverse water-cooled wall 14 and the longitudinal water-cooled wall 15. The number of balancing holes 6 on the transverse water-cooled wall 14 is greater than the number of balancing holes 6 on the longitudinal water-cooled wall 15.

[0032] The furnace 1 is divided into multiple combustion chambers 5 by multiple sets of longitudinal water-cooled walls 15 and transverse water-cooled walls 14, so that coal particles are mixed in multiple combustion chambers 5, and flames burn in each combustion chamber 5. With the cooperation of water-cooled walls 8 in each combustion chamber 5, as well as the first air duct 16, the second air duct 17 and the balance hole 6, the residence time of particles in the furnace 1 is increased, thereby promoting the burnout of coke. A stratified combustion mode is adopted, in which the volatile matter is burned at high temperature in the dense phase zone and the coke burnout is enhanced in the dilute phase zone, thus balancing combustion efficiency and pollutant control.

[0033] The first air duct 16 and the second air duct 17 are also provided with a mesh grid 18. The water-cooled partition wall 4 and the mesh grid 18 are both made of fire-resistant and corrosion-resistant materials, which further increases the residence time of the shell inside the furnace body.

[0034] The water-cooled wall 8 is composed of multiple sets of water-cooled rings 19, which are spaced 2-5 cm apart and interconnected.

[0035] By increasing the heat-receiving area of ​​the water-cooled ring 19, the heat exchange rate inside the water-cooled wall 8 is faster, while controlling the deviation of the heat-receiving side of the heat-receiving surface to ensure the heating effect of the water-cooled wall 8.

[0036] The cyclone separator 2 is provided in multiple sets, and the multiple sets of cyclone separator 2 are all located between the furnace 1 and the economizer 3. The bottoms of the multiple sets of cyclone separator 2 are connected by a rectifier pipe 20. The bottom of the rectifier pipe 20 is provided with a return pipe 21 that communicates with the combustion chamber 5.

[0037] The bottom of the cyclone separator 2 is also provided with a first fan 22, which is connected to the economizer 3. The first fan 22 is provided with a first air conveying pipe 23 and a second air conveying pipe 24. The air outlet of the first air conveying pipe 23 is located below the opposite side of the discharge end of the feeder 10, and the output end of the first air conveying pipe 23 faces the discharge end of the feeder 10. The second air conveying pipe 24 is located above the first air conveying pipe 23.

[0038] The first air duct 23 of the first blower 22 blows air into the lignite entering the furnace 1, causing the lignite particles to float at the bottom of the furnace 1. At the same time, the second air duct 24 simultaneously blows air into the furnace 1, allowing the lignite particles to mix fully with the oxygen in the air. Meanwhile, the air at the air inlet of the first blower 22 is preheated by the economizer 3. This can be achieved by connecting the air inlet duct of the first blower 22 through the economizer 3, thereby preheating the air inside the duct. This allows the air sent into the furnace 1 to dry the floating coal particles, reducing their moisture content. To ensure safety, the air inlet rate should be appropriately controlled.

[0039] The outer wall of the furnace 1 is also provided with an air supply ring 25. The first blower 22 is provided with a second blower 26. The second blower 26 is provided with a third air supply pipe 27. One end of the third air supply pipe 27 is connected to the air supply ring 25. The inner side of the air supply ring 25 is connected to multiple sets of combustion chambers 5. The return pipe 21 is set through the third air supply pipe 27. When the second blower 26 is working, it supplies air to multiple combustion chambers 5, thereby increasing the combustion effect inside each combustion chamber 5 and further increasing the burnout effect of coke.

[0040] The combustion method using the above-mentioned high-efficiency lignite combustion device based on high-altitude environment includes the following:

[0041] S1. Lignite enters the furnace 1 through the feeder 10. The first air pipe 23 of the first blower 22 blows air into the lignite entering the furnace 1, causing the lignite particles to float at the bottom of the furnace 1. At the same time, the second air pipe 24 blows air into the furnace 1, so that the lignite particles can be fully mixed with the oxygen in the air. Meanwhile, the air at the air inlet of the first blower 22 is preheated by the economizer 3, so that the air sent into the furnace 1 dries the flying coal particles and reduces the moisture of the coal particles. Then the burner 11 is ignited.

[0042] S2. The water-cooled partition wall 4 divides the interior of the furnace 1 into multiple combustion chambers 5. The flames and flue gas after combustion enter the multiple combustion chambers 5 respectively. At the same time, the second fan 26 works to deliver air to the multiple combustion chambers 5 respectively, thereby increasing the combustion effect inside each combustion chamber 5. The water-cooled partition wall 4 is also equipped with a connecting channel and a balance hole 6 to ensure the uniformity of gas-solid flow in each combustion chamber 5 inside the furnace 1, and to increase the residence time of coal particles inside the furnace 1.

[0043] S3. At the same time, each combustion chamber 5 is equipped with a water-cooled wall 8 as a heat-receiving component. The water-cooled wall 8 is composed of multiple sets of spaced water-cooled rings 19, thereby increasing the contact between each set of water-cooled rings 19 and the flame, thereby controlling the deviation of the heat-receiving side of the heat-receiving surface and ensuring the heating effect of the water-cooled wall 8.

[0044] S4. Cyclone separator 2 separates the particles in the flue gas. The flue gas is sent to economizer 3 for preheating and utilization, while the shell is sent back into the furnace 1 for circulating combustion.

[0045] After the water-cooled wall 8 is heated, the internal cold water boils and evaporates into steam, which is then separated and processed by the steam-liquid treatment chamber 7. The steam is then transported to the steam turbine, while the liquid is cooled and recycled.

[0046] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed. The scope of protection of the present invention is defined by the appended claims and their equivalents.

Claims

1. A high-efficiency lignite combustion device based on high-altitude environment, comprising a furnace (1), a cyclone separator (2) in communication with the dilute phase zone inside the furnace (1), and an economizer (3) for recycling flue gas waste heat, characterized in that: The inside of the furnace (1) is provided with a water-cooled partition wall (4), which divides the inside of the furnace (1) into a plurality of combustion chambers (5), the water-cooled partition wall (4) is provided with a communication air duct for the mutual communication between the plurality of combustion chambers (5), the water-cooled partition wall (4) is also provided with a balance hole (6) for ensuring the uniformity of gas-solid flow between the plurality of combustion chambers (5), the top of the furnace (1) is provided with a steam-liquid treatment bin (7) for transporting and processing steam and liquid, a plurality of water-cooled walls (8) are arranged in the plurality of combustion chambers (5), the input end and the output end of the water-cooled wall (8) are communicated with the steam-liquid treatment bin (7), a plurality of screen superheaters (9) are arranged in the dilute phase zone of the plurality of combustion chambers (5), the input end and the output end of the screen superheater (9) are communicated with the steam-liquid treatment bin (7), the dense phase zone of the furnace (1) is provided with a coal feeder (10), the lower portion of the coal feeder (10) is provided with a burner (11), the bottom of the furnace (1) is provided with a slag discharge port (12), the bottom of the economizer (3) is provided with a smoke exhaust pipe (13). The water-cooled partition wall (4) comprises a transverse water-cooled wall (14) and a plurality of longitudinal water-cooled walls (15), the transverse water-cooled wall (14) is provided with one group, the plurality of longitudinal water-cooled walls (15) are provided with a plurality of groups, and the plurality of longitudinal water-cooled walls (15) are vertically arranged between the transverse water-cooled wall (14). The communication air duct comprises a first air duct (16) and a second air duct (17), the first air duct (16) is arranged on the transverse water-cooled wall (14), the second air duct (17) is arranged on the longitudinal water-cooled wall (15), and the positions of the first air duct (16) and the second air duct (17) are staggered. The balance hole (6) is provided with a plurality of groups, and the plurality of groups of balance holes (6) are respectively arranged on the transverse water-cooled wall (14) and the longitudinal water-cooled wall (15), the number of balance holes (6) on the transverse water-cooled wall (14) is greater than that on the longitudinal water-cooled wall (15). The first air duct (16) and the second air duct (17) are further provided with a mesh grid (18). The bottom of the cyclone separator (2) is further provided with a first fan (22), and the first fan (22) is respectively provided with a first air conveying pipe (23) and a second air conveying pipe (24). The outer wall of the furnace (1) is further provided with an air supply ring (25), the first fan (22) is provided with a second fan (26), and the second fan (26) is provided with a third air conveying pipe (27).

2. A high-efficiency lignite combustion device based on high-altitude environment according to claim 1, characterized in that: The water-cooled partition wall (4) and the mesh grid (18) are made of refractory and corrosion-resistant materials.

3. A high-efficiency lignite combustion device based on high-altitude environment according to claim 2, characterized in that: The water-cooled wall (8) is composed of a plurality of water-cooled rings (19), and the plurality of water-cooled rings (19) are spaced apart by 2-5 cm and are in communication with each other.

4. A high-efficiency lignite combustion device based on high-altitude environment according to claim 3, characterized in that: The cyclone separator (2) is provided with a plurality of groups, and the plurality of groups of cyclone separators (2) are located between the furnace (1) and the economizer (3), the bottoms of the plurality of groups of cyclone separators (2) are communicated through a rectifier tube (20), and the bottom of the rectifier tube (20) is provided with a backflow pipe (21) communicated with the combustion chamber (5).

5. A high efficiency lignite combustion device based on high altitude environment as claimed in claim 4 wherein: The first fan (22) is connected with the coal economizer (3), the air outlet of the first air duct (23) is located below the opposite side of the discharge end of the coal feeder (10), the output end of the first air duct (23) is located at the discharge end of the coal feeder (10), and the second air duct (24) is located above the first air duct (23).

6. A high efficiency lignite combustion device based on high altitude environment as claimed in claim 5 wherein: One end of the third air duct (27) is communicated with the air supply ring (25), the inner side of the air supply ring (25) is communicated with a plurality of combustion chambers (5) respectively, and the backflow pipe (21) penetrates through the third air duct (27).

7. A method of combustion of the high altitude environment based lignite efficient combustion device as claimed in claim 6, wherein: The following is included; S1, the lignite enters the inside of the furnace (1) through the coal feeder (10), the first air duct (23) of the first fan (22) blows air to the lignite entering the inside of the furnace (1), so that the lignite particles float at the bottom of the furnace (1), at the same time, the second air duct (24) blows air into the furnace (1), so that the lignite particles can mix with oxygen in the air, increase the oxygen content of the fuel, and the air at the air inlet end of the first fan (22) is preheated through the coal economizer (3), so that the air entering the inside of the furnace (1) can dry the floating coal particles, reduce the moisture content of the coal particles, and increase the oxygen content in the fuel, and then the igniter (11) is ignited; S2, the water-cooled partition wall (4) divides the inside of the furnace (1) into a plurality of combustion chambers (5), the burned flame and flue gas enter the plurality of combustion chambers (5) respectively, and the second fan (26) works to respectively send air to the plurality of combustion chambers (5), so as to increase the combustion effect in each combustion chamber (5), and the water-cooled partition wall (4) is also provided with a communication passage and a balance hole (6), so as to ensure the uniformity of gas-solid flow in each combustion chamber (5) in the furnace (1), and increase the residence time of the coal particles in the furnace (1); S3, each combustion chamber (5) is provided with a water-cooled wall (8) as a heating element, and the water-cooled wall (8) is composed of a plurality of spaced water-cooled rings (19), so as to increase the contact between each group of water-cooled rings (19) and the flame, and then control the heating side deviation of the heating surface, and ensure the heating effect of the water-cooled wall (8); S4, the cyclone separator (2) separates the particles in the flue gas, the flue gas is sent into the coal economizer (3) for preheating and utilization, and the shell is sent into the furnace (1) for circulating combustion; S5, after the water-cooled wall (8) is heated, the internal cold water boils to evaporate steam, which is separated and treated through the vapor-liquid treatment bin (7), and the steam is sent to the steam turbine, and the liquid is recycled after cooling.

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