600MW-grade ultra-supercritical tower type liquid deslagging boiler

Abstract

The invention discloses a 600MW-grade ultra-supercritical tower type liquid deslagging boiler, and relates to a liquid deslagging boiler. The problems that in the prior art, when Zhundong coal is combusted in a solid-state deslagging boiler, serious coking and contamination occur, and then the boiler cannot stably operate are solved. By adopting a liquid deslagging technology, the defects of serious coking and contamination when Zhundong coal is combusted in an existing solid deslagging technology are overcome, and by adopting the double combustion chambers with high combustion heat intensity and a W-shaped combustion structure and coating refractory castable, heat absorption of a water cooling wall is reduced, the temperature in the combustion chambers is increased, ash slag is completely melted, the slag catching rate is increased, and the energy consumption is reduced. Dust content of smoke at a hearth outlet is reduced, and slag bonding and contamination of the hearth and other heating surfaces are prevented. The Zhundong coal with extremely high coking property or other coal types with low ash fusion point can be combusted completely, a key role is played in large-scale development and utilization of the Zhundong coal, and the economic benefit and sustainable development of a power plant are improved. The invention belongs to the technical field of liquid deslagging boilers.

Description

Technical Field

[0001] The invention relates to a liquid slag discharge boiler, in particular to a 600MW-level ultra-supercritical tower-type liquid slag discharge boiler, and belongs to the technical field of liquid slag discharge boilers. Background Art

[0002] my country's Zhundong coalfield has rich reserves, but the alkali metal content of Zhundong coal is high, and there are serious slagging and contamination problems. The existing boilers burning Zhundong coal are all solid slagging boilers. Burning Zhundong coal has caused varying degrees of slagging and contamination. After the slag falls off, it often damages the water-cooled wall of the cold ash hopper; and the slag removal system frequently fails to operate and the flue is blocked, and in serious cases, the boiler is forced to shut down.

[0003] Liquid slag discharge boilers have a high slag capture rate and can capture most of the low-melting-point alkali metal components into the slag, reducing the ash content in the flue gas, especially reducing the content of alkali metal substances, and preventing coking and fouling of the furnace and heating surfaces. The liquid slag discharge method is an effective way to solve the coking and fouling problems when the boiler burns strong coking coal such as Zhundong coal, but my country has no application and experience in high-parameter and large-capacity liquid slag discharge boilers.

[0004] In summary, how to propose a new liquid slag discharge boiler to address the above technical problems has become an urgent problem to be solved by technicians in this field. Summary of the invention

[0005] In view of the above-mentioned deficiencies in the prior art, the present invention provides a 600MW-class ultra-supercritical tower-type liquid slag discharge boiler.

[0006] The technical solution of the present invention is: a 600MW ultra-supercritical tower type liquid slag discharge boiler comprises a lower cooling chamber, an upper cooling chamber, a vertical flue, a horizontal flue, a steam-water separator and two U-shaped combustion chambers.

[0007] A plurality of tertiary air nozzles are provided on the U-shaped combustion chamber, a plurality of swirl burners are installed at the entrance of the U-shaped combustion chamber, a slag catching screen is installed at the outlet of the U-shaped combustion chamber, a slag bucket is installed at the bottom of the U-shaped combustion chamber, and a liquid slag discharge port is installed at the bottom of the slag bucket.

[0008] The two U-shaped combustion chambers are arranged symmetrically, and the outlets of the two U-shaped combustion chambers are connected to the lower cooling chamber. The two U-shaped combustion chambers and the lower cooling chamber form a W-shaped combustion structure, and a W-shaped water-cooled wall is installed in the W-shaped combustion structure.

[0009] A plurality of fourth-order air nozzles are provided on the lower cooling chamber, and a smoke folding arch is integrally arranged at the bottom of the lower cooling chamber.

[0010] The upper cooling chamber is arranged above the lower cooling chamber, and a screen superheater, a final superheater and a final reheater are arranged in sequence in the upper cooling chamber according to the flow direction of the flue gas.

[0011] The vertical flue is arranged above the upper cooling chamber. The vertical flue includes a flue gas regulating baffle, a first flue and a second flue. The first flue and the second flue are arranged in parallel. The flue gas regulating baffle is arranged at the outlet of the vertical flue.

[0012] A secondary superheater and an economizer are arranged in sequence in the first flue according to the flow direction of the flue gas, and a low-temperature reheater and an economizer are arranged in sequence in the second flue according to the flow direction of the flue gas.

[0013] The water-cooled wall inlet of the upper cooling chamber is communicated with the outlet of the W-shaped water-cooled wall, and the water-cooled wall outlet of the upper cooling chamber is communicated with the inlet of the steam-water separator.

[0014] The inlet of the screen superheater is connected to the outlet of the steam-water separator, and the outlet of the screen superheater is connected to the inlet of the secondary superheater.

[0015] The inlet of the final superheater is connected to the outlet of the secondary superheater, and the inlet of the final reheater is connected to the outlet of the low-temperature reheater.

[0016] The outlet of the final superheater, the outlet of the final reheater and the inlet of the low-temperature reheater are all connected to the steam turbine.

[0017] The inlet of the economizer is connected to the boiler feed water system, and the outlet of the economizer is connected to the inlet of the W-shaped water-cooled wall.

[0018] The horizontal flue is arranged above the vertical flue, and the outlet of the vertical flue is communicated with the horizontal flue.

[0019] Compared with the prior art, the present invention has the following effects:

[0020] 1. The present invention adopts liquid slag removal technology, which overcomes the shortcomings of serious coking and contamination when burning Zhundong coal in the existing solid slag removal technology. By adopting a double combustion chamber with high combustion heat intensity and a W-shaped combustion structure and coating refractory castables, the water-cooled wall absorbs heat, the temperature in the combustion chamber is increased, the ash and slag are completely melted, the slag capture rate is increased, the dust content of the flue gas at the furnace outlet is reduced, and the furnace and other heating surfaces are prevented from slagging and contamination. The ability to burn 100% of Zhundong coal with extremely strong coking properties or other coal types with low ash melting points plays a key role in the large-scale development and utilization of Zhundong coal, and improves the economic benefits and sustainable development of power plants.

[0021] 2. The present invention is a 600MW-class ultra-supercritical boiler with a main steam flow rate of 1930-2100 t / h, a main steam pressure of 28.2-29.3 MPa, a main steam temperature of 605°C, and a reheat steam temperature of 613-623°C. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 is a first schematic diagram of the present invention;

[0023] Figure 2 It is a second schematic diagram of the present invention.

[0024] In the figure: 1. U-shaped combustion chamber; 1-1. slag hopper; 1-2. liquid slag discharge port; 2. swirl burner; 3. tertiary air nozzle; 4. quaternary air nozzle; 5. slag catcher; 6. lower cooling chamber; 6-1. smoke folding arch; 7. upper cooling chamber; 7-1. spiral water-cooled wall; 7-2. vertical water-cooled wall; 8. screen superheater; 9. final superheater; 10. final reheater; 11. secondary superheater; 12. low-temperature reheater; 13. economizer; 14. preheater; 15. steam-water separator; 16. first flue; 17. second flue; 18. horizontal flue; 19. third flue. DETAILED DESCRIPTION

[0025] In order to make the purpose, features and advantages of the present invention more obvious and understandable, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention.

[0026] Specific implementation method 1: Combination Figure 1 and Figure 2 The present embodiment is described as a 600MW-class ultra-supercritical tower-type liquid slag discharge boiler, which includes a lower cooling chamber 6, an upper cooling chamber 7, a vertical flue, a horizontal flue 18, a steam-water separator 15 and two U-shaped combustion chambers 1.

[0027] A plurality of tertiary air nozzles 3 are provided on the U-shaped combustion chamber 1. Such arrangement can realize staged combustion of the fuel and supplement the air required in the middle stage of combustion. A plurality of swirl burners 2 are installed at the entrance of the U-shaped combustion chamber 1. The swirl burner 2 burns the fuel in the U-shaped combustion chamber 1 by vertical downward combustion. Such arrangement is conducive to ensuring a high degree of flame fullness in the U-shaped combustion chamber 1. The center of the flame is close to the bottom of the U-shaped combustion chamber 1, which increases the bottom temperature and helps to ensure the fluidity of the bottom slag. A slag screen 5 is installed at the outlet of the U-shaped combustion chamber 1. Such arrangement allows the slag screen 5 to capture the liquid slag carried in the flue gas and improve the slag capture rate of the liquid slag discharge boiler. A slag hopper 1-1 is installed at the bottom of the U-shaped combustion chamber 1, and a liquid slag discharge port 1-2 is installed at the bottom of the slag hopper 1-1.

[0028] The two U-shaped combustion chambers 1 are arranged symmetrically, and the outlets of the two U-shaped combustion chambers 1 are connected to the lower cooling chamber 6. The two U-shaped combustion chambers 1 and the lower cooling chamber 6 form a W-shaped combustion structure. This arrangement increases the separation effect of liquid slag, is beneficial to improving the slag capture rate, reduces the dust content of the flue gas at the outlet of the U-shaped combustion chamber 1, and prevents slagging on the heating surface. A W-shaped water-cooled wall is installed in the W-shaped combustion structure.

[0029] A plurality of quaternary air nozzles 4 are provided on the lower cooling chamber 6 to supplement the air required in the later stage of combustion, improve the burnout rate of the fuel, reduce the amount of excess air in the U-shaped combustion chamber 1, and further increase the combustion temperature of the combustion chamber; a smoke folding arch 6-1 is integrally provided at the bottom of the lower cooling chamber 6, so that the smoke at the outlet of the U-shaped combustion chamber 1 is deflected, thereby accelerating the capture and separation of the liquid slag.

[0030] The upper cooling chamber 7 is arranged above the lower cooling chamber 6. In the upper cooling chamber 7, a platen superheater 8, a final superheater 9 and a final reheater 10 are arranged in sequence according to the flow direction of the flue gas.

[0031] The vertical flue is arranged above the upper cooling chamber 7, and includes a smoke regulating baffle, a first flue 16 and a second flue 17. The first flue 16 and the second flue 17 are arranged in parallel, and the smoke regulating baffle is arranged at the outlet of the vertical flue.

[0032] A secondary superheater 11 and an economizer 13 are arranged in sequence in the first flue 16 according to the flow direction of the flue gas, and a low-temperature reheater 12 and an economizer 13 are arranged in sequence in the second flue 17 according to the flow direction of the flue gas. Such an arrangement is conducive to the settling of fly ash and reduces ash blockage or wear of the heating surface. Furthermore, the heating surfaces of the screen superheater 8, the final superheater 9, the final reheater 10, the secondary superheater 11, the low-temperature reheater 12 and the economizer 13 are all arranged horizontally. When the boiler is shut down, the working fluid can completely flow out of the heating surface to prevent internal corrosion or oxide scale accumulation of the heating surface.

[0033] The water-cooled wall inlet of the upper cooling chamber 7 is communicated with the outlet of the W-shaped water-cooled wall, and the water-cooled wall outlet of the upper cooling chamber 7 is communicated with the inlet of the steam-water separator 15 .

[0034] The inlet of the platen superheater 8 is communicated with the outlet of the steam-water separator 15 , and the outlet of the platen superheater 8 is communicated with the inlet of the secondary superheater 11 .

[0035] The inlet of the final stage superheater 9 is connected to the outlet of the secondary superheater 11 , and the inlet of the final stage reheater 10 is connected to the outlet of the low-temperature reheater 12 .

[0036] The outlet of the final superheater 9, the outlet of the final reheater 10 and the inlet of the low-temperature reheater 12 are all connected to the steam turbine.

[0037] The inlet of the economizer 13 is connected to the boiler feed water system, and the outlet of the economizer 13 is connected to the inlet of the W-shaped water-cooled wall.

[0038] The horizontal flue 18 is arranged above the vertical flue, and the outlet of the vertical flue is connected to the horizontal flue 18 .

[0039] Specific implementation method 2: Combination Figure 1 and Figure 2 The present embodiment will be described. In the present embodiment, the upper cooling chamber 7 includes a spiral water-cooled wall 7 - 1 and a vertical water-cooled wall 7 - 2 .

[0040] The inlet of the spiral water-cooled wall 7-1 is connected to the outlet of the W-shaped water-cooled wall.

[0041] The outlet of the spiral water-cooled wall 7 - 1 is connected to the inlet of the vertical water-cooled wall 7 - 2 , and the outlet of the vertical water-cooled wall 7 - 2 is connected to the inlet of the steam-water separator 15 .

[0042] Other components and connection relationships are the same as those in the first specific implementation method.

[0043] Specific implementation method three: Combination Figure 1 and Figure 2 To explain this embodiment, in this embodiment, third flues 19 are vertically installed at both ends of the horizontal flue 18 , and a preheater 14 is installed at the outlet of the third flue 19 .

[0044] The outlet of the third flue 19 points to the horizontal plane. With this arrangement, the vertical flue, the horizontal flue 18 and the third flue 19 form an M-shaped flue structure, which is conducive to symmetrical extraction of smoke and reduces smoke deviation.

[0045] The other components and connection relationships are the same as those in the first or second specific implementation.

[0046] Specific implementation method four: Combination Figure 1 and Figure 2 To explain this embodiment, in this embodiment, the W-shaped water-cooled wall and the wall surface of the lower cooling chamber 6 are coated with refractory castables. Furthermore, silicon carbide refractory castables are selected. In this way, the temperature in the U-shaped combustion chamber 1 is increased. When the boiler is running, the average combustion temperature in the U-shaped combustion chamber 1 exceeds 1600°C, and the smoke temperature at the outlet of the U-shaped combustion chamber 1 exceeds 1500°C. The high temperature melts the ash after the coal is burned to form liquid slag. Under the action of the airflow, the liquid slag is thrown onto the W-shaped water-cooled wall of the U-shaped combustion chamber 1 to form a layer of liquid slag film. The liquid slag flows downward along the wall surface of the water-cooled wall to the slag hopper 1-1, and is finally discharged from the liquid slag discharge port 1-2.

[0047] The other components and connection relationships are the same as those of the first, second or third specific implementation modes.

[0048] Specific implementation method five: Combination Figure 1 and Figure 2 To explain this embodiment, the number of swirl burners 2 in this embodiment is 20 to 32, and a coal mill is used to provide fuel for the swirl burners 2. Other components and connection relationships are the same as those in the first, second, third or fourth embodiment.

[0049] How it works

[0050] The outlets of the two U-shaped combustion chambers 1 are both connected to the lower cooling chamber 6, the upper cooling chamber 7 is arranged above the lower cooling chamber 6, the vertical flue is arranged above the upper cooling chamber 7, the horizontal flue 18 is arranged above the vertical flue, and the third flue 19 is vertically installed at both ends of the horizontal flue 18.

[0051] The flue gas in the U-shaped combustion chamber 1 flows through the lower cooling chamber 6, the upper cooling chamber 7, the vertical flue, the horizontal flue 18 and the third flue 19 in sequence and then is discharged from the boiler.

[0052] A plurality of swirl burners 2 are installed at the entrance of the U-shaped combustion chamber 1. The swirl burners 2 use a vertical downward combustion method to burn the fuel in the U-shaped combustion chamber 1. The U-shaped combustion chamber 1 is provided with a plurality of tertiary air nozzles 3 to achieve staged combustion of the fuel and supplement the air required in the middle stage of combustion. A slag catching screen 5 is installed at the outlet of the U-shaped combustion chamber 1. The slag catching screen 5 can capture the liquid slag carried in the flue gas and improve the slag catching rate of the liquid slag discharge boiler. A slag hopper is installed at the bottom of the U-shaped combustion chamber 1. 1-1, a liquid slag discharge port 1-2 is installed at the bottom of the slag hopper 1-1; a plurality of quaternary air nozzles 4 are opened on the lower cooling chamber 6 to supplement the air required in the late stage of combustion, and a smoke folding arch 6-1 is integrally arranged at the bottom of the lower cooling chamber 6 to turn the flue gas at the outlet of the U-shaped combustion chamber 1, accelerate the capture and separation of liquid slag, thereby capturing most of the low-melting-point alkali metal components into the molten slag, preventing the combustion chamber and the heating surface from coking and slagging, avoiding damage to the water-cooled wall, and making the boiler run stably.

[0053] The present invention has been disclosed as above in the form of a preferred embodiment, but it is not intended to limit the present invention. Any simple modification, equivalent changes and modifications made to the above implementation cases by any professional and technical personnel who do not deviate from the content of the technical solution of the present invention and based on the technical essence of the present invention are still within the scope of the technical solution of the present invention.

Claims

1. A 600MW ultra-supercritical tower type liquid slag discharge boiler, characterized in that: It comprises a lower cooling chamber (6), an upper cooling chamber (7), a vertical flue, a horizontal flue (18), a steam-water separator (15) and two U-shaped combustion chambers (1); A plurality of tertiary air nozzles (3) are provided on the U-shaped combustion chamber (1), a plurality of swirl burners (2) are installed at the entrance of the U-shaped combustion chamber (1), a slag catching screen (5) is installed at the exit of the U-shaped combustion chamber (1), a slag bucket (1-1) is installed at the bottom of the U-shaped combustion chamber (1), and a liquid slag discharge port (1-2) is installed at the bottom of the slag bucket (1-1); The two U-shaped combustion chambers (1) are symmetrically arranged, and the outlets of the two U-shaped combustion chambers (1) are both connected to the lower cooling chamber (6). The two U-shaped combustion chambers (1) and the lower cooling chamber (6) form a W-shaped combustion structure, and a W-shaped water-cooled wall is installed in the W-shaped combustion structure; A plurality of quaternary air nozzles (4) are provided on the lower cooling chamber (6), and a smoke folding arch (6-1) is integrally provided at the bottom of the lower cooling chamber (6); The upper cooling chamber (7) is arranged above the lower cooling chamber (6), and a platen superheater (8), a final superheater (9) and a final reheater (10) are arranged in sequence in the upper cooling chamber (7) according to the flow direction of the flue gas; The vertical flue is arranged above the upper cooling chamber (7), the vertical flue comprises a flue gas regulating baffle, a first flue (16) and a second flue (17), the first flue (16) and the second flue (17) are arranged in parallel, and the flue gas regulating baffle is arranged at the outlet of the vertical flue; A secondary superheater (11) and an economizer (13) are arranged in sequence in the first flue (16) according to the flow direction of the flue gas, and a low-temperature reheater (12) and an economizer (13) are arranged in sequence in the second flue (17) according to the flow direction of the flue gas; The water-cooled wall inlet of the upper cooling chamber (7) is communicated with the outlet of the W-shaped water-cooled wall, and the water-cooled wall outlet of the upper cooling chamber (7) is communicated with the inlet of the steam-water separator (15); The inlet of the platen superheater (8) is connected to the outlet of the steam-water separator (15), and the outlet of the platen superheater (8) is connected to the inlet of the secondary superheater (11); The inlet of the final superheater (9) is connected to the outlet of the secondary superheater (11), and the inlet of the final reheater (10) is connected to the outlet of the low-temperature reheater (12); The outlet of the final superheater (9), the outlet of the final reheater (10) and the inlet of the low-temperature reheater (12) are all connected to the steam turbine; The inlet of the economizer (13) is connected to the boiler feed water system, and the outlet of the economizer (13) is connected to the inlet of the W-shaped water-cooled wall; The horizontal flue (18) is arranged above the vertical flue, and the outlet of the vertical flue is connected to the horizontal flue (18).

2. A 600MW ultra-supercritical tower type liquid slag discharge boiler according to claim 1, characterized in that: The upper cooling chamber (7) comprises a spiral water-cooling wall (7-1) and a vertical water-cooling wall (7-2); The inlet of the spiral water-cooled wall (7-1) is connected to the outlet of the W-shaped water-cooled wall, the outlet of the spiral water-cooled wall (7-1) is connected to the inlet of the vertical water-cooled wall (7-2), and the outlet of the vertical water-cooled wall (7-2) is connected to the inlet of the steam-water separator (15).

3. A 600MW grade ultra-supercritical tower type liquid slag discharge boiler according to claim 2, characterized in that: A third flue (19) is vertically installed at both ends of the horizontal flue (18), and a preheater (14) is installed at the outlet of the third flue (19).

4. A 600MW ultra-supercritical tower type liquid slag discharge boiler according to claim 3, characterized in that: The outlet of the third flue (19) points to the horizontal plane.

5. The 600MW ultra-supercritical tower type liquid slag discharge boiler according to claim 1, characterized in that: The W-shaped water-cooled wall and the wall surface of the lower cooling chamber (6) are both coated with refractory castables.

6. A 600MW ultra-supercritical tower type liquid slag discharge boiler according to claim 1, characterized in that: The number of the swirl burners (2) is 20 to 32.

Images