Tower type pulverized coal boiler suitable for natural circulation operation mode

Abstract

The invention discloses a tower-type pulverized coal boiler suitable for a natural circulation operation mode, and relates to the technical field of coal-fired unit power generation. In order to solve the problems that according to an existing pi-shaped arrangement mode, flue gas needs to pass through six 90-degree turns from a hearth to a boiler outlet, a flue gas flow field is not uniform, the dust accumulation situation is prone to occurring at the position of a horizontal flue, the depth (length) of a boiler is increased by 8-10 m through a tail vertical shaft flue, the overall occupied area is large, a full-hydrophobic structure cannot be achieved, and rapid starting of the boiler is not facilitated. A coal economizer, a first-stage superheater, a second-stage superheater, a third-stage superheater and a reheater are arranged in a hearth to integrally form a tower type arrangement, so that the hearth forms a membrane type water-cooled wall cavity structure, and flue gas formed after pulverized coal is combusted sequentially passes through the hearth, the superheaters, the reheater and the coal economizer to form a membrane type water-cooled wall cavity structure. Flue gas enters the denitration device, the air preheater and the boiler outlet through the connecting flue, a full-hydrophobic structure of a heating surface can be achieved, and the function of rapidly starting the boiler is achieved. The method is suitable for the coal-fired unit.

Description

Technical Field

[0001] The invention relates to the technical field of coal-fired unit power generation, and in particular to a tower-type pulverized coal boiler suitable for a natural circulation operation mode. Background Art

[0002] At present, coal-fired units are mainly composed of two parts: a coal-fired furnace and a steam turbine. The heat generated by the coal burning in the coal-fired furnace will heat the water in the boiler and turn it into high-temperature and high-pressure steam. These steams then enter the steam turbine to drive the turbine to rotate, thereby generating power, and are mainly used for industrial steam, heat, electricity, etc., generally with parameters below ultra-high pressure, using a natural circulation operation mode with a steam drum, and the boiler layout is π-type. The boiler is equipped with a horizontal flue and a tail shaft flue. The existing π-type layout requires the flue gas to pass through 6 90-degree turns from the furnace to the boiler outlet. The flue gas flow field is uneven, and ash is prone to accumulation at the horizontal flue. The tail shaft flue increases the depth (length) of the boiler by 8 to 10 meters, and the overall footprint is large. It is impossible to achieve a fully drained structure, which is not conducive to the problem of rapid boiler startup. Summary of the invention

[0003] The present invention aims to solve the problems that in the existing π-type arrangement, the flue gas needs to pass through 6 90-degree turns from the furnace to the boiler outlet, the flue gas flow field is uneven, and ash is easily accumulated in the horizontal flue. The tail vertical shaft flue increases the depth (length) of the boiler by 8 to 10 meters, the overall floor area is large, and a full drainage structure cannot be achieved, which is not conducive to the rapid start-up of the boiler. A tower-type pulverized coal boiler suitable for natural circulation operation is proposed.

[0004] A tower-type pulverized coal boiler suitable for natural circulation operation of the present invention comprises a steam drum 1, a downcomer 2, a dispersed inlet pipe 3, a water-cooled wall lower header 4, a furnace 5, a water-cooled wall upper header 6, a steam-water outlet pipe 7, a saturated steam outlet pipe 8, an economizer 9, a primary superheater 10, a secondary superheater 11, a tertiary superheater 12, a reheater 13, a connecting flue 14, a denitrification device 15, an air preheater 16 and a boiler outlet flue 17;

[0005] The economizer 9, reheater 13, primary superheater 10, tertiary superheater 12 and secondary superheater 11 are sequentially arranged inside the furnace 5 from top to bottom. The top of the furnace 5 is provided with a water-cooled wall upper header 6, and the water-cooled wall upper header 6 is provided with a steam-water outlet pipe 7. The generated steam-water mixture can enter the steam drum 1 through the steam-water outlet pipe 7. The steam drum 1 is provided with a saturated steam outlet pipe 8. The end of the saturated steam outlet pipe 8 is connected to the inlet header of the primary superheater 10. The lower part of the steam drum 1 is connected to the lower The top end of the downcomer 2 is connected, the bottom end of the downcomer 2 is connected to one end of the dispersion introduction pipe 3, the other end of the dispersion introduction pipe 3 is connected to the input end of the water-cooled wall lower header 4, and the water-cooled wall lower header 4 is fixed to the bottom surface of the furnace 5, the flue gas outlet of the economizer 9 is connected to the input end of the denitrification device 15 through the connecting flue 14, the output end of the denitrification device 15 is connected to the input end of the air preheater 16, and the output end of the air preheater 16 is connected to the top of the boiler outlet flue 17;

[0006] Furthermore, the economizer 9, the reheater 13, the primary superheater 10, the tertiary superheater 12 and the secondary superheater 11 arranged inside the furnace 5 are arranged in a tower-like manner as a whole;

[0007] Furthermore, the water-cooled wall upper header 6 is connected to the furnace 5;

[0008] Furthermore, the water-cooled wall lower header 4 is connected to the furnace 5;

[0009] Furthermore, the water-cooled wall lower header 4, the furnace 5, the water-cooled wall upper header 6, the internal economizer 9, the reheater 13, the primary superheater 10, the tertiary superheater 12 and the secondary superheater 11 are coaxially arranged;

[0010] Furthermore, the connecting flue 14 is an inclined pipe;

[0011] Furthermore, when in use, the water circulation system of the boiler is composed of the steam drum 1, the downcomer 2, the dispersed inlet pipe 3, the water wall lower header 4, the furnace 5, the water wall upper header 6, and the steam-water outlet pipe 7;

[0012] The furnace 5 is a cavity structure composed of membrane water-cooled walls, and the economizer 9, the primary superheater 10, the secondary superheater 11, the tertiary superheater 12, and the reheater 13 are placed inside the furnace 5, forming a tower arrangement as a whole;

[0013] The flue gas generated by the combustion of pulverized coal in the burner passes through the furnace 5, the secondary superheater 11, the tertiary superheater 12, the primary superheater 10, the reheater 13, and the economizer 9 in sequence. The flue gas enters the denitrification device 15 and the air preheater 16 through the connecting flue 14 again, and finally passes through the boiler outlet flue 17.

[0014] Compared with the prior art, the present invention has the following beneficial effects:

[0015] The present invention overcomes the shortcomings of the prior art and adopts an economizer, a primary superheater, a secondary superheater, a tertiary superheater and a reheater to be placed inside the furnace, forming a tower-like arrangement as a whole, so that the furnace forms a membrane-type water-cooled wall cavity structure. The flue gas formed after the combustion of coal powder passes through the furnace, the superheater (the superheater can be divided into a primary, secondary and tertiary arrangement), the reheater (the reheater-level arrangement) and the economizer in sequence. The flue gas enters the denitrification device and the air preheater to the boiler outlet through the connecting flue, which can realize the full hydrophobic structure of the heating surface and the function of quickly starting the boiler; the flue gas can flow smoothly, thereby solving the problem of ash accumulation in the horizontal flue and greatly reducing the occupied area. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a front view of a tower-type pulverized coal boiler suitable for natural circulation operation according to the present invention. DETAILED DESCRIPTION

[0017] Specific implementation method 1: Combination Figure 1 The present embodiment is described. The tower-type pulverized coal boiler suitable for natural circulation operation described in the present embodiment comprises a steam drum 1, a downcomer 2, a dispersed inlet pipe 3, a water-cooled wall lower header 4, a furnace 5, a water-cooled wall upper header 6, a steam-water outlet pipe 7, a saturated steam outlet pipe 8, an economizer 9, a primary superheater 10, a secondary superheater 11, a tertiary superheater 12, a reheater 13, a connecting flue 14, a denitrification device 15, an air preheater 16 and a boiler outlet flue 17;

[0018] The economizer 9, reheater 13, primary superheater 10, tertiary superheater 12 and secondary superheater 11 are sequentially arranged inside the furnace 5 from top to bottom. The top of the furnace 5 is provided with a water-cooled wall upper header 6, and the water-cooled wall upper header 6 is provided with a steam-water outlet pipe 7. The generated steam-water mixture can enter the steam drum 1 through the steam-water outlet pipe 7. The steam drum 1 is provided with a saturated steam outlet pipe 8. The end of the saturated steam outlet pipe 8 is connected to the inlet header of the primary superheater 10. The lower part of the steam drum 1 is connected to the lower The top end of the downcomer 2 is connected, the bottom end of the downcomer 2 is connected to one end of the dispersion introduction pipe 3, the other end of the dispersion introduction pipe 3 is connected to the input end of the water-cooled wall lower header 4, and the water-cooled wall lower header 4 is fixed to the bottom surface of the furnace 5, the flue gas outlet of the economizer 9 is connected to the input end of the denitrification device 15 through the connecting flue 14, the output end of the denitrification device 15 is connected to the input end of the air preheater 16, and the output end of the air preheater 16 is connected to the top of the boiler outlet flue 17;

[0019] In this specific embodiment, when in use, the water circulation system of the boiler is composed of the steam drum 1, the downcomer 2, the dispersed inlet pipe 3, the water wall lower header 4, the furnace 5, the water wall upper header 6, and the steam-water outlet pipe 7;

[0020] The furnace 5 is a cavity structure composed of membrane water-cooled walls, and the economizer 9, the primary superheater 10, the secondary superheater 11, the tertiary superheater 12, and the reheater 13 are placed inside the furnace 5, forming a tower arrangement as a whole;

[0021] The flue gas generated by the combustion of pulverized coal in the burner passes through the furnace 5, the secondary superheater 11, the tertiary superheater 12, the primary superheater 10, the reheater 13, and the economizer 9 in sequence. The flue gas enters the denitrification device 15 and the air preheater 16 through the connecting flue 14 again, and finally passes through the boiler outlet flue 17.

[0022] Specific implementation method 2: Combination Figure 1 The present embodiment is described as a further limitation of the boiler described in the first specific embodiment. The present embodiment is a tower-type pulverized coal boiler suitable for natural circulation operation, wherein the economizer 9, the reheater 13, the first-stage superheater 10, the third-stage superheater 12 and the second-stage superheater 11 are arranged inside the furnace 5, and the whole is arranged in a tower shape.

[0023] Specific implementation method three: Combination Figure 1 This embodiment is described as a further limitation of the boiler described in the first embodiment. This embodiment is a tower-type pulverized coal boiler suitable for natural circulation operation, in which the interior of the water-cooled wall upper header 6 is connected to the interior of the furnace 5.

[0024] Specific implementation method four: Combination Figure 1 This embodiment is described as a further limitation of the boiler described in the third embodiment. This embodiment is a tower-type pulverized coal boiler suitable for natural circulation operation, in which the water-cooled wall lower header 4 is connected to the furnace 5.

[0025] Specific implementation method five: Combination Figure 1 The present embodiment is described. The present embodiment is a further limitation on the boiler described in the first specific embodiment. The present embodiment describes a tower-type pulverized coal boiler suitable for natural circulation operation, wherein the water-cooled wall lower header 4, the furnace 5, the water-cooled wall upper header 6, the internal economizer 9, the reheater 13, the primary superheater 10, the tertiary superheater 12 and the secondary superheater 11 are coaxially arranged.

[0026] Specific implementation method six: Combination Figure 1 This embodiment is described as a further limitation of the boiler described in the first embodiment. This embodiment is a tower-type pulverized coal boiler suitable for natural circulation operation, and the connecting flue 14 is an inclined pipe.

[0027] How it works

[0028] When in use, the water circulation system of the boiler is composed of the steam drum 1, the downcomer 2, the dispersed inlet pipe 3, the lower header of the water-cooled wall 4, the furnace 5, the upper header of the water-cooled wall 6, and the steam-water outlet pipe 7;

[0029] The furnace 5 is a cavity structure composed of membrane water-cooled walls, and the economizer 9, the primary superheater 10, the secondary superheater 11, the tertiary superheater 12, and the reheater 13 are placed inside the furnace 5, forming a tower arrangement as a whole;

[0030] The flue gas generated by the combustion of pulverized coal in the burner passes through the furnace 5, the secondary superheater 11, the tertiary superheater 12, the primary superheater 10, the reheater 13, and the economizer 9 in sequence. The flue gas enters the denitrification device 15 and the air preheater 16 through the connecting flue 14 again, and finally passes through the boiler outlet flue 17.

Claims

1. A tower-type pulverized coal boiler suitable for natural circulation operation, characterized in that: It comprises a steam drum (1), a downcomer (2), a dispersed inlet pipe (3), a water-cooled wall lower header (4), a furnace (5), a water-cooled wall upper header (6), a steam-water outlet pipe (7), a saturated steam outlet pipe (8), an economizer (9), a primary superheater (10), a secondary superheater (11), a tertiary superheater (12), a reheater (13), a connecting flue (14), a denitrification device (15), an air preheater (16) and a boiler outlet flue (17); The economizer (9), reheater (13), primary superheater (10), tertiary superheater (12) and secondary superheater (11) are sequentially arranged inside the furnace (5) from top to bottom. A water-cooled wall upper header (6) is provided at the top of the furnace (5). The water-cooled wall upper header (6) is provided with a steam-water outlet pipe (7). The generated steam-water mixture can enter the steam drum (1) through the steam-water outlet pipe (7). The steam drum (1) is provided with a saturated steam outlet pipe (8). The end of the saturated steam outlet pipe (8) is connected to the inlet header of the primary superheater (10). The lower portion of the steam drum (1) is provided with a saturated steam outlet pipe (8). The down pipe (2) is connected to the top end of the down pipe (2), the bottom end of the down pipe (2) is connected to one end of the dispersed introduction pipe (3), the other end of the dispersed introduction pipe (3) is connected to the input end of the water-cooled wall lower header (4), and the water-cooled wall lower header (4) is fixed to the bottom surface of the furnace (5), the flue gas outlet of the economizer (9) is connected to the input end of the denitrification device (15) through the connecting flue (14), the output end of the denitrification device (15) is connected to the input end of the air preheater (16), and the output end of the air preheater (16) is connected to the top end of the boiler outlet flue (17).

2. A tower-type pulverized coal boiler suitable for natural circulation operation according to claim 1, characterized in that: The furnace (5) is internally arranged with an economizer (9), a reheater (13), a primary superheater (10), a tertiary superheater (12) and a secondary superheater (11), which are arranged in a tower-like manner as a whole.

3. A tower-type pulverized coal boiler suitable for natural circulation operation according to claim 1, characterized in that: The water-cooled wall upper header (6) is connected to the furnace (5).

4. A tower-type pulverized coal boiler suitable for natural circulation operation according to claim 3, characterized in that: The water-cooled wall lower header (4) is connected to the furnace (5).

5. A tower-type pulverized coal boiler suitable for natural circulation operation according to claim 1, characterized in that: The water-cooled wall lower header (4), the furnace (5), the water-cooled wall upper header (6), the internal economizer (9), the reheater (13), the first-stage superheater (10), the third-stage superheater (12) and the second-stage superheater (11) are coaxially arranged.

6. A tower-type pulverized coal boiler suitable for natural circulation operation according to claim 1, characterized in that: The connecting flue (14) is an inclined pipe.

Images