Secondary reheating boiler type with three gas flues arranged at tail part

Abstract

The invention discloses a secondary reheating boiler type with three gas flues arranged at a tail part, and belongs to the field of power station boilers. The secondary reheating boiler type with the three gas flues arranged at the tail part comprises a tail part gas flue; the tail part gas flue is divided into a front gas flue, a middle gas flue and a rear gas flue; each of the front gas flue and the middle gas flue is provided with a low-temperature re-heater vertical section, a low-temperature re-heater horizontal section, an economizer and a flue gas adjusting baffle in sequence in a flue gas direction; the rear gas flue is provided with a hot secondary air heater, an economizer and a flue gas adjusting baffle in sequence in the flue gas direction; a hot secondary air outlet of an air pre-heater is communicated with a hot secondary air inlet of the hot secondary air heater; the hot secondary air outlet of the hot secondary air heater is communicated with a hearth. According to the secondary reheating boiler type with the three gas flues arranged at the tail part, the requirements on balancing primary and secondary low resorbent heat, regulating a reheating steam temperature and matching the resistance of the flue gas among the three gas flues are met; the absorbed heat of the economizers is reduced to prevent the economizers from vaporizing; the temperature of exhaust gas is decreased; the boiler efficiency is improved; the coal consumption of a machine set is reduced.

Description

technical field

[0001] The invention belongs to the field of power station boilers. Background technique

[0002] In the existing secondary reheat boiler with three flues at the rear, three heating surfaces of primary low reheat, secondary low reheat and low temperature superheater are usually arranged in the three flues at the rear. However, with the improvement of boiler steam parameters, the low superheat absorption accounts for a small proportion of the superheater system heat absorption (taking the 630℃ secondary reheat parameter project as an example, the low superheat absorption only accounts for 5% of the superheater system heat absorption. %. The low pass can be cancelled by appropriately increasing the heating area of ​​the screen and the high pass. However, the boiler type with three flue baffles at the tail to adjust the reheated steam temperature needs to retain the rear flue). The existence of a large degree of low overheating only plays the role of balancing ...

Examples

Embodiment 1

[0022] refer to figure 1 As shown in the figure, the large hollow arrow in the figure is the flow direction of the flue gas, and the small solid arrow is the flow direction of the hot secondary air. A type of secondary reheat boiler with three flues at the tail arranged, including a flue at the end, the flue at the end is divided into three flues in parallel by a cladding wall 15, namely flue 1 at the front of the tail, flue 2 in the middle of the tail, The rear flue 3 at the tail and the front flue 1 at the tail are sequentially provided with the vertical section 13 of the primary low temperature reheater, the horizontal section 10 of the primary low temperature reheater, the economizer (front) 7 and the flue gas adjusting baffle ( Front) 4, the flue 2 in the tail is sequentially provided with the vertical section 14 of the secondary low temperature reheater, the horizontal section 11 of the secondary low temperature reheater, the economizer (middle) 8 and the flue gas regula...

Embodiment 2

[0024] refer to figure 1 As shown, this embodiment is basically the same as Embodiment 1, the difference is: the low-temperature reheater of the front flue 1 at the tail is a secondary low-temperature reheater (the vertical section 13 of the secondary low-temperature reheater in turn along the flue gas direction) , the horizontal section 10 of the secondary low temperature reheater, the low temperature reheater of the flue 2 in the tail is the primary low temperature reheater (the vertical section 14 of the primary low temperature reheater and the horizontal section of the primary low temperature reheater along the flue gas direction are in turn paragraph 11).

Embodiment 3

[0026] Taking the 630°C secondary reheat parameter project as an example, 30% of the flue gas in the BMCR condition passes through the rear flue (3), and this part of the flue gas heats the hot secondary air at the outlet of the air preheater. The temperature of this part of the flue gas is reduced from 735°C to 420°C, and the hot secondary air is heated from 360°C to 478°C.

[0027]

[0028]

[0029] It can be seen from the above table that, compared with the existing triple-flue secondary reheat boiler at the tail, the economizer outlet of the present invention improves the enthalpy at the exit and the boiler efficiency, which is beneficial to the safe and efficient operation of the boiler.

technical field

[0001] The invention belongs to the field of power station boilers. Background technique

[0002] In the existing secondary reheat boiler with three flues at the rear, three heating surfaces of primary low reheat, secondary low reheat and low temperature superheater are usually arranged in the three flues at the rear. However, with the improvement of boiler steam parameters, the low superheat absorption accounts for a small proportion of the superheater system heat absorption (taking the 630℃ secondary reheat parameter project as an example, the low superheat absorption only accounts for 5% of the superheater system heat absorption. %. The low pass can be cancelled by appropriately increasing the heating area of ​​the screen and the high pass. However, the boiler type with three flue baffles at the tail to adjust the reheated steam temperature needs to retain the rear flue). The existence of a large degree of low overheating only plays the role of balancing ...

Examples

Embodiment 1

[0022] refer to figure 1 As shown in the figure, the large hollow arrow in the figure is the flow direction of the flue gas, and the small solid arrow is the flow direction of the hot secondary air. A type of secondary reheat boiler with three flues at the tail arranged, including a flue at the end, the flue at the end is divided into three flues in parallel by a cladding wall 15, namely flue 1 at the front of the tail, flue 2 in the middle of the tail, The rear flue 3 at the tail and the front flue 1 at the tail are sequentially provided with the vertical section 13 of the primary low temperature reheater, the horizontal section 10 of the primary low temperature reheater, the economizer (front) 7 and the flue gas adjusting baffle ( Front) 4, the flue 2 in the tail is sequentially provided with the vertical section 14 of the secondary low temperature reheater, the horizontal section 11 of the secondary low temperature reheater, the economizer (middle) 8 and the flue gas regula...

Embodiment 2

[0024] refer to figure 1 As shown, this embodiment is basically the same as Embodiment 1, the difference is: the low-temperature reheater of the front flue 1 at the tail is a secondary low-temperature reheater (the vertical section 13 of the secondary low-temperature reheater in turn along the flue gas direction) , the horizontal section 10 of the secondary low temperature reheater, the low temperature reheater of the flue 2 in the tail is the primary low temperature reheater (the vertical section 14 of the primary low temperature reheater and the horizontal section of the primary low temperature reheater along the flue gas direction are in turn paragraph 11).

Embodiment 3

[0026] Taking the 630°C secondary reheat parameter project as an example, 30% of the flue gas in the BMCR condition passes through the rear flue (3), and this part of the flue gas heats the hot secondary air at the outlet of the air preheater. The temperature of this part of the flue gas is reduced from 735°C to 420°C, and the hot secondary air is heated from 360°C to 478°C.

[0027]

[0028]

[0029] It can be seen from the above table that, compared with the existing triple-flue secondary reheat boiler at the tail, the economizer outlet of the present invention improves the enthalpy at the exit and the boiler efficiency, which is beneficial to the safe and efficient operation of the boiler.

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