Flexible peak regulation and energy supply device for circulating fluidized bed boiler

Abstract

The utility model belongs to the technical field of circulating fluidized bed boilers, and particularly relates to a flexible peak regulation and energy supply device of a circulating fluidized bed boiler. The device comprises a hearth, a cyclone separator and a tail flue, wherein the cyclone separator is connected with a material returning device; the interior of the fluidized bed bin is divided into a peak shaving bin and an energy supply bin through a partition wall, the peak shaving bin and the energy supply bin are communicated from the upper side of the partition wall, a heat exchange unit is installed in the energy supply bin, a peak shaving air chamber is arranged at the bottom of the peak shaving bin, an energy supply air chamber is arranged at the bottom of the energy supply bin, and the material returning device is connected with the peak shaving bin through an ash channel; the peak regulation bin is connected with the hearth through an ash channel; the boiler further comprises an ash conveying fan and a fluidization fan, the ash conveying fan is connected with the hearth and the energy supply bin through pipelines, and the fluidization fan is connected with the peak regulation air chamber and the energy supply air chamber through pipelines. According to the flexible peak regulation and energy supply device for the circulating fluidized bed boiler, the rapid load changing speed of the circulating fluidized bed boiler is increased, and high-grade heat and steam are provided according to external requirements.

Description

TECHNICAL FIELD

[0001] The utility model belongs to the technical field of circulating fluidized bed boiler, and particularly relates to a circulating fluidized bed boiler flexible peak shaving and energy supply device. BACKGROUND

[0002] The energy endowment characteristics of "rich coal, poor oil and little gas" in China are obvious, which determines the important position of coal in energy consumption. In the process of establishing a new power system dominated by new energy, the role of coal power as "ballast" is more prominent, but higher requirements are put forward for the flexibility of coal power units. The circulating fluidized bed boiler is an important part of the thermal power generating unit, and how to respond to the requirements of the development of the new power system has become a problem for the development of the industry.

[0003] Patent CN207279614U proposes a circulating fluidized bed boiler load adjusting device, which adjusts the circulating ash concentration in the furnace by discharging and inputting the circulating ash in the circulating fluidized bed boiler, controls the convection heat transfer in the furnace, and can realize rapid load change. But the circulating ash directly cools into the ash storage bin, which wastes the high-grade energy in the high-temperature circulating ash.

[0004] Patent CN205402701U proposes a device for rapidly adjusting the load of a circulating fluidized bed, which connects the bottom of the return feeder with the lower part of the tail flue through the return feeder ash discharge pipe to realize the effect of rapidly adjusting the load of the circulating fluidized bed boiler. But the water-cooled jacket cooling capacity of the ash discharge pipe is limited in actual operation, and the high-temperature ash of the return feeder cannot be cooled to the smoke temperature level of the tail flue, which on the one hand may cause the rapid rise of the exhaust gas temperature and the ash temperature of the flue hopper, causing the failure of the downstream equipment, and on the other hand may also cause poor ventilation of the flue, affecting the safe and stable operation of the boiler. UTILITY MODEL CONTENTS

[0005] In order to solve the above problems existing in the prior art, the purpose of the utility model is to provide a circulating fluidized bed boiler flexible peak shaving and energy supply device, which improves the rapid load change rate of the circulating fluidized bed boiler, provides high-grade heat and steam according to external demand, and better meets the demand of the new power system for coal power units.

[0006] The technical scheme adopted by the utility model is:

[0007] A circulating fluidized bed boiler flexible peak shaving and energy supply device, comprising a furnace, a cyclone separator connected to the upper part of the furnace through a flue, a tail flue connected to the top of the cyclone separator, and a return feeder connected to the bottom of the cyclone separator through an ash channel.

[0008] The utility model also comprises a fluidized bed bin, a partition wall is arranged in the fluidized bed bin, the two sides of the partition wall are a peak regulation bin and an energy supply bin respectively, the peak regulation bin and the energy supply bin are communicated from the upside of the partition wall, a heat exchange unit is installed in the energy supply bin, a peak regulation air chamber is arranged at the bottom of the peak regulation bin, an energy supply air chamber is arranged at the bottom of the energy supply bin, a material return device is connected with the peak regulation bin through an ash channel, and the peak regulation bin is connected with a furnace through a pipeline;

[0009] The utility model also comprises an ash conveying fan and a fluidization fan, the ash conveying fan is connected with the furnace and the energy supply bin through a pipeline respectively, and the fluidization fan is connected with the peak regulation air chamber and the energy supply air chamber through a pipeline respectively.

[0010] The utility model discloses a CFB boiler that can adapt to flexible peak regulation, which meets the requirements of low load operation and rapid load increase of the CFB boiler. When the CFB boiler reduces load, the ash amount of the main circulating loop is flexibly adjusted, the furnace temperature is improved, which is beneficial to fuel burnout and SNCR denitration investment, and the boiler efficiency is improved and the pollutant emission is reduced under low load peak regulation. When the CFB boiler increases load, the ash concentration in the furnace is improved, heat exchange is enhanced, and the rapid load change rate of the boiler is improved. According to external requirements, high-temperature circulating ash in the fluidized bed bin is used to heat external medium, steam or hot water with different parameters can be provided, and energy can be supplied externally. A preheater is arranged at the outlet of the fluidization fan to heat fluidization air, energy loss caused by cold air fluidization in the fluidized bed bin is reduced, and the energy utilization rate of circulating ash is improved.

[0011] As a preferred scheme of the utility model, the material return device is connected with the peak regulation bin through a material return device to fluidized bed bin ash channel, and an ash control valve is arranged on the material return device to fluidized bed bin ash channel.

[0012] As a preferred scheme of the utility model, the heat exchange unit comprises a heated surface arranged in the energy supply bin, one end of the heated surface is connected with an external working medium inlet pipeline, and one end of the heated surface is connected with an external working medium outlet pipeline.

[0013] As a preferred scheme of the utility model, the ash conveying fan is connected with the energy supply bin through an energy supply bin outlet ash channel, and an energy supply bin outlet ash channel shut-off valve is arranged on the energy supply bin outlet ash channel.

[0014] As a preferred scheme of the utility model, the outlet of the fluidization fan is connected with a fluidization air main pipe, and the other end of the fluidization air main pipe is connected with the peak regulation air chamber and the energy supply air chamber through a pipeline respectively.

[0015] As a preferred scheme of the utility model, the fluidization air main pipe is connected with the peak regulation air chamber through a peak regulation air pipe, and a peak regulation shut-off valve is arranged on the peak regulation air pipe.

[0016] As a preferred scheme of the utility model, the fluidization air main pipe is connected with the energy supply air chamber through an energy supply air pipe, and an energy supply shut-off valve is arranged on the energy supply air pipe.

[0017] As a preferred scheme of the utility model, the fluidization wind main pipe passes through the preheater of the tail flue.

[0018] As a preferred scheme of the utility model, the peak regulation bin is connected with the furnace through the fluidized bed bin to furnace ash channel, and the fluidized bed bin to furnace ash control valve is arranged on the fluidized bed bin to furnace ash channel.

[0019] As a preferred scheme of the utility model, the top of the fluidized bed bin is provided with fluidization wind outlet air channel.

[0020] The utility model has the advantages of:

[0021] The utility model can adapt to the requirement of flexible peak regulation to the low load operation and rapid load increase of CFB boiler. When the CFB boiler reduces load, the ash amount of the main circulating loop is flexibly adjusted, the furnace temperature is improved, fuel burnout and SNCR denitration investment are beneficial, the boiler efficiency is improved and pollutant emission is reduced under low load peak regulation. When the CFB boiler increases load, the furnace ash concentration is improved, heat exchange is enhanced, and the rapid load change rate of the boiler is improved. According to external demand, the high-temperature circulating ash in the fluidized bed bin is used to heat external medium, steam or hot water with different parameters can be provided, and energy is supplied externally. The fluidization fan outlet is provided with a preheater to heat the fluidization wind, energy loss caused by cold air fluidization in the fluidized bed bin is reduced, and the circulating ash energy utilization rate is improved. BRIEF DESCRIPTION OF DRAWINGS

[0022] Figure 1 It is the structure schematic diagram of the utility model;

[0023] Figure 2 It is the partial structure drawing of the utility model.

[0024] In the drawing: 1 - furnace; 2 - cyclone separator; 3 - return material device; 4 - tail flue; 5 - ash control valve; 6 - return material device to fluidized bed bin ash channel; 7 - fluidized bed bin; 8 - peak regulation bin; 9 - partition wall; 10 - peak regulation air chamber; 11 - external working medium inlet pipeline; 12 - heating surface; 13 - external working medium outlet pipeline; 14 - energy supply bin; 15 - energy supply air chamber; 16 - energy supply bin outlet ash channel shut-off valve; 17 - energy supply bin outlet ash channel; 18 - ash conveying fan; 19 - ash conveying pipeline; 20 - fluidization fan; 21 - fluidization wind main pipe; 22 - peak regulation air pipe; 23 - peak regulation stop valve; 24 - energy supply air pipe; 25 - energy supply stop valve; 26 - fluidized bed bin to furnace ash control valve; 27 - fluidized bed bin to furnace ash channel; 28 - fluidization wind outlet air channel; 29 - preheater. DETAILED DESCRIPTION

[0025] In order to make the purpose, technical scheme and advantages of the embodiments of the utility model clearer, the technical scheme in the embodiments of the utility model will be described clearly and completely in combination with the drawings in the embodiments of the utility model below. Obviously, the described embodiments are part of the embodiments of the utility model, rather than all the embodiments. The components of the embodiments of the utility model described and shown in the drawings can be arranged and designed in various different configurations.

[0026] Therefore, the following detailed description of the embodiments of the utility model provided in the drawings is not intended to limit the scope of the claimed utility model, but only represents selected embodiments of the utility model. Based on the embodiments in the utility model, all other embodiments obtained by those of ordinary skill in the art without creative labor fall within the scope of protection of the utility model. It should be noted that the embodiments in the utility model and the features in the embodiments can be combined with each other without conflict.

[0027] As shown in Figure 1 and Figure 2 The circulating fluidized bed boiler flexible peak shaving and energy supply device of the embodiment comprises a hearth 1, a cyclone separator 2 connected to the upper part of the hearth 1 through a flue, a tail flue 4 connected to the top of the cyclone separator 2, and a back feeder 3 connected to the bottom of the cyclone separator 2 through an ash channel.

[0028] It also comprises a fluidized bed bin 7, wherein a partition wall 9 is arranged in the fluidized bed bin 7, and a peak shaving bin 8 and an energy supply bin 14 are arranged on the two sides of the partition wall 9, respectively. The peak shaving bin 8 and the energy supply bin 14 are communicated from the upper side of the partition wall 9. A heat exchange unit is installed in the energy supply bin 14. A peak shaving air chamber 10 is arranged at the bottom of the peak shaving bin 8, and an energy supply air chamber 15 is arranged at the bottom of the energy supply bin 14. The back feeder 3 is connected to the peak shaving bin 8 through a pipeline, and the peak shaving bin 8 is connected to the hearth 1 through a pipeline.

[0029] It also comprises an ash conveying fan 18 and a fluidizing fan 20. The ash conveying fan 18 is connected to the hearth 1 and the energy supply bin 14 through pipelines, respectively. The fluidizing fan 20 is connected to the peak shaving air chamber 10 and the energy supply air chamber 15 through pipelines, respectively.

[0030] Specifically, the back feeder 3 is connected to the fluidized bed bin 7 through a back feeder to fluidized bed bin ash channel 6, and an ash control valve 5 is arranged on the back feeder to fluidized bed bin ash channel 6.

[0031] The heat exchange unit comprises a heated surface 12 arranged in the energy supply bin 14. One end of the heated surface 12 is connected to an external working medium inlet pipeline 11, and the other end of the heated surface 12 is connected to an external working medium outlet pipeline 13.

[0032] The ash conveying fan 18 is connected to the energy supply bin 14 through an energy supply bin outlet ash channel 17, and an energy supply bin outlet ash channel shut-off valve 16 is arranged on the energy supply bin outlet ash channel 17.

[0033] The outlet of the fluidizing fan 20 is connected with a fluidizing air main pipe 21, the other end of the fluidizing air main pipe 21 is connected with the peak shaving air chamber 10 and the energy supply air chamber 15 through pipes respectively. The fluidizing air main pipe 21 passes through the preheater 29 of the tail flue 4. The fluidizing air main pipe 21 is connected with the peak shaving air chamber 10 through a peak shaving air pipe 22, and the peak shaving air pipe 22 is provided with a peak shaving stop valve 23. The fluidizing air main pipe 21 is connected with the energy supply air chamber 15 through an energy supply air pipe 24, and the energy supply air pipe 24 is provided with an energy supply stop valve 25.

[0034] The peak shaving bin 8 is connected with the furnace 1 through a fluidized bed bin to furnace ash channel 27, and the fluidized bed bin to furnace ash channel 27 is provided with a fluidized bed bin to furnace ash control valve 26.

[0035] The top of the fluidized bed bin 7 is provided with a fluidizing air outlet air channel 28.

[0036] The conventional circulating fluidized bed boiler main circulating loop comprises the furnace 1, the cyclone 2 and the return feeder 3. The flue gas at the outlet of the furnace 1 is separated and dedusted through the cyclone 2, the separated ash returns to the furnace 1 through the return feeder 3, and the flue gas after being dedusted through the cyclone 2 leaves the boiler after heat exchange through the tail flue 4.

[0037] The utility model discloses a functional expansion on the basis of the conventional circulating fluidized bed boiler, and a fluidized bed bin 7 is arranged below the return feeder 3 of the main circulating loop, the return feeder to fluidized bed bin ash channel 6 is connected with the boiler return feeder 33, and the return feeder to fluidized bed bin ash channel 6 is provided with an ash control valve 5. The fluidized bed bin 7 is divided into a peak shaving bin 8 and an energy supply bin 14 and is separated by a partition wall 9. The peak shaving bin 8 is empty and does not arrange the heating surface 12 therein, the energy supply bin 14 is provided with the heating surface 12, and the heating surface 12 is connected with the external working medium inlet pipeline 11 and the external working medium outlet pipeline 13. The peak shaving bin 8 and the energy supply bin 14 are respectively provided with the peak shaving air chamber 10 and the energy supply air chamber 15 below. The peak shaving bin 8 is connected with the furnace 1 through the fluidized bed bin to furnace ash channel 27, and the fluidized bed bin to furnace ash channel 27 is provided with the fluidized bed bin to furnace ash control valve 26. The energy supply bin outlet ash channel 17 is provided with the energy supply bin outlet ash channel shut-off valve 16, the heat-exchanged ash is collected on the ash conveying pipeline 19 after the ash conveying fan 18, and is pneumatically conveyed into the furnace 1. The outlet fluidizing air of the fluidizing fan 20 is heated first through the preheater 29 in the boiler tail flue 4, is improved in temperature, and is then conveyed through the fluidizing air main pipe 21, is connected with the peak shaving air chamber 10 and the energy supply air chamber 15 through the peak shaving air pipe 22, the peak shaving stop valve 23, the energy supply air pipe 24 and the energy supply stop valve 25 respectively. The fluidizing air in the peak shaving bin 8 and the energy supply bin 14 can be led out through the fluidizing air outlet air channel 28.

[0038] This invention adapts to the requirements of flexible peak shaving for low-load operation and rapid load increase of CFB boilers. When the CFB boiler reduces its load, the ash content in the main circulation loop is flexibly adjusted to increase the furnace temperature, which facilitates fuel combustion and SNCR denitrification, thereby improving boiler efficiency and reducing pollutant emissions under low-load peak shaving. When the CFB boiler increases its load, the ash concentration in furnace 1 is increased to enhance heat exchange, thereby increasing the boiler's rapid load change rate. Based on external demand, the high-temperature circulating ash in the fluidized bed chamber 7 can be used to heat external media, providing steam or hot water with different parameters for external energy supply. A preheater 29 is installed at the outlet of the fluidizing blower 20 to heat the fluidizing air, reducing energy loss caused by cold air fluidization in the fluidized bed chamber 7 and improving the energy utilization rate of the circulating ash.

[0039] Example:

[0040] Increasing bed temperature: As the boiler load decreases, the bed temperature in furnace 1 also decreases. Incomplete fuel combustion within furnace 1 and the temperature falling outside the effective SNCR denitrification temperature range lead to reduced boiler efficiency and increased NO at the boiler outlet. X Increased emission concentration. To address the above issues, the ash control valve 5 is opened, allowing some of the circulating ash from the return feeder 3 to be returned to the fluidized bed ash channel 6 and stored in the peak shaving silo 8. This gradually reduces the ash concentration in the furnace 1, increases the bed temperature, and thus improves combustion efficiency and ensures the effective operation of the SNCR.

[0041] Rapid Load Increase: When the boiler needs to respond quickly to external loads, ash is discharged from the return feeder 3 to the peak shaving silo 8. The circulating ash in the peak shaving silo 8, under the action of fluidizing air, is sent into the furnace 1 through the fluidized bed silo to the furnace ash channel 27. The ash flow rate entering the furnace 1 is controlled by the fluidized bed silo to the furnace ash control valve 26 and the fluidizing air volume to regulate the load change rate. As the amount of ash entering the furnace increases, the ash concentration and heat transfer coefficient in the furnace 1 increase rapidly, achieving the purpose of rapid load increase. The fluidizing air is provided by the fluidizing blower 20. After the high-temperature flue gas in the preheater 29 exchanges heat with the flue gas at the tail end of the boiler and is heated, it is then sent into the peak shaving air chamber 10 through the fluidizing air main duct 21, the peak shaving air duct 22, and the peak shaving shut-off valve 23. The peak shaving air chamber 10 is equipped with an air cap to uniformly and stably deliver the fluidizing air into the peak shaving silo 8.

[0042] External energy supply: when there is external energy supply demand, usually part of the steam is extracted from the steam turbine side to reduce pressure and temperature, and the external energy supply is directly or indirectly supplied, which wastes high-grade steam and is not economical. When there is external energy supply demand, the system sends a large amount of circulating ash in the main circulating loop of the boiler to the peak regulation bin 8 through the material return device to the fluidized bed bin ash channel 6, at this time the fluidized bed bin to the furnace ash control valve 26 is in the closed state, after being fluidized by the fluidizing air in the peak regulation bin 8, it is turned into the energy supply bin 14, the energy supply bin 14 is provided with a heating surface 12, according to the external demand, hot water / steam with different parameters is provided, the external working medium is introduced and introduced through the external working medium inlet pipeline 11 and the external working medium outlet pipeline 13, and the circulating ash after heat exchange is collected in the ash conveying pipeline 19 and then returned to the furnace 1 by the ash conveying fan 18. The fluidizing air in each air chamber is provided by the fluidizing air fan 20, after being heated by the high-temperature flue gas in the preheater 29 and the boiler tail flue 4, the fluidizing air is sent into the peak regulation air chamber 10 and the energy supply air chamber 15 through the fluidizing air main pipe 21, the peak regulation air pipe 22, the peak regulation stop valve 23 and the energy supply air pipe 24, the energy supply stop valve 25, and the air cap provided on the peak regulation air chamber 10 and the energy supply air chamber 15 can uniformly and stably send the fluidizing air into the peak regulation bin 8 and the energy supply bin 14. The fluidizing air after fluidization can be introduced through the fluidizing air outlet air channel 28.

[0043] The utility model is not limited to the above optional implementation, anyone can draw other various forms of products under the enlightenment of the utility model, but no matter make any change in its shape or structure, if the technical scheme falls into the utility model claim definition range, it falls in the protection scope of the utility model.

Claims

1. A circulating fluidized bed boiler flexible peak shaving and power supply device, characterized in that: It comprises a furnace (1), the upper part of the furnace (1) is connected with a cyclone (2) through a flue, the top of the cyclone (2) is connected with a tail flue (4), the bottom of the cyclone (2) is connected with a return material device (3) through an ash channel; It also comprises a fluidized bed bin (7), a partition wall (9) is arranged in the fluidized bed bin (7), the two sides of the partition wall (9) are a peak regulation bin (8) and an energy supply bin (14) respectively, the peak regulation bin (8) and the energy supply bin (14) are communicated from the upper side of the partition wall (9), a heat exchange unit is installed in the energy supply bin (14), a peak regulation air chamber (10) is arranged at the bottom of the peak regulation bin (8), an energy supply air chamber (15) is arranged at the bottom of the energy supply bin (14), the return material device (3) is connected with the peak regulation bin (8) through a pipeline, and the peak regulation bin (8) is connected with the furnace (1) through a pipeline. It also comprises an ash conveying fan (18) and a fluidization fan (20), the ash conveying fan (18) is connected with the furnace (1) and the energy supply bin (14) through pipelines respectively, and the fluidization fan (20) is connected with the peak regulation air chamber (10) and the energy supply air chamber (15) through pipelines respectively.

2. The device for flexible peak shaving and energy supply of a circulating fluidized bed boiler according to claim 1, characterized in that: The return material device (3) is connected with the peak regulation bin (8) through a return material device to fluidized bed bin ash channel (6), and an ash control valve (5) is arranged on the return material device to fluidized bed bin ash channel (6).

3. The device for flexible peak shaving and energy supply of a circulating fluidized bed boiler according to claim 1, characterized in that: The heat exchange unit comprises a heated surface (12) arranged in the energy supply bin (14), one end of the heated surface (12) is connected with an external working medium inlet pipeline (11), and one end of the heated surface (12) is connected with an external working medium outlet pipeline (13).

4. The device for flexible peak shaving and energy supply of a circulating fluidized bed boiler according to claim 1, characterized in that: The ash conveying fan (18) is connected with the energy supply bin (14) through an energy supply bin outlet ash channel (17), and an energy supply bin outlet ash channel shut-off valve (16) is arranged on the energy supply bin outlet ash channel (17).

5. The circulating fluidized bed boiler flexible peak shaving and energy supply device according to claim 1, characterized in that: An outlet of the fluidization fan (20) is connected with a fluidization air main pipeline (21), and the other end of the fluidization air main pipeline (21) is connected with the peak regulation air chamber (10) and the energy supply air chamber (15) through pipelines respectively.

6. A circulating fluidized bed boiler flexible peak shaving and energy supply device according to claim 5, characterized in that: The fluidization air main pipeline (21) passes through a preheater (29) of the tail flue (4).

7. The circulating fluidized bed boiler flexible peak shaving and energy supply device according to claim 5, characterized in that: The fluidization air main pipeline (21) is connected with the peak regulation air chamber (10) through a peak regulation air pipeline (22), and a peak regulation cut-off valve (23) is arranged on the peak regulation air pipeline (22).

8. The circulating fluidized bed boiler flexible peak shaving and energy supply device according to claim 5, characterized in that: The fluidization air main pipeline (21) is connected with the energy supply air chamber (15) through an energy supply air pipeline (24), and an energy supply cut-off valve (25) is arranged on the energy supply air pipeline (24).

9. The circulating fluidized bed boiler flexible peak shaving and energy supply device according to claim 1, characterized in that: The peak regulation bin (8) is connected with the furnace (1) through a fluidized bed bin to furnace ash channel (27), and a fluidized bed bin to furnace ash control valve (26) is arranged on the fluidized bed bin to furnace ash channel (27).

10. A flexible peak shaving and energy supply device for a circulating fluidized bed boiler according to any one of claims 1 to 9, characterized in that: A fluidization air outlet air channel (28) is arranged at the top of the fluidized bed bin (7).

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