Circulating fluidized bed boiler system for realizing deep peak regulation by regulating circulating ash

Abstract

The utility model discloses a circulating fluidized bed boiler system capable of realizing deep peak regulation by regulating circulating ash. The circulating fluidized bed boiler system comprises a hearth, a separator, a return feeder, an ash cooler and a tail flue, one side of the top of the hearth is provided with an outlet, the outlet is connected with a separator, the upper part of the separator is connected with a tail flue, the bottom of the separator is connected with a return feeder, the return feeder is provided with a return feeder ash discharge port, and the return feeder ash discharge port is respectively communicated with the lower part of the hearth and an ash cooler; an outlet in one side of the ash cooler is connected with the slag warehouse. According to the system, the differential pressure transmitter is used for displaying the size of the differential pressure of the hearth to feed back the circulating ash amount, and the opening degree of the ash cooler is regulated and controlled to control the circulating ash amount entering the boiler, so that the influence of inertia of materials in a circulating loop on load change is reduced, the lowest stable combustion load of the boiler is reduced, and the peak regulation capacity of the boiler is greatly improved.

Description

Technical Field

[0001] The utility model relates to the technical field of circulating fluidized bed boilers, and particularly relates to a circulating fluidized bed boiler system for deep peak shaving by regulating circulating ash. Background Art

[0002] In order to achieve the dual-carbon goal, the country vigorously develops new energy, and the proportion of new energy units represented by wind power and photovoltaic power generation is getting higher and higher. Due to the characteristics of intermittency, volatility, unpredictability, and difficulty in regulation of new energy units, the power grid faces great challenges in how to absorb new energy and ensure safety and stability. Also, due to China's energy composition and the characteristics of existing units, coal-fired units play an increasingly important role in ensuring the absorption capacity of new energy power generation. Therefore, it is necessary to carry out flexibility transformation on coal-fired units to adapt to the power grid load command, especially the ultra-low load operation requirements.

[0003] Circulating fluidized bed (CFB) technology is a clean combustion technology, which is widely used due to its high combustion efficiency, wide fuel applicability, low pollutant emissions, and wide load regulation range. The status of CFB boiler units in ensuring the development of new energy and achieving the dual-carbon goal is becoming more and more important. In order to meet the increasingly stringent environmental protection requirements, the third-generation CFB technology mainly uses high-efficiency separators. The application of this technology increases the influence of the inertia of materials on load changes. How to improve the load change rate is an urgent problem to be solved for CFB boilers. Summary of the Utility Model

[0004] Aiming at the above-mentioned technical deficiencies, the purpose of the utility model is to provide a circulating fluidized bed boiler system for deep peak shaving by regulating circulating ash. This system uses a differential pressure transmitter to display the magnitude of the furnace differential pressure to feedback the circulating ash amount, and controls the opening degree of the cold ash machine to control the amount of circulating ash entering the furnace, thereby reducing the influence of the inertia of materials in the circulating loop on load changes, lowering the minimum stable combustion load of the boiler, and greatly improving the peak shaving ability of the boiler.

[0005] To solve the above technical problems, the utility model adopts the following technical solutions:

[0006] A circulating fluidized bed boiler system for deep peak shaving by regulating circulating ash, comprising a furnace, a separator, a return feeder, a cold ash machine, and a tail flue; one side of the top of the furnace is provided with an outlet, the outlet is connected to a separator, the upper part of the separator is connected to the tail flue, the bottom of the separator is connected to a return feeder, the return feeder is provided with a return feeder ash discharge port, and the return feeder ash discharge port is respectively communicated with the lower part of the furnace and the cold ash machine; the outlet on one side of the cold ash machine is connected to a slag bin.

[0007] Further, it also includes a thermometer, and the thermometer is installed in the lower part of the furnace.

[0008] Further, it also includes a differential pressure transmitter, which is installed in the upper-middle part of the furnace.

[0009] Further, it also includes an ash conveying device, and the outlet of the cold ash machine is connected to the slag bunker through the ash conveying device.

[0010] Further, the ash conveying device includes a slag conveyor and a bucket elevator, and the slag conveyor and the bucket elevator are sequentially installed between the cold ash machine and the slag bunker.

[0011] Further, it also includes a fuel conveying device, which is connected to the bottom of the furnace.

[0012] Further, the fuel conveying device includes a coal bunker, a coal feeder, and a coal dropping pipe. The lower part of the coal bunker is connected to the coal feeder, the outlet of the coal feeder is connected to the coal dropping pipe, and the other end of the coal dropping pipe is connected to the bottom of the furnace.

[0013] Further, it also includes a riser pipe, and the lower part of the separator is connected to the return feeder through the riser pipe.

[0014] Further, it also includes a return feeder ash discharge pipeline, and the ash discharge port of the return feeder is connected to the cold ash machine through the return feeder ash discharge pipeline.

[0015] The beneficial effects of the present utility model are as follows:

[0016] In this system, a cold ash machine is connected at the bottom, and the amount of circulating ash is fed back by the differential pressure transmitter showing the differential pressure of the furnace. By regulating the opening of the cold ash machine, the control of the circulating ash amount entering the furnace is realized. By regulating the circulating ash amount, the influence of the inertia of the materials in the circulating loop on the load change can be reduced, so that the minimum stable combustion load of the boiler is reduced from the traditional 30% to below 15%, greatly improving the peak shaving capacity of the boiler and also meeting the requirements of the energy structure. Description of the Drawings

[0017] In order to more clearly illustrate the technical solutions in the embodiments of the present utility model or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the following drawings are only some embodiments of the present utility model. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0018] Figure 1 It is a schematic structural diagram of a circulating fluidized bed boiler system for realizing deep peak shaving by regulating circulating ash provided for Embodiment 1;

[0019] Explanation of the reference numerals in the drawings:

[0020] 1. Furnace; 2. Coal bunker; 3. Coal feeder; 4. Coal dropping pipe; 5. Separator; 6. Standpipe; 7. Return feeder; 8. Return ash discharge pipe; 9. Ash cooler; 10. Slag conveyor; 11. Bucket elevator; 12. Slag bin; 13. Thermometer; 14. Differential pressure transmitter; 15. Tail flue. Detailed implementation manners

[0021] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0022] As Figure 1 shown, a deep peak shaving circulating fluidized bed boiler system that realizes regulation through circulating ash includes a furnace 1, a coal bunker 2, a coal feeder 3, a coal dropping pipe 4, a separator 5, a standpipe 6, a return feeder 7, a return ash discharge pipe 8, an ash cooler 9, a slag conveyor 10, a bucket elevator 11, a slag bin 12, a thermometer 13, a differential pressure transmitter 14, and a tail flue 15. As shown in the figure, the lower part of the coal bunker 2 is connected with a coal feeder 3, the outlet of the coal feeder 3 is connected with a coal dropping pipe 4, the other end of the coal dropping pipe 4 is connected to the bottom of the furnace 1, one side of the top of the furnace 1 is provided with an outlet, the outlet of the furnace 1 is connected to a separator 5, the upper part of the separator 5 is connected to the tail flue 15, a standpipe 6 and a return feeder 7 are successively installed at the lower part of the separator 5, the bottom of the return feeder 7 is provided with a return feeder ash discharge port, the return feeder ash discharge port is respectively communicated with the lower part of the furnace 1 and the ash cooler 9, the return feeder ash discharge port sends the circulating ash to the ash cooler 9 through a return ash discharge pipeline, and then discharges it to the slag conveyor 10 from the slag discharge port of the ash cooler, and sends it to the slag bin through the slag conveyor 10 and the bucket elevator 11.

[0023] A thermometer 13 is installed at the lower part of the furnace 1, and a differential pressure transmitter 14 is installed at the middle and upper parts. The number of the thermometer 13 and the differential pressure transmitter 14 can be arranged according to the size of the furnace.

[0024] The working principle of the present invention is as follows:

[0025] Before the boiler runs, an inert bed material with a certain height is installed on the air distribution plate. During operation, the fuel falls from the coal bunker 2 onto the coal feeder 3 and then is sent into the furnace 1 through the coal dropping pipe 4. After the fuel is mixed with the bed material and air, it burns in the furnace 1 and is then sent into the separator 5. After the flue gas and material mixture are subjected to gas-solid separation in the separator, the flue gas is sent from the outlet of the separator 5 into the tail flue 15. The separated ash is called circulating ash. The circulating ash is sent from the lower part of the separator 5 into the return feeder 7. A part of the circulating ash is sent into the furnace 1 by the return feeder 7, and the excess circulating ash is sent into the ash cooler 9 through the return feeder ash discharge port and stored in the slag bin 12 through the ash conveying device.

[0026] For different fuels and different boiler loads, there is an optimal amount of circulating ash in the furnace. The amount of circulating ash is fed back by the differential pressure transmitter indicating the differential pressure of furnace 1. At high loads, the opening of the cold ash conveyor 9 can be reduced or it can be in a fully closed state to reduce the amount of ash discharged into the cold ash conveyor 9 and increase the amount of ash returned to furnace 1. At low loads, the opening of the cold ash conveyor 9 can be increased to increase the amount of ash discharged into the cold ash conveyor 9 and reduce the amount of ash returned to furnace 1. The opening of the cold ash conveyor 9 can be adjusted according to the temperature at the lower part of furnace 1 and the differential pressure of furnace 1 at the middle and upper parts. By controlling the circulating ash amount, the influence of the inertia of the materials in the circulating loop on the load change is reduced, so that the boiler load can be further reduced to meet the peak shaving capacity of the power grid.

[0027] Obviously, those skilled in the art can make various changes and modifications to the present utility model without departing from the spirit and scope of the present utility model. Thus, if these modifications and variations of the present utility model fall within the scope of the claims of the present utility model and its equivalent technologies, the present utility model is also intended to include these changes and modifications.

Claims

1. A circulating fluidized bed boiler system that achieves deep peak regulation by regulating circulating ash, characterized in that: Including furnace, separator, return feeder, ash cooler, and tail flue; An outlet is provided on one side of the furnace top, which is connected to a separator. The upper part of the separator is connected to the tail flue, and the bottom of the separator is connected to a returner. The returner is provided with an ash discharge port, which are respectively connected to the lower part of the furnace and the ash cooler; an outlet on one side of the ash cooler is connected to the slag storage.

2. A circulating fluidized bed boiler system for achieving deep peak regulation by regulating circulating ash according to claim 1, characterized in that: Also included is a thermometer, which is installed at the lower part of the furnace.

3. The circulating fluidized bed boiler system for achieving deep peak regulation by regulating circulating ash according to claim 1, characterized in that: It also includes a differential pressure transmitter, which is installed in the upper middle part of the furnace.

4. The circulating fluidized bed boiler system for achieving deep peak regulation by regulating circulating ash according to claim 1, characterized in that: It also includes an ash conveying device, and the outlet of the ash cooler is connected to the slag bin through the ash conveying device.

5. A circulating fluidized bed boiler system for achieving deep peak regulation by regulating circulating ash according to claim 4, characterized in that: The ash conveying device comprises a slag conveyor and a bucket elevator, and the slag conveyor and the bucket elevator are sequentially installed between the ash cooler and the slag storage.

6. The circulating fluidized bed boiler system for achieving deep peak regulation by regulating circulating ash according to claim 1, characterized in that: It also includes a fuel delivery device, which is connected to the bottom of the furnace.

7. A circulating fluidized bed boiler system for achieving deep peak regulation by regulating circulating ash according to claim 6, characterized in that: The fuel conveying device comprises a coal bunker, a coal feeder and a coal dropping pipe. The lower part of the coal bunker is connected to the coal feeder, the outlet of the coal feeder is connected to the coal dropping pipe, and the other end of the coal dropping pipe is connected to the bottom of the furnace.

8. The circulating fluidized bed boiler system for achieving deep peak regulation by regulating circulating ash according to claim 1, characterized in that: It also includes a vertical pipe, and the lower part of the separator is connected with the return device through the vertical pipe.

9. The circulating fluidized bed boiler system for achieving deep peak regulation by regulating circulating ash according to claim 1, characterized in that: It also includes a return material ash discharge pipeline, and the ash discharge port of the return material device is connected to the ash cooler through the return material ash discharge pipeline.

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