Heat exchange system for coal-fired boiler

Abstract

The utility model relates to the technical field of heat exchange, in particular to a heat exchange system for a coal-fired boiler, which comprises a steam inlet pipeline communicated with a first steam passing pipeline, a second steam passing pipeline, a third steam passing pipeline and a fourth steam passing pipeline. The outlet ends of the steam passing pipelines are connected with a first heat exchanger, a second heat exchanger, a third heat exchanger and a fourth heat exchanger respectively, the outlet ends of the first heat exchanger and the second heat exchanger are communicated with a first steam outlet pipeline, the outlet ends of the third heat exchanger and the fourth heat exchanger are communicated with a second steam outlet pipeline, and the first steam outlet pipeline and the second steam outlet pipeline are jointly communicated with a water collecting device. The air outlet end of the water collecting device is connected with an exhaust pipeline, and the water outlet end of the water collecting device is connected with a drainage pipeline. The control capability of the steam passing pipeline and the steam outlet pipeline is enhanced, the adjustable capability of the whole heat exchange system is improved, the phenomenon of water vapor extrusion is avoided, and smooth drainage in the heat exchanger is ensured, so that the operation of the whole heat exchange system is ensured.

Description

Technical Field

[0001] The utility model relates to the technical field of heat exchange, and specifically discloses a heat exchange system for a coal-fired boiler. Background Art

[0002] Before the coal-fired boiler starts to operate, grid connection tests and load rejection tests need to be carried out. To ensure the normal progress of the tests, it is necessary to prevent the phenomenon of low-temperature corrosion at the cold end of the air preheater; traditional methods all adopt the method of hot air recirculation or installing a warm air heater to send high-temperature air flow into the coal-fired boiler, so as to ensure that the temperature at the cold end of the air preheater is higher than the acid dew point value, thereby ensuring the reliability and accuracy of the test and test data.

[0003] At present, personnel in this field usually use auxiliary steam as the steam source, so as to increase the temperature of the cold air through the heat exchanger and convert the cold air into hot air; a main valve is usually set on the pipeline connected to the inlet of the heat exchanger. When the temperature at the outlet end of the heat exchanger is too high, the method of shutting down the main valve can be used for adjustment. In the actual application process of the above method, due to the too low temperature in winter and the poor drainage in the heat exchanger, a large amount of accumulated water will be generated. If the main valve is opened again, there will be a pressure difference in the outlet channel of the heat exchanger, resulting in the phenomenon of water vapor extrusion, and further leading to poor drainage of the heat exchanger, thus affecting the operation of the overall heat exchange system. Summary of the Utility Model

[0004] Aiming at the problem that the heat exchange system carried on the coal-fired boiler has poor drainage of the heat exchanger due to the pressure difference in the outlet channel of the heat exchanger, the utility model provides a heat exchange system for a coal-fired boiler.

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

[0006] A heat exchange system for a coal-fired boiler includes a steam inlet pipe, the steam inlet pipe is connected to a first steam passing pipe, a second steam passing pipe, a third steam passing pipe, and a fourth steam passing pipe. Control valve groups are arranged on the pipelines of the first steam passing pipe, the second steam passing pipe, the third steam passing pipe, and the fourth steam passing pipe. The outlet ends of the first steam passing pipe, the second steam passing pipe, the third steam passing pipe, and the fourth steam passing pipe are respectively connected to a first heat exchanger, a second heat exchanger, a third heat exchanger, and a fourth heat exchanger. The outlet ends of the first heat exchanger and the second heat exchanger are jointly connected and communicated with a first steam outlet pipe. The outlet ends of the third heat exchanger and the fourth heat exchanger are jointly connected and communicated with a second steam outlet pipe. The first steam outlet pipe and the second steam outlet pipe are jointly connected to a water collecting device. The air outlet end of the water collecting device is connected to an exhaust pipe, and the water outlet end of the water collecting device is connected to a drain pipe.

[0007] Preferably, each of the control valve groups includes a first stop valve connected to the first steam passing pipeline, the second steam passing pipeline, the third steam passing pipeline, and the fourth steam passing pipeline. An electric control valve is installed at the outlet end of the first stop valve, and a second stop valve is installed at the outlet end of the electric control valve.

[0008] Preferably, the first steam passing pipeline, the second steam passing pipeline, the third steam passing pipeline, and the fourth steam passing pipeline are respectively paralleled with a first direct pipeline, a second direct pipeline, a third direct pipeline, and a fourth direct pipeline. The outlet ends of the first direct pipeline, the second direct pipeline, the third direct pipeline, and the fourth direct pipeline are respectively communicated with a first heat exchanger, a second heat exchanger, a third heat exchanger, and a fourth heat exchanger. Third stop valves are installed on the pipelines of the first direct pipeline, the second direct pipeline, the third direct pipeline, and the fourth direct pipeline.

[0009] Preferably, the first heat exchanger and the second heat exchanger have the same number of tube passes, the third heat exchanger and the fourth heat exchanger have the same number of tube passes, and the number of tube passes of the third heat exchanger is greater than that of the first heat exchanger.

[0010] Preferably, the number of tube passes of the third heat exchanger is at least twice that of the first heat exchanger.

[0011] Preferably, steam traps are installed at the outlet ends of the first heat exchanger, the second heat exchanger, the third heat exchanger, and the fourth heat exchanger.

[0012] Preferably, an air flow valve is installed on the exhaust pipeline, and a guide cylinder is installed at the outlet end of the exhaust pipeline.

[0013] Preferably, a liquid flow valve is installed on the drain pipeline, and the outlet end of the drain pipeline is communicated with a water receiving bucket.

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

[0015] In the present utility model, the first steam passing pipeline, the second steam passing pipeline, the third steam passing pipeline, and the fourth steam passing pipeline can effectively share the inlet steam pressure of high-temperature steam, and perform heat exchange through the first heat exchanger, the second heat exchanger, the third heat exchanger, and the fourth heat exchanger. After the heat exchange is completed, the separated gas can be transported to the water collecting device through the first steam outlet pipeline and the second steam outlet pipeline. The water collecting device can effectively separate the gas and the liquid, so as to ensure that the pressure difference of the outlet channel of the heat exchanger is within a reasonable range; the present utility model can effectively improve the pressure tolerance strength of the overall heat exchange system, enhance the control ability of the steam passing pipeline and the steam outlet pipeline, improve the adjustable ability of the overall heat exchange system, avoid the phenomenon of water vapor exclusion, ensure smooth drainage in the heat exchanger, and thus ensure the operation of the overall heat exchange system. Therefore, it has a very wide application prospect. Description of the Drawings

[0016] To more clearly illustrate the technical solution of the present utility model, the accompanying drawings required in the description will be briefly introduced below. Obviously, the accompanying drawings in the following description are only some embodiments of the present utility model. For those of ordinary skill in the art, without creative efforts, other accompanying drawings can be obtained based on these drawings;

[0017] Figure 1 It is a schematic diagram of the overall system structure of the present utility model;

[0018] In the figure: 1. Steam inlet pipe, 2. First steam passing pipe, 3. Second steam passing pipe, 4. Third steam passing pipe, 5. Fourth steam passing pipe, 6. First heat exchanger, 7. Second heat exchanger, 8. Third heat exchanger, 9. Fourth heat exchanger, 10. First steam outlet pipe, 11. Second steam outlet pipe, 12. Water collection device, 13. Exhaust pipe, 14. Drain pipe, 15. First stop valve, 16. Electric control valve, 17. Second stop valve, 18. First straight pipe, 19. Second straight pipe, 20. Third straight pipe, 21. Fourth straight pipe, 22. Third stop valve, 23. Steam trap, 24. Air flow valve, 25. Flow guide cylinder, 26. Liquid flow valve, 27. Water bucket. Specific embodiments

[0019] To make the objectives, features, and advantages of the present utility model more obvious and understandable, the technical solutions in the present utility model will be clearly and completely described below in conjunction with the accompanying drawings in the specific embodiments of the present utility model. Obviously, the embodiments described below are only some embodiments of the present utility model, rather than all embodiments. Based on the embodiments in this patent, all other embodiments obtained by those of ordinary skill in the art without creative efforts fall within the scope of protection of this patent.

[0020] This specific embodiment provides a heat exchange system for a coal-fired boiler, as Figure 1 shown; it includes a steam inlet pipe 1, and the steam inlet pipe 1 inputs high-temperature steam into this system. The steam inlet pipe 1 is connected to a first steam passing pipe 2, a second steam passing pipe 3, a third steam passing pipe 4, and a fourth steam passing pipe 5. The high-temperature steam passing through the steam inlet pipe 1 can evenly flow into the first steam passing pipe 2, the second steam passing pipe 3, the third steam passing pipe 4, and the fourth steam passing pipe 5, thereby evenly dispersing the high-temperature steam. The outlet ends of the first steam passing pipe 2, the second steam passing pipe 3, the third steam passing pipe 4, and the fourth steam passing pipe 5 are respectively connected to a first heat exchanger 6, a second heat exchanger 7, a third heat exchanger 8, and a fourth heat exchanger 9. The high-temperature steam entering the first heat exchanger 6, the second heat exchanger 7, the third heat exchanger 8, and the fourth heat exchanger 9 can effectively exchange heat.

[0021] Control valve groups are provided on the pipelines of the first steam passing pipeline 2, the second steam passing pipeline 3, the third steam passing pipeline 4, and the fourth steam passing pipeline 5; each control valve group includes a first stop valve 15 connected to the first steam passing pipeline 2, the second steam passing pipeline 3, the third steam passing pipeline 4, and the fourth steam passing pipeline 5. A total of four first stop valves 15 are provided and distributed on each steam passing pipeline, and each first stop valve 15 can control the on-off of the first steam passing pipeline 2, the second steam passing pipeline 3, the third steam passing pipeline 4, and the fourth steam passing pipeline 5. An electric control valve 16 is installed at the outlet end of the first stop valve 15, and a second stop valve 17 is installed at the outlet end of the electric control valve 16; the electric control valve 16 can adjust the steam inlet flow rate of the first steam passing pipeline 2, the second steam passing pipeline 3, the third steam passing pipeline 4, and the fourth steam passing pipeline 5, so as to further control the high-temperature steam inlet rate in the overall system; the second stop valve 17 can provide protection for the electric control valve 16 to ensure that when the electric control valve 16 is damaged, the second stop valve 17 can timely adjust the on-off of each steam passing pipeline, thereby reducing accident losses.

[0022] Among them, a first direct pipeline 18, a second direct pipeline 19, a third direct pipeline 20, and a fourth direct pipeline 21 are respectively connected in parallel with the first steam passing pipeline 2, the second steam passing pipeline 3, the third steam passing pipeline 4, and the fourth steam passing pipeline 5. The outlet ends of the first direct pipeline 18, the second direct pipeline 19, the third direct pipeline 20, and the fourth direct pipeline 21 are respectively connected to the first heat exchanger 6, the second heat exchanger 7, the third heat exchanger 8, and the fourth heat exchanger 9. Third stop valves 22 are installed on the pipelines of the first direct pipeline 18, the second direct pipeline 19, the third direct pipeline 20, and the fourth direct pipeline 21; by setting the first direct pipeline 18, the second direct pipeline 19, the third direct pipeline 20, and the fourth direct pipeline 21, a bypass channel can be provided for the first heat exchanger 6, the second heat exchanger 7, the third heat exchanger 8, and the fourth heat exchanger 9. When the first steam passing pipeline 2, the second steam passing pipeline 3, the third steam passing pipeline 4, and the fourth steam passing pipeline 5 are undergoing regular maintenance, the first direct pipeline 18, the second direct pipeline 19, the third direct pipeline 20, and the fourth direct pipeline 21 can temporarily undertake the structural function of passing high-temperature steam, thereby ensuring the normal operation of the overall system.

[0023] Among them, the number of tube passes of the first heat exchanger 6 is the same as that of the second heat exchanger 7, the number of tube passes of the third heat exchanger 8 is the same as that of the fourth heat exchanger 9, and the number of tube passes of the third heat exchanger 8 is greater than that of the first heat exchanger 6; the number of tube passes of the third heat exchanger 8 is at least twice that of the first heat exchanger 6. By setting heat exchangers with different numbers of tube passes, high-temperature steam can be effectively diverted, and the high-temperature tolerance of the overall system can be effectively enhanced.

[0024] The outlet ends of the first heat exchanger 6, the second heat exchanger 7, the third heat exchanger 8, and the fourth heat exchanger 9 are all equipped with steam traps 23. The steam traps 23 can separate gas and liquid, thus retaining the liquid and discharging the gas. The outlet ends of the first heat exchanger 6 and the second heat exchanger 7 are jointly connected and communicated with a first steam outlet pipe 10. The outlet ends of the third heat exchanger 8 and the fourth heat exchanger 9 are jointly connected and communicated with a second steam outlet pipe 11. The first steam outlet pipe 10 and the second steam outlet pipe 11 are jointly connected to a water collection device 12. The gas outlet end of the water collection device 12 is connected to an exhaust pipe 13. An air flow valve 24 is installed on the exhaust pipe 13. The air flow valve 24 can control the air flow rate through the exhaust pipe 13. The outlet end of the exhaust pipe 13 is installed with a flow guide cylinder 25 to further accelerate the exhaust rate. The water outlet end of the water collection device 12 is connected to a drain pipe 14. A liquid flow valve 26 is installed on the drain pipe 14. The liquid flow valve 26 can control the liquid flow rate of the drain pipe 14. The outlet end of the drain pipe 14 is communicated with a water storage bucket 27. The water storage bucket 27 can further store the aqueous solution flowing out of the system.

[0025] The working principle of the present utility model is as follows:

[0026] High-temperature steam can enter the system through the steam inlet pipe 1 and can enter the first heat exchanger 6, the second heat exchanger 7, the third heat exchanger 8, and the fourth heat exchanger 9 through the first steam passing pipe 2, the second steam passing pipe 3, the third steam passing pipe 4, and the fourth steam passing pipe 5 respectively for heat exchange. After the high-temperature steam completes heat exchange, the steam-water mixture flowing out of the first heat exchanger 6 and the second heat exchanger 7 can be separated into gas under the action of the steam trap 23 and enter the first steam outlet pipe 10. The steam-water mixture flowing out of the third heat exchanger 8 and the fourth heat exchanger 9 can be separated into gas under the action of the steam trap 23 and enter the second steam outlet pipe 11. The gas in the first steam outlet pipe 10 and the second steam outlet pipe 11 can jointly flow into the water collection device 12, so as to further separate gas and liquid. The separated gas is dispersed into the air through the flow guide cylinder 25, and the separated liquid flows into the water storage bucket 27.

[0027] In the above heat exchange process, due to the setting of multiple steam passing pipes and multiple heat exchangers, the pressure tolerance strength of the overall heat exchange system can be effectively improved, the control ability of the steam passing pipes and the steam outlet pipes can be enhanced, so as to improve the adjustable ability of the overall heat exchange system, ensure the smooth drainage of each heat exchanger, and further ensure the normal operation of the overall heat exchange system.

[0028] The above description of the disclosed embodiments enables those skilled in the art to implement or use the present utility model. Various modifications to these embodiments will be obvious to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present utility model. Therefore, the present utility model will not be limited to these embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A heat exchange system for a coal-fired boiler, comprising a steam inlet pipe (1), characterized in that, The steam inlet pipe (1) is connected to a first steam passing pipe (2), a second steam passing pipe (3), a third steam passing pipe (4), and a fourth steam passing pipe (5). Control valve groups are provided on the pipelines of the first steam passing pipe (2), the second steam passing pipe (3), the third steam passing pipe (4), and the fourth steam passing pipe (5). The outlet ends of the first steam passing pipe (2), the second steam passing pipe (3), the third steam passing pipe (4), and the fourth steam passing pipe (5) are respectively connected to a first heat exchanger (6), a second heat exchanger (7), a third heat exchanger (8), and a fourth heat exchanger (9). The outlet ends of the first heat exchanger (6) and the second heat exchanger (7) jointly converge and are connected to a first steam outlet pipe (10). The outlet ends of the third heat exchanger (8) and the fourth heat exchanger (9) jointly converge and are connected to a second steam outlet pipe (11). The first steam outlet pipe (10) and the second steam outlet pipe (11) are jointly connected to a water collecting device (12). The gas outlet end of the water collecting device (12) is connected to an exhaust pipe (13). The water outlet end of the water collecting device (12) is connected to a drain pipe (14).

2. The heat exchange system for a coal-fired boiler according to claim 1, characterized in that, Each of the control valve groups includes a first stop valve (15) connected to the first steam passing pipe (2), the second steam passing pipe (3), the third steam passing pipe (4), and the fourth steam passing pipe (5). An electric control valve (16) is installed at the outlet end of the first stop valve (15). A second stop valve (17) is installed at the outlet end of the electric control valve (16).

3. A heat exchange system for a coal-fired boiler according to claim 1, characterized in that, A first direct pipe (18), a second direct pipe (19), a third direct pipe (20), and a fourth direct pipe (21) are respectively connected in parallel to the first steam passing pipe (2), the second steam passing pipe (3), the third steam passing pipe (4), and the fourth steam passing pipe (5). The outlet ends of the first direct pipe (18), the second direct pipe (19), the third direct pipe (20), and the fourth direct pipe (21) are respectively connected to the first heat exchanger (6), the second heat exchanger (7), the third heat exchanger (8), and the fourth heat exchanger (9). A third stop valve (22) is installed on the pipelines of the first direct pipe (18), the second direct pipe (19), the third direct pipe (20), and the fourth direct pipe (21).

4. A heat exchange system for a coal-fired boiler according to claim 1, characterized in that The first heat exchanger (6) and the second heat exchanger (7) have the same number of tube passes. The third heat exchanger (8) and the fourth heat exchanger (9) have the same number of tube passes. The number of tube passes of the third heat exchanger (8) is greater than that of the first heat exchanger (6).

5. A heat exchange system for a coal-fired boiler according to claim 4, characterized in that, The number of tube passes of the third heat exchanger (8) is at least twice that of the first heat exchanger (6).

6. The heat exchange system for a coal-fired boiler according to claim 4, wherein, Steam traps (23) are installed at the outlet ends of the first heat exchanger (6), the second heat exchanger (7), the third heat exchanger (8), and the fourth heat exchanger (9).

7. A heat exchange system for a coal-fired boiler according to claim 1, characterized in that, An air flow valve (24) is installed on the exhaust pipe (13). A guide cylinder (25) is installed at the outlet end of the exhaust pipe (13).

8. A heat exchange system for a coal-fired boiler according to claim 1, characterized in that, A liquid flow valve (26) is installed on the drain pipe (14). The outlet end of the drain pipe (14) is connected to a water receiving bucket (27).

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