High-energy drain water recycling system for once-through boiler

Abstract

The invention provides a high-energy drain recycling system for a once-through boiler, which comprises a drain flash tank and a deaerator, and further comprises a first pipeline, a second pipeline, a third pipeline, a fourth pipeline, a cooling water conveying pipeline and a blow-off pipeline, the first water inlet is connected to an overflow header pipe of the water storage tank through a first pipeline, the steam exhaust port is connected to the deaerator through a second pipeline, and the water outlet is connected to the deaerator through a third pipeline. Saturated steam is decompressed and expanded in the deaerator, saturated water is subjected to secondary steam-water separation in the deaerator, and the saturated steam and the saturated water which are finally generated in the deaerator are used for heating condensed water, so that heat of high-energy drain water is effectively recycled, waste caused by direct discharge of the high-energy drain water is avoided, energy is saved, and the deaerator has the remarkable advantages of consumption reduction and emission reduction.

Description

Technical Field

[0001] The invention relates to the technical field of direct-flow boilers, and in particular to a high-energy drain recovery and utilization system for direct-flow boilers. Background Art

[0002] A critical direct-current boiler is a boiler in which the pressure of the working fluid in the boiler is above the critical point. The working fluid parameters of a supercritical boiler reach or exceed the critical pressure and critical temperature of water. At this pressure and temperature, the density of water and steam is the same. Supercritical direct-current boilers usually adopt direct-current operation mode, that is, the feed water passes through the boiler once, passes through the heating, evaporation and superheating heating surfaces in sequence, and generates superheated steam with a certain pressure and temperature. Supercritical direct-current boilers have become the main force of my country's thermal power units, and there are many projects under construction. A direct-current boiler refers to a boiler that relies on the pressure of the feed water pump to make the feed water pass through the economizer, evaporation heating surface, and superheater in sequence and all become superheated steam. Since the feed water enters the boiler, the heating, evaporation and superheating of the water vapor are all carried out continuously in the heating surface, and there is no need to separate the steam and water in the middle of the heating. Therefore, it does not have the steam drum of a natural circulation boiler, and there is no fixed dividing point between the economizer heating surface, the evaporation heating surface and the superheater heating surface, which changes with the change of boiler load.

[0003] Existing supercritical direct current boilers are usually equipped with a water tank. The capacity of the water tank is relatively limited, so an external overflow main is usually connected. When the water tank is full of water, excess water will be directly discharged from the overflow main. Since the discharged water is high-energy hydrophobic, a certain degree of waste will be caused, which is not in line with the concept of energy conservation and environmental protection. Summary of the invention

[0004] In view of this, in order to solve the problem in the technical background that the existing supercritical direct-current boiler is usually provided with a water storage tank, the capacity of the water storage tank is relatively limited, so it is usually connected to an external overflow main pipe. When the water storage tank is full of water, the excess water will be directly discharged from the overflow main pipe. Since the discharged water is high-energy drainage, a certain degree of waste will be formed. A high-energy drainage recovery and utilization system for direct-current boilers is proposed, and the specific technical scheme is as follows:

[0005] A high-energy drain recovery and utilization system for a direct-current boiler comprises a drain expansion tank and a deaerator, and also comprises a first pipeline, a second pipeline, a third pipeline, a fourth pipeline, a cooling water delivery pipeline and a sewage pipeline. The drain expansion tank 1 is provided with a first water inlet, a steam outlet and a drain outlet. The first water inlet is connected to a water tank overflow main pipe through a first pipeline, the steam outlet is connected to the deaerator through a second pipeline, and the drain outlet is connected to the deaerator through a third pipeline.

[0006] In one embodiment of the present invention, a first regulating valve, a first electric shut-off valve and a first manual shut-off valve are disposed on the first pipeline, and a first electric shut-off valve and a first manual shut-off valve are disposed on both sides of the first regulating valve.

[0007] In one embodiment of the present invention, the second pipeline is provided with a second regulating valve, a second manual shut-off valve, a second electric shut-off valve and a first check valve, the second pipeline is provided with a second manual shut-off valve and a second electric shut-off valve on both sides of the second regulating valve, respectively, and the second pipeline is provided with a first check valve between the second electric shut-off valve and the deaerator.

[0008] In one embodiment of the present invention, the third pipeline is provided with a third regulating valve, a third manual shut-off valve, a third electric shut-off valve, a second check valve and a fifth manual shut-off valve. The third regulating valve adjusts the pressure. The third pipeline is provided with a third manual shut-off valve and a third electric shut-off valve on both sides of the third regulating valve. The third electric shut-off valve can block the pipeline when necessary, and the third manual shut-off valve can manually block the pipeline when the third electric shut-off valve fails or malfunctions.

[0009] In one embodiment of the present invention, a second check valve is provided in the third pipeline between the third electric shut-off valve and the deaerator, and the second check valve can prevent the backflow of saturated water transported to the deaerator. A fifth manual shut-off valve is provided in the third pipeline between the third electric shut-off valve and the second check valve, and the fifth manual shut-off valve can manually block the pipeline between the second check valve and the deaerator to cooperate with the sewage discharge operation of the following sewage pipeline.

[0010] In one embodiment of the present invention, a second water inlet is provided on the hydrophobic expansion tank, and the second water inlet is connected to the cooling water delivery pipeline through a fourth pipeline. A cooling water spray device is provided inside the hydrophobic expansion tank, and the cooling water spray device is connected to the second water inlet.

[0011] In one embodiment of the present invention, the fourth pipeline includes a fourth regulating valve, a fourth electric shut-off valve and a fourth manual shut-off valve, and the fourth pipeline is provided with a fourth electric shut-off valve and a fourth manual shut-off valve on both sides of the fourth regulating valve.

[0012] In one embodiment of the present invention, one end of the sewage pipeline is connected to the third pipeline through a three-way joint, and the other end of the sewage pipeline is connected to the outlet pipe of the startup drainage pump.

[0013] In one embodiment of the present invention, the system further comprises a first bypass valve, which forms a bypass relative to the pipeline from the first electric shut-off valve to the first regulating valve and then to the first manual shut-off valve. When the valve body fails or there is other emergency, the first bypass valve can be opened and the first electric shut-off valve or the first manual shut-off valve can be closed at the same time, so that the drain does not pass through the first electric shut-off valve, the first regulating valve and the first manual shut-off valve, but directly flows into the drain expansion tank 1, thereby playing a role of emergency protection.

[0014] In one embodiment of the present invention, a sixth electric shut-off valve and a sixth manual shut-off valve are provided on the sewage pipeline.

[0015] The above technical solution has the following beneficial effects:

[0016] The present invention is provided with a hydrophobic expansion tank and a deaerator. The overflow main pipe of the water tank is connected with the hydrophobic expansion tank through a first pipeline. The high-energy hydrophobic enters the newly added hydrophobic expansion tank after being decompressed. The high-energy hydrophobic realizes steam-water separation in the hydrophobic expansion tank and can be separated into saturated steam and saturated water. The separated saturated steam enters the steam space of the deaerator after being decompressed through a second pipeline. The separated saturated water enters the water space of the deaerator after being decompressed through a third pipeline. The saturated steam and saturated water can be used as heating heat sources for the deaerator. The saturated steam is decompressed and expanded inside the deaerator. The saturated water is subjected to secondary steam-water separation inside the deaerator. The saturated steam and saturated water finally generated inside the deaerator are used to heat condensed water, effectively recover the heat of the high-energy hydrophobic, avoid the waste caused by direct discharge of the high-energy hydrophobic, save energy, and have the significant advantages of reducing consumption and emission. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a structural schematic diagram of a high-energy drain recovery and utilization system for a once-through boiler according to the present invention;

[0018] In the figure: 1. Drain expansion tank; 11. First water inlet; 12. Steam exhaust port; 13. Drain port; 14. Second water inlet; 2. Deaerator;

[0019] 3. Water tank overflow main pipe; 4. First pipeline; 41. First regulating valve; 42. First electric shut-off valve; 43. First manual shut-off valve; 5. Second pipeline; 51. Second regulating valve; 52. Second manual shut-off valve; 53. Second electric shut-off valve; 54. First check valve; 6. Third pipeline; 61. Third regulating valve; 62. Third manual shut-off valve; 63. Third electric shut-off valve; 64. Second check valve; 65. Fifth manual shut-off valve; 7. Cooling water delivery pipeline; 8. Fourth pipeline; 81. Fourth regulating valve; 82. Fourth electric shut-off valve; 83. Fourth manual shut-off valve. DETAILED DESCRIPTION

[0020] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0021] Example 1: See Figure 1 A supercritical once-through boiler drain recovery system shown in the figure comprises a drain expansion tank 1 and a deaerator 2. The drain expansion tank 1 is provided with a first water inlet 11, a steam outlet 12 and a water outlet 13. The first water inlet 11 is connected to a water tank overflow main pipe 3 through a first pipeline 4, the steam outlet 12 is connected to the deaerator 2 through a second pipeline 5, and the water outlet 13 is connected to the deaerator 2 through a third pipeline 6.

[0022] The water tank overflow main pipe 3 is preferably connected to the first pipeline 4 by setting a tee to lead out high-energy drain. The pressure of the high-energy drain transported by the water tank overflow main pipe 3 is preferably 8MPa.a, and the drain volume is preferably 90t / h. The newly added drain expansion tank 1 is connected to the water tank overflow main pipe 3 through the first pipeline 4. The high-energy drain enters the drain expansion tank 1 after decompression. The working pressure of the drain expansion tank 1 is preferably set to 0.8MPa.a. The high-energy drain realizes steam-water separation in the drain expansion tank 1 and can be separated into 26t / h of saturated steam and 64t / h of saturated water. The separated saturated steam enters the steam space of the deaerator 2 after decompression through the second pipeline 5. The pressure after compression is preferably 0.42MPa.a. The saturated water after separation enters the water space of the deaerator 2 through the third pipeline 6 after decompression. The pressure after decompression is preferably 0.42MPa.a. The saturated steam and saturated water can be used as heating heat sources for the deaerator 2. The 26t / h saturated steam is decompressed and expanded inside the deaerator 2. The 64t / h saturated water is subjected to secondary steam-water separation inside the deaerator 2. Finally, 30t / h saturated steam and 60t / h saturated water are generated inside the deaerator 2 for heating condensed water, effectively recovering the heat of high-energy hydrophobicity, avoiding waste caused by direct discharge of high-energy hydrophobicity, saving energy, and having the significant advantages of reducing consumption and emission.

[0023] The volume of the hydrophobic expansion tank 1 is preferably 10m3, the design pressure of the hydrophobic expansion tank 1 is preferably 1.6MPa.g, the design temperature is preferably 300°C, and the cylinder diameter is preferably 2m;

[0024] In this embodiment, the drain expansion tank 1 is arranged at the 31.40m layer to the upper right of the deaerator 2, and the existing deaerator 2 is arranged at the 24.40m layer in front of the furnace frame. The gravity self-flow is arranged here, which is conducive to high-energy draining to reduce the vibration caused by the two-phase flow of the medium in the pipeline. An operation and maintenance platform can also be added around the drain expansion tank 1 to facilitate the inspection and maintenance of equipment and valves.

[0025] In this embodiment, a first regulating valve 41 is provided on the first pipeline 4, and a first electric shut-off valve 42 and a first manual shut-off valve 43 are respectively provided on both sides of the first regulating valve 41. The first regulating valve 41 can adjust the pressure, the first electric shut-off valve 42 can block the pipeline when necessary, and the first manual shut-off valve 43 can manually block the pipeline when the first electric shut-off valve 42 fails or fails. In addition, a first bypass valve can be preferably provided. The first bypass valve forms a bypass with respect to the pipeline from the first electric shut-off valve 42 to the first regulating valve 41 and then to the first manual shut-off valve 43. When the above valve body fails or there is other emergency situation, the first bypass valve can be opened, and the first electric shut-off valve 42 or the first manual shut-off valve 43 can be closed at the same time, so that the drain does not pass through the first electric shut-off valve 42, the first regulating valve 41 and the first manual shut-off valve 43, and directly flows into the drain expansion tank 1, thereby playing a role of emergency protection.

[0026] In this embodiment, a second regulating valve 51 is provided on the second pipeline 5, and the second regulating valve 51 can adjust the pressure. The second pipeline 5 is provided with a second manual shut-off valve 52 and a second electric shut-off valve 53 on both sides of the second regulating valve 51, respectively. The second electric shut-off valve 53 can block the pipeline when necessary, and the second manual shut-off valve 52 can manually block the pipeline when the second electric shut-off valve 53 fails or fails. The second pipeline 5 is provided with a first check valve 54 between the second electric shut-off valve 53 and the deaerator 2, and the first check valve 54 can It is enough to prevent the backflow of saturated steam transported to the deaerator 2. In addition, a second bypass valve may be preferably provided. The second bypass valve forms a bypass with respect to the pipeline from the second manual shut-off valve 52 to the second regulating valve 51 and then to the second electric shut-off valve 53. When the above-mentioned valve body fails or there is other emergency situation, the second bypass valve can be opened and the second electric shut-off valve 53 or the second manual shut-off valve 52 can be closed at the same time, so that the saturated steam does not pass through the second manual shut-off valve 52, the second regulating valve 51 and the second electric shut-off valve 53, but directly flows into the deaerator 2, thereby playing a role of emergency protection.

[0027] In this embodiment, the third pipeline 6 is provided with a third regulating valve 61, and the third regulating valve 61 can adjust the pressure. The third pipeline 6 is provided with a third manual shut-off valve 62 and a third electric shut-off valve 63 on both sides of the third regulating valve 61, respectively. The third electric shut-off valve 63 can block the pipeline when necessary, and the third manual shut-off valve 62 can manually block the pipeline when the third electric shut-off valve 63 fails or malfunctions. The third pipeline 6 is provided with a second check valve 64 between the third electric shut-off valve 63 and the deaerator 2, and the second check valve 64 can prevent the saturated water delivered to the deaerator 2 from flowing back. The third pipeline 6 is provided with a fifth Manual shut-off valve 65, the fifth manual shut-off valve 65 can manually block the pipeline between the second check valve 64 and the deaerator 2 to cooperate with the sewage discharge operation of the sewage pipeline 9 described below. In addition, a third bypass valve may be preferably provided. The third bypass valve forms a bypass with respect to the pipeline from the third manual shut-off valve 62 to the third regulating valve 61 and then to the third electric shut-off valve 63. When the above-mentioned valve body fails or there are other emergencies, the third bypass valve can be opened and the third electric shut-off valve 63 or the third manual shut-off valve 62 can be closed at the same time, so that the saturated water does not pass through the third manual shut-off valve 62, the third regulating valve 61 and the third electric shut-off valve 63, but directly flows into the deaerator 2, thereby playing a role in emergency protection.

[0028] In this embodiment, since the existing drain expansion tank 1 will have an internal temperature that is too high when it is operated for a long time, which seriously affects the operating efficiency and causes danger, the supercritical direct current boiler drain recovery system also includes a cooling water delivery pipeline 7, which is used to deliver cooling water to the drain expansion tank 1 to cool the inside of the drain expansion tank 1. The drain expansion tank 1 is preferably provided with a second water inlet 14, and the second water inlet 14 is connected to the cooling water delivery pipeline 7 through a fourth pipeline 8. A cooling water spray device is provided inside the drain expansion tank 1, and the cooling water spray device is connected to the second water inlet 14. The cooling water spray device can It is preferably composed of parts such as pipelines and nozzles, and the pipelines and nozzles can be arranged in three layers of upper, middle and lower layers, so that a larger volume can be covered inside the hydrophobic expansion tank 1 for cooling operations. The cooling water delivery pipeline 7 is connected to the external cooling water supply equipment, and the external cooling water supply equipment can deliver high-quality cooling water to the cooling water delivery pipeline 7. The cooling water is delivered to the interior of the hydrophobic expansion tank 1 after passing through the cooling water delivery pipeline 7 and the fourth pipeline 8 for cooling operations, effectively reducing the internal temperature of the hydrophobic expansion tank 1. At the same time, since the delivered cooling water is high-quality cooling water, it can be directly integrated into the saturated steam and saturated water of the hydrophobic expansion tank 1 and directly utilized.

[0029] As an optional implementation, a fourth regulating valve 81 is provided on the fourth pipeline 8, and the fourth regulating valve 81 can adjust the pressure. The fourth pipeline 8 is provided with a fourth electric shut-off valve 82 and a fourth manual shut-off valve 83 on both sides of the fourth regulating valve 81, respectively. The fourth electric shut-off valve 82 can block the pipeline when necessary, and the fourth manual shut-off valve 83 can manually block the pipeline when the fourth electric shut-off valve 82 fails or malfunctions. In addition, a fourth bypass valve may be preferably provided, and the fourth bypass valve forms a bypass with respect to the pipeline from the fourth electric shut-off valve 82 to the fourth regulating valve 81 and then to the fourth manual shut-off valve 83. When the above-mentioned valve body fails or there is other emergency situation, the fourth bypass valve can be opened, and the fourth electric shut-off valve 82 or the fourth manual shut-off valve 83 can be closed at the same time, so that the cooling water does not pass through the fourth electric shut-off valve 82, the fourth regulating valve 81 and the fourth manual shut-off valve 83, and directly flows into the drain expansion tank 1, thereby playing a role of emergency protection.

[0030] In this embodiment, a sewage pipeline 9 is also included. One end of the sewage pipeline 9 is connected to the third pipeline 6 through a three-way joint, and the other end of the sewage pipeline 9 is connected to the outlet pipeline of the startup drainage pump. A sixth electric shut-off valve 91 and a sixth manual shut-off valve 92 are arranged on the sewage pipeline 9. When the water quality of the saturated water delivered from the hydrophobic expansion tank 1 does not meet the standard, the fifth manual shut-off valve 65 can be closed to block the pipeline between the second check valve 64 and the deaerator 2, and the sixth electric shut-off valve 91 or the sixth manual shut-off valve 92 can be opened to connect the fourth pipeline 8 with the sewage pipeline 9, and the saturated water that does not meet the standard can be discharged from the outlet pipeline of the startup drainage pump. When the water quality meets the standard again, the sixth electric shut-off valve 91 or the sixth manual shut-off valve 92 can be closed to block the fourth pipeline 8 with the sewage pipeline 9, and the fifth manual shut-off valve 65 can be opened to re-form a passage in the pipeline between the second check valve 64 and the deaerator 2, so that the saturated water can be normally delivered to the deaerator 2.

[0031] The basic principles and main features of the present invention are described above. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The above embodiments and descriptions are only for illustrating the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, which shall fall within the scope of the present invention to be protected. The scope of protection of the invention shall be defined by the attached claims and their equivalents.

Claims

1. A high-energy drain recovery system for a once-through boiler, characterized in that: It includes a hydrophobic expansion tank and a deaerator, and also includes a first pipeline, a second pipeline, a third pipeline, a fourth pipeline, a cooling water delivery pipeline and a sewage pipeline. The hydrophobic expansion tank is provided with a first water inlet, a steam outlet and a water outlet. The first water inlet is connected to the overflow main pipe of the water storage tank through a first pipeline, the steam outlet is connected to the deaerator through a second pipeline, and the water outlet is connected to the deaerator through a third pipeline.

2. A high-energy drain recovery and utilization system for a once-through boiler according to claim 1, characterized in that: The first pipeline is provided with a first regulating valve, a first electric shut-off valve and a first manual shut-off valve. The first pipeline is provided with a first electric shut-off valve and a first manual shut-off valve on both sides of the first regulating valve.

3. The high-energy drain recovery system for a once-through boiler according to claim 1 is characterized in that: The second pipeline is provided with a second regulating valve, a second manual shut-off valve, a second electric shut-off valve and a first check valve. The second pipeline is provided with a second manual shut-off valve and a second electric shut-off valve on both sides of the second regulating valve respectively. The second pipeline is provided with a first check valve between the second electric shut-off valve and the deaerator.

4. The high-energy drain recovery system for a once-through boiler according to claim 1 is characterized in that: The third pipeline is provided with a third regulating valve, a third manual shut-off valve, a third electric shut-off valve, a second check valve and a fifth manual shut-off valve. The third regulating valve adjusts the pressure. The third pipeline is provided with a third manual shut-off valve and a third electric shut-off valve on both sides of the third regulating valve. The third electric shut-off valve can block the pipeline when necessary. The third manual shut-off valve can manually block the pipeline when the third electric shut-off valve fails or malfunctions.

5. A high-energy drain recovery system for a once-through boiler according to claim 1 or 4, characterized in that: The third pipeline is provided with a second check valve between the third electric shut-off valve and the deaerator, and the second check valve can prevent the backflow of saturated water transported to the deaerator. The third pipeline is provided with a fifth manual shut-off valve between the third electric shut-off valve and the second check valve, and the fifth manual shut-off valve can manually block the pipeline between the second check valve and the deaerator to cooperate with the sewage discharge operation of the following sewage pipeline.

6. The high-energy drain recovery and utilization system for once-through boiler according to claim 1 is characterized in that: The hydrophobic expansion tank is provided with a second water inlet, which is connected to the cooling water delivery pipeline through a fourth pipeline. A cooling water spray device is provided inside the hydrophobic expansion tank, and the cooling water spray device is connected to the second water inlet.

7. The high-energy drain recovery system for a once-through boiler according to claim 1 is characterized in that: The fourth pipeline includes a fourth regulating valve, a fourth electric shut-off valve and a fourth manual shut-off valve. The fourth pipeline is provided with a fourth electric shut-off valve and a fourth manual shut-off valve on both sides of the fourth regulating valve.

8. The high-energy drain recovery and utilization system for once-through boiler according to claim 1 is characterized in that: One end of the sewage discharge pipeline is connected to the third pipeline through a three-way joint, and the other end of the sewage discharge pipeline is connected to the outlet pipeline of the start-up drainage pump.

9. The high-energy drain recovery and utilization system for once-through boiler according to claim 1 is characterized in that: The system also includes a first bypass valve, which forms a bypass relative to the pipeline from the first electric shut-off valve to the first regulating valve and then to the first manual shut-off valve. When the above valve body fails or there is other emergency situation, the first bypass valve can be opened and the first electric shut-off valve or the first manual shut-off valve can be closed at the same time, so that the drain does not pass through the first electric shut-off valve, the first regulating valve and the first manual shut-off valve, but directly flows into the drain expansion tank 1, which plays a role of emergency protection.

10. The high-energy drain recovery and utilization system for once-through boiler according to claim 1, characterized in that: The sewage pipeline is provided with a sixth electric shut-off valve and a sixth manual shut-off valve.

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