Feed water heat regeneration device of steam turbine

Abstract

The utility model discloses a water supply heat regeneration device of a steam turbine, which relates to the technical field of electric power and comprises a steam turbine set, a second high-pressure heater and a steam extraction check valve electromagnetic valve, a steam extraction check valve is arranged on the outer side of the steam turbine set, and one end of the steam extraction check valve is connected with a second gas conveying pipe fitting. A first high-pressure heater is arranged on one side of the steam turbine unit, a second high-pressure heater is arranged at the other end of the first high-pressure heater, and a third high-pressure heater is arranged on the other side of the second high-pressure heater. The high-pressure heater II is technically improved from original random starting to furnace starting, so that the starting speed of the unit is increased; when the other two high-pressure heaters are put into operation, heating can be achieved without large temperature difference, starting is better than random starting, the service life of the high-pressure heaters is greatly prolonged, the feed water temperature is improved, the stress of the heating surface of the boiler is greatly reduced, the use amount of fuel is reduced, the use amount of auxiliary steam in the initial stage of unit starting is reduced, and the safety of plant steam is improved.

Description

Technical Field

[0001] This utility model relates to the technical field of power, specifically to a feedwater regeneration device for a steam turbine. Background Technology

[0002] At present, the high-pressure heaters of thermal power generating units generally adopt random slip start, that is, after the turbine starts, the steam inlet non-return valves and electric valves of each high-pressure heater are opened to heat the feedwater, realize the regenerative cycle, and improve the power generation efficiency. After the turbine trips, in order to prevent cold water and cold steam from entering the internal system, the extraction non-return valves and electric valves of each stage are interlocked and closed. Before the turbine is re-energized, all extraction non-return valves and electric valves are locked and prohibited from being opened. During the normal start-up of the unit, the feedwater can only be heated through the deaerator. When the quality of the deaerator feedwater meets the requirements of the boiler feedwater quality, water is supplied to the boiler.

[0003] When the high-pressure heater adopts random slip-start (the No. 2 high-pressure heater cannot be put into operation before the turbine is engaged), during the unit's startup, temperature and pressure rise, steam can only be supplied from the auxiliary steam or water can be circulated back and forth through the NWL valve to the deaerator to heat the feedwater, which is limited by the deaerator's heating capacity. At the same time, as the feedwater flows through the entire high-pressure heater system, its temperature will decrease due to heat dissipation from the equipment. To obtain steam with the same parameters, an increase in fuel quantity is required. Because the feedwater temperature is low, the combustion conditions in the furnace are relatively unstable, prolonging the unit's startup time. In addition, under the random start-up mode of the high-pressure heater, steam with certain parameters is only available to heat the feedwater when the turbine reaches 2400 RPM, further extending the unit's startup time. Summary of the Invention

[0004] The purpose of this invention is to provide a feedwater regeneration device for steam turbines to solve the aforementioned defects caused by the prior art.

[0005] A feedwater regeneration device for a steam turbine includes a steam turbine unit, a second high-pressure heater, and an extraction non-return valve solenoid valve. An extraction non-return valve is installed on the outside of the steam turbine unit. One end of the extraction non-return valve is connected to a second gas transmission pipe. A first high-pressure heater is installed on one side of the steam turbine unit. A second high-pressure heater is installed at the other end of the first high-pressure heater. A third high-pressure heater is installed on the other side of the second high-pressure heater. The other end of the second gas transmission pipe is connected to the input terminal of the third high-pressure heater.

[0006] Preferably, the steam turbine unit is connected to one end of the gas transmission pipe through a non-return valve solenoid valve provided on one side, and the other end of the gas transmission pipe is connected to the input end of a high-pressure heater.

[0007] Preferably, the high-pressure heater 2 is connected to the inlet valve via an inlet pipe connected to its top end.

[0008] Preferably, the outer side of the high-pressure heater is connected to the input end of an air pilot valve.

[0009] Preferably, the air pilot valve is connected to a manual air valve via an externally connected compressed air pipeline.

[0010] Preferably, the liquid inlet valve is connected to the liquid inlet pipe via a cylinder located at the top, and the cylinder performs opening and closing operations on the valve core of the liquid inlet valve.

[0011] Compared with the prior art, the present invention has the following advantages:

[0012] 1. The high-pressure heater II was changed from random start-up to start-up with the boiler, which speeds up the unit's start-up. After the unit is started up, the other two high-pressure heaters can heat without a large temperature difference when put into operation, which is better than random start-up. This is of great benefit to extending the service life of the high-pressure heaters, improving feedwater temperature, and greatly reducing the stress on the boiler's heating surface. For the enterprise, it reduces fuel consumption, reduces auxiliary steam consumption during the initial start-up of the unit, improves the safety of plant steam, and better controls feedwater temperature, allowing the high-pressure heater pipes to achieve a reasonable temperature rise and extending the service life of the high-pressure heaters.

[0013] 2. The No. 2 high-pressure heater was started up along with the boiler, which improved the commissioning speed of the entire regenerative system. After the unit is connected to the grid, it is beneficial to put the high-pressure heater system into operation as soon as possible, thereby improving the efficiency of the entire power generation cycle. Due to the increase in feedwater temperature, the furnace temperature and flue gas temperature also increase, allowing the denitrification SCR reactor to be put into operation earlier, reducing NOx emissions and pollutant emissions. The shortened unit start-up time also reduces the workload of the operating personnel.

[0014] 3. The feedwater temperature when No. 2 high-pressure heater is put into operation is 145℃. Before the power grid is connected, the feedwater temperature reaches 180℃. After No. 2 high-pressure heater is put into operation, the feedwater temperature rises by 35℃. The time for No. 2 high-pressure heater to be put into operation is from the reheater pressure rise to the main unit running at 2400RPM, which takes about 2.5 hours. The cumulative feedwater flow is about 1625t, the average feedwater temperature rise is 35℃, and the total heat recovered is: (763-611)X1625X1000=247000000kJ;

[0015] 4. Saving standard coal: (247,000,000 / 29,307) / 1000 = 8.43t. Calculated at 1200 yuan / ton for standard coal, the cost saving is: 8.43 x 1200 = 10,100 yuan. (2) Using No. 2 high-pressure heater for boiler start-up can shorten the unit start-up time by about 1.5 hours. Calculated at a direct plant power consumption rate of 35,000 kWh / hour, the cost saving is calculated at 0.48 yuan / kWh, resulting in a cost saving of 16,800 yuan. The total cost saving for each unit start-up is 26,900 yuan. Assuming 8 unit starts-ups per year, the annual cost saving is 215,200 yuan, demonstrating significant energy-saving effects. Attached Figure Description

[0016] Figure 1 This is a three-dimensional structural diagram of the present invention.

[0017] in:

[0018] 1. Steam turbine unit; 2. Steam extraction non-return valve; 3. Gas transmission pipe fitting one; 4. Gas transmission pipe fitting two; 5. High-pressure heater one; 6. High-pressure heater two; 7. Liquid inlet pipe fitting; 8. Liquid inlet valve; 9. Compressed air pipeline; 10. Cylinder; 11. Manual air valve; 12. High-pressure heater three; 13. Air pilot valve; 14. Solenoid valve. Detailed Implementation

[0019] To make the technical means, creative features, objectives and effects of this utility model easier to understand, the present utility model will be further described below in conjunction with specific embodiments.

[0020] like Figure 1 As shown, a feedwater regeneration device for a steam turbine includes a steam turbine unit 1, a second high-pressure heater 6, an extraction non-return valve 2, and a solenoid valve 14. The extraction non-return valve 2 is installed on the outside of the steam turbine unit 1. One end of the extraction non-return valve 2 is connected to a second gas transmission pipe 4. A first high-pressure heater 5 is installed on one side of the steam turbine unit 1. The second high-pressure heater 6 is installed on the other end of the first high-pressure heater 5. A third high-pressure heater 12 is installed on the other side of the second high-pressure heater 6. The other end of the second gas transmission pipe 4 is connected to the input end of the third high-pressure heater 12.

[0021] In this embodiment, the steam turbine unit 1 is connected to one end of the gas transmission pipe 3 via a solenoid valve 14 installed on the extraction non-return valve 2 on one side. The other end of the gas transmission pipe 3 is connected to the input end of the high-pressure heater 5. The solenoid valve 14 automatically injects and closes the steam.

[0022] In this embodiment, the high-pressure heater 6 is connected to the liquid inlet valve 8 via a liquid inlet pipe 7 at its top end. Cold water is directly injected into the interior of the high-pressure heater 6 through the liquid inlet pipe 7.

[0023] In this embodiment, the input terminal of the air pilot valve 13 is connected to the outside of the high-pressure heater 6.

[0024] In this embodiment, the air pilot valve 13 is connected to the manual air valve 11 via the compressed air pipeline 9 connected to the outside, and high-temperature steam is injected through the compressed air pipeline 9 to heat the liquid in the high-pressure heater 6.

[0025] In this embodiment, the liquid inlet valve 8 is connected to the liquid inlet pipe 7 via a cylinder 10 located at the top, and the cylinder 10 performs opening and closing operations on the valve core of the liquid inlet valve 8.

[0026] In practical applications, the feedwater regeneration device for this type of steam turbine includes the following operations:

[0027] Step 1: The high-pressure heater 26, which was originally started with the steam turbine unit 1, is now started with the boiler, which speeds up the start-up speed of the steam turbine unit 1; after the steam turbine unit 1 is started, when the other high-pressure heater 15 and high-pressure heater 312 are put into operation, they can heat without a large temperature difference, which is better than random start-up.

[0028] Step 2: Before turbine unit 1 is engaged, the air pilot valve 13 and extraction non-return valve 2 of high-pressure heater 2 6 are not open. Therefore, we need to modify the existing system by adding a manual air valve 11 to control the actuator of extraction non-return valve 2, thus activating high-pressure heater 2 6 to heat the feedwater.

[0029] Step 3: The operator opens the cylinder 10 and uses the cylinder 10 to vertically pull the internal valve core of the liquid inlet valve 8, thereby controlling the liquid inlet volume of the liquid inlet valve 8, and injecting the liquid into the interior of the high-pressure heater 6 through the liquid inlet pipe 7 set on one side.

[0030] Step 4: To activate the high-pressure heater 26 before the turbine is tripped, a separate compressed air pipeline 9 needs to be installed from the instrumentation compressed air main pipe and connected to the compressed air pipeline 9 before the control solenoid valve 14 of the extraction non-return valve 2 located outside the high-pressure heater 26. At the same time, a manual air valve 11 should also be installed on the compressed air pipeline 9 from the air pilot valve 13 to the second-stage extraction non-return valve 2. This requires us to modify the existing system by adding a control air source to the compressed air pipeline 9 to inject high-temperature steam into the high-pressure heater 26 to heat the feedwater.

[0031] Therefore, the above-disclosed embodiments are merely illustrative in all respects and are not the only ones. All modifications within the scope of this utility model or its equivalents are included in this utility model.

Claims

1. A feedwater regeneration device for a steam turbine, characterized in that: The system includes a steam turbine unit (1), a second high-pressure heater (6), an extraction non-return valve (2), and a solenoid valve (14). The extraction non-return valve (2) is provided on the outside of the steam turbine unit (1). One end of the extraction non-return valve (2) is connected to a second gas transmission pipe (4). A first high-pressure heater (5) is provided on one side of the steam turbine unit (1). A second high-pressure heater (6) is provided on the other end of the first high-pressure heater (5). A third high-pressure heater (12) is provided on the other side of the second high-pressure heater (6). The other end of the second gas transmission pipe (4) is connected to the input end of the third high-pressure heater (12).

2. The feedwater regeneration device for a steam turbine according to claim 1, characterized in that: The steam turbine unit (1) is connected to one end of the gas transmission pipe (3) through a steam extraction non-return valve (2) and a solenoid valve (14) provided on one side. The other end of the gas transmission pipe (3) is connected to the input end of the high-pressure heater (5).

3. The feedwater regeneration device for a steam turbine according to claim 1, characterized in that: The high-pressure heater (6) is connected to the inlet valve (8) via an inlet pipe (7) at its top.

4. The feedwater regeneration device for a steam turbine according to claim 1, characterized in that: The high-pressure heater 2 (6) is connected to the input end of an air pilot valve (13) on its outer side.

5. A feedwater regeneration device for a steam turbine according to claim 4, characterized in that: The air pilot valve (13) is connected to the manual air valve (11) via the compressed air pipeline (9) connected to the outside.

6. The feedwater regeneration device for a steam turbine according to claim 3, characterized in that: The liquid inlet valve (8) is connected to the liquid inlet pipe (7) through a cylinder (10) set at the top. The cylinder (10) performs opening and closing operations on the valve core of the liquid inlet valve (8).

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