Steam jet vacuum-pumping system of condenser in power plant

Abstract

The utility model relates to a power plant condenser steam jet vacuum-pumping system which comprises a condenser, a water ring vacuum pump, a multi-stage steam ejector, a steam surge tank and a combined type steam condenser, and the condenser is connected with the water ring vacuum pump and a first-stage steam ejector through a pipeline. Power steam passes through the steam surge tank and then is connected into inlets of the multi-stage steam ejectors, the first-stage steam ejector comprises two steam ejectors arranged in parallel, the combined steam condenser comprises multi-stage condensing devices corresponding to the multi-stage steam ejectors in number, and the multi-stage steam ejectors are sequentially connected with the multi-stage condensing devices in series. An inlet of the first-stage condensing device is connected with a cooling water inlet pipe, an outlet of the last-stage condensing device is connected with a cooling water outlet pipe, and the multiple stages of condensing devices return water to the condenser hot well through U-shaped pipes. The originally configured water ring vacuum pump is put into operation only when the machine is started and vacuum is established, the cavitation condition does not exist, the back pressure of the unit can be reduced in the cylinder switching process in winter, and the air blowing influence of a turbine is reduced.

Description

Technical Field

[0001] This utility model relates to the technical field of industrial systems, and in particular to a steam jet vacuum system for a power plant condenser. Background Technology

[0002] Currently, power plants commonly use water ring vacuum pumps and conventional condenser steam jet vacuum systems. However, the following problems exist in actual use: First, in summer, the operating water temperature is high, making cavitation prone to occur, affecting safe and economical operation. Due to its principle and structure, water ring vacuum pumps cannot avoid cavitation under certain operating conditions, especially in summer. When the ambient temperature rises and the temperature of the industrial liquid in the water ring vacuum pump rises to a certain temperature, the absolute pressure of the pumped liquid drops to the vaporization pressure of the liquid at that temperature, causing cavitation. Cavitation not only damages the flow components but also generates noise and vibration, leading to a decline in the pump's performance and an inability to maintain optimal vacuum in the unit. In severe cases, it can cause the pump to stop working, resulting in high maintenance costs and affecting the safe and economical operation of the unit. Second, existing unit vacuum systems consume a lot of energy, affecting the plant's power consumption rate. Third, conventional condenser steam jet vacuum systems cannot achieve the low back pressure required for the turbine's low-pressure cylinder under low-output operating conditions. Utility Model Content

[0003] To address the problems existing in the prior art, this utility model provides a steam jet vacuum system for power plant condensers.

[0004] The present invention provides a steam jet vacuum system for a power plant condenser, which adopts the following technical solution:

[0005] A steam jet vacuum system for a power plant condenser includes a condenser, a water ring vacuum pump, a multi-stage steam ejector, a steam pressure tank, and a combined steam condenser. The condenser is connected to the water ring vacuum pump and the first-stage steam ejector via pipelines. Power steam passes through the steam pressure tank and enters the inlet of the multi-stage steam ejector. The first-stage steam ejector includes two steam ejectors connected in parallel. The combined steam condenser includes a multi-stage condensing device corresponding to the number of multi-stage steam ejectors. The multi-stage steam ejectors and the multi-stage condensing devices are connected in series. The inlet of the first-stage condensing device is connected to a cooling water inlet pipe, and the outlet of the last-stage condensing device is connected to a cooling water outlet pipe. The multi-stage condensing device returns water to the condenser hot well through a U-shaped pipe.

[0006] By adopting the above technical solutions, after the vacuum system modification, the original water ring vacuum pump only operates during startup to establish vacuum. Under normal operating conditions, the water ring vacuum pump remains in standby mode, eliminating the risk of cavitation and equipment damage. Therefore, the original water ring vacuum pump does not require disassembly and maintenance, effectively reducing maintenance frequency. Replacing the currently operating water ring vacuum pump with a steam ejector vacuum system not only improves the unit's vacuum operation under high summer temperatures and eliminates the safety hazards caused by water ring vacuum pump cavitation, but also reduces unit back pressure and turbine blow-off impact during winter cylinder shut-off. Furthermore, it offers significant energy-saving benefits.

[0007] Optionally, the system includes a three-stage steam ejector and a three-stage condenser. The outlet of the first-stage steam ejector is connected to the inlet of the first-stage condenser. The inlet of the second-stage steam ejector is connected to the outlet of the first-stage condenser. The outlet of the second-stage steam ejector is connected to the inlet of the second-stage condenser. The inlet of the third-stage steam ejector is connected to the outlet of the second-stage condenser. The outlet of the third-stage steam ejector is connected to the inlet of the third-stage condenser.

[0008] Optionally, an auxiliary steam pipe for supplying power steam to the second-stage condenser is connected between the first-stage condenser and the second-stage condenser.

[0009] By adopting the above technical solution, the auxiliary steam pipeline is used to transport power steam, ensuring the amount of power steam in the second-stage condenser.

[0010] Optionally, shut-off valves, mechanical pressure reducing valves, pneumatic ball valves, and pneumatic regulating valves may be installed on the pipelines supplying power steam to the steam pressure tank.

[0011] Optionally, a vacuum gate valve, a vacuum flow sight glass, and a pneumatic vacuum butterfly valve are installed on the U-tube.

[0012] Optionally, a vacuum automatic steam trap is also installed on the U-shaped tube connecting to the last stage of the condenser.

[0013] By adopting the above technical solution, the automatic vacuum steam trap is used to balance the pressure difference between atmospheric pressure and the condenser.

[0014] Optionally, drain points are provided on the auxiliary steam pipe and the cooling water inlet pipe.

[0015] Optionally, the cooling water is an open-loop circulating water system and is drawn from the outlet header of the open-loop water pump.

[0016] In summary, this utility model has at least one of the following beneficial technical effects:

[0017] Since the original water ring vacuum pump was only put into operation when the vacuum was established during startup, and was in standby mode for a long time under normal operation, there was no cavitation or equipment damage. Therefore, the original water ring vacuum pump did not need to be disassembled for maintenance, effectively reducing the number of maintenance times.

[0018] Replacing the currently operating water ring vacuum pump with a steam ejector vacuum system not only improves the vacuum operation of the unit under high-temperature conditions in summer, but also solves the safety hazards caused by cavitation of the water ring vacuum pump to the unit operation.

[0019] During winter cylinder cutting, the back pressure of the unit can be reduced, the impact of turbine blowdown can be reduced, and there are also significant energy-saving benefits. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the steam jet vacuum system for a power plant condenser, according to an embodiment of this utility model.

[0021] Explanation of reference numerals in the attached drawings: 1. Condenser; 2. Water ring vacuum pump; 3. Steam ejector; 4. Steam pressure stabilizing tank; 5. Combined steam condenser; 6. Vacuum butterfly valve; 7. Pneumatic vacuum butterfly valve; 8. Check valve; 9. Butterfly valve; 10. Shut-off valve; 11. Mechanical pressure reducing valve; 12. Pneumatic ball valve; 13. Pneumatic regulating valve; 14. Pneumatic gate valve; 15. Drain point; 16. Cooling water inlet pipe; 17. Cooling water outlet pipe; 18. Gate valve; 19. Auxiliary steam pipe; 20. Drain point; 21. Exhaust valve; 22. Vacuum flow sight glass; 23. Vacuum gate valve; 24. Automatic vacuum drain valve. Detailed Implementation

[0022] The following is in conjunction with the appendix Figure 1 The present invention will be described in further detail below.

[0023] This utility model discloses a steam jet vacuum system for a power plant condenser. (Refer to...) Figure 1 The steam jet vacuum system of the power plant condenser includes a condenser 1, a water ring vacuum pump 2, a steam ejector 3, a steam pressure stabilizing tank 4, and a combined steam condenser 5.

[0024] Reference Figure 1The condenser 1 is connected to two water ring vacuum pumps 2 via a pipeline. This pipeline is equipped with a vacuum butterfly valve 6, a pneumatic vacuum butterfly valve 7, and a check valve 8. The steam ejectors 3 are arranged in three stages connected in series. The first stage has two steam ejectors 3, the second stage has one steam ejector 3, and the third stage has one steam ejector 3. A branch line is provided on the vacuum pipeline between the condenser 1 and the water ring vacuum pumps 2, connecting the input ends of the two first-stage steam ejectors 3 in parallel. This branch line is equipped with a pneumatic vacuum butterfly valve 7 and a butterfly valve 9. One steam ejector 3 is used under normal operating conditions, while the other steam ejector 3 is used as an auxiliary device during cylinder cut-off conditions.

[0025] Reference Figure 1 The input end of the steam pressure tank 4 is connected to the power steam. A shut-off valve 10, a mechanical pressure reducing valve 11, a pneumatic ball valve 12, a pneumatic regulating valve 13, and a pneumatic gate valve 14 are installed on this input pipeline, and a condensate drain point 15 is provided on this input pipeline. The output end of the steam pressure tank 4 is connected to the input end of the three-stage steam ejector 3, and a pneumatic gate valve 14 and a condensate drain point 15 are provided on this connecting pipeline.

[0026] Reference Figure 1 The combined steam condenser 5 is a three-stage condensation device. The output end of the first-stage steam ejector 3 is connected to the first-stage condensation device; the input end of the second-stage steam ejector 3 is connected to the output end of the first-stage condensation device, and the output end of the second-stage steam ejector 3 is connected to the input end of the second-stage condensation device; the input end of the third-stage steam ejector 3 is connected to the output end of the second-stage condensation device, and the output end of the third-stage steam ejector 3 is connected to the input end of the third-stage condensation device.

[0027] Reference Figure 1 The input end of the first-stage condenser is connected to a cooling water inlet pipe 16, and the output end of the third-stage condenser is connected to a cooling water outlet pipe 17. The cooling water is an open-loop circulating water system, drawing water from the outlet header of an open water pump. Gate valves 18 are installed on both the cooling water inlet pipe 16 and the cooling water outlet pipe 17. An auxiliary steam supply pipe 19 for supplying power steam to the second-stage condenser is also connected between the first-stage and second-stage condensers. Drain points 20 are installed on both the cooling water inlet pipe 16 and the auxiliary steam supply pipe 19. Exhaust valves 21 are also installed on both the first-stage and third-stage condensers.

[0028] Reference Figure 1 The outlet of the three-stage condensing unit of the combined steam condenser 5 is connected to the hot well of the condenser 1 by a U-shaped pipe. A vacuum flow sight glass 22, a vacuum gate valve 23 and a pneumatic vacuum butterfly valve 7 are installed on the U-shaped pipe. A vacuum automatic steam trap 24 is also installed on the U-shaped pipe connected to the third-stage condensing unit to balance the pressure difference between atmospheric pressure and condenser 1.

[0029] The implementation principle of the steam jet vacuum system for the power plant condenser in this embodiment is as follows: The system retains the original two water ring vacuum pumps 2 for pre-vacuuming of the system during the system startup phase. The first-stage steam jet 3 is directly connected to the vacuum pipe of the condenser 1. The non-condensable gas in the condenser 1 is injected and mixed with the motive steam before entering the first-stage condensing device for cooling. The second-stage steam jet 3 is connected to the first-stage condensing device and injects the non-condensable gas in it into the second-stage condensing device after mixing with the motive steam. Finally, the third-stage steam jet 3 injects the non-condensable gas in the second-stage condenser into the third-stage condenser, where it is fully cooled before being directly discharged into the atmosphere.

[0030] The first-stage steam ejector 3 consists of two steam ejectors 3. Under normal operating conditions, only one is used. When cylinder shut-off is required, both steam ejectors 3 are used simultaneously to compensate for insufficient extraction volume. Drainage from each stage of the condenser is recovered to the hot well of condenser 1 via a U-shaped pipe. The third-stage steam ejectors 3 are connected in series. Powered steam is jetted at supersonic speed through a powered nozzle to create a vacuum and extract non-condensable gases from condenser 1. This system requires no motor and consumes no plant power. To ensure sufficient powered steam under deep-conditioning conditions, the powered steam for this system is taken from cold reheat steam.

[0031] After the vacuum system upgrade, the original water ring vacuum pump 2 only operates during startup to establish a vacuum. Under normal operating conditions, it remains in standby mode, eliminating the risk of cavitation and equipment damage. Therefore, the original water ring vacuum pump 2 does not require disassembly and maintenance, effectively reducing maintenance frequency. Replacing the currently operating water ring vacuum pump 2 with a steam ejector vacuum system not only improves the unit's vacuum operation under high summer temperatures and eliminates the safety hazards caused by water ring vacuum pump 2 cavitation, but also reduces unit back pressure and turbine blow-off impact during winter cylinder shut-off. Furthermore, it offers significant energy-saving benefits.

[0032] The above are all preferred embodiments of this utility model, and are not intended to limit the scope of protection of this utility model. Therefore, all equivalent changes made to the structure, shape and principle of this utility model should be included within the scope of protection of this utility model.

Claims

1. A steam jet vacuum system for a power plant condenser, characterized in that: The system includes a condenser (1), a water ring vacuum pump (2), a multi-stage steam ejector (3), a steam pressure tank (4), and a combined steam condenser (5). The condenser (1) is connected to the water ring vacuum pump (2) and the first-stage steam ejector (3) through a pipeline. Power steam is introduced into the inlet of the multi-stage steam ejector (3) after passing through the steam pressure tank (4). The first-stage steam ejector (3) includes two steam ejectors (3) arranged in parallel. The combined steam condenser (5) includes a multi-stage condensing device corresponding to the number of multi-stage steam ejectors (3). The multi-stage steam ejectors (3) and the multi-stage condensing device are connected in series. The inlet of the first-stage condensing device is connected to a cooling water inlet pipe (16), and the outlet of the last-stage condensing device is connected to a cooling water outlet pipe (17). The multi-stage condensing device returns water to the hot well of the condenser (1) through a U-shaped pipe.

2. The power plant condenser steam injection vacuum system according to claim 1, characterized in that: The system includes a three-stage steam ejector (3) and a three-stage condenser. The outlet of the first-stage steam ejector (3) is connected to the inlet of the first-stage condenser. The inlet of the second-stage steam ejector (3) is connected to the outlet of the first-stage condenser. The outlet of the second-stage steam ejector (3) is connected to the inlet of the second-stage condenser. The inlet of the third-stage steam ejector (3) is connected to the outlet of the second-stage condenser. The outlet of the third-stage steam ejector (3) is connected to the inlet of the third-stage condenser.

3. The power plant condenser steam injection vacuum system according to claim 1, characterized in that: An auxiliary steam pipe (19) is connected between the first-stage condenser and the second-stage condenser for supplying power steam to the second-stage condenser.

4. The power plant condenser steam injection vacuum system according to claim 1, characterized in that: A shut-off valve (10), a mechanical pressure reducing valve (11), a pneumatic ball valve (12), and a pneumatic regulating valve (13) are installed on the pipeline that supplies power steam to the steam pressure tank (4).

5. The power plant condenser steam injection vacuum system according to claim 1, characterized in that: A vacuum gate valve (23), a vacuum flow sight glass (22), and a pneumatic vacuum butterfly valve (7) are installed on the U-shaped tube.

6. The power plant condenser steam injection vacuum system according to claim 5, characterized in that: A vacuum automatic steam trap (24) is also installed on the U-shaped tube connecting to the last stage of the condenser.

7. The power plant condenser steam injection vacuum system according to claim 3, characterized in that: A drain point (20) is provided on the auxiliary steam pipe (19) and the cooling water inlet pipe (16).

8. The power plant condenser steam injection vacuum system according to claim 1, characterized in that: The cooling water is an open-loop circulating water system, and water is drawn from the outlet header of the open-loop water pump.

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