Low-pressure shaft seal temperature reduction system

Abstract

The utility model provides a low-pressure shaft seal temperature reduction system. Comprising a high-pressure cylinder, a medium-pressure cylinder, a low-pressure cylinder and a gas supply pipeline, and the gas supply pipeline is used for conveying steam to the high-pressure cylinder, the medium-pressure cylinder and the low-pressure cylinder; the temperature reduction assembly comprises a water spraying temperature reduction unit, a temperature obtaining unit and a water supply pipeline, the water supply pipeline is used for conveying condensed water to the water spraying temperature reduction unit, and the water spraying temperature reduction unit is arranged on the air supply pipeline between the medium-pressure cylinder and the low-pressure cylinder; the temperature obtaining unit is used for obtaining the temperature of steam conveyed to the low-pressure cylinder, and when the temperature of the steam conveyed to the low-pressure cylinder is larger than a temperature threshold value, the temperature obtaining unit controls the water spraying and temperature reducing unit to spray water into the air supply pipeline so as to reduce the temperature of the steam conveyed to the low-pressure cylinder.

Description

Technical Field

[0001] The utility model belongs to the technical field of thermal power generation, and in particular relates to a low-pressure shaft seal temperature reduction system. Background Art

[0002] When the thermal power generating unit is started or running at low load, the steam source of the shaft seal steam system mainly comes from the auxiliary steam main pipe. The auxiliary steam enters the shaft seal pressure regulating component for pressure regulation, so that the auxiliary steam maintains its normal pressure and temperature under various working conditions. In addition, part of the shaft seal steam comes from the leakage of the high and medium pressure valve stems. With the increase of the unit load, the leakage of the high and medium pressure cylinder shaft seals and the valve stem leakage of the high and medium pressure cylinder steam inlet valves also increase accordingly, causing the shaft seal steam pressure to rise. The steam source of the shaft seal steam system is switched to the leakage of the high and medium pressure cylinder valve stems to achieve the self-sealing of the low-pressure shaft seal. Regardless of the steam supply method, the low-pressure shaft seal temperature is required. For example, the temperature of the low-pressure shaft seal main pipe of the third phase of our plant is 121~177℃. Too low or too high will cause the low-pressure cylinder shaft seal section rotor and the low-pressure shaft seal steam supply temperature to deviate too much, which may cause unit vibration. Utility Model Content

[0003] The utility model provides a low-pressure shaft seal temperature reduction system, which can improve the stability of the unit. It includes:

[0004] An air supply assembly, comprising a high-pressure cylinder, a medium-pressure cylinder, a low-pressure cylinder and an air supply pipeline, wherein the air supply pipeline is used to transport steam to the high-pressure cylinder, the medium-pressure cylinder and the low-pressure cylinder;

[0005] A cooling component includes a water spray cooling unit, a temperature acquisition unit and a water supply pipeline, wherein the water supply pipeline is used to transport condensed water to the water spray cooling unit, and the water spray cooling unit is arranged on the air supply pipeline between the intermediate pressure cylinder and the low pressure cylinder; the temperature acquisition unit is used to acquire the temperature of the steam delivered to the low pressure cylinder, and when the temperature of the steam delivered to the low pressure cylinder is greater than a temperature threshold, the temperature acquisition unit controls the water spray cooling unit to spray water into the air supply pipeline to reduce the temperature of the steam delivered to the low pressure cylinder.

[0006] Optionally, the water supply pipeline comprises:

[0007] A first water supply branch, one end of which is connected to the condensate delivery pipeline, and the other end of which is connected to the water spray cooling unit. A first shut-off valve, a second shut-off valve and a first regulating valve are provided on the first water supply branch, and the first regulating valve is provided between the first shut-off valve and the second shut-off valve.

[0008] Optionally, the water supply pipeline further includes:

[0009] A second water supply branch, one end of which is connected to the water spray cooling unit, and the other end of which is connected to the condensate delivery pipeline, and a third shut-off valve is arranged on the second water supply branch.

[0010] Optionally, the gas supply pipeline comprises:

[0011] The first air supply branch is used to obtain steam delivered by the auxiliary steam manifold and deliver the steam to the high-pressure cylinder, the medium-pressure cylinder and the low-pressure cylinder. The first air supply branch is provided with a first one-way valve.

[0012] Optionally, a fourth shut-off valve and a second regulating valve are further provided on the first gas supply branch, the second regulating valve is arranged at an end close to the gas outlet of the first gas supply branch, the first one-way valve is located at an end close to the gas inlet of the first gas supply branch, and the fourth shut-off valve is arranged between the second regulating valve and the first one-way valve.

[0013] Optionally, a fifth shut-off valve is further provided on the first gas supply branch, and the fifth shut-off valve is provided between the gas inlet end of the first gas supply branch and the first one-way valve.

[0014] Optionally, the gas supply pipeline further includes:

[0015] The second gas supply branch is used to transport steam to the high-pressure cylinder, the medium-pressure cylinder and the low-pressure cylinder. The second gas supply branch is provided with a second one-way valve and a sixth shut-off valve.

[0016] Optionally, a seventh shut-off valve is further provided on the second gas supply branch, and the seventh shut-off valve is arranged between the gas inlet of the second gas supply branch and the second one-way valve.

[0017] Optionally, the gas supply pipeline comprises:

[0018] The first gas transmission branch is provided with a third regulating valve, and the first gas transmission branch is used to transmit the steam in the gas supply pipeline to the condenser.

[0019] Optionally, the gas supply pipeline further includes:

[0020] The second gas transmission branch is provided with an eighth shut-off valve, and the second gas transmission branch is used to transmit the steam in the gas supply pipeline to the condenser.

[0021] The technical solution provided by the embodiments of the present disclosure has the following beneficial effects:

[0022] In an embodiment of the present disclosure, a low-pressure shaft seal cooling system is provided, which includes an air supply component and a cooling component, wherein the cooling component includes a water spray cooling unit, a temperature acquisition unit and a water supply pipeline. The temperature of the steam delivered to the low-pressure cylinder is acquired by the temperature acquisition unit. When the temperature is too high, the temperature acquisition unit controls the water spray cooling unit to deliver condensed water to reduce the temperature of the steam delivered to the low-pressure cylinder. When the temperature of the steam is low, the temperature acquisition unit will not control the water spray cooling unit to spray water into the air supply pipeline. The temperature of the steam in the water supply pipeline can be regulated by the water spray cooling unit and the temperature acquisition unit, so that the steam temperature is kept within a certain range to avoid vibration of the unit. The cooling water of this scheme uses the condensed water at the outlet of the No. 5 low-pressure heater. Compared with the outlet of the condensate pump, the temperature is higher, the pressure is lower, and the surface tension of the water is smaller. After being sprayed out through the nozzle of the cooler, the atomization effect is better, the contact area with the shaft seal steam is increased, and the possibility of water accumulation caused by local excessively low temperature is avoided, thereby ensuring the effect of water spray cooling. In addition, the high-temperature spray water flashes after being sprayed out, and the vaporization time is short, which shortens the liquid existence time of water and is beneficial to reducing the steam-water two-phase vibration in the pipeline. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the technical solutions in the present invention or the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0024] Figure 1 A schematic structural diagram of a low-pressure shaft seal temperature reduction system provided in an embodiment of the present disclosure.

[0025] The reference numerals are as follows:

[0026] 1: air supply assembly; 11: high pressure cylinder; 12: medium pressure cylinder; 13: low pressure cylinder; 14: air supply pipeline; 141: first air supply branch; 1411: first one-way valve; 1412: fourth shut-off valve; 1413: second regulating valve; 1414: fifth shut-off valve; 142: second air supply branch; 1421: second one-way valve; 1422: sixth shut-off valve; 1423: seventh shut-off valve; 143: first air transmission branch; 1431: third regulating valve; 144: second air transmission branch; 1441: eighth shut-off valve;

[0027] 2: cooling component; 21: water spray cooling unit; 22: temperature acquisition unit; 23: water supply pipeline; 231: first water supply branch; 2311: first shut-off valve; 2312: first regulating valve; 2313: second shut-off valve; 232: second water supply branch; 2321: third shut-off valve; 24: condensate water delivery pipeline. DETAILED DESCRIPTION

[0028] In order to make the purpose, technical solution and advantages of the utility model clearer, the technical solution of the utility model will be clearly and completely described below in conjunction with the drawings in the utility model. Obviously, the described embodiments are part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0029] Figure 1 This is a schematic diagram of the structure of a low-pressure shaft seal temperature reduction system provided by an embodiment of the present disclosure. Figure 1 The system comprises:

[0030] The gas supply assembly 1 comprises a high-pressure cylinder 11, a medium-pressure cylinder 12, a low-pressure cylinder 13 and a gas supply pipeline 14, wherein the gas supply pipeline 14 is used to transport steam to the high-pressure cylinder 11, the medium-pressure cylinder 12 and the low-pressure cylinder 13;

[0031] The cooling component 2 includes a water spray cooling unit 21, a temperature acquisition unit 22 and a water supply pipeline 23. The water supply pipeline 23 is used to transport condensed water to the water spray cooling unit 21. The water spray cooling unit 21 is arranged on the air supply pipeline between the intermediate pressure cylinder 12 and the low pressure cylinder 13; the temperature acquisition unit 22 is used to obtain the temperature of the steam delivered to the low pressure cylinder 13. When the temperature of the steam delivered to the low pressure cylinder 13 is greater than the temperature threshold, the temperature acquisition unit 22 controls the water spray cooling unit 21 to spray water into the air supply pipeline 14 to reduce the temperature of the steam delivered to the low pressure cylinder 13.

[0032] In an embodiment of the present disclosure, a low-pressure shaft seal cooling system is provided, which includes an air supply component and a cooling component, wherein the cooling component includes a water spray cooling unit, a temperature acquisition unit and a water supply pipeline. The temperature of the steam delivered to the low-pressure cylinder is acquired by the temperature acquisition unit. When the temperature is too high, the temperature acquisition unit controls the water spray cooling unit to deliver condensed water to reduce the temperature of the steam delivered to the low-pressure cylinder. When the temperature of the steam is low, the temperature acquisition unit will not control the water spray cooling unit to spray water into the air supply pipeline. The temperature of the steam in the water supply pipeline can be regulated by the water spray cooling unit and the temperature acquisition unit, so that the steam temperature is kept within a certain range to avoid vibration of the unit. The cooling water of this scheme uses the condensed water at the outlet of the No. 5 low-pressure heater. Compared with the outlet of the condensate pump, the temperature is higher, the pressure is lower, and the surface tension of the water is smaller. After being sprayed out through the nozzle of the cooler, the atomization effect is better, the contact area with the shaft seal steam is increased, and the possibility of water accumulation caused by local excessively low temperature is avoided, thereby ensuring the cooling effect of the water spray. In addition, the higher temperature spray water flashes after being sprayed out, and the vaporization time is short, which shortens the liquid existence time of water and is beneficial to reducing the steam-water two-phase vibration in the pipeline.

[0033] In the embodiment of the present disclosure, the gas supply pipeline 14 includes:

[0034] The first air supply branch 141 is used to obtain steam delivered by the auxiliary steam manifold and deliver the steam to the high-pressure cylinder 11 , the medium-pressure cylinder 12 and the low-pressure cylinder 13 . The first air supply branch 141 is provided with a first one-way valve 1411 .

[0035] In the embodiment of the present disclosure, the first one-way valve is provided to avoid steam backflow, which is beneficial to the stability of the system.

[0036] In the embodiment of the present disclosure, a fourth shut-off valve 1412 and a second regulating valve 1413 are further provided on the first gas supply branch 141, the second regulating valve 1413 is arranged at an end close to the gas outlet of the first gas supply branch 141, the first one-way valve 1411 is located at an end close to the gas inlet of the first gas supply branch 141, and the fourth shut-off valve 1412 is arranged between the second regulating valve 1413 and the first one-way valve 1411.

[0037] In the embodiment of the present disclosure, the second regulating valve is provided to facilitate controlling the delivery of steam, and the fourth shut-off valve is provided to facilitate closing the first gas supply branch when there is no need to deliver steam.

[0038] It is worth mentioning that when the load of the thermal power generating unit is above 30%, the gas supply pipeline will be closed and no gas supply is required at this time. However, the thermal power generating unit operates at a load of more than 30% for a long time. Therefore, setting a shut-off valve is also beneficial to further avoid damage to the regulating valve.

[0039] In the embodiment of the present disclosure, a fifth shut-off valve 1414 is further provided on the first air supply branch 141 , and the fifth shut-off valve 1414 is provided between the air inlet end of the first air supply branch 141 and the first one-way valve 1411 .

[0040] In the embodiment of the present disclosure, providing a fifth shut-off valve is beneficial to further ensure the closedness of the first gas supply branch.

[0041] In the embodiment of the present disclosure, the gas supply pipeline 14 further includes:

[0042] The second air supply branch 142 is used to transport steam to the high-pressure cylinder 11, the medium-pressure cylinder 12 and the low-pressure cylinder 13. The second air supply branch 142 is provided with a second one-way valve 1421 and a sixth shut-off valve 1422.

[0043] In the disclosed embodiment, the second air supply branch is a backup pipeline, and providing the second air supply branch is beneficial to improving the stability of the air supply pipeline.

[0044] In the embodiment of the present disclosure, a seventh shut-off valve 1423 is further provided on the second gas supply branch 142 , and the seventh shut-off valve 1423 is arranged between the gas inlet of the second gas supply branch 142 and the second one-way valve 1421 .

[0045] In the embodiment of the present disclosure, providing a seventh shut-off valve can further ensure the sealing performance of the second gas supply branch.

[0046] In the embodiment of the present disclosure, the gas supply pipeline 14 includes:

[0047] The first gas transmission branch 143 is provided with a third regulating valve 1431 , and the first gas transmission branch 143 is used to transmit the steam in the gas supply pipeline 14 to the condenser and the No. 9 low-pressure heater.

[0048] In the disclosed embodiment, after the shaft seal temperature is lowered, it can match the steam inlet temperature of the No. 9 low-pressure heater. As the load continues to rise, the pressure of the shaft seal continues to increase, and the first gas transmission branch is opened to allow excess steam leakage from the steam seal to flow to the No. 9 low-pressure heater, heating the condensate and improving the efficiency of the unit.

[0049] In the embodiment of the present disclosure, the gas supply pipeline further includes:

[0050] The second gas transmission branch is provided with an eighth shut-off valve, and the second gas transmission branch is used to transmit the steam in the gas supply pipeline to the condenser.

[0051] In the disclosed embodiment, the second gas transmission branch is used as a backup branch to increase the adjustment margin. When the shaft seal leakage of the high and medium pressure cylinders is large at high load, and the leakage is so large that the first gas transmission branch is not enough to discharge it, the second gas transmission branch is opened to ensure the discharge efficiency of the overflow steam.

[0052] In the embodiment of the present disclosure, the water supply pipeline 23 includes:

[0053] The first water supply branch 231, one end of the first water supply branch 231 is connected to the condensate delivery pipeline 24, and the other end is connected to the water spray cooling unit 21, the condensate delivery pipeline 24 is used to transport the condensate at the outlet of No. 5 low-pressure heater, the first water supply branch 231 is provided with a first shut-off valve 2311, a second shut-off valve 2313 and a first regulating valve 2312, and the first regulating valve 2312 is arranged between the first shut-off valve 2311 and the second shut-off valve 2312.

[0054] In the disclosed embodiment, the condensate at the outlet of the No. 5 low-pressure heater is used as the water source. The condensate at the outlet of the No. 5 low-pressure heater has a higher temperature, a lower pressure, and a smaller surface tension. After being sprayed out through the nozzle of the water spray cooling unit, the atomization effect is better, and the contact area with the shaft seal steam is increased, thereby avoiding the possibility of water accumulation due to local excessively low temperature, and ensuring the water spray cooling effect. In addition, the high-temperature spray water flashes after being sprayed out, and the vaporization time is short, which shortens the liquid existence time of the water, and is beneficial to reducing the steam-water two-phase vibration in the pipeline. A regulating valve is used on the first water supply branch, and shut-off valves are set at both ends of the regulating valve. When there is no need to cool the steam in the gas supply pipeline, the regulating valve on the first water supply branch is in a closed state. Since the steam in the gas supply pipeline does not need to be cooled most of the time, the regulating valve is in a closed state for some of the time, which makes the regulating valve more easily damaged. Shut-off valves are set before and after the regulating valve. The shut-off valve can cut off the water flow, thereby ensuring the water flow cutting effect of the first branch. Moreover, when the regulating valve is damaged or needs to be replaced, the shut-off valves before and after the regulating valve can be used to cut off the water flow and then the regulating valve can be repaired or replaced.

[0055] In the embodiment of the present disclosure, the water supply pipeline 23 further includes:

[0056] The second water supply branch 232 has one end connected to the water spray cooling unit 21 and the other end connected to the condensate delivery pipeline 24 . The second water supply branch 232 is provided with a third shut-off valve 2321 .

[0057] In the disclosed embodiment, a second water supply branch is provided, and a third shut-off valve is provided on the second water supply branch. When the water supply pipeline is in operation, the valve on the first water supply branch is fully opened, and the valve on the second branch is closed. When the regulating valve on the first water supply branch fails, the shut-off valve on the first water supply branch can be fully closed, and the shut-off valve on the second water supply branch is opened to continue to transport condensate through the second arch water supply branch, thereby ensuring that the temperature of the low-pressure shaft seal mother pipe is normal and improving stability.

[0058] In the embodiment of the present disclosure, the water spray cooling unit 21 is a water spray cooler, and the temperature acquisition unit 22 may be a temperature sensor.

[0059] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the utility model, rather than to limit it. Although the utility model has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the utility model.

Claims

1. A low-pressure shaft seal temperature reduction system, characterized in that: include: An air supply assembly, comprising a high-pressure cylinder, a medium-pressure cylinder, a low-pressure cylinder and an air supply pipeline, wherein the air supply pipeline is used to transport steam to the high-pressure cylinder, the medium-pressure cylinder and the low-pressure cylinder; A cooling component includes a water spray cooling unit, a temperature acquisition unit and a water supply pipeline, wherein the water supply pipeline is used to transport condensed water to the water spray cooling unit, and the water spray cooling unit is arranged on the air supply pipeline between the intermediate pressure cylinder and the low pressure cylinder; the temperature acquisition unit is used to acquire the temperature of the steam delivered to the low pressure cylinder, and when the temperature of the steam delivered to the low pressure cylinder is greater than a temperature threshold, the temperature acquisition unit controls the water spray cooling unit to spray water into the air supply pipeline to reduce the temperature of the steam delivered to the low pressure cylinder.

2. The low-pressure shaft seal temperature reduction system according to claim 1, characterized in that: The water supply pipeline comprises: The first water supply branch, one end of the first water supply branch is connected to the condensate delivery pipeline, and the other end is connected to the water spray cooling unit, the condensate delivery pipeline is used to transport the condensate at the outlet of No. 5 low-pressure heater, the first water supply branch is provided with a first shut-off valve, a second shut-off valve and a first regulating valve, the first regulating valve is arranged between the first shut-off valve and the second shut-off valve.

3. The low-pressure shaft seal temperature reduction system according to claim 2, characterized in that: The water supply pipeline also includes: A second water supply branch, one end of which is connected to the water spray cooling unit, and the other end of which is connected to the condensate delivery pipeline, and a third shut-off valve is arranged on the second water supply branch.

4. The low-pressure shaft seal temperature reduction system according to any one of claims 1 to 3, characterized in that: The gas supply pipeline comprises: The first air supply branch is used to obtain steam delivered by the auxiliary steam manifold and deliver the steam to the high-pressure cylinder, the medium-pressure cylinder and the low-pressure cylinder. The first air supply branch is provided with a first one-way valve.

5. The low-pressure shaft seal temperature reduction system according to claim 4, characterized in that: The first gas supply branch is also provided with a fourth shut-off valve and a second regulating valve, the second regulating valve is arranged at an end close to the gas outlet of the first gas supply branch, the first one-way valve is located at an end close to the gas inlet of the first gas supply branch, and the fourth shut-off valve is arranged between the second regulating valve and the first one-way valve.

6. The low-pressure shaft seal temperature reduction system according to claim 5, characterized in that: The first air supply branch is also provided with a fifth shut-off valve, and the fifth shut-off valve is arranged between the air inlet end of the first air supply branch and the first one-way valve.

7. The low-pressure shaft seal temperature reduction system according to any one of claims 1 to 3, characterized in that: The gas supply pipeline also includes: The second gas supply branch is used to transport steam to the high-pressure cylinder, the medium-pressure cylinder and the low-pressure cylinder. The second gas supply branch is provided with a second one-way valve and a sixth shut-off valve.

8. The low-pressure shaft seal temperature reduction system according to claim 7, characterized in that: The second gas supply branch is also provided with a seventh shut-off valve, and the seventh shut-off valve is arranged between the gas inlet of the second gas supply branch and the second one-way valve.

9. The low-pressure shaft seal temperature reduction system according to any one of claims 1 to 3, characterized in that: The gas supply pipeline comprises: The first gas transmission branch is provided with a third regulating valve, and the first gas transmission branch is used to transmit the steam in the gas supply pipeline to the condenser.

10. The low-pressure shaft seal temperature reduction system according to claim 9, characterized in that: The gas supply pipeline also includes: The second gas transmission branch is provided with an eighth shut-off valve, and the second gas transmission branch is used to transmit the steam in the gas supply pipeline to the condenser.

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