Steam turbine shaft seal heater primary and secondary condensate recovery system
By using a water seal straight barrel in the turbine shaft seal heater and combining a flowmeter and water pump adjustment system, the problem of serpentine water seal not adaptable to the negative pressure difference is solved, flexible adjustment of the water seal height and adaptability of the negative pressure difference is achieved, avoiding the problems of poor return water and air leakage, and reducing maintenance and electricity costs.
Patent Information
- Application Number
- CN202420920772.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-04-29
- Publication Date
- 2025-04-08
- Estimated Expiration
- 2034-04-29
AI Technical Summary
In existing turbine shaft seal heaters, the snake-shaped water seal cannot adapt to the negative pressure difference between the condenser and the shaft seal heater, resulting in poor return water or vacuum leakage, and increasing the trap or negative pressure air can increase maintenance frequency and electricity consumption.
A water sealing straight cylinder is used instead of a serpentine water seal, and the water flow velocity is detected through a flowmeter, and the water seal height and water pressure are adjusted by a water pump to adapt to the negative pressure difference to avoid poor return water or air leakage.
It realizes flexible adjustment of the water seal height, and the negative pressure difference between the adaptive condenser and the shaft seal heater avoids the problems of poor return water and air leakage, while reducing equipment maintenance and power consumption.
Smart Images
Figure CN222731603U_ABST
Abstract
Description
Technical Field
[0001] The present application relates to the technical field of steam turbine drainage, and in particular to a primary and secondary condensate recovery system for a steam turbine shaft seal heater. Background Art
[0002] The shaft seal heater is an essential auxiliary equipment in the operation of the steam turbine. It is used to recover the steam leakage from the front and rear steam seals of the steam turbine, heat the steam condensate of the steam turbine, and increase the condensate temperature. The shaft seal heater is divided into two stages. The mixture of the front and rear steam seal leakage enters the first stage, and the new steam generated by the shaft seal heater enters the other stage. The mixture of the front and rear steam seal leakage and steam heat the condensate of the steam turbine, condensing the steam into water, forming a two-stage drain and sending it to the condenser.
[0003] The existing shaft seal heater is usually placed on a 3-meter platform. After the steam condenses, it is recovered to the condenser using a serpentine water seal. Since the condenser is under negative pressure during operation, the serpentine water seal must overcome the negative pressure during operation of the condenser to recover the primary condensate and secondary condensate of the shaft seal heater. During operation, the negative pressure difference between the condenser and the shaft seal heater is in a changing state, and after the serpentine water seal is filled with water, the water level remains basically unchanged, which is not easy to adjust; therefore, the serpentine water seal will have poor water return when the flow resistance is large, and will leak vacuum when the water return resistance is small.
[0004] In order to overcome the above-mentioned defects of the serpentine water seal, the existing shaft seal heater usually adds a steam trap on the pipe feeding into the condenser, or adds a negative pressure fan at the exhaust port of the shaft seal heater; since the steam trap must be closely monitored during operation and leakage is prone to occur, adding a steam trap will increase the maintenance and overhaul frequency of power plant equipment, and adding a negative pressure fan will increase the power consumption of the power plant. At the same time, the negative pressure fan equipment also needs regular maintenance and overhaul. Summary of the invention
[0005] The purpose of the utility model is to provide a first and second stage condensate recovery system for a steam turbine shaft seal heater, which can adjust the water seal height during operation, overcome the defect that the serpentine water seal cannot adapt to the negative pressure difference between the condenser and the shaft seal heater, and at the same time does not require the addition of large electronic equipment and does not require frequent inspection and maintenance.
[0006] The technical scheme adopted by the utility model is: a primary and secondary condensate recovery system of a steam turbine shaft seal heater, comprising a shaft seal heater, a water seal cylinder, a condenser and a regulating tank, wherein the shaft seal heater has a two-stage drain port, the two-stage drain port of the shaft seal heater, the condenser and the regulating tank are connected to the water seal cylinder through pipelines, the bottom surfaces of the shaft seal heater and the condenser are higher than the top surface of the water seal cylinder, valves are arranged on the pipelines connecting the two-stage drain port of the shaft seal heater, the condenser and the regulating tank with the water seal cylinder, a flow meter is also arranged on the pipeline connecting the condenser with the water seal cylinder, and a water pump is also arranged on the pipeline connecting the regulating tank with the water seal cylinder.
[0007] Furthermore, the liquid level in the water-sealed straight cylinder is not less than 7m.
[0008] The beneficial effects of the utility model are as follows: the utility model uses a water seal straight cylinder to replace the serpentine water seal. Compared with the serpentine water seal, the water seal straight cylinder can more simply adjust the water seal height, so that the water seal straight cylinder can adapt to the negative pressure difference between the condenser and the shaft seal heater; the utility model controls the operation of the water pump according to the detection result of the flow meter. When the flow rate of the flow meter is too large, the water in the regulating tank is pumped into the water seal straight cylinder, the water seal height is increased to increase the water pressure and avoid air leakage; when the flow rate of the flow meter is too small, the water in the water seal straight cylinder is pumped into the regulating tank, the water seal height is lowered to reduce the water pressure and avoid poor return water; since the utility model does not add large electronic equipment, it will not increase power consumption, and does not require frequent inspection and maintenance. It only needs to be regularly inspected and maintained together with the turbine shaft seal system. BRIEF DESCRIPTION OF THE DRAWINGS
[0009] In order to more clearly illustrate the technical solutions in the embodiments of the present utility model, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.
[0010] Figure 1 It is a structural schematic diagram of an embodiment of the utility model.
[0011] Explanation of the accompanying drawings: 1-shaft seal heater, 2-water seal cylinder, 3-condenser, 4-regulating tank, 5-primary drain outlet, 6-secondary drain outlet, 7-valve, 8-flow meter, 9-water pump. DETAILED DESCRIPTION
[0012] In order to more clearly understand the above-mentioned purpose, features and advantages of the utility model, the utility model is further described in detail below in conjunction with the accompanying drawings and specific embodiments. In the following description, many specific details are set forth to facilitate a full understanding of the utility model, but the utility model can also be implemented in other ways different from those described herein, and therefore, the utility model is not limited to the limitations of the specific embodiments disclosed below.
[0013] Unless otherwise defined, the technical or scientific terms used herein shall have the usual meanings understood by persons of ordinary skill in the field described in this application. The words "first", "second" and similar terms used in this patent application specification and claims do not indicate any order, quantity or importance, but are only used to distinguish different components. Similarly, words such as "one" or "an" do not indicate a quantity limitation, but indicate the existence of at least one. Words such as "connected" or "connected" are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. "Up", "down", "left", "right" and the like are only used to indicate relative positional relationships. When the absolute position of the object being described changes, the relative positional relationship also changes accordingly.
[0014] like Figure 1 As shown, a one-stage and two-stage condensate recovery system of a steam turbine shaft seal heater comprises a shaft seal heater 1, a water seal cylinder 2, a condenser 3 and a regulating tank 4. The shaft seal heater 1 has a two-stage drain port, the first-stage drain port 5 is used to recover the condensate generated by the steam leakage mixture of the front and rear steam seals of the steam turbine in the shaft seal heater 1, and the second-stage drain port 6 is used to recover the condensate generated by the steam generated by the shaft seal heater 1 during operation. The two-stage drain port of the shaft seal heater 1, the condenser 3 and the regulating tank 4 are all connected to the water seal cylinder 2 through pipelines, and the bottom surfaces of the shaft seal heater 1 and the condenser 3 are higher than the top surface of the water seal cylinder 2. The two-stage drain port of the shaft seal heater 1, the condenser 3 and the regulating tank 4 are all provided with valves 7 on the pipelines connecting the water seal cylinder 2. It should be noted that the valve 7 is a basic valve equipped for the water seal pipeline, which is used to open or close the corresponding pipeline. It is not the same component as the steam trap mentioned in the background technology. The steam trap is a component added on the basis of the valve 7 provided on the pipeline. A flow meter 8 is also provided on the pipeline connecting the condenser 3 and the water seal cylinder 2. The flow meter 8 is used to detect the water flow rate flowing into the condenser 3 as a basis for adjusting the water seal height in the water seal cylinder 2. A water pump 9 is also provided on the pipeline connecting the regulating tank 4 and the water seal cylinder 2 to realize the transfer of water between the regulating tank 4 and the water seal cylinder 2.
[0015] The working principle of the utility model is: after the water seal cylinder 2 is set, the shaft seal heater 1 and the condenser 3 are set on a plane not lower than the water seal cylinder 2. According to the production experience of the production site, the liquid level in the water seal cylinder 2 needs to be no less than 7m, so the height of the water seal cylinder 2 needs to be no less than 7m, and the shaft seal heater 1 and the condenser 3 need to be set on a platform not lower than 7m. The valve 7, the flow meter 8 and the water pump 9 are connected to the control system of the plant, such as the CPU control system or the PLC control system, for automatic control. During the operation of the shaft seal heater 1 and the condenser 3, the velocity of the water flowing into the condenser 3 is detected by the flow meter 8. If the velocity detected by the flow meter 8 is greater than the normal velocity, it means that the current water pressure in the water seal cylinder 2 cannot overcome the negative pressure in the condenser 3. The condensed water flows into the condenser 3 rapidly under the negative pressure in the condenser 3, and at the same time, the air is brought into the condenser 3 to destroy the negative pressure environment and cause air leakage. At this time, the control system will control the water pump 9 to work, and the water in the regulating tank 4 is pumped into the water seal cylinder 2, and the water seal height is increased to increase the water pressure to avoid air leakage. If the velocity detected by the flow meter 8 is less than the normal velocity, it means that the current water pressure in the water seal cylinder 2 is too high, and the negative pressure in the condenser 3 cannot overcome the water pressure in the water seal cylinder 2, and the condensed water cannot be sucked into the condenser 3, resulting in poor water return. At this time, the control system will control the water pump 9 to work, and the water in the water seal cylinder 2 is pumped into the regulating tank 4, and the water seal height is reduced to reduce the water pressure to avoid poor water return.
[0016] The embodiment of the utility model uses a water seal straight cylinder 2 to replace the serpentine water seal. Compared with the serpentine water seal, the water seal straight cylinder 2 can more easily adjust the water seal height, so that the water seal straight cylinder 2 can adapt to the negative pressure difference between the condenser 3 and the shaft seal heater 1 to maintain the normal operation of the condenser 3 and the shaft seal heater 1; since the embodiment of the utility model does not add large-scale electronic equipment, the investment cost is low, the power consumption will not be greatly increased, and frequent inspection and maintenance are not required. It only needs to be regularly inspected and maintained together with the turbine shaft seal system.
[0017] The above description is only the preferred embodiment of the utility model, and is not intended to limit the utility model. For those skilled in the art, the utility model can have various modifications and changes. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the utility model shall be included in the protection scope of the utility model.
Claims
1. A primary and secondary condensate recovery system for a steam turbine shaft seal heater, characterized in that: It includes a shaft seal heater, a water seal cylinder, a condenser and an adjusting tank. The shaft seal heater has a two-stage drain port. The two-stage drain port of the shaft seal heater, the condenser and the adjusting tank are connected to the water seal cylinder through pipelines. The bottom surfaces of the shaft seal heater and the condenser are higher than the top surface of the water seal cylinder. Valves are arranged on the pipelines connecting the two-stage drain port of the shaft seal heater, the condenser and the adjusting tank with the water seal cylinder. A flow meter is also arranged on the pipeline connecting the condenser with the water seal cylinder. A water pump is also arranged on the pipeline connecting the adjusting tank with the water seal cylinder.
2. A steam turbine shaft seal heater primary and secondary condensate recovery system according to claim 1, characterized in that: The liquid level in the water-sealed straight cylinder is not less than 7m.