External cooling system for drainage pump of air heater of coal-fired power plant
By designing an external cooling system in the air heater drain pump of coal-fired power plant, using the combination of cooling pipe and injection pipe, the leakage problem caused by temperature changes of mechanical seals is solved, and the efficient and stable operation and low maintenance of the drain pump is achieved. cost.
Patent Information
- Application Number
- CN202421131817.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-05-22
- Publication Date
- 2024-12-24
- Estimated Expiration
- 2034-05-22
AI Technical Summary
The mechanical seal of the air heater drain pump in the coal-fired power plant air heater has different expansion amounts due to different working fluid temperatures, which can easily get stuck or wear, resulting in increased leakage, reducing the reliability and recovery rate of the drain pump, and affecting the unit's coal consumption and power generation cost.
An external cooling system is designed to conduct the working fluid at the outlet of the drain pump to the cooler through the cooling pipe, and cool it with desalinate or industrial water, control the mechanical sealing temperature in a constant range, and combine the setting of the valve and the jet pipe. Ensure rapid cooling and stable sealing of the working fluid.
It effectively improves the service life and operating stability of mechanical seals, forms a zero-leakage and high-efficiency hydrophobic pump system, reduces maintenance costs, and improves the recovery rate of working fluids, and reduces cavitation risks.
Smart Images
Figure CN222228979U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the field of drain pump equipment, in particular to an external cooling system for a drain pump of a heater in a coal-fired power plant. Background Art
[0002] Steam-heated air heaters are currently a common system installed in large power plant boilers. Its main principle is to use plant steam to heat the supply air to increase the air temperature and prevent the cold end wall temperature of the air preheater from being lower than the flue gas dew point temperature, causing acid corrosion on the heating surface.
[0003] At present, the effect of the heaters in most power plants is not good, and problems such as poor drainage often occur. The heater drain recovery system is large and complex, and its operating conditions are greatly affected by the system configuration and working fluid parameters. When the working fluid is in a saturated state under normal working conditions, the heater drain pump is very prone to cavitation. The mechanical seal of the drain pump is stuck with the pump shaft or wears due to the different working fluid temperatures under different working conditions, the different temperatures of the mechanical seal and the pump shaft, and the different expansion amounts. After the mechanical seal wears, the leakage of the working fluid increases, resulting in low reliability of the heater drain pump and low heater drain recovery rate, which directly affects the coal consumption of the unit and increases the cost of power generation. Utility Model Content
[0004] The utility model is intended to provide an external cooling system for a heater drain pump of a coal-fired power plant, so as to solve the problem that the temperature difference between the mechanical seal and the pump shaft causes different expansion amounts, resulting in the mechanical seal and the pump shaft being stuck, or the mechanical seal being worn, and the working fluid leakage increasing after the mechanical seal is worn, resulting in low reliability of the heater drain pump and low heater drain recovery rate, which directly affects the coal consumption of the unit and increases the power generation cost.
[0005] The external cooling system of the drain pump of the heater of the coal-fired power plant in this scheme includes a cooling pipe for conducting working medium drawn out from the outlet of the drain pump, the cooling pipe is connected to a cooler, and the cooler is connected to a delivery pipeline for conveying desalted water or industrial water for cooling;
[0006] One end of the cooling pipe leading out from the cooler is connected to the mechanical seal dynamic ring of the drain pump, so that the cooled working medium enters the first-stage impeller inlet of the drain pump after passing through the gap and the dynamic and static sealing surfaces.
[0007] The beneficial effects of this program are:
[0008] By using an external heat exchange cooler to lower the working fluid temperature and keep the temperature relatively constant, the temperature parameters of the mechanical seal system of the drain pump are controlled within a relatively constant and reasonable range, which increases the service life and operating stability of the mechanical seal of the drain pump, and forms a zero-leakage, high-efficiency heater drain pump system. This improves the reliability of equipment operation, reduces maintenance costs, and ensures that all the heat loss of the working fluid is recovered by the cooler.
[0009] Furthermore, the heat exchange area and cooling water consumption of the cooler increase as the capacity of the drain pump increases.
[0010] The beneficial effect is that the setting of the cooler can quickly cool the cooling water and ensure the processing efficiency.
[0011] Furthermore, a first valve is connected to one end of the cooling pipe leading out of the cooler, and a second valve is connected to the cooling pipe at the outlet end of the drain pump.
[0012] The beneficial effect is that the flow direction of the working medium can be controlled by setting the two valves, so that the working medium can be cooled when needed.
[0013] Furthermore, the cooling pipe is introduced from the radial direction of the drain pump.
[0014] The beneficial effects are: reducing the inlet temperature and reducing the problem of cavitation.
[0015] Furthermore, the water inlet and outlet of the delivery pipeline are respectively connected with control valves.
[0016] The beneficial effect is that the control valve on the pipeline for conveying cooling water can facilitate the applicable control of the cooling water.
[0017] Furthermore, the mechanical seal is a containerized bellows mechanical seal.
[0018] Furthermore, the delivery pipeline is fixedly provided with a spray pipe extending to a preset length on the water outlet end of the inner wall of the cooler, and the spray pipe includes an inclined section and a soft section, and the inclined section is inclined toward the port where the cooling pipe enters the cooler.
[0019] The beneficial effect is: by spraying the industrial water or desalted water transported into the cooler toward the entrance of the cooling pipe through the injection pipe, and then randomly shaking the soft section under the action of water pressure to stir the industrial water or desalted water in the cooler, the working fluid can quickly contact the industrial water or desalted water after being transported into the cooler, thereby improving the heat exchange efficiency.
[0020] Furthermore, the angle between the inclined section and the horizontal plane is 35°, and the length of the soft section is one fifth of the length of the inclined section.
[0021] The beneficial effect is that the angle of the inclined section can be aligned with the entry end of the cooling pipe in the cooler in a general direction, and the length of the soft section is smaller than the inclined section, which can improve the multi-directionality of the soft section's random shaking to scan the cooling pipe for heat exchange. BRIEF DESCRIPTION OF THE DRAWINGS
[0022] Figure 1 It is a schematic diagram of the first embodiment of the utility model of the external cooling system of the water drain pump of the heater of the coal-fired power plant;
[0023] Figure 2 It is a longitudinal cross-sectional view of the mechanical seal in the first embodiment of the external cooling system of the heater drain pump of a coal-fired power plant of the utility model;
[0024] Figure 3 It is a schematic diagram of a second embodiment of the utility model of an external cooling system for a heater drain pump in a coal-fired power plant. DETAILED DESCRIPTION
[0025] The following is further explained in detail through specific implementation methods.
[0026] The reference numerals in the drawings of the specification include: a cooler 21 , a control valve 22 , a first valve 23 , a second valve 24 , a delivery pipeline 25 , a cooling pipe 26 , an inclined section 27 , and a soft section 28 .
[0027] Embodiment 1
[0028] Coal-fired power plant heater drain pump external cooling system, such as Figure 1 As shown, it includes a cooling pipe 26 for conducting working medium from the outlet of the drain pump, the drain pump is located at the output end of the drain tank, the cooling pipe 26 is connected to a cooler 21, and the cooler 21 is connected to a delivery pipeline 25 for conveying demineralized water or industrial water for cooling. The water inlet and outlet ends of the delivery pipeline 25 are respectively connected to control valves 22.
[0029] One end of the cooling pipe 26 leading out from the cooler 21 is connected to the mechanical seal dynamic ring of the drain pump, so that the cooled working fluid passes through the gap and the dynamic and static sealing surfaces and enters the first-stage impeller inlet of the drain pump. The heat exchange area and cooling water consumption of the cooler 21 increase as the capacity of the drain pump increases, and the specific heat exchange area is set according to actual needs.
[0030] The first valve 23 is connected to one end of the cooling pipe 26 leading out of the cooler 21, and the second valve 24 is connected to the cooling pipe 26 at the outlet end of the drain pump. The arrangement of each valve can facilitate control. The cooling pipe 26 is introduced from the radial direction of the drain pump, that is, the radial introduction is at the inlet of the pump, and the water flows in the direction of the impeller inlet of the pump, so as to reduce the inlet temperature and reduce cavitation.
[0031] like Figure 2 As shown, the mechanical seal is a container-type bellows mechanical seal, in which the meanings of the accompanying drawings are respectively: stationary ring seat 1, limit plate 2, locking ring 3, sleeve 4, stationary ring 5, dynamic ring 6, first O-ring 7, spring washer 8, push ring 9, fixing bolt 10, second O-ring 11, spring 12. Its specific structural connection is not the focus of protection of this scheme and will not be repeated here.
[0032] The specific implementation process is as follows:
[0033] In actual application, a working fluid is drawn out from the drain pump and transported to the cooler 21 through the cooling pipe 26. The cooling water input from the cooler 21 cools the drawn working fluid, and the cooled working fluid is then transported back to the mechanical seal dynamic ring of the drain pump by the cooling pipe 26. The cooled working fluid passes through the gap and the dynamic and static sealing surfaces and enters the first-stage impeller inlet of the drain pump. The temperature parameters of the mechanical seal system of the drain pump can be controlled within a relatively constant and reasonable range, the service life and operating stability of the mechanical seal of the drain pump can be improved, and a zero-leakage, high-efficiency heater drain pump system can be formed. The reliability of equipment operation is improved, maintenance costs are reduced, and the heat loss of the working fluid is ensured to be fully recovered by the cooler 21.
[0034] Embodiment 2
[0035] The external cooling system of the heater drain pump of a coal-fired power plant is different from the first embodiment in that Figure 3 As shown, the delivery pipe 25 is welded with a spray pipe extending to a preset length on the water outlet end of the inner wall of the cooler 21. The preset length is set according to the actual size of the inside of the cooler 21. The spray pipe includes an inclined section 27 and a soft section 28. The soft section 28 is fixed to the inclined section 27 by bonding or heat welding to ensure that it does not fall off. The inclined section 27 is inclined toward the port where the cooling pipe 26 enters the cooler 21. The angle between the inclined section 27 and the horizontal plane is 35°, and the length of the soft section 28 is one fifth of the length of the inclined section 27.
[0036] Since the temperature of the industrial water or desalted water used as the cooling medium tends to be saturated after working in the cooler 21 for a period of time, the cooling effect is reduced. Through the setting of the injection pipe, the water pressure of the incoming water can drive the soft section 28 to swing to a certain extent, so that the newly entering industrial water or desalted water can be cooled from the inlet end of the cooling pipe 26 in the cooler 21. Stirring the industrial water or desalted water can make the cooling pipe 26 contact the cooling medium as quickly as possible for cooling, ensuring that the outlet water temperature meets the requirements and improving the heat exchange efficiency.
[0037] The above is only an embodiment of the utility model, and the common knowledge such as the known specific structure and characteristics in the scheme is not described in detail here. It should be pointed out that for those skilled in the art, several deformations and improvements can be made without departing from the structure of the utility model, which should also be regarded as the protection scope of the utility model, and these will not affect the effect of the implementation of the utility model and the practicality of the patent. The scope of protection required by this application shall be based on the content of its claims, and the specific implementation methods and other records in the specification can be used to interpret the content of the claims.
Claims
1. An external cooling system for a heater drain pump in a coal-fired power plant, characterized in that: It includes a cooling pipe for conducting working medium from the outlet of the drain pump, the cooling pipe is connected to a cooler, and the cooler is connected to a delivery pipeline for conveying demineralized water or industrial water for cooling; One end of the cooling pipe leading out from the cooler is connected to the mechanical seal dynamic ring of the drain pump, so that the cooled working medium enters the first-stage impeller inlet of the drain pump after passing through the gap and the dynamic and static sealing surfaces.
2. According to claim 1, the external cooling system for the heater drain pump of a coal-fired power plant is characterized by: The heat exchange area and cooling water consumption of the cooler increase progressively as the capacity of the drain pump increases.
3. The external cooling system for the heater drain pump of a coal-fired power plant according to claim 1, characterized in that: A first valve is connected to one end of the cooling pipe leading out from the cooler, and a second valve is connected to the cooling pipe at the outlet end of the drain pump.
4. The external cooling system for the heater drain pump of a coal-fired power plant according to claim 1, characterized in that: The cooling pipe is introduced from the radial direction of the drain pump.
5. The external cooling system for the heater drain pump of a coal-fired power plant according to claim 1, characterized in that: The water inlet end and the water outlet end of the delivery pipeline are respectively connected with control valves.
6. The external cooling system for the heater drain pump of a coal-fired power plant according to claim 1, characterized in that: The mechanical seal is a container-type bellows mechanical seal.
7. The external cooling system for the heater drain pump of a coal-fired power plant according to claim 1, characterized in that: The delivery pipeline is fixedly provided with a spray pipe extending to a preset length on the water outlet end of the inner wall of the cooler. The spray pipe includes an inclined section and a soft section. The inclined section is inclined toward the port where the cooling pipe enters the cooler.
8. The external cooling system for the heater drain pump of a coal-fired power plant according to claim 7, characterized in that: The angle between the inclined section and the horizontal plane is 35°, and the length of the soft section is one fifth of the length of the inclined section.