Drainage system of high-low pressure heater

Abstract

The invention discloses a high-low pressure heater drainage system which comprises a plurality of high-low pressure heaters provided with drainage outlets. The connecting pipeline is used for communicating all the high-low pressure heaters with one another; wherein the connecting pipeline is provided with a main pipeline communicated with the drainage outlet and a bypass connected with the main pipeline in parallel, the main pipeline is provided with a pneumatic control valve, and the bypass is provided with a gate valve. According to the drainage system of the high-low pressure heater, by arranging a parallel redundant loop of the main pipeline pneumatic adjusting valve and the bypass gate valve, the pneumatic adjusting valve automatically adjusts drainage flow according to signals in the normal state during use, and the control precision is obviously improved; compared with a common gate valve or a two-phase flow valve and the like, the drainage control precision is improved, and unit shutdown caused by faults due to the fact that a single-pipeline single-valve system is free of redundancy is avoided.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of heater drainage, in particular to a high-low pressure heater drainage system. BACKGROUND

[0002] In a thermal power generation system, a high-low pressure heater is a key auxiliary equipment, which heats the boiler feed water by using steam turbine extraction to improve the thermal cycle efficiency. The core function of its drainage system is to discharge the condensate (drainage) in the heater in time, while maintaining the water level in the heater stable, avoiding affecting the heat exchange effect or causing equipment failure due to abnormal water level. The traditional high-low pressure heater drainage system usually adopts the structure of gas-liquid two-phase valve or manual drainage valve cooperating with fixed pipe diameter pipeline, and realizes drainage control through manual adjustment or simple liquid level linkage. This kind of system relies on the topology structure of "single valve control + straight pipeline", and it is difficult to accurately adapt to the dynamic change of drainage flow when the unit load fluctuates.

[0003] However, the prior art has significant defects: first, in the single valve control mode, the valve adjustment lags behind the water level change, resulting in large fluctuation of the heater water level, which not only reduces the heat exchange efficiency, but also may cause the risk of turbine water inlet; second, the system lacks redundancy design, when the valve is stuck or fails, the unit needs to be shut down for maintenance, affecting the operation reliability of the unit; at the same time, the traditional variable diameter structure causes large fluid resistance, and the local resistance coefficient is 40% higher than the optimal design. These problems make the existing drainage system difficult to meet the needs of modern unit efficient operation in terms of control accuracy, safety and operation and maintenance cost. SUMMARY

[0004] In view of the problems of insufficient control accuracy and safety of the existing high-low pressure heater drainage system, the present application is proposed.

[0005] Therefore, the purpose of the present application is to provide a high-low pressure heater drainage system, which aims to improve the control accuracy and safety.

[0006] To solve the above technical problems, the present application provides the following technical scheme: a plurality of high-low pressure heaters are provided, and each high-low pressure heater is provided with a drainage outlet; a connecting pipeline is used to connect each high-low pressure heater; wherein the connecting pipeline is provided with a main pipeline communicated with the drainage outlet and a bypass pipeline connected in parallel with the main pipeline, a pneumatic regulating valve is arranged on the main pipeline, and a gate valve is arranged on the bypass pipeline.

[0007] As a preferred scheme of the high-low pressure heater drainage system, the inlet end of the pneumatic regulating valve is provided with an inlet reducing portion, the outlet end of the pneumatic regulating valve is provided with an outlet reducing portion, the inlet reducing portion is used for connecting the inlet of the pneumatic regulating valve with the main pipeline, and the outlet reducing portion is used for connecting the outlet of the pneumatic regulating valve with the drainage pipeline.

[0008] As a preferred scheme of the high-low pressure heater drainage system, the inlet reducing portion is connected with a seamless pipe, the seamless pipe is communicated with the main pipeline, the outlet reducing portion is connected with a drainage pipeline, and the diameter of the drainage pipeline is greater than that of the main pipeline.

[0009] As a preferred scheme of the high-low pressure heater drainage system, the diameter of the inlet reducing portion decreases from big to small along the water flow direction, the diameter of the outlet reducing portion increases from small to big along the water flow direction, and the inlet reducing portion and the outlet reducing portion are both hollow circular truncated cone pipelines.

[0010] As a preferred scheme of the high-low pressure heater drainage system, the acute angle of the isosceles trapezoid projected by the outlet reducing portion is smaller than the acute angle of the isosceles trapezoid projected by the inlet reducing portion.

[0011] As a preferred scheme of the high-low pressure heater drainage system, the inlet side of the pneumatic regulating valve is further provided with a first gate valve, the bypass is provided with a second gate valve, and the first gate valve and the second gate valve are both manual valves.

[0012] As a preferred scheme of the high-low pressure heater drainage system, the input end of the bypass is connected to the inlet side of the pneumatic regulating valve on the main pipeline, and the output end of the bypass is connected to the outlet side of the pneumatic regulating valve on the main pipeline.

[0013] As a preferred scheme of the high-low pressure heater drainage system, the connecting pipeline is provided with an inspection pipeline communicated with the main pipeline, and the output end of the inspection pipeline is provided with a blocking plate.

[0014] As a preferred scheme of the high-low pressure heater drainage system, the connecting pipeline is provided with a drainage pipeline communicated with the drainage outlet, and the drainage pipeline is communicated with the main pipeline and the bypass.

[0015] As a preferred scheme of the high-low pressure heater drainage system, the connection between the drainage pipeline and the drainage outlet is provided with a reducer for changing the liquid flow rate and pressure.

[0016] The beneficial effects of the present application are as follows: the present application sets a parallel redundancy circuit of the main pipeline pneumatic regulating valve and the bypass gate valve, the pneumatic regulating valve automatically adjusts the drain flow according to the signal in the normal state during use, the control precision is obviously improved, the bypass gate valve is manually opened to connect the flow when the valve fails, compared with the commonly used gate valve or two-phase flow valve, the drain control precision is improved, and the unit shutdown caused by the failure of the single pipeline single valve system without redundancy is avoided,

[0017] By setting the reduced-diameter inlet reducing portion at the inlet end of the pneumatic regulating valve and the expanded-diameter outlet reducing portion at the outlet end, the inlet reducing portion increases the drain flow rate of the main pipeline to match the high-efficiency interval of the valve during use, and the outlet reducing portion reduces the high-speed pulse flow by gradually expanding the diameter, thereby improving the uniformity of fluid flow state, reducing the pipeline vibration amplitude, reducing the annual corrosion speed of the downstream pipeline, reducing the damage of the pipeline, and improving the safety. BRIEF DESCRIPTION OF DRAWINGS

[0018] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings needed in the embodiment description will be briefly introduced as follows. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0019] Figure 1 It is a schematic diagram of the high-low pressure heater drain system of the present application.

[0020] Figure 2 It is a schematic diagram of the high pressure heater of the high-low pressure heater drain system of the present application.

[0021] Figure 3 It is a schematic diagram of the low pressure heater of the high-low pressure heater drain system of the present application.

[0022] Figure 4 It is a schematic diagram of the connecting pipeline of the high-low pressure heater drain system of the present application.

[0023] Figure 5 It is another schematic diagram of the connecting pipeline of the high-low pressure heater drain system of the present application.

[0024] Figure 6 It is a projection view of the inlet reducing portion and the outlet reducing portion of the high-low pressure heater drain system of the present application. DETAILED DESCRIPTION

[0025] In order to make the above-mentioned purposes, features and advantages of the present application more obvious and easy to understand, the specific embodiments of the present application will be described in detail below with reference to the drawings of the specification.

[0026] In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present application. However, it will be apparent to one skilled in the art that the present application can be practiced without the specific details set forth in this description. In other instances, well-known methods, procedures, components, and circuits have not been described in detail so as not to unnecessarily obscure aspects of the present application.

[0027] Second, the "one embodiment" or "an embodiment" described herein as including a particular implementation as part of the present application can include a particular feature, structure, or characteristic described herein but it need not. The various appearances of "in one embodiment" or "an embodiment" are not necessarily all referring to the same embodiment.

[0028] Third, the application is described in connection with exemplary embodiments. The terms "exemplary" and "in one embodiment" are used herein to mean in one embodiment, an example or instance of the item being described. Although the terms "exemplary" and "in one embodiment" can be used in the description of one or more embodiments of the present application, none of the features described in the exemplary embodiments are required in all embodiments of the present application, and the terms should not be construed to limit the scope of the application or the patent to the one or more embodiments described herein.

[0029] Embodiment 1

[0030] Reference Figures 1-3 For the first embodiment of the present application, a high-low pressure heater 100 drainage system is provided, which comprises a plurality of high-low pressure heaters 100, the high-low pressure heater 100 is provided with a drainage outlet 106; connecting pipe 200, for connecting each of the high-low pressure heater 100 with each other; wherein the connecting pipe 200 is provided with the main pipe 202 communicated with the drainage outlet 106 and the bypass 203 parallel to the main pipe 202, the main pipe 202 is provided with pneumatic control valve 202b, the bypass 203 is provided with gate valve, the main pipe 202 and the bypass 203 are provided with branch hanger 207, which is used to reduce the vibration of the pipeline and support the pipeline, the pneumatic control valve 202b adopts air closed type diaphragm actuator, which drives the valve core to move up and down by receiving the pneumatic signal output by the distributed control system, to realize the continuous adjustment of the drainage flow. Its core principle of action is as follows: when the water level of high pressure heater rises, the distributed control system sends the pneumatic signal to increase (such as from 8 mA to 16 mA), the diaphragm of the actuator is pressed down to drive the valve core to move up, the valve opening is increased, and the drainage flow is increased to reduce the water level; on the contrary, when the water level decreases, the pneumatic signal decreases, the valve core moves down to close the valve port, and the drainage flow is reduced to maintain the stability of the water level, and the pneumatic control valve 202b can automatically and accurately adjust the drainage flow.

[0031] Wherein, the high and low pressure heater 100 includes but is not limited to the first high pressure heater 101, the second high pressure heater 102, the third high pressure heater 103, the first low pressure heater 104, the second low pressure heater 105, the drain outlet 106 of the first high pressure heater 101 is communicated with the input water port of the second high pressure heater 102 through the connecting pipeline 200, the drain outlet 106 of the second high pressure heater 102 is communicated with the drain outlet 106 of the third high pressure heater 103 through the connecting pipeline 200, the drain outlet 106 of the third high pressure heater 103 is communicated with the deaerator, and the first low pressure heater 104 and the second low pressure heater 105 are similar.

[0032] In the use process, under the normal state, the pneumatic regulating valve 202b on the main pipeline 202 is always opened, the gate valve on the bypass 203 is always closed, the drain of the first high pressure heater 101 enters the main pipeline 202 of the connecting pipeline 200 from the drain outlet 106, and since the gate valve in the bypass 203 is closed, the drain can only pass through the main pipeline 202 at this time, the drain rushes through the pneumatic regulating valve 202b, the pneumatic regulating valve 202b is automatically adjusted according to the pressure, and then the drain is sent from the main pipeline 202 to the second high pressure heater 102, after the use of the second high pressure heater 102, the drain of the second high pressure heater 102 enters the main pipeline 202 of the next connecting pipeline 200 from the drain outlet 106, and then enters the third high pressure heater 103 from the main pipeline 202 through the pneumatic regulating valve 202b, and the like, after passing through several high pressure heaters, the drain is sent into the deaerator C through the connecting pipeline 200, and another part of the drain is branched to the chemical sampling pipeline Q for analyzing the water quality of the drain. Similarly, the first low pressure heater 104 drain and the second low pressure heater 105 drain principle is similar to the high pressure heater. When the pneumatic regulating valve 202b fails, the gate valve is manually opened, temporarily taking over the flow of the main pipeline 202, at this time the drain is changed to flow through the bypass 203, playing a double valve redundant control role.

[0033] Embodiment 2

[0034] Reference Figure 4 、 Figure 5 , it is the second embodiment of the application, which is different from the first embodiment: the inlet end of the pneumatic regulating valve 202b is provided with an inlet reducing portion 202c, the outlet end of the pneumatic regulating valve 202b is provided with an outlet reducing portion 202d, the inlet reducing portion 202c is used for communicating the inlet of the pneumatic regulating valve 202b with the main pipeline 202, and the outlet reducing portion 202d is used for communicating the outlet of the pneumatic regulating valve 202b with the drain pipeline 204.

[0035] The inlet reducing section 202c is reduced in diameter, the outlet reducing section 202d is expanded in diameter, and the steam from the main pipeline 202 enters the pneumatic regulating valve 202b after the flow rate is increased by the inlet reducing section 202c, and the steam output by the pneumatic regulating valve 202b is discharged after the flow rate is reduced by the outlet reducing section 202d.

[0036] The inlet reducing section 202c is connected with a seamless pipe, which is preferably a seamless steel pipe, and the seamless pipe is in communication with the main pipeline 202, and the outlet reducing section 202d is connected with a drain pipe 204, and the diameter of the drain pipe 204 is greater than that of the main pipeline 202. The seamless pipe is connected with the main pipeline 202 as a part of the inlet reducing section 202c of the pneumatic regulating valve 202b, and by setting the diameter of the drain pipe 204 to be larger, the flow rate of the steam can be reduced during drainage, and the impact on the pipeline can be reduced.

[0037] The diameter of the inlet reducing section 202c decreases from large to small in the direction of water flow, and the diameter of the outlet reducing section 202d increases from small to large in the direction of water flow, and the inlet reducing section 202c and the outlet reducing section 202d are both hollow circular truncated cone pipes.

[0038] Referring to Figure 6 The acute angle R1 of the isosceles trapezoid projected in the front view of the outlet reducing section 202d is smaller than the acute angle R2 of the isosceles trapezoid projected in the front view of the inlet reducing section 202c. Compared with commonly used two-phase flow valves, the pneumatic regulating valve 202b is shorter in length, the straight section of the main pipeline 202 is extended by the seamless pipe, and the transition area of the reducing section is compressed, so that the flow state of the fluid can be optimized, and the uniformity of the flow rate of the steam before the regulating valve can be improved.

[0039] During use, the flow rate of the fluid in the steam pipeline 201 of the high-pressure heater is not uniform, and there is a flow deviation phenomenon. The inlet reducing section 202c gradually reduces in diameter to force the flow rate of the fluid to be redistributed, so that the flow state of the steam entering the pneumatic regulating valve 202b is more uniform. And because the pneumatic regulating valve 202b has an optimal working flow rate range (such as a flow rate in the range of 3-8 m / s), the inlet reducing section increases the flow rate of the fluid (such as the flow rate of the main pipeline 202 being 2 m / s and the flow rate of the inlet of the pneumatic regulating valve 202b being 5 m / s), so that the pneumatic regulating valve 202b works in the high-efficiency zone, and the response time is shortened. And the gradually reducing structure of the inlet reducing section 202c can reduce the flow dead zone (impurities are prone to deposit in the corners of the original pipeline), so that the fluid passes through the reducing section in a “scouring” manner, and the probability of accumulation of impurities such as iron oxide and scale at the inlet of the regulating valve is reduced.

[0040] The outlet fluid of the pneumatic regulating valve 202b is throttled between the valve core and the valve seat, and the pneumatic regulating valve 202b needs to dynamically change the throttling degree in order to accurately control the amount of water vapor, so the opening degree of the valve core dynamically changes, causing the flow area in the pneumatic regulating valve 202b to change, so the fluid forms a high-speed pulse, and the water vapor is high-temperature and high-pressure saturated water, and a small amount of steam is mixed in the water flow, which may suddenly expand or condense when passing through the pneumatic regulating valve 202b, further intensifying the fluctuations of flow rate and pressure, and the water vapor sent by the pneumatic regulating valve 202b directly impacts the downstream pipeline, accelerating the thinning of the wall thickness. The outlet reducing portion 202d converts kinetic energy into pressure energy by gradually expanding the diameter, reducing the erosion of the pipeline by turbulent flow. The pressure pulsation of high-speed fluid is the root cause of pipeline vibration. The outlet reducing portion 202d reduces the amplitude of pressure fluctuation through flow state buffering. The fluid throttled by the regulating valve is in a “turbulent jet” state, and the outlet reducing portion expands and rectifies the flow, so that the fluid restores the characteristics of laminar flow in the downstream pipeline, reduces the additional resistance caused by turbulent flow, and improves the overall energy efficiency of the water vapor system.

[0041] The rest of the structure is the same as that of example 1.

[0042] Example 3

[0043] Referring to Figures 2-5 For the third embodiment of the application, which is different from the second embodiment, the inlet side of the pneumatic regulating valve 202b is further provided with a first gate valve 202a, and the bypass 203 is provided with a second gate valve 203a, and the first gate valve 202a and the second gate valve 203a are both manual valves. The first gate valve 202a is arranged on the inlet side of the pneumatic regulating valve 202b, and if the first gate valve 202a is closed, the pneumatic regulating valve 202b can be disconnected.

[0044] The input end of the bypass 203 is connected to the inlet side of the pneumatic regulating valve 202b on the main pipeline 202, the output end of the bypass 203 is connected to the outlet side of the pneumatic regulating valve 202b on the main pipeline 202, the pipeline of the first gate valve 202a (the inlet side of the pneumatic regulating valve 202b) and the second gate valve 203a (the bypass 203) forms a “main pipeline-bypass 203” and return circuit, the bypass 203 is connected to the front of the inlet of the pneumatic regulating valve 202b and the rear of the outlet of the pneumatic regulating valve 202b respectively, forming a complete redundant bypass path, the bypass 203 and the second gate valve 203a play a double valve redundant control role, when the pneumatic regulating valve 202b on the main pipeline 202 fails, the first gate valve 202a can be closed, the second gate valve 203a can be opened, the main pipeline 202 can be closed, and the bypass 203 can be opened, at this time, the bypass 203 takes over the flow of the main pipeline 202, the first gate valve 202a can cut off the upstream flow of the pneumatic regulating valve 202b alone, and the first gate valve 202a can be isolated from the main system during valve maintenance, when the second gate valve 203a is opened, the bypass 203 takes over the flow of the main pipeline 202, and the control mode switching of “pneumatic regulation-manual bypass” is realized.

[0045] The connecting pipeline 200 is provided with a maintenance pipeline 205 in communication with the main pipeline 202, the output end of the maintenance pipeline 205 is provided with a blank plate 206, the maintenance pipeline 205 is led out from the side of the main pipeline 202, the pipe diameter is smaller than that of the main pipeline 202, the end is provided with a flange-connected blank plate 206, the blank plate 206 is sealed with the pipeline through the flange, the blank plate 206 is opened before maintenance, and the accumulated water and excess pressure in the main pipeline 202 can be discharged, thereby providing safe conditions for maintenance.

[0046] The connecting pipeline 200 is provided with a drain pipeline 201 in communication with the drain outlet 106, the drain pipeline 201 is in communication with the main pipeline 202 and the bypass 203, a reducer 201a is arranged at the connection position of the drain pipeline 201 and the drain outlet 106, for changing the flow rate and pressure of the liquid, the reducer 201a is a conical frustum-shaped pipeline with different diameters at two ends, the large end is welded with the drain pipeline 201, the small end is flange-connected with the drain outlet 106 of the high-low pressure heater 100, and the taper of the reducer is gentle. Through the reducer structure, the low flow rate of the heater outlet is increased, so as to match the optimal flow rate interval of the main pipeline 202, and the outlet pressure is slightly increased.

[0047] The remaining structure is the same as that of example 2.

[0048] It is important to note that the construction and arrangement of the application shown in the various exemplary embodiments is illustrative only. Although only a few embodiments have been described in detail in this disclosure, those skilled in the art who review this disclosure will readily appreciate that many modifications are possible (e.g., variations in sizes, dimensions, structures, shapes and proportions of the various elements, values of parameters, mounting arrangements, use of materials, colors, orientations, etc.) without materially departing from the novel teachings and advantages of the subject matter described in the application. For example, elements shown as integrally formed can be constructed of multiple parts or elements, the position of elements can be reversed or otherwise varied, and the nature or number of elements can be altered or varied. The order or sequence of any process or method steps can be varied or re-sequenced without materially affecting the application. Accordingly, all such modifications are intended to be included within the scope of the present application. The application can be implemented in any suitable hardware, software, firmware, or combination thereof.

[0049] Furthermore, in order to provide a concise description of exemplary embodiments, not all features of an actual implementation can be described (i.e., those pertaining to the

[0050] It should be noted that the above-mentioned embodiments are only used to illustrate the technical solutions of the present application, not to limit the present application. Although the present application has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present application can be modified or replaced by equivalents without departing from the spirit and scope of the present application, which should be covered by the claims of the present application.

Claims

1. A high-low pressure heater drain system characterized by: The utility model relates to a kind of high-low pressure heater connection pipeline and high-low pressure heater connection pipeline, including, Several high-low pressure heaters (100), the high-low pressure heater (100) is equipped with drain outlet (106); Connecting pipeline (200) for intercommunication of each high-low pressure heater (100); Wherein, the connecting pipeline (200) is equipped with main pipeline (202) being communicated with the drain outlet (106) and bypass (203) being connected with the main pipeline (202), the main pipeline (202) is equipped with pneumatic control valve (202b), the bypass (203) is equipped with gate valve.

2. The high-low pressure heater drain system of claim 1, wherein: The inlet end of the pneumatic control valve (202b) is provided with an inlet reducing portion (202c), and the outlet end of the pneumatic control valve (202b) is provided with an outlet reducing portion (202d). The inlet reducing portion (202c) is used to communicate the inlet of the pneumatic control valve (202b) with the main pipeline (202), and the outlet reducing portion (202d) is used to communicate the outlet of the pneumatic control valve (202b) with the drain pipeline (204).

3. The high-low pressure heater drain system of claim 2, wherein: The inlet reducing portion (202c) is connected with a seamless pipe, which is communicated with the main pipeline (202). The outlet reducing portion (202d) is connected with a drain pipeline (204), and the diameter of the drain pipeline (204) is larger than that of the main pipeline (202).

4. The high-low pressure heater drainage system of claim 2 or 3, wherein: The diameter of the inlet reducing portion (202c) decreases from large to small in the direction of water flow, and the diameter of the outlet reducing portion (202d) increases from small to large in the direction of water flow. Both the inlet reducing portion (202c) and the outlet reducing portion (202d) are hollow circular truncated cone pipelines.

5. The high-low pressure heater drain system of claim 4, wherein: The acute angle of the isosceles trapezoid projected by the outlet reducing portion (202d) is smaller than the acute angle of the isosceles trapezoid projected by the inlet reducing portion (202c).

6. The high-low pressure heater drain system of any of claims 1, 2, 3, 5, wherein: The inlet side of the pneumatic control valve (202b) is further provided with a first gate valve (202a), and the bypass (203) is provided with a second gate valve (203a). Both the first gate valve (202a) and the second gate valve (203a) are hand-operated valves.

7. The high-low pressure heater drain system of claim 6, wherein: The input end of the bypass (203) is connected to the inlet side of the pneumatic control valve (202b) on the main pipeline (202), and the output end of the bypass (203) is connected to the outlet side of the pneumatic control valve (202b) on the main pipeline (202).

8. The high-low pressure heater drain system of any one of claims 1, 2, 3, 5, 7, wherein: The connecting pipeline (200) is provided with an inspection pipeline (205) communicated with the main pipeline (202), and the output end of the inspection pipeline (205) is provided with a blanking plate (206).

9. The high-low pressure heater drain system of claim 8, wherein: The connecting pipeline (200) is provided with a drain pipeline (201) communicated with the drain outlet (106), and the drain pipeline (201) is communicated with the main pipeline (202) and the bypass (203).

10. The high-low pressure heater drain system of claim 9, wherein: The connection between the drain pipeline (201) and the drain outlet (106) is provided with a reducer (201a) for changing the flow rate and pressure of liquid.

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