A low-load stable operation and drainage recovery system for low-pressure drain pump

Abstract

The present invention discloses a low-load stable operation and drainage recovery system for a low-pressure heater drain pump, comprising a first drainage system, a second drainage system, a cooling water pipe, a mixed cooling water tank and a low-pressure heater drain pump; wherein: the outlet main pipe of the low-pressure heater drain pump is connected to the first drainage system and the second drainage system, and a first regulating valve is provided on the pipeline connecting the outlet main pipe of the low-pressure heater drain pump and the first drainage system, and a second regulating valve is provided on the pipeline connecting the outlet main pipe of the low-pressure heater drain pump and the second drainage system; the inlet main pipe of the low-pressure heater drain pump is connected to the mixed cooling water tank; the low-pressure heater drain pipe of the second drainage system is connected to the mixed cooling water tank; the cooling water pipe is connected to the mixed cooling water tank, and the cooling water pipe transports cooling water to the mixed cooling water tank to mix and cool the liquid in the mixed cooling water tank. The present invention has a simple structure, enables the low-pressure heater drain pump to operate stably at low load, ensures reliable operation of the equipment, and is energy-saving and environmentally friendly.

Description

Technical Field

[0001] The present invention relates to the technical field of power generation equipment, and in particular to a low-load stable operation of a low-pressure heater drain pump and a drain recovery system. Background Art

[0002] At present, the peak load regulation of thermal power units is becoming more and more frequent, and the low load time of the units is increasing. Improving the operating stability of equipment during low load has become a challenge faced by power plants. At present, a lot of drain water from the units is not recycled, or high-temperature drain water is directly discharged into the drain expansion tank, resulting in energy waste and not meeting energy-saving requirements.

[0003] In Anhui, the peak load regulation of thermal power units is becoming more and more frequent, and the low-load time of units is increasing. How to ensure the stable operation of equipment during low-load period has become a challenge faced by power plants. At present, the low-load operation of the low-pressure drain pump of unit #1 in our plant is unstable; the current of the low-pressure drain pump is unstable, and the control quality of the water level of #6 low-pressure drain is poor; a lot of drain water of the unit is not recycled, or the high-temperature drain water is directly discharged to the drain expansion tank, resulting in energy waste, which does not meet the energy-saving requirements.

[0004] When the unit is running at low load, the drainage volume of No. 5 and No. 6 low-pressure heaters is greatly reduced, but the drainage temperature remains basically unchanged, resulting in insufficient flow of the low-pressure heater drain pump, leading to unstable operation. Specifically, the current motor current of the low-pressure heater drain pump fluctuates greatly, and the water level control of No. 6 low-pressure heater is unstable, resulting in the low-pressure heater being unable to operate reliably and stably. Summary of the invention

[0005] In order to solve the technical problems existing in the background technology, the present invention proposes a low-load stable operation of a low-pressure drain pump and a drain recovery system.

[0006] The present invention provides a low-load stable operation and drainage recovery system for a low-pressure heater drain pump, comprising a first drainage system, a second drainage system, a cooling water pipe, a mixed cooling water tank and a low-pressure heater drain pump; wherein:

[0007] The outlet main pipe of the low-pressure heater drain pump is connected to the first drain system and the second drain system, and a first regulating valve is provided on the pipeline connecting the outlet main pipe of the low-pressure heater drain pump and the first drain system, and a second regulating valve is provided on the pipeline connecting the outlet main pipe of the low-pressure heater drain pump and the second drain system;

[0008] The water inlet main pipe of the low-pressure heater drain pump is connected to the mixed cooling water tank;

[0009] The low-pressure heater drain pipe of the second drain system is connected to the mixed cooling water tank;

[0010] The cooling water pipe is connected with the mixed cooling water tank, and the cooling water pipe conveys the cooling water to the mixed cooling water tank to perform mixed cooling on the liquid in the mixed cooling water tank.

[0011] As a further optimized solution of the present invention, a third valve is provided on the water inlet main pipe of the low-pressure heater drain pump, and a fourth valve is provided on the water outlet main pipe of the low-pressure heater drain pump.

[0012] As a further optimized solution of the present invention, a fifth regulating valve is provided on the cooling water pipe.

[0013] As a further optimized solution of the present invention, it also includes a lithium bromide refrigeration unit drain pipe, and the lithium bromide refrigeration unit drain pipe is connected to the mixed cooling water tank.

[0014] As a further optimized solution of the present invention, the mixed cooling water tank includes a tank body and a mixed water supply member, wherein:

[0015] The box body has a water storage cavity, and the mixing water supply component is arranged on the box body.

[0016] The mixing water supply component is provided with a mixing flow channel, an outer cooling cavity and an inner cooling cavity. The mixing flow channel is located between the outer cooling cavity and the inner cooling cavity. The low-pressure drain pipe of the second drain system is connected with the mixing flow channel. The cooling water pipeline is connected with the outer cooling cavity. There is a connecting through hole between the outer cooling cavity and the mixing flow channel. The connecting through hole connects the outer cooling cavity and the mixing flow channel. The bottom of the mixing flow channel is connected with the water storage cavity. A cooling substance is arranged in the inner cooling cavity.

[0017] As a further optimized solution of the present invention, the cooling substance is ice.

[0018] As a further optimized solution of the present invention, a cooling channel is provided between the inner cooling cavity and the mixing flow channel, and the cooling channel is used to connect the inner cooling cavity and the mixing flow channel.

[0019] As a further optimized solution of the present invention, the cooling channel gradually slopes downward from an end away from the mixing flow channel toward a direction close to the mixing flow channel.

[0020] As a further optimized solution of the present invention, the connecting through hole gradually slopes downward from an end away from the mixing flow channel toward a direction close to the mixing flow channel.

[0021] As a further optimized solution of the present invention, the mixing channel is spiral in the vertical direction.

[0022] In the present invention, the low-load stable operation and drain recovery system of the low-pressure heater drain pump can ensure the low-load operation stability and drain recovery of the low-pressure heater drain pump at any load stage of the unit by adjusting the disturbance-free online switching capability of the first regulating valve and the second regulating valve;

[0023] In order to achieve the purpose of energy saving, the high-temperature drain water is discharged to the mixed cooling water tank, which has achieved the purpose of reducing waste heat discharge and recovering the waste heat of drain water;

[0024] The low-pressure drain pump can be selected to the main inlet pipe of the low-pressure water supply side of the first drain system or the main inlet pipe of the low-pressure water supply side of the first drain system according to the temperature, so as to achieve the effect of energy saving;

[0025] A mixed cooling water tank is arranged near the low-pressure heater drain pump, which collects drain water and cools the drain water at the inlet of the low-pressure heater drain pump.

[0026] Additional aspects and advantages of the present invention will be given in part in the following description and in part will be obvious from the following description, or will be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is a schematic diagram of the structure of the present invention;

[0028] Figure 2 This is a schematic diagram of the structure of the mixed cooling water tank of the present invention;

[0029] Figure 3 It is a cross-sectional view of the mixing cooling water tank of the present invention. DETAILED DESCRIPTION

[0030] Embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar symbols throughout represent the same or similar elements or elements with the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and cannot be understood as limiting the present invention.

[0031] It should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0032] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of the present invention, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0033] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral one; it can be a mechanical connection, an electrical connection, or communication with each other; it can be a direct connection, or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0034] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, a first feature being "above", "above" or "above" a second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. A first feature being "below", "below" or "below" a second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0035] like Figure 1-3 The low-load stable operation and drainage recovery system of a low-pressure heater drain pump shown in the figure comprises a first drainage system 1, a second drainage system 2, a cooling water pipe 3, a mixed cooling water tank 4 and a low-pressure heater drain pump 5; wherein:

[0036] The outlet main pipe 6 of the low-pressure drain pump 5 is connected to the first drain system 1 and the second drain system 2, and a first regulating valve 7 is provided on the pipeline connecting the outlet main pipe 6 of the low-pressure drain pump 5 and the first drain system 1, and a second regulating valve 8 is provided on the pipeline connecting the outlet main pipe 6 of the low-pressure drain pump 5 and the second drain system 2;

[0037] The water inlet main pipe 9 of the low-pressure heater drain pump 5 is connected to the mixed cooling water tank 4;

[0038] The low-pressure heater drain pipe 10 of the second drain system 2 is connected to the mixed cooling water tank 4;

[0039] The cooling water pipe 3 is connected to the mixing cooling water tank 4 , and the cooling water pipe 3 transports the cooling water to the mixing cooling water tank 4 to perform mixing cooling on the liquid in the mixing cooling water tank 4 .

[0040] A third valve 11 is provided on the water inlet main pipe 9 of the low-pressure heater drain pump 5 , and a fourth valve 12 is provided on the water outlet main pipe 6 of the low-pressure heater drain pump 5 .

[0041] A fifth regulating valve 13 is provided on the cooling water pipe 3 .

[0042] It also includes a lithium bromide refrigeration unit drain pipe 14, which is connected to the mixed cooling water tank 4.

[0043] The mixed cooling water tank 4 comprises a tank body 40 and a mixed water supply member 41, wherein:

[0044] The box body 40 has a water storage chamber 400, and a mixing water supply component 41 is arranged on the box body 40.

[0045] The mixing water supply component 41 is provided with a mixing flow channel 410, an outer cooling cavity 411 and an inner cooling cavity 412. The mixing flow channel 410 is located between the outer cooling cavity and the inner cooling cavity 412. The low-pressure drain pipe 10 of the second drain system 2 is connected with the mixing flow channel 410, and the cooling water pipe 3 is connected with the outer cooling cavity 411. There is a connecting through hole 15 between the outer cooling cavity 411 and the mixing flow channel 410. The connecting through hole 15 connects the outer cooling cavity 411 and the mixing flow channel 410. The bottom of the mixing flow channel 410 is connected with the water storage cavity 400, and a cooling substance is arranged in the inner cooling cavity 412.

[0046] The cooling substance is ice.

[0047] A cooling channel 16 is provided between the inner cooling cavity 412 and the mixing flow channel 410 , and the cooling channel 16 is used to connect the inner cooling cavity 412 and the mixing flow channel 410 .

[0048] The cooling channel 16 gradually slopes downward from an end away from the mixing flow channel 410 toward a direction close to the mixing flow channel 410 .

[0049] The connecting through hole 15 gradually slopes downward from an end away from the mixing flow channel 410 to a direction close to the mixing flow channel 410 .

[0050] The mixing channel 410 is in a spiral shape along the vertical direction.

[0051] During the working process of this embodiment:

[0052] Considering the problem of matching the inlet and outlet temperatures of the low-pressure water supply side of the second drainage system 2 with the outlet temperature of the low-pressure water supply pump 5, a first regulating valve 7 and a second regulating valve 8 are provided at the outlet of the low-pressure water supply pump 5 to achieve the purpose of energy saving;

[0053] Considering that the drainage volume of the first drainage system 1 and the second drainage system 2 is small, unstable, and the drainage temperature is high when the low-pressure heater is under low load, a mixed cooling water tank 4 is set, which includes an outlet pipeline connected to the low-pressure heater drainage pump 5, a number of inlet pipelines (low-pressure heater drainage of the second drainage system 2, drainage of other systems, cooling water, etc.) and a water level gauge. The water level of the mixed cooling water tank is controlled by the motor frequency of the low-pressure heater drainage pump 5;

[0054] Due to the need to control the inlet temperature of the low-pressure heater drain pump 5, a mixed cooling water tank cooling water pipeline is set up, and the pipeline is provided with a flow regulating valve to control the inlet temperature of the low-pressure heater drain pump by controlling the cooling water flow;

[0055] In order to achieve the purpose of energy saving, the high-temperature drain water of the second drain system 2 is discharged to the mixed cooling water tank 4, which has achieved the purpose of reducing waste heat discharge and recovering the residual heat of drain water;

[0056] In the process of cooling the mixed liquid in the mixing water tank 4, a large amount of ice cubes are first placed in the inner cooling chamber 412, and then the outer cooling chamber 411 is filled with cooling water, and hot hydrophobic water is filled in the mixing channel 410. The high-temperature water flows from top to bottom along the mixing channel 410 through the spiral mixing channel 410. In this process, the cooling water in the outer cooling chamber 411 and the cold water in the inner cooling chamber 412 due to the melting of ice flow into the mixing channel 410 under the action of their own gravity, realizing heat exchange to cool the high-temperature hydrophobic water, and the mixed cooling effect is obvious.

[0057] In order to facilitate the control of the opening and closing of the LP heater drain pump 5 , in the present embodiment, preferably, a third valve 11 is provided on the water inlet main pipe 9 of the LP heater drain pump 5 , and a fourth valve 12 is provided on the water outlet main pipe 6 of the LP heater drain pump 5 .

[0058] In order to control the flow rate of water in the cooling water pipe 3 , in this embodiment, preferably, a fifth regulating valve 13 is provided on the cooling water pipe 3 .

[0059] In order to further achieve the purpose of energy saving, in this embodiment, preferably, a lithium bromide refrigeration unit drain pipe 14 is also included. The lithium bromide refrigeration unit drain pipe 14 is connected to the mixed cooling water tank 4 to recover the lithium bromide refrigeration unit drain to achieve the purpose of energy saving.

[0060] In order to further enhance the technical effect of the mixed cooling, in this embodiment, preferably, the mixed cooling water tank 4 includes a tank body 40 and a mixed water supply member 41, wherein:

[0061] The box body 40 has a water storage chamber 400, and a mixing water supply component 41 is arranged on the box body 40.

[0062] The mixing water supply component 41 is provided with a mixing flow channel 410, an outer cooling cavity 411 and an inner cooling cavity 412. The mixing flow channel 410 is located between the outer cooling cavity and the inner cooling cavity 412. The low-pressure drain pipe 10 of the second drain system 2 is connected with the mixing flow channel 410, and the cooling water pipe 3 is connected with the outer cooling cavity 411. There is a connecting through hole 15 between the outer cooling cavity 411 and the mixing flow channel 410. The connecting through hole 15 connects the outer cooling cavity 411 and the mixing flow channel 410. The bottom of the mixing flow channel 410 is connected with the water storage cavity 400, and a cooling substance is arranged in the inner cooling cavity 412.

[0063] In order to further increase the cooling effect, in this embodiment, preferably, the cooling material is ice.

[0064] In this embodiment, preferably, a cooling channel 16 is provided between the inner cooling cavity 412 and the mixing flow channel 410 , and the cooling channel 16 is used to connect the inner cooling cavity 412 and the mixing flow channel 410 .

[0065] In order to further increase the cooling effect, in the present embodiment, preferably, the cooling channel 16 gradually slopes downward from an end away from the mixing flow channel 410 toward a direction close to the mixing flow channel 410 .

[0066] In order to further increase the cooling effect, in the present embodiment, preferably, the connecting through hole 15 is gradually inclined downward from an end away from the mixing flow channel 410 to a direction close to the mixing flow channel 410 .

[0067] In order to further increase the cooling effect, in this embodiment, preferably, the mixing channel 410 is spiral along the vertical direction.

[0068] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A low-load stable operation and drainage recovery system for low-pressure steam heater drain pumps. It is characterized in that It comprises a first drain system (1), a second drain system (2), a cooling water pipe (3), a mixed cooling water tank (4) and a low-pressure heater drain pump (5); wherein: The outlet main pipe (6) of the low-pressure heater drain pump (5) is connected to the first drain system (1) and the second drain system (2), and a first regulating valve (7) is provided on the pipeline connecting the outlet main pipe (6) of the low-pressure heater drain pump (5) and the first drain system (1), and a second regulating valve (8) is provided on the pipeline connecting the outlet main pipe (6) of the low-pressure heater drain pump (5) and the second drain system (2); The water inlet main pipe (9) of the low-pressure heater drain pump (5) is connected to the mixed cooling water tank (4); The low-pressure heater drain pipe (10) of the second drain system (2) is in communication with the mixed cooling water tank (4); The cooling water pipe (3) is connected to the mixed cooling water tank (4), and the cooling water pipe (3) transports cooling water to the mixed cooling water tank (4) to perform mixed cooling on the liquid in the mixed cooling water tank (4); It also includes a lithium bromide refrigeration unit drain pipe (14), the lithium bromide refrigeration unit drain pipe (14) is connected to the mixed cooling water tank (4); The mixed cooling water tank (4) comprises a tank body (40) and a mixed water supply component (41), wherein: The box body (40) has a water storage chamber (400), and the mixing water supply component (41) is arranged on the box body (40). The mixing water supply component (41) is provided with a mixing flow channel (410), an outer cooling cavity (411) and an inner cooling cavity (412); the mixing flow channel (410) is located between the outer cooling cavity and the inner cooling cavity (412); the low-pressure drain pipe (10) of the second drain system (2) is connected to the mixing flow channel (410); the cooling water pipe (3) is connected to the outer cooling cavity (411); a connecting through hole (15) is provided between the outer cooling cavity (411) and the mixing flow channel (410); the connecting through hole (15) connects the outer cooling cavity (411) and the mixing flow channel (410); the lower part of the mixing flow channel (410) is connected to the water storage cavity (400); and a cooling substance is provided in the inner cooling cavity (412); A cooling channel (16) is provided between the inner cooling cavity (412) and the mixing flow channel (410), and the cooling channel (16) is used to connect the inner cooling cavity (412) and the mixing flow channel (410).

2. According to the low-load stable operation and drainage recovery system of the low-pressure heater drain pump of claim 1, It is characterized in that A third valve (11) is provided on the water inlet main pipe (9) of the low-pressure heater drain pump (5), and a fourth valve (12) is provided on the water outlet main pipe (6) of the low-pressure heater drain pump (5).

3. According to the low-load stable operation and drainage recovery system of the low-pressure heater drain pump of claim 1, It is characterized in that A fifth regulating valve (13) is provided on the cooling water pipe (3).

4. According to the low-load stable operation and drainage recovery system of the low-pressure heater drain pump of claim 1, It is characterized in that The cooling substance is ice.

5. According to the low-load stable operation and drainage recovery system of the low-pressure heater drain pump of claim 1, It is characterized in that The cooling channel (16) gradually slopes downward from an end away from the mixing flow channel (410) toward a direction close to the mixing flow channel (410).

6. The low-load stable operation and drainage recovery system of the low-pressure heater drain pump according to claim 1, It is characterized in that The connecting through hole (15) gradually slopes downward from an end away from the mixing flow channel (410) towards a direction close to the mixing flow channel (410).

7. The low-load stable operation and drainage recovery system of the low-pressure heater drain pump according to claim 1, It is characterized in that The mixing flow channel (410) is in a spiral shape along the vertical direction.

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