Boiler recirculation system

Abstract

The present disclosure relates to a boiler recirculation system comprising: a boiler assembly; the deaerator comprises a water outlet and a water inlet; two ends of the water outlet pipeline are respectively connected with the water outlet and the boiler assembly; two ends of the recirculation main path are respectively connected with the water outlet pipeline and the water inlet; the recirculation branch is in bypass connection with the recirculation main path in an openable and closable mode, and when the target load of the boiler assembly is lower than a load threshold value, water in the water outlet pipeline can enter the deaerator through the recirculation branch; the two adjusting valves are arranged on the recycling main path and the recycling branch path respectively, each adjusting valve comprises a movable valve element, a valve seat and a guide cage, the valve seat and the guide cage are annularly arranged on the outer side of the valve element and connected with each other, and guide ribs protruding inwards are arranged on the inner side of the guide cage in the extending direction of the guide cage at intervals; a plurality of bosses corresponding to the guide ribs are arranged on the valve element at intervals. The damage rate of a recirculation regulating valve of a boiler assembly is reduced, and the efficiency of a generator set is improved.

Description

Technical Field

[0001] This disclosure relates to the field of thermal power boiler circulation technology, and more specifically, to a boiler recirculation system. Background Technology

[0002] The recirculation control valve in a large boiler generator set is a crucial fluid control unit in a thermal power plant. During operation, the generator set places high demands on the regulating performance of the recirculation valve. Due to the large pressure difference across the valve, it operates under strong cavitation conditions for extended periods, which can easily lead to internal leakage, damaging internal components and rendering the valve unusable. This not only reduces the valve's lifespan but also affects the generator set's power generation efficiency, ultimately impacting the safe and economical operation of the power plant. Utility Model Content

[0003] The purpose of this disclosure is to provide a boiler recirculation system to address the problem that the vulnerability of recirculation control valves in boiler components affects generator set efficiency.

[0004] To achieve the above objectives, this disclosure provides a boiler recirculation system, comprising:

[0005] Boiler components;

[0006] A deaerator includes an outlet and an inlet;

[0007] The water outlet pipe is connected at both ends to the water outlet and the boiler assembly, respectively.

[0008] The main recirculation pipeline is connected at both ends to the outlet pipeline and the inlet, respectively.

[0009] A recirculation branch, closable and connectable to the main recirculation line, allows water in the outlet pipe to enter the deaerator when the target load of the boiler assembly is below the load threshold; and allows water in the outlet pipe to enter the deaerator when the target load of the boiler assembly is not below the load threshold.

[0010] Two regulating valves are respectively installed on the main recirculation line and the branch recirculation line. Each regulating valve includes a movable valve core, a valve seat and a guide cage that are arranged around the outside of the valve core and connected to each other. The inner side of the guide cage is provided with inwardly protruding guide ribs at intervals along the extension direction of the guide cage. The valve core is provided with a plurality of protrusions at intervals corresponding to the guide ribs.

[0011] Optionally, a sealing gasket is provided on the valve seat, and a sealing head is formed at the end of the valve core, with a sealing bevel formed on the sealing head that can fit with the sealing gasket.

[0012] Optionally, the sealing head may also have a first flow guiding slope, which is located below the sealing slope.

[0013] Optionally, the sealing gasket includes a metal sealing gasket and a rubber sealing gasket, wherein the metal sealing gasket is connected to the valve seat, the rubber sealing gasket is arranged in a ring inside the metal sealing gasket, and the sealing bevel can contact the rubber sealing gasket.

[0014] Optionally, a second guide slope is provided on the side of the boss near the sealing head.

[0015] Optionally, the bottom of the valve seat is connected to the outlet, and the top of the valve seat is connected to the inlet.

[0016] Optionally, an isolation valve is provided on the recirculation branch.

[0017] Optionally, there are two isolation valves, which are respectively located on both sides of the regulating valve.

[0018] Optionally, a three-way valve is provided on the main recirculation line, and the recirculation branch is connected to the main recirculation line through the three-way valve.

[0019] Optionally, a turbine feedwater pump is connected to the outlet pipeline, and the turbine feedwater pump is located upstream of the connection between the main recirculation pipeline and the outlet pipeline.

[0020] Through the above technical solution, different pipelines are used for flow regulation according to different target loads of the boiler components. When the target load is lower than the load threshold, the flow is regulated by the regulating valve on the recirculation branch to reduce erosion of the regulating valve on the main recirculation line, thereby extending the life of the regulating valve on the main recirculation line and reducing maintenance costs. In addition, the regulating valve, through the cooperation of the guide cage with guide ribs and the valve core with bosses, reduces the gap between the valve core and the guide cage, thereby reducing the liquid flow velocity in the regulating valve. This reduces the possibility of strong erosion of the regulating valve by water flow at the gap, effectively protecting the regulating valve, further extending its service life, reducing maintenance costs, and improving the efficiency of the generator set in the boiler component.

[0021] Other features and advantages of this disclosure will be described in detail in the following detailed description section. Attached Figure Description

[0022] The accompanying drawings are provided to further illustrate the present disclosure and form part of the specification. They are used together with the following detailed description to explain the present disclosure, but do not constitute a limitation thereof. In the drawings:

[0023] Figure 1This is a schematic diagram of a boiler recirculation system according to one embodiment of the present disclosure.

[0024] Figure 2 This is a schematic diagram of the water flow direction when the target load of the boiler components in a boiler recirculation system according to one embodiment of the present disclosure is lower than the load threshold.

[0025] Figure 3 This is a schematic diagram of the water flow direction in a boiler recirculation system according to one embodiment of the present disclosure when the target load of the boiler components is not lower than the load threshold.

[0026] Figure 4 This is a schematic diagram of a regulating valve in a boiler recirculation system according to one embodiment of the present disclosure.

[0027] Figure 5 This is a schematic diagram of the opening of a regulating valve in a boiler recirculation system according to one embodiment of the present disclosure.

[0028] Figure 6 This is a schematic diagram of the control valve being closed in a boiler recirculation system according to one embodiment of the present disclosure.

[0029] Explanation of reference numerals in the attached figures

[0030] 1-Boiler assembly; 2-Deaerator; 21-Outlet; 22-Inlet; 3-Outlet pipeline; 31-Turbine feedwater pump; 4-Main recirculation line; 41-Three-way valve; 5-Recirculation branch; 51-Isolation valve; 6-Regulating valve; 601-Inlet channel; 602-Outlet channel; 60-Valve core; 61-Valve seat; 611-Metal gasket; 612-Rubber gasket; 62-Guide cage; 621-Guide rib; 63-Boss; 631-Second guide slope; 64-Sealing head; 641-Sealing slope; 642-First guide slope. Detailed Implementation

[0031] The specific embodiments of this disclosure will be described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are for illustration and explanation only and are not intended to limit this disclosure.

[0032] In this disclosure, unless otherwise stated, directional terms such as "inner" and "outer" are defined in relation to the outline of the corresponding components. The terms "first," "second," etc., are used to distinguish different components and are not sequential or significant. Furthermore, in the following description, when referring to the accompanying drawings, unless otherwise explained, the same reference numerals in different drawings denote the same or similar elements.

[0033] According to one embodiment of this disclosure, such as Figures 1 to 6As shown, a boiler recirculation system is provided, including a boiler assembly 1, a deaerator 2, an outlet pipe 3, a main recirculation line 4, a branch recirculation line 5, and two regulating valves 6. The deaerator 2 includes an outlet 21 and an inlet 22. The two ends of the outlet pipe 3 are connected to the outlet 21 and the boiler assembly 1, respectively. The two ends of the main recirculation line 4 are connected to the outlet pipe 3 and the inlet 22, respectively. The branch recirculation line 5 is closable and bypasses the main recirculation line 4. When the target load of the boiler assembly 1 is lower than the load threshold, water in the outlet pipe 3 can enter the deaerator 2 through the branch recirculation line 5. When the target load of the boiler assembly 1 is not lower than the load threshold, water in the outlet pipe 3 can enter the deaerator 2 through the main recirculation line 4. Two regulating valves 6 can be respectively installed on the main recirculation line 4 and the branch recirculation line 5. The regulating valve 6 includes a movable valve core 60, a valve seat 61 and a guide cage 62 that are arranged around the outside of the valve core 60 and connected to each other. The inner side of the guide cage 62 is provided with inwardly protruding guide ribs 621 at intervals along the extension direction of the guide cage 62. The valve core 60 is provided with a plurality of protrusions 63 corresponding to the guide ribs 621 at intervals.

[0034] Through the above technical solution, different pipelines are used to regulate the flow rate for different target loads of boiler assembly 1. When the target load is lower than the load threshold, the regulating valve 6 on the recirculation branch 5 is used to reduce the scouring of the regulating valve 6 on the recirculation main line 4, thereby extending the life of the regulating valve 6 on the recirculation main line 4 and reducing maintenance costs. In addition, the regulating valve 6, through the cooperation of the guide cage 62 with guide ribs 621 and the valve core 60 with protrusions 63, reduces the gap between the valve core 60 and the guide cage 62, thereby reducing the liquid flow velocity in the regulating valve 6 and reducing the possibility of strong scouring of the regulating valve 6 by water flow at the gap, effectively protecting the regulating valve 6. This further extends the service life of the regulating valve 6, reduces maintenance costs, and improves the efficiency of the generator set in boiler assembly 1.

[0035] It should be noted that the load threshold can be 200MW, or it can be set to other values ​​as needed; this disclosure does not limit this. Specifically, when the target load of boiler assembly 1 is lower than the load threshold, the regulating valve 6 on the main recirculation line 4 can be closed, and the regulating valve 6 on the recirculation branch line 5 can be opened. At this time, the water flow direction is as follows: Figure 2 As shown, this allows water in outlet pipe 3 to enter deaerator 2 through recirculation branch 5. When the target load of boiler assembly 1 is not lower than the load threshold, regulating valve 6 on recirculation branch 5 can be closed and regulating valve 6 on recirculation main line 4 can be opened. At this time, the water flow direction is as follows. Figure 3As shown, this allows water in the outlet pipe 3 to enter the deaerator 2 through the recirculation main pipe 4. Here, when the target load of boiler assembly 1 is not lower than the load threshold, a load upper limit greater than the threshold can also be set. Taking a load threshold of 200MW as an example, the load upper limit is 300MW. When the target load is not lower than 200MW and not higher than 300MW, the regulating valve 6 on the recirculation branch 5 can be closed, and the regulating valve 6 on the recirculation main pipe 4 can be opened. At this time, the water flow direction is as follows... Figure 3 As shown, water in the outlet pipe 3 can enter the deaerator 2 through the recirculation main line 4. When the target load is higher than 300MW, the regulating valves 6 on the recirculation main line 4 and the recirculation branch line 5 can be closed at the same time so that the boiler system does not participate in the recirculation operation. This disclosure does not limit this.

[0036] Furthermore, such as Figures 1 to 4 As shown, the bottom of valve seat 61 can communicate with outlet 21, and the top of valve seat 61 can communicate with inlet 22. The regulating valve 6 can include an inlet channel 601 and an outlet channel 602. Inlet channel 601 can be connected to the bottom of valve seat 61, and outlet channel 602 can be connected to the top of valve seat 61. In this way, the regulating valve 6 has a low-inlet, high-outlet connection (the inlet end of the regulating valve 6 is lower than the outlet end). When the valve core 60 is at a low opening, it is less likely to malfunction due to reverse flow, thus improving regulation stability and increasing regulation accuracy.

[0037] According to one embodiment of this disclosure, such as Figures 1 to 3 As shown, an isolation valve 51 can be installed on the recirculation branch 5. When the recirculation branch needs maintenance, the connection between the recirculation branch 5 and the main recirculation line 4 can be disconnected by the isolation valve 51. Maintenance of the recirculation branch 5 and the regulating valve 6 installed on the recirculation branch 5 can be carried out without affecting other parts of the boiler system, achieving system shutdown during maintenance of the recirculation branch 5. Specifically, there can be two isolation valves 51, which are respectively installed on both sides of the regulating valve 6. In this way, when the regulating valve 6 needs to be replaced, the part between the two isolation valves 51 can be isolated by the isolation valves 51 on both sides, thereby removing the regulating valve 6 for replacement and maintenance. At the same time, it can also prevent liquid from flowing out of the recirculation branch 5 when the regulating valve 6 is removed.

[0038] According to one embodiment of this disclosure, such as Figures 1 to 3 As shown, a three-way valve 41 can be installed on the main recirculation line 4, and the recirculation branch line 5 can be connected to the main recirculation line 4 through the three-way valve 41. When it is necessary to connect the recirculation branch line 5 and close the main recirculation line 4, or connect the main recirculation line 4 and close the recirculation branch line 5, the opening and closing of the recirculation branch line 5 and the main recirculation line 4 can be adjusted by adjusting the three-way valve 41, or the opening and closing of the corresponding pipeline can be adjusted by adjusting the regulating valve 6 on the corresponding pipeline as mentioned above. This disclosure does not limit this.

[0039] According to one embodiment of this disclosure, such as Figures 1 to 3 As shown, a turbine feedwater pump 31 can be connected to the outlet pipe 3. The turbine feedwater pump 31 is located upstream of the connection between the recirculation main line 4 and the outlet pipe 3. By adjusting the power of the turbine feedwater pump 31, the recirculation water flow pressure can be ensured to be stable, thus preventing pump cavitation.

[0040] According to one embodiment of this disclosure, such as Figures 4 to 6 As shown, a sealing gasket is provided around the valve seat 61, and a sealing head 64 is formed at the end of the valve core 60. A sealing bevel 64 is formed on the sealing head 64, which can fit against the sealing gasket. It should be noted that when the regulating valve 6 is open, the sealing bevel 641 is spaced from the sealing gasket, allowing water to pass through the gap and move along the corresponding recirculation main line 4 or recirculation branch line 5. When the regulating valve 6 is closed, the sealing bevel 641 fits and is pressed tightly against the sealing gasket. Figure 6 As shown, the water flow on both sides of the valve seat 61 is isolated. The part of the sealing head 64 that fits with the sealing gasket is an inclined surface. The inclined surface seal can disperse the medium pressure and reduce local stress concentration on the sealing surface. At the same time, when the regulating valve 6 is opened, the sealing inclined surface 641 can also play a certain guiding role, avoiding strong scouring of the sealing inclined surface 641 and the sealing gasket by the water flow in the gap, effectively protecting the valve core 60 and the valve seat 61, and improving the service life of the regulating valve 6.

[0041] In addition, the guide ribs 621 can be set one-to-one with the bosses 63, so that when the regulating valve 6 is opened, such as Figure 5 As shown, at this time, the sealing head 64 moves upward and a gap for water to enter is formed between it and the sealing gasket. The boss 63 also moves upward accordingly until the boss 63 is misaligned with the corresponding guide rib 621 in the vertical direction, so that the boss 63 and the guide rib 621 form a gap in the vertical direction. However, the gap formed by the boss 63 and the guide rib 621 in the vertical direction is smaller than the gap formed by the sealing head 64 and the sealing gasket. Therefore, after the water enters the regulating valve 6, while ensuring the flow rate, the water flow velocity can be further slowed down when the boss 63 and the guide rib 621 form a gap in the vertical direction, thereby reducing the flushing effect, further protecting the regulating valve 6, and extending the service life of the regulating valve 6. Of course, the guide ribs 621 can be set in a non-one-to-one correspondence with the bosses 63. For example, two guide ribs 621 can correspond to one boss 63. Since there is a gap between the guide ribs 621 and the bosses 63 in the horizontal direction, even after the sealing slope 641 is removed from the sealing gasket, there may still be a situation where the guide ribs 621 and the bosses 63 are still corresponding in the horizontal direction. At this time, the water flow can also flow directly to the water outlet channel 602 through the gap between the guide ribs 621 and the bosses 63 in the horizontal direction. This disclosure does not limit this.

[0042] Furthermore, such as Figure 5 and Figure 6 As shown, a first guide slope 642 is also formed on the sealing head 64, which is located below the sealing slope 641. The first guide slope 642 can guide the medium to pass smoothly through the valve seat 61, reduce turbulence and eddies, and prevent high-speed medium from directly impacting the sealing surface. This reduces the impact of water flow at the gap on the sealing slope 641 and the sealing gasket, effectively protecting the valve core 60 and the valve seat 61, and extending the service life of the regulating valve 6. In addition, a second guide slope 631 can also be provided on the side of the boss 63 near the sealing head 64 to guide the medium to move in the guide cage 62. This can also reduce turbulence and eddies, and reduce the impact of water flow at the gap on the boss 63 and the guide rib 621, thereby extending the service life of the regulating valve 6. The second guide slope 631 can also guide the medium to flush the gap of the guide rib 621, preventing jamming caused by particle deposition.

[0043] According to one embodiment of this disclosure, such as Figure 5 and Figure 6 As shown, the sealing gasket may also include a metal sealing gasket 611 and a rubber sealing gasket 612. The metal sealing gasket 611 is connected to the valve seat 61, and the rubber sealing gasket 612 is arranged around the inner side of the metal sealing gasket 611. The sealing bevel 641 can contact the rubber sealing gasket 612. The composite seal of rubber and metal provides a better sealing effect. The metal sealing gasket 611 can withstand the main seal under high temperature and high pressure, while the rubber sealing gasket 612 is elastic and can better fit the sealing head 64. Simultaneously, due to the elasticity of the rubber sealing gasket 612, it can also compensate for the microscopic wear between the sealing head 64 and the valve seat 61 caused by long-term use, extending the life of the regulating valve 6 while providing zero-leakage assurance.

[0044] The preferred embodiments of this disclosure have been described in detail above with reference to the accompanying drawings. However, this disclosure is not limited to the specific details of the above embodiments. Within the scope of the technical concept of this disclosure, various simple modifications can be made to the technical solutions of this disclosure, and these simple modifications all fall within the protection scope of this disclosure.

[0045] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, this disclosure will not describe the various possible combinations separately.

[0046] Furthermore, various different embodiments of this disclosure can be combined in any way, as long as they do not violate the spirit of this disclosure, they should also be regarded as the content disclosed in this disclosure.

Claims

1. A boiler recirculation system, characterized in that, include: Boiler components; A deaerator includes an outlet and an inlet; The water outlet pipe is connected at both ends to the water outlet and the boiler assembly, respectively. The main recirculation pipeline is connected at both ends to the outlet pipeline and the inlet, respectively. The recirculation branch is closable and can be connected to the main recirculation line. When the target load of the boiler assembly is lower than the load threshold, water in the outlet pipe can enter the deaerator through the recirculation branch. When the target load of the boiler assembly is not lower than the load threshold, water in the outlet pipe can enter the deaerator through the main recirculation line. and Two regulating valves are respectively installed on the main recirculation line and the branch recirculation line. Each regulating valve includes a movable valve core, a valve seat and a guide cage that are arranged around the outside of the valve core and connected to each other. The inner side of the guide cage is provided with inwardly protruding guide ribs at intervals along the extension direction of the guide cage. The valve core is provided with a plurality of protrusions at intervals corresponding to the guide ribs.

2. The boiler recirculation system according to claim 1, characterized in that, The valve seat is provided with a sealing gasket, and the end of the valve core is formed with a sealing head, and the sealing head is formed with a sealing bevel that can fit with the sealing gasket.

3. The boiler recirculation system according to claim 2, characterized in that, The sealing head also has a first flow guiding slope, which is located below the sealing slope.

4. The boiler recirculation system according to claim 2, characterized in that, The sealing gasket includes a metal sealing gasket and a rubber sealing gasket, wherein the metal sealing gasket is connected to the valve seat, the rubber sealing gasket is arranged in a ring inside the metal sealing gasket, and the sealing bevel can contact the rubber sealing gasket.

5. The boiler recirculation system according to claim 2, characterized in that, A second guide slope is provided on the side of the boss near the sealing head.

6. The boiler recirculation system according to claim 1, characterized in that, The bottom of the valve seat is connected to the outlet, and the top of the valve seat is connected to the inlet.

7. The boiler recirculation system according to claim 1, characterized in that, An isolation valve is installed on the recirculation branch.

8. The boiler recirculation system according to claim 7, characterized in that, There are two isolation valves, which are respectively located on both sides of the regulating valve.

9. The boiler recirculation system according to claim 1, characterized in that, A three-way valve is installed on the main recirculation line, and the recirculation branch is connected to the main recirculation line through the three-way valve.

10. The boiler recirculation system according to claim 1, characterized in that, A turbine feedwater pump is connected to the outlet pipeline, and the turbine feedwater pump is located upstream of the connection between the main recirculation pipeline and the outlet pipeline.

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