CN112963558A - Method for reducing double-gate valve faults of high-pressure steam-water system - Google Patents
Method for reducing double-gate valve faults of high-pressure steam-water system Download PDFInfo
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- CN112963558A CN112963558A CN202110325416.0A CN202110325416A CN112963558A CN 112963558 A CN112963558 A CN 112963558A CN 202110325416 A CN202110325416 A CN 202110325416A CN 112963558 A CN112963558 A CN 112963558A
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16K—VALVES; TAPS; COCKS; ACTUATING-FLOATS; DEVICES FOR VENTING OR AERATING
- F16K3/00—Gate valves or sliding valves, i.e. cut-off apparatus with closing members having a sliding movement along the seat for opening and closing
- F16K3/02—Gate valves or sliding valves, i.e. cut-off apparatus with closing members having a sliding movement along the seat for opening and closing with flat sealing faces; Packings therefor
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Abstract
The invention discloses a method for reducing the fault of a double-gate valve of a high-pressure steam-water system, relates to the technical field of high-pressure steam-water thermal systems, and aims to solve the problem that the double-gate valve of the high-pressure steam-water system cannot be normally opened frequently; the method comprises the steps that when water is fully discharged after the boiler is stopped, the water discharge valves are completely opened, and residual water in the pipeline is completely discharged; when the unit starts the front heating pipe, the double-gate valve is opened firstly, and accumulated water in the middle cavity of the double-gate valve is discharged; when the furnace is shut down for maintenance, the valve limit is checked again and readjusted; before ignition of the boiler, a cold state switch test is carried out on a double-gate valve of a water supply system, a pipeline water drain valve is opened to drain air, the double-gate valve is slightly opened, and the double-gate valve is immediately closed after water is introduced, and the operation is repeated discontinuously; when the boiler is in a cold state, the temperature of the feeding water is controlled to be below 150 ℃, and when the boiler starts a heating pipe, the air in the pipeline is ensured to be exhausted, so that the heating pipe time is reduced; the invention fundamentally avoids the problem that the double-gate valve cannot be normally opened due to faults.
Description
Technical Field
The invention relates to the technical field of high-pressure steam-water thermal systems, in particular to a method for reducing double-flashboard valve faults of a high-pressure steam-water system.
Background
The large-diameter valves of domestic high-pressure steam-water systems mostly adopt structures such as wedge-type single gate plates, wedge-type elastic gate plates, wedge-type double gate plates and parallel double gate plates. The wedge type elastic flashboard, the wedge type double flashboard and the parallel double flashboard are suitable for working conditions with larger calibers and larger differential pressure at two ends of the valve, wherein the wedge type double flashboard automatically adjusts the angle of the flashboard through the top core between the two movable flashboards and through the axial force exerted by the valve rod, compensates the processing error of a wedge angle, achieves a good two-way sealing effect, and is suitable for installing any pipeline position, so that the wedge type elastic flashboard, the wedge type double flashboard and the parallel double flashboard are widely applied, and at present, a plurality of unit boiler high-pressure water supply and high-pressure steam system.
The thermal generator set is generally large in capacity, mainly adopts unit system operation, and is low in temperature and small in differential pressure between the front and the back of a valve when the valve of the high-pressure steam-water system is started, so that faults are relatively few. However, for self-backup power plants in the industry, the capacity of a unit is relatively small, the unit mostly runs in a main pipe system, a boiler is sealed by bearing the pressure difference formed between a middle cavity and connecting pipelines at two ends simultaneously due to the excellent double-side sealing performance of the wedge-type double gate plates in the cold starting process of the boiler, fluid blocked in the middle cavity is synchronously raised by medium heat transfer in the system starting process, the fluid in the middle cavity is vaporized probably due to thermal expansion, the geometric progression of the pressure process is rapidly raised, the middle cavity of the valve is abnormally over-pressurized, pressure-bearing interfaces and related parts are damaged, an actuator over-moment alarm occurs, the valve cannot be normally opened, a valve rod is broken when the valve rod is serious, a gate plate frame is broken, and a support, a four-open ring and a valve body are deformed in different degrees, valve failure and scrapping. Most of the time, the above valve failure situation is forced to be taken out of the furnace.
The inventor summarizes and discovers from a large number of practical operation processes: the large-caliber double-gate valve of the high-pressure steam-water system is easy to break down frequently and is generated in the cold-state starting process of a boiler; in view of the above problems of repeatability and continuity of valve failures, great attention should be paid, and therefore, a method for reducing the failures of the dual gate valve of the high pressure steam-water system is urgently needed to solve the problem.
Disclosure of Invention
The invention aims to provide a method for reducing the faults of a double-gate valve of a high-pressure steam-water system, so as to solve the problem that the double-gate valve of the high-pressure steam-water system cannot be normally opened frequently.
In order to achieve the purpose, the invention provides the following technical scheme: a method of reducing high pressure steam water system double gate valve failures, comprising:
1) when the boiler is completely drained after being stopped, the drain valves on the water supply system are all opened, and the residual water in the pipeline is drained; when the unit is started and the pipe is warmed, the double-gate valve is opened firstly, and accumulated water in the middle cavity of the double-gate valve is discharged;
2) for the double-gate valve which runs on line, when the furnace is shut down for maintenance, the limit of the valve is checked again, the phenomenon of over-adjustment is found, and the limit of the valve is required to be adjusted again in time;
3) before ignition of the boiler, a cold state switch test is carried out on a double-gate valve of a water supply system, when a pipe is heated, a drain valve of the pipeline is completely opened, and the pipe is closed after air is exhausted; secondly, slightly opening the double-gate valve, feeding water into the boiler, immediately closing the boiler after water is fed, and intermittently repeating the switching operation in the process of rising the temperature of the fed water;
4) when the boiler is in a cold state, the temperature of the feeding water is controlled to be below 150 ℃.
Preferably, the double-gate valve does not require double-side sealing, and the outer edge of the valve seat at the inlet side or the gate at the inlet side is provided with a pressure relief hole to communicate the middle cavity of the double-gate valve with the pipeline at the inlet side.
Preferably, the double-gate valve is adjusted to be limited before being newly installed, and the moment action value when the sealing surface of the valve is normally contacted and leaves a factory is used as an adjusting basis.
Preferably, in the cold switching test, the switching operation is intermittently repeated at least twice.
Preferably, in the cold switch test, if the water level of the steam drum is difficult to control, the water level is controlled by opening the water drain valve.
Preferably, the temperature of the water supply is controlled below 150 ℃, and the water supply system high-pressure heater is temporarily stopped.
Preferably, when the boiler is used for heating the pipe, the pipe heating time is reduced as far as possible on the premise of ensuring that air in the pipeline is exhausted.
Compared with the prior art, the invention has the beneficial effects that:
according to the method for reducing the double-gate valve fault of the high-pressure steam-water system, the problem that the double-gate valve cannot be normally opened due to the fault is fundamentally solved by removing accumulated water in the cavity of the double-gate valve, adjusting the valve limit, performing a cold-state switch test, reducing the temperature of the feeding water and reducing the pipe heating time, a pressure-bearing interface and related parts cannot be damaged or deformed, and the condition of forced blowing-out treatment is avoided; the time wasted in fault removal can be reduced, so that the normal power generation of the blast furnace is ensured, the cost for maintaining or replacing parts can be reduced, and the service life of equipment is prolonged.
Drawings
FIG. 1 is a schematic diagram of the internal structure of a conventional double-gate valve;
fig. 2 is a schematic structural diagram of a double-gate valve and a drain valve on a pipeline of a conventional high-pressure steam system.
Detailed Description
Fig. 1 is a schematic diagram of an internal structure of a common double-gate valve in the market, and it can be seen from the diagram that a middle cavity exists between two gate plates, liquid is remained at the middle cavity, the valve with the double-gate plate structure simultaneously bears a pressure difference formed between the middle cavity and connecting pipelines at two ends to seal, when the temperature of a system rises, fluid blocked in the middle cavity is synchronously raised by medium heat transfer, the fluid in the middle cavity is possibly vaporized due to thermal expansion, so that the geometric progression of a pressure process is sharply raised, abnormal overpressure of the middle cavity of the valve occurs, a pressure-bearing interface and related parts are damaged, an actuator over-moment alarm occurs, the valve cannot be normally opened, a valve rod is broken when the valve rod is serious, a gate plate frame is broken, a support, a four-open ring and a valve body are deformed to different degrees, and the valve; the inventors therefore propose the present invention to thoroughly solve the above problems.
The invention discloses a method for reducing double-flashboard valve faults of a high-pressure steam-water system, which comprises the following steps:
1) when the boiler is completely drained after being stopped, all the drainage valves on the water supply system are opened, and the residual water in the pipeline is drained, wherein FIG. 2 shows the structural schematic of the double-gate valve and the drainage valve on the pipeline of the existing high-pressure steam system, four double-gate valves are arranged on the main pipeline in the figure, and a plurality of drainage valves are arranged below the main pipeline; when the unit is started and the pipe is warmed, the double-gate valve is opened firstly, and accumulated water in the middle cavity of the double-gate valve is discharged;
2) because the high-pressure water supply system of the unit operates by a main pipe system, when the boiler is started in a cold state, the differential pressure of the water supply system of the boiler is large, namely the moment borne by the valve is large, if the moment set during the adjustment of the valve closing limit is too large, the moment for opening the valve is too large after the water supply differential pressure is established, so that the valve cannot be normally opened; therefore, when the on-line operation double-gate valve is shut down for maintenance, the valve limit is checked again, the phenomenon of over-adjustment is found, and the valve limit is required to be adjusted again in time; in addition, the double-gate valve can be used for adjusting the position limitation of the valve before being newly installed, and if the double-gate valve is an electric valve, a temporary power supply can be connected; during adjustment, the normal contact of the sealing surface of the valve and the moment action value when the valve leaves a factory are taken as the adjustment basis, and if the deviation between the limiting adjustment position of the valve and the moment action value is overlarge, the valve is preferably connected with a manufacturer to be cooperatively solved.
3) Under the normal condition, the boiler is ignited after water is supplied to the boiler, the double-gate valve is in a closed state, the water level of a steam drum can be ensured due to the rising of water temperature, and when the double-gate valve needs to be opened for water supplement, the double-gate valve is not opened due to the fact that the middle cavity of the double-gate valve is often subjected to pressure building; in contrast, before ignition of the boiler, a cold-state switch test is carried out on a double-gate valve of a water supply system, and when a pipe is heated, a drain valve of the pipeline is completely opened, and the pipe is closed after air is exhausted; secondly, slightly opening the double-gate valve, feeding water into the boiler, immediately closing the boiler after water is fed, and intermittently repeating the switching operation in the process of raising the temperature of the fed water, preferably repeating the switching operation at least twice, so that the pressure build-up of the middle cavity can be effectively eliminated; in the process of feeding water to the boiler, the test can cause that the water level of the steam drum is high, which is not beneficial to ignition of the boiler (the normal water level of the steam drum is needed when the boiler is ignited), and if the water level of the steam drum is difficult to control, the water level can be controlled by opening a water drain valve;
4) when the boiler is in a cold state, the temperature of the feeding water is controlled to be below 150 ℃, and if the temperature of the water is difficult to control, the high-pressure heater of the water supply system can be considered to be temporarily stopped; in addition, the heating time can be strictly controlled during heating the boiler, as long as air in the steam-water pipeline is exhausted, the pipeline does not generate water impact, and the shorter the heating time is, the better the heating time is.
Under some service conditions, the double-gate valve does not require double-side sealing, then a pressure relief hole can be formed in the outer edge of the valve seat at the inlet side or the gate at the inlet side, the middle cavity of the double-gate valve is communicated with the pipeline at the inlet side, but the method can cause the double-gate valve to be not different from the single-gate valve and can only be used under the working condition that double-side sealing is not required.
Collecting fault data of an electric wedge type double-gate valve in the starting process of a boiler in the last two years of six high-pressure steam-water systems of the boiler in the south of the horse steel, wherein the normal starting only accounts for 63.64 percent of the total starting times, the starting fault times are as high as 36.36 percent, and 1 valve fault happens on average every 3 starting times;
after the method is adopted, data collection is carried out for half a year, and the valve does not have a failure that the valve cannot be opened again in the total 12 starting processes of the boiler, so that the technical problems are thoroughly solved, and the safe and stable operation of the boiler is guaranteed.
About 6 hours are needed before and after each valve processing to remove the fault and recover the operation, according to the fault rate of about 1/3 in the past, 4 faults can occur in half a year, and the economic effect produced in half a year is as follows: the net benefit 6 x 4 x 6 x 0.2 x 28.8 ten thousand yuan from multiple power generations (high pressure boilers typically generate 6 ten thousand kwh per hour with a profit of about 0.2 yuan per degree of electricity); the overhaul equipment cost is saved by 1.5 ten thousand yuan, the labor cost is saved by 3000 yuan, and the total cost is 28.8+1.5+0.3 which is 30.6 ten thousand yuan, so that the equipment safety can be ensured, the service life is effectively prolonged, and the like, and the effect is very considerable.
The above description is only for the preferred embodiment of the present invention, but the scope of the present invention is not limited thereto, and any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope of the present invention are also included in the scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope defined by the claims.
The present invention is not described in detail, but is known to those skilled in the art.
Claims (7)
1. A method for reducing double-gate valve faults of a high-pressure steam-water system is characterized by comprising the following steps:
1) when the boiler is completely drained after being stopped, the drain valves on the water supply system are all opened, and the residual water in the pipeline is drained; when the unit is started and the pipe is warmed, the double-gate valve is opened firstly, and accumulated water in the middle cavity of the double-gate valve is discharged;
2) for the double-gate valve which runs on line, when the furnace is shut down for maintenance, the limit of the valve is checked again, the phenomenon of over-adjustment is found, and the limit of the valve is required to be adjusted again in time;
3) before ignition of the boiler, a cold state switch test is carried out on a double-gate valve of a water supply system, when a pipe is heated, a drain valve of the pipeline is completely opened, and the pipe is closed after air is exhausted; secondly, slightly opening the double-gate valve, feeding water into the boiler, immediately closing the boiler after water is fed, and intermittently repeating the switching operation in the process of rising the temperature of the fed water;
4) when the boiler is in a cold state, the temperature of the feeding water is controlled to be below 150 ℃.
2. The method for reducing the failure of the double-gate valve of the high-pressure steam-water system according to claim 1, wherein the method comprises the following steps: the double-gate valve does not require double-side sealing, and the outer edge of the valve seat at the inlet side or the gate plate at the inlet side is provided with a pressure relief hole to communicate the middle cavity of the double-gate valve with the pipeline at the inlet side.
3. The method for reducing the failure of the double-gate valve of the high-pressure steam-water system according to claim 1, wherein the method comprises the following steps: and before the double-gate valve is newly installed, the valve is adjusted to be limited, and the moment action value when the sealing surface of the valve is normally contacted and leaves the factory is used as an adjusting basis.
4. The method for reducing the failure of the double-gate valve of the high-pressure steam-water system according to claim 1, wherein the method comprises the following steps: in the cold state switching test, the switching operation is intermittently repeated at least twice.
5. The method for reducing the failure of the double-gate valve of the high-pressure steam-water system according to claim 1, wherein the method comprises the following steps: in the cold state switch test, if the water level of the steam drum is difficult to control, the water level is controlled by opening the water drain valve.
6. The method for reducing the failure of the double-gate valve of the high-pressure steam-water system according to claim 1, wherein the method comprises the following steps: the temperature of the water supply is controlled to be below 150 ℃, and the method is realized by temporarily stopping the high-pressure heater of the water supply system.
7. The method for reducing the failure of the double-gate valve of the high-pressure steam-water system according to claim 1, wherein the method comprises the following steps: when the boiler is used for heating the pipe, the pipe heating time is reduced as far as possible on the premise of ensuring that the air in the pipeline is exhausted.
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| CN202110325416.0A CN112963558B (en) | 2021-03-26 | 2021-03-26 | Method for reducing double-flashboard valve fault of high-pressure steam-water system |
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| CN202110325416.0A CN112963558B (en) | 2021-03-26 | 2021-03-26 | Method for reducing double-flashboard valve fault of high-pressure steam-water system |
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Citations (6)
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| JPH1137313A (en) * | 1997-07-15 | 1999-02-12 | Tokyo Electric Power Co Inc:The | Double block piping for very low temperature |
| CN202884074U (en) * | 2012-09-11 | 2013-04-17 | 中国核电工程有限公司 | Non-active pressure balance system solving boiler effect of nuclear grade sluice valve |
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| CN204784806U (en) * | 2015-07-16 | 2015-11-18 | 苏州热工研究院有限公司 | Guide's formula gate valve |
| CN106015607A (en) * | 2016-07-12 | 2016-10-12 | 浙江挺宇流体设备股份有限公司 | Parallel double-gate-disc gate valve of center cavity bi-direction automatic pressure relieving structure |
| CN111578135A (en) * | 2020-06-12 | 2020-08-25 | 河北冀研能源科学技术研究院有限公司 | Gate valve middle cavity overvoltage protection device capable of achieving outward leakage |
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2021
- 2021-03-26 CN CN202110325416.0A patent/CN112963558B/en active Active
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH1137313A (en) * | 1997-07-15 | 1999-02-12 | Tokyo Electric Power Co Inc:The | Double block piping for very low temperature |
| CN202884074U (en) * | 2012-09-11 | 2013-04-17 | 中国核电工程有限公司 | Non-active pressure balance system solving boiler effect of nuclear grade sluice valve |
| CN203770701U (en) * | 2014-04-03 | 2014-08-13 | 中正科技阀门有限公司 | Anti-locking wedge-shaped single wedge disc gate valve for ultra supercritical state |
| CN204784806U (en) * | 2015-07-16 | 2015-11-18 | 苏州热工研究院有限公司 | Guide's formula gate valve |
| CN106015607A (en) * | 2016-07-12 | 2016-10-12 | 浙江挺宇流体设备股份有限公司 | Parallel double-gate-disc gate valve of center cavity bi-direction automatic pressure relieving structure |
| CN111578135A (en) * | 2020-06-12 | 2020-08-25 | 河北冀研能源科学技术研究院有限公司 | Gate valve middle cavity overvoltage protection device capable of achieving outward leakage |
Non-Patent Citations (1)
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| 包泳珂等: "CPR1000型核电机组辅助给水汽动泵蒸汽入口隔离阀开启故障研究", 《核动力工程》 * |
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