CN113639935A - Vacuum tightness detection system and method for condensing steam turbine unit - Google Patents
Vacuum tightness detection system and method for condensing steam turbine unit Download PDFInfo
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Abstract
The invention provides a vacuum tightness detection system and a method of a condensing steam turbine unit, wherein in a vacuum pumping device, the gas flow value exhausted by a gas-water separator is measured in real time, and the influence of the moisture, the water level and the water temperature change of the gas-water separator is eliminated, so that the accurate gas flow value exhausted by the gas-water separator is obtained; determining the air amount leaked into the back of the outlet valve through tests, and subtracting the air amount leaked into the back of the outlet valve from the real-time measured gas flow value of the exhaust gas to obtain the air leakage value in front of the outlet valve; establishing a relation curve between the air leakage value before valve pumping and the vacuum descending speed value through a vacuum tightness test; and searching a curve according to the pre-valve air leakage value measured and calculated in real time to obtain a vacuum descending speed value. The invention can realize the calculation of vacuum tightness data only by monitoring parameters such as gas flow discharged into the atmosphere without frequently testing during the normal operation of the condensing steam turbine set.
Description
Technical Field
The invention relates to the technical field of thermal detection, in particular to a vacuum tightness detection system and method of a condensing steam turbine unit.
Background
The vacuum of a condensing steam turbine set is one of important monitoring parameters of a power plant, and the vacuum change of a condenser has great influence on the safe and economic operation of a steam turbine.
The operation tests of some units show that the steam consumption of a steam turbine can be increased by 1.5-2.5% and the coal consumption of a generator can be increased by 0.25% when the vacuum of a condenser is reduced by 1kPa, so that the efficiency of the unit is reduced. In addition, air leaks into the condensate and can make the water dissolved oxygen that condenses unqualified, influences the safe operation of unit.
In order to maintain the condenser vacuum, in addition to cooling the steam discharged into the condenser with sufficient circulating cooling water, a vacuum-pumping device (e.g., a vacuum pump) is provided to pump out non-condensable gases (mainly leaked air) from the condenser. The extracted gas is a mixture of water vapor and non-condensable gas, and the gas is separated by a gas-water separator and discharged into the atmosphere. The vacuum pump takes a certain time to pump out non-condensing gas, and when air continuously leaks into the condenser, even if the vacuum pump continuously operates, the vacuum still has a certain degree of decline when comparing no air leaks, and the more the air that leaks into, the more the vacuum descends. When other conditions are basically unchanged and the quantity of the noncondensable gas extracted by the vacuum pump and the quantity of the air leaking into the condenser are balanced, the vacuum value is stabilized within a certain range.
The condenser vacuum value is related to not only the amount of air leaking into the condenser, but also the amount of circulating cooling water in the condenser, the heat load of the condenser, and the like. Therefore, the amount of air leaking into the condenser cannot be directly determined by the change in the vacuum value, and is generally quantitatively analyzed by a vacuum tightness test method. According to the strict test regulation of a vacuum system of DL/T932-2019 'guide rule for operation and maintenance of condenser and vacuum system' 5.2, when a unit normally operates, a strict test is carried out once a month; the load of the test time group is above 80% of rated load; and closing an air exhaust outlet valve of the condenser, stopping running the air exhaust equipment, starting recording the vacuum value after 30 seconds, recording for 8 minutes, and calculating the vacuum reduction speed by taking the vacuum reduction value within 5 minutes. For the unit with the capacity more than 100MW, the vacuum dropping speed is not more than 270Pa/min, and the unit is qualified.
The conventional vacuum tightness test has large workload and certain risk. In the test process, if the vacuum drops too fast and the vacuum pump is not started successfully, the vacuum too low unit is tripped. Therefore, the research on a simpler and more reliable vacuum tightness detection method is a technical problem to be solved urgently by those skilled in the art.
In view of the above, the present invention provides a system and a method for detecting vacuum tightness of a condensing steam turbine set.
Disclosure of Invention
The invention aims to provide a system and a method for detecting the vacuum tightness of a condensing steam turbine unit, which can automatically and continuously monitor the vacuum tightness of the condensing steam turbine unit, find and process abnormity in time and improve the economical efficiency and safety of the operation of the condensing steam turbine unit.
In order to achieve the purpose, the invention is realized by the following technical scheme:
the utility model provides a condensing steam turbine's vacuum tightness detecting system, is connected with evacuation equipment through exhaust duct including setting up the condenser in condensing steam turbine, the condenser, is equipped with the outlet valve on the exhaust duct, is equipped with deareator on the evacuation equipment, and its characterized in that, this detecting system still includes:
the exhaust gas quantity measuring unit is used for measuring and displaying the gas flow value exhausted by the gas-water separator; after the outlet valve is opened and the vacuumizing equipment is started, the measured value of the exhaust amount measuring unit is recorded as an original measured value; and the exhaust gas volume correction unit is used for correcting the original measured value according to the environmental parameters of the gas-water separator and recording the corrected value as an exhaust gas volume correction value.
And the post-valve air leakage quantity storage and recording unit is used for storing and recording a post-valve air leakage quantity value, and the post-valve air leakage quantity value is a measured value of the air discharge quantity measuring unit after the outlet valve is closed and the vacuumizing device is started.
And the post-valve air leakage correction unit is used for correcting the post-valve air leakage according to the atmospheric temperature and humidity parameters in the preset range of the outlet valve to obtain the post-valve air leakage after the moisture is removed, and recording the post-valve air leakage as a post-valve air leakage correction value.
And the calculation and display unit of the air leakage quantity before the valve is used for calculating and displaying the air leakage quantity value before the valve, wherein the air leakage quantity value before the valve is the difference value of the corrected value of the air displacement and the corrected value of the air leakage quantity after the valve.
The relation curve storage and recording unit is used for storing and recording the relation between the air leakage quantity before the valve and the vacuum descending speed; the relationship between the air leakage quantity before the valve and the vacuum descending speed is as follows: and (3) a corresponding relation curve between the air leakage value before the valve and the vacuum descending speed value measured in the corresponding vacuum tightness experiment.
And the vacuum descent speed display unit is used for calculating the before-valve air leakage value displayed by the display unit in real time according to the before-valve air leakage, and obtaining and displaying the corresponding vacuum descent speed value by searching the relation between the before-valve air leakage and the vacuum descent speed.
Further, the exhaust gas amount correction means includes:
and the exhaust temperature measuring module is used for measuring the gas temperature when the gas-water separator exhausts.
And the exhaust humidity measuring module is used for measuring the gas humidity when the gas-water separator exhausts.
And the exhaust pressure measuring module is used for measuring the gas pressure when the gas-water separator exhausts.
And the first exhaust gas volume correction module is used for correcting the original measured value according to the gas temperature, humidity and pressure measured by the exhaust temperature measurement module, the exhaust humidity measurement module and the exhaust pressure measurement module, calculating to obtain the original measured value after water vapor is removed, and recording the original measured value as a first gas flow volume correction value.
Further, the exhaust gas amount correction unit further includes:
and the water level measuring module of the gas-water separator is used for measuring the water level value of the gas-water separator.
And the second exhaust gas quantity correcting module is used for calculating the variation of the gas flow quantity value caused by the water level variation according to the water level value of the gas-water separator, and correcting the first gas flow quantity correcting value according to the variation, and recording the first gas flow quantity correcting value as a second gas flow quantity correcting value.
Further, the exhaust gas amount correction unit further includes:
and the water temperature measuring module of the gas-water separator is used for measuring the water temperature value of the gas-water separator.
And the exhaust third correction module is used for calculating the variation of the gas flow value caused by the water temperature variation according to the water temperature value of the gas-water separator, and correcting the gas flow second correction value according to the variation, and recording the second correction value as the exhaust correction value.
Further, still include:
and the alarm unit is used for giving an alarm when the current vacuum descending speed value reaches a preset alarm value.
Correspondingly, the invention also discloses a vacuum tightness detection method of the condensing steam turbine unit, which comprises the following steps:
s1: after the outlet valve is opened and the vacuumizing equipment is started, measuring and displaying the gas flow value exhausted by the gas-water separator, and recording the gas flow value as an original measured value;
s2: correcting the original measured value according to the environmental parameters of the gas-water separator, and recording as an exhaust gas volume correction value;
s3: after the outlet valve is closed and the vacuumizing equipment is started, measuring and displaying the gas flow value exhausted by the gas-water separator, and taking the gas flow value as the gas leakage value after the valve;
s4: correcting the post-valve air leakage according to the atmospheric temperature and humidity parameters in the preset range of the outlet valve to obtain the post-valve air leakage after the moisture is removed, and recording the post-valve air leakage as a corrected value of the post-valve air leakage;
s5: through the test, establishing a corresponding relation curve between the air leakage amount before the valve and the vacuum descending speed value in the vacuum tightness test;
s6: measuring and calculating in real time to obtain an exhaust volume correction value and a post-valve air leakage correction value, and subtracting the post-valve air leakage correction value from the exhaust volume correction value to obtain a real-time variable pre-valve air leakage value;
s7: and obtaining the vacuum descending speed value which changes in real time by searching a corresponding relation curve between the air leakage amount before the valve and the vacuum descending speed value in the vacuum tightness test.
Further, the step S2 includes:
and measuring the gas temperature, humidity and pressure when the gas-water separator exhausts, correcting the original measured value according to the measured gas temperature value, humidity value and pressure value, calculating to obtain the original measured value after removing water vapor, and recording as a first corrected value of the gas flow.
Further, the step S2 further includes:
measuring the water level value and the water temperature value of the gas-water separator;
calculating the variation of the gas flow value caused by the water level variation according to the water level value of the gas-water separator, and accordingly correcting the first correction value of the gas flow, and recording the first correction value as a second correction value of the gas flow;
and calculating the variation of the gas flow value caused by the water temperature variation according to the water temperature value of the gas-water separator, and correcting a second corrected gas flow value according to the variation of the water temperature value, wherein the second corrected gas flow value is recorded as an exhaust gas amount corrected value.
Further, the step S5 specifically includes the following steps:
s5.1: the method comprises the following steps of operating a condensing steam turbine set according to a working condition required by a vacuum tightness test, recording a gas flow value exhausted by a gas-water separator and subtracting a gas leakage value after a valve before the test to obtain a gas leakage value before the valve, then performing the vacuum tightness test, and recording a test result, namely a vacuum descending speed value after the test to obtain the gas leakage value before the valve and the vacuum descending speed value during the test; and recovering the condensing steam turbine set to the normal operation condition before the test.
S5.2: leaking air with a preset flow into the condenser, and obtaining the before-valve air leakage value and the vacuum descending value in the test according to the method of the step S5.1 after the vacuum value and the measured value of the exhaust flow of the gas-water separator are stable; and recovering the condensing steam turbine set to the normal operation condition before the test.
S5.3: and (5) changing the air amount leaking into the condenser according to the method of the step S5.2, and carrying out a plurality of tests to obtain a plurality of pairs of data corresponding to the air leakage value before the valve and the vacuum descending speed value.
S5.4: if the test result of the vacuum tightness test is unqualified, the leakage point is searched and processed, and then the test is carried out again until the test is qualified, so that the air leakage value before the valve and the vacuum descending speed value after the vacuum tightness test is qualified are obtained.
S5.5: and (5) sorting and fitting the before-valve air leakage quantity value and the vacuum descending speed value obtained in the steps S5.1-S5.4 to obtain a corresponding relation curve between the before-valve air leakage quantity and the vacuum descending speed value in the vacuum tightness test.
Further, step S7 is followed by:
s8: and alarming when the vacuum descending speed value reaches a preset alarm value.
Compared with the prior art, the invention has the beneficial effects that: the invention provides a vacuum tightness detection system and a method of a condensing steam turbine unit, wherein in a vacuum pumping device, the gas flow value exhausted by a gas-water separator is measured in real time, and the influence of the moisture, the water level and the water temperature change of the gas-water separator is eliminated, so that the accurate gas flow value exhausted by the gas-water separator is obtained; determining the air amount leaked into the back of the outlet valve through tests, and subtracting the air amount leaked into the back of the outlet valve from the real-time measured gas flow value of the exhaust gas to obtain the air leakage value in front of the outlet valve; establishing a relation curve between the air leakage value before valve pumping and the vacuum descending speed value through a vacuum tightness test; and searching a curve according to the pre-valve air leakage value measured and calculated in real time to obtain a vacuum descending speed value. The invention can realize the calculation of vacuum tightness data only by monitoring parameters such as gas flow discharged into the atmosphere without frequently testing during the normal operation of the condensing steam turbine set.
The invention can automatically detect and calculate the exhaust gas flow value of the gas-water separator of the vacuumizing equipment of the condensing steam turbine unit in real time, indirectly calculates the tightness of the vacuum system according to the exhaust gas flow value, has less workload and higher safety than the manual vacuum tightness test which is carried out regularly, can realize the continuous monitoring of the vacuum tightness of the condensing steam turbine unit, finds abnormality in time for processing, and improves the running economy and safety of the unit.
Therefore, compared with the prior art, the invention has prominent substantive features and remarkable progress, and the beneficial effects of the implementation are also obvious.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the provided drawings without creative efforts.
FIG. 1 is a system block diagram of the present invention;
FIG. 2 is a flow chart of the method of the present invention.
In the figure, 1 is an exhaust gas amount measuring unit; 2 is an exhaust amount correcting means; 3, a post-valve air leakage storage and recording unit; 4, a post-valve air leakage correction unit; 5, a calculation and display unit for air leakage before the valve; 6 is a relation curve storage and recording unit; 7 is a vacuum descending speed display unit; 8 is an alarm unit; 21 is an exhaust temperature measuring module; 22 is an exhaust humidity measuring module; an exhaust pressure measuring module 23; 24 is a water level measuring module of the gas-water separator; 25 is a water temperature measuring module of the gas-water separator; 26 is an exhaust gas first correction module; 27 is an exhaust gas second correction module 27; and 28 is an exhaust gas third correction module.
Detailed Description
The following description of the embodiments of the present invention will be made with reference to the accompanying drawings.
The first embodiment is as follows:
the embodiment provides a condensing steam turbine unit's tight nature in vacuum detecting system, is equipped with the condenser in the condensing steam turbine unit, and the condenser is connected with evacuation equipment through exhaust duct, is equipped with the outlet valve on the exhaust duct, is equipped with the deareator on the evacuation equipment.
As shown in fig. 1, the vacuum tightness detection system includes: the device comprises an exhaust gas quantity measuring unit 1, an exhaust gas quantity correcting unit 2, a post-valve air leakage quantity storage and recording unit 3, a post-valve air leakage quantity correcting unit 4, a pre-valve air leakage quantity calculation and display unit 5, a relation curve storage and recording unit 6, a vacuum descending speed display unit 7 and an alarm unit 8.
The exhaust gas measuring unit 1 is used for measuring and displaying a gas flow value exhausted by the gas-water separator; wherein, the measured value of the exhaust gas amount measuring unit after the outlet valve is opened and the vacuum-pumping device is started is recorded as the original measured value.
And the exhaust gas volume correction unit 2 is used for correcting the original measured value according to the environmental parameters of the gas-water separator and recording the corrected value as an exhaust gas volume correction value.
The exhaust gas amount correction means 2 includes:
and the exhaust temperature measuring module 21 is used for measuring the gas temperature of the exhaust gas of the gas-water separator.
And the exhaust humidity measuring module 22 is used for measuring the gas humidity of the exhaust gas of the gas-water separator.
And the exhaust pressure measuring module 23 is used for measuring the gas pressure of the gas discharged by the gas-water separator.
And the water level measuring module 24 of the gas-water separator is used for measuring the water level value of the gas-water separator.
And the water temperature measuring module 25 of the gas-water separator is used for measuring the water temperature value of the gas-water separator.
And the exhaust gas first correction module 26 is configured to correct the original measured value according to the gas temperature, humidity, and pressure measured by the exhaust gas temperature measurement module 21, the exhaust gas humidity measurement module 22, and the exhaust gas pressure measurement module 23, calculate to obtain the original measured value from which water vapor is removed, and record the original measured value as a gas flow first correction value.
It should be noted that the gas discharged into the atmosphere is separated by the gas-water separator, and contains a part of water vapor, and after the part of water vapor is removed, the main component contained in the gas is the non-condensable part, namely the air leaking into the condenser. It can be understood that the air leaking into the condenser also contains water vapor, but the water vapor is condensed into water after entering the condenser, the vacuum tightness test result cannot be influenced, and what really influences the vacuum tightness test result is the non-condensed part in the air leaking into the condenser. The steam contained in the exhaust gas is a part extracted from the condenser and a part generated in water of the steam-water separator, and after the steam is removed, a first corrected value of the gas flow obtained by correction and a vacuum descending speed value obtained by performing a vacuum tightness test have a relatively accurate corresponding relation. The calculation of the content of water vapor in air according to the humidity, temperature and pressure of the air belongs to the known technology and is not described in detail.
And the second exhaust gas flow rate correction module 27 is used for calculating the variation of the gas flow rate value caused by the water level variation according to the water level value of the gas-water separator, and correcting the first gas flow rate correction value according to the variation, wherein the first gas flow rate correction value is recorded as a second gas flow rate correction value.
It will be appreciated that the water level of the gas-water separator is not constant, and that the water level will drop if the water level is present, and that the space above the water level of the separator will increase as the water level drops; when water is supplemented to the gas-water separator, the space above the water surface of the gas-water separator is reduced due to the rising of the water level, and the flow value of the exhausted gas is changed. Therefore, the elimination of the change of the exhaust flow rate caused by the water level change can make the correspondence between the flow rate value and the vacuum drop rate value more accurate. Such as: when the water level variation is known to be X m/S and the sectional area of the gas-water separator is known to be S square meters, the variation of the exhaust flow rate due to the water level variation is: XS cubic meters per second.
And the exhaust third correction module 28 is used for calculating the variation of the gas flow value caused by the water temperature variation according to the water temperature value of the gas-water separator, and correcting the gas flow second correction value according to the variation, wherein the variation is recorded as the exhaust correction value.
It can be understood that, at a certain atmospheric pressure, when the water temperature of the gas-water separator is increased or decreased, the amount of air dissolved in the water is also changed, which in turn causes a change in the amount of air discharged into the atmosphere. Because the outlet of the gas-water separator is directly discharged into the atmosphere, the standard atmospheric pressure can be taken as the pressure of the separator during calculation, and the exhaust pressure value can also be taken as the pressure of the gas-water separator. Setting the water temperature of the last second as t ℃, and looking up a table to obtain the corresponding air content in the water under the corresponding atmospheric pressure as A%; the current water temperature is T ℃, and the corresponding air content in the water is B%; if the water level in the last second is X meters, the current water level is Y meters, and the sectional area of the gas-water separator is S square meters, the influence value of the change of the air amount in the water caused by the change of the water temperature and the water level on the exhaust flow rate value is as follows: (B% × S-A% × X S) cubic meters per second.
And the post-valve air leakage storage and recording unit 3 is used for storing and recording a post-valve air leakage value, and the post-valve air leakage value is a measured value of the air discharge measuring unit after the outlet valve is closed and the vacuumizing device is started.
In specific implementation, the flow value of the exhaust gas is recorded after being stabilized for a period of time.
And the post-valve air leakage correction unit 4 is used for correcting the post-valve air leakage according to the atmospheric temperature and humidity parameters in the preset range of the outlet valve to obtain the post-valve air leakage after the moisture is removed, and recording the post-valve air leakage as a post-valve air leakage correction value.
Of course, the atmospheric pressure value near the air extraction valve can be measured in real time, and the water content in the air can be calculated more accurately according to the parameters of atmospheric pressure, temperature, humidity and the like measured in real time. However, atmospheric pressure changes over the year at the same site
The range is smaller, if the atmospheric pressure gauge is not installed, the average atmospheric pressure value of the place can be selected for calculation, and the influence on the calculation result is smaller.
And the pre-valve air leakage calculation and display unit 5 is used for calculating and displaying a pre-valve air leakage value, wherein the pre-valve air leakage value is a difference value between the corrected value of the air displacement and the corrected value of the post-valve air leakage.
The relation curve storage and recording unit 6 is used for storing and recording the relation between the air leakage quantity before the valve and the vacuum descending speed; the relationship between the air leakage quantity before the valve and the vacuum descending speed is as follows: and (3) a corresponding relation curve between the air leakage value before the valve and the vacuum descending speed value measured in the corresponding vacuum tightness experiment. The curve is a one-to-one correspondence relation curve between different pre-valve air leakage values and vacuum descending values determined and fitted through a test method.
And the vacuum descent speed display unit 7 is used for calculating the before-valve air leakage value displayed by the display unit in real time according to the before-valve air leakage, and obtaining and displaying a corresponding vacuum descent speed value by searching the relation between the before-valve air leakage and the vacuum descent speed.
And the alarm unit 8 is used for giving an alarm when the current vacuum descending speed value reaches a preset alarm value.
It can be understood that the alarm value of the vacuum deceleration value may be a qualified value of a vacuum tightness test of the condensing steam turbine unit, or may be an alarm value in advance when the alarm value is slightly lower than the qualified value of the corresponding condensing steam turbine unit.
Correspondingly, as shown in fig. 2, the invention also discloses a vacuum tightness detection method of the condensing steam turbine unit, which comprises the following steps:
s1: after the outlet valve is opened and the vacuum-pumping equipment is started, the gas flow value of the gas-water separator exhaust gas is measured and displayed, and is recorded as a raw measurement value.
S2: and correcting the original measured value according to the environmental parameters of the gas-water separator, and recording as an exhaust gas volume correction value.
The method specifically comprises the following steps: firstly, measuring the gas temperature, humidity and pressure when the gas-water separator exhausts, correcting an original measured value according to the measured gas temperature value, humidity value and pressure value, calculating to obtain the original measured value after removing water vapor, and recording as a first corrected value of gas flow.
Then, measuring the water level value and the water temperature value of the gas-water separator; and calculating the variation of the gas flow value caused by the water level variation according to the water level value of the gas-water separator, and correcting the first correction value of the gas flow according to the variation of the water level value, wherein the first correction value is recorded as a second correction value of the gas flow.
And finally, calculating the variation of the gas flow value caused by the water temperature variation according to the water temperature value of the gas-water separator, and accordingly correcting a second corrected gas flow value, which is recorded as an exhaust gas amount corrected value.
During actual operation, a gas-water separator exhaust gas flow measuring device, a temperature measuring device, a humidity measuring device and a pressure measuring device can be arranged on the vacuumizing equipment, and the flow, the temperature, the humidity and the pressure of the gas-water separator exhaust gas are measured in real time; installing a water level measuring device and a water temperature measuring device of the gas-water separator; and an ambient temperature measuring device and a humidity measuring device which are arranged near the exhaust outlet valve of the condenser are installed. Calculating to obtain a gas flow value after removing water vapor according to the measured parameters of gas temperature, humidity, pressure, flow and the like when the gas-water separator exhausts; respectively calculating the variable quantity of the gas quantity discharged by the gas-water separator due to the water level change and the variable quantity of the air quantity dissolved in the water of the gas-water separator due to the water temperature and the water level change according to the measured water level value and the water temperature value of the gas-water separator, and correcting the gas quantity discharged by the gas-water separator according to the variable quantities; and the environment humidity measuring device and the temperature measuring device are respectively used for measuring the temperature and the humidity of the atmosphere in the environment in real time.
S3: and (4) after the outlet valve is closed and the vacuumizing equipment is started, measuring and displaying the gas flow value exhausted by the gas-water separator, and taking the gas flow value as the gas leakage value after the valve.
S4: and correcting the post-valve air leakage according to the atmospheric temperature and humidity parameters in the preset range of the outlet valve to obtain the post-valve air leakage after the moisture is removed, and recording as a post-valve air leakage correction value.
The basic purpose of the steps S3 and S4 is to determine the flow value of the leaked gas after the extraction outlet valve of the condenser, and the actual operation method is as follows:
closing an exhaust outlet valve of the condenser, starting a vacuumizing device, measuring and recording the exhaust gas flow value of the gas-water separator, and correcting parameters such as the exhaust temperature and the humidity of the gas-water separator, the water level and the water temperature of the gas-water separator and the like to obtain the exhaust gas flow value which does not contain water and eliminates the change influence of the water level, the water temperature and the like of the gas-water separator for recording; and measuring and recording parameters such as the ambient temperature, the humidity and the like near the exhaust outlet valve of the condenser at the moment, and converting the exhaust gas flow value without water content and without the influence of changes such as the water level, the water temperature and the like of the gas-water separator into the gas flow value containing water content leaked from the exhaust outlet valve of the condenser at the ambient temperature and the humidity.
It can be understood that the volume flow of the air leaking into the outlet valve is related to the differential pressure on the two sides of the leak point and the size of the leak point, but has little relation with the temperature and the humidity of the air, the atmospheric pressure and the pressure in the pipeline behind the air extraction valve do not change greatly, and the size of the leak point also does not change greatly in a short time, so the volume flow of the air leaking into the outlet valve does not change greatly under the normal condition, and the volume flow can be used as a constant in the subsequent production monitoring process after being determined by experiments. Although the volume flow rate does not vary much, the amount of pure air contained therein varies due to the large variation in the temperature and humidity of the air. When the flow rate of the exhaust gas from the moisture separator is determined to be the flow rate of the moisture-free air leaking into the moisture separator after the outlet valve is closed, the flow rate of the moisture-free air leaking into the moisture separator is converted into the flow rate of the moisture-free air leaking into the moisture separator based on the ambient temperature and the humidity at that time, and the calculated flow rate is recorded as a constant in the subsequent production process.
It should be noted that the above steps should be performed after the vacuuming equipment is repaired and obvious leakage points are eliminated; during the test, the record is carried out when the change of the flow value of the exhausted gas is stable.
S5: through tests, a corresponding relation curve between the air leakage amount before the valve and the vacuum descending speed value in the vacuum tightness test is established.
The method specifically comprises the following substeps:
s5.1: the method comprises the following steps of operating a condensing steam turbine set according to a working condition required by a vacuum tightness test, recording a gas flow value exhausted by a gas-water separator and subtracting a gas leakage value after a valve before the test to obtain a gas leakage value before the valve, then performing the vacuum tightness test, and recording a test result, namely a vacuum descending speed value after the test to obtain the gas leakage value before the valve and the vacuum descending speed value during the test; and recovering the condensing steam turbine set to the normal operation condition before the test.
It should be noted that the gas-water separator exhaust gas flow value, the gas leakage flow value behind the condenser exhaust outlet valve and the gas leakage flow value in front of the condenser exhaust outlet valve in the step S5.1 are all gas flow values with water and other influence factors removed; the method of rejection refers to step S2.
S5.2: leaking air with a preset flow into the condenser, and obtaining the before-valve air leakage value and the vacuum descending value in the test according to the method of the step S5.1 after the vacuum value and the measured value of the exhaust flow of the gas-water separator are stable; and recovering the condensing steam turbine set to the normal operation condition before the test.
It should be noted that the air amount leaked into the condenser manually needs to be small so as to avoid excessive vacuum drop, a special flow meter can be installed according to the operation experience, the valve of the flow meter is adjusted from small to large, and when the vacuum drops obviously (such as 1kPa drop) due to the leaked air, the opening of the adjusting valve of the flow meter is fixed until the test at this stage is finished.
S5.3: and (5) changing the air amount leaking into the condenser according to the method of the step S5.2, and carrying out a plurality of tests to obtain a plurality of pairs of data corresponding to the air leakage value before the valve and the vacuum descending speed value.
S5.4: if the test result of the vacuum tightness test is unqualified, the leakage point is searched and processed, and then the test is carried out again until the test is qualified, so that the air leakage value before the valve and the vacuum descending speed value after the vacuum tightness test is qualified are obtained.
S5.5: and (5) sorting and fitting the before-valve air leakage quantity value and the vacuum descending speed value obtained in the steps S5.1-S5.4 to obtain a corresponding relation curve between the before-valve air leakage quantity and the vacuum descending speed value in the vacuum tightness test.
S6: and measuring and calculating in real time to obtain an air displacement correction value and a post-valve air leakage correction value, and subtracting the post-valve air leakage correction value from the air displacement correction value to obtain a real-time variable pre-valve air leakage value.
S7: and obtaining the vacuum descending speed value which changes in real time by searching a corresponding relation curve between the air leakage amount before the valve and the vacuum descending speed value in the vacuum tightness test.
S8: and alarming when the vacuum descending speed value reaches a preset alarm value.
In the embodiments provided by the present invention, it should be understood that the disclosed system, system and method can be implemented in other ways. For example, the above-described system embodiments are merely illustrative, and for example, the division of the units is only one logical functional division, and other divisions may be realized in practice, for example, a plurality of units or components may be combined or integrated into another system, or some features may be omitted, or not executed. In addition, the shown or discussed mutual coupling or direct coupling or communication connection may be an indirect coupling or communication connection through some interfaces, systems or units, and may be in an electrical, mechanical or other form.
The units described as separate parts may or may not be physically separate, and parts displayed as units may or may not be physical units, may be located in one place, or may be distributed on a plurality of network units. Some or all of the units can be selected according to actual needs to achieve the purpose of the solution of the embodiment.
In addition, functional modules in the embodiments of the present invention may be integrated into one processing unit, or each module may exist alone physically, or two or more modules are integrated into one unit.
Similarly, each processing unit in the embodiments of the present invention may be integrated into one functional module, or each processing unit may exist physically, or two or more processing units are integrated into one functional module.
The invention is further described with reference to the accompanying drawings and specific embodiments. It should be understood that these examples are for illustrative purposes only and are not intended to limit the scope of the present invention. Further, it should be understood that various changes or modifications of the present invention may be made by those skilled in the art after reading the teaching of the present invention, and these equivalents also fall within the scope of the present application.
Claims (10)
1. The utility model provides a condensing steam turbine's vacuum tightness detecting system, is connected with evacuation equipment through exhaust duct including setting up the condenser in condensing steam turbine, the condenser, is equipped with the outlet valve on the exhaust duct, is equipped with deareator on the evacuation equipment, and its characterized in that, this detecting system still includes:
the exhaust gas quantity measuring unit is used for measuring and displaying the gas flow value exhausted by the gas-water separator; recording the measured value of the exhaust amount measuring unit after the outlet valve is opened and the vacuumizing device is started as an original measured value;
the air displacement correction unit is used for correcting the original measured value according to the environmental parameters of the gas-water separator and recording the corrected value as an air displacement correction value;
the post-valve air leakage storage and recording unit is used for storing and recording a post-valve air leakage value, and the post-valve air leakage value is a measured value of the post-valve air leakage measuring unit after the outlet valve is closed and the vacuumizing device is started;
the post-valve air leakage correction unit is used for correcting the post-valve air leakage according to the atmospheric temperature and humidity parameters in the preset range of the outlet valve to obtain the post-valve air leakage after the moisture is removed and recording the post-valve air leakage as a post-valve air leakage correction value;
the device comprises a pre-valve air leakage calculation and display unit, a post-valve air leakage correction unit and a post-valve air leakage correction unit, wherein the pre-valve air leakage calculation and display unit is used for calculating and displaying a pre-valve air leakage value which is a difference value of an air displacement correction value and a post-valve air leakage correction value;
the relation curve storage and recording unit is used for storing and recording a relation curve between the air leakage quantity before the valve and the vacuum descending speed;
the relationship between the air leakage quantity before the valve and the vacuum descending speed is as follows: the corresponding relation curve between the air leakage value before the valve and the vacuum descending speed value measured in the corresponding vacuum tightness experiment;
and the vacuum descent speed display unit is used for calculating the before-valve air leakage value displayed by the display unit in real time according to the before-valve air leakage, and obtaining and displaying the corresponding vacuum descent speed value by searching the relation between the before-valve air leakage and the vacuum descent speed.
2. The system for detecting vacuum tightness of a condensing steam turbine unit according to claim 1, wherein the displacement correction means includes:
the exhaust temperature measuring module is used for measuring the gas temperature when the gas-water separator exhausts;
the exhaust humidity measuring module is used for measuring the gas humidity of the gas-water separator during exhaust; the exhaust pressure measuring module is used for measuring the gas pressure of the gas-water separator during exhaust;
and the first exhaust gas volume correction module is used for correcting the original measured value according to the gas temperature, humidity and pressure measured by the exhaust temperature measurement module, the exhaust humidity measurement module and the exhaust pressure measurement module, calculating to obtain the original measured value after water vapor is removed, and recording the original measured value as a first gas flow volume correction value.
3. The system for detecting vacuum tightness of a condensing steam turbine unit according to claim 2, wherein the displacement correction unit further comprises:
the water level measuring module of the gas-water separator is used for measuring the water level value of the gas-water separator;
and the second exhaust gas quantity correcting module is used for calculating the variation of the gas flow quantity value caused by the water level variation according to the water level value of the gas-water separator, and correcting the first gas flow quantity correcting value according to the variation, and recording the first gas flow quantity correcting value as a second gas flow quantity correcting value.
4. The system for detecting vacuum tightness of a condensing steam turbine unit according to claim 3, wherein said displacement correction unit further comprises:
the water temperature measuring module of the gas-water separator is used for measuring the water temperature value of the gas-water separator;
and the exhaust third correction module is used for calculating the variation of the gas flow value caused by the water temperature variation according to the water temperature value of the gas-water separator, and correcting the gas flow second correction value according to the variation, and recording the second correction value as the exhaust correction value.
5. The system for detecting vacuum tightness of a condensing steam turbine unit according to claim 1, further comprising:
and the alarm unit is used for giving an alarm when the current vacuum descending speed value reaches a preset alarm value.
6. A method for detecting the vacuum tightness of a condensing steam turbine unit is characterized by comprising the following steps:
s1: after the outlet valve is opened and the vacuumizing equipment is started, measuring and displaying the gas flow value exhausted by the gas-water separator, and recording the gas flow value as an original measured value;
s2: correcting the original measured value according to the environmental parameters of the gas-water separator, and recording as an exhaust gas volume correction value;
s3: after the outlet valve is closed and the vacuumizing equipment is started, measuring and displaying the gas flow value exhausted by the gas-water separator, and taking the gas flow value as the gas leakage value after the valve;
s4: correcting the post-valve air leakage according to the atmospheric temperature and humidity parameters in the preset range of the outlet valve to obtain the post-valve air leakage after the moisture is removed, and recording the post-valve air leakage as a corrected value of the post-valve air leakage;
s5: through the test, establishing a corresponding relation curve between the air leakage amount before the valve and the vacuum descending speed value in the vacuum tightness test;
s6: measuring and calculating in real time to obtain an exhaust volume correction value and a post-valve air leakage correction value, and subtracting the post-valve air leakage correction value from the exhaust volume correction value to obtain a real-time variable pre-valve air leakage value;
s7: and obtaining the vacuum descending speed value which changes in real time by searching a corresponding relation curve between the air leakage amount before the valve and the vacuum descending speed value in the vacuum tightness test.
7. The method for detecting vacuum tightness of a condensing steam turbine unit according to claim 6, wherein said step S2 includes:
and measuring the gas temperature, humidity and pressure when the gas-water separator exhausts, correcting the original measured value according to the measured gas temperature value, humidity value and pressure value, calculating to obtain the original measured value after removing water vapor, and recording as a first corrected value of the gas flow.
8. The method for detecting vacuum tightness of a condensing steam turbine unit according to claim 7, wherein said step S2 further comprises:
measuring the water level value and the water temperature value of the gas-water separator;
calculating the variation of the gas flow value caused by the water level variation according to the water level value of the gas-water separator, and accordingly correcting the first correction value of the gas flow, and recording the first correction value as a second correction value of the gas flow;
and calculating the variation of the gas flow value caused by the water temperature variation according to the water temperature value of the gas-water separator, and correcting a second corrected gas flow value according to the variation of the water temperature value, wherein the second corrected gas flow value is recorded as an exhaust gas amount corrected value.
9. The method for detecting vacuum tightness of a condensing steam turbine unit according to claim 7, wherein the step S5 specifically includes the steps of:
s5.1: the method comprises the following steps of operating a condensing steam turbine set according to a working condition required by a vacuum tightness test, recording a gas flow value exhausted by a gas-water separator and subtracting a gas leakage value after a valve before the test to obtain a gas leakage value before the valve, then performing the vacuum tightness test, and recording a test result, namely a vacuum descending speed value after the test to obtain the gas leakage value before the valve and the vacuum descending speed value during the test; recovering the condensing steam turbine set to a normal operation condition before the test;
s5.2: leaking air with a preset flow into the condenser, and obtaining the before-valve air leakage value and the vacuum descending value in the test according to the method of the step S5.1 after the vacuum value and the measured value of the exhaust flow of the gas-water separator are stable; recovering the condensing steam turbine set to a normal operation condition before the test;
s5.3: changing the air quantity leaking into the condenser and carrying out a plurality of tests according to the method of the step S5.2 to obtain a plurality of pairs of data corresponding to the air leakage quantity value before the valve and the vacuum descending speed value;
s5.4: if the test result of the vacuum tightness test is unqualified, searching and processing a leakage point, and then testing again until the test is qualified to obtain a valve front air leakage value and a vacuum descending speed value after the vacuum tightness test is qualified;
s5.5: and (5) sorting and fitting the before-valve air leakage quantity value and the vacuum descending speed value obtained in the steps S5.1-S5.4 to obtain a corresponding relation curve between the before-valve air leakage quantity and the vacuum descending speed value in the vacuum tightness test.
10. The method for detecting vacuum tightness of a condensing steam turbine unit according to claim 6, wherein said step S7 is followed by the step of:
s8: and alarming when the vacuum descending speed value reaches a preset alarm value.
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