阅读说明：本技术 汽轮机系统高压加热器管侧泄漏检测方法及装置 (Method and device for detecting pipe side leakage of high-pressure heater of steam turbine system ) 是由 俞卫新 秦攀 崔传涛 季新叶 曾胜龙 刘岩 陈啸 于 2021-03-25 设计创作，主要内容包括：本发明涉及一种汽轮机系统高压加热器管侧泄漏检测方法及装置,其中方法包括：首先对同负荷工况下疏水调门的开度增加值、凝结水流量计、再热减温水流量计和给水流量计读数的偏差值、高压加热器的上端差、高压加热器水位、同负荷工况下高压加热器的温升降低作为判据,并在其中任意两项及以上同时发生时判定发生泄漏。与现有技术相比,本发明具有泄漏检测准确率高等优点。(The invention relates to a method and a device for detecting the side leakage of a high-pressure heater pipe of a steam turbine system, wherein the method comprises the following steps: firstly, the opening added value of the drainage regulating valve under the same load working condition, the deviation value of the readings of the condensed water flowmeter, the reheated desuperheating water flowmeter and the water supply flowmeter, the upper end difference of the high-pressure heater, the water level of the high-pressure heater and the temperature rise reduction of the high-pressure heater under the same load working condition are taken as criteria, and the leakage is judged to occur when any two or more of the two occur simultaneously. Compared with the prior art, the method has the advantages of high accuracy of leakage detection and the like.)

1. A method for detecting the pipe side leakage of a high-pressure heater of a steam turbine system is characterized by comprising the following steps:

acquiring the opening degree of a drainage damper under the same-load working condition, judging whether the opening degree is increased to exceed a pre-configured first threshold value, and if so, outputting a first early warning signal;

sampling values of a condensate flow meter (51), a reheat temperature-reducing water flow meter (52) and a feed water flow meter (53) are obtained, whether the deviation value exceeds a pre-configured second threshold value or not is judged, and if yes, a second early warning signal is output;

acquiring the upper end difference of the high-pressure heater, judging whether the upper end difference rises to reach a preset third set threshold value, and if so, outputting a third early warning signal;

acquiring the water level of the high-pressure heater, judging whether the water level rises to a high I value, and if so, outputting a fourth early warning signal;

acquiring the temperature rise of the high-pressure heater under the same load working condition, judging whether the temperature rise is reduced and exceeds a fifth set threshold value, and if so, outputting a fifth early warning signal;

and when at least two of the first early warning signal, the second early warning signal, the third early warning signal, the fourth early warning signal and the fifth early warning signal are received, judging that the high-pressure heater leaks, and outputting an alarm signal.

2. The method of claim 1, wherein the first threshold is 10%.

3. The method of claim 1, wherein the offset value is:

G₁-G₂-G₃

wherein: g₁For the sampled value of the condensate flowmeter (51), G₂Sampled value, G, for reheat desuperheater flowmeter (52)₃The second threshold value is 20t/h for the value sampled by the water meter (53).

4. The method of claim 1, wherein the third predetermined threshold is 2 degrees celsius.

5. The method of claim 1, wherein the fifth threshold is 5 degrees celsius.

6. A steam turbine system high-pressure heater pipe side leakage detection device comprises a boiler (11), a high-pressure heater group, a deaerator (4) and a water feeding pump (15), wherein the input end of the deaerator (4) is connected to a condensed water pipeline (35), the output end of the deaerator is connected to the input end of the water feeding pump (15), the output end of the water feeding pump (15) is connected to the boiler (11) through the high-pressure heater group, and the output end of the water feeding pump (15) is further connected to a reheater desuperheating water pipeline;

the device is characterized in that the bottom of each high-pressure heater in the high-pressure heater group is provided with a drainage throttle, a condensed water flowmeter (51) is arranged between the deaerator (4) and the water feed pump (15), a reheater desuperheating water flowmeter (52) is arranged on a reheater desuperheating water pipeline, a water feed flowmeter (53) is arranged between a first high-pressure heater and the boiler (11), a water level meter is arranged on the high-pressure heater, the device further comprises a controller, and the controller is configured to execute the following steps:

acquiring the opening degree of a drainage damper under the same-load working condition, judging whether the opening degree is increased to exceed a pre-configured first threshold value, and if so, outputting a first early warning signal;

acquiring sampling values of a condensate flow meter (51), a desuperheating water flow meter (52) and a feed water flow meter (53), judging whether the deviation value exceeds a second preset threshold value, and if so, outputting a second early warning signal;

acquiring the upper end difference of the high-pressure heater, judging whether the upper end difference rises to reach a preset third set threshold value, and if so, outputting a third early warning signal;

acquiring the water level of the high-pressure heater, judging whether the water level rises to a high I value, and if so, outputting a fourth early warning signal;

acquiring the temperature rise of the high-pressure heater under the same load working condition, judging whether the temperature rise is reduced and exceeds a fifth set threshold value, and if so, outputting a fifth early warning signal;

and when at least two of the first early warning signal, the second early warning signal, the third early warning signal, the fourth early warning signal and the fifth early warning signal are received, judging that the high-pressure heater leaks, and outputting an alarm signal.

7. The steam turbine system high pressure heater tube side leak detection apparatus of claim 6, wherein the first threshold value is 10%.

8. The steam turbine system high pressure heater tube side leakage detection apparatus of claim 6, wherein the offset value is:

G₁-G₂-G₃

wherein: g₁For the sampled value of the condensate flowmeter (51), G₂Sampled value, G, for reheat desuperheater flowmeter (52)₃The second threshold value is 20t/h for the value sampled by the water meter (53).

9. The steam turbine system high pressure heater tube side leak detection device of claim 6, wherein the third set threshold is 2 degrees celsius.

10. The steam turbine system high pressure heater tube side leakage detection apparatus of claim 6, wherein the fifth set threshold is 5 degrees celsius.

Technical Field

The invention relates to the field of leakage detection of a high-pressure heater of a steam turbine, in particular to a method and a device for detecting the leakage of a high-pressure heater pipe side of a steam turbine system.

Background

Under the new trend of the power industry, the low-load running time of the coal-fired generator set is increased, the start and stop are frequent, and the running safety of the generator set is adversely affected. Meanwhile, the requirement on the operation safety of the coal-fired power generating unit is continuously improved, and the improvement of the safety level of the unit by using a new technology is urgent.

The high-pressure heater is used as a heat conversion device and widely applied to a heat regeneration system of a large thermal power generating unit, and the working principle of the high-pressure heater is as follows: high-temperature and high-pressure superheated steam is pumped out from the steam turbine to heat the feed water in the high-pressure heater, so that the temperature difference between the feed water entering the boiler and the hearth is reduced, and the heat exchange efficiency is improved. The high-pressure heater is of a surface structure, the temperature difference and the pressure difference between steam and feed water are large, and in addition, factors such as overlarge thermal stress generated during starting, unstable water level of the heater, damage and destruction of a working medium to a tube bundle, damage of self vibration of the tube bundle and the like easily cause the reduction of the mechanical strength of the heat exchange tube and induce the leakage of the heater. After the high pressure feed water heater leaks, the influence to unit security has:

1. the leakage pipe forms high-pressure water supply impact on surrounding pipe bundles, so that the leakage pipe bundles are increased, and the leakage is more and more serious.

2. The water level of the high-pressure heater rises sharply, and the continuous rising of the water level has safety risks such as disconnection of the high-pressure heater and the like.

3. The shutdown of the high-pressure heater, the increase of drainage flow, the increase of the rotating speed of a water feeding pump turbine, the reduction of the load carrying capacity of a unit and the like are caused, and the safe operation is influenced.

Leakage of the high-pressure heater also has important influence on the unit operation economy, such as deterioration of heat exchange effect, increase of operation end difference and reduction of water supply temperature, which causes reduction of operation economy. Taking a certain 600MW unit as an example, the high-pressure heater is disconnected due to leakage of the high-pressure heater, the disconnection and maintenance of the high-pressure heater requires more than three days, and during the period, the coal consumption of the unit in operation is increased by 13.40g/kWh, thus the operation economy is seriously influenced.

It can be seen that the leakage of the high-pressure heater has important influence on the operation safety and economy of the unit, so that the timely and accurate discovery of the leakage of the high-pressure heater is very necessary: (1) operation measures can be taken in time, and leakage accidents are effectively prevented from being expanded; (2) the unit output reduction force caused by leakage is reduced, and even the risk of non-stop is reduced; (3) avoiding the great increase of the coal consumption of the unit due to serious leakage.

At present, the leakage of the high-pressure heater is mainly judged by people, the judgment is carried out according to the abnormity of related data such as the operation end difference of the heater, the change of water supply flow, the opening of a drain valve and the like and by means of abundant operation experience and historical trend of the data, the requirements on the capability and experience of operators are high, when the operators find that the related parameters of the high-pressure heater are abnormal, obvious leakage occurs, the adverse effect is generated on the safe operation of a unit, and an intelligent judgment system related to the leakage of the heater is lacked.

Disclosure of Invention

The invention aims to provide a method and a device for detecting the pipe side leakage of a high-pressure heater of a steam turbine system, which have the advantages that the leakage detection accuracy is improved, the pipe side leakage accident of the high-pressure heater of the steam turbine can be found in time, the leakage early warning is sent out, and a power generation enterprise can take measures in time, so that the leakage is prevented from being further expanded, and the safety accident is avoided.

The purpose of the invention can be realized by the following technical scheme:

a method for detecting the pipe side leakage of a high-pressure heater of a steam turbine system comprises the following steps:

acquiring the opening degree of a drainage damper under the same-load working condition, judging whether the opening degree is increased to exceed a pre-configured first threshold value, and if so, outputting a first early warning signal;

acquiring sampling values of the condensate flow meter, the reheating temperature-reducing water flow meter and the water supply flow meter, judging whether the deviation value exceeds a second preset threshold value, and if so, outputting a second early warning signal;

acquiring the upper end difference of the high-pressure heater, judging whether the upper end difference rises to reach a preset third set threshold value, and if so, outputting a third early warning signal;

acquiring the water level of the high-pressure heater, judging whether the water level rises to a high I value, and if so, outputting a fourth early warning signal;

acquiring the temperature rise of the high-pressure heater under the same load working condition, judging whether the temperature rise is reduced and exceeds a fifth set threshold value, and if so, outputting a fifth early warning signal;

and when at least two of the first early warning signal, the second early warning signal, the third early warning signal, the fourth early warning signal and the fifth early warning signal are received, judging that the high-pressure heater leaks, and outputting an alarm signal.

The first threshold is 10%.

The deviation value is as follows:

G₁-G₂-G₃

wherein: g₁For sampled values of condensate flowmeters, G₂For the value of the sampled water-reducing water flowmeter, G₃The second threshold value is 20t/h for the sampling value of the water supply flowmeter.

The third set threshold is 2 degrees celsius.

The fourth set threshold is a high I value of the water level of the high-pressure heater.

The fifth set threshold is 5 degrees celsius.

A steam turbine system high-pressure heater pipe side leakage detection device comprises a boiler, a high-pressure heater group, a deaerator and a water feeding pump, wherein the input end of the deaerator is connected to a condensation water pipeline, the output end of the deaerator is connected to the input end of the water feeding pump, the output end of the water feeding pump is connected to the boiler through the high-pressure heater group, and the output end of the water feeding pump is also connected to a reheater desuperheating water pipeline; the device comprises a high-pressure heater group, and is characterized in that the bottom of each high-pressure heater in the high-pressure heater group is provided with a drainage regulating valve, a condensed water flowmeter is arranged between a deaerator and a feed pump, a reheater desuperheating water flowmeter is arranged on a reheater desuperheating water pipeline, a feed water flowmeter is arranged between a first high-pressure heater and a boiler, a water level meter is arranged on the high-pressure heater, the device further comprises a controller, and the controller is configured to execute the steps.

Compared with the prior art, the invention has the following beneficial effects:

1) the leakage detection accuracy is improved, the leakage accident of the high-pressure heater pipe side of the steam turbine can be found in time, the leakage early warning is sent out, and a power generation enterprise can take measures in time to prevent the leakage from further expanding and avoid causing safety accidents.

2) The leakage early warning device is suitable for leakage early warning of a certain high-pressure heater and leakage early warning of multiple high-pressure heaters, is high in practicability, and can meet different requirements of power generation enterprises.

3) The leakage at the pipe side of the high-pressure heater can be found in time, the disconnection time of the high-pressure heater is reduced, and the economic loss caused by the leakage of the high-pressure heater is reduced.

Drawings

FIG. 1 is a schematic structural diagram of an application system according to an embodiment of the present invention;

FIG. 2 is a partial schematic view of a high pressure heater according to an embodiment of the present invention;

wherein: 1. the system comprises a first high-pressure heater, a second high-pressure heater, a third high-pressure heater, a deaerator, a boiler, a 12 high-pressure turbine cylinder, a 13 high-pressure turbine cylinder, a 14 medium-pressure turbine cylinder, a generator, a 15 water feed pump, a 21 primary steam extraction pipeline, a 22 secondary steam extraction pipeline, a 23 tertiary steam extraction pipeline, a 24 quaternary steam extraction pipeline, a 31 main steam pipeline, a 32 high-pressure cylinder steam extraction pipeline, a 33 reheat steam pipeline, a 34 medium-pressure turbine cylinder steam extraction pipeline, a 35 condensed water pipeline, a 36 reheater desuperheating water pipeline, a 37 water feed pipeline, a 41 first drain trap, a 42 second drain trap, a 43 third drain trap, a 51 water flow meter, a 52 reheater desuperheating water flow meter, a 53 water flow meter.

Detailed Description

The invention is described in detail below with reference to the figures and specific embodiments. The present embodiment is implemented on the premise of the technical solution of the present invention, and a detailed implementation manner and a specific operation process are given, but the scope of the present invention is not limited to the following embodiments.

Referring to fig. 1 and 2, the whole monitoring device is installed in a high pressure heater system, and includes a first high pressure heater 1, a second high pressure heater 2, a third high pressure heater 3, a deaerator 4, a boiler 11, a steam turbine high pressure cylinder 12, a steam turbine intermediate pressure cylinder 13, a generator 14, a water feed pump 15, a primary steam extraction pipeline 21, a secondary steam extraction pipeline 22, a tertiary steam extraction pipeline 23, a quaternary steam extraction pipeline 24, a main steam pipeline 31, a high pressure cylinder steam extraction pipeline 32, an intermediate pressure cylinder steam inlet pipeline 33, an intermediate pressure steam extraction pipeline 34, a condensate water pipeline 35, a reheater desuperheating water pipeline 36, a water feed pipeline 37, a first drain throttle 41, a second drain throttle 42, a third drain throttle 43, a condensate water flow meter 51, a reheater desuperheating water flow meter 52, and a water flow meter 53.

The boiler 11 is provided with a feed water inlet and a steam outlet, the steam outlet enters the high-pressure steam turbine cylinder 12 through the main steam pipeline 31, the steam does work through the high-pressure steam turbine cylinder 12 and then enters the boiler 11 through the high-pressure steam cylinder exhaust pipeline 32 for heating, the reheated steam enters the intermediate steam turbine cylinder 13 for doing work, the steam after doing work is exhausted through the intermediate steam cylinder exhaust pipeline 34, the steam is condensed into water and enters the deaerator 4 for heating after entering the condensed water pipeline 35, and the feed water sequentially passes through the third high-pressure heater 3, the second high-pressure heater 2 and the first high-pressure heater 1 for heating and then enters the boiler 11;

the water outlet end of the deaerator 4 is connected with the water inlet end of the water feeding pump 15, the water outlet end of the water feeding pump 15 is connected with the water inlet end of the third high-pressure heater 3, the water outlet end of the third high-pressure heater 3 is connected with the water inlet end of the second high-pressure heater 2, the water outlet end of the second high-pressure heater 2 is connected with the water inlet end of the first high-pressure heater 1, and the water outlet end of the first high-pressure heater 1 is connected with the inlet of a water feeding pipeline 37 of the boiler 11;

the bottoms of the first high-pressure heater 1, the second high-pressure heater 2 and the third high-pressure heater 3 are provided with drain outlets; a drain outlet at the bottom of the first high-pressure heater 1 is connected with a second high-pressure heater 2, a drain outlet at the bottom of the second high-pressure heater 2 is connected with a third high-pressure heater 3, and a drain outlet at the bottom of the third high-pressure heater 3 is connected with a deaerator 4;

the two ends of the first-stage steam extraction pipeline 21 are respectively connected with the steam turbine high-pressure cylinder 12 and the first high-pressure heater 1, the two ends of the second-stage steam extraction pipeline 22 are respectively connected with the steam turbine high-pressure cylinder 12 and the second high-pressure heater 2, the two ends of the third-stage steam extraction pipeline 23 are respectively connected with the steam turbine medium-pressure cylinder 13 and the third high-pressure heater 3, and the two ends of the fourth-stage steam extraction pipeline 24 are respectively connected with the steam turbine medium-pressure cylinder 13 and the deaerator 4;

the first drainage damper 41 is arranged on a drainage pipeline of the first high-pressure heater 1, the second drainage damper 42 is arranged on a drainage pipeline of the second high-pressure heater 2, and the third drainage damper 43 is arranged on a drainage pipeline of the third high-pressure heater 3; the condensate flow meter 51 is installed on the feed pump inlet line, the reheater desuperheating water flow meter 52 is installed on the reheater desuperheating water line, and the feed water flow meter 53 is installed on the first high pressure heater outlet line.

The influence of the high-pressure heater pipe side leakage on the operation parameters is researched, the quantitative relation between the high-pressure heater pipe side leakage and the parameters such as the normal drainage valve opening, the flow deviation, the high-pressure heater upper end difference, the high-pressure heater water level, the high-pressure heater temperature rise and the like is established, the judgment basis of the high-pressure heater pipe side leakage is determined, the high-pressure heater leakage accident is found in time, and the analysis process is as follows:

the method comprises the following steps: the method comprises the steps that leakage occurs on the pipe side of a high-pressure heater, feed water leaks to the steam side, and enters a next-stage heater through a drain pipeline of the high-pressure heater, so that the drain flow of the high-pressure heater is increased, specifically, the opening of a normal drain throttle of the high-pressure heater is increased under the same load working condition, and the opening of the normal drain throttle of the high-pressure heater under the same load working condition is increased by 10% to serve as one of judgment bases for the pipe side leakage of;

step two: the leakage of the pipe side of the high-pressure heater, the feed water leakage to the steam side, the feed water enters the next-stage heater through the drain pipeline of the high-pressure heater, the drain flow entering the deaerator 4 is increased, and the specific embodiment is that the reading G of the condensed water flowmeter 51 is shown as₁Reheater desuperheater flowmeter 52 reading G₂Reading G of water supply flowmeter 53₃Deviation increased, G₁-G₂-G₃Not less than 20t/h is used as one of judgment bases for the pipe side leakage of the high-pressure heater;

step three: the leakage of the high-pressure heater tube side and the leakage of the feed water to the steam side cause the heat exchange effect of the heater to be poor, the water temperature at the outlet of the high-pressure heater is reduced, the upper end difference is increased, and the upper end difference pswsat _ t (P) of the high-pressure heater is reduced₃+P₀)-t_3csThe temperature is more than or equal to 2 ℃ as one of judgment bases of the side leakage of the pipe;

step four: the pipe side of the high-pressure heater leaks, feed water leaks to the steam side, the water level of the high-pressure heater rises, and the high water level value I of the high-pressure heater is used as one of judgment bases for pipe side leakage;

step five: the pipe side of the high-pressure heater leaks, feed water leaks to the steam side, the heat exchange effect of the heater is poor, the temperature rise of the high-pressure heater is reduced, and the temperature rise of the high-pressure heater under the same load working condition is reduced by more than 5 ℃ to serve as one of judgment bases for pipe side leakage;

the five judgment bases for judging the leakage of the high-pressure heater pipe side have accidental factors to a certain extent, and in order to improve the judgment accuracy, two or more than two of the five judgment bases are simultaneously used as final judgment bases for the leakage of the high-pressure heater pipe side.

Finally, the method for detecting the pipe side leakage of the high-pressure heater of the steam turbine system is designed, and comprises the following steps:

acquiring the opening degree of a drainage damper under the same-load working condition, judging whether the opening degree is increased to exceed a pre-configured first threshold value, and if so, outputting a first early warning signal;

acquiring sampling values of the condensate flow meter, the desuperheating water flow meter and the water supply flow meter, judging whether the deviation value exceeds a second preset threshold value, and if so, outputting a second early warning signal;

acquiring the upper end difference of the high-pressure heater, judging whether the upper end difference rises to reach a preset third set threshold value, and if so, outputting a third early warning signal;

acquiring the water level of the high-pressure heater, judging whether the water level rises to a high I value, and if so, outputting a fourth early warning signal;

acquiring the temperature rise of the high-pressure heater under the same load working condition, judging whether the temperature rise is reduced and exceeds a fifth set threshold value, and if so, outputting a fifth early warning signal;

and when at least two of the first early warning signal, the second early warning signal, the third early warning signal, the fourth early warning signal and the fifth early warning signal are received, judging that the high-pressure heater leaks, and outputting an alarm signal.

The example application analysis was performed as follows:

the embodiment analysis is carried out by taking a certain power plant 600MW unit as an example, and the unit is provided with three high-pressure heaters and one deaerator. The equipment is installed and named in number according to the structural schematic diagram of the embodiment, namely a first high-pressure heater 1, a second high-pressure heater 2, a third high-pressure heater 3 and a deaerator 4.

Under the working condition that the rated power of the unit is 600MW, the opening degree of a third drainage damper is 60%, the flow of condensed water is equal to the sum of the temperature reduction water flow and the water supply flow of a reheater, the upper end difference of a third high-pressure heater is 0 ℃, the water level of the high-pressure heater is not abnormal, and the temperature rise of the third high-pressure heater is 44.5 ℃. The unit operates stably, and all operating parameters are normal.

Along with the increase of the start-stop times and the operation time of the unit, the water level of the third high-pressure heater rises under the rated power working condition of the unit, and the opening degree of the normal drainage damper is increased to 70%. The opening increment of the third drainage damper under the same load working condition is more than 10%, the condensate flow-reheating temperature-reducing water flow-feed water flow is more than or equal to 20t/h, and the two judgments trigger the third high-pressure heater pipe side leakage alarm. The opening degree of the third drainage damper is gradually increased in the running process of the unit, and the fact that the third high-pressure heater pipe side leaks is further clarified along with the phenomena of rising of the water level of the heater, lowering of the water outlet temperature of the heater and the like.

The unit operator takes the high-pressure heater separation measure, exits the steam side operation of the high-pressure heater, does not obviously reduce the water level, exits the water side operation of the high-pressure heater, switches to the water side bypass operation, and obviously reduces the water level of the heater. And opening a manhole door of the third high-pressure heater after cooling, pressurizing and checking leakage at the steam side of the third high-pressure heater, finding leakage of 7 pipe bundles, performing pipe plugging treatment on a leakage pipeline, pressurizing and rechecking leakage points, avoiding leakage, recovering normal operation of the high-pressure heater after reinstalling, and ensuring normal operation parameters of a regenerative system.

Through the scheme, the influence of the intelligent early warning system of the heater on the operation safety and the economical efficiency of the steam turbine can be seen in the following aspects.

1. The leakage of the third high-pressure heater is timely and accurately found and early warned, the leakage of 7 heater tube bundles is detected and found, and the accuracy of analysis and judgment is verified;

2. after early warning, the operators of the unit take measures in time, so that the leakage accident is effectively prevented from being enlarged, and the safety accident caused by leakage is avoided, even the unit is not in a wind risk;

3. if the leakage of the high-pressure heater cannot be found in time, the heat exchange effect is deteriorated, the operation end difference is increased, and the water supply temperature is reduced due to the leakage, so that the coal consumption of the unit is increased by more than 2g/kWh, and the operation economy of the unit is seriously influenced.