A reaction steam turbine based on extraction condensation

Abstract

The present invention relates to the technical field of reaction steam turbines, and in particular to a reaction steam turbine based on extraction condensation, including an inner cylinder and blades, including: a steam injection module; a steam condensation module; a steam extraction module; a control module, which is used to determine whether the working stability of the steam turbine meets the requirements according to the blade rotation speed, and adjust the injection speed of the high-temperature steam when it does not meet the requirements, or determine whether the reaction degree of the exhaust steam body to the blades meets the requirements according to the inner cylinder gas pressure, and when the reaction degree of the exhaust steam body to the blades does not meet the requirements, the instantaneous rate of steam extraction of the extraction valve is initially adjusted, and the mechanical performance stability of the extraction valve is determined to be unsatisfactory according to the change in the temperature of the extraction valve port, and the instantaneous rate of steam extraction of the extraction valve is adjusted for the second time. The present invention realizes the improvement of the working stability of the steam turbine and the reduction of the reaction degree of the exhaust steam body to the blades.

Description

Technical Field

[0001] The invention relates to the technical field of reaction steam turbines, and in particular to a reaction steam turbine based on extraction and condensation of steam. Background Art

[0002] In the prior art, the steam of the reaction steam turbine that extracts and condenses steam expands not only in the nozzle, but also in the moving blades, so that the moving blades are simultaneously subjected to the impact force of the steam flow and the reaction force of the accelerated steam expansion. The cross-sectional shapes of the moving blades and the stationary blades are basically the same. The steam continues to expand in the moving blade grid, increasing the flow rate and generating a reaction force on the moving blade grid, thereby driving the rotor to rotate and do work. The design includes the working principle of the reaction steam turbine, and has the function of extracting steam from the middle stage of the steam turbine to supply heat users, and discharging the remaining steam into the condenser for condensation. This type of steam turbine is widely used in many fields such as electricity, chemical industry, and shipbuilding.

[0003] Chinese Patent Publication No.: CN116085054A discloses a 28MW reaction back-pressure steam turbine, which includes a rotor, a front bearing box, a cylinder front, a rotary baffle, a cylinder rear, a rear bearing box, an I-beam, a center beam and a high-pressure main steam regulating combined valve; one end of the front bearing box is connected to one end of the cylinder front through an I-beam, and the other end of the cylinder front is connected to one end of the cylinder rear, one end of the rotor passes through the cylinder rear and cylinder front in sequence, and is inserted into the interior of one end of the front bearing box, a rotary baffle is provided on the rotor, and the rotary baffle is arranged in the inner cavity of the cylinder rear, the other end of the rotor is inserted into the interior of one end of the rear bearing box, and one end of the rear bearing box is connected to the other end of the cylinder rear through the center beam, a high-pressure main steam regulating combined valve is respectively provided on the outside of both sides of the cylinder front, and the high-pressure main steam regulating combined valve is connected to the steam inlet of the cylinder front through a pipeline. It can be seen that the 28MW reaction back-pressure steam turbine has the problems of low effective work efficiency of the jet gas on the blades due to the excessive impact force of the high-temperature steam on the inner wall of the nozzle, and high reaction force on the blades caused by the accumulated steam in the inner cylinder due to the low extraction rate of the extraction valve. Summary of the invention

[0004] To this end, the present invention provides a reaction steam turbine based on extraction condensation to overcome the problems in the prior art of low effective work efficiency of the injected steam on the blades due to excessive impact force of the high-temperature steam on the inner wall of the nozzle, and high reaction force on the blades caused by the accumulated steam in the inner cylinder due to the low extraction rate of the extraction valve.

[0005] To achieve the above object, the present invention provides a reaction steam turbine based on extraction condensation, comprising an inner cylinder and blades, including:

[0006] A steam injection module, used for accelerating the injection of high-temperature steam generated by heating the boiler onto the blades, comprising a nozzle connected to the blades;

[0007] A condensing module connected to the inner cylinder for cooling the condensed steam in the exhaust steam of the condensing steam turbine and discharging the condensed water from the steam turbine;

[0008] A steam extraction module connected to the inner cylinder for extracting non-condensable steam from the exhaust steam of the steam turbine, including a steam extraction valve;

[0009] A detection module, which is connected to the blade, the steam extraction module and the inner cylinder respectively, and is used to detect the blade rotation speed, the temperature of the steam extraction valve port and the inner cylinder air pressure respectively;

[0010] a control module, which is respectively connected to the steam injection module, the condensation module, the steam extraction module and the detection module, and is used to determine whether the working stability of the steam turbine meets the requirements according to the blade speed variance, and to adjust the injection speed of the high-temperature steam when it does not meet the requirements, or to determine whether the reaction degree of the exhaust steam on the blade meets the requirements according to the inner cylinder gas pressure,

[0011] Furthermore, when the reaction degree of the exhaust steam on the blades does not meet the requirements, the instantaneous extraction rate of the steam extraction valve is initially adjusted, and based on the change in the temperature of the steam extraction valve port, it is determined that the stability of the mechanical performance of the steam extraction valve does not meet the requirements, and the instantaneous extraction rate of the steam extraction valve is secondarily adjusted.

[0012] Furthermore, the condensing module comprises:

[0013] A condenser connected to the inner cylinder and used for condensing the condensed gas into the condensed water;

[0014] a circulating water pump connected to the condenser and used to transport condensed water in the circulating water pump to the condenser;

[0015] A condensate pump is connected to the condenser and is used for conveying the condensate out of the steam turbine.

[0016] Furthermore, the detection module includes:

[0017] A gyroscope connected to the blade to calculate the rotation speed of the blade by detecting the angular velocity of the blade;

[0018] a temperature sensor connected to the steam extraction valve port and used to detect the temperature of the steam extraction valve port;

[0019] The air pressure sensor is arranged on the inner wall of the inner cylinder close to the blades to detect the air pressure of the inner cylinder.

[0020] Furthermore, the control module is respectively connected to the nozzle and the gyroscope to obtain the blade speed and calculate the blade speed variance. If the blade speed variance is greater than a preset second variance, it is determined that the working stability of the turbine does not meet the requirements, and the injection speed of the high-temperature steam is increased.

[0021] Further, the increase range of the injection speed of the high-temperature gas is determined according to the difference between the preset second variance and the blade rotation speed variance.

[0022] Furthermore, the control module is connected to the air pressure sensor to preliminarily determine that the degree of reaction of the exhaust steam to the blades does not meet the requirements when the blade speed variance is greater than a preset first variance and less than or equal to the preset second variance, and obtain the inner cylinder air pressure. If the inner cylinder air pressure is greater than the preset air pressure, a second determination is made that the degree of reaction of the exhaust steam to the blades does not meet the requirements, and the instantaneous extraction rate of the extraction valve is initially adjusted.

[0023] Furthermore, the instantaneous steam extraction rate of the initially adjusted steam extraction valve is positively correlated with the preset air pressure.

[0024] Furthermore, the control module is connected to the temperature sensor to obtain the temperature of the steam extraction valve port detected in adjacent unit cycles and calculate the temperature change of the steam extraction valve port. If the temperature change of the steam extraction valve port is greater than or equal to a preset change, it is determined that the stability of the mechanical performance of the steam extraction valve does not meet the requirements, and the instantaneous steam extraction rate of the steam extraction valve is adjusted secondary.

[0025] Furthermore, the instantaneous steam extraction rate of the secondary regulated steam extraction valve is negatively correlated with the temperature change at the valve port of the steam extraction valve.

[0026] Furthermore, the calculation formula of the temperature change of the steam extraction valve port is:

[0027] T=|t i -t i+1 |

[0028] Wherein, T is the temperature change of the steam extraction valve port, t i is the valve port temperature of the steam extraction valve detected by the temperature sensor in the i-th cycle, t i+1 is the valve port temperature of the steam extraction valve detected by the temperature sensor in the (i+1)th cycle.

[0029] Compared with the prior art, the beneficial effect of the present invention lies in that the steam turbine of the present invention is provided with a steam injection module to accelerate the injection of high-temperature steam onto the blades. Since the inner wall of the nozzle is in a contracted shape, the high-temperature steam has a high impact force on the inner wall. Long-term high-temperature action may also cause phase change or thermal fatigue of the nozzle material, affecting the nozzle geometry and dimensional accuracy, resulting in reduced stability during the high-temperature steam injection process, thereby affecting the overall efficiency of the steam turbine. By adjusting the injection speed of the high-temperature steam, the steam flow state can be optimized so that the macroscopic kinetic energy of the steam is more effectively converted into microscopic kinetic energy, thereby improving the working capacity of the steam in the steam turbine, and further realizing the improvement of the working stability of the steam turbine. The steam turbine is provided with a steam extraction valve to extract non-condensable steam in the exhaust steam of the steam turbine. In the case that the steam extraction valve does not extract steam in time, This causes steam to accumulate near the blades, causing changes in the air pressure in the inner cylinder, which in turn leads to additional reaction force on the exhaust end of the blades. The reaction force will affect the uneven load on the blades, resulting in increased working stress and vibration frequency of the blades, which in turn affects the service life and performance of the blades. By adjusting the instantaneous extraction rate of the extraction valve, the reaction impact on the blades caused by exhaust steam backflow can be reduced, thereby further improving the working stability of the blades; by adjusting the instantaneous extraction rate of the extraction valve for the second time, the influence of changes in the stability of the mechanical properties of the extraction valve caused by the large internal and external temperature difference caused by multiple opening and closing of the extraction valve on the turbine can be reduced, thereby further improving the working stability of the steam turbine, reducing the degree of reaction of the exhaust steam on the blades and increasing the stability of the mechanical properties of the extraction valve.

[0030] Furthermore, the steam turbine described in the present invention adjusts the injection speed of the high-temperature steam by setting a preset second variance. Since the high-temperature steam carries a large amount of heat and energy during the injection process, when the steam impacts the inner wall of the nozzle, it may cause excessive stress in the nozzle and change the surface accuracy of the nozzle, thereby causing uneven flow rate of the steam ejected from the nozzle and a decrease in the blade speed. By increasing the injection speed of the high-temperature steam, the speed change caused by uneven force on the blades can be reduced, and the throttling loss of steam when flowing through the nozzle can be reduced, so that more steam energy can be used to do work, thereby improving the working efficiency of the steam turbine and further improving the working stability of the steam turbine.

[0031] Furthermore, the steam turbine described in the present invention performs an initial adjustment on the instantaneous extraction rate of the steam extraction valve by setting a preset air pressure. As the steam is pressed in the inner cylinder, the air pressure in the cylinder increases, and the high-temperature steam accumulated in the upper cavity of the inner cylinder generates a reaction force on the blades, resulting in uneven force on the blades, which in turn causes the blades to vibrate and affects their mechanical properties. By increasing the instantaneous extraction rate of the steam extraction valve, the steam in the cylinder is discharged in time, reducing the influence of air pressure on the blades, thereby improving the working stability and working efficiency of the steam turbine.

[0032] Furthermore, the steam turbine described in the present invention performs secondary regulation on the instantaneous extraction rate of the steam extraction valve by setting a preset change amount. Since the working strength of the spring inside the steam extraction valve is increased and the frequency of steam exchange around the valve port of the steam extraction valve is increased after the instantaneous extraction rate of the steam extraction valve is increased, the internal temperature fluctuation becomes larger and the impact and wear of the valve and seals are increased. By reducing the instantaneous extraction rate of the steam extraction valve, the deformation rate of the spring inside the steam extraction valve is reduced, the thermal stress change of the inner cylinder caused by excessive temperature change is reduced, and the service life of the valve and seal is increased, the mechanical performance stability of the steam extraction valve is improved, thereby improving the mechanical performance and stability of the steam turbine. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 It is a schematic diagram of the overall structure of a reaction steam turbine based on extraction condensation according to an embodiment of the present invention;

[0034] Figure 2 The overall structural block diagram of a reaction steam turbine based on extraction condensation according to an embodiment of the present invention;

[0035] Figure 3 It is a specific structural block diagram of a detection module of a reaction steam turbine based on extraction condensation according to an embodiment of the present invention;

[0036] Figure 4 The invention is a specific structural block diagram of a condensing module of a reaction steam turbine based on extraction condensation according to an embodiment of the present invention.

[0037] Explanation of the reference numerals: 1-inner cylinder, 2-gyroscope, 3-blade, 4-nozzle, 5-air pressure sensor, 6-steam extraction valve, 7-temperature sensor, 8-circulating water pump, 9-condenser, 10-condensate pump. DETAILED DESCRIPTION

[0038] In order to make the objects and advantages of the present invention more clearly understood, the present invention is further described below in conjunction with embodiments; it should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0039] The preferred embodiments of the present invention are described below with reference to the accompanying drawings. It should be understood by those skilled in the art that these embodiments are only used to explain the technical principles of the present invention and are not intended to limit the protection scope of the present invention.

[0040] It should be noted that, in the description of the present invention, terms such as "up", "down", "left", "right", "inside" and "outside" indicating directions or positional relationships are based on the directions or positional relationships shown in the drawings. This is merely for the convenience of description and does not indicate or imply that the device or element must have a specific orientation, be constructed and operated in a specific orientation. Therefore, it cannot be understood as a limitation on the present invention.

[0041] In addition, it should be noted that in the description of the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For those skilled in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0042] See also Figure 1 , Figure 2 , Figure 3 as well as Figure 4 As shown, they are respectively an overall structural schematic diagram of a reaction steam turbine based on extraction condensation according to an embodiment of the present invention, an overall structural block diagram, a specific structural block diagram of a detection module, and a specific structural block diagram of a condensation module. A reaction steam turbine based on extraction condensation according to the present invention comprises an inner cylinder 1 and blades 3, including:

[0043] A steam injection module, used for accelerating the injection of high-temperature steam generated by heating the boiler onto the blade 3, comprising a nozzle 4 connected to the blade 3;

[0044] A condensing module connected to the inner cylinder 1 for cooling the condensed steam in the exhaust steam of the condensing steam turbine and discharging the condensed water from the steam turbine;

[0045] A steam extraction module, which is connected to the inner cylinder 1 and is used to extract non-condensable steam from the exhaust steam of the steam turbine, and includes a steam extraction valve 6;

[0046] A detection module, which is respectively connected to the blade 3, the steam extraction module and the inner cylinder 1, and is used to detect the rotation speed of the blade 3, the valve port temperature of the steam extraction valve 6 and the air pressure of the inner cylinder 1 respectively;

[0047] a control module, which is respectively connected to the steam injection module, the condensation module, the steam extraction module and the detection module, and is used to determine whether the working stability of the steam turbine meets the requirements according to the speed variance of the blade 3, and to adjust the injection speed of the high-temperature steam when it does not meet the requirements, or to determine whether the reaction degree of the exhaust steam on the blade 3 meets the requirements according to the air pressure of the inner cylinder 1,

[0048] Furthermore, when the reaction degree of the exhaust steam on the blade 3 does not meet the requirements, the instantaneous extraction rate of the steam extraction valve is initially adjusted, and based on the temperature change at the valve port of the steam extraction valve 6, it is determined that the stability of the mechanical performance of the steam extraction valve 6 does not meet the requirements, and the instantaneous extraction rate of the steam extraction valve 6 is secondarily adjusted.

[0049] Specifically, the steam injection module further includes a steam booster connected to the nozzle 4 for providing power to the injected steam.

[0050] In practice, the steam turbine of the present invention is provided with a steam injection module to accelerate the high-temperature steam to be injected onto the blades 3. Since the inner wall of the nozzle 4 is in a contracted shape, the high-temperature steam has a high impact force on the inner wall. Long-term high temperature may also cause the nozzle 4 material to undergo phase change or thermal fatigue, affecting the geometry and dimensional accuracy of the nozzle 4, resulting in reduced stability during the high-temperature steam injection process, thereby affecting the overall efficiency of the steam turbine. By adjusting the injection speed of the high-temperature steam, the steam flow state can be optimized so that the macroscopic kinetic energy of the steam can be more effectively converted into microscopic kinetic energy, thereby improving the working capacity of the steam in the steam turbine, and further achieving improved working stability of the steam turbine. The steam turbine is provided with a steam extraction valve 6 to extract non-condensable steam from the exhaust steam of the steam turbine. When the steam extraction valve 6 fails to extract steam in time, steam will accumulate near the blades 3. The gathering causes the air pressure in the inner cylinder 1 to change, thereby causing additional reaction force on the exhaust end of the blade 3. The reaction force will affect the uneven load on the blade 3, resulting in increased working stress of the blade 3 and increased vibration frequency of the blade 3, which in turn affects the service life and performance of the blade 3. By adjusting the instantaneous rate of steam extraction of the extraction valve, the reaction impact on the blade 3 caused by the exhaust steam backflow is reduced, and the working stability of the blade 3 is further improved; by secondary adjustment of the instantaneous rate of steam extraction of the extraction valve 6, the influence of the change in the stability of the mechanical properties of the extraction valve 6 caused by the excessive internal and external temperature difference caused by multiple opening and closing of the extraction valve 6 on the turbine can be reduced, and the working stability of the turbine is further improved, the reaction degree of the exhaust steam on the blade 3 is reduced, and the mechanical stability of the extraction valve 6 is increased.

[0051] Specifically, the condensing module comprises:

[0052] A condenser 9, which is connected to the inner cylinder 1 and is used to condense the condensed gas into the condensed water;

[0053] a circulating water pump 8 connected to the condenser 9 for conveying condensed water in the circulating water pump 8 to the condenser 9;

[0054] A condensate pump 10 is connected to the condenser 9 and is used to transport the condensate out of the steam turbine.

[0055] Specifically, the steam exhausted by the steam turbine is cooled and condensed into water in the condenser 9 by circulating water in the tube wall of the condenser 9 , and the circulating water in the tube wall of the condenser 9 is transported by the circulating water pump 8 .

[0056] Specifically, the detection module includes:

[0057] A gyroscope 2 is connected to the blade 3 and detects the angular velocity of the blade 3 to calculate the rotation speed of the blade 3;

[0058] a temperature sensor 7 connected to the valve port of the steam extraction valve 6 and used to detect the valve port temperature of the steam extraction valve 6;

[0059] The air pressure sensor 5 is arranged on the inner wall of the inner cylinder 1 near the blade 3 to detect the air pressure of the inner cylinder 1.

[0060] Specifically, the gyroscope 2 is installed on the turbine blade 3, and the rotation speed of the blade 3 is obtained by detecting the angular velocity of the blade 3 and according to the straight-line distance from the gyroscope 2 to the center of the rotating shaft.

[0061] Specifically, the control module is connected to the nozzle 4 and the gyroscope 2 respectively to obtain the rotational speed of the blade 3 and calculate the rotational speed variance of the blade 3. If the rotational speed variance of the blade 3 is greater than a preset second variance, it is determined that the working stability of the turbine does not meet the requirements, and the injection speed of the high-temperature steam is increased.

[0062] Specifically, the increase range of the injection speed of the high-temperature gas is determined according to the difference between the preset second variance and the variance of the rotation speed of the blade 3 .

[0063] Specifically, the speed variance of blade 3 is the variance of the speed of blade 3 within several detection cycles. The calculation method of the speed variance of blade 3 is a conventional technical means well known to technical personnel in this field, so the calculation process of the speed variance of blade 3 will not be repeated here.

[0064] In practice, the general range of the preset second variance is [20200rpm 2 , 22100rpm 2 ].

[0065] Preferably, the preferred embodiment of the preset second variance is 21000rpm 2 .

[0066] Specifically, the difference between the second variance and the speed variance is preset to be 100 rpm. 2 When the difference between the preset second variance and the speed variance exceeds 100, the injection speed of the high-temperature gas increases to 1.1 times of the original value. When the difference between the preset second variance and the speed variance exceeds 100, the injection speed of the high-temperature gas increases to 1.1 times of the original value. 2 , the injection speed of high-temperature gas increases by 20m / s. For example, the difference between the preset second variance and the rotation speed variance is 300, the current injection speed of high-temperature gas is 350m / s, and the injection speed of high-temperature gas increases to: 350m / s×1.1+20m / s×2=425m / s.

[0067] In implementation, the steam turbine of the present invention adjusts the injection speed of the high-temperature steam by setting a preset second variance. Since the high-temperature steam carries a large amount of heat and energy during the injection process, when the steam impacts the inner wall of the nozzle 4, it may cause excessive stress in the nozzle 4, and the surface accuracy of the nozzle 4 changes, which in turn causes the flow rate of the steam ejected from the nozzle 4 to be uneven, resulting in a decrease in the rotation speed of the blade 3. By increasing the injection speed of the high-temperature steam, the rotation speed change caused by the uneven force on the blade 3 can be reduced, and the throttling loss of the steam when flowing through the nozzle 4 can be reduced, so that more steam energy can be used to do work, thereby improving the working efficiency of the steam turbine and further improving the working stability of the steam turbine.

[0068] Specifically, the control module is connected to the air pressure sensor 5, and is used to preliminarily determine that the degree of reaction of the exhaust steam to the blade 3 does not meet the requirements when the speed variance of the blade 3 is greater than the preset first variance and less than or equal to the preset second variance, and obtain the air pressure of the inner cylinder 1. If the air pressure of the inner cylinder 1 is greater than the preset air pressure, it is secondarily determined that the degree of reaction of the exhaust steam to the blade 3 does not meet the requirements, and the instantaneous extraction rate of the extraction valve is initially adjusted.

[0069] Specifically, the instantaneous steam extraction rate of the initially adjusted steam extraction valve is positively correlated with the preset air pressure.

[0070] Specifically, the instantaneous extraction rate of the steam extraction valve 6 is adjusted by the valve stem of the steam extraction valve 6.

[0071] In practice, the general value range of the preset first variance is [8200rpm 2 , 8290rpm 2 ].

[0072] Preferably, the preferred embodiment of the preset first variance is 8267rpm 2 .

[0073] In practice, the general value range of the preset air pressure is [180 kPa, 200 kPa].

[0074] Preferably, the preferred embodiment of the preset air pressure is 190 kPa.

[0075] Specifically, when the difference between the air pressure of the inner cylinder 1 and the preset air pressure is within 10kPa, the instantaneous extraction rate of the steam extraction valve 6 increases by 4m / s; when the difference between the air pressure of the inner cylinder 1 and the preset air pressure exceeds 10kPa, the instantaneous extraction rate of the steam extraction valve 6 increases by 2m / s for every 10kPa exceeding it. For example, when the difference between the air pressure of the inner cylinder 1 and the preset air pressure is 20kPa, the instantaneous extraction rate of the steam extraction valve 6 is 10m / s, and the instantaneous extraction rate of the steam extraction valve 6 increases to: 10m / s+4m / s+2m / s×2=18m / s.

[0076] During implementation, the steam turbine described in the present invention performs an initial adjustment on the instantaneous extraction rate of the steam extraction valve by setting a preset air pressure. Since the steam is pressed in the inner cylinder 1, the air pressure in the cylinder increases, and the high-temperature steam accumulated in the upper cavity of the inner cylinder 1 generates a reaction force on the blades 3, resulting in uneven force on the blades 3, which in turn causes the blades 3 to vibrate and affects the mechanical properties of the blades 3. By increasing the instantaneous extraction rate of the steam extraction valve, the steam in the cylinder is discharged in time, reducing the influence of the air pressure on the blades 3, thereby achieving improved working stability and working efficiency of the steam turbine.

[0077] Specifically, the control module is connected to the temperature sensor 7 to obtain the valve port temperature of the steam extraction valve 6 detected in adjacent unit cycles, and calculate the temperature change of the valve port of the steam extraction valve 6. If the temperature change of the valve port of the steam extraction valve 6 is greater than or equal to the preset change, it is determined that the mechanical performance stability of the steam extraction valve 6 does not meet the requirements, and the instantaneous steam extraction rate of the steam extraction valve 6 is adjusted for the second time.

[0078] Specifically, the instantaneous steam extraction rate of the secondary regulated steam extraction valve 6 is negatively correlated with the change in the valve port temperature of the steam extraction valve 6 .

[0079] Specifically, the calculation formula for the temperature change at the valve port of the steam extraction valve 6 is:

[0080] T=|t i -t i+1 |

[0081] Wherein, T is the temperature change of the valve port of the extraction valve 6, t i is the valve port temperature of the steam extraction valve 6 detected by the temperature sensor 7 in the i-th cycle, t i+1 It is the valve port temperature of the steam extraction valve 6 detected by the temperature sensor 7 in the (i+1)th cycle.

[0082] In practice, the preset change amount generally ranges from [10°C, 15°C].

[0083] Preferably, the preset change amount is 12°C.

[0084] Specifically, when the difference between the temperature change at the valve port of the extraction valve 6 and the preset temperature change is within 2°C, the instantaneous extraction rate of the extraction valve 6 is reduced to 0.95 times of the original value; when the difference between the temperature change at the valve port of the extraction valve 6 and the preset temperature change exceeds 2°C, the instantaneous extraction rate of the extraction valve 6 is reduced by 1m / s for every 1°C increase. For example, when the difference between the temperature change at the valve port of the extraction valve 6 and the preset temperature change is 4°C, the current instantaneous extraction rate of the extraction valve 6 is 16m / s, and the instantaneous extraction rate of the extraction valve 6 is reduced to 16m / s×0.95-1m / s×2=13.2m / s.

[0085] In practice, the steam turbine described in the present invention performs secondary regulation on the instantaneous extraction rate of the extraction valve 6 by setting a preset change amount. After the instantaneous extraction rate of the extraction valve 6 is increased, the working strength of the spring inside the extraction valve is increased, and the frequency of steam exchange around the valve port of the extraction valve is increased, resulting in larger internal temperature fluctuations, and increased impact and wear of valves and seals. By reducing the instantaneous extraction rate of the extraction valve 6, the deformation rate of the spring inside the extraction valve is reduced, and the thermal stress change of the inner cylinder 1 caused by excessive temperature change is reduced, the service life of the valve and seal is increased, and the mechanical performance stability of the extraction valve 6 is improved, thereby improving the mechanical performance and stability of the steam turbine.

[0086] So far, the technical solutions of the present invention have been described in conjunction with the preferred embodiments shown in the accompanying drawings. However, it is easy for those skilled in the art to understand that the protection scope of the present invention is obviously not limited to these specific embodiments. Without departing from the principle of the present invention, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after these changes or substitutions will fall within the protection scope of the present invention.

Claims

1. A reaction steam turbine based on extraction condensation, comprising an inner cylinder and blades, characterized in that: include: A steam injection module, used for accelerating the injection of high-temperature steam generated by heating the boiler onto the blades, comprising a nozzle connected to the blades; A condensing module connected to the inner cylinder for cooling the condensed steam in the exhaust steam of the condensing steam turbine and discharging the condensed water from the steam turbine; A steam extraction module connected to the inner cylinder for extracting non-condensable steam from the exhaust steam of the steam turbine, including a steam extraction valve; A detection module, which is connected to the blade, the steam extraction module and the inner cylinder respectively, and is used to detect the blade rotation speed, the temperature of the steam extraction valve port and the inner cylinder air pressure respectively; a control module, which is respectively connected to the steam injection module, the condensation module, the steam extraction module and the detection module, and is used to determine whether the working stability of the steam turbine meets the requirements according to the blade speed variance, adjust the injection speed of the high-temperature steam when it does not meet the requirements, and determine whether the reaction degree of the exhaust steam on the blade meets the requirements according to the inner cylinder gas pressure, and, when the reaction degree of the exhaust steam to the blades does not meet the requirements, the instantaneous extraction rate of the steam extraction valve is adjusted for the first time, and the mechanical performance stability of the steam extraction valve is determined to not meet the requirements according to the change in the temperature of the steam extraction valve port, and the instantaneous extraction rate of the steam extraction valve is adjusted for the second time; Wherein, the control module is connected to the nozzle and the gyroscope respectively to obtain the blade speed and calculate the blade speed variance. If the blade speed variance is greater than a preset second variance, it is determined that the working stability of the steam turbine does not meet the requirements, and the injection speed of the high-temperature steam is increased; The increase range of the injection speed of the high-temperature gas is determined according to the difference between the preset second variance and the blade rotation speed variance.

2. The reaction steam turbine based on extraction condensation according to claim 1, characterized in that: The condensing module comprises: A condenser connected to the inner cylinder and used for condensing the condensed gas into the condensed water; a circulating water pump connected to the condenser and used to transport condensed water in the circulating water pump to the condenser; A condensate pump is connected to the condenser and is used for conveying the condensate out of the steam turbine.

3. The reaction steam turbine based on extraction condensation according to claim 1, characterized in that: The detection module comprises: A gyroscope connected to the blade to calculate the rotation speed of the blade by detecting the angular velocity of the blade; a temperature sensor connected to the steam extraction valve port and used to detect the temperature of the steam extraction valve port; The air pressure sensor is arranged on the inner wall of the inner cylinder close to the blades to detect the air pressure of the inner cylinder.

4. The reaction steam turbine based on extraction condensation according to claim 3, characterized in that: The control module is connected to the air pressure sensor to preliminarily determine that the degree of reaction of the exhaust steam to the blades does not meet the requirements when the blade speed variance is greater than the preset first variance and less than or equal to the preset second variance, and obtain the inner cylinder air pressure. If the inner cylinder air pressure is greater than the preset air pressure, a second determination is made that the degree of reaction of the exhaust steam to the blades does not meet the requirements, and the instantaneous extraction rate of the extraction valve is initially adjusted.

5. The reaction steam turbine based on extraction condensation according to claim 4, characterized in that: The instantaneous steam extraction rate of the initially adjusted steam extraction valve is positively correlated with the preset air pressure.

6. The reaction steam turbine based on extraction condensation according to claim 3, characterized in that: The control module is connected to the temperature sensor to obtain the temperature of the steam extraction valve port detected in adjacent unit cycles and calculate the temperature change of the steam extraction valve port. If the temperature change of the steam extraction valve port is greater than or equal to a preset change, it is determined that the mechanical performance stability of the steam extraction valve does not meet the requirements, and the steam extraction instantaneous rate of the steam extraction valve is adjusted secondary.

7. The reaction steam turbine based on extraction condensation according to claim 6, characterized in that: The instantaneous steam extraction rate of the secondary regulated steam extraction valve is negatively correlated with the temperature change of the steam extraction valve port.

8. The reaction steam turbine based on extraction condensation according to claim 7, characterized in that: The calculation formula of the temperature change of the extraction valve port is: ， Wherein, T is the temperature change of the steam extraction valve port, is the valve port temperature of the steam extraction valve detected by the temperature sensor in the i-th cycle, is the valve port temperature of the steam extraction valve detected by the temperature sensor in the (i+1)th cycle.

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