CN219061775U - Shaft seal system of high-low steam turbine unit - Google Patents
Shaft seal system of high-low steam turbine unit Download PDFInfo
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- CN219061775U CN219061775U CN202223539367.XU CN202223539367U CN219061775U CN 219061775 U CN219061775 U CN 219061775U CN 202223539367 U CN202223539367 U CN 202223539367U CN 219061775 U CN219061775 U CN 219061775U
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Abstract
The utility model discloses a shaft seal system of a high-low steam turbine unit, which comprises a high-low unit and a low-low unit which are arranged in a high-low structure; and the shaft seal steam pipeline of the high-level unit is mutually independent from the shaft seal steam pipeline of the low-level unit. The utility model aims at the particularity of the high-low turbine unit, so that the shaft seal leakage of the high-low turbine unit is irrelevant to the shaft seal steam supply of the low turbine unit, and the shaft seal of the low turbine unit is also provided with a self-sealing steam shaft seal system for independently supplying steam, and the steam shaft seal system between the high-low turbine unit is not influenced by the elevation between the high-low turbine unit and the low turbine unit, thereby effectively simplifying the shaft seal steam supply pipeline arrangement between the high-low turbine unit, reducing the technical difficulty of the shaft seal steam supply pipeline arrangement, and reliably controlling the shaft seal steam supply parameters so as to ensure the safe and reliable operation of the shaft seal system of the high-low turbine unit.
Description
Technical Field
The utility model relates to a turbine unit, in particular to a shaft seal system for the turbine unit which is arranged in a high-low structure.
Background
The conventional turbine unit is of a single-shaft configuration structure, namely all cylinders (high-pressure cylinder, medium-pressure cylinder, low-pressure cylinder and the like) of the turbine unit are arranged on the same shaft system. In order to adapt to energy conservation and efficiency improvement, a brand new turbine unit structure, namely a high-position double-shafting configuration structure and a low-position double-shafting configuration structure, is currently available.
Fig. 1 schematically illustrates a typical high-low turbine unit (in the drawing, HP is a high-pressure cylinder, IP1 is a medium-pressure cylinder one, IP2 is a medium-pressure cylinder two, LP1 is a low-pressure cylinder one, LP2 is a low-pressure cylinder two, arrowed lines are steam system flows) having a high-level unit portion (typically a high-pressure cylinder, a medium-pressure cylinder, etc.) and a low-level unit portion (typically a medium-pressure cylinder, a low-pressure cylinder, etc.). The cylinders of the high-order unit are arranged on the same shaft system (namely, the high-order shaft system). The cylinders of the low-order unit are arranged on the same shaft system (namely, the low-order shaft system). The high-level unit and the low-level unit are arranged in floors with different elevations, and the height between the floors is Cheng Yao m or more.
Compared with the conventional turbine unit, the high-low steam turbine unit has the advantages that the cylinders of the high-level shafting are arranged close to the boiler, the distance between the cylinders and the outlet of the boiler is short, that is, the length of a high-temperature high-pressure pipeline of the boiler connected with the cylinders of the high-pressure shafting is short, and the consumption is low. Therefore, the steam parameters and the running efficiency of the whole unit are improved, the manufacturing cost of the whole project can be greatly reduced, the economic benefit for coal-fired power generation is remarkable, and the environmental protection technical requirements of carbon peak and carbon neutralization are met.
The turbine unit is driven to rotate by high-temperature and high-pressure steam entering the corresponding cylinder body to realize the work. In order to ensure reliable rotation of the rotor component in the corresponding cylinder and to reduce leakage and gas leakage of the rotor component and the corresponding cylinder at the rotary support, a shaft seal is provided between the main shaft of the rotor component and the end of the corresponding cylinder. In the high-pressure shafting, the main function of the shaft seal is to reduce the leakage of high-temperature and high-pressure steam; in the low-pressure shafting, the main function of the shaft seal is to avoid the leakage of the atmosphere into the cylinder body and the damage of vacuum. It follows that the shaft seal is one of the key structures for safe and smooth operation of the steam turbine.
In the turbine configuration, the shaft seal is composed of a static seal portion (e.g., a shaft seal partition) and a dynamic seal portion, and the dynamic seal is realized by auxiliary steam.
The steam shaft seal system of the conventional turbine unit is characterized in that steam supply pipelines of auxiliary steam are respectively connected to shaft seals of high pressure, medium pressure and low pressure, and the shaft seals of the high pressure and the medium pressure are communicated with the shaft seals of the low pressure. In this way, auxiliary steam is respectively conveyed to shaft seals of high pressure, medium pressure and low pressure through corresponding steam supply pipelines in the starting, stopping and low load operation processes of the steam turbine unit; in the normal operation process, the leaked steam generated at the high-pressure and medium-pressure shaft seals is conveyed to the low-pressure shaft seals after being cooled. That is, in the structure of the conventional turbine unit, there is a steam supply line for carrying out steam leakage to the shaft seal of low pressure at the shaft seal of high pressure and medium pressure.
The elevation difference between the high-level turbine unit and the low-level turbine unit is more than 50 m. According to the steam supply pipeline arranged by the shaft seal system of the conventional turbine unit, the flow of the shaft seal steam supply pipeline is greatly increased, so that the technical difficulty of arranging the shaft seal steam supply pipeline is increased, the flow resistance of steam along the shaft seal steam supply pipeline is obviously increased, the steam temperature is obviously reduced, the reliable control of the shaft seal steam supply parameters is not facilitated, and the technical hidden trouble is brought to the safe operation of the shaft seal system of the turbine unit.
Based on the particularity of the high-low turbine unit and the particularity of the existing shaft seal system, the existing shaft seal system cannot be reliably applied to the operation conditions of the high-low turbine unit, and the high-low turbine unit is required to be specifically designed according to the specificity of the high-low turbine unit.
Disclosure of Invention
The technical purpose of the utility model is that: aiming at the particularity of the high-low steam turbine set and the technical defects of the existing shaft seal system, the shaft seal system which can be reliably applied to the high-low steam turbine set is provided.
The technical aim of the utility model is achieved by the following technical scheme that the shaft seal system of the high-low steam turbine unit comprises the high-low unit and the low-low unit which are arranged in a high-low structure;
and the shaft seal steam pipeline of the high-level unit is mutually independent from the shaft seal steam pipeline of the low-level unit.
The technical measures aim at the particularity of the high-low steam turbine unit, the shaft seal steam pipeline of the high-low steam turbine unit and the shaft seal steam pipeline of the low-low steam turbine unit are independently arranged, and the high-low steam turbine unit is only provided with a shaft seal steam leakage system and a shaft seal-free steam supply system which are not communicated with the shaft seal steam supply system of the low-low steam turbine unit. Therefore, the steam shaft seal system between the high-order unit and the low-order unit is not influenced by elevation between the high-order unit and the low-order unit.
Therefore, the technical measures are beneficial to simplifying the arrangement structure of the shaft seal steam supply pipelines between the high-level unit and the low-level unit and reducing the technical difficulty of the arrangement of the shaft seal steam supply pipelines. Meanwhile, the shaft seal steam supply of the low-level turbine unit is not influenced by elevation between the high-level turbine unit and the low-level turbine unit, independent steam supply is facilitated, the shaft seal steam supply parameters are reliably controlled, the shaft seal system design and the pipeline arrangement are simplified, the safety and the reliability of the operation of the shaft seal system of the high-level turbine unit and the low-level turbine unit are further improved, and the pertinence is strong.
As one of the preferable schemes, a section of shaft seal of the high-level unit is connected with a high-level section of shaft seal steam leakage pipeline, and the downstream end of the high-level section of shaft seal steam leakage pipeline is connected with the deaerator; the deaerator can be replaced by other heaters;
the two-section shaft seal of the high-level unit is connected with a high-level two-section shaft seal steam leakage pipeline, and the downstream end of the high-level two-section shaft seal steam leakage pipeline is connected with the first heat exchanger.
The technical measures are based on the fact that the high-level unit is only provided with the shaft seal steam leakage system, the shaft seal steam supply system is not arranged, the shaft seal steam leakage at different shaft seals of the high-level unit is reliably recycled according to the steam characteristics of the shaft seal steam leakage system, waste is avoided, loss is reduced, and the high-level unit is energy-saving and environment-friendly.
Meanwhile, according to the shaft seal system structure, gradient arrangement of the steam seal pressure is formed at the shaft end of the high-level unit, so that steam leakage to the atmosphere caused by overhigh pressure difference can be reliably prevented, and the shaft seal effect is excellent.
Further, the arrangement position of the first heat exchanger is close to the high-level unit. The technical measure can directly and greatly shorten the flow of the shaft seal steam leakage pipeline of the high-level unit, is beneficial to simplifying the arrangement structure of the shaft seal steam leakage pipeline of the high-level unit, is beneficial to reducing the flow resistance of steam along the shaft seal steam leakage pipeline, reduces the ineffective temperature drop of the steam, and further ensures the effective recovery and reuse of the heat of the shaft seal steam leakage.
Further, the first heat exchanger is a water-steam heat exchanger and is provided with a first water side heat exchange pipeline, wherein the upstream end of the first water side heat exchange pipeline is connected with a condensate pump, and the downstream end of the first water side heat exchange pipeline is connected with a final-stage low-pressure heater;
the top of the first heat exchanger is connected with a first exhaust pipeline, the first exhaust pipeline is connected with a first shaft seal fan, and the first exhaust pipeline is used for exhausting uncondensed gas in the first heat exchanger to the atmosphere;
and the bottom of the first heat exchanger is connected with a first drainage pipeline, and the first drainage pipeline is used for draining water in the first heat exchanger.
The technical measures aim at the particularity of air entrainment and steam leakage of steam at the two-stage shaft seal of the high-level unit, and the steam leakage is subjected to heat recovery and air-steam separation in the corresponding heat exchanger, so that the recovered heat heats the condensed water entering the final-stage low-pressure heater, thereby being beneficial to energy conservation and consumption reduction.
As one of the preferable schemes, a section of shaft seal of the low-level unit is connected with a shaft seal steam supply main pipe, and the upstream end of the shaft seal steam supply main pipe is connected with an auxiliary steam supply station;
the second-section shaft seal of the low-level unit is connected with a low-level second-section shaft seal steam leakage pipeline, and the downstream end of the low-level second-section shaft seal steam leakage pipeline is connected with a second heat exchanger.
The technical measure is based on the particularity that the high-level unit is only provided with the shaft seal steam leakage system and is not connected with the shaft seal steam supply system arranged on the low-level unit, so that the shaft seal of the low-level unit forms an independent steam supply self-sealing steam shaft seal system, the reliable control of the shaft seal steam supply parameters is facilitated, and the safe operation of the high-level and low-level steam turbine unit is ensured.
The technical measures are based on the steam leakage of the shaft seal of the low-level unit, and the steam leakage is reliably recovered and reused, so that the waste is avoided, the loss is reduced, and the energy conservation and environmental protection performance are good.
Meanwhile, according to the shaft seal system structure, gradient arrangement of the steam seal pressure is formed at the shaft end of the low-level unit, so that steam leakage or air leakage caused by overhigh pressure difference can be reliably prevented, and the shaft seal effect is excellent.
Further, the low-level unit mainly comprises a medium-pressure part and a low-pressure part;
correspondingly, the shaft seal steam supply main pipe mainly comprises a medium-pressure one-section shaft seal steam pipe at the upstream and a low-pressure one-section shaft seal steam supply pipe at the downstream;
the medium-pressure one-section shaft seal steam pipe is used for supplying steam to one-section shaft seal of the medium-pressure part in the start-stop stage and the low-load operation stage of the unit; in the normal operation stage of the unit, the steam is leaked outwards at a section of shaft seal of the medium-pressure part;
the low-pressure one-section shaft seal steam supply pipe is used for supplying steam to one-section shaft seal of the low-pressure part;
a temperature reducing station is connected between the medium-pressure one-section shaft seal steam pipe and the low-pressure one-section shaft seal steam supply pipe, and is used for spraying and reducing the temperature of steam which is conveyed to the low-pressure one-section shaft seal steam supply pipe by the medium-pressure one-section shaft seal steam pipe;
and an overflow station and a safety valve are connected to the shaft seal steam supply main pipe at the upstream of the medium-pressure one-section shaft seal steam pipe.
The technical measures aim at the particularity of the low-level unit comprising the medium-pressure part, so that the shaft seal steam supply pipeline of the low-level unit meets the operation technical conditions of the medium-pressure part (namely, steam is supplied to the medium-pressure shaft seal in the starting, stopping and low-load operation process, and steam is leaked to the shaft seal main pipe in the normal operation process to form the first-supply and second-leakage operation) on the one hand, and meets the operation technical conditions of the low-level part (namely, continuous shaft seal steam supply) on the other hand.
Meanwhile, the steam shaft seal pipeline of the medium-pressure part and the shaft seal steam supply pipeline of the low-pressure part are effectively combined by the technical measures, so that one section of shaft seal steam leakage of the medium-pressure part is conveyed to the low-pressure part, on one hand, the arrangement structure of the shaft seal pipeline is reasonably simplified, and on the other hand, the reasonable utilization of steam, energy conservation and consumption reduction are facilitated.
In addition, through the arrangement of the overflow station and the safety valve, the technical measures can ensure that excessive steam leaked from the medium-pressure part can be reliably leaked out, so that the safe operation of the unit is ensured.
Or the low-level unit mainly comprises a low-pressure part;
correspondingly, the shaft seal steam supply mother pipe is used for supplying steam to a section of shaft seal of the low-pressure part;
the upper reaches department of bearing seal steam supply parent tube is connected with the temperature reduction station, the temperature reduction station is used for carrying out the spray to the steam of the one section bearing seal department of delivering to the low pressure part and reducing the temperature.
The technical measures aim at the particularity that the low-level unit only comprises a low-pressure part, so that a shaft seal steam supply pipeline of the low-level unit meets the operation technical condition (namely continuous shaft seal steam supply) of the low-pressure part.
Further, the arrangement position of the second heat exchanger is close to the low-level unit. The technical measure can directly and greatly shorten the flow of the shaft seal steam leakage pipeline of the low-level unit, is beneficial to simplifying the arrangement structure of the shaft seal steam leakage pipeline of the low-level unit, is beneficial to reducing the flow resistance of steam along the shaft seal steam leakage pipeline, reduces the ineffective temperature drop of the steam, and further ensures the effective recovery and reuse of the shaft seal steam leakage.
Further, the second heat exchanger is a water-steam heat exchanger and is provided with a second water side heat exchange pipeline, the upstream end of the second water side heat exchange pipeline is connected with a condensate pump, and the downstream end of the second water side heat exchange pipeline is connected with a final-stage low-pressure heater;
the top of the second heat exchanger is connected with a second exhaust pipeline, the second exhaust pipeline is connected with a second shaft seal fan, and the second exhaust pipeline is used for exhausting uncondensed gas in the second heat exchanger to the atmosphere;
and a second drainage pipeline is connected to the bottom of the second heat exchanger and is used for draining water in the second heat exchanger.
The technical measures aim at the particularity of the air entrainment of steam leakage at the two-stage shaft seal of the low-level unit, and the steam leakage is subjected to heat recovery and air-steam separation in the corresponding heat exchanger, so that the recovered heat preheats the condensate water entering the final-stage low-pressure heater, thereby being beneficial to energy conservation and consumption reduction.
The beneficial technical effects of the utility model are as follows: the technical measures aim at the particularity of the high-low turbine unit, so that the shaft seal leakage of the high-low turbine unit is irrelevant to the shaft seal steam supply of the low turbine unit, and the shaft seal of the low turbine unit forms a self-sealing steam shaft seal system for independent steam supply, and the steam shaft seal system between the high-low turbine unit is not influenced by elevation between the high-low turbine unit and the low turbine unit, thereby effectively simplifying the shaft seal steam supply pipeline arrangement structure between the high-low turbine unit, reducing the technical difficulty of shaft seal steam supply pipeline arrangement, and reliably controlling the shaft seal steam supply parameters so as to ensure the safe and reliable operation of the shaft seal system of the high-low turbine unit.
According to the technical measures, the shaft seal systems of the corresponding steam seal pressure gradient arrangement structures are respectively formed at the shaft seals of the high-level unit and the low-level unit, so that steam leakage outside/air leakage inside caused by too high pressure difference can be reliably prevented, and the shaft seal effect is excellent.
Drawings
FIG. 1 is a schematic diagram of a steam working flow of a steam turbine unit arranged in a high and low configuration.
Fig. 2 is a schematic structural view of the present utility model.
Fig. 3 is a schematic view of another structure of the present utility model.
The meaning of the symbols in the figures: 1-a high-level unit; 11-a high-position one-section shaft seal steam leakage pipeline; 12-a high-position two-section shaft seal steam leakage pipeline; 13-a first heat exchanger; 14-an exhaust pipeline I; 15-a shaft seal fan I; 16-a first water side heat exchange pipeline; 17-a first drainage pipeline;
2-low-level units; 21-a shaft seal steam supply main pipe; 211-medium pressure one section shaft seal steam pipe; 212-low pressure one-section shaft seal steam supply pipe; 213—overflow station; 214-a safety valve; 215—a desuperheating station; 216-a water side heat exchange pipeline III; 22-a low-level two-section shaft seal steam leakage pipeline; 23-a second heat exchanger; 24-an exhaust pipeline II; 25-a shaft seal fan II; 26-a water side heat exchange pipeline II; 27-a second drainage pipeline; 28-auxiliary steam source steam supply station.
Detailed Description
The utility model relates to a turbine unit, in particular to a shaft seal system for the turbine unit which is arranged in a high-low structure, and the technical scheme of the main body of the utility model is specifically described below by combining a plurality of embodiments. Wherein, the embodiment 1 is combined with the attached drawing in the specification, namely, fig. 2, to clearly and specifically explain the technical scheme of the utility model; example 2 the technical solution of the present utility model will be clearly and specifically explained with reference to the accompanying drawing of the specification, i.e. fig. 3.
It is to be noted here in particular that the figures of the utility model are schematic, which for the sake of clarity have simplified unnecessary details in order to avoid obscuring the technical solutions of the utility model which contribute to the state of the art.
Example 1
Referring to fig. 2, the present utility model includes a high-order unit 1 and a low-order unit 2 arranged in a high-order and low-order configuration.
The high-level unit 1 is a combined structure of a high-pressure cylinder HP and a medium-pressure cylinder IP 1. The low-level unit 2 is a combined structure of a middle pressure cylinder II P2, a low pressure cylinder I LP1 and a low pressure cylinder II LP 2.
The high-pressure cylinder HP shaft end of the high-level unit 1 is provided with a first-section shaft seal structure close to the inner side and a second-section shaft seal structure close to the outer side, and the two-section shaft seal structures form vapor seal pressure gradient arrangement at the shaft end of the high-pressure cylinder HP so as to prevent vapor from leaking outside the atmospheric environment due to overhigh pressure difference. Similarly, the middle pressure cylinder of the high-level unit 1 is provided with a first section of shaft seal structure close to the inner side and a second section of shaft seal structure close to the outer side at the end of the first IP1 shaft.
The sections of shaft seals of the high-level unit 1 are connected with steam leakage pipelines, namely high-level sections of shaft seals 11, and the high-level sections of shaft seals 11 are used for guiding and recycling the leaked steam at the sections of shaft seals. The leaked steam at each section of shaft seal of the high-level unit 1 has higher relative quality and less air doping, so that the downstream end of the leaked steam pipeline 11 of the high-level section of shaft seal is connected with the deaerator, the leaked steam at each section of shaft seal is conveyed to the deaerator, and oxygen and other gases are removed by the deaerator and then directly conveyed to the boiler for reuse. Of course, other heaters may be used instead of the deaerator described above.
And the two sections of shaft seals of the high-level unit 1 are connected with steam leakage pipelines, namely high-level two sections of shaft seals 12, and the high-level two sections of shaft seals 12 are used for guiding and recycling the external steam leakage at the two sections of shaft seals. The leaked steam at each two-section shaft seal of the high-level unit 1 has lower relative quality, has more air doping and is not suitable for being directly sent into a boiler after impurity removal, so that the downstream end of the leaked steam pipeline 12 of the high-level two-section shaft seal is connected with the first heat exchanger 13, and the leaked steam at each two-section shaft seal is sent to the first heat exchanger 13 for heat recovery and reuse.
The first heat exchanger 13 adopts a water-steam heat exchange structure, steam is supplied to steam condensation by a steam side heat exchange loop, and the water side heat exchange loop is provided with a water side heat exchange pipeline 16. The upstream end of the first water side heat exchange pipeline 16 is connected with a condensate pump, and the downstream end of the first water side heat exchange pipeline is connected with a final low-pressure heater, so that cooled condensate is conveyed to the final low-pressure heater after heat exchange with steam, and the condensate entering the final low-pressure heater is preheated. At the top of the first heat exchanger 13, an exhaust pipeline 14 is connected, and the first exhaust pipeline 14 is connected with a first shaft seal fan 15, and the first exhaust pipeline 14 is used for outputting and exhausting uncondensed gas in the first heat exchanger 13 to the atmosphere under the action of micro negative pressure suction of the first shaft seal fan 15. At the bottom of the first heat exchanger 13, a first drainage pipeline 17 is connected, and the first drainage pipeline 17 is used for draining steam in the first heat exchanger 13 due to heat exchange; the downstream end of the first drain line 17 is preferably connected to a condenser so that the drain is delivered to the condenser; the first drain pipe 17 is provided with a valve for controlling the on/off state thereof.
The first heat exchanger 13 is arranged near the operation platform of the high-level unit 1 to shorten the steam leakage pipeline and reduce the steam temperature drop. On the premise of not influencing the safe operation of the high-level unit 1, the first heat exchanger 13 is as close to the high-level unit 1 as possible.
The shaft end of the middle pressure cylinder II IP2 of the low-level unit 2 is provided with a first-section shaft seal structure close to the inner side and a second-section shaft seal structure close to the outer side, and the two-section shaft seal structures form vapor seal pressure gradient arrangement at the shaft end of the middle pressure cylinder II IP2 so as to prevent vapor from leaking to the atmosphere due to overhigh pressure difference.
The shaft ends of the first low-pressure cylinder LP1 and the second low-pressure cylinder LP2 of the low-level unit 2 are respectively provided with a first-section shaft seal structure close to the inner side and a second-section shaft seal structure close to the outer side, and the two-section shaft seal structures form vapor seal pressure gradient arrangement at the shaft ends corresponding to the low-pressure cylinders so as to prevent the atmospheric leakage into the cylinders caused by overhigh pressure difference.
And the two-section shaft seals of the low-level unit 2 are connected with steam leakage pipelines, namely, low-level two-section shaft seal steam leakage pipelines 22, and the low-level two-section shaft seal steam leakage pipelines 22 are used for guiding and recycling the external steam leakage at the two-section shaft seals. The leaked steam at each two-stage shaft seal of the low-level unit 2 has lower relative quality, has more air doping and is not suitable for being directly sent into a boiler after impurity removal, so that the downstream end of the leaked steam pipeline 22 of the low-level two-stage shaft seal is connected with the heat exchanger II 23, and the leaked steam at each two-stage shaft seal is sent to the heat exchanger II 23 for heat recovery and reuse.
The second heat exchanger 23 adopts a water-steam heat exchange structure, steam is supplied to steam condensation by a steam side heat exchange loop, and the water side heat exchange loop is provided with a second water side heat exchange pipeline 26. The upstream end of the second water side heat exchange pipeline 26 is connected with a condensate pump, and the downstream end is connected with a final low-pressure heater, so that cooled condensate is conveyed to the final low-pressure heater after heat exchange with steam, and the condensate entering the final low-pressure heater is preheated. The top of the second heat exchanger 23 is connected with a second exhaust pipeline 24, the second exhaust pipeline 24 is connected with a second shaft seal fan 25, and the second exhaust pipeline 24 is used for outputting and exhausting uncondensed gas in the second heat exchanger 23 to the atmosphere under the action of micro negative pressure suction of the second shaft seal fan 25. A second drainage pipeline 27 is connected to the bottom of the second heat exchanger 23, and the second drainage pipeline 27 is used for draining steam in the second heat exchanger 23 due to heat exchange; the downstream end of the second drain pipe 27 is preferably connected to the condenser so that the drain water is delivered to the condenser; the second hydrophobic pipeline 27 is provided with a valve for controlling the on/off state of the second hydrophobic pipeline.
The second heat exchanger 23 is arranged near the operation platform of the low-level unit 2 to shorten the steam leakage pipeline and reduce the steam temperature drop. On the premise of not influencing the safe operation of the low-level unit 2, the second heat exchanger 23 is as close to the low-level unit 2 as possible.
Because the leaked steam at each section of shaft seal of the high-level unit 1 is recovered into the deaerator, the leaked steam at each second section of shaft seal is recovered into the first heat exchanger 13, and no shaft seal steam supply pipeline is arranged between the leaked steam at each section of shaft seal and the low-level unit 2, and no shaft seal steam supply pipeline is allowed between the leaked steam at each section of shaft seal and the low-level unit 2. Therefore, the shaft seal steam supply pipeline of the low-level unit 2 is additionally arranged through the auxiliary steam supply station 28.
The shaft seal steam supply pipeline of the low-level unit 2 consists of a main pipe, namely a shaft seal steam supply main pipe 21, wherein the upstream end of the shaft seal steam supply main pipe 21 is connected with an auxiliary steam source steam supply station 28, and auxiliary steam is independently supplied to the shaft seal steam supply main pipe by the auxiliary steam source steam supply station 28.
Corresponding to the specificity of the medium pressure part and the low pressure part in the low-level unit 2, the shaft seal steam supply main pipe 21 mainly comprises a medium pressure section shaft seal steam pipe 211 at the upstream and a low pressure section shaft seal steam supply pipe 212 at the downstream. The middle-pressure one-section shaft seal steam pipe 211 is correspondingly connected to each one-section shaft seal at the end of the second IP2 shaft of the middle-pressure cylinder, and the low-pressure one-section shaft seal steam supply pipe 212 is correspondingly connected to each one-section shaft seal at the ends of the first LP1 shaft of the low-pressure cylinder and the second LP2 shaft of the low-pressure cylinder.
The middle pressure one section shaft seal steam pipe 211 has two functions. Firstly, the device is used for supplying steam to a section of shaft seal of the second IP2 of the medium pressure cylinder in the working conditions of starting, stopping and low load operation of the unit. And secondly, in the normal operation working condition of the unit, the unit is used for enabling the steam leakage at the shaft seal of the section of the second IP2 of the medium pressure cylinder, namely, the steam leakage is firstly supplied and then is leaked.
The steam leaking out through the middle pressure one section shaft seal steam pipe 211 has two paths. One is to enter the low-pressure one-section shaft seal steam supply pipe 212 after the temperature is reduced so as to continuously supply steam to the shaft end one-section shaft seal of each low-pressure cylinder. And the other is that the excess steam overflows and is recovered or safely discharged. Therefore, a temperature reducing station 215 is connected between the middle-pressure one-stage shaft seal steam pipe 211 and the low-pressure one-stage shaft seal steam pipe 212, and the temperature reducing station 215 is used for carrying out heat exchange and temperature reduction on the steam which is conveyed to the low-pressure one-stage shaft seal steam pipe 212 by the middle-pressure one-stage shaft seal steam pipe 211 according to low-pressure shaft seal control parameters.
The temperature reducing station 215 is connected with a water side heat exchange pipeline III 216 for carrying out water spray temperature reduction on the steam. The second water side heat exchange pipeline 216 is connected with a spraying structure in the temperature reduction station, and cooling water is sprayed in the temperature reduction station 215 by the spraying structure and discharged outside the drain pipe of the temperature reduction station 215. The upstream end of the water side heat exchange line three 216 is connected to a condensate pump for delivering cooled condensate to the attemperation station 215.
An overflow station 213 and a safety valve 214 are connected to the gland supply header 21 upstream of the intermediate pressure stage gland steam pipe 211, and the overflow station 213 and the safety valve 214 are downstream of the auxiliary source supply station 28. The overflow station 213 delivers excess steam from the intermediate pressure shaft seal steam pipe 211 to the low pressure heater. The relief valve 214 serves to prevent over pressurization of the steam within the shaft seal steam feed header 21.
Therefore, the high-level unit 1 and the low-level unit 2 correspond to two sets of shaft seal systems which are basically independent of each other, namely, a shaft seal steam leakage pipeline of the high-level unit 1 and a shaft seal steam supply pipeline of the low-level unit 2 are basically kept independent of each other, and the pipeline flow of the shaft seal system of the whole unit is not influenced by elevation between the high-level unit 1 and the low-level unit 2.
Example 2
Referring to fig. 3, the present utility model includes a high-order unit 1 and a low-order unit 2 arranged in a high-order and low-order configuration.
The high-level unit 1 is a combined structure of a high-pressure cylinder HP and a medium-pressure cylinder IP. The low-level unit 2 is a combined structure of a first low-pressure cylinder LP1 and a second low-pressure cylinder LP 2.
The high-pressure cylinder HP shaft end of the high-level unit 1 is provided with a first-section shaft seal structure close to the inner side and a second-section shaft seal structure close to the outer side, and the two-section shaft seal structures form vapor seal pressure gradient arrangement at the shaft end of the high-pressure cylinder HP so as to prevent vapor from leaking outside the atmospheric environment due to overhigh pressure difference. Similarly, the middle pressure cylinder IP shaft end of the high-level unit 1 is provided with a first section of shaft seal structure close to the inner side and a second section of shaft seal structure close to the outer side.
The sections of shaft seals of the high-level unit 1 are connected with steam leakage pipelines, namely high-level sections of shaft seals 11, and the high-level sections of shaft seals 11 are used for guiding and recycling the leaked steam at the sections of shaft seals. The leaked steam at each section of shaft seal of the high-level unit 1 has higher relative quality and less air doping, so that the downstream end of the leaked steam pipeline 11 of the high-level section of shaft seal is connected with the deaerator, and the leaked steam at each section of shaft seal is conveyed to the deaerator, and is conveyed to the boiler for reuse after oxygen and other gases are removed by the deaerator. Of course, other heaters may be used instead of the deaerator described above.
And the two sections of shaft seals of the high-level unit 1 are connected with steam leakage pipelines, namely high-level two sections of shaft seals 12, and the high-level two sections of shaft seals 12 are used for guiding and recycling the external steam leakage at the two sections of shaft seals. The leaked steam at each two-section shaft seal of the high-level unit 1 has lower relative quality, has more air doping and is not suitable for being directly sent into a boiler after impurity removal, so that the downstream end of the leaked steam pipeline 12 of the high-level two-section shaft seal is connected with the first heat exchanger 13, and the leaked steam at each two-section shaft seal is sent to the first heat exchanger 13 for heat recovery and reuse.
The first heat exchanger 13 adopts a water-steam heat exchange structure, steam is supplied to steam condensation by a steam side heat exchange loop, and the water side heat exchange loop is provided with a water side heat exchange pipeline 16. The upstream end of the first water side heat exchange pipeline 16 is connected with a condensate pump, and the downstream end of the first water side heat exchange pipeline is connected with a final low-pressure heater, so that cooled condensate is conveyed to the final low-pressure heater after heat exchange with steam, and the condensate entering the final low-pressure heater is preheated. At the top of the first heat exchanger 13, an exhaust pipeline 14 is connected, and the first exhaust pipeline 14 is connected with a first shaft seal fan 15, and the first exhaust pipeline 14 is used for outputting and exhausting uncondensed gas in the first heat exchanger 13 to the atmosphere under the action of micro negative pressure suction of the first shaft seal fan 15. At the bottom of the first heat exchanger 13, a first drainage pipeline 17 is connected, and the first drainage pipeline 17 is used for draining steam in the first heat exchanger 13 due to heat exchange; the downstream end of the first drain line 17 is preferably connected to a condenser so that the drain is delivered to the condenser; the first drain pipe 17 is provided with a valve for controlling the on/off state thereof.
The first heat exchanger 13 is arranged near the operation platform of the high-level unit 1 to shorten the steam leakage pipeline and reduce the steam temperature drop. On the premise of not influencing the safe operation of the high-level unit 1, the first heat exchanger 13 is as close to the high-level unit 1 as possible.
The shaft ends of the low-pressure cylinder one LP1 and the low-pressure cylinder two LP2 of the low-level unit 2 are respectively provided with a section of shaft seal structure close to the inner side and a section of shaft seal structure close to the outer side, and the two sections of shaft seal structures form vapor seal pressure gradient arrangement at the shaft ends corresponding to the low-pressure cylinder so as to prevent the atmospheric leakage into the cylinder caused by overhigh pressure difference.
And the two-section shaft seals of the low-level unit 2 are connected with steam leakage pipelines, namely, low-level two-section shaft seal steam leakage pipelines 22, and the low-level two-section shaft seal steam leakage pipelines 22 are used for guiding and recycling the external steam leakage at the two-section shaft seals. The leaked steam at each two-stage shaft seal of the low-level unit 2 has lower relative quality, has more air doping and is not suitable for being directly sent into a boiler after impurity removal, so that the downstream end of the leaked steam pipeline 22 of the low-level two-stage shaft seal is connected with the heat exchanger II 23, and the leaked steam at each two-stage shaft seal is sent to the heat exchanger II 23 for heat recovery and reuse.
The second heat exchanger 23 adopts a water-steam heat exchange structure, steam is supplied to steam condensation by a steam side heat exchange loop, and the water side heat exchange loop is provided with a second water side heat exchange pipeline 26. The upstream end of the second water side heat exchange pipeline 26 is connected with a condensate pump, and the downstream end is connected with a final low-pressure heater, so that cooled condensate is conveyed to the final low-pressure heater after heat exchange with steam, and the condensate entering the final low-pressure heater is preheated. The top of the second heat exchanger 23 is connected with a second exhaust pipeline 24, the second exhaust pipeline 24 is connected with a second shaft seal fan 25, and the second exhaust pipeline 24 is used for outputting and exhausting uncondensed gas in the second heat exchanger 23 to the atmosphere under the action of micro negative pressure suction of the second shaft seal fan 25. A second drainage pipeline 27 is connected to the bottom of the second heat exchanger 23, and the second drainage pipeline 27 is used for draining steam in the second heat exchanger 23 due to heat exchange; the downstream end of the second drain pipe 27 is preferably connected to the condenser so that the drain water is delivered to the condenser; the second hydrophobic pipeline 27 is provided with a valve for controlling the on/off state of the second hydrophobic pipeline.
The second heat exchanger 23 is arranged near the operation platform of the low-level unit 2 to shorten the steam leakage pipeline and reduce the steam temperature drop. On the premise of not influencing the safe operation of the low-level unit 2, the second heat exchanger 23 is as close to the low-level unit 2 as possible.
Because the leaked steam at each section of shaft seal of the high-level unit 1 is recovered into the deaerator, the leaked steam at each second section of shaft seal is recovered into the first heat exchanger 13, and no shaft seal steam supply pipeline is arranged between the leaked steam at each section of shaft seal and the low-level unit 2, and no shaft seal steam supply pipeline is allowed between the leaked steam at each section of shaft seal and the low-level unit 2. Therefore, the shaft seal steam supply pipeline of the low-level unit 2 is additionally arranged through the auxiliary steam supply station 28.
The shaft seal steam supply pipeline of the low-level unit 2 consists of a main pipe, namely a shaft seal steam supply main pipe 21, wherein the upstream end of the shaft seal steam supply main pipe 21 is connected with an auxiliary steam source steam supply station 28, and auxiliary steam is independently supplied to the shaft seal steam supply main pipe by the auxiliary steam source steam supply station 28.
Corresponding to the absence of the medium pressure part in the low-level unit 2, only the specificity of the low pressure part exists, and the shaft seal steam supply main pipe 21 is correspondingly connected to each section of shaft seal at the shaft ends of the first low pressure cylinder LP1 and the second low pressure cylinder LP2 and is used for continuously supplying steam to each section of shaft seal of the low pressure part.
In order to control the steam supply temperature parameters of each section of shaft seal of the low-pressure part, a temperature reducing station 215 is connected to the upstream of the shaft seal steam supply main pipe 21, the temperature reducing station 215 is positioned at the downstream of the auxiliary steam source steam supply station 28 and is used for carrying out heat exchange and temperature reduction on steam which is conveyed to each section of shaft seal by the shaft seal steam supply main pipe 21 according to the low-pressure shaft seal control parameters.
The temperature reducing station 215 is connected with a water side heat exchange pipeline III 216 for carrying out water spray temperature reduction on the steam. The second water side heat exchange pipeline 216 is connected with a spraying structure in the temperature reduction station, and cooling water is sprayed in the temperature reduction station 215 by the spraying structure and discharged outside the drain pipe of the temperature reduction station 215. The upstream end of the water side heat exchange line three 216 is connected to a condensate pump for delivering cooled condensate to the attemperation station 215.
In order to improve the safety, a safety valve 214 is also connected to the upstream of the main shaft seal steam supply pipe 21, the safety valve 214 being downstream of the auxiliary steam supply station 28 and upstream of the temperature reducing station 215. The relief valve 214 serves to prevent over pressurization of the steam within the shaft seal steam feed header 21.
Therefore, the high-level unit 1 and the low-level unit 2 correspond to two sets of shaft seal systems which are basically independent of each other, namely, a shaft seal steam leakage pipeline of the high-level unit 1 and a shaft seal steam supply pipeline of the low-level unit 2 are basically kept independent of each other, and the pipeline flow of the shaft seal system of the whole unit is not influenced by elevation between the high-level unit 1 and the low-level unit 2.
The above examples are only intended to illustrate the present utility model, not to limit it.
Although the utility model has been described in detail with reference to the above embodiments, it will be understood by those of ordinary skill in the art that: the embodiment can be modified or part of the technical characteristics can be replaced equivalently, for example, the cylinder type and arrangement structure of the high-level unit can be a combination of an ultrahigh pressure cylinder, a high pressure cylinder and a medium pressure cylinder; such modifications and substitutions do not depart from the spirit and scope of the utility model.
Claims (9)
1. A shaft seal system of a high-low turbine unit comprises a high-level unit (1) and a low-level unit (2) which are arranged in a high-level structure and a low-level structure;
the method is characterized in that:
the shaft seal steam pipeline of the high-level unit (1) is mutually independent of the shaft seal steam pipeline of the low-level unit (2).
2. The shaft seal system of a high and low steam turbine set according to claim 1, wherein:
the high-level unit (1) is characterized in that a section of shaft seal is connected with a high-level section of shaft seal steam leakage pipeline (11), and the downstream end of the high-level section of shaft seal steam leakage pipeline (11) is connected with a deaerator;
the two-section shaft seal of the high-level unit (1) is connected with a high-level two-section shaft seal steam leakage pipeline (12), and the downstream end of the high-level two-section shaft seal steam leakage pipeline (12) is connected with a first heat exchanger (13).
3. The shaft seal system of a high and low steam turbine set according to claim 2, wherein:
the arrangement position of the first heat exchanger (13) is close to the high-level unit (1).
4. A shaft seal system for a high and low steam turbine set according to claim 2 or 3, wherein:
the first heat exchanger (13) is a water-steam heat exchanger and is provided with a first water side heat exchange pipeline (16), wherein the upstream end of the first water side heat exchange pipeline (16) is connected with a condensate pump, and the downstream end of the first water side heat exchange pipeline is connected with a final low-pressure heater;
an exhaust pipeline I (14) is connected to the top of the heat exchanger I (13), a shaft seal fan I (15) is connected to the exhaust pipeline I (14), and the exhaust pipeline I (14) is used for exhausting uncondensed gas in the heat exchanger I (13) to the atmosphere;
at the bottom of the first heat exchanger (13), a first drainage pipeline (17) is connected, and the first drainage pipeline (17) is used for draining water in the first heat exchanger (13).
5. The shaft seal system of a high and low steam turbine set according to claim 1, wherein:
a shaft seal steam supply main pipe (21) is connected to a shaft seal part of the low-level unit (2), and the upstream end of the shaft seal steam supply main pipe (21) is connected with an auxiliary steam source steam supply station (28);
the two-section shaft seal of the low-level unit (2) is connected with a low-level two-section shaft seal steam leakage pipeline (22), and the downstream end of the low-level two-section shaft seal steam leakage pipeline (22) is connected with a heat exchanger II (23).
6. The shaft seal system of a high and low steam turbine set according to claim 5, wherein:
the low-level unit (2) mainly comprises a medium-pressure part and a low-pressure part;
correspondingly, the shaft seal steam supply main pipe (21) mainly comprises a medium-pressure one-section shaft seal steam pipe (211) at the upstream position and a low-pressure one-section shaft seal steam supply pipe (212) at the downstream position;
the medium-pressure one-section shaft seal steam pipe (211) is used for supplying steam to one-section shaft seal of the medium-pressure part in the start-stop stage and the low-load operation stage of the unit; in the normal operation stage of the unit, the steam is leaked outwards at a section of shaft seal of the medium-pressure part;
the low-pressure one-section shaft seal steam supply pipe (212) is used for supplying steam to one-section shaft seal of the low-pressure part;
a temperature reducing station (215) is connected between the medium-pressure one-section shaft seal steam pipe (211) and the low-pressure one-section shaft seal steam supply pipe (212), and the temperature reducing station (215) is used for spraying and reducing the temperature of steam which is conveyed to the low-pressure one-section shaft seal steam supply pipe (212) by the medium-pressure one-section shaft seal steam pipe (211);
and an overflow station (213) and a safety valve (214) are connected to the shaft seal steam supply main pipe (21) at the upstream of the medium-pressure one-section shaft seal steam pipe (211).
7. The shaft seal system of a high and low steam turbine set according to claim 5, wherein:
the low-level unit (2) mainly comprises a low-pressure part;
correspondingly, the shaft seal steam supply main pipe (21) is used for supplying steam to a section of shaft seal of the low-pressure part;
a temperature reducing station (215) is connected to the upstream of the shaft seal steam supply main pipe (21), and the temperature reducing station (215) is used for spraying water to reduce the temperature of steam at each section of shaft seal which is conveyed to the low-pressure part.
8. The shaft seal system of a high and low steam turbine set according to claim 5, wherein:
the arrangement position of the second heat exchanger (23) is close to the low-level unit (2).
9. The shaft seal system of a high and low steam turbine set according to claim 5 or 8, wherein:
the second heat exchanger (23) is a water-steam heat exchanger and is provided with a second water side heat exchange pipeline (26), the upstream end of the second water side heat exchange pipeline (26) is connected with a condensate pump, and the downstream end of the second water side heat exchange pipeline is connected with a final low-pressure heater;
the top of the second heat exchanger (23) is connected with a second exhaust pipeline (24), the second exhaust pipeline (24) is connected with a second shaft seal fan (25), and the second exhaust pipeline (24) is used for exhausting uncondensed gas in the second heat exchanger (23) to the atmosphere;
and a second drainage pipeline (27) is connected to the bottom of the second heat exchanger (23), and the second drainage pipeline (27) is used for draining water in the second heat exchanger (23).
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202223539367.XU CN219061775U (en) | 2022-12-29 | 2022-12-29 | Shaft seal system of high-low steam turbine unit |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202223539367.XU CN219061775U (en) | 2022-12-29 | 2022-12-29 | Shaft seal system of high-low steam turbine unit |
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| CN219061775U true CN219061775U (en) | 2023-05-23 |
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| CN202223539367.XU Active CN219061775U (en) | 2022-12-29 | 2022-12-29 | Shaft seal system of high-low steam turbine unit |
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