DE202023106981U1 - Energy-saving and safe steam turbine shaft seal condensate drainage system - Google Patents

Abstract

An energy-saving and safe steam turbine shaft seal condensate drainage system, characterized in that it comprises a front drainage line provided on the steam supply main line of the auxiliary steam shaft seal and a steam seal cooler (12) connected to the steam discharge main line of the shaft seal, wherein a front drainage discharge valve is installed on the front drainage line and the steam seal cooler (12) is connected to the shaft seal steam discharge lines of the high pressure cylinder (2) and the low pressure cylinder, respectively.

Description

Field of technology

The present utility model relates to the technical field of steam turbines, in particular to an energy-saving and safe steam turbine shaft seal condensate drainage system.

State of the art

In order to avoid collisions between moving and static parts, corresponding gaps must be left in the steam turbine equipment of thermal power plants. The existence of these gaps will inevitably lead to steam leakage. For this purpose, a sealing device - a steam seal - is additionally installed. According to the position of the steam seal in the steam turbine, it can be divided into three categories: shaft end steam seal (shaft seal for short), partition steam seal and blade steam seal (flow part steam seal). Among them, the function of the shaft seal is to prevent the steam in the cylinder from escaping to the outside. The shaft seal on the outlet side of the low pressure cylinder is to prevent outside air from entering the cylinder. The shaft seal system is generally characterized by a small shaft seal gap, a low main line pressure of the shaft seal and a small steam supply through the shaft seal.

As in 1 As shown, the existing shaft seal system is supplied by auxiliary steam during start-up or light load, while the shaft seal system is supplied by an ultra-high/high pressure self-seal during high load, with a pressure transmitter at the end of the shaft seal regulating the pressure of the shaft seal steam supply line. The shaft seal steam supply line is equipped with a line from the steam condensate and steam condensate expansion body before the electric heater to the shaft seal inlet adjustment damper; the shaft seal steam discharge main line is equipped with two lines from the steam condensate and steam condensate expansion body for high pressure and low pressure respectively.

1. 1. Bei hoher Last schaltet die Wellendichtung von Hilfsdampf auf Selbstabdichtung um. Da der Dampf nicht in die Hilfsdampfzufuhrleitung eintritt, zirkuliert der Dampf nicht, was zu einer anhaltenden Senkung der Dampftemperatur vor der Einstellklappe für den Wellendichtungseinlass führt. Bei niedriger Last wird nach der Vermischung der Wellendichtung mit Hilfsdampf ein Teil des kalten Dampfes vor der Einstellklappe für den Wellendichtungseinlass in jede Lagerkammer eindringen, und die Zähne der Wellendichtung jedes Lagers werden teilweise gekühlt, was die Lebensdauer der Anlage verringert und Schäden an der Anlage verursacht.
2. 2. In der Praxis ist die Dampfablass-Hauptleitung der Wellendichtung aufgrund des unzureichenden Platzangebots höher als die Dampfablass-Zweigleitungen der einzelnen Lagerkammer mit Ultrahochdruck-/Hochdruck, wodurch sich im unteren Teil der Wellendichtungs-Abzweigleitung Wasser ansammelt, was zu einem schlechten Dampfablass der Lager und dem Phänomen des Lagerdampfs führt und die Wahrscheinlichkeit von Wasser im Schmieröl des Hauptmotors erhöht. Um zu verhindern, dass Wasser im Schmieröl des Hauptmotors enthalten ist, ist es notwendig, die Kondensatableitung der Dampfablass-Hauptleitung der Wellendichtung offen zu halten, um das Vorhandensein von Wasser in der Leitung zu vermeiden. Dies führt jedoch dazu, dass die Dampfablass-Hauptleitung der Wellendichtung durch den Dehnkörper für Dampfkondensat direkt mit dem Kondensator verbunden wird, was den Unterdruck an den Lagern erhöht, was zu einer großen Menge Luft im Kondensator führt, das Vakuum der Einheit beeinträchtigt und somit die Effizienz der Einheit beeinträchtigt.

However, the above shaft sealing system has the following problems:

1. 1. At high load, the shaft seal switches from auxiliary steam to self-sealing. Because the steam does not enter the auxiliary steam supply pipe, the steam does not circulate, resulting in a continuous reduction in the steam temperature in front of the shaft seal inlet adjustment door. At low load, after the shaft seal is mixed with auxiliary steam, part of the cold steam in front of the shaft seal inlet adjustment door will enter each bearing chamber, and the shaft seal teeth of each bearing will be partially cooled, which will reduce the service life of the equipment and cause damage to the equipment.
2. 2. In practice, due to insufficient space, the steam discharge main line of the shaft seal is higher than the steam discharge branch lines of the single ultra-high pressure/high pressure bearing chamber, which causes water to accumulate in the lower part of the shaft seal branch line, resulting in poor steam discharge of the bearings and the phenomenon of bearing steam, and increases the possibility of water in the lubricating oil of the main engine. In order to prevent water from being contained in the lubricating oil of the main engine, it is necessary to keep the condensate drain of the steam discharge main line of the shaft seal open to avoid the presence of water in the line. However, this will cause the steam discharge main line of the shaft seal to be directly connected to the condenser through the steam condensate expansion body, which will increase the negative pressure on the bearings, resulting in a large amount of air in the condenser, affecting the vacuum of the unit, and thus affecting the efficiency of the unit.

Abandonment of the utility model

The purpose of the present utility model is to provide an energy-saving and safe steam turbine shaft seal condensate drain system to overcome the above-mentioned deficiencies of the prior art. It can prevent cold steam from entering the shaft seal, causing damage to the equipment. It can also prevent water from being contained in the lubricating oil of the main engine, and at the same time improve the vacuum environment of the condenser and increase the efficiency of the unit.

The purpose of the present utility model can be achieved by the following technical solution: an energy-saving and safe steam turbine shaft seal condensate drainage system comprising a front drainage line provided on the steam supply main line of the auxiliary steam shaft seal and a steam seal cooler connected to the steam discharge main line of the shaft seal, wherein a front drainage discharge valve is installed on the front drainage line and the steam seal cooler is connected to the shaft seal steam discharge lines of the high-pressure cylinder and the low-pressure cylinder, respectively.

Furthermore, the front drainage line is provided between the adjustment flap for the shaft seal inlet and the first expansion body for steam condensate, wherein the front drainage line is conductive when the adjustment flap for the shaft seal inlet is closed.

Furthermore, the front drainage drain valve is particularly a manual valve.

Furthermore, the front drainage drain valve is in particular a controllable valve.

Furthermore, the shaft seal inlet adjustment flap is connected to an electric heater via a connecting line, the electric heater being connected to a first expansion body for steam condensate via a drainage expansion line, the drainage expansion line being connected to the front drainage line.

Furthermore, the front drainage line is connected parallel to the connecting line.

Furthermore, the adjustment flap for the shaft seal inlet and the drainage expansion line are each equipped with a pneumatic valve and the drainage expansion line and the connecting line are each equipped with a temperature transmitter.

Furthermore, the pipe diameter of the front drainage pipe is smaller than the pipe diameter of the connecting pipe and the pipe diameter of the front drainage pipe is equal to the pipe diameter of the drainage expansion pipe.

Furthermore, the first expansion body for steam condensate has a volume of 13 m ³ .

Furthermore, a pneumatic valve and a temperature transmitter are provided between the shaft seal steam discharge lines of the high-pressure cylinder and the low-pressure cylinder and the steam seal cooler.

1. I: In diesem Gebrauchsmuster wird eine vordere Entwässerungsleitung zur Dampfzufuhr-Hauptleitung der Hilfsdampfwellendichtung hinzugefügt, wobei die vordere Entwässerungsleitung zwischen der Einstellklappe für den Wellendichtungseinlass und dem ersten Dehnkörper für Dampfkondensat vorgesehen ist. Die vordere Entwässerungsleitung wird beim Schließen der Einstellklappe für den Wellendichtungseinlass leitfähig sein, was den Dampfdurchfluss erhöhen und sicherstellen kann, dass die Temperatur vor der Einstellklappe für den Dampfeinlass auf einem hohen Niveau gehalten wird, wodurch das Problem der niedrigen Einlassdampftemperatur im Sicherungsrohr der Wellendichtung gelöst wird; beim vorliegenden Gebrauchsmuster wird das Dampfkondensat der Dampfablass-Hauptleitung der Wellendichtung angepasst an den Dampfdichtungskühler angeschlossen und nutzt den vom Dampfablassventilator im Dampfdichtungskühler erzeugten Mikrounterdruck, um das in der Dampfablass-Hauptleitung angesammelte Wasser abzuführen, wodurch einerseits verhindert wird, dass Wasser im Schmieröl des Hauptmotors enthalten ist, und andererseits die Vakuumumgebung des Kondensators sichergestellt wird, um den Wärmeverbrauch der Dampfturbine zu verringern und den Wirkungsgrad der Einheit zu erhöhen.
2. II: Beim vorliegenden Gebrauchsmuster wird den Hoch-/Niedrig-Dampfkondensat an der Dampfablass-Hauptleitung der Dampfturbine angepasst an den Dampfdichtungskühler angeschlossen. Wenn der Dichtungsdampfkühler aktiviert wird, kann er auch die Wärme des Dampfkondensats der Wellendichtung effektiv zurückgewinnen, wodurch weitere Energieeinsparungen und Emissionsreduzierungen erzielt werden.
3. III: Bei der Anwendung des vorliegenden Gebrauchsmusters muss lediglich eine vordere Entwässerungsleitung neu hinzugefügt und das Anschlussdesign angepasst werden. Es kann direkt am vorhandenen Dampfturbinensystem geändert werden und bietet die Vorteile von Komfort und niedrigen Kosten.

The present utility model has the following advantages compared to the prior art:

1. I: In this utility model, a front drainage line is added to the steam supply main line of the auxiliary steam shaft seal, the front drainage line is provided between the shaft seal inlet adjustment flap and the first steam condensate expansion body. The front drainage line will be conductive when the shaft seal inlet adjustment flap is closed, which can increase the steam flow and ensure that the temperature before the steam inlet adjustment flap is kept at a high level, thereby solving the problem of low inlet steam temperature in the shaft seal fuse pipe; in the present utility model, the steam condensate of the steam discharge main line of the shaft seal is adapted to be connected to the steam seal cooler, and uses the micro negative pressure generated by the steam discharge fan in the steam seal cooler to discharge the water accumulated in the steam discharge main line, which on the one hand prevents water from being contained in the lubricating oil of the main engine, and on the other hand ensures the vacuum environment of the condenser to reduce the heat consumption of the steam turbine and increase the unit efficiency.
2. II: In the present utility model, the high/low steam condensate on the steam discharge main line of the steam turbine is appropriately connected to the steam seal cooler. When the seal cooler is activated, it can also effectively recover the heat of the steam condensate of the shaft seal, thereby achieving further energy saving and emission reduction.
3. III: The application of this utility model only needs to newly add a front drainage pipe and adjust the connection design. It can be directly modified on the existing steam turbine system and has the advantages of convenience and low cost.

Short description of the drawings

• 1 shows a schematic representation of the connection of an existing steam turbine shaft seal condensate drainage system;
• 2 shows a schematic representation of the entire system connection of the present utility model;
• 3 shows a schematic representation of the connection of the newly added front drainage pipe in the present utility model;
• 4 shows a schematic representation of the connection of the adapted vapor seal cooler in the present utility model.

Description of the preferred embodiments

The present utility model is described in detail below in conjunction with the accompanying drawings and specific embodiments.

Example

As in the 2 , 3 and 4 As shown, an energy-saving and safe steam turbine shaft seal condensate drainage system comprises a front drainage line (in 2 shown as a purple pipe) and a steam seal cooler 12 connected to the steam discharge main line of the shaft seal (in 3 shown as a purple pipe), with a front drainage drain valve installed on the front drainage line and the steam seal cooler 12 connected to the shaft seal steam drain lines of the high pressure cylinder 2 and the low pressure cylinder (in 3 shown as a green pipe). In particular, the front drainage line is provided between the adjustment flap for the shaft seal inlet and the first expansion body for steam condensate. The front drainage line will be conductive when the adjustment flap for the shaft seal inlet is closed. In the present embodiment, the first expansion body for steam condensate has a volume of 13 m ³ .

In practice, the front drainage drain valve can be a manual valve or a controllable valve. If a manual valve is selected, one way is to open the manual valve after closing the shaft seal inlet adjustment flap to make the front drainage line conductive; another way is to keep the manual valve open, and after closing the shaft seal inlet adjustment flap, open the adjustment flap on the drainage expansion line, which also opens the front drainage line;

When a controllable valve is selected, the status signal of the shaft seal inlet adjustment valve shall be monitored and detected in real time, and the opening or closing of the controllable valve shall be automatically controlled after the closing signal is detected.

Furthermore, the shaft seal inlet adjustment flap is connected to an electric heater 7 via a connecting line, the electric heater 7 being connected to a first expansion body for steam condensate via a drainage expansion line, the drainage expansion line being connected to the front drainage line, the front drainage line being connected in parallel to the connecting line;

The shaft seal inlet adjustment valve and the drainage expansion line are each provided with a pneumatic valve, and the drainage expansion line and the connecting line are each provided with a temperature transmitter; a pneumatic valve and a temperature transmitter are each provided between the shaft seal steam discharge lines of the high-pressure cylinder 2 and the low-pressure cylinder and the steam seal cooler 12. The pipe diameter of the front drainage line is smaller than the pipe diameter of the connecting line, and the pipe diameter of the front drainage line is equal to the pipe diameter of the drainage expansion line.

• Schritt S1: Nach dem Start der Einheit wird der Dampfdichtungskühler 12 in Betrieb genommen, und der Ventilator im Dampfdichtungskühler 12 dient dazu, das Wasser in der Dampfablass-Hauptleitung abzupumpen und gleichzeitig die Vakuumumgebung im Kondensator zu gewährleisten;
• Schritt S2: Abrufen des Statussignals der Einstellklappe für den Wellendichtungseinlass. Die vordere Entwässerungsleitung wird beim Schließen der Einstellklappe für den Wellendichtungseinlass leitfähig sein, um den Dampfdurchfluss zu erhöhen und die Temperatur vor der Einstellklappe für den Wellendichtungseinlass zu steigern.

The working process of the above steam turbine shaft seal condensate drainage system includes:

• Step S1: After the unit is started, the steam seal cooler 12 is put into operation, and the fan in the steam seal cooler 12 is used to pump out the water in the steam discharge main line while ensuring the vacuum environment in the condenser;
• Step S2: Get the status signal of the shaft seal inlet adjustment door. The front drain line will be conductive when the shaft seal inlet adjustment door is closed to increase the steam flow and raise the temperature in front of the shaft seal inlet adjustment door.

In summary, this technical solution, on the one hand, adds a front drainage line in front of the shaft seal inlet adjustment door. When the shaft seal inlet adjustment door is closed, the front drainage line will be conductive to increase the steam flow and keep the temperature in front of the steam inlet adjustment door at a high level, thereby solving the problem of low inlet steam temperature in the shaft seal backup pipe. After the shaft seal inlet adjustment door is opened again, low temperature auxiliary steam can be prevented from entering the bearing and causing damage to the equipment; on the other hand, the high/low steam condensate on the steam discharge main line of the steam turbine is connected to the steam seal cooler 12 through the steam condensate expansion body (connected to the condenser), and uses the micro negative pressure generated by the steam discharge fan in the steam seal cooler 12 to discharge the water accumulated in the steam discharge main line. It not only solves the problem of water accumulation in the steam discharge main line, but also prevents water in the lubricating oil of the main engine and the vacuum problem of the condenser from the root, effectively recovers the heat of the steam condensate of the shaft seal, and achieves further energy saving and emission reduction.

1. (1) Nach dem Öffnen des Dampfkondensats des Dampfeinlassrohrs der Wellendichtung kann die Temperatur vor der Dampfeinlass-Einstelltür lange Zeit über 320 °C gehalten werden, was den Konstruktionsanforderungen entspricht. Die Ersatzleitung vor Ort ist kurz, nur etwa drei Meter, bei einem Rohrdurchmesser von 25 mm. Die Umbaukosten sind gering und können die sichere Betriebszuverlässigkeit der Einheit effektiv erhöhen und verhindern, dass kalter Dampf in die Wellendichtung eindringt und Anlagenschäden verursacht.
2. (2) Der Hoch-/Niedrig-Dampfkondensat an der Dampfablass-Hauptleitung der Dampfturbine wird durch den Dehnkörper für 26m³-Dampfkondensat (verbunden mit dem Kondensator) angepasst an den Dampfdichtungskühler 12 angeschlossen, wodurch einerseits verhindert wird, dass Wasser im Schmieröl des Hauptmotors enthalten ist, und andererseits die Wärme des Dampfkondensats der Wellendichtung effektiv zurückgewonnen und die Temperatur des Kondensats erhöht wird.
3. (3) Nachdem das Dampfkondensat der Dampfablass-Hauptleitung der Wellendichtung vom Kondensator angepasst an den Dampfdichtungskühler 12 angeschlossen wurde, sanken der Gegendruck des Kondensators und die Dampfablasstemperatur erheblich. Die Testvergleichsdaten vor und nach dem Umbau sind in Tabelle 1 aufgeführt. Nach dem Umbau erhöhte sich der Gesamtvakuumgrad des Kondensators um etwa 0,8 kPa und die Dampfablasstemperatur sank um etwa 4 °C, was darauf hindeutet, dass diese Lösung die Vakuumumgebung des Kondensators effektiv verbessern kann.

Tabelle 1 Vakuum- und Dampfablasstemperatur vor und nach der Anpassung des Dampfkondensatableiters der Wellendichtung des Hauptmotors Ereignisse Vor der Anpassung Nach der Anpassung Verbesserung Hochdruck-KondensatorVakuum kPa -97,09/-97,06/-97,17 -97,92/-97,86/-97,53 0,75 kPa Niederdruck-KondensatorVakuum kPa -97,38/-97,27/-97,17 -98,11/-98,05/-97.94 0,78 Dampfablasstemperatur °C 27,94/26,98/28,33 24,1/22,63/24,47 3,85

1. (4) Nach dem Umbau des Dampfkondensatableiters der Wellendichtung wurde der das Kondensatorvakuum deutlich verbessert, der Wärmeverbrauch der Dampfturbine reduziert, der Wirkungsgrad der Einheit weiter verbessert, die Stromversorgungskosten gesenkt, und die wirtschaftlichen Vorteile waren beträchtlich.

To verify the effectiveness of the present technical solution, the present embodiment was tested on an existing turbine system after modification, and the following conclusions were obtained after the test:

1. (1) After opening the steam condensate of the shaft seal steam inlet pipe, the temperature in front of the steam inlet adjustment door can be kept above 320 °C for a long time, which meets the design requirements. The on-site replacement pipe is short, only about three meters, with a pipe diameter of 25 mm. The reconstruction cost is low, and can effectively increase the safe operation reliability of the unit and prevent cold steam from entering the shaft seal and causing equipment damage.
2. (2) The high/low steam condensate on the steam discharge main line of the steam turbine is connected to the steam seal cooler 12 through the 26m ³ steam condensate expansion body (connected to the condenser), which on the one hand prevents water from being contained in the lubricating oil of the main engine, and on the other hand effectively recovers the heat of the steam condensate of the shaft seal and increases the temperature of the condensate.
3. (3) After the steam condensate of the shaft seal steam discharge main line from the condenser was adapted to the steam seal cooler 12, the back pressure of the condenser and the steam discharge temperature decreased significantly. The test comparison data before and after the modification are shown in Table 1. After the modification, the total vacuum degree of the condenser increased by about 0.8 kPa and the steam discharge temperature decreased by about 4 °C, indicating that this solution can effectively improve the vacuum environment of the condenser.

Table 1 Vacuum and steam discharge temperature before and after adjustment of the steam trap of the main engine shaft seal events Before adjustment After adjustment improvement High pressure condenserVacuum kPa -97.09/-97.06/-97.17 -97.92/-97.86/-97.53 0.75 kPa Low pressure condenserVacuum kPa -97.38/-97.27/-97.17 -98.11/-98.05/-97.94 0.78 Steam discharge temperature °C 27.94/26.98/28.33 24.1/22.63/24.47 3.85

1. (4) After the steam trap of the shaft seal was remodeled, the condenser vacuum was significantly improved, the heat consumption of the steam turbine was reduced, the unit efficiency was further improved, the power supply cost was reduced, and the economic benefits were considerable.

List of reference symbols

1

Ultra high pressure cylinder

2

High pressure cylinder

3

Medium pressure cylinder

4

Low pressure cylinder A

5

Low pressure cylinder B

6

Auxiliary steam

7

Electric heater

8th

Shaft seal overflow adjustment flap

9

Shaft seal inlet steam adjustment flap

10

Condensate consumer main line

11

Steam pump shaft seal steam

12

Steam seal cooler

101

To the 26m ³ - expansion body for steam condensate

102

to 13m ³ - expansion body for steam condensate

103

For medium and low pressure connection line

104

To the high pressure condenser

105

To low pressure heating No. 10

106

High discharge

Claims (9)

An energy-saving and safe steam turbine shaft seal condensate drainage system, characterized in that it comprises a front drainage line provided on the steam supply main line of the auxiliary steam shaft seal and a steam seal cooler (12) connected to the steam discharge main line of the shaft seal, wherein a front drainage discharge valve is installed on the front drainage line and the steam seal cooler (12) is connected to the shaft seal steam discharge lines of the high pressure cylinder (2) and the low pressure cylinder, respectively. Energy-saving and safe steam turbine shaft seal condensate drainage system according to Claim 1 , characterized in that the front drainage line is provided between the adjustment flap for the shaft seal inlet and the first expansion body for steam condensate, wherein the front drainage line is conductive when the adjustment flap for the shaft seal inlet is closed. Energy-saving and safe steam turbine shaft seal condensate drainage system according to Claim 1 , characterized in that the front drainage drain valve is in particular a manual valve or a controllable valve. Energy-saving and safe steam turbine shaft seal condensate drainage system according to Claim 2 , characterized in that the adjustment flap for the shaft seal inlet is connected to an electric heater (7) via a connecting line, wherein the electric heater (7) is connected to a first expansion body for steam condensate via a drainage expansion line, wherein the drainage expansion line is connected to the front drainage line. Energy-saving and safe steam turbine shaft seal condensate drainage system according to Claim 4 , characterized in that the front drainage line is connected parallel to the connecting line. Energy-saving and safe steam turbine shaft seal condensate drainage system according to Claim 4 , characterized in that the adjustment flap for the shaft seal inlet and the drainage expansion line are each equipped with a pneumatic valve and the drainage expansion line and the connecting line are each equipped with a temperature transmitter. Energy-saving and safe steam turbine shaft seal condensate drainage system according to Claim 4 , characterized in that the pipe diameter of the front drainage line is smaller than the pipe diameter of the connecting line and the pipe diameter of the front drainage line is equal to the pipe diameter of the drainage expansion line. Energy-saving and safe steam turbine shaft seal condensate drainage system according to Claim 2 , characterized in that the first expansion body for steam condensate has a volume of 13 m ³ . Energy-saving and safe steam turbine shaft seal condensate drainage system according to Claim 1 , characterized in that a pneumatic valve and a temperature transmitter are provided between the shaft seal steam discharge lines of the high-pressure cylinder (2) and the low-pressure cylinder and the steam seal cooler (12).

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