Lubricating oil system for high-speed steam turbine generator unit

Abstract

The utility model provides a lubricating oil system for a high-speed steam turbine generator unit, which can be used for the high-speed steam turbine generator unit and is high in operation stability. An inlet of the shaft head oil pump is connected with an outlet of the oil tank through a first pipeline, an outlet of the shaft head oil pump is connected with a second pipeline, and a first branch pipe of the second pipeline is connected with the oil tank. The turbine is a high-speed turbine, the rotating speed of a low-speed shaft of the double-shaft speed change gear box is within the rated rotating speed range of the shaft head oil pump, one end of a rotating shaft of the high-speed turbine is connected with one end of a high-speed shaft of the double-shaft speed change gear box, and one end of a low-speed shaft of the double-shaft speed change gear box is connected with a rotating shaft of the high-speed turbine. And a shaft head oil pump is mounted at the other end of the low-speed shaft of the double-shaft speed change gear box.

Description

Technical Field

[0001] The utility model relates to the technical field of steam turbine generators, in particular to a lubricating oil system for a steam turbine generator set. Background Art

[0002] When the unit is operating normally, lubricating oil is essential to keep the various components of the unit working properly. The bearings of the steam turbine generator set need lubricating oil to form a continuous oil wedge, and the rotor rotates on this oil wedge. Only a small amount of oil is needed to form an oil wedge. However, due to the heat transfer of the rotor, the friction of the bearing surface, and the flow of the lubricating oil itself, a large amount of heat is generated. In order to ensure that the bearing temperature is within a safe range, the steam turbine generator set can be shut down smoothly and safely, and save factory electricity, it is necessary to continuously provide excessive flowing lubricating oil to the bearing for cooling, otherwise it will cause accidents such as oil shortage and tile burning of the steam turbine generator set. Therefore, a stable and reliable lubricating oil supply method is needed to reduce the risk of failure and improve the reliability of the unit, which requires a stable and reliable oil supply system to continuously deliver lubricating oil to the steam turbine generator set.

[0003] The existing oil supply system is as follows Figure 1 As shown, a lubricating oil system for a steam turbine generator set comprises an oil tank 3, an axial head oil pump 4, a steam turbine 1 and a generator 2, wherein the rear end of the rotating shaft of the steam turbine 1 is connected to the generator 2, the front end of the rotating shaft of the steam turbine 1 is equipped with the axial head oil pump 4, the inlet of the axial head oil pump 4 is connected to the outlet of the oil tank 3 through a first pipeline 12, the outlet of the axial head oil pump 4 is connected to a second pipeline 13, the second pipeline 13 is divided into two branches, the first branch 131 of the second pipeline 13 is connected to the oil tank 3, the first branch 1321 and the second branch 132 of the second pipeline 13 are connected to the oil tank 3, and the second branch 132 of the second pipeline 13 is connected to the oil tank 3. The pipe 1322 and the third branch pipe 1323 are respectively connected to the lubricating oil port at the front end of the steam turbine 1, the lubricating oil port at the rear end of the steam turbine 1 and the lubricating oil port at the rear end of the generator 2; the second pipeline 13 is provided with an oil cooler 8 before the branch pipe is separated, and the second branch pipe 132 of the second pipeline 13 is provided with a check valve 9, an oil pressure regulator 10 and an oil filter 11; the oil tank 3 is respectively connected to the lubricating oil port at the front end and the lubricating oil port at the rear end of the steam turbine 1 and the lubricating oil port at the rear end of the generator 2 through the first branch pipe 141, the second branch pipe 142 and the third branch pipe 143 of the third pipeline 14.

[0004] It also includes a DC gear oil pump 5, an AC gear oil pump 6 and an AC electric oil pump 7, the inlets of the DC gear oil pump 5, the AC gear oil pump 6 and the AC electric oil pump 7 are connected to the oil tank 3 through pipelines, and the outlets of the DC gear oil pump 5, the AC gear oil pump 6 and the AC electric oil pump 7 are connected to the second pipeline 13 through pipelines.

[0005] This oil supply system installs the shaft head oil pump at the front end of the rotating shaft of the steam turbine, which is driven by the mechanical transmission of the steam turbine. When the steam turbine operates, it drives the shaft head oil pump to operate, ensuring that the shaft head oil pump continuously pumps lubricating oil during the operation of the steam turbine. When the shaft head oil pump fails, the DC gear oil pump 5, the AC gear oil pump 6, and the AC motor-driven oil pump 7 can be started as standby oil pumps to transport lubricating oil to the unit, and the operation is stable and reliable.

[0006] High-speed steam turbines (with a rotational speed of 3000 revolutions per minute and above) have been widely used due to their high efficiency, strong stability, high energy density, and relatively light self-weight. Therefore, more and more steam turbine generator sets adopt high-speed steam turbines. However, for the lubricating oil system for steam turbine generator sets described above, the rated rotational speed of the shaft head oil pump used is below 3000 revolutions per minute, while the rotational speed of high-speed steam turbines is above 3000 revolutions per minute. The shaft head oil pump cannot be installed on the rotating shaft of the high-speed steam turbine, resulting in this lubricating oil system being only applicable to low-speed steam turbine generator sets and not applicable to high-speed generator sets. Currently, the lubricating oil system used in high-speed steam turbine generator sets does not have a shaft head oil pump, only a DC gear oil pump, an AC gear oil pump, and an AC motor-driven oil pump. These oil pumps are controlled by an automated control system rather than by the mechanical transmission of the steam turbine, and cannot ensure that they must start when the steam turbine operates. Once there is a deviation in the control system, it will cause insufficient lubricating oil, resulting in the steam turbine running out of oil and burning the bearings, and the stability of the system operation is low. Summary of the Invention

[0007] Aiming at the disadvantages of the existing lubricating oil system for steam turbine generator sets, which is not applicable to high-speed steam turbine generator sets and has low system operation stability, the present invention provides a lubricating oil system for high-speed steam turbine generator sets, which can be used for high-speed steam turbine generator sets and has high system operation stability.

[0008] A lubricating oil system for a high-speed steam turbine generator set, which includes an oil tank, a shaft head oil pump, a steam turbine, a generator and a shaft head oil pump. The inlet of the shaft head oil pump is connected to the outlet of the oil tank through a first pipeline, the outlet of the shaft head oil pump is connected to a second pipeline, a first branch pipe of the second pipeline is connected to the oil tank, a part of the second pipeline before the branch pipe is provided with an oil cooler, and a second branch pipe of the second pipeline is provided with a check valve, an oil pressure regulator and a filter; it also includes a DC gear oil pump, an AC gear oil pump and an AC motor-driven oil pump. The inlets of the DC gear oil pump, the AC gear oil pump and the AC motor-driven oil pump are respectively connected to the oil tank through pipelines, and the outlets of the DC gear oil pump, the AC gear oil pump and the AC motor-driven oil pump are respectively connected to the second pipeline through pipelines; it is characterized in that: it also includes a two-shaft variable-speed gearbox. The steam turbine is a high-speed steam turbine. The rotational speed of the slow shaft of the two-shaft variable-speed gearbox is within the rated rotational speed range of the shaft head oil pump. One end of the rotating shaft of the high-speed steam turbine is connected to one end of the high-speed shaft of the two-shaft variable-speed gearbox. One end of the low-speed shaft of the two-shaft variable-speed gearbox is connected to the rotating shaft of the high-speed steam turbine. The other end of the slow shaft of the two-shaft variable-speed gearbox is installed with the shaft head oil pump. The outlet of the shaft head oil pump is connected to the second pipeline. A first branch pipe of the second pipeline is connected to the oil tank. The second branch pipe of the second pipeline is divided into four branch pipes. The first branch pipe, the second branch pipe, the third branch pipe, the fourth branch pipe and the fifth branch pipe of the second branch pipe of the second pipeline are respectively connected to the lubricating oil ports at the front end of the high-speed steam turbine, the lubricating oil ports at the rear end of the steam turbine, the lubricating oil port of the two-shaft variable-speed gearbox, the lubricating oil ports at the front end of the generator and the lubricating oil ports at the rear end of the generator; the oil tank is respectively connected to the lubricating oil ports at the front end of the high-speed steam turbine, the lubricating oil ports at the rear end of the high-speed steam turbine, the lubricating oil port of the two-shaft variable-speed gearbox, the lubricating oil ports at the front end of the generator and the lubricating oil ports at the rear end of the generator through the first branch pipe, the second branch pipe, the third branch pipe, the fourth branch pipe and the fifth branch pipe of the third pipeline.

[0009] After adopting the above structure of the present utility model, the steam turbine is connected to the generator through a two-shaft variable-speed gearbox instead of directly connecting to the generator. One end of the low-speed shaft of the two-shaft variable-speed gearbox is connected to the generator, and an oil head pump is installed at the other end. The oil head pump is coaxially driven with the generator, so that the oil head pump can be applied to high-speed steam turbine generator sets under the condition of meeting the rated speed. When the generator operates, the oil head pump can be driven to operate together, ensuring that the oil head pump operates simultaneously when the steam turbine generator set operates, continuously delivering lubricating oil to the unit, and ensuring the stability of the system. The five branch pipes of the second branch pipe of the second pipeline are respectively connected to the lubricating oil ports at the front end of the high-speed steam turbine, the lubricating oil ports at the rear end of the high-speed steam turbine, the lubricating oil port of the two-shaft variable-speed gearbox, the lubricating oil port at the front end of the generator, and the lubricating oil port at the rear end of the generator, ensuring that the lubricating oil can be delivered to every position of the unit and improving the operation stability of the unit. The five branch pipes of the third pipeline are connected to the oil tank and the lubricating oil ports at the front end of the high-speed steam turbine, the lubricating oil ports at the rear end of the high-speed steam turbine, the lubricating oil port of the two-shaft variable-speed gearbox, the lubricating oil port at the front end of the generator, and the lubricating oil port at the rear end of the generator, enabling the excess lubricating oil of the unit to flow out in time, ensuring the fluidity of the lubricating oil, and further improving the operation stability of the unit. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 is a schematic structural diagram of the prior art;

[0011] Figure 2 is a schematic structural diagram of the present utility model. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0012] A lubricating oil system for a high-speed steam turbine generator set includes an oil tank 3, an oil head pump 4, a steam turbine 16, a generator 2, and an oil head pump 4. The inlet of the oil head pump 4 is connected to the outlet of the oil tank 3 through a first pipeline 12, and the outlet of the oil head pump 4 is connected to a second pipeline 13. The first branch pipe 131 of the second pipeline 13 is connected to the oil tank 3. A cooler 8 is provided in the part of the second pipeline 13 before the branch pipes are separated. The second branch pipe 132 of the second pipeline 13 is provided with a check valve 9, an oil pressure regulator 10, and a filter 11.

[0013] The cooler 8 is used to adjust the temperature of the lubricating oil to prevent the unit from overheating; the check valve 9 is used to prevent the reverse flow of the lubricating oil; the filter 11 is used to filter impurities in the lubricating oil; the oil pressure regulator 10 is used to adjust the oil pressure of the lubricating oil to keep the oil pressure within a reasonable range at all times, ensuring the normal operation of the system.

[0014] It also includes a DC gear oil pump 5, an AC gear oil pump 6 and an AC electric oil pump 7. The inlets of the DC gear oil pump 5, the AC gear oil pump 6 and the AC electric oil pump 7 are respectively connected to the oil tank 3 through pipelines, and the outlets of the DC gear oil pump 5, the AC gear oil pump 6 and the AC electric oil pump 7 are respectively connected to the second pipeline 13 through pipelines. The DC gear oil pump 5, the AC gear oil pump 6 and the AC electric oil pump 7 are used to supply oil to the unit as a backup when the shaft head oil pump 4 fails.

[0015] It also includes a two-shaft speed-changing gearbox 15. The steam turbine 16 is a high-speed steam turbine. The rotational speed of the low-speed shaft 151 of the two-shaft speed-changing gearbox 15 is within the rated rotational speed range of the shaft head oil pump 4. One end of the rotating shaft of the high-speed steam turbine 16 is connected to one end of the high-speed shaft 152 of the two-shaft speed-changing gearbox 15. One end of the low-speed shaft 151 of the two-shaft speed-changing gearbox 15 is connected to the rotating shaft of the generator 2. An oil pump 4 is installed at the other end of the low-speed shaft 151 of the two-shaft speed-changing gearbox 15. The outlet of the shaft head oil pump 4 is connected to the second pipeline 13. The first branch pipe 131 of the second pipeline 13 is connected to the oil tank 3. The second branch pipe 132 of the second pipeline 13 branches out into four branch pipes. The first branch pipe 1321, the second branch pipe 1322, the third branch pipe 1323, the fourth branch pipe 1324 and the fifth branch pipe 1325 of the second branch pipe 132 of the second pipeline 13 are respectively connected to the lubricating oil ports at the front end of the high-speed steam turbine 16, the lubricating oil ports at the rear end of the steam turbine 1, the lubricating oil port of the two-shaft speed-changing gearbox 15, the lubricating oil ports at the front end of the generator 2 and the lubricating oil ports at the rear end of the generator 2.

[0016] The oil tank 3 is respectively connected to the lubricating oil ports at the front end of the high-speed steam turbine 16, the lubricating oil ports at the rear end of the high-speed steam turbine 16, the lubricating oil port of the two-shaft speed-changing gearbox 15, the lubricating oil ports at the front end of the generator 2 and the lubricating oil ports at the rear end of the generator 2 through the first branch pipe 141, the second branch pipe 142, the third branch pipe 142, the fourth branch pipe 144 and the fifth branch pipe 145 of the third pipeline 14. The third pipeline 14 is used to transport the redundant lubricating oil back to the oil tank 3 for reuse.

[0017] The working process of the utility model is as follows:

[0018] The high-speed steam turbine 16 starts, driving the high-speed shaft 152 of the two-shaft variable-speed gearbox 15 to rotate at a high speed. Through the speed-changing transmission of the internal structure of the gearbox 15, the low-speed shaft 151 of the two-shaft variable-speed gearbox 15 is driven to rotate at a low speed, and the low-speed shaft 151 drives the shaft head oil pump 4 and the generator 2 to rotate. The rotational speed of the low-speed shaft 151 is within the rated rotational speed range of the shaft head oil pump 4 and the generator 2. The shaft head oil pump 4 pumps the lubricating oil in the oil tank 3 through the first pipeline 12, and then pumps out the lubricating oil through the second pipeline 13. The lubricating oil is transported through the second branch pipe 132 to the lubricating oil ports at the front end of the high-speed steam turbine 16, the lubricating oil ports at the rear end of the steam turbine 1, the lubricating oil ports of the two-shaft variable-speed gearbox 15, the lubricating oil ports at the front end of the generator 2, and the lubricating oil ports at the rear end of the generator 2. The excess lubricating oil in the second pipeline 13 will be transported back to the oil tank 3 through the first branch pipe for recycling. The excess lubricating oil in the two high-speed turbo-generator sets will be transported back to the tank 3 through the third pipeline 14.

[0019] When the shaft head oil pump 4 fails and cannot work or the unit shuts down due to an accident, the DC gear oil pump 5, the AC gear oil pump 6, and the AC motor-driven oil pump 7 start to act as standby oil pumps to transport lubricating oil for the unit.

Claims

1. A lubricating oil system for a high-speed steam turbine generator set, comprising an oil tank, a shaft head oil pump, a steam turbine, a generator and a shaft head oil pump, wherein the inlet of the shaft head oil pump is connected to the outlet of the oil tank through a first pipeline, the outlet of the shaft head oil pump is connected to a second pipeline, the first branch of the second pipeline is connected to the oil tank, the second pipeline is provided with an oil cooler before the branch, and the second branch of the second pipeline is provided with a check valve, an oil pressure regulator and an oil filter; it also comprises a DC gear oil pump, an AC gear oil pump and an AC electric oil pump, the inlets of the DC gear oil pump, the AC gear oil pump and the AC electric oil pump are respectively connected to the oil tank through pipelines, and the outlets of the DC gear oil pump, the AC gear oil pump and the AC electric oil pump are respectively connected to the second pipeline through pipelines; characterized in that: It also includes a double-shaft speed-changing gearbox, the steam turbine is a high-speed steam turbine, the slow shaft speed of the double-shaft speed-changing gearbox is within the rated speed range of the shaft head oil pump, one end of the rotating shaft of the high-speed steam turbine is connected to one end of the high-speed shaft of the double-shaft speed-changing gearbox, one end of the low-speed shaft of the double-shaft speed-changing gearbox is connected to the rotating shaft of the high-speed steam turbine, the other end of the slow shaft of the double-shaft speed-changing gearbox is equipped with the shaft head oil pump, the outlet of the shaft head oil pump is connected to a second pipeline, the first branch of the second pipeline is connected to the oil tank, the second branch of the second pipeline is divided into four branch pipes, the first branch of the second pipeline is connected to the oil tank, the second ... The first branch pipe, the second branch pipe, the third branch pipe, the fourth branch pipe and the fifth branch pipe are respectively connected to the lubricating oil port at the front end of the high-speed steam turbine, the lubricating oil port at the rear end of the steam turbine, the lubricating oil port of the dual-shaft speed gearbox, the lubricating oil port at the front end of the generator and the lubricating oil port at the rear end of the generator; the oil tank is respectively connected to the lubricating oil port at the front end of the high-speed steam turbine, the lubricating oil port at the rear end of the high-speed steam turbine, the lubricating oil port of the dual-shaft speed gearbox, the lubricating oil port at the front end of the generator and the lubricating oil port at the rear end of the generator through the first branch pipe, the second branch pipe, the third branch pipe, the fourth branch pipe and the fifth branch pipe of the third pipeline.

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