A power supply system for low-pressure regulating oil in a steam turbine and its operating method.

Abstract

This invention provides an oil supply system and its operating method for driving low-pressure regulating oil in a steam turbine, aiming to solve the reliability problems of existing low-pressure regulating oil supply systems. In the field of steam turbine drives, this invention, through the installation of a low-pressure regulating oil tank, an oil purification device, a lubricating oil manifold, an overflow pipeline, a replenishment pipeline, and accessories, allows the low-pressure regulating oil tank and the lubricating oil manifold to operate independently and supply oil separately during normal turbine operation. Oil cleanliness is also controlled separately. In particular, the low-pressure regulating oil tank is connected to an independent oil purification device, enabling online oil treatment of the regulating oil source. This invention effectively reduces the risks of contamination and failure in the low-pressure regulating oil supply system, facilitates cleanliness control, improves system reliability, prevents jamming of the servo valve in the regulating component, and allows for separate circulation of lubricating oil and regulating oil, shortening the unit's oil circulation cycle.

Description

Technical Field

[0001] This invention belongs to the field of steam turbine drive, and specifically relates to an oil supply system for driving low-pressure regulating oil in a steam turbine and its working method. Background Technology

[0002] The hydraulic regulating system of industrial or marine drive steam turbines typically uses low-pressure regulating oil, with a pressure usually between 2.0 and 2.5 MPa. Figure 2 The traditional turbine lubricating oil and low-pressure regulating oil integrated supply system shown in the diagram uses a shared oil source system, where both the regulating oil and lubricating oil originate from the lubricating oil system's container tank. However, the lubricating oil passes through multiple turbine components, resulting in numerous system openings and making it prone to problems such as oil emulsification and particulate contamination. This leads to poor reliability of the regulating oil system and affects the safe operation of the unit's control system. Generally, the particle size requirement for regulating oil is no lower than NAS level 6, while the requirement for lubricating oil is no lower than NAS level 8. Control oil has even higher cleanliness requirements and longer flushing cycles. Summary of the Invention

[0003] To address the shortcomings of existing technologies, this invention provides an oil supply system and its operating method for driving low-pressure regulating oil in a steam turbine. This oil supply system separates the low-pressure regulating oil source from the lubricating oil source, forming a closed regulating oil source system. The two systems are connected by a replenishment oil pipe and an overflow oil pipe. Furthermore, considering that the quality requirements for regulating oil are higher than those for lubricating oil, an online oil purification device is installed at the regulating oil source to improve the quality of the regulating oil, thereby solving the reliability problem of the low-pressure regulating oil supply system.

[0004] To achieve the objective of this invention, the technical solution adopted is as follows:

[0005] A low-pressure regulating oil supply system for driving a steam turbine includes a low-pressure regulating oil tank 1, an oil purification device 2, a lubricating oil collection tank 3, an overflow pipe 15, and a replenishment pipe 16; the low-pressure regulating oil tank 1 is connected to the oil purification device 2 to realize the function of independent regulating oil source online oil treatment; the low-pressure regulating oil tank 1 and the lubricating oil collection tank 3 are connected by the overflow pipe (15) and the replenishment pipe (16).

[0006] Furthermore, the low-pressure regulating oil tank 1 is equipped with a regulating oil pump 21; the lubricating oil collection tank 3 is equipped with a lubricating oil pump 19; the overflow pipeline 15 is equipped with a normally open shut-off valve 10; the replenishment oil pipeline 16 is equipped with a check valve 4, a three-way switching valve I 5, a three-way switching valve II 7, a cooling circulating oil pump and cooler assembly 8, and an oil filter 9.

[0007] Furthermore, the low-pressure regulating oil tank 1 is connected to the hydraulic component 22 of the control system via a regulating oil pipeline, which includes a regulating oil return pipeline 11 and a regulating oil inlet pipeline 12; the lubricating oil container tank 3 is connected to the turbine bearing housing 17 via a lubricating oil pipeline, which includes a lubricating oil return pipeline 13 and a lubricating oil inlet pipeline 14.

[0008] Furthermore, the three-way switching valve I5 on the oil replenishment pipeline 16 is connected to the external oil injection port 20. The connecting pipeline is equipped with a normally closed shut-off valve 6. External new oil injection is achieved by adjusting the check valve 4, the three-way switching valve I5 and the normally closed shut-off valve 6.

[0009] Furthermore, the lubricating oil tank 3 is connected to a dual oil filter 18 to achieve the function of independently adjusting the quality of the lubricating oil.

[0010] During normal turbine operation, the low-pressure regulating oil tank 1 and the lubricating oil collection tank 3 are set up independently. The two oil tanks are completely isolated and supply oil to each other. The oil cleanliness is controlled separately. The low-pressure regulating oil tank 1 is connected to an independent oil purification device 2 to realize the online oil treatment function of the regulating oil source.

[0011] Operating method of the oil supply system for low-pressure regulating oil in a steam turbine:

[0012] When the oil level in the low-pressure regulating oil tank 1 is insufficient, the oil replenishment pipe 16 is connected to the low-pressure regulating oil tank 1, so that the lubricating oil in the lubricating oil collection tank 3 is replenished to the low-pressure regulating oil tank 1 through the oil replenishment pipe 16; when the low-pressure regulating oil tank 1 is full, the lubricating oil can overflow to the lubricating oil collection tank 3 through the overflow pipe 15; the low-pressure regulating oil tank 1 is connected to an independent oil purification device 2 for online oil source regulation.

[0013] Furthermore, when the oil level in the low-pressure regulating oil tank 1 is insufficient in the above working method, the three-way switching valve II7 on the oil replenishment pipeline is adjusted to connect the oil replenishment pipeline 16 with the cooling circulation pump and oil cooler assembly 8, so that the lubricating oil in the lubricating oil collection tank 3 is replenished to the low-pressure regulating oil tank 1 through the oil inlet pipeline 14 and the oil replenishment pipeline 16. The lubricating oil is filtered when it passes through the oil filter 9 to meet the cleanliness requirements.

[0014] Furthermore, when the oil level in the low-pressure regulating oil tank 1 is insufficient in the above working method, the normally closed shut-off valve 6 is opened, the three-way switching valve I5 is adjusted to the open state, and the one-way valve 4 is closed, so that the oil replenishment pipeline 16 is connected to the external oil filling port 20, and the new oil filling function is realized without using the lubricating oil collection tank 3.

[0015] Furthermore, when the low-pressure regulating oil tank 1 in the above working method is full of oil, the normally open shut-off valve 10 is opened, and the lubricating oil overflows through the overflow pipe 15 to the lubricating oil return pipe 13 and returns to the lubricating oil collection tank 3.

[0016] For the low-pressure regulating oil supply of fully mechanically hydraulically controlled marine drive turbines, this system can also meet the oil supply requirements of the control components of this type of unit.

[0017] The above technical solution has the following beneficial effects:

[0018] 1. This invention sets up the low-pressure regulating oil source and the lubricating oil source independently, forming a closed regulating oil source system. The lubricating oil tank no longer needs a regulating oil pump and pipeline, reducing the tank volume and simplifying the tank structure. For cases where the quality requirements for the regulating oil are higher than those for the lubricating oil, an online oil purification device is installed in the regulating oil source. Since the two systems operate independently, cleanliness control can be performed according to their respective cleanliness requirements, thus achieving the goal of improving the quality of the regulating oil.

[0019] 2. This invention can effectively reduce the risk of contamination and failure in the regulating oil supply system, facilitate cleanliness control, improve system reliability, prevent jamming of servo valves in regulating components, and enable separate circulation of lubricating oil and regulating oil systems, thus shortening the unit's oil circulation cycle.

[0020] 3. To prevent unit operation accidents caused by leakage in the regulating oil system, a replenishment oil pipe and an overflow oil pipe are installed between the two oil tanks to connect the two systems. The replenishment oil pipe is connected to the cooling circulating oil pump integrated in the regulating oil tank. When the liquid level in the low-pressure regulating oil tank is insufficient, oil is replenished from the lubricating oil inlet header through the cooling circulating oil pump. An external oil filling port is reserved on the replenishment oil pipe, and a normally open shut-off valve is installed on the overflow pipe to meet the requirements of regulating oil overflowing to the lubricating oil tank and prevent oil source leakage. Attached Figure Description

[0021] Figure 1 A schematic diagram of the oil supply system for driving the low-pressure regulating oil of the steam turbine;

[0022] Figure 2 Schematic diagram of a traditional lubricating oil and low-pressure regulating oil supply integrated system;

[0023] In the diagram: 1 Low-pressure regulating oil tank, 2 Oil purification device, 3 Lubricating oil manifold tank, 4 Check valve, 5 Three-way switching valve I, 6 Normally closed shut-off valve, 7 Three-way switching valve II, 8 Cooling circulating oil pump and cooler assembly, 9 Oil filter, 10 Normally open shut-off valve, 11 Regulating oil return pipe, 12 Regulating oil inlet pipe, 13 Lubricating oil return pipe, 14 Lubricating oil inlet pipe, 15 Overflow pipe, 16 Make-up pipe, 17 Turbine bearing housing, 18 Double oil filter, 19 Lubricating oil pump, 20 External oil inlet, 21 Regulating oil pump, 22 Control system hydraulic components, 111 Manifold tank, 112 Regulating oil inlet pipe, 113 Regulating oil return pipe, 114 Lubricating oil inlet pipe, 115 Lubricating oil return pipe, 116 Turbine bearing housing, 117 Control system hydraulic components, 118 Regulating oil pump, 119 Lubricating oil pump. Detailed Implementation

[0024] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be further described in detail below with reference to the accompanying drawings.

[0025] Example 1

[0026] A system for supplying low-pressure regulating oil to a steam turbine and its operating method, such as... Figure 1 As shown, it includes an independent low-pressure regulating oil tank 1, an independent oil purification device 2, a lubricating oil collection tank 3, an oil replenishment pipeline 15, and an oil overflow pipeline 16.

[0027] The low-pressure regulating oil tank 1 and the lubricating oil collection tank 3 are set up independently. During normal turbine operation, the two oil tanks are completely isolated and supply oil to each other. The oil cleanliness is controlled separately. At the same time, the low-pressure regulating oil tank 1 is connected to an independent oil purification device 2 to realize the online oil treatment function of the regulating oil source.

[0028] When the oil level in the low-pressure regulating oil tank 1 is insufficient, adjust the three-way switching valve II7 on the oil replenishment pipeline to connect the oil replenishment pipeline 15 with the cooling circulation pump and oil cooler assembly 8 of the low-pressure regulating oil tank 1. This allows the lubricating oil in the lubricating oil collection tank 3 to replenish the low-pressure regulating oil tank 1 through the lubricating oil inlet pipeline 14 and the oil replenishment pipeline 16. The lubricating oil is filtered when it passes through the oil filter 9 to meet the cleanliness requirements.

[0029] When the low-pressure regulating oil tank 1 is full, the lubricating oil overflows into the lubricating oil return pipe 13 through the overflow pipe 15.

[0030] Example 2

[0031] A method for operating a low-pressure regulating oil supply system for a steam turbine: when the oil level in the low-pressure regulating oil tank 1 is insufficient, adjust the three-way switching valve I5 to the open state, simultaneously open the normally closed shut-off valve 6, close the one-way valve 4, and connect the oil replenishment pipeline 16 to the external oil filling port 20. This allows for the new oil filling function without starting the lubricating oil collection tank 3.

[0032] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A system for supplying low-pressure regulating oil to a steam turbine, characterized in that: It includes a low-pressure regulating oil tank (1), an oil purification device (2), a lubricating oil collection tank (3), an overflow pipe (15), and a replenishment pipe (16); the low-pressure regulating oil tank (1) is independently connected to the oil purification device (2); the low-pressure regulating oil tank (1) and the lubricating oil collection tank (3) are connected by the overflow pipe (15) and the replenishment pipe (16); The low-pressure regulating oil tank (1) is equipped with a regulating oil pump (21); The lubricating oil container (3) is equipped with a lubricating oil pump (19); The overflow pipeline (15) is equipped with a normally open shut-off valve (10); the oil replenishment pipeline (16) is equipped with a check valve (4), a three-way switching valve I (5), a three-way switching valve II (7), a cooling circulating oil pump and oil cooler assembly (8), and an oil filter (9); the three-way switching valve I (5) is connected to the external oil inlet (20), and the connecting pipeline is equipped with a normally closed shut-off valve (6); The low-pressure regulating oil tank (1) is connected to the hydraulic system component (22) via a regulating oil pipeline, the regulating oil pipeline including a regulating oil return pipeline (11) and a regulating oil inlet pipeline (12); the lubricating oil collection tank (3) is connected to the turbine bearing housing (17) via a lubricating oil pipeline, the lubricating oil pipeline including a lubricating oil return pipeline (13) and a lubricating oil inlet pipeline (14). The lubricating oil tank (3) is connected to a double oil filter (18).

2. A method for operating the oil supply system for driving low-pressure regulating oil of a steam turbine as described in claim 1, characterized in that: When the oil level in the low-pressure regulating oil tank (1) is insufficient, the oil replenishment pipe (16) is connected to the low-pressure regulating oil tank (1), so that the lubricating oil in the lubricating oil collection tank (3) is replenished to the low-pressure regulating oil tank (1) through the oil replenishment pipe (16); when the low-pressure regulating oil tank (1) is full, the lubricating oil can overflow to the lubricating oil collection tank (3) through the overflow pipe (15); the low-pressure regulating oil tank (1) is connected to an independent oil purification device (2) for online oil source regulation.

3. The operating method of the oil supply system for driving the low-pressure regulating oil of the steam turbine according to claim 2, characterized in that: The connection between the oil replenishment pipe (16) and the low-pressure regulating oil tank (1) is achieved by adjusting the three-way switching valve II (7) to connect the oil replenishment pipe (16) with the cooling circulating oil pump and the cooler assembly (8), so that the lubricating oil is replenished to the low-pressure regulating oil tank (1) through the oil inlet pipe (14) and the oil replenishment pipe (16). When the lubricating oil passes through the oil filter (9), it is filtered to meet the cleanliness requirements.

4. The operating method of the oil supply system for driving the low-pressure regulating oil of the steam turbine according to claim 2, characterized in that: When the low-pressure regulating oil tank (1) is full, the normally open shut-off valve (10) is opened to allow the lubricating oil to overflow back into the lubricating oil collection tank (3).

5. A method for operating the oil supply system for driving a low-pressure regulating oil in a steam turbine as described in claim 1, characterized in that: When the oil quantity in the low-pressure regulating oil tank (1) is insufficient, open the normally closed shut-off valve (6), adjust the three-way switching valve I (5) to the open state of the external oil filling port (20), close the one-way valve (4), and connect the oil replenishment pipeline (16) with the external oil filling port (20) to realize the filling of new oil.

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