Parallel arrangement and operation mode of main components of steam turbine generator unit based on SSS clutch

Abstract

The invention discloses a steam turbine generator unit component parallel arrangement and operation mode based on an SSS clutch, and belongs to the technical field of thermal power generation. An SSS clutch is used as a core, and main components and corresponding operation modes of the steam turbine generator unit are arranged in a cross-shaped or T-shaped mode. The SSS clutch is provided with three power input ends which are all connected with a steam prime motor; and one output end is connected with the generator. When any one or two prime movers have problems, the one or two prime movers can be stopped in cooperation with a bypass system, and the generator does not need to be separated from a power grid. When the device needs to operate under the straight condensing / extraction condensing working condition, all prime movers work. In winter, a certain input end of the SSS clutch is disengaged, and the low-pressure cylinder does not operate. And one prime motor is arranged between the two water feeding pumps, so that the space can be fully utilized. Due to the fact that the SSS clutch is integrated with a variable gear, the rotating speed of each prime motor can not be 3000 rpm of a conventional single-shaft unit.

Description

Technical Field

[0001] The present invention belongs to the technical field of thermal power generation, and specifically relates to a method of arranging main components of a steam turbine generator set in a T-shape or a cross-shape with an SSS clutch as the core, and a corresponding operation mode. Background Art

[0002] Generally, in the steam turbine plant, two feed water pumps are arranged horizontally near the boiler side. Then, the steam turbine generator set is arranged horizontally towards the switch station.

[0003] Conventional steam turbine generator sets are all single-axis designs, that is, starting from one side, they are arranged in sequence (i.e., in series): high-pressure cylinder, medium-pressure cylinder, low-pressure cylinder, and generator. The bearings of these components are connected with backrest wheels and rotate at the same speed.

[0004] However, the length of the single-shaft steam turbine generator set is too long, which leads to a large length of the steam turbine plant, and the civil engineering investment is also large. In addition, when the bearings of each component are connected with backrest wheels, it is difficult to find the center of the bearing and the workload is large. When designing and building a steam turbine generator set, in order to make the long bearing stable and meet the requirements of axial displacement and expansion difference, some costs need to be paid in various aspects. Therefore, it is beneficial to shorten the length of the steam turbine generator set.

[0005] The conventional layout of coal-fired power plants mostly adopts the arrangement of boiler room, coal bunker room, deaerator room and steam turbine room in sequence, and the steam turbine operating floor elevation is generally 12.6~17 m. In order to improve the utilization efficiency of coal-fired generating units and achieve good economic performance and energy-saving and environmental protection performance of the units, domestic and foreign scholars actively explore the optimization methods of unit equipment layout, such as optimizing the design of steam turbine layout.

[0006] The high-position layout of the steam turbine is to arrange the high-pressure cylinder, medium-pressure cylinder and low-pressure cylinder as a whole close to the top of the boiler (the upper part of the deaerator room and coal bunker room). The 2×660 MW single-reheat ultra-supercritical unit of the third phase of Jinjie Power Plant is the world's first demonstration project of the overall high-position layout of steam turbine generator units and is a typical single-shaft unit.

[0007] The high-low layout of the steam turbine is to arrange the high-pressure cylinder close to the top of the boiler, and the medium-pressure cylinder and the low-pressure cylinder in the conventional steam turbine room. For example, the 1×1350 MW double reheat ultra-supercritical unit of the second phase of Pingshan Power Plant is the world's first demonstration project of high-low layout of steam turbine generator sets and a typical dual-shaft unit.

[0008] Both layout methods can shorten the length of the main steam and reheat steam pipelines, improve the efficiency of coal-fired power generation units, reduce the use of high-temperature pipelines (Note: the overall high-level layout theoretically has greater savings), reduce project costs, and ultimately achieve resource conservation and carbon reduction and pollution reduction.

[0009] Another method is to use SSS clutch (Synchro-Self-Shifting, automatic synchronous clutch).

[0010] The SSS clutch is a fully automatic one-way overrunning clutch that transmits power through gear elements. It can automatically switch according to the speed of the input and output ends: when the input end speeds up relative to the output end, the clutch automatically engages and becomes a gear coupling; when the input end speeds down relative to the output end, the clutch automatically disengages; when disengaged, it is equivalent to two independent rotating devices, and no torque is transmitted to each other.

[0011] In a single-shaft unit with NCB (pure condensing / extracted condensing / back pressure) function, the clutch is generally installed between the low-pressure cylinder and the intermediate-pressure cylinder rotor of the turbine, and the two can be connected or disconnected as needed.

[0012] During the non-heating period, generally in pure condensing conditions or extraction condensing conditions, the SSS clutch engages, and the high, medium and low pressure cylinders of the turbine run together to drive the generator to generate electricity, which can maximize the power generation of the turbine.

[0013] In winter, in order to maximize the heating supply of the unit, that is, the turbine back-pressure operating condition, the SSS clutch is disengaged, the low-pressure cylinder stops dragging (that is, the low-pressure cylinder does not work at this time), and only the high and medium pressure cylinders drive the generator to generate electricity. The exhaust steam of the turbine intermediate pressure cylinder passes through the heating valve, and all the exhaust steam is used for heating the heating network to maximize the heating supply. Summary of the invention

[0014] In order to improve the economic efficiency of the unit, reduce the "non-stop" (i.e., the number of abnormal shutdowns) of the unit, increase the flexibility of operation, and make full use of space, the present invention proposes a method of arranging the main components of the steam turbine generator set in parallel using a cross-shaped SSS clutch.

[0015] The following are the main contents of the invention: In the steam turbine building, two feedwater pumps are arranged horizontally near the boiler side, and then the steam turbine generator set is arranged towards the electrical switch station; The SSS clutch is designed and manufactured in a cross shape, with corresponding disengagement and engagement devices, gears and speed change gears integrated inside, and the transmission ratio may not be 1:1; The cross-shaped SSS clutch has three directions as power input ends, which are defined as "input end 1" for the upper direction input end, "input end 2" for the lower direction input end, and "input end 3" for the left direction input end. The layout of the steam turbine generator set is to use the SSS clutch as the origin, the north direction as the starting point, 90° as the interval, and the high-pressure cylinder, generator, low-pressure cylinder, and medium-pressure cylinder are arranged in a cross shape and clockwise; The power input terminals 1, 2, and 3 of the SSS clutch are connected to the prime mover, namely the high-pressure cylinder, low-pressure cylinder, and medium-pressure cylinder of the steam turbine respectively; The SSS clutch has one output terminal, which is connected to the generator in the right direction; The output end of the SSS clutch is perpendicular to the two input ends 1 and 2, and the transmission ratio can be other than 1:1 through orthogonal gear transmission; The high-pressure cylinder connected to the input terminal 1 of the SSS clutch is arranged vertically between the two horizontal water supply pumps; On the pipeline from medium-pressure exhaust steam to low-pressure cylinder, low-pressure main steam valve and low-pressure regulating steam valve are installed, which can be used to rush the low-pressure cylinder to synchronous speed; The pressurized lubricating oil system of the steam turbine generator set can be used to impulsively or drive the disconnected prime mover to rotate slowly, thus achieving the function of turning the gear; Various equipment, accessories, instruments, etc. required for the thermal system, such as boiler system, high and low pressure bypass system, drain system, high pressure main steam valve and high pressure regulating valve, medium pressure main steam valve and medium pressure regulating valve, etc., are configured according to the conventional configuration and meet the unit operation requirements.

[0016] It can be seen from the above technical solutions that the present invention has the following advantages: If any of the three prime movers of the SSS clutch has a problem or the working conditions require it, it can be shut down from the running system (i.e., not working), and the generator will not be disconnected from the power grid. This will reduce the number of "non-stop" times, avoid greater losses, or improve operational flexibility; By adopting the SSS clutch, the main components of the steam turbine generator set are arranged in cross parallel, which shortens the length of each shaft system, helps to reduce the manufacturing difficulty and cost, improve the bearing stability, and optimize the axial displacement and expansion difference problems; By arranging one prime mover vertically between two horizontal feed water pumps, space can be effectively utilized; In summer, the three input ends of the SSS clutch jointly drive the generator to operate at maximum power generation; in winter, in order to maximize heating, the SSS clutch input end 2 is disengaged, the low-pressure cylinder does not operate; the high-pressure cylinder and the medium-pressure cylinder drive the generator to generate electricity, and the medium-pressure exhaust steam is all used for heating; thus improving the flexibility and economy of operation; By using speed change gears, the speed of each prime mover does not have to be the conventional 3000rpm. Then the high-pressure cylinder can use a model with a speed of 6000rpm or even higher, and the low-pressure cylinder can use a model with a speed of 1500rpm, thereby improving economy. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the technical solution of the present invention, the accompanying drawings required for use in the description will be briefly introduced below. Obviously, the accompanying drawings in the following description are only some embodiments of the present invention. For ordinary technicians in this field, other accompanying drawings can be obtained based on these accompanying drawings without paying creative work.

[0018] Figure 1 Schematic diagram of the main components of a cross-parallel steam turbine generator set based on an SSS clutch.

[0019] Figure 1 Middle: 1- cross-shaped SSS clutch, 2- high-pressure cylinder, 3- medium-pressure cylinder, 4- medium-pressure cylinder exhaust to low-pressure cylinder main steam valve, 5- medium-pressure cylinder exhaust to low-pressure cylinder regulating valve, 6- low-pressure cylinder, 7- generator, 8- #1 feedwater pump, 9- #2 feedwater pump, 10- turbine generator plant (wall). Boiler system, high and low pressure bypass system, high-pressure main steam valve and high-pressure regulating valve, medium-pressure main steam valve and medium-pressure regulating valve are conventional configurations and are not drawn in the figure.

[0020] Figure 2 For the simplified T-shaped layout diagram, the high and medium pressure cylinders are designed as combined cylinders. Please refer to the markings of each device. Figure 1 .

[0021] Figure 3 This is a schematic diagram when the high and medium pressure cylinders are not combined and there are two low pressure cylinders.

[0022] Figure 3 In the middle, 1-cross-shaped SSS clutch, 2-#1 high-pressure cylinder, 2'-#2 high-pressure cylinder, 3-#1 medium-pressure cylinder, 3'-#2 medium-pressure cylinder, 4-#1 low-pressure main steam valve (i.e.: #1 medium-pressure cylinder exhaust to #1 low-pressure cylinder main steam valve), 4'-#2 low-pressure main steam valve (i.e.: #2 medium-pressure cylinder exhaust to #2 low-pressure cylinder main steam valve), 5-#1 medium-pressure cylinder exhaust to #1 low-pressure cylinder regulating valve, 5'-#2 medium-pressure cylinder exhaust to #2 low-pressure cylinder regulating valve, 6-#1 low-pressure cylinder, 6'-#2 low-pressure cylinder, 7-generator, 8-#1 feedwater pump, 9-#2 feedwater pump, 10-steam turbine generator set building (wall). DETAILED DESCRIPTION

[0023] In order to make the purpose, features and advantages of the present invention more obvious and easy to understand, the technical solution of the present invention will be clearly and completely described below in conjunction with the drawings in this specific embodiment. Obviously, the embodiments described below are only part of the embodiments of the present invention, not all of them. Based on the embodiments in this patent, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this patent. Embodiment 1

[0024] The present invention provides a method for arranging the main components of a steam turbine generator set in a cross shape based on an SSS clutch. The main equipment includes: 1-SSS clutch, 2-high-pressure cylinder, 3-medium-pressure cylinder, 4-low-pressure main steam valve (i.e., the main steam valve from the medium-pressure cylinder exhaust to the low-pressure cylinder), 5-low-pressure regulating valve (i.e., the regulating valve from the medium-pressure cylinder exhaust to the low-pressure cylinder), 6-low-pressure cylinder, 7-generator, 8-#1 feedwater pump, 9-#2 feedwater pump, 10-steam turbine generator set plant (wall), such as Figure 1 It should be noted that some thermal equipment, accessories, and instruments, such as the boiler system, bypass system, high-pressure main steam valve, high-pressure regulating valve, medium-pressure main steam valve, medium-pressure regulating valve, supports for various components, thrust bearings, and instruments, are all conventional configurations and are not shown in the figure.

[0025] In the steam turbine plant, two feed water pumps are arranged horizontally near the boiler side (upward), and then the steam turbine generator set is arranged towards the switch station (downward).

[0026] With the cross-shaped SSS clutch as the origin, the four directions are arranged respectively: the high-pressure cylinder in the upper direction, the generator in the right direction, the low-pressure cylinder in the lower direction, and the medium-pressure cylinder in the left direction.

[0027] The cross-shaped SSS clutch has three power input terminals, input terminal 1 is connected to the high-pressure cylinder in the upward direction, input terminal 2 is connected to the low-pressure cylinder in the downward direction, and input terminal 3 is connected to the medium-pressure cylinder in the left direction. These three input terminals can be engaged or disengaged individually.

[0028] The cross-shaped SSS clutch has a power output end, which is connected to the generator in the right direction.

[0029] The input ends 1 and 2 of the SSS clutch are 90 degrees to the output end, so the rotation direction is different, and orthogonal gears are needed to transmit the rotation to achieve the change of direction. Through the speed change gear, the speed of the prime mover can be different from the 3000rpm speed of the conventional steam turbine generator set. For example, the speed of the high-pressure cylinder can be 6000rpm, while the low-pressure cylinder is 1500rpm.

[0030] Such a design has the following advantages.

[0031] First of all, this arrangement improves the safety, economy and operational flexibility of the unit. In reality, the high-pressure cylinder, medium-pressure cylinder and low-pressure cylinder all have the phenomenon of false tripping due to bearing vibration, temperature measurement point problems or other reasons. For units with conventional series arrangement components, all prime movers will be shut down when one cylinder trips. For units using this arrangement structure, with the cooperation of the bypass system, only the prime mover with the problem can be shut down, while the other prime movers continue to run with the generator, which will not cause the "non-stop" phenomenon of the generator being disconnected from the power grid. It is just that the power generation curve assessed by the power grid does not match, which greatly reduces direct economic losses and is also beneficial to various evaluations of power plants. After the problem is solved, open the corresponding high-pressure / medium-pressure / low-pressure main steam valve, and then use the computer to control the high-pressure / medium-pressure / low-pressure regulating valve to open slowly, impulse the rotor, increase the speed, and merge the stopped prime mover into the system for operation. Similarly, the high-pressure cylinder can be exited at low load, and even the medium-pressure cylinder can be exited.

[0032] Secondly, by adopting a cross-shaped arrangement, the length of the shaft system in each direction is reduced. In a short distance in each direction, there are generally four supporting bearings, which actually increases the stability of the bearings. Therefore, the rotor stiffness (i.e., diameter) and material requirements that were originally increased for shaft system stability can be reduced, thereby reducing manufacturing costs and difficulties. In addition, there is only one cylinder in each direction, so axial displacement and expansion differences can be optimized.

[0033] Thirdly, the high-pressure cylinder is arranged vertically between the two horizontal feedwater pumps, which can make full use of the space. Although the low-pressure cylinder is arranged vertically below, according to the conventional unit layout, the space reserved in this direction may not be able to accommodate the low-pressure cylinder, and it needs to be widened toward the switch station. But in general, through this arrangement, the space between the two feedwater pumps can be fully utilized, avoiding a sharp increase in the width of the steam turbine plant. It should be noted that there must be enough space between the high-pressure cylinder and the two feedwater pumps to meet the requirements of fire protection, maintenance, etc.

[0034] Then, this arrangement improves the operating flexibility and economy of the unit: ① During normal operation, the unit operates in a way that maximizes power generation, that is, all three input ends are engaged. ② Through the SSS clutch, the low-pressure cylinder of the steam turbine can be decoupled, so that back-pressure operation can be performed in winter, heat can be supplied to the outside, and the economy of the unit can be improved. ③ For conventional series-type steam turbine generator sets that are not equipped with an SSS clutch, when performing deep peak regulation, that is, when the load of the unit is very low, in order to ensure the safety of the low-pressure cylinder, a certain amount of steam needs to be maintained to cool the low-pressure rotor; and by cutting off the low-pressure cylinder through the SSS clutch, many problems are avoided.

[0035] Finally, the speed gear integrated in the SSS clutch can make the speed of the three prime movers not the conventional 3000rpm. For example, the high-pressure cylinder can use a more efficient 6000rpm or even higher speed. The low-pressure cylinder can use 1500rpm to reduce the difficulty of manufacturing. The medium-pressure cylinder can use 3000rpm, thereby reducing the mechanical loss during gear transmission, and of course, the speed can also be changed. Embodiment 2

[0036] In this embodiment, the cross-shaped arrangement structure is simplified into a T-shaped structure. That is, there is a high- and medium-pressure cylinder, which is arranged vertically between two water pumps. The input end 2 in the lower direction is not connected to the prime mover.

[0037] This method takes up less space overall, and the area occupied by the steam turbine plant can be designed to be smaller. This method is more suitable for units below 300MW. In addition, the speed of the high and medium pressure cylinders can be 3000rpm, or a higher speed can be used through the speed change gear. The speed of the low pressure cylinder is 1500rpm, or 3000rpm without speed change. Embodiment 3

[0038] In this embodiment, the number of low-pressure cylinders is 2, and the high-pressure cylinder and the medium-pressure cylinder are not combined, but the overall arrangement is still cross-shaped.

[0039] This method is suitable for large units. At this time, the speed can be kept unchanged, and the speed of all prime movers is 3000rpm.

[0040] The above description of the disclosed embodiments enables one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but will conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. Parallel arrangement and operation mode of main components of steam turbine generator set based on SSS clutch, characterized by: The main components are SSS clutch, high pressure cylinder, medium pressure cylinder, low pressure cylinder and generator; With the SSS clutch as the origin and the north direction as the starting point, the high-pressure cylinder, generator, low-pressure cylinder, and medium-pressure cylinder are arranged in a clockwise and cross shape; The SSS clutch is designed and manufactured in a cross shape, with corresponding disengagement and engagement devices, gears and speed change gears integrated inside, and the transmission ratio may not be 1:1; The SSS clutch has 3 power input terminals (Note: when it is arranged in a T-shape, only 2 input terminals are used, or only 2 input terminals are manufactured), and 1 power output terminal; The three input terminals of the SSS clutch can be disengaged or engaged individually; The input terminal 1 (upward direction) of the SSS clutch is connected to the prime mover 1, that is, the high-pressure cylinder; The input terminal 2 (downward direction) of the SSS clutch is connected to the prime mover 2, that is, the low-pressure cylinder; The input terminal 3 (left direction) of the SSS clutch is connected to the prime mover 3, that is, the medium pressure cylinder; The power output end (right direction) of the SSS clutch is connected to the generator; The output end of the SSS clutch is perpendicular to the two input ends 1 and 2, and is driven by orthogonal gears; The prime mover connected to the input terminal 1 of the SSS clutch is arranged vertically between the two water supply pumps; Other thermal systems, equipment, accessories, instruments, etc. are configured in accordance with conventional procedures to meet operational requirements.

2. According to claim 1, it is characterized in that: If any of the three prime movers of the SSS clutch has a problem or the operating conditions require it, it can be disengaged and deactivated from the running system (i.e., not working) without decoupling the generator from the grid.

3. According to claim 1, it is characterized in that: The prime mover connected to the input terminal 1 of the SSS clutch is arranged vertically between the two water pumps, thereby making full use of the space.

4. The method according to claim 1, characterized in that: In summer, or when pure condensation / extraction condensation is required, the three input ends of the SSS clutch are all engaged, and the high, medium and low pressure cylinders all work as prime movers, driving the generator together to operate at maximum power generation. In winter, the input end connected to the low pressure cylinder is disconnected, the low pressure cylinder does not operate, and only the high and medium pressure cylinders drive the generator to generate electricity; and the exhaust steam of the medium pressure cylinder is all used for steam heating.

5. The method according to claim 1, characterized in that: The three power input ends of the SSS clutch can all use gear shifting (Note: the speed change gear is integrated in the SSS clutch), so that the speed of each prime mover can be other than the conventional 3000rpm.

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