CN-122014361-A - Medium-pressure rotor structure of steam turbine and medium-pressure cylinder steam exhaust parameter control method

CN122014361ACN 122014361 ACN122014361 ACN 122014361ACN-122014361-A

Abstract

The invention discloses a medium-pressure rotor structure of a steam turbine and a method for controlling steam exhaust parameters of a medium-pressure cylinder, and belongs to the technical field of heat and power cogeneration of steam turbines. The medium-pressure rotor structure of the steam turbine comprises a medium-pressure cylinder, a main shaft, a hollow rotor, a clutch, a variable-speed transmission device, a steam extraction port and a control system. The main shaft is arranged in the medium pressure cylinder, and a front-stage movable blade group is arranged on the main shaft; the hollow rotor is coaxially sleeved at the rear part of the main shaft, and a rear-stage movable blade group is arranged on the hollow rotor; the invention realizes continuous and accurate adjustment of exhaust parameters of the medium pressure cylinder by adjusting the rotation speed of the hollow rotor, eliminates the steam impact hazard of a rotary baffle plate, realizes high-quality heat supply, has no additional loss in pure condensation working condition, and has extremely high engineering practical value.

Inventors

LIU SHUAI
ZHANG ZUZHE
YAN CHUANWU
Zuo Chuangju
ZHAO CAI
Sun Yuannan
ZHENG LEI
ZHANG XUEZHI
ZHANG XIAOPING
WANG BO

Assignees

华电电力科学研究院有限公司

Dates

Publication Date: 20260512
Application Date: 20260402

Claims (10)

1. A medium pressure rotor structure for a steam turbine, comprising: A medium pressure cylinder; the main shaft is arranged in the medium-pressure cylinder, and a front-stage movable blade group is sequentially arranged on the main shaft along the axial direction; the hollow rotor is coaxially sleeved on the outer side of the rear part of the main shaft, and a rear-stage movable blade group is arranged on the hollow rotor; The cylinder body penetrating structure is arranged at the steam exhaust end of the medium-pressure cylinder and is used for leading out the rear end of the main shaft and the rear end of the hollow rotor to the outside of the cylinder body; The clutch is arranged outside the medium-pressure cylinder, connected with the rear end of the main shaft and used for controlling the power connection state between the hollow rotor and the main shaft; The variable speed transmission device is arranged outside the medium pressure cylinder, is connected between the main shaft, the clutch and the rear end of the hollow rotor in a transmission manner and is used for driving the hollow rotor to rotate at an adjustable rotating speed; the steam extraction port is arranged in a steam extraction area of the medium pressure cylinder at the downstream of the rear-stage movable blade group and is used for connecting an external heat supply pipe network; And the control system is in signal connection with the clutch and the variable speed transmission device and is used for controlling the engagement and disengagement of the clutch according to the heat supply requirement and controlling the variable speed transmission device to adjust the rotating speed of the hollow rotor.
2. The medium pressure rotor structure of a steam turbine of claim 1, wherein the leading stage bucket group includes stage 1-7 buckets and the trailing stage bucket group includes stage 8 buckets and stage 9 buckets.
3. The medium-pressure rotor structure of a steam turbine according to claim 1, further comprising a built-in support bearing arranged between the front-stage moving blade group and the rear-stage moving blade group and used for supporting the front end of the hollow rotor, wherein the built-in support bearing is a tilting pad bearing or a multi-oil wedge bearing and is provided with a high-temperature-resistant lubricating oil pipeline.
4. The medium-pressure rotor structure of the steam turbine according to claim 1, wherein the connection sequence of the clutch and the variable speed transmission device is that the rear end of the main shaft is sequentially connected with the rear ends of the clutch, the variable speed transmission device and the hollow rotor; Or the rear end of the main shaft is sequentially connected with the variable speed transmission device, the clutch and the rear end of the hollow rotor.
5. The medium pressure rotor structure of a steam turbine according to claim 1, wherein the variable speed transmission means is a gear box or a variable frequency drive motor.
6. The steam turbine intermediate pressure rotor structure of claim 1, wherein the clutch is a synchronous self-shifting clutch or an SSS clutch.
7. The intermediate pressure rotor structure of a steam turbine according to claim 1, wherein a sealing means is provided between the hollow rotor and the main shaft for preventing leakage of steam along a gap therebetween.
8. A steam turbine comprising the intermediate pressure rotor structure of the steam turbine according to any one of claims 1 to 7.
9. A medium pressure cylinder exhaust gas parameter control method based on the steam turbine of claim 8, comprising: receiving an external heat supply load instruction, and determining a required medium pressure cylinder steam exhaust target parameter; According to a preset characteristic model of 'hollow rotor rotating speed-exhaust parameters', calculating a hollow rotor target rotating speed corresponding to the exhaust target parameters of the medium-pressure cylinder; Judging the deviation between the target rotating speed of the hollow rotor and the rated rotating speed of the main shaft: If the target rotating speed of the hollow rotor is equal to the rated rotating speed of the main shaft, the clutch is controlled to be closed, so that the hollow rotor and the main shaft synchronously rotate; If the target rotating speed of the hollow rotor is lower than the rated rotating speed of the main shaft, the clutch is controlled to be disconnected, and the hollow rotor is driven to the target rotating speed through the variable speed transmission device; and monitoring the exhaust parameters of the medium-pressure cylinder in real time, comparing the exhaust parameters with the exhaust target parameters, and carrying out closed-loop correction on the rotating speed of the hollow rotor according to the deviation value until the exhaust parameters are stabilized within the target range.
10. The control method according to claim 9, wherein the rotational speed adjustment range of the hollow rotor is 500rpm to 2800rpm when the target rotational speed of the hollow rotor is lower than the rated rotational speed of the main shaft.

Description

Medium-pressure rotor structure of steam turbine and medium-pressure cylinder steam exhaust parameter control method Technical Field The invention relates to a medium-pressure rotor structure of a steam turbine and a method for controlling steam exhaust parameters of a medium-pressure cylinder, and belongs to the technical field of heat and power cogeneration of steam turbines. Background In cogeneration units, the intermediate pressure cylinders are typically provided with adjustable steam extraction ports to meet industrial or heating demand. There are two main types of conventional adjustment schemes: The first is a rotary baffle type steam extraction structure. The working principle is that the overlapping area of the opening of the disc-shaped baffle plate and the opening of the fixed shell is changed by rotating the disc-shaped baffle plate, so that the flow of steam is throttled and regulated. However, when high pressure, high temperature steam impinges vertically at high velocity on the partially opened rotating barrier planes, severe vertical bounce and turbulence is created. This portion of the rebound steam acts directly on the outlet area of the upstream bucket creating an unstable periodic impact load. Under the working condition of long-term operation, particularly frequent participation in deep peak shaving of a power grid, the high-frequency micro-motion impact can cause micro-motion abrasion of blade roots of the movable blades, induce high-cycle fatigue cracks and seriously threaten the safety of a unit. And the second is punching and extracting steam from the medium-low pressure communicating pipe. The mode directly leads out steam from the middle-low pressure communicating pipe, and the steam has a simple structure, but the steam flows through the later stages (such as the 8 th stage and the 9 th stage) of the middle-pressure cylinder and fully works, so that the pressure and the temperature of the steam are obviously reduced, the heat supply parameters are lower, and the high-quality heat supply requirement cannot be met. In addition, NCB (condensed back) type turbine sets appear in the prior art, and the whole low-pressure cylinder is separated through a clutch, so that direct heat supply of exhaust steam of the medium-pressure cylinder is realized. However, the technology needs to arrange the generator at the machine head, changes the conventional layout of the traditional thermal power generating unit, increases the complexity of plant design and equipment arrangement, is unfavorable for the transformation application of the existing power plant, and has the adjustment object of the whole low-pressure cylinder, so that the fine control of the rear stage of the medium-pressure cylinder can not be realized. Therefore, a new structure is needed that can fundamentally eliminate the vertical impact of steam, and simultaneously achieve high-parameter steam extraction and easy modification. Disclosure of Invention The invention aims to overcome the defects in the prior art, and provides a medium-pressure rotor structure of a steam turbine and a medium-pressure cylinder steam exhaust parameter control method, which can enable the medium-pressure cylinder steam exhaust parameter to meet the heat supply requirement and are safe and reliable to operate. In order to achieve the above purpose, the invention is realized by adopting the following technical scheme: in a first aspect, the present invention provides a medium pressure rotor structure of a steam turbine, comprising: A medium pressure cylinder; the main shaft is arranged in the medium-pressure cylinder, and a front-stage movable blade group is sequentially arranged on the main shaft along the axial direction; the hollow rotor is coaxially sleeved on the outer side of the rear part of the main shaft, and a rear-stage movable blade group is arranged on the hollow rotor; The cylinder body penetrating structure is arranged at the steam exhaust end of the medium-pressure cylinder and is used for leading out the rear end of the main shaft and the rear end of the hollow rotor to the outside of the cylinder body; The clutch is arranged outside the medium-pressure cylinder, connected with the rear end of the main shaft and used for controlling the power connection state between the hollow rotor and the main shaft; The variable speed transmission device is arranged outside the medium pressure cylinder, is connected between the main shaft, the clutch and the rear end of the hollow rotor in a transmission manner and is used for driving the hollow rotor to rotate at an adjustable rotating speed; the steam extraction port is arranged in a steam extraction area of the medium pressure cylinder at the downstream of the rear-stage movable blade group and is used for connecting an external heat supply pipe network; And the control system is in signal connection with the clutch and the variable speed transmission device and is used for controlling the engag