CN-117425766-B - Full-load efficient turbine unit, thermodynamic system and operation method

Abstract

The invention provides a full-load efficient steam turbine unit, a thermodynamic system and an operation method, wherein at least two steam channels (7) are arranged in an adjusting stage (6) at the front end of a high-pressure cylinder (4) along the radial direction, when the thermodynamic system is in different load intervals, the thermodynamic system can be switched to the corresponding steam channels (7) to operate, the different steam channels (7) are utilized to have different steam through-flow capacities and different pressure stages matched with the steam channels in the steam channels to adapt to different load working conditions, the higher circulation efficiency and lower system energy consumption under medium and low load are ensured, the main steam valve (5) and an adjusting valve (51) arranged in the pipeline system are utilized to control the on-off of each steam channel (7), the multi-stage branch steam pipe network is also arranged, the smooth transition can be realized when the different steam channels (7) are switched, the mutation is avoided, the tail end of the adjusting stage (6) is led out of an air extraction pipeline to be connected with an adjustable heater (19) under the medium and low load, the water temperature of the inlet end of a boiler (1) is improved, the denitration temperature is adjusted according to the actual requirements, and the denitration temperature is met.

Inventors

• WANG WEILIANG
• LV JUNFU

Assignees

• 暨南大学
• 清华大学

Dates

Publication Date

20260505

Application Date

20220311

Claims (17)

1. 1. The full-load efficient turbine unit comprises a working cylinder body, wherein the working cylinder body is any one of a high-pressure cylinder, a medium-pressure cylinder and a low-pressure cylinder, a regulating stage is arranged in the working cylinder body, and is characterized in that the regulating stage is provided with at least two steam channels along the radial direction, the front end of the steam channel is connected with at least one regulating valve for controlling the on-off of the steam flow, at least one pressure stage is arranged in at least one steam channel, and each pressure stage consists of a static blade grid positioned at the front end and a movable blade grid positioned at the rear end; each steam channel is provided with at least two configuration parameters, namely the flow area of the steam channel and the number of pressure stages arranged in the steam channel; The number of pressure stages in any one of the steam passages is not less than the number of pressure stages in any one of the steam passages located outside thereof, the steam passage closer to the inner axis has more pressure stages, and when the load is lower, it is switched to the steam passage having more pressure stages.
2. 2. The full-load high-efficiency turbine set of claim 1, wherein at least one of the steam channels is provided with no static blade cascade or no static blade cascade with constant axial flow area, and no moving blade cascade or no reaction moving blade cascade.
3. 3. The full load high efficiency turbine assembly of claim 1, wherein at least one pair of vane cascades in adjacent steam channels are radially connected, the vane cascades defining a radial connection are a vane cascade pair, the vane cascade pair forming a circumferentially extending annular vane cascade spacer at the connection, the annular vane cascade spacer being connected to the end of the spacer wall adjacent the steam channels.
4. 4. The full-load efficient turbine unit of claim 1, wherein the vane cascade extends directly to an innermost steam channel or through a partition plate, and the partition plate is provided with a first steam through hole in a flow area corresponding to each steam channel.
5. 5. A full load high efficiency turbine engine set according to claim 3, wherein at least one pair of radially connected rotor blade cascades adjacent said steam path are defined as a pair of rotor blade cascades which form a circumferentially extending annular rotor blade cascade spacer at the connection.
6. 6. The full-load efficient turbine unit according to claim 5, wherein one of the blade grids near the inner side of the blade grid pair is directly fixed on the turbine unit hub or fixed on the turbine unit hub through a wheel disc, and the wheel disc is provided with a second steam through hole in a flow area corresponding to each steam channel.
7. 7. The full-load efficient turbine unit of claim 6, wherein a fit gap exists between the annular moving-blade-grid isolation belt and the annular static-blade-grid isolation belt or the end of the partition wall, and a radial steam seal assembly is arranged in the fit gap.
8. 8. A full load high efficiency turbine assembly in accordance with claim 2 wherein the steam flow capacity of said steam path decreases from the outside to the inside.
9. 9. A full load high efficiency turbine assembly according to any one of claims 1 to 8, wherein at least one of said steam channels is provided by full circumferential steam.
10. 10. The full-load efficient thermodynamic system is characterized by comprising a boiler and the full-load efficient steam turbine unit according to any one of claims 1 to 9, wherein the acting cylinder body is a high-pressure cylinder, the boiler is connected with the steam channels one by one through a pipeline system, a main steam valve for controlling the on-off of the main steam flow of the boiler is arranged on the pipeline system, and at least one regulating valve is arranged between the main steam valve and each steam channel.
11. 11. The full-load efficient thermodynamic system of claim 10, wherein the pipeline system comprises a main steam pipeline and at least one stage of branch steam pipeline network, the main steam valve is arranged on the main steam pipeline, the branch steam pipeline network is composed of a plurality of branch steam pipelines, and the branch steam pipeline is provided with an adjusting valve.
12. 12. The full load high efficiency thermodynamic system of claim 11, further comprising a regenerator system comprising an adjustable heater, wherein the conditioning stage is coupled to the adjustable heater via a bleed line, wherein the bleed line is provided with a conditioning valve assembly, and wherein the adjustable heater is coupled to the boiler.
13. 13. A method of operating a full load efficient thermodynamic system as claimed in any one of claims 10 to 12, comprising the steps of: Sequencing from large to small according to the steam flow capacity of each steam channel, and sequentially determining a first steam channel and a second steam channel; dividing the operation load of the thermodynamic system into m load sections, and respectively corresponding each load section to one or more steam channels; And determining a target load interval which the thermodynamic system needs to enter according to the current running load rate of the thermodynamic system or according to the set target load rate, and switching to a steam channel corresponding to the target load interval.
14. 14. A method of operating a full load, high efficiency thermodynamic system as claimed in claim 13, When the thermodynamic system is in load lifting, determining a final steam channel to be switched to according to the load lifting rate or the target load rate requirement; directly opening a final steam channel, or; If other intermediate steam channels exist between the final steam channel and the current steam channel, starting the intermediate steam channels from the current steam channel in sequence or simultaneously starting the intermediate steam channels until the final steam channel is started; judging whether the current load reaches a set value, if so, gradually closing other steam channels except the final steam channel.
15. 15. A method of operating a full load, high efficiency thermodynamic system as claimed in claim 14, When the thermodynamic system is in load reduction, determining a final steam channel to be switched to according to the load reduction rate requirement; Gradually closing the regulating valve corresponding to the current steam channel; Judging whether the current load reaches a set value, if so, gradually opening the regulating valve corresponding to the final steam channel, and closing the regulating valve corresponding to the current steam channel.
16. 16. A method of operating a full load high efficiency thermodynamic system as claimed in any one of claims 13 to 15, wherein when the thermodynamic system has a load factor below a set rated load, the tuning valve assembly is opened and steam in the tuning stage is fed into the tunable heater.
17. 17. A method of operating a full load, high efficiency thermodynamic system as claimed in any one of claims 13 to 15, wherein the boiler stack temperature is sensed, and if the boiler stack temperature is below a set temperature value, the damper assembly is opened and the boiler stack temperature is adjusted to be above the set temperature value by controlling the opening of the damper assembly.

Description

Full-load efficient turbine unit, thermodynamic system and operation method Technical Field The invention belongs to the technical field of thermodynamic cycle, and particularly relates to a full-load efficient turbine unit, a thermodynamic system and an operation method. Background With the large-scale grid connection of new energy power such as photovoltaic power, wind power and the like with random fluctuation, the basic power taking coal-fired thermal power as a main body is forced to comprehensively participate in deep peak shaving. The coal-fired thermal power generating unit is mainly designed by considering the operation efficiency under the rated load working condition, the unit power generation efficiency under the medium-low load working condition in the deep peak shaving process is rapidly deteriorated, and compared with the rated load working condition, the coal consumption of the conventional coal-fired thermal power generating unit under the 30% rated load working condition is increased by 30-40 g/kW.h, so that the comprehensive energy saving and emission reduction benefits of the whole society generated for new energy yielding are greatly reduced. Based on the technology and structural characteristics of the existing steam turbine and thermodynamic system, under the low-load working condition, the main steam pressure is greatly reduced no matter in a sliding pressure operation mode, a constant pressure operation mode or a 'constant-sliding-constant' operation mode after the stage is regulated under the medium-low load. Under the medium-low load working condition, the great ideal enthalpy drop formed between the rated main steam pressure which can be provided by the boiler and the pressure after the regulating stage cannot be effectively utilized in the prior art, so that the circulation efficiency of the thermodynamic system is greatly reduced under the medium-low load working condition, and the energy consumption of the system is greatly increased. The system solves the problem of operation efficiency reduction under low-load working conditions in the deep peak shaving process of the coal-fired thermal power generating unit, is a key for energy conservation and consumption reduction, global energy conservation and emission reduction of enterprises and even for the on-schedule high-quality completion of national 'double-carbon' targets, and therefore, a steam turbine unit and a thermodynamic system which can still maintain higher cycle efficiency under medium-low-load working conditions are needed to solve the current problems. Disclosure of Invention In order to overcome the defects of the prior art, the invention aims to provide a full-load efficient steam turbine unit, a thermodynamic system and an operation method, which are mainly used for solving the problems of low operation efficiency, poor adjustment capability and the like of a coal-fired thermal power unit under medium and low loads in the deep peak regulation process in the prior art. In order to solve the problems, the technical scheme adopted by the invention is as follows: In a first aspect, the invention provides a full-load efficient steam turbine unit, which comprises a working cylinder body, wherein the working cylinder body is any one of a high-pressure cylinder, a medium-pressure cylinder and a low-pressure cylinder, a regulating stage is arranged in the working cylinder body, at least two steam channels are radially arranged in the regulating stage, the front ends of the steam channels are connected with at least one regulating valve for controlling the on-off of steam flow, at least one pressure stage is arranged in at least one steam channel, and each pressure stage consists of a static blade grid positioned at the front end and a movable blade grid positioned at the rear end. Further, there is at least one steam channel in which no static blade cascade or static blade cascade with constant axial flow area is arranged, and at the same time no moving blade cascade or moving blade cascade without reaction degree is arranged. Further, at least one pair of static blade grids in adjacent steam channels are connected in the radial direction, the static blade grids which are defined as a static blade grid pair in radial connection form an annular static blade grid isolation belt extending along the circumferential direction at the connection position, and the annular static blade grid isolation belt is connected to the tail end of a separation wall of the adjacent steam channels. Further, the stationary blade grating extends to the innermost steam channel directly or through a partition plate, and the partition plate is provided with a first steam through hole in a circulation area corresponding to each steam channel. Further, at least one pair of movable blade grids in adjacent steam channels are connected in the radial direction, the movable blade grids which define the radial connection are a movable blade grid pair, and