JPS61212606A - Idling equipment of low-pressure turbine vane wheel - Google Patents

Abstract

PURPOSE:To realize the idle operation even if an extraction line for cooling steam does not exist by allowing cooling steam to circulation-flow in a low-pressure turbine vane wheel, controlling the internal pressure of a low-pressure wheel chamber, outlet temperature of a high-pressure wheel chamber or flow rate to each constant value. CONSTITUTION:Switching from the normal operation to idle operation of a low-pressure turbine vane wheel is carried-out by setting an intermediate-pressure steam reducing valve 9 and a stop valve 13 into closed state and other valves into closed state and operating them by the instruction supplied from an instruction board 15. Cooling steam is sent reversely into the low-pressure wheel chamber of a low-pressure turbine 2 from either a cooling steam 23 (a) system or an intermediate pressure steam 22 (b) system. Said cooling steam flows into the high-pressure wheel chamber side and inhaled by a cooling-steam circulation fan 11, cooled by a steam cooler 19, and then discharged into a low-pressure steam pipe 6, and thus circulation flow is realized. In this case, the inner pressure of the low-pressure wheel chamber, outlet temperature of the high-pressure wheel chamber, or the flow rate can be controlled to each constant value by a pressure control valve 16 or 16' and a temperature or flow-rate control valve 17.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to idling equipment for low-pressure turbine wheels, particularly in bleed back pressure turbines, bleed condensate turbines, and the like.

BACKGROUND OF THE INVENTION In a turbine system consisting of a high-pressure turbine and a low-pressure turbine in which the turbine wheel rotates a generator to obtain effective power, it may be necessary to idle one of the turbines. When the low-pressure turbine wheel is idling, some conventional methods flow cooling steam from the high-pressure section to the low-pressure section; In addition to the high temperature and therefore the need for a relatively large amount of steam, there is a disadvantage that the idling steam temperature in the low-pressure casing further increases because the outlet steam of the high-pressure turbine is used for the cooling steam. When there is no low pressure steam line for discharging steam, there is a problem in that the blade wheel cannot be idled.

Problems to be Solved by the Invention The object of the present invention is to realize idle operation of a low-pressure turbine wheel without a cooling steam discharge line.

Means for Solving the Problems The present invention introduces exhaust steam from a high-pressure turbine or low-pressure steam from another line into the low-pressure casing of a low-pressure turbine wheel to be idled through a pressure control valve. The steam discharged from the high-pressure casing is re-circulated into the low-pressure casing through a steam cooler, a cooling steam circulation fan, and a temperature or flow rate control valve, or the direction of circulation is reversed and the steam is circulated. At this time, the detected pressure value of the sent and exhausted steam is received to centrally control the pressure control valve, and the detected temperature or flow rate value of the sent and exhausted steam is received to centrally control the temperature or flow rate control valve, respectively, and the control valves are controlled centrally. Switching to operation and returning to operation are also centrally controlled.

Therefore, according to the structure of the present invention, cooling can be performed while controlling the internal pressure of the low-pressure casing to a constant level using the pressure control valve, and while controlling the outlet temperature or flow rate of the high-pressure casing to a constant level using the temperature or flow rate control valve. The steam circulates in the idling low-pressure turbine blade car, and idling operation can be performed without an exhaust line for the cooling steam, and the various controls described above and switching from normal operation to idling operation and return operation are automatically performed. Centralized control can be performed.

Embodiment Next, an embodiment of the present invention will be described with reference to the drawings. The high pressure The turbine has a main stop valve 7.
A high-pressure steam regulating valve 8 is interposed to connect the high-pressure steam pipe 4 to the high-pressure casing of the turbine to send high-pressure steam 21, and to connect the intermediate-pressure steam pipe 5 to the low-pressure casing of the turbine. an intermediate-pressure steam control valve 9 that is open during normal operation and closed during idle operation; A low pressure steam pipe is connected to the low pressure casing of the turbine, and a stop valve 13 that is open during normal operation and closed during idle operation is installed at the end of the pipe. A cooling steam inlet pipe 24 to which cooling steam 23 of the cooling steam command unit 4 is connected.
is connected to the low-pressure steam pipe through a cooling steam pressure control valve 16, or the low-pressure steam pipe and the medium-pressure steam pipe are connected to other cooling steam through an intermediate-pressure steam pressure control valve 16'. The former cooling steam inlet pipe 24 is connected by an inlet pipe 24/
The system (a) is used when cooling steam is introduced from the outside, and the latter system (b) of the other cooling steam inlet pipe 24' is used when high pressure turbine exhaust C (intermediate pressure steam) is introduced. In addition, the cooling steam circulation section (
Bl is a steam cooler 19 connecting the high-pressure casing of the low-pressure turbine and the low-pressure steam pipe through a cooling steam pipe 12 and sending and discharging cooling water 18 from the high-pressure casing side into the pipe; The pressure, temperature, flow rate, alarm and trip command panel 15 of the cooling steam command unit TCI is equipped with a circulation 7 ann 11 and a temperature or flow rate control valve 17, and a pressure detection unit attached to the low pressure steam pipe. 2
Upon receiving a detected pressure value of 0, the pressure control valve 16.16'
or control the temperature or flow rate control valve by receiving the detected temperature or flow rate value of the temperature or flow rate detection unit 14 attached to the high pressure casing side of the low pressure turbine of the cooling steam piping; Furthermore, high pressure steam control valve 8
, the intermediate pressure steam control valve 9, and the stop valve 13, respectively.

Therefore, during normal operation, the high-pressure steam control valve 8, intermediate-pressure steam control valve 9, and stop valve 13 are opened, and the temperature or flow rate control valve 17 and pressure control valve 16 or 16' are closed, respectively. When the low-pressure turbine wheel is running idle, the intermediate-pressure steam control valve and stop valve are closed, and the high-pressure steam control valve, temperature or flow rate control valve, and pressure control valve are opened, respectively, by a command from the command board 15. After activating and switching to idling operation, if cooling steam is reversely fed into the low pressure casing of the low pressure turbine 2 from either the cooling steam 23 bi) system or the intermediate pressure steam 22 (guchi) system, The cooling steam flows to the high pressure casing side and passes through the steam cooler 1.
While being cooled by 9Vc, the steam is sucked into the cooling steam circulation fan 11 and then discharged into the low pressure steam pipe 6 for circulation. Control valve 16 or 16/
is controlled to keep the internal pressure in the low-pressure turbine casing constant. However, the leakage from the turbine gland etc. is replenished via the pressure control valve, so constant pressure is maintained reliably, and the internal pressure is not higher than atmospheric pressure or back. The circulating cooling steam is set to a specified pressure lower than the temperature or flow rate detection unit 1.
The command panel that receives the detected temperature or flow rate value in step 4 controls the temperature or flow rate control valve 17 to maintain the temperature, etc. inside the nuclear vehicle compartment at the set value, so there is no problem with long-term idling operation. The command panel can switch to idling operation and normally perform idling operation by performing self-cooling without relying on a special cooling steam source or other steam lines for exhausting cooling steam.

In the above-mentioned embodiment, the flow direction of the cooling steam was described as a reverse flow direction from the low-pressure casing to the high-pressure casing, but since this is a self-cooling method, the normal flow direction from the high-pressure casing to the low-pressure casing is In this case, the cooler should be capable of cooling to a normal back air temperature and a temperature slightly higher than the saturation temperature of the cooling steam pressure, and if it is below the above temperature, drainage will occur, which is not preferable.

Effects of the Invention As described above, the present invention enables stable idling operation of the low-pressure turbine wheel even without a cooling steam discharge line, and also enables so-called top turbine operation.
Therefore, when there is a condensate turbine in the medium pressure line, it is possible to diversify the operation method such as extracting condensate operation, so it can be used as an energy-saving guitar bin, and the cabin pressure during idle operation is lower than the regular exhaust pressure. The idling loss can be significantly reduced because the pressure is low, just slightly higher than atmospheric pressure, and furthermore, in order to return to normal operation, the high-pressure turbine exhaust gas flows into the idling wheel chamber to increase the internal pressure. It is possible to migrate without stopping the turbine, etc.
The industrial utility value of this invention is extremely high.

[Brief explanation of the drawing]

The drawing is a system diagram showing an embodiment of the present invention. 1...High pressure turbine, 2...Low pressure turbine, 4...High pressure steam pipe, 5...Intermediate pressure steam pipe, 6...Low pressure steam pipe, 9...
Medium pressure steam control valve, 11. Cooling steam circulation fan, 12.
- Cooling steam piping, 13...Stop valve, 14...Temperature or flow rate detection section, 15...Command panel, 16.16'...Cooling steam pressure control valve, 17...Temperature or flow rate control valve, 19
...Steam cooler, 20..Pressure detection section, 21..High pressure steam, 22..Intermediate pressure steam, 23..Cooling steam, 24.24
'...(1 other person

Claims (1)

[Claims] Exhaust steam from the high-pressure turbine or low-pressure steam in another line is fed into the low-pressure casing of the low-pressure turbine wheel to be idled through a pressure control valve, and the steam discharged from the high-pressure casing of the blade wheel is converted into steam. The steam is re-introduced and circulated into the low-pressure casing through a cooler, a cooling steam circulation fan, and a temperature or flow rate control valve, or the direction of circulation is reversed, and at that time, the detected pressure value of the sent and discharged steam is received. receiving the detected temperature or flow rate value of the sent and exhausted steam to centrally control the temperature or flow control valve, respectively, and also centrally control the switching from normal operation to idle operation and the return operation. A low-pressure turbine wheel idling equipment characterized by: