JPS5977010A - Flushing system for geothermal turbine - Google Patents

Abstract

PURPOSE:To make it possible to effectively flush a turbine without disassemblying the turbine, by charging hot cleaning water into the turbine from the outside while a turbine rotor is rotated by a turning device to flush and scale a turbine wheel chamber. CONSTITUTION:Upon cleaning a turbine 1 the supply of main steam is cut off beforehand to stop operation of the turbine 1 for spontaneously cooling the inside of the turbine 1. Then, connection of a hot cleaning water supply line 10, a drainage discharge line 20 and a compressed air supply line 30 is at first made to the turbine 1, and as well hot water is charged into a condenser 2 to protect a bollows 9. Further, compressed air is fed to a gland packing 6 through the above-mentioned line 30. Next, after hot water being charged into a turbine wheel chamber 4 through the above-mentioned line 10, a turbine rotor 5 is rotated by means of a turning device 8. Therefore, water is stirred to flush the inside of the turbine wheel chamber 4 and the turbine rotor 5. Thereafter, effluent water after flushing is discharged through the abovementioned line 20.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for cleaning the inside of a casing of a geothermal turbine that operates using geothermal steam obtained from a steam well as a working fluid.

Geothermal steam, which is the working fluid of the geothermal turbine, is ejected from deep underground, and contains mud and other impurities as well as corrosive components dissolved in hot water. Most of this hot water is separated and removed by a steam separator before the turbine is introduced, but some still enters the turbine along with mud and other solids from the earth's crust. Also, impurities contained in the steam, primarily silica, cause scaling problems. In particular, scales on the surface of the blades narrow the steam passage area and cause a reduction in output. These problems are unique to geothermal turbines and are not found in ordinary thermal turbine plants.

This invention was made in response to the above problems.
The purpose of the present invention is to provide a new and unprecedented cleaning method capable of cleaning and discharging mud and corrosive components accumulated inside the cabin and removing scale without disassembling the turbine.

According to the present invention, the present invention is equipped with a cleaning hot water supply line and a drain drainage line that are connected to the turbine casing. , Inject cleaning hot water to a predetermined level into the turbine casing through the cleaning hot water supply line, and rotate the turbine rotor using a turning device to clean the inside of the casing and the turbine rotor and remove deposited scale. This is achieved by later discharging the cleaning waste liquid to the outside through the drain line.

The system of the present invention will be explained below based on the illustrated embodiments.

The figure shows a system diagram for implementing the cleaning method of the present invention. In the figure, 1 is a geothermal turbine, 2 is a condenser connected to the exhaust side of the geothermal turbine, and the main steam supply line 3 is connected to a steam well. The turbine 1 is operated by introducing geothermal steam from the turbine. Further, as is well known, the turbine 1 is made up of a casing 4, a turbine rotor 5, a gland packing 6 for shaft sealing, a drain pipe 7 pulled out from the casing 4 in each stage, and an axle shaft. A turning device 8 is connected to one end of the rotor. Further, the turbine casing 4 and the condenser 2 are connected to each other via a bellows 9. According to the present invention, such a turbine is provided with a cleaning hot water supply line 10 and a drain drainage line 20, and each line 10, 20 is connected to the turbine 1 during cleaning. Among these, the cleaning hot water supply line 10 includes a water tank 11 connected to a water supply source, a water supply heater 12, and a liquid supply pump 1.
3 and a hot water valve 14, and is connected to, for example, a flange of an internal inspection window of the passenger compartment 4;
0 is the drain pipe 7 and drain bit 2 on the passenger compartment side mentioned above.
1, and a drain valve 22 is inserted in the line. In addition, a branch hot water supply line 15 is drawn out from the middle of the complete hot water supply line 10, and a connector 2 attached to the tip of the drain drainage line 20 is connected to the tip of the branch hot water supply line 15.
3.

Note that 17 is a hot water supply valve inserted in the branch hot water supply line 15. In addition, a compressed air supply line 30 is connected to the gland packing 6 of the turbine 1 from a compressor 31 via an air supply valve 32.

Next, a method for cleaning the turbine 1 will be described. During periodic inspections or other necessary times, the dirt inside the turbine is visually observed using a borescope, etc., and if it is determined that cleaning is necessary, the turbine is cleaned according to the order of the missing items. . In other words, first, the supply of main steam is stopped and the rotation of the turbine 10 is stopped, and in order to ensure the safety of the subsequent work and to prevent the generation of thermal stress in the turbine, it is necessary to wait until the internal temperature of the turbine drops to about 1000℃ (4). Cool down naturally. Next, the completed cleaning hot water supply line 10. Drain drainage line 20. In addition to connecting the compressed air supply line 30, on the other hand, for the purpose of maintaining the bellows 9 on the condenser side, #1 is kept at the same temperature of 50υ during normal operation of the turbine in the body of the condenser. Fill with warm water. Note that the drain valve of the condenser 2 and the drain valves 22 of the drain drainage line 20 are all closed. Furthermore, compressed air is supplied under pressure to the compressed air supply line 30.1 gland packing 6. In this state, the hot water supply line 10 is then passed through the
Hot water heated to 0°C is injected into the vehicle compartment 4, and the hot water is stored in the interior of the vehicle compartment 4, indicated by H in the figure, to about half the height, and the turning device 8 is started. The turbine rotor 5 is driven to rotate. This agitates the cleaning hot water injected into the passenger compartment and removes mud and debris that have adhered to the interior of the passenger compartment and the turbine rotor.

Clean other corrosive components and remove scale. Note that since the gland packing 6 is pressurized with compressed air from the outside, hot water will not leak outward through the gland packing.

After performing this cleaning operation for a predetermined time, for example, about ω minutes,
Next, the drain valve 22 of the drain drain line 20 is opened, and the cleaning water in the vehicle interior is drained through the drain drain line 20 to the drain bit 21, and mud, dirt, scale, etc. are flowed out to the outside of the turbine. Further, the branch hot water supply line 15 and the drain drain line 20 are connected to each other via the connector 16.23, and the drain drain line 20 is connected through the branch line 15.
By supplying hot water in reverse, the piping of the drain pipe 7 and the drain drainage line 15 are cleaned and pipe clogging is prevented. The progress of the above cleaning operation was checked by visually inspecting the interior with a borescope through the flange of the inspection window that supplies hot water to the passenger compartment 4, and checking for any abnormalities and the degree of cleaning.)
Also, judge by looking at the repellency of cleaning water flowing out from the drain line. If it is judged that the cleaning has been done sufficiently, next time, with the hot water supply stopped, drain the drain line 2.
After completely draining the cleaning water from the passenger compartment through 0 and draining the inside of the condenser 2, each line 10
, 20 and 30 will be removed, and the blind covers will be restored where necessary to prepare for restarting turbine operation. In addition, the inside of the cabin of turbine 1 did not freeze when drain was removed.
Active drying is recommended to prevent rust. Furthermore, while rotating the turbine rotor by hand turning, the interior is visually inspected using a borescope to confirm that there are no abnormalities, and then the turbine operation using main steam is resumed.

According to the above-mentioned cleaning method of the present invention, cleaning hot water is injected from the outside and the turbine rotor is rotated using a turning device 7 while cleaning the interior of the vehicle and removing scale. The turbine can be effectively cleaned without disassembling the turbine, and its practical effects are extremely large.

[Brief explanation of drawings]

The figure is a cleaning system diagram showing an embodiment of the present invention. DESCRIPTION OF SYMBOLS 1... Turbine, 2... Condenser, 3... Main steam supply line, 4... Vehicle compartment, 5... Turbine rotor, 6...
・Grand packing/, 7... Drain pipe ゛, 8・
・Turning device, 10...Washing hot water supply line, 2
0...Drain drainage line, 30...Compressed air supply line.

Claims (1)

[Scope of Claims] 1) A geothermal turbine that operates using geothermal steam obtained from a steam well as a working fluid, which is equipped with a cleaning hot water supply line and a drain drainage line that are connected to the turbine casing, and which uses steam during cleaning. While the steam supply from the main steam line leading to the well is stopped and the turbine operation is stopped, wash hot water is injected into the turbine casing to a predetermined level through the wash hot water supply line, and the turbine rotor is turned by a turning device. A geothermal turbine cleaning method characterized in that the geothermal turbine is rotationally driven to clean the inside of the casing and the turbine rotor, remove deposited scale, and then discharge cleaning waste liquid to the outside through a drain discharge line. 2. In the cleaning method described in claim 1, external compressed air is supplied under pressure to the gland packing part of the turbine during cleaning to prevent leakage of hot water for cleaning from the gland packing part. This is a one-heat turbine cleaning method characterized by the following. 3) In the cleaning method described in claim 1, the interior of the condenser connected to the rear stage of the turbine is filled with hot water almost at a temperature during normal operation during cleaning, and when cleaning is completed, A geothermal turbine cleaning method characterized by draining water from inside the shell.