JP2000027749A - Ground steam discharging system for geothermal condensing turbine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve a ground steam discharging system so as to discharge the ground steam without generating a trouble while utilizing a main steam condensing and gas extracting system, and to lower the cost while saving a dedicated auxiliary machine related to the discharge of the ground steam. SOLUTION: A steam condenser 3 and gas extractors 4, 5 for extracting the non-condensing gas from the steam condenser 3 are combined in a rear stage of a geothermal condensing turbine. In this turbine, a ground steam discharging line 7 drawn from a ground packing part 2 of the turbine 1 is connected to a suction side of the gas extractor 4, which is connected to the steam condenser 3, through a pressure adjusting throttle 10, and the ground leaked steam and the air sucked from an axial end are discharged into the atmospheric air with the non-condensing gas extracted from the steam condenser 3.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a ground steam discharge system for a turbine for a geothermal power generation turbine.

[0002]

2. Description of the Related Art As is well known, a gland packing (labyrinth packing) is provided in a steam turbine in order to prevent steam leakage from a portion where a rotor shaft penetrates a casing and air from entering a casing from a shaft end. Gland steam is caused to flow through the gland packing to seal the shaft. Here, FIG. 4 shows a conventional ground steam discharge system employed in a geothermal condensing turbine plant.

In FIG. 4, 1 is a turbine, 2 is a gland packing part (labyrinth packing), 3 is a condenser for exhaust steam in combination with the latter stage of the turbine 1, and 4 and 5 are contained in geothermal steam. First and second stage gas extractors (ejectors) 4a and 5a for extracting non-condensable gas from the condenser 3 and discharging the gas to the outside of the system (into the atmosphere). Reference numeral 6 denotes a gland steam supply line for supplying steam for sealing to the gland packing portion 2 from outside via a gland steam header or the like, and 7 denotes gland leaking steam drawn from the negative pressure pocket of the gland packing portion 2 and from the shaft end. A ground steam exhaust line for extracting the sucked air, 8 is a ground steam condenser connected to the ground steam exhaust line 7, and 9 is a blower. The condensate recovered by the condenser 3 is used as cooling water for the condenser 3 after being cooled by a cooling tower or the like. In some plants, the ground steam condenser 8 is omitted, and the ground steam is directly discharged to the outside of the system using only the exhaust fan 9.

[0004]

As described above, in the conventional gland steam system, in order to discharge the gland leaking steam from the gland packing portion 2 and the air sucked in from the shaft end, the main steam condenser 3, Since a dedicated ground steam condenser 8 and a ventilator 9 are provided separately from the gas extractors 4 and 5, the number of auxiliary machines in the turbine plant increases, and the equipment cost and maintenance management cost also increase accordingly.

[0005] In a relatively small-scale turbine plant such as geothermal power generation, it is demanded that the auxiliary equipment be simplified as much as possible to improve the cost performance in terms of facility costs and maintenance costs. On the other hand, geothermal steam contains a large amount of gas components in the steam, unlike steam generated in a boiler of a typical thermal turbine plant. For this purpose, gas extractors 4 and 5 connected to the condenser 3 of the geothermal turbine use gas extractors having a large exhaust capacity. When an actual turbine plant is constructed, the exhaust capacity is large in terms of specifications. A gas extractor with some extra room is used.

On the other hand, the amount of exhaust of the ground steam is very small compared to the amount of gas extracted from the above-mentioned main steam. It has been confirmed that even when the amount of gas to be discharged from the vessel and the amount of exhaust of the ground steam are combined, the exhaust capacity of the gas extractor attached to the condenser exceeds this. In addition, the geothermal turbine eliminates the need to recover heat from ground steam and condensate.

Accordingly, the present invention is based on the results of the above verification, and is improved so that ground steam can be discharged without hindrance using a condensate system for main steam and a gas extraction system. It is an object of the present invention to provide a ground steam exhaust system for a geothermal condensate turbine, which reduces the cost by omitting the above.

[0008]

SUMMARY OF THE INVENTION According to the present invention, there is provided a geothermal condensate comprising a turbine, a condenser, and a gas extractor for extracting non-condensable gas from the condenser and discharging the gas to the outside of the system. This is achieved by configuring the gland steam exhaust system in the turbine as follows. (1) Connect the gland steam exhaust line drawn from the gland packing part of the turbine to the suction side of the gas extractor connected to the main steam condenser to condense the gland leaking steam and the air sucked from the shaft end. It is configured to be discharged through the gas extractor together with the non-condensable gas extracted from the device (claim 1).

(2) The gland steam discharge line drawn from the gland packing part of the turbine is connected to the main steam condenser, and the gland leaking steam and the air sucked in from the shaft end are extracted from the condenser by non-condensation. It is configured to be discharged through a gas extractor together with the neutral gas (claim 2). (3) In paragraphs (1) and (2) above, connect a throttling means for pressure adjustment to the gland steam discharge line, and adjust the gland steam pressure so that the gland steam maintains an appropriate shaft sealing pressure in the gland packing. (Claim 3).

[0010] According to the above-described configuration, an auxiliary device such as a dedicated ground steam condenser and a blower is not required for the ground steam discharge system, so that the cost of equipment and maintenance can be reduced accordingly.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to the embodiments shown in FIGS. In each embodiment, the same reference numerals are given to devices corresponding to FIG. [Embodiment 1] FIG. 1 shows an embodiment corresponding to claims 1 and 3 of the present invention. In this embodiment, a gland steam discharge line 7 drawn from a gland packing portion 2 of a turbine 1 is provided with a throttle (orifice) 1 for pressure adjustment.
0 is connected to the suction side of the first stage gas extractor (ejector) 4 connected to the condenser 3.

With this configuration, the ground leaking steam discharged from the gland packing portion 2 through the gland steam discharging line 7 during the operation of the turbine 1 and the air sucked in from the shaft end form the non-condensable gas extracted from the condenser 3. Together with the gas in the first stage gas extractor 4, and is discharged out of the system (atmosphere) through the second stage gas extractor 5 in the subsequent stage. In this case, the gas extractors 4 and 5 have a large exhaust capacity corresponding to the large amount of gas contained in the geothermal steam as described above. The ground vapor from the gland packing portion 2 can be discharged to the atmosphere together with the non-condensable gas without substantially affecting the function of extracting the non-condensable gas. In addition, the throttle 1
By inserting 0, the ground steam discharge line 7 can be maintained at an appropriate pressure slightly lower than the atmospheric pressure without being affected by a high degree of vacuum on the suction side of the gas extractor 4.

[Embodiment 2] FIG. 2 shows an applied embodiment of the first embodiment. In this embodiment, a ground steam discharge line 7 is cascade-connected to a stage following the first stage gas extractor 4. The gland leakage steam and air collected from the gland packing part 2 are connected to the suction side of the stage gas extractor 5 and are discharged to the atmosphere through the second stage gas extractor 5. In this embodiment, the ground steam discharge line 7 is also used.
The pressure of the ground steam is adjusted by interposing a throttle 10 at the bottom.

FIG. 3 shows a third embodiment of the present invention.
3 shows an embodiment corresponding to FIG. In this embodiment, a ground steam discharge line 7 is connected to a condenser 3 for condensing main steam of the turbine 1 via a throttle 10. In such a configuration, the ground leakage steam discharged from the gland packing portion 2 through the gland steam discharge line 7 and the air sucked in from the shaft end are once discharged to the condenser 3 and then discharged from the condenser 3 in the geothermal steam. The non-condensable gas is released to the atmosphere via gas extractors 4 and 5.

[0015]

As described above, according to the structure of the present invention, it is possible to omit the auxiliary equipment such as the ground steam condenser and the exhaust fan dedicated to the ground steam used in the conventional ground steam system. And cost reduction in plant equipment and maintenance management can be achieved.

[Brief description of the drawings]

FIG. 1 is a system diagram of a ground steam discharge system according to a first embodiment of the present invention.

FIG. 2 is a system diagram of a gland steam discharge system according to a second embodiment of the present invention.

FIG. 3 is a system diagram of a ground steam discharge system according to a second embodiment of the present invention.

FIG. 4 is a diagram of a conventional ground steam discharge system of a geothermal condensing turbine.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Turbine 2 Gland packing part 3 Condenser 4 1st stage gas extractor 5 2nd stage gas extractor 7 Gland steam discharge line 10 Throttle

Claims (3)

[Claims] 1. A geothermal condensing turbine in which a condenser and a gas extractor for extracting non-condensable gas from the condenser and discharging the gas to the outside of the system are provided at a stage subsequent to the turbine, and are drawn out from a gland packing part of the turbine. Connected to the suction side of the gas extractor connected to the condenser, and the gland leakage steam and air sucked from the shaft end are discharged together with the non-condensable gas extracted from the condenser. A ground steam discharge system for a geothermal condensate turbine, wherein the ground steam is discharged through an extractor. 2. A geothermal condensate turbine in which a condenser and a gas extractor for extracting non-condensable gas from the condenser and discharging the gas to the outside of the system are provided at a stage subsequent to the turbine. Connected to the condenser so as to discharge the ground leakage steam and the air sucked from the shaft end together with the non-condensable gas extracted from the condenser through the gas extractor. A ground steam discharge system for a geothermal condensing turbine. 3. The ground steam condensing system according to claim 1, wherein a throttle means for pressure adjustment is connected to the ground steam discharge line to adjust the ground steam pressure. Ground steam exhaust system for turbines.