JP2766370B2 - Starting device for combined cycle power generation unit - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial application field) The present invention is configured by connecting a gas turbine, a steam turbine, and a generator coaxially, and is provided from another power generation unit or external equipment. The present invention relates to a starter for a combined cycle power generation unit having an auxiliary steam head capable of receiving a supply of auxiliary steam.

(Prior Art) Conventionally, in a so-called single-shaft combined cycle power generation unit in which a gas turbine, a steam turbine, and a generator are coaxially arranged, a starting device having a starting motor and a torque converter as starting means is generally provided. Was.

A typical single-shaft combined cycle power generation unit is configured as shown in FIG. In this power generation unit, one end of a shaft 1a of a generator 1 is coaxially connected to a shaft 2a of a gas turbine 2 and the other end thereof to a shaft 3a of a steam turbine 3 via a coupling or the like. The combined cycle power generation unit includes a starting motor 4 and a torque converter 5.
Is provided, and the starting device 6 and the shaft 2a of the gas turbine 2 are connected via an auxiliary gear 7.

Then, the starting motor 4 is rotated, and the torque is transmitted to the gas turbine 2 via the torque converter 5 and the auxiliary gear 7.
Of the combined cycle power generation unit.

When starting the combined cycle power generation unit, the power generation unit in which the gas turbine 2, the generator 1, and the steam turbine 3 are interconnected is shown by a solid line in FIG. 5 when the warming of the feed water heater (HRSG) is not required. When necessary, the rotation is increased according to the rotation increase curve shown by a part of the solid line and the broken line. Of the torque required for the rotation increase, the torque assigned to the starting device 6 is represented by a required torque curve indicated by a chain line in FIG.

Then, the start motor 4 is rotated by the start command, the torque converter 5 transmits the torque required for the rotation via the auxiliary gear 7, and then, for safety, the purge operation of the unburned fuel is performed. And, after the purge operation ends,
The ignition operation is performed at the gas turbine ignition speed, and the required torque provided by the starting motor 4 and the torque converter 5 is gradually replaced by the gas turbine combustion torque. It is designed to be capable of self-sustaining start-up only by itself.

The required torque curve shown by the dashed line in FIG.
Indicates that the required torque has completely shifted to the gas turbine combustion torque side.

The gas turbine exhaust gas after ignition of the gas turbine is used as a heat source for generating steam for the steam turbine in the exhaust heat recovery boiler.

The steam supply system to the steam turbine 3 is configured as shown in FIG.

This steam turbine plant uses a high-pressure superheater 9, a high-pressure main steam pipe stop valve 1
0, guided sequentially to the high-pressure main steam pipe 12 through the high-pressure main steam flow meter 11, and guided from the high-pressure main steam pipe 12 to the steam turbine 3 through the high-pressure steam valve 13.

The bypass pipe branched from the high-pressure main steam pipe 12 is provided with a high-pressure bypass stop valve 14, and one of the steam passing through the high-pressure bypass stop valve 14 is provided with a high-pressure bypass valve.
The steam is supplied to the gland portion of the steam turbine 3 through the cooling device 15 and the temperature reducing device 16 to seal the same, and other steam is supplied to the degassing steam valve 17, the degassing steam check valve 18, and the degassing steam stop valve 19. And it is led to the condenser 21 from the temperature reducing device 20.

On the other hand, the auxiliary steam header 22, which receives the supply of auxiliary steam from another combined cycle power generation unit or external equipment
The auxiliary steam header 22 is connected between the degassing steam check valve 18 and the degassing steam stop valve 19 via an auxiliary steam pipe 23, and the auxiliary steam header 22 Seki
In the pipe 23, a pipe provided with an auxiliary steam inflow valve 24 and a flow meter 25, and a pipe provided with an auxiliary steam supply check valve 26, a flow meter 27 and an auxiliary steam supply valve 28 are provided in parallel. The steam is introduced from the steam inflow system 29.

(Problems to be solved by the invention) Here, the combined cycle power generation equipment has high efficiency,
Since it has excellent operation characteristics such as rapid startup and low pollution, it is used for day-night power load adjustment or for weekend stop, and the start-stop operation is frequently performed.

Due to the start and stop, the starting motor and the torque converter are repeatedly forced to perform a high load operation. In particular, since the adjustment of the transmission torque is performed by the torque converter, the life of each component of the torque converter is drastically consumed, which causes a trouble, and if the torque converter causes a trouble, it becomes impossible to start the power generation unit. Would.

In addition, the starting motor capacity of the existing large gas turbine is about 1000 kW, and the ratio of power in the plant as a single accessory is high, and the capacity of the transformer for auxiliary devices in the plant is necessarily large. At present, there is a problem that it is done.

The present invention has been made in view of the above-described circumstances, and an object of the present invention is to provide a starting device for a combined cycle power generation unit that improves the reliability of starting the power generation unit and reduces the capacity of a transformer for in-house auxiliary equipment. Aim.

[Configuration of the invention]

(Means for Solving the Problems) In order to achieve the above object, a starting device for a combined cycle power generation facility according to the present invention connects a gas turbine, a steam turbine, and a generator coaxially, and attaches an auxiliary steam header. In the combined cycle power generation unit starting device, the auxiliary steam pipe extending from the auxiliary steam header and the high-pressure main steam pipe that guides the high-pressure main steam to the steam turbine are connected by an auxiliary steam bypass pipe, and the auxiliary steam bypass pipe is connected to the auxiliary steam pipe. A steam stop valve, an auxiliary steam control valve, and an auxiliary steam check valve are arranged, and the auxiliary steam control valve controls the steam flowing through the auxiliary steam pipe from the start of the power generation unit to the ignition of the gas turbine, and the steam turbine operates at a specified speed increase rate. The steam turbine is controlled to the amount of steam that can be rotated upward, and then the steam turbine The steam amount is controlled so that the torque generated by the steam on the gas side gradually replaces the combustion torque on the gas turbine side.

(Operation) The starting device of this combined cycle power generation unit
When the power generation unit is started, the steam supplied to the auxiliary steam header is guided from the auxiliary steam pipe and the auxiliary steam bypass pipe to the steam turbine, and the steam is used to rotate the steam turbine, and thus the generator and the gas turbine. The power generation unit can be started without having a starter having a torque converter or the like.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 shows a first embodiment of a starting device for a combined cycle power generation unit according to the present invention. The same members as those of the conventional combined cycle power generation unit are denoted by the same reference numerals, and description thereof will be omitted.

The difference between this combined cycle power generation unit and the conventional power generation unit is that the auxiliary steam pipe 23 and the high-pressure main steam pipe 12 are connected by an auxiliary steam bypass pipe 30 and the auxiliary steam bypass pipe 30 Is that an auxiliary steam stop valve 31, an auxiliary steam control valve 32, and an auxiliary steam check valve 33 are sequentially interposed. Further, a high-pressure main steam check valve is provided upstream of the connection between the high-pressure main steam pipe 12 and the auxiliary steam bypass pipe 30.
34 are interposed.

In the operation from the start of the power generation unit to the ignition of the gas turbine, steam is introduced from the external steam inflow system 29 to the auxiliary steam head 22 to perform warming of the auxiliary steam system. Steam inflow valve
The steam guided from the auxiliary steam pipe 24 to the auxiliary steam pipe 23 is introduced from the auxiliary steam bypass pipe 30 to the high-pressure main steam pipe 12, and the high-pressure steam valve 13 is opened to flow into the steam turbine 3 and rotate it. At this time, the auxiliary steam control valve 32
The steam flow is controlled so that the rotation speed can be increased at a specified rate of increase, and the seal steam is supplied to the gland of the steam turbine 3.

If you need to warm the feed water heater here,
In the operation from the gas turbine ignition rotation speed to the feed water heater warming rotation speed, the steam for generating the necessary torque on the steam turbine 3 side from the auxiliary steam header 22 via the auxiliary steam control valve 32 in the same manner as described above. And the supply of seal steam to the gland of the steam turbine 3.

Next, from the rotation speed equivalent to the warming of the feed water heater to the rated rotation speed, and for the operation after the rated rotation speed, the combustion torque on the gas turbine side and the torque by the steam on the steam turbine side are gradually switched, and the self-sustained startup is started by the combustion torque. It becomes possible.

Then, after the self-sustaining start rotation speed, the high-pressure steam valve 13 is fully closed, cooling steam for preventing overheating of the last stage blade of the steam turbine 3 is taken from the low-pressure steam valve 13a, and the operation shifts to the same operation as the normal start-up. It has been done.

FIG. 2 shows a rotation rise curve of the combined cycle power generation unit by a solid line or a broken line. In order to obtain a required torque curve corresponding to this rotation rise curve (see a dashed line in FIG. 5), the steam turbine 3 Is adjusted as shown by a dashed line.

With this configuration, the rotation increase of the power generation unit, which is conventionally performed by the starting motor, can be similarly performed by introducing auxiliary steam to the steam turbine.

FIG. 3 shows another embodiment, which is different from the above embodiment in that the auxiliary steam bypass pipe 30 is connected to the high pressure main steam pipe 12 on the upstream side of the high pressure steam valve 13 in the above embodiment. On the other hand, in the present embodiment, the auxiliary steam bypass pipe 30 is connected to the high-pressure steam valve 13.
Is connected to the high-pressure main steam pipe 12 on the downstream side of the steam turbine to guide auxiliary steam between the high-pressure steam valve 13 and the steam turbine 3.

〔The invention's effect〕

Since the starting device of the combined cycle power generation unit according to the present invention is configured as described above, the auxiliary steam bypass performs the same process as the rotation increase of the power generation unit conventionally performed via the starting device having the starting motor and the torque converter. The amount of auxiliary steam passing through the pipe is controlled by the auxiliary steam control valve according to the start-up stage of the power generation unit, and the controlled auxiliary steam is guided to the steam turbine. The rotation of the combined cycle power generation unit can be increased by controlling the amount of auxiliary steam guided to the steam turbine, eliminating the need for dynamic equipment such as a starter motor and torque converter. On the other hand, the starting device having the starting motor, which is an auxiliary machine having a large motor capacity, and a torque converter, which is likely to cause trouble due to frequent starting and stopping operations, is not required. There are effects such as being able to be greatly reduced.

[Brief description of the drawings]

FIG. 1 is a system diagram showing an embodiment of a starter of a combined cycle power generation unit according to the present invention, FIG. 2 is a graph showing a rotation speed rise curve and a required steam amount curve when starting by the starter, 3 is a system diagram showing another embodiment of the present invention, FIG. 4 is a schematic diagram showing a conventional combined cycle power generation unit, and FIG. 5 is a diagram showing a rotation rise curve and a required torque curve when starting up the conventional power generation unit. FIG. 6 is a system diagram of the steam turbine. 1 ... generator, 2 ... gas turbine, 3 ... steam turbine, 12 ... high-pressure main steam pipe, 13 ... high-pressure steam valve, 21 ... condenser, 22 ... auxiliary steam header, 23 ... Auxiliary steam pipe, 29…
... external steam inflow system, 30 ... auxiliary steam bypass pipe, 31 ...
Auxiliary steam stop valve, 32 ... Auxiliary steam control valve, 33 ... Auxiliary steam check valve, 34 ... High pressure main steam stop valve.

Claims (1)

(57) [Claims] A starting apparatus for a combined cycle power generation unit having a gas turbine, a steam turbine, and a generator coaxially connected and having an auxiliary steam header,
An auxiliary steam pipe extending from the auxiliary steam header and a high-pressure main steam pipe for guiding high-pressure main steam to the steam turbine are connected by an auxiliary steam bypass pipe, and an auxiliary steam stop valve, an auxiliary steam control valve, and an auxiliary steam are provided in the auxiliary steam bypass pipe. A check valve is disposed, and the auxiliary steam control valve controls the steam flowing through the auxiliary steam pipe from the power generation unit to the gas turbine ignition to a steam amount that allows the steam turbine to rotate and rise at a specified rate of increase,
Thereafter, the combined cycle power generation unit is characterized in that the amount of steam is controlled so that the torque by the steam on the steam turbine side is gradually replaced with the combustion torque on the gas turbine side until the self-sustained start by the combustion torque on the gas turbine side is possible. apparatus.