JPH0356723Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention relates to the warming of steam lines and equipment installed in the lines in power plants, and in particular to the recovery of warming steam to the same system as the steam source. The present invention relates to a warming device suitable for.

[Background of the idea]

FIG. 1 shows a system diagram of a power plant having a warming device in a turbine bypass line according to the prior art. In this figure, the forms of power generation are as follows. Steam from the steam generator 1 is transferred to the main steam pipe 2,
It passes through a regulating valve 3 and does work in a high pressure turbine 4.
Steam leaving the high-pressure turbine 4 passes through a low-temperature reheat steam line 7, a reheater 8, a high-temperature reheat steam line 9, and a control valve 10, performs work in a medium/low pressure turbine 11, and is discharged to a condenser 15. be done. Therefore, the power generated by rotating the turbine as the steam passes through the turbine is mechanically transmitted to the generator 12 to generate electric power.

On the other hand, since the high-pressure turbine bypass valve 5 and the low-pressure turbine bypass valve 14 are used during transient operations such as rapid load changes, both valves are closed and on standby during normal operation. If the turbine bypass device were to wait without warming during normal operation, high-temperature steam would suddenly flow into the turbine bypass device due to the opening operations of the high-pressure turbine bypass valve 5 and the low-pressure turbine bypass valve 14 due to load changes. Very high thermal stresses are created, creating problems that can even lead to failure of the turbine bypass valve.

For this reason, conventional high pressure turbine bypass line 6
A warming device consisting of a warming line 16 and an orifice 17 that bypasses the high-pressure turbine bypass valve 5 is installed in the low-pressure turbine bypass line 13, and a warming line 19 that bypasses the low-pressure turbine bypass valve 14 is installed in the low-pressure turbine bypass line 13.
A warming device consisting of an orifice 18 and an orifice 18 are installed, and during normal operation, steam is passed through both warming devices to heat the turbine bypass device and perform warming. In this case, the warming steam bypasses the turbine bypass valve and is discharged to the downstream high-pressure turbine bypass line 6 or the condenser 15, so the energy of the warming steam is not returned to the work of the turbine and is considerably This resulted in a heat loss of 50%.
Furthermore, since the warming device itself discharges high-temperature steam directly to the downstream system, countermeasures against deformation and erosion caused by thermal stress at the discharge section were required.

[Purpose of invention]

The purpose of this invention is to recover heat loss by utilizing pressure loss in the same system that is the steam source of warming steam, instead of making the warming steam do any work. An object of the present invention is to provide a warming device that can significantly reduce the amount of energy used.

[Summary of the idea]

Improving the thermal efficiency of power plants involves not only improving the performance of each device, but also reducing heat loss in the system. In current power generation plants, equipment installed in the steam line or its steam pipes, which are used for transient operations such as load changes and are on standby during normal operation, are warmed up by warming steam and are on standby. . In this case, since the warming steam is directly discharged from the high pressure region to the low pressure region, the use of this warming steam poses a problem in terms of thermal efficiency.

This invention aims to significantly reduce heat loss by utilizing the pressure loss that occurs in the main pipe, which is the source of the warming steam used during normal operation, and recovering the warming steam into the same system. be.
This can contribute to improving thermal efficiency by combining warming steam with the steam sent to the turbine during normal operation and reducing the warming steam to work.

[Example of idea]

FIG. 2 shows a system diagram in which a warming device is provided in a high-pressure turbine bypass line, which is an embodiment of the present invention. In this figure, the form of power generation is the same as the conventional technology, but the difference is that the high pressure turbine bypass line 6 upstream of the high pressure turbine bypass valve 5
A warming line 16 is installed from the high-pressure turbine bypass line 6 to the main steam line 2, and a warming line 17 is installed from the high-pressure turbine bypass line 6 downstream of the high-pressure turbine bypass valve 5 to the low-temperature reheat steam line 7. However, both warming lines 16,1
Even if a resistor such as an orifice is installed in 7, the original function of warming will not change.

By installing this warming device, the warming method will be as follows. During normal operation, the high pressure turbine bypass valve 5 is in a closed state, so steam from the main steam line 2 is transferred to the high pressure turbine bypass line 6.
It then passes through the warming line 16, is recovered to the main steam line 2, and is sent to the high pressure turbine. By using the pressure loss that occurs in the main steam line 2 from the branch point with the high-pressure turbine bypass line on the main steam line 2 to the confluence point of the warming line 16 and the main steam line 2, steam is supplied to the warming line 16. This is due to the flow of water. In addition, if steam is flowing in the warming line 16, warming is performed in the high pressure turbine bypass line 6 on the upstream side of the high pressure turbine bypass valve 5.
Since the steam can be heated, warming is possible even if the flow of steam shown in the figure is reversed due to the relationship between the pressure loss occurring in the main steam line 2 and the warming line 16. In particular, the closer the main warming line 16 is taken out from the high-pressure turbine bypass valve, the more effective the warming of the high-pressure turbine bypass valve 5 is.

On the other hand, the method for warming the high-pressure turbine bypass line 6 on the downstream side of the high-pressure turbine bypass valve 5 is similar to the warming method for the high-pressure turbine bypass line 6 on the upstream side of the high-pressure turbine bypass valve 5 described above.

By providing such a warming installation,
Warming steam from the main steam line 2 is recovered to the main steam line 2 again and sent to the high-pressure turbine 4, so the warming steam that was conventionally discharged to other systems is reduced to work in the present invention. It is possible to significantly reduce heat loss.

Further, in the warming device, the process from taking out steam to discharging steam is carried out in the same system, so problems of deformation and erosion caused by thermal stress are also eliminated.

FIG. 3 shows a system diagram in which a warming device is provided in the low-pressure turbine bypass line, which is an embodiment of the present invention. The form of power generation is the same as the conventional technology, but the difference is that a warming line 18 is installed from the low pressure turbine bypass line 13 upstream of the low pressure turbine bypass valve 14 to the high temperature reheat steam line 9. However, warming line 18
Even if a resistor such as an orifice is installed, the original warming function will not change.

By installing this warming device, the warming method and its effects become similar to those explained in FIG. 3. In addition, in the conventional technology, since the warming steam was discharged to the condenser 15, the main steam could not be reduced to work at all, and the warming steam in the high-pressure turbine bypass line was
Compared to what can be contributed to the medium and low pressure turbine side, the effect increases in terms of effective use of warming steam.

FIG. 4 shows a system diagram that is an application example combining FIGS. 2 and 3, which are an embodiment of the present invention.
This figure adds the effects of the embodiments of FIGS. 2 and 3, and the thermal efficiency is improved even more than that of FIGS. 2 and 3.

[Effect of idea]

According to the present invention, by recovering warming steam into the same system, it is possible to significantly reduce heat loss caused by conventionally discharging to other systems such as piping and a steam recovery container, contributing to improved thermal efficiency. Furthermore, since warming is performed within the same system, it is possible to eliminate the problem of thermal stress in the discharge section due to the difference in steam conditions between the extraction and discharge destinations of the warming steam.

[Brief explanation of the drawing]

Fig. 1 is a system diagram of a power generation plant with a warming device in the turbine bypass line according to the prior art, Fig. 2 is a system diagram of an embodiment of the present invention, and Fig.
The figure is a system diagram of another embodiment of the present invention, and Figure 4 is the second embodiment.
FIG. 3 is a system diagram of an application example of the present invention, which is a combination of FIGS. 1...Steam generator, 2...Main steam line, 4...
... High pressure turbine, 5 ... High pressure turbine bypass valve, 8 ... Reheater, 11 ... Medium/low pressure turbine,
12... Generator, 15... Condenser.

Claims (1)

[Claims for Utility Model Registration] A steam turbine, a steam supply path that supplies steam to the steam turbine, a steam exhaust path that discharges steam that has done work in the steam turbine, and a steam supply path that bypasses the steam turbine. In a power generation plant having a bypass path that connects a steam exhaust path via a valve, a first warming line that is directly connected between a portion of the bypass path upstream of the valve and the steam supply path is provided. A warming device for a power generation plant, further comprising: a second warming line directly connected between a portion of the bypass passage downstream of the valve and the steam exhaust passage.