JPH08189311A - Electric power generating method by regenerative type gas turbine - Google Patents

Abstract

PURPOSE: To realize a regenerative type gas turbine electric power generating method improving electric power generating efficiency. CONSTITUTION: Electric power is generated by driving a gas turbine 9 by high temperature high pressure combustion gas, and steam is generated by an exhaust heat boiler 10 using combustion exhaust gas as its heating source in the case of using combustion exhaust gas as a source of heating compressed air to supply to a combustor 4 of the gas turbine 9 by way of introducing it to the exhaust heat recovery boiler 10 furnished with a heat exchanger. Thereafter, after mixing this steam with compressed air before heating, it is heated by the heat exchanger provided on the upstream side in the exhaust heat recovery boiler 10 and supplied to the combustor 4. Consequently, it is possible to remarkably improve electric power generating efficiency only by improving a part of a system of an electric power generating device by a regenerative type gas turbine.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power generation method using an improved regenerative gas turbine which has significantly improved power generation efficiency.
More specifically, the present invention relates to a power generation method using an improved regenerative gas turbine in which the heat energy of high-temperature and high-pressure combustion gas is effectively used to reduce the waste heat energy and significantly improve the power generation efficiency of the gas turbine.

[0002]

2. Description of the Related Art The main methods of converting energy from combustion into electric energy through a prime mover include a gas turbine power generation method and a steam turbine power generation method. When a gas turbine is used, the gas turbine is usually rotated by high-temperature high-pressure gas obtained by combustion of compressed air and fuel, and power is taken out from the rotating turbine shaft. On the other hand, when using a steam turbine, the turbine is rotated by the high-temperature and high-pressure steam generated in the boiler,
Power is taken from the rotating turbine shaft. Comparing the thermal efficiencies of the two, the thermal efficiency of the gas turbine exceeds that of the steam turbine.
Exhaust gas having a high temperature of 600 ° C. is discharged. Therefore, a gas turbine combined cycle power generation method that combines the advantages of both has been developed and put to practical use. That is, a plurality of 100,000 kW-class gas turbines are operated to efficiently generate electricity, and steam is generated using the exhaust heat of the resulting exhaust gas to generate electricity using a steam turbine, and the thermal energy of the combustion gas is generated twice. It is a method of collecting and generating electricity.

Recently, as an improved type of power generation by a gas turbine, the high temperature exhaust gas after driving the gas turbine and the compressed air supplied to the combustor of the gas turbine are heat-exchanged by a heat exchanger to heat the compressed air, Regenerative cycle power generation (power generation by a regenerative gas turbine) that reduces fuel in the gas turbine and consequently improves thermal efficiency (power generation efficiency) of the gas turbine has become known. In order to further improve the output of the gas turbine, JP-A-5-332164 discloses a cooling means such as spraying water into compressed air in order to recover the exhaust energy of the gas turbine to a low temperature level. The technology to provide is proposed.
Further, in Japanese Unexamined Patent Publication No. 6-212909, in a combined power generation plant in which exhaust gas of a gas turbine is injected into a boiler as combustion air, the exhaust gas heat of the boiler heats air or fuel injected into a combustor of the gas turbine. Technology is proposed.

[0004]

Although the gas turbine combined cycle power generation has a high thermal efficiency of 43 to 47% (HHV base, HHV: high heating value) as compared with the conventional power generation method, it is still sufficiently satisfactory. is not. In particular, in the current situation where the electrification rate, which shows a tendency to shift energy demand to electricity, is increasing year by year, the improvement of power generation efficiency can reduce power generation cost, reduce fossil fuel usage, and reduce air pollution due to combustion exhaust gas. It is a relevant and important issue. Given the current situation in which energy that has not been converted into electric power also causes hot drainage, there is a strong demand for the development of a power generation system that can efficiently recover electric power energy from combustion energy. Also,
As described above, a regenerative gas turbine for increasing the thermal efficiency of the gas turbine itself is also known, but it is required to further improve the thermal efficiency of the entire regenerative gas turbine. From this point of view, the technique relating to the regenerative gas turbine described in JP-A-5-33216 is useful for improving the thermal efficiency, but water is sprayed out of the thermal energy of the combustion exhaust gas from the gas turbine. The thermal energy in the temperature range lower than the temperature of the cooled compressed air will not be recovered.

The present invention has been made in view of the above-mentioned state of the art, and an object of the present invention is to provide an improved regenerative gas turbine power generation method having higher power generation efficiency as compared with the conventional regenerative gas turbine. .

[0006]

DISCLOSURE OF THE INVENTION The inventors of the present invention have studied in detail a regenerative gas turbine power generation system to achieve the above-mentioned object, and as a result, generated steam in exhaust gas after heating compressed air, By heating the steam with compressed air and supplying it to the combustor, the thermal efficiency of the regenerative gas turbine can be further increased, resulting in a reduction in the amount of waste energy and a dramatic improvement in the power generation efficiency of the entire system. This has led to the completion of the present invention.

That is, according to the present invention, a high temperature and high pressure combustion gas obtained by supplying compressed air and fuel to a combustor drives a gas turbine to generate electric power, and the combustion exhaust gas driving the gas turbine is equipped with a heat exchanger. In a power generation method by a regenerative gas turbine that is a heating source of compressed air supplied to a combustor of the gas turbine by guiding to a waste heat recovery boiler, steam is generated in the waste heat boiler that uses the combustion exhaust gas as a heat source, and After the steam is mixed with compressed air before heating, it is heated by a heat exchanger provided upstream in the waste heat recovery boiler and supplied to the combustor by a power generation method using a regenerative gas turbine. is there.

[0008]

According to the present invention, in the power generation by the regenerative gas turbine, the flue gas is used as the heat source, and the steam is first supplied and cooled by the heat exchanger provided upstream in the waste heat recovery boiler. By heating the mixed compressed air and using the residual heat after that to generate the steam, the heat energy of the combustion exhaust gas can be maximally recovered, and the recovered heat energy can be maximally utilized in the power generation of the gas turbine. This makes it possible to dramatically improve the thermal efficiency of the entire system.

The power generation method of the present invention will be described in detail below with reference to the drawings. FIG. 1 is an explanatory diagram showing an example of a power generation system according to the regenerative gas turbine power generation method of the present invention. Note that FIG. 1 shows only the main equipment and omits the auxiliary equipment.

In FIG. 1, the taken-in atmosphere 1 is compressed by an air compressor 2 into compressed air 5, which is guided to a heater (heat exchanger) 11 of a waste heat boiler 10 and heated together with a steam 14 as described later. The heated heated steam mixed compressed air 6 is sent to the combustor 4. Fuel 3 is supplied to the combustor 4. Although natural gas is preferable as the fuel, other hydrocarbon-containing fuel may be used as long as there is no quality problem such as heavy metal content. The combustion gas 7 of high temperature and high pressure generated in the combustor 4 has a pressure of about 1350 ° C and a pressure of 2
0ta, which is used to drive the gas turbine 9 and the rotational power of the turbine shaft is used for power generation.

In the power generation method of the present invention, since the constitution of the regenerative gas turbine system is adopted, the high temperature exhaust gas 8 of about 600 ° C. after the power discharged from the gas turbine 9 is taken out to the waste heat recovery boiler 10. The steam mixing compressed air 15 having a temperature of about 410 ° C., which is obtained by mixing the compressed air 5 compressed by the air compressor 2 and the steam 14 as described above, is heated by the heater 11. The feature of the present invention is that after heating the heater 11 using the combustion exhaust gas 8, the heater 13 for generating steam is further heated to generate steam 14 from the supplied water 12, and the steam 14 is mixed with the compressed air 5. Then, the steam mixed compressed air 15 is heated by the heater 11 and supplied to the combustor 4 as the heated steam mixed compressed air 6. The combustion exhaust gas after the steam 14 is generated has a relatively low temperature of about 160 ° C. and is emitted from the chimney 20.

As described in the above example, according to the power generation method of the present invention, the high-temperature heat energy of the combustion exhaust gas 8 can be recovered until the temperature reaches about 160 ° C., which can be maximized for power generation by the gas turbine 9. It can be used effectively, and the power generation efficiency is significantly improved. Further, according to the power generation method of the present invention, boiler water is usually used as the water 12 and is supplied to the compressed air 5. Therefore, piping for spraying water in the gas turbine power generation described in JP-A-5-332164. The problem of internal scale accumulation is almost eliminated.

Further, as is apparent from FIG. 1, the steam 14 is supplied to the compressed air 5 to mix the steam mixed compressed air 1
Since it is set to 5 and only needs to be heated, the apparatus used is relatively simple, and it is very advantageous from the viewpoint of installation cost.

Table 1 shows the results of the energy balance per unit amount of fuel (natural gas) calculated under specific conditions in the system of FIG. It can be seen from Table 1 that the system of FIG. 1 according to the method of the present invention can obtain high total power generation efficiency per unit fuel quantity.

[0015]

[Table 1]

[0016]

According to the present invention, the power generation efficiency can be remarkably improved only by improving a part of the system of the power generator using the regenerative gas turbine. High efficiency is
This is due to reduction of waste energy, which greatly contributes to reduction of combustion exhaust gas due to increase in power generation amount per unit fuel, and reduction of environmental pollution due to hot wastewater due to reduction of waste energy.

[Brief description of drawings]

FIG. 1 is an explanatory diagram showing an example of a regenerative gas turbine power generation system according to the method of the present invention.

Claims (1)

[Claims] 1. A waste gas provided with a heat exchanger, which drives a gas turbine with a high-temperature and high-pressure combustion gas obtained by supplying compressed air and fuel to a combustor to generate electric power, and with which a combustion exhaust gas that drives the gas turbine is provided with a heat exchanger. In a power generation method by a regenerative gas turbine that uses a compressed air as a heating source that is guided to a recovery boiler and is supplied to a combustor of the gas turbine, steam is generated in a waste heat boiler that uses the combustion exhaust gas as a heat source, and this steam is heated. A method of power generation by a regenerative gas turbine, characterized in that, after being mixed with the previous compressed air, it is heated by a heat exchanger provided upstream in a waste heat recovery boiler and supplied to the combustor.