JPH09195793A - Apparatus and method for energy conversion - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve heat efficiency and ratio output of a gas turbine cycle by reducing the gas temperature at the turbine inlet by supplying water into the combustor such that the gas temperature at the turbine inlet does not excess beyond the thermal resistance limit of the turbine. SOLUTION: The pression ratio of the condensor 1 and/or the fuel supply to the combustor 2 is increased while the condensate is supplied to the combustor 2, generated by condensing water vapor in the exhaust gas from a turbine 3. By the condensate supplied, the combustion temperature at the combustor 2 decreases so that the combustion gas temperature at the turbine 3 inlet decreases below the thermal resistance limit of the turbine. This forms a gas turbine cycle and a steam cycle in a mixed manner.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention generally relates to an energy conversion method and apparatus using a gas turbine cycle.

[0002]

BACKGROUND ART Japanese Patent Publication No. 55-45738 discloses a method of injecting water into a combustor of a gas turbine and lowering the temperature of the combustion gas by utilizing large latent heat of steam when the water changes into steam to exhaust the gas. It is disclosed to reduce NOx contained in the gas. Similarly, in Japanese Examined Patent Publication No. 5-88379, water or steam is injected into a combustor of a gas turbine,
There are indications that it was known to reduce NOx by lowering the combustion temperature. Further, in this publication, by injecting steam into the compressed air created by the compressor included in the gas turbine cycle, the mass weight of the compressed air increases, and as a result, the output generated by the gas turbine increases. There is a description that the point to be done was publicly known. The application of Japanese Patent Publication No. 5-88379 is
It is an application with a priority claim based on the US application dated July 22, 1985. Further, Japanese Patent Publication No. 6-5038 and Japanese Patent Publication No. 6-5039 disclose turbojet engines in which a part of a turbine stationary blade is replaced with a moving blade.

By the way, thermal efficiency and specific output are important as the performance of a gas turbine cycle such as a Brayton cycle. The thermal efficiency η is expressed by the following equation. η = 1- (Q2 / Q1) = 1- (1 / r) κ-1 / κ (1) where Q1: heat quantity supplied to the cycle, that is, heat quantity received in the cycle Q2: heat radiation quantity in the cycle r: pressure ratio κ: specific heat ratio. In the above formula (1), if the specific heat ratio κ is constant, the formula (1) becomes a function of only the pressure ratio r, and the larger the pressure ratio r, the higher the thermal efficiency η.

On the other hand, the specific output w can be defined by the output (Q1-Q2) per unit mass of the working fluid. If this specific output w is represented by thermal efficiency η, w = Q1-Q2 = Q1
Since x (1-Q2 / Q1) = Q1 · η, thermal efficiency η
Is constant, the larger the heat quantity Q1 supplied to the cycle, the larger the specific output w.

As can be understood from the above, in order to improve the thermal efficiency η, the pressure ratio r should be as large as possible, and in order to increase the specific output w, the heat quantity Q1 supplied to the cycle should be set. It should be as large as possible.

[0004]

However, this thermal efficiency η
In the actual design, and the specific output W are greatly restricted from the viewpoint of the heat resistance of the turbine. This problem is clearly pointed out in Japanese Examined Patent Publication No. 63-34292 and Japanese Examined Patent Publication No. 1-33648, but this problem will be described in detail below with reference to FIG.

FIG. 1 is a pv diagram of the Brayton cycle. The Brayton cycle, as is known, adiabatically compresses the working fluid entering the compressor at 1-2, supplies the heat quantity Q1 at a constant pressure to the cycle at 2-3, and adiabatically expands in the turbine at 3-4, The heat quantity Q2 is removed under constant pressure at 4-1.
The isotherm Td in FIG. 1 indicates the heat resistance limit temperature of the gas turbine. Here, the gas turbine is limited by a heat-resistant material, and it is generally considered that the gas temperature at the turbine inlet is limited to 700 ° C to 1000 ° C.

Therefore, in order to improve the thermal efficiency η, the pressure ratio r is set high, and the pressure P2 at the completion of adiabatic compression is set to P.
When increased to 2 ', even if the same amount of heat Q1 is supplied to the cycle, the temperature T3' at the point 3'when the heating process is completed approaches the turbine heat-resistant limit temperature Td or Td.
Beyond. Similarly, when the heat quantity Q1 supplied to the cycle is relatively increased, the temperature T3 ″ at the point 3 ″ at the time of completion of the heating process exceeds the turbine heat resistance limit temperature Td, which causes a problem of turbine destruction. I will end up.

Therefore, an object of the present invention is to provide an energy conversion method capable of improving the thermal efficiency of a gas turbine cycle and an apparatus for carrying out the method. Another object of the present invention is to provide an energy conversion method capable of improving the specific output of a gas turbine cycle and an apparatus for implementing the same. Another object of the present invention is to provide an energy conversion method capable of improving both the thermal efficiency and the specific output of a gas turbine cycle, and an apparatus for implementing the same.

[0008]

SUMMARY OF THE INVENTION The present invention is basically a gas turbine cycle in which a relatively large pressure ratio is set and / or the amount of heat supplied is relatively increased, and in a heating process in the gas turbine cycle, a combustor is used. A structure is adopted in which water is supplied to reduce the turbine inlet gas temperature so that the turbine inlet gas temperature does not exceed the turbine heat resistance limit temperature.

FIG. 2 is a diagram for explaining the basic concept of the present invention. In the figure, reference numeral 1 is a compressor, 2 is a combustor, and 3 is a turbine, and these elements 1 to 3 constitute the Brayton cycle 1-2-3-4 described in FIG. According to the present invention, water is supplied into the combustor 2 through the water conduit 4. The water supplied into the combustor 2 undergoes a phase change, that is, is vaporized by the combustion heat in the combustor 2 and removes the vaporization heat from the supply heat amount Q1. Even if it is set considerably higher than the above, the turbine inlet gas temperature T3 ′ can be kept lower than the turbine heat resistance limit temperature Td. This is the same when the supplied heat amount Q1 is considerably increased as compared with the conventional case, and similarly, when the supplied heat amount Q1 is increased while the pressure ratio r is set high, the phase change of water is similarly changed. Thus, the turbine inlet temperature can be kept lower than the turbine heat resistance limit temperature Td.

Further, since the steam vaporized in the combustor 2 enters the turbine 3 together with the combustion gas, the mass of the gas entering the turbine 3 is increased by the steam, and as a result, the output generated by the turbine 3 increases. .

Therefore, according to the present invention, the thermal efficiency η can be improved by setting the high pressure ratio r without being restricted by the heat resistance limit temperature of the turbine. Similarly, the supplied heat quantity Q can be obtained without being restricted by the heat resistance limit of the turbine.
1 can be increased to increase the specific output. Similarly, a high pressure ratio r can be set and the supplied heat quantity Q1 can be increased without being restricted by the heat resistance limit of the turbine, whereby the thermal efficiency η can be improved and the specific output can be increased.

When a turbine of the type in which some or all of the stationary blades are replaced by moving blades is adopted as the turbine 3 as disclosed in Japanese Patent Publication No. 6-5038, etc., the inside of the combustor 2 is The mass of gas that is transferred from the combustor 2 to the turbine increases due to the water injected into the
As a result, the momentum increases, so that the output that can be taken out by the turbine 3 can be increased.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION Various embodiments of the present invention will be described below with reference to the accompanying drawings. In each embodiment described next, the same reference numerals are used for the same elements as those described in FIG. 2 above, and the description thereof will be omitted.

First Embodiment (FIG. 3) In this embodiment, a water conduit 4 for supplying pressurized water to the combustor 2 is arranged, for example, in a spiral shape so as to surround the inside of the combustor 2, and the water conduit 4 is provided. The heat that tries to escape from the combustor 2 to the outside is taken in by the pressurized water passing through. Originally, the heat escaping from the combustor 2 to the outside is captured by the water passing through the water conduit 4, and the captured heat is returned to the combustor 2 through the water supplied from the water conduit 4 into the combustor 2. be able to. Therefore, it is possible to suppress a decrease in the thermal efficiency η due to the heat loss of the combustor 2.

Second Embodiment (4th and 5th Embodiments ) In this embodiment, as shown in FIG. 4, a heat exchanger 5 is arranged in an exhaust passage of a turbine 3, and a water pipe 4 is provided in the heat exchanger 5. Are connected to recover the heat contained in the exhaust gas. As a modified example thereof, as shown in FIG. 5, a water conduit 4 is attached to a heat exchanger 5 arranged in an exhaust passage of a turbine 3.
The water pipe 4 is arranged so as to surround the inside of the combustor 2, and the heat contained in the exhaust gas is recovered via the pressurized water passing through the water pipe 4 and is also transmitted from the combustor 2 to the outside. The heat to escape may be captured and returned to the combustor 2.

Third Embodiment (FIGS. 6 to 8) A closed system is created by condensing water vapor contained in exhaust gas emitted from a turbine 3 and returning the condensed water to a combustor 2 through a water conduit 4. be able to. The system will then form a steam cycle (eg, Rankine cycle).

An example thereof is shown in FIG. In the system shown in the figure, a heat exchanger 5 is provided in the exhaust system of the turbine 3, and the steam in the exhaust gas is condensed by the heat exchanger 5,
The condensed water generated as a result passes through the water conduit 4 to the combustor 2
Supplied in. According to this system, the heating process and the expansion process are common processes of the gas turbine cycle and the steam cycle. With such a configuration, compared to the case where the gas turbine cycle and the steam cycle are independently produced, the configuration of the entire system can be made compact, and two such thermodynamic cycles can be performed. The effective combination can continuously improve both the thermal efficiency and the specific output of the gas turbine cycle. The hot water obtained in the heat exchanger 5 may be used for other purposes through the conduit 6.

When the condensed water is supplied to the combustor 2 through the water conduit 4, the water conduit 4 is arranged in a spiral shape so as to surround the inside of the heater 2, as shown in FIG. The heat that tries to escape from the combustor 2 to the outside may be captured by the condensed water that passes through. According to this, the heat that originally escapes from the combustor 2 can be captured by the condensed water that passes through the water conduit 4, and the captured heat can be returned to the combustor 2.

To condense the water vapor in the exhaust gas, FIG.
As shown in, the radiator 7 may be used, and the water condensed by the radiator 7 may be returned to the inside of the combustor 2 by passing around the heat exchanger 5 and / or the combustor 2 of the exhaust system. Further, as shown in FIG. 8, water may be supplied to the combustor 2 through two paths, a path 8 for supplying new water and a path 9 for circulating water.

When the condensed water is returned to the heater 2, the turbine 3
It is preferable to set the exhaust gas temperature to 100 ° C. in the vicinity of the outlet in order to easily obtain condensed water. Further, it is desirable that the steam passing through the turbine 3 is superheated steam in order to prevent corrosion of the turbine material.

The amount of air supplied to the combustor 2 is preferably adjusted so as to obtain the stoichiometric air-fuel ratio. According to this,
Minimum air (oxygen) for combustion of fuel supplied to combustor 2
Is supplied, and since the combustion temperature can be sufficiently suppressed by utilizing the phase change of the water, combustion is performed with the maximum fuel being supplied on the basis of air, and a large specific output is obtained. Easy to get.

That is, when the fuel is burned at the stoichiometric air-fuel ratio, the amount of fuel becomes maximum when considering air as a reference, and compared with the case where the fuel is burned at an air-fuel ratio larger than the theoretical air-fuel ratio,
The turbine inlet temperature becomes high, and a large amount of heat supply is obtained. By supplying water as described above, it is possible to lower the turbine inlet temperature and obtain a large specific output.

The embodiment of the present invention has been described above.
The turbine 3 used for this may be an impulse turbine, or a turbine in which some or all of the stationary blades are replaced with moving blades.

[Brief description of the drawings]

FIG. 1 is a diagram for explaining a problem of the present invention.

FIG. 2 is a diagram for explaining the basic concept of the present invention.

FIG. 3 is an overall configuration diagram showing a first embodiment of the present invention.

FIG. 4 is an overall configuration diagram showing a second embodiment of the present invention.

FIG. 5 is an overall configuration diagram showing a modified example of the second embodiment.

FIG. 6 is an overall configuration diagram showing an example of a third embodiment of the present invention.

FIG. 7 is an overall configuration diagram showing another example of the third embodiment of the present invention.

FIG. 8 is an overall configuration diagram showing another example of the third embodiment of the present invention.

[Explanation of symbols]

 1 Compressor 2 Combustor 3 Turbine 4 Water pipe 7 Radiator

Claims (16)

[Claims] 1. A pressure ratio is increased in a compression process which is one stroke of a gas turbine cycle and / or a supplied heat amount is increased in a heating process after the compression process, while water is supplied in the heating process, An energy conversion method, wherein the turbine inlet temperature at the end point of the heating process is set to be equal to or lower than the turbine heat resistance limit temperature. 2. The method of claim 1, wherein the heat input is produced by burning a fuel. 3. The method according to claim 2, wherein the combustion of the fuel is performed at a stoichiometric air-fuel ratio. 4. The method according to any one of claims 1 to 3, wherein the working fluid in the gas turbine cycle is transferred to the heat radiation process while being lowered to around 100 ° C. 5. The method according to claim 1, wherein in the heat dissipation process, water vapor in the working fluid is condensed to generate condensed water. 6. The method according to claim 5, wherein the condensed water is used for supplying water in the heating process. 7. The method according to claim 6, wherein the condensed water is heated by the heat released to the outside in the heating step, and the heated condensed water is used for supplying water in the heating step. 8. The heat dissipation process heats the condensed water with the heat contained in the exhaust gas, and the heated condensed water is used for supplying water in the heating process. The method described in. 9. A compressor for compressing air set to a relatively high pressure ratio, a combustor for supplying fuel to the compressed air flowing out from the compressor to perform combustion, and a combustor for combusting the compressed air. An energy conversion device comprising: a turbine that obtains an output from the emitted combustion gas; and a water supply unit that supplies water into the combustor so that the combustion gas temperature is equal to or lower than a turbine heat-resistant limit temperature. 10. A compressor for compressing air, a combustor for supplying a relatively large amount of fuel to the compressed air flowing out from the compressor for combustion, and a combustion gas discharged from the combustor. An energy conversion device comprising: a turbine that obtains an output; and a water supply unit that supplies water into the combustor so that a combustion gas temperature is equal to or lower than a turbine heat resistance limit temperature. 11. A compressor for compressing air set to a relatively large pressure ratio, and a combustor for supplying a relatively large amount of fuel to the compressed air flowing out from the compressor for combustion. An energy conversion device comprising: a turbine that obtains an output from combustion gas emitted from the combustor; and a water supply pipe that supplies water into the combustor so that a combustion gas temperature is equal to or lower than a turbine heat resistance limit temperature. 12. A radiator provided downstream of the turbine for guiding exhaust gas to the outside is further provided, and the exhaust gas temperature near the outlet of the turbine is set to about 100.degree. The energy conversion device according to any one of claims 9 to 11. 13. The exhaust gas temperature near the entrance of the radiator is set to be about 100 ° C.
The energy conversion device according to claim 11. 14. The energy conversion system according to claim 12, wherein the water supply pipe receives condensed water obtained by condensing water vapor in exhaust gas emitted from the turbine and supplies the condensed water into the combustor. apparatus. 15. The energy conversion device according to claim 14, wherein the water supply pipe is spirally arranged around the combustor. 16. The energy conversion device according to claim 9, wherein the turbine is a turbine of a type in which a stationary blade is replaced with a moving blade.