JP3160469B2 - Power control method and apparatus for closed Brayton cycle gas turbine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for controlling the output of a closed Brayton cycle gas turbine using a mixed gas of a high molecular weight gas and a low molecular weight gas.

[0002]

FIG. 23 shows a conventional Closed Brayton Cycle Gas-Turbin.
This is a system diagram of e). As the working gas, as shown in Table 1, a mixed gas of a large molecular weight gas 13, for example, xenon (Xe) and a small molecular weight gas 14, for example, helium (He) is used.

The closed Brayton cycle gas turbine comprises a gas compressor 7 mounted on an output shaft 16 of a gas turbine 6, a regenerative heat exchanger 9 for preheating high-pressure gas by exhaust heat of the gas turbine, and a regenerator 9 for preheating high-pressure gas. Heater 8,
It comprises a gas turbine exhaust gas cooler 10 and an air storage tank 11 ′ that regulates the amount of working gas circulated according to the load on the gas turbine 6.

[0004]

[Table 1]

In this closed Brayton cycle gas turbine, the mixed gas 13+ pressurized by the gas compressor 7
Numeral 14 is heated by the regenerative heat exchanger 9 and the heater 8, and the turbine 6 generates driving force and output of the gas compressor 7. The mixed gas 13 + 14, which has been reduced in temperature and reduced in pressure in the turbine 6, supplies heat to the low-temperature and high-pressure side in the regenerative heat exchanger 9 and the cooler 1
Heat is released at 0, and the pressure is again increased by the gas compressor 7 to form a closed cycle.

When switching to a low output, the opening of the introduction valve 1 is adjusted with the exhaust valve 2 closed, a part of the high-pressure gas is stored in the storage tank 11 ', and the weight flow rate of the mixed gas 13 + 14 is changed. . At the same time, the heat input Q of the heater 8 is also reduced. When switching to high output, the opening of the exhaust valve 2 is adjusted with the introduction valve 1 closed, and the high-pressure gas stored in the air storage tank 11 'is exhausted into the cycle. At the same time, the heat input Q of the heater 8 is also increased.

In this conventional method, when the weight flow rate of the working gas is changed, the volume flow rate of the working gas also changes. Therefore, the output control is performed by changing the pressure ratio of the cycle. The air storage tank 11 'of the conventional output control device has only a function of storing air.

[0008]

As described above, in the conventional closed Brayton cycle gas turbine, the air storage tank 11 'of the output adjustment device has only a function of storing air. In addition, the volume flow rate changes at the time of evacuation, and the pressure ratio of the cycle changes. On the other hand, the relationship between cycle efficiency, which indicates cycle performance, and pressure ratio is:
As shown in FIG. 15, there is a relationship in which the efficiency becomes maximum near the pressure ratio of about 2.

Therefore, in the conventional output adjustment method, there is a concern that the cycle efficiency greatly changes at each load point, and that the cycle efficiency is reduced particularly at a low load. It is an object of the present invention to provide a control method and a control device that can control the output of a closed Brayton cycle gas turbine without changing the cycle efficiency.

[0010]

SUMMARY OF THE INVENTION The present invention is directed to a closed Brayton cycle gas turbine using a mixed gas of a large molecular weight gas and a small molecular weight gas. While separating a part of the high molecular weight gas inside, storing the low molecular weight gas after the separation of the high molecular weight gas, the separated high molecular weight gas and the stored low molecular weight gas are separated according to the output of the gas turbine. A method of controlling the output by recirculating at least one of them into the cycle is adopted.

In this case, in order to separate the high molecular weight gas, an adsorbent for absorbing the high molecular weight gas, a gas permeable membrane for blocking the high molecular weight gas, or the high molecular weight gas is liquefied and separated by a liquefier. Such means can be used.

Alternatively, a centrifugal compressor is used as a compressor for compressing a mixed gas of a high molecular weight gas and a small molecular weight gas, and a part of the high-pressure gas discharged from the centrifugal compressor is discharged from the outer periphery of the discharge side scroll of the centrifugal compressor. By taking out, high-molecular-weight gas can be separated using the centrifugal force of the high-pressure gas.

That is, in the mixed gas discharged from the centrifugal compressor, a large molecular weight gas is unevenly distributed on the outer peripheral portion of the discharge scroll due to the centrifugal force. Can separate large molecular weight gas.

In the output control method of the closed Brayton cycle gas turbine according to the present invention, as described above, the separation of the high molecular weight gas in the mixed gas as the working fluid, the recirculation into the cycle, and the storage of the low molecular weight gas are performed. The output can be adjusted by changing the average molecular weight of the working fluid mixed gas by appropriately performing the exhaust.

For example, when reducing the output, a part of the high-pressure gas discharged from the gas compressor is put into an adsorption tank filled with an adsorbent to adsorb the high molecular weight gas, and the separated small molecular weight gas is put into the cycle. Return to reduce the weight flow rate of the mixed gas.

On the other hand, when the output is increased, the weight flow rate of the mixed gas is increased by desorbing the large molecular weight gas adsorbed on the adsorbent and returning the gas into the cycle.
As described above, according to the output control method of the present invention, the weight flow rate is adjusted by changing the mixing ratio of the mixed gas according to the output of the gas turbine, and the pressure efficiency is maintained substantially constant without largely changing the cycle efficiency. The output can be controlled.

Further, for example, when a large molecular weight gas is separated by using a gas permeable membrane that blocks a part of the large molecular weight gas, the separation of the large molecular weight gas in the mixed gas as a working fluid by the permeable membrane is also required. By appropriately performing the reflux into the cycle and the storage of the permeated small molecular weight gas and the reflux into the cycle, the output can be adjusted in the same manner as described above by changing the average molecular weight of the working fluid mixed gas.

Further, the present invention provides a closed Brayton cycle gas turbine using a mixed gas of a high molecular weight gas and a low molecular weight gas as an output control device for solving the above-mentioned problem, which is branched from a discharge line of a gas compressor. A gas separation tank for separating large molecular weight gas, a reservoir tank for storing small molecular weight gas separated and discharged from this gas separation tank, and a pipe line connecting these tanks and the cycle are adopted. .

The gas separation tank is provided with an adsorbent for adsorbing a high molecular weight gas or a gas permeable membrane for shutting off a high molecular weight gas, a liquefaction apparatus for liquefying a high molecular weight gas, and the like. It is possible to adopt a configuration in which the separated large molecular weight gas is stored.

Alternatively, a gas centrifugal compressor is used for compressing the mixed gas, and the gas centrifugal compressor is branched off from the outer periphery of the scroll on the discharge side of the gas centrifugal compressor to store a large molecular weight gas. A configuration is adopted in which a reservoir tank is provided branched from the inner periphery of the scroll and stores the small molecular weight gas, and a conduit for communicating each tank with the inside of the cycle is provided.

According to this output control device, by separating and storing the high molecular weight gas in the gas separation tank, the component of the low molecular weight gas can be increased without reducing the volume flow rate of the mixed gas. Therefore, since the weight flow rate can be reduced without changing the pressure ratio, the output can be reduced without changing the cycle efficiency.

Further, by returning the high molecular weight gas separated in the gas separation tank into the cycle, the mixed gas component can be returned to the original state without increasing the volume flow rate of the mixed gas. Therefore, since the weight flow rate can be increased without changing the pressure ratio, the output can be increased without changing the cycle efficiency.

[0023]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of a control method according to the present invention and a control device according to one embodiment of the present invention will be specifically described below with reference to the accompanying drawings. In the following drawings, FIG.
The same parts as those of the configuration of the conventional closed Brayton cycle gas turbine shown in FIG. 3 are denoted by the same reference numerals for the sake of simplicity of description, and redundant description thereof will be omitted.

(First Embodiment) First, the configuration of a closed Brayton cycle gas turbine provided with a control device according to an embodiment of the present invention will be described with reference to FIG. In the closed Brayton cycle gas turbine shown in FIG.
Unlike the conventional example in FIG. 16, the air storage tank 1 in FIG.
1 ′ is an adsorption tank 11 filled with an adsorbent 15 (for example, A-type zeolite), and a reservoir tank 12 provided outside the system and the adsorption tank 11 are communicated via a recovery valve 4.

In the apparatus shown in FIG. 1, a pipe connecting the reservoir tank 12 to the inlet line of the gas turbine 6 via the recovery valve 4 and the return valve 3 is provided, and the gas from the reservoir tank 12 via the supply valve 5 is provided. A pipe connecting to the inlet line of the compressor 7 is provided. The other configuration is the same as the conventional one shown in FIG. Next, an operation state of how the output control is performed in the closed Brayton cycle gas turbine shown in FIG. 1 will be described with reference to FIGS.

FIG. 2 shows the operating state of the gas turbine 6 at the planned maximum load (output). Since all of the valves 1 to 5 are closed, the valve 1 in the prior art shown in FIG. , 2 in the closed state.

3) In FIG. 3, as the first stage of the output reduction, a part of the high-pressure gas discharged from the gas compressor 7 is supplied to the valve 1 in order to reduce the overall weight flow while keeping the gas mixture ratio.
Is opened and guided into the adsorption tank 11, the large molecular weight gas 13 is adsorbed by the adsorbent 15, and the separated small molecular weight gas 14 is stored in the reservoir tank 12 via the recovery valve 4.
Valves 2, 3, and 5 remain closed.

(C) In FIG. 4, the supply valve 5 is opened and the small molecular weight gas 14 stored in the reservoir tank 12 in (b) above.
Is returned into the cycle, the mixed molecular weight is reduced by this operation, and the output of the gas turbine 6 is reduced. Valves 1-4 are closed.

5) FIG. 5 shows an operation state in the case where the output is further reduced. The introduction valve 1 is opened, the working gas is led to the adsorption tank 11, and the high molecular weight gas 13 in the working gas is taken into the adsorbent 15. By adding the separated small molecular weight gas 14 into the cycle by opening the valve 3, the mixed molecular weight is further reduced. Valves 2, 4, and 5 are closed.

(E) In FIG. 6, by opening the exhaust valve 2 at the outlet of the adsorption tank 11, the pressure in the adsorption tank 11 is reduced, and the large molecular weight gas 13 adsorbed by the adsorbent 15 is removed. Desorbed and returned in the cycle,
The mixed molecular weight of the cycle increases and the gas turbine output increases. Valves 2-5 are closed.

As described above, in the closed Brayton cycle gas turbine shown in FIG.
4,5 closed, valves 1,3 open ⇒valves 1,3 closed ⇒valve 5
By opening, the component of the small molecular weight gas 14 can be increased without decreasing the volume flow rate of the mixed gas. Therefore, since the weight flow rate can be reduced without changing the pressure ratio, the output can be reduced without changing the cycle efficiency.

Further, valves 1, 3, 4, 5 are closed, and valve 2 is
By opening ⇒ closing valve 2 ⇒ opening valves 1 and 4 ⇒ closing valves 1 and 4 ⇒ opening valve 2, the mixed gas component can be returned to the original without increasing the volume flow rate of the mixed gas. Therefore, since the weight flow rate can be increased without changing the pressure ratio, the output can be increased without changing the cycle efficiency.

(Second Embodiment) Next, an embodiment in which a large molecular weight gas is separated by using a gas permeable membrane will be described with reference to FIGS.
This will be described with reference to FIG. The second embodiment shown in FIGS. 7 to 13 is different from the apparatus according to the first embodiment shown in FIGS. 1 to 6 in that a large molecular weight gas adsorbent 15 On the other hand, in the second embodiment, a gas permeable membrane 25 (for example, made of cylindrical polyethylene, which allows gas to permeate from the inside of the cylinder to the outside of the cylinder) is provided in the gas separation tank 11 to block large molecular weight gas. That is, several modules are installed). Other configurations are the same as those of the first embodiment. The operation of the thus constructed device according to the second embodiment will be described below with reference to FIGS.

FIG. 8 shows the state of the planned maximum load (output) of the gas turbine 6, in which the valves 1 to 5 are closed, so that the conventional introduction valve 1 and exhaust valve 2 in FIG. Is the same.

FIG. 9 shows, as a first stage of the output reduction, a part of the high-pressure gas discharged from the gas compressor 7 through the introduction valve 1 and the gas separation tank 11 in order to reduce the overall weight flow rate.
The high molecular weight gas 13 is blocked by the gas permeable membrane 25, and the permeated and separated small molecular weight gas 14 is returned to the cycle via the return valve 3. Since the high molecular weight gas 13 is stored in the gas separation tank 11, the mixed molecular weight of the mixed gas decreases, but the volume flow rate also slightly decreases.

FIG. 10 shows the second stage of the output reduction, in which the small molecular weight gas 14 previously stored in the reservoir tank 12 is cut off by the gas separation tank 11, and the volume of the stored high molecular weight gas 13 is integrated into a cycle. By returning, the mixed molecular weight of the mixed gas is further reduced without changing the volume flow rate, and the output of the gas turbine 6 is reduced.

(D) FIG. 11 shows that the large molecular weight gas 13 which has been separated and stored in the gas separation tank 11 by opening the exhaust valve 2 in order to increase the overall weight flow rate as the first stage of the output recovery is low pressure. Return to the side cycle. A lot
In this case, the mixed molecular weight of the mixed gas is still in the original state (Fig. 8).
Not returned (smaller than in original state).

FIG. 12 shows, as the second stage of the output recovery, in order to return the mixed molecular weight of the mixed gas to the original state (FIG. 8), the introduction valve 1 is opened again to permeate and separate the mixed gas, and the excess small molecular gas 14 is removed. From the collection valve 4 to the reservoir tank 12 to be stored. However, since the high molecular weight gas 13 is stored in the gas separation tank 11, the mixed molecular weight of the mixed gas does not return to the original state (FIG. 8).

FIG. 13 shows that the exhaust valve 2 is opened again as the third stage of the output recovery, the large molecular weight gas 13 in the gas separation tank 11 is returned to the low pressure side cycle, and the mixed molecular weight of the mixed gas increases, (FIG. 8), that is, the gas turbine output at the planned maximum load (output).

(Third Embodiment) Next, an embodiment in which a high molecular weight gas is separated using a liquefaction apparatus will be described with reference to FIG. In the third embodiment, a liquefaction device 35 is provided in the gas separation tank 11 for liquefying and separating a large molecular weight gas. Other configurations are the same as those of the first and second embodiments described above.

The operation of the thus constructed device according to the third embodiment will be described below. When the valves 2, 4, and 5 are closed and the valves 1 and 3 are open, the mixed gas 13 + 14 flows into the gas separation tank 11, and the high molecular weight gas 13 of the mixed gas is liquefied by the liquefaction unit 35 and separated. Next, the valves 1 and 3 are closed, the valve 5 is opened, and the small molecular weight gas 14 corresponding to the volume of the liquefied large molecular weight gas is replenished from the reservoir tank 12 to reduce the weight flow rate without changing the pressure ratio, that is, reduce the output. Has the effect of causing.

When the liquefied gas 13 having a large molecular weight is vaporized and the valves 1, 3, 4, 5 are closed and the valve 2 is opened, the gas 13 having a large molecular weight returns to the cycle. When the valve 2 is closed and the valves 1 and 4 are opened, the gas is separated again by the liquefaction unit 35, and the small molecular gas 14 is returned to the large molecular gas 1 in the cycle.
3 is collected in the volume reservoir tank 12. The valves 1 and 4 are closed, the valve 2 is opened, and the liquefied large molecular weight gas 13 is vaporized again and returned into the cycle, thereby increasing the weight flow rate without changing the pressure ratio, that is, increasing the output. .

(Fourth Embodiment) Next, a fourth embodiment in which a large molecular weight gas is separated by using a centrifugal force of a gas centrifugal compressor will be described with reference to FIGS. As can be seen in FIG. 15, the centrifugal compressor 1 shown in FIG.
7 is used. Then, a pipe 19 branched from the outer periphery of the discharge-side scroll 18 of the compressor 17 is connected to the separation gas tank 21 via the introduction valve 1.

The pipe 20 branched from the inner periphery of the discharge scroll is connected to the reservoir tank 12 via the recovery valve 4. The separation gas tank 21 used in the fourth embodiment does not perform the gas separation operation unlike the previous embodiment, but only stores gas. Other configurations are the same as those in the previous embodiment. The operation of the fourth embodiment having the above configuration will be described with reference to FIGS.

(A) FIG. 16 shows a state at the time of the planned maximum load (output) of the gas turbine 6, and since the valves 1 to 5 are closed, the valves 1 and 2 in the conventional apparatus shown in FIG.
Is the same as the closed state.

(B) FIG. 17 shows the state of the first stage of the output reduction. In order to reduce the weight flow rate of the whole mixed gas, of the high-pressure gas discharged from the centrifugal compressor 17, the large molecular weight gas 1
Part 3 is separated from the separation gas tank 2 through the introduction valve 1 from the pipe 19 on the outer peripheral side of the scroll 18 using centrifugal force.
1 and the small molecular weight gas 14
Return into cycle via 8. Since the high molecular weight gas 13 is stored in the separation gas tank 21, the mixed molecular weight of the mixed gas decreases, but the volume flow rate also slightly decreases.

(C) FIG. 18 shows the state of the second stage of the output reduction in which the small molecular weight gas 14 previously stored in the reservoir tank 12 is cycled by the volume integral of the large molecular weight gas 13 stored in the separation gas tank. By returning to the inside, the mixed molecular weight of the mixed gas is further reduced without changing the volume flow rate, and the output of the gas turbine is reduced.

(D) FIG. 19 shows the state of the first stage of the output recovery, in which the exhaust valve 2 is opened to increase the total weight flow rate, and the large molecular weight separated and stored in the separation gas tank 21 by opening the exhaust valve 2. The gas 13 returns into the low pressure cycle.
However, in this case, the mixed molecular weight of the mixed gas has not yet returned to the original state (FIG. 16) (smaller than the original state).

(E) FIG. 20 shows the state of the second stage of the output recovery, in which the mixed molecular weight of the mixed gas is returned to the original state (FIG. 16). The air is guided from the pipe 20 on the inner peripheral side of the scroll 18 to the reservoir tank 12 via the recovery valve 4 and stored therein. With the above operation, the gas turbine output is restored to the original state (FIG. 16), that is, the gas turbine output at the time of the planned maximum load (output).

[0050]

As described above, according to the present invention, a part of the high molecular weight gas in the mixed gas discharged from the gas compressor is separated, and the low molecular weight gas after the separation of the high molecular weight gas is stored. Keeping in mind, depending on the output of the gas turbine, the separated large-molecular-weight gas and the stored small-molecular-weight gas are recirculated into at least one of the cycles to change the mixed gas ratio and keep the pressure ratio almost constant. While changing the weight flow rate, the output of the closed Brayton cycle gas turbine can be controlled.

[Brief description of the drawings]

FIG. 1 is a system diagram of a closed Brayton cycle gas turbine including an output control device according to a first embodiment of the present invention.

FIG. 2 is a system diagram showing an operation state of the closed Brayton cycle gas turbine shown in FIG. 1 at a planned maximum load.

FIG. 3 is a system diagram showing an operation state when the output of the closed Brayton cycle gas turbine shown in FIG. 1 is reduced.

FIG. 4 is a system diagram showing an operation state when the output is further reduced from the operation state shown in FIG. 3;

FIG. 5 is a system diagram showing an operation state when the output is further reduced from the operation state shown in FIG. 4;

FIG. 6 is a system diagram showing an operation state when the output is increased from the operation state shown in FIG. 5;

FIG. 7 is a system diagram of a closed Brayton cycle gas turbine including an output control device according to a second embodiment of the present invention.

8 is a system diagram showing an operation state of the closed Brayton cycle gas turbine shown in FIG. 7 at a planned maximum load.

FIG. 9 is a system diagram showing an operation state of a first stage of output reduction in the closed Brayton cycle gas turbine shown in FIG. 7;

FIG. 10 is a system diagram showing an operation state when the output is further reduced to the second stage from the operation state shown in FIG. 9;

FIG. 11 is a system diagram showing a first-stage operation state in which the output has been recovered from the operation state shown in FIG. 10;

12 is a system diagram showing an operation state when the output is further increased to a second stage from the operation state shown in FIG. 11;

FIG. 13 is a system diagram showing an operation state when the output is further restored to the third stage from the state shown in FIG. 12;

FIG. 14 is a system diagram of a closed Brayton cycle gas turbine including an output control device according to a third embodiment of the present invention.

FIG. 15 is a system diagram of a closed Brayton cycle gas turbine including an output control device according to a fourth embodiment of the present invention.

16 is a system diagram showing an operation state of the closed Brayton cycle gas turbine shown in FIG. 15 at a planned maximum load.

17 is a system diagram showing an operation state of a first stage of output reduction in the closed Brayton cycle gas turbine shown in FIG.

FIG. 18 is a system diagram showing an operation state when the output is reduced to a second stage from the operation state shown in FIG. 17;

FIG. 19 is a system diagram showing a first-stage operation state in which output has been recovered from the operation state shown in FIG. 18;

20 is a system diagram showing an operation state when the output is further increased to the second stage from the operation state shown in FIG. 19;

FIG. 21 is a perspective view showing a part A of FIG.

FIG. 22 is a graph showing a relationship between cycle efficiency and pressure ratio in a closed Brayton cycle gas turbine.

FIG. 23 is a system diagram of a conventional closed Brayton cycle gas turbine.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Introduction valve 2 Exhaust valve 3 Return valve 4 Recovery valve 5 Supply valve 6 Gas turbine 7 Gas compressor 8 Heater 9 Regenerative heat exchanger 10 Cooler 11 Gas separation tank 12 Reservoir tank 13 Large molecular weight gas 14 Small molecular weight gas 15 Adsorption Agent 17 Centrifugal compressor 18 Scroll 19 Pipe provided on the outer circumference of souksul 20 Pipe provided on inner circumference of souksul 21 Separation gas tank 25 Gas permeable membrane 35 Liquefaction device

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-4-101024 (JP, A) JP-A-59-206617 (JP, A) JP-A-57-210129 (JP, A) JP-A-3- 111625 (JP, A) (58) Field surveyed (Int. Cl. ⁷ , DB name) F02C 1/10 F01K 25/06

Claims (6)

(57) [Claims] In a closed Brayton cycle gas turbine using a mixed gas of a high molecular weight gas and a low molecular weight gas, a part of the high molecular weight gas in the mixed gas discharged from a gas compressor is separated and the large gas is separated. The low molecular weight gas after the separation of the high molecular weight gas is stored, and at least one of the separated high molecular weight gas and the stored low molecular weight gas is refluxed into the cycle and mixed according to the output of the gas turbine. A method for controlling the output of a closed Brayton cycle gas turbine, wherein the weight ratio is changed while changing the gas ratio and maintaining the pressure ratio substantially constant. 2. The method for controlling the output of a closed Brayton cycle gas turbine according to claim 1, wherein the separation of the high molecular weight gas is performed using any one of an adsorbent, a gas permeable membrane, and a liquefier. 3. A centrifugal compressor is used as the gas compressor, and the separation of the large molecular weight gas is performed by utilizing the centrifugal force of the high pressure gas discharged from the centrifugal compressor. The output control method for a closed Brayton cycle gas turbine according to claim 1, wherein 4. A closed Brayton cycle gas turbine using a mixed gas of a high molecular weight gas and a low molecular weight gas, wherein a gas separation tank is provided which is branched from a discharge line of a gas compressor and separates the high molecular weight gas. An output control device for a closed Brayton cycle gas turbine, comprising: a reservoir tank for storing small molecular weight gas separated and discharged from a gas separation tank; and a pipeline communicating with each of the tanks in the cycle. 5. The closed vessel according to claim 4, wherein one of an adsorbent for a large molecular weight gas, a gas permeable membrane for blocking the large molecular weight gas, and a liquefaction device for liquefying the large molecular weight gas is provided in the gas separation tank. Brayton cycle gas turbine output control device. 6. A closed Brayton cycle gas turbine using a mixed gas of a large molecular weight gas and a small molecular weight gas, which is provided by branching from the outer periphery of a scroll on a discharge side of a gas centrifugal compressor, and stores the large molecular weight gas. A gas separation tank, which is disposed branched from the inner periphery of the scroll,
An output control device for a closed Brayton cycle gas turbine, comprising: a reservoir tank for storing the small molecular weight gas; and a conduit communicating with each of the tanks in the cycle.