JPH08338398A - Variable flow rate ejector - Google Patents

Abstract

PURPOSE: To obtain a variable flow rate ejector which can maintain the suction rate almost at a constant value even though the flow rate of a high pressure driving gas is reduced, and thereby, can suck a low pressure driven gas almost proportional to the flow rate reduction of the high pressure driving gas. CONSTITUTION: This variable flow ejector consists of a venturi tube 18 having a throat part 18a communicating to a low pressure gas 2; an injection nozzle 19 to inject a high pressure gas 6 in the axial direction of the venturi tube 18; and a flow rate regulating device 20 to convert the opening area of the injection nozzle 19. The flow rate regulating device 20 is inserted to a circular nozzle movable in the axial direction, and it consists of a cylindrical regulating rod 20a having a conical part opposing to the circular nozzle, and a driving device 20b to move the regulating rod 20a in the axial direction.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a variable flow ejector, and more particularly to a two-fluid cycle gas turbine used in the field of gas turbine cogeneration for generating electric power (or power) and steam to realize energy saving. Variable flow ejector used for

[0002]

2. Description of the Related Art As a two-fluid cycle gas turbine for injecting steam into a gas turbine, for example, Japanese Patent Publication No. 54-3
No. 4865, "Two Working Fluid Heat Engine" is known. This two-fluid cycle gas turbine (hereinafter referred to as a chain cycle from the inventor's name) has a throttle valve 51, a compressor 52, a combustion chamber 5 as shown in FIG.
3, water treatment device 54, pump 55, heat exchanger 56, turbines 57, 58, condenser 59, etc.,
Air sucked from the atmosphere is compressed by the compressor 52 and supplied to the combustion chamber 53, and the compressed air burns fuel to generate high-temperature combustion gas. The combustion gas drives the turbines 57 and 58 to compress the air. 52 and the load, and further the heat exchanger 5 by the combustion gas leaving the turbine.
Water vapor is generated in 6 and water is collected in the condenser 59 and released into the atmosphere. In the chain cycle, since the steam S generated in the heat exchanger 56 is injected into the combustion chamber 53, the flow rate of the combustion gas flowing into the turbine is increased, and the specific heat of the combustion gas is increased. Therefore, the turbine output and thermal efficiency are increased. It has a feature that can increase.

However, the above-mentioned two-fluid cycle gas turbine (Chain cycle) has a problem that the steam S supplied (injected) to the combustion chamber 53 needs to be superheated steam. That is, in the chain cycle, if saturated steam, not superheated steam, is supplied to the combustion chamber, there is a problem that vapor drain occurs due to slight heat dissipation and erosion occurs in pipes and combustion chambers. To supply, for example, the exhaust gas outlet of the gas turbine and the heat exchanger 56
It is necessary to provide a superheater between the (exhaust heat boiler) or inside the heat exchanger 56, which impairs the compactness of the two-fluid cycle gas turbine, complicates the system, and causes an excessive manufacturing cost. It was

In order to solve such a problem, the inventor of the present application directly uses saturated steam without using a superheater, and is capable of simultaneously increasing turbine output and thermal efficiency without generating steam drain. Developed and applied for a cycle gas turbine (Japanese Patent Application No. 6-201187, unpublished). In this application, the well-known ejector 60 illustrated in FIG. 4A is used as a mixer, the saturated steam S is used as a drive source to suck hot compressed air, and the saturated steam is heated by the compressed air to be superheated steam, Moreover, the degree of heating was further increased by decreasing the vapor partial pressure.

FIG. 4B is a test example of such means, in which the ejector 60 is driven by the saturated steam S from the boiler to suck the low-pressure high-temperature air, and the downstream portion is irradiated with the red laser light. The trajectory was observed. As a result, in the case of only steam, the trajectory of the laser light can be visually observed due to the presence of saturated vapor, and when high temperature air is sucked, the vapor becomes heating vapor, so that the trajectory of the laser light cannot be visually observed. It was confirmed that the saturated steam can be heated to become superheated steam.

[0006]

However, in the conventional ejector 60 illustrated in FIG. 4, when the flow rate of the high-pressure driving gas (for example, saturated vapor) is reduced, the suction efficiency sharply decreases,
There is a problem that the low-pressure driven gas (for example, high temperature air) can hardly be sucked. That is, in the conventional ejector of FIG. 4 (A), when the flow rate of the high-pressure drive gas for the ejector is reduced, the flow rate control valve arranged upstream of the ejector is throttled. This lowers the injection nozzle upstream pressure P of the ejector and lowers the injection velocity v of the injection nozzle, so that the momentum mv decreases in a quadratic curve, and the flow rate of the driven gas sucked by the exchange of momentum also becomes two. It will decrease in the following curve. Therefore, the ratio of the suction amount of the low-pressure driven gas to the flow rate of the high-pressure driving gas (suction ratio) is significantly reduced, which makes it difficult to perform the partial load operation of the two-fluid cycle gas turbine.

The present invention was created to solve such problems. That is, an object of the present invention is to keep the suction ratio substantially constant even when the flow rate of the high-pressure drive gas is reduced, thereby sucking the low-pressure driven gas that is approximately proportional to the decrease in the flow rate of the high-pressure drive gas. A variable flow ejector is provided.

[0008]

According to the present invention, a venturi pipe having a throat portion communicating with a low pressure gas, a jet nozzle for jetting high pressure gas in the axial direction of the venturi pipe, and an opening area of the jet nozzle are provided. A variable flow rate ejector is provided, which comprises:

According to a preferred embodiment of the present invention, the injection nozzle is a circular nozzle, and the flow control device has a conical portion axially movably inserted into the circular nozzle and facing the circular nozzle. It consists of a cylindrical adjusting rod and a drive device that moves the adjusting rod in the axial direction. Further, the low-pressure gas is higher in temperature than the high-pressure gas that is saturated steam, so that after mixing both gases, the mixing temperature becomes higher than the saturation temperature corresponding to the partial pressure of the steam, and the steam becomes superheated steam. It is preferable. Further, a gas turbine including a compressor that compresses air, a combustor that burns fuel, and a turbine that is driven by combustion gas to drive the compressor, and a saturated steam from combustion exhaust gas provided downstream of the turbine. A heat exchanger for generating a heat exchanger, and an ejector used in a two-fluid cycle gas turbine, comprising: saturated vapor generated in the heat exchanger, and a compressor compressed to a temperature higher than a saturation temperature of the saturated vapor. It is preferable to mix with compressed air.

[0010]

According to the structure of the present invention, the high pressure gas is ejected in the axial direction of the Venturi tube having the throat portion communicating with the low pressure gas, and the opening area of the injection nozzle is changed by the flow rate adjusting device. Therefore, by changing the opening area of the injection nozzle while maintaining the pressure P on the upstream side of the injection nozzle (that is, while maintaining the original pressure), the injection speed v of the high-pressure gas can be maintained.
The momentum mv can be decreased in proportion to the decrease in the flow rate, and the flow rate of the driven gas sucked by exchanging the momentum can also be decreased in proportion. Therefore, the ratio of the suction amount of the low pressure driven gas to the flow rate of the high pressure driving gas (suction ratio) can be kept substantially constant, and the partial load operation of the two-fluid cycle gas turbine becomes easy.

Further, since the opening area of the injection nozzle can be directly changed by the flow rate adjusting device, the valve (flow rate adjusting valve) conventionally installed on the upstream side can be omitted.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A preferred embodiment of the present invention will be described below with reference to the drawings. The same reference numerals are used for the common parts in each drawing. FIG. 1 is an overall configuration diagram of a two-fluid cycle gas turbine using a variable flow ejector 16 according to the present invention. In this figure, the two-fluid cycle gas turbine 10 is composed of a gas turbine 14, a heat exchanger 15, a variable flow rate ejector 16, and a mixed gas line 17.

The gas turbine 14 includes a compressor 11 for compressing the air 1, a combustor 12 for burning the fuel 3, and a turbine 13 driven by the combustion gas 4 to drive the compressor 11.
The turbine 13 drives the generator 22 via the speed reducer 21 together with the compressor 11 to generate the required electric power 8. The temperature of the combustion exhaust gas 5 discharged from the turbine 13 is, for example, about 534 ° C. when the temperature of the air 1 is about 15 ° C.

The heat exchanger 15 is composed of a boiler main body 23, an economizer 24, and a steam drum 25 which are provided downstream of the turbine 13. The heat exchanger 15 recovers the exhaust heat of the combustion exhaust gas 5 to generate saturated steam 6. ing. The saturated steam 6 becomes, for example, 22 ata and 218 ° C. Most of the saturated steam 6 is taken out of the two-fluid cycle gas turbine as a delivery steam 6a, and the remaining saturated steam 6b is supplied to the variable flow rate ejector 16 in the embodiment of FIG.

The variable flow rate ejector 16 is an ejector using a saturated steam 6b (for example, 22 ata, 218 ° C.) as a drive source in this drawing, and a part 6b of the saturated steam 6 generated in the heat exchanger 15 and the compressor 11. The compressed air 2 is mixed with a part 2a (for example, a temperature of 365 ° C.). The compressed air 2 mixed by the variable flow rate ejector 16 is compressed to a temperature (for example, 365 ° C.) higher than at least the saturation temperature (for example, 218 ° C.) of the saturated steam 6. Further, the remaining portion 2b of the compressed air 2 compressed by the compressor 11 is directly introduced into the combustor 12 as shown in the figure.

With this configuration, the variable flow rate ejector 16
Causes the saturated steam 6 generated in the heat exchanger 15 and its saturation temperature (for example, 218 ° C.) to be higher than that (for example, 365 ° C.).
Since the compressed air 2 compressed by the compressor 11 is mixed with the compressed air 2, the saturated steam 6 can be heated by the high temperature compressed air 2 into superheated steam, and the steam partial pressure is lowered by the mixing, so the superheated steam The degree of superheat can be further increased.

The mixed gas line 17 is a piping line for guiding the mixed gas 7 mixed by the variable flow rate ejector 16 to the combustor 12, and keeps the temperature of the mixed gas mixed by the variable flow rate ejector 16 sufficiently warm so as not to decrease. Has been done. Therefore, the mixed gas 7 mixed by the variable flow rate ejector 16 is passed through the mixed gas line 17 to the combustor 12 of the gas turbine 14.
By introducing the above, saturated steam can be directly used without using a superheater as in the conventional case, and the output and thermal efficiency of the turbine can be increased without generating steam drain. The thermal efficiency at the generator end in the above-described embodiment is about 36%
Becomes

FIG. 2A is an overall configuration diagram of the variable flow rate ejector 16 shown in FIG. 1, and FIG. 2B is a schematic characteristic diagram thereof. In FIG. 2A, a variable flow rate ejector 16 of the present invention includes a venturi tube 18 having a throat portion 18a communicating with a low pressure gas (that is, compressed air 2),
An injection nozzle 19 for ejecting high-pressure gas (that is, saturated vapor 6) in the axial direction of the Venturi tube 18, and an injection nozzle 19
And a flow rate control device 20 for changing the opening area of the.

In the embodiment of FIG. 2, the injection nozzle 19 is a circular nozzle. Further, the flow rate control device 20 includes the circular nozzle 19
A cylindrical adjusting rod 20a, which is movably inserted in the axial direction, has a conical portion facing the circular nozzle, and a drive device 20b which moves the adjusting rod 20a in the axial direction. The drive device 20b may use a linear actuator, such as a hydraulic cylinder, an air cylinder, a linear solenoid, or the like. Further, it is preferable to detect the pressure of the delivered steam 6a and adjust the drive device 20b according to this pressure.

That is, the chamber 18b in which the injection nozzle 19 is disposed is divided into two parts, one of which is a driving fluid chamber and the other is a driven fluid chamber, and both chambers are connected by the injection nozzle 19. are doing. The injection nozzle 19 has a structure in which the nozzle opening area can be changed by the adjusting rod 20a.

With this configuration, the pressure P on the upstream side of the nozzle is
By changing the opening area of the nozzle while maintaining (i.e., the original pressure), the injection speed v of the high-pressure gas can be maintained, and the momentum mv can be decreased in proportion to the decrease in the flow rate. As shown in FIG. 2B, the flow rate of the driven gas sucked by exchanging the momentum can be proportionally reduced. Therefore, the ratio of the suction amount of the low pressure driven gas to the flow rate of the high pressure driving gas (suction ratio) can be kept substantially constant, and the partial load operation of the two-fluid cycle gas turbine becomes easy. Further, since the opening area of the nozzle can be directly changed by the flow rate adjusting device, the valve (flow rate adjusting valve) conventionally installed on the upstream side can be omitted.

Although the variable flow rate ejector of the present invention is used in a two-fluid cycle gas turbine, the present invention is not limited to this embodiment.
Needless to say, various changes can be made without departing from the scope of the present invention.

[0023]

As described above, even if the flow rate of the high-pressure driving gas is reduced, the suction ratio can be kept substantially constant,
As a result, the low-pressure driven gas that is almost proportional to the decrease in the flow rate of the high-pressure driving gas can be sucked, and the conventional valve (flow rate control valve) installed on the upstream side can be omitted. .

[Brief description of drawings]

FIG. 1 is an overall configuration diagram of a two-fluid cycle gas turbine using a variable flow rate ejector according to the present invention.

2 is an overall configuration diagram of the variable flow rate ejector 16 shown in FIG. 1 and a characteristic diagram thereof.

FIG. 3 is an overall configuration diagram of a conventional two-fluid cycle gas turbine.

FIG. 4 is a configuration diagram of a conventional ejector.

[Explanation of symbols]

 S Water vapor 1 Air 2 Compressed air (low pressure gas) 3 Fuel 4 Combustion gas 5 Combustion exhaust gas 6 Saturated steam (high pressure gas) 7 Mixed gas 8 Electric power 10 Two-fluid cycle gas turbine 11 Compressor 12 Combustor 13 Turbine 15 Heat exchanger 16 Variable flow rate ejector 17 Mixed gas line 18 Venturi tube 18a Throat part 18b Chamber 19 Injection nozzle 20 Flow rate control device 20a Control rod 20b Drive device 21 Reducer 22 Generator 23 Boiler body 24 Economizer 25 Steam drum 51 Throttle valve 52 Compressor 53 Combustion chamber 54 Water Treatment Device 55 Pump 56 Heat Exchanger 57, 58 Turbine 59 Condenser 60 Ejector

Claims (4)

[Claims] 1. A venturi tube having a throat portion communicating with low-pressure gas, an injection nozzle for ejecting high-pressure gas in the axial direction of the venturi tube, and a flow rate adjusting device for changing the opening area of the injection nozzle. A variable flow rate ejector characterized in that 2. The injection nozzle is a circular nozzle, and the flow rate adjusting device is a cylindrical adjustment rod axially movably inserted into the circular nozzle and having a conical portion facing the circular nozzle; The variable flow ejector according to claim 1, further comprising a drive device that moves the rod in the axial direction. 3. The low-pressure gas has a temperature higher than that of the high-pressure gas which is saturated vapor, whereby the mixing temperature becomes higher than the saturation temperature corresponding to the partial pressure of the vapor after the both gases are mixed,
The variable flow ejector according to claim 1, wherein the steam becomes superheated steam. 4. A gas turbine comprising a compressor for compressing air, a combustor for burning fuel, and a turbine driven by combustion gas to drive the compressor, and a combustion exhaust gas provided downstream of the turbine. And a heat exchanger for generating saturated steam from the heat exchanger, the ejector being used in a two-fluid cycle gas turbine comprising: the saturated steam generated in the heat exchanger and a temperature higher than a saturation temperature of the saturated steam; The variable flow ejector according to claim 3, wherein the variable flow ejector mixes with compressed air compressed by.