JP3716133B2 - Exhaust gas recirculation type gas turbine equipment and combined cycle power generation equipment equipped with the gas turbine equipment - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an exhaust gas recirculation type gas turbine facility and a combined cycle power generation facility including the gas turbine facility.
[0002]
[Prior art]
Conventionally, in a gas turbine used for power generation or the like, combustion air is taken into a compressor after removing dust from the outside through a filter or the like, and is compressed to a predetermined pressure by this compressor and sent to a combustor. It is formed to be. The combustion air is combusted in the combustor and becomes high-temperature and high-pressure gas, which drives the rotor of the gas turbine.
[0003]
The air that has worked in the gas turbine becomes exhaust gas, is discharged from the gas turbine, and is discharged from the chimney to the atmosphere via the exhaust duct. The exhaust gas has a large amount of heat energy, and recently, a combined cycle power generation facility is used to effectively use the exhaust gas. A combined cycle power generation facility called an exhaust heat recovery type exhausts exhaust gas after exchanging heat with the boiler feed water in the exhaust heat recovery boiler, and at this time, the boiler feed water heated by the exhaust gas is supplied to the steam turbine as steam. And used for power generation.
[0004]
Further, in a combined cycle power generation facility called an exhaust reburning type, exhaust gas is used as combustion air for a boiler and then discharged. Steam is similarly generated in this boiler, and this steam is supplied to a steam turbine to be used for power generation.
[0005]
In any case, the exhaust heat is effectively used, and the thermal efficiency of the entire plant can be improved. However, high efficiency is not expected under all operating conditions. For example, when the power load is reduced, the output of the gas turbine is controlled so that the output of the gas turbine is reduced. As a result, the above-described steam for driving the turbine cannot be sufficiently generated, and in this case, the plant efficiency is deteriorated.
[0006]
On the other hand, in a gas turbine facility called an exhaust gas recirculation type to which the present invention belongs, a part of the exhaust gas discharged from the gas turbine is returned to the intake side of the gas turbine and mixed with fresh outside air before being supplied to the compressor. Therefore, the output fluctuation of the gas turbine can be suppressed. For example, according to Japanese Patent Laid-Open No. 64-45924, fluctuations in gas turbine output caused by fluctuations in the gas turbine intake temperature are made constant by mixing the exhaust gas of the gas turbine with the intake air, and the fluctuations It is said that it is possible to operate the equipment efficiently.
[0007]
Further, according to Japanese Patent Laid-Open No. 7-34900, in a combined cycle plant using an exhaust gas recirculation type gas turbine, even in the case of partial load operation, the exhaust gas recirculation amount is controlled in accordance with the operation status. The exhaust gas temperature can be kept sufficiently high, deterioration of plant efficiency is suppressed, and controllability is improved by stabilizing the output of the steam turbine system.
[0008]
[Problems to be solved by the invention]
As described above, the exhaust gas recirculation type gas turbine equipment can be efficiently operated. However, the exhaust gas recirculation type gas turbine, including the above-described known examples, has a specific equipment configuration and equipment arrangement. Is not shown. Taking a gas turbine used in the latest combined cycle power generation facility as an example, the exhaust gas has a temperature of about 600 ° C. at the gas turbine outlet and about 100 ° C. at the exhaust heat recovery boiler outlet of the exhaust heat recovery type combined cycle. Therefore, the temperature difference from the outside air in the natural state is large, and the oxygen concentration contained in the exhaust gas is usually about 13 to 15%, which is different from the oxygen concentration in the outside air in the natural state of 21%.
[0009]
On the other hand, a compressor that supplies combustion air to a gas turbine operates in an unstable manner if there is a local physical state variation in the combustion air that is sucked through the intake duct, particularly when the temperature is unevenly distributed. It becomes a state. Therefore, for stable operation, it is usually necessary to suppress local temperature variations at the compressor inlet to about 2 ° C.
[0010]
However, in the exhaust gas recirculation type gas turbine equipment, the gas turbine exhaust gas and the outside air in a natural state must be mixed and supplied to the compressor as combustion air by mixing two kinds of gases having different pressure, temperature, and composition ratio. Don't be. Generally, the temperature difference between the gas turbine exhaust gas and the outside air is several tens of degrees Celsius when the exhaust gas is led from the exhaust heat recovery boiler outlet, and 500 degrees Celsius or more when it is led from the gas turbine outlet. If only these gases are combined, the temperature distribution becomes extremely non-uniform, which is very dangerous for the operation of the gas turbine.
[0011]
According to Japanese Patent Laid-Open No. 7-34900, when exhaust gas is led from the outlet of the exhaust heat recovery boiler during partial load operation of the exhaust heat recovery type combined cycle, about 20% at 30% load and 30% It is said that about 30% of the exhaust gas is recirculated at the time of load in order to stabilize the output of the exhaust heat recovery boiler and the steam turbine and improve the plant thermal efficiency.
[0012]
The present invention has been made in view of the above, and an object of the present invention is to supply the compressor by mixing exhaust gas and fresh outside air uniformly without increasing the physique of a simple structure and exhaust gas recirculation. Another object of the present invention is to provide this kind of recirculation type gas turbine equipment that can achieve stable operation of an exhaust gas recirculation type gas turbine.
[0013]
[Means for Solving the Problems]
That is, the present invention relates to a compressor that compresses combustion air taken in through a filter, a combustion device that burns air compressed by the compressor together with fuel, and supplies high-temperature and high-pressure gas to a gas turbine, and a gas An exhaust gas recirculation duct that takes out a part of the exhaust gas after driving the turbine and supplies it to the air intake side of the compressor is provided, and a part of the exhaust gas is mixed with fresh outside air to be used again as gas turbine combustion air In the exhaust gas recirculation type gas turbine equipment thus formed, the exhaust gas supply port of the exhaust gas recirculation duct is connected to the upstream side of the filter so as to achieve the intended purpose.
[0014]
The present invention also provides a compressor for compressing combustion air taken in through a filter disposed in an intake duct, and the air compressed by the compressor is combusted together with fuel, so that high-temperature and high-pressure gas is supplied to the gas turbine. A combustion apparatus to be supplied, and an exhaust gas recirculation duct that takes out a part of the exhaust gas after driving the gas turbine and supplies it to the air intake side of the compressor, and mixes a part of the exhaust gas with fresh outside air again. In an exhaust gas recirculation type gas turbine facility configured to be used as gas turbine combustion air, an intake duct housing the filter and the exhaust gas recirculation duct are provided below the floor surface of the gas turbine. In addition, the exhaust gas supply port to the intake duct side of the exhaust gas recirculation duct is connected to the upstream side of the filter.
[0015]
Also, in this case, the filter is formed in a square shape, and one of the four side surfaces of the filter that is perpendicular to the gas turbine shaft is connected to an intake duct that supplies combustion air to the compressor. And a side surface facing the air outflow surface forms an air inflow surface connected to the exhaust gas recirculation duct, and two side surfaces parallel to the gas turbine shaft form a fresh outside air inflow surface. Is formed. In addition, a shaft supported by the duct and a flat plate-like louver fixed to the shaft are provided in the duct on the downstream side of the filter.
[0016]
Further, the louver is formed so as to be movable so that the angle can be changed with respect to the direction of intake air flow around the axis. Further, a plurality of the louvers are arranged side by side along the direction of intake air flow. Further, the louver is formed so as to have a curved shape in which the flow of intake air is a curved flow. In addition, a recirculation exhaust gas flow rate adjusting device for adjusting the flow rate of the recirculation exhaust gas is provided inside the exhaust gas recirculation duct. Further, a movable louver for taking in fresh outside air is provided on a side surface of the exhaust gas recirculation duct.
[0017]
The present invention also includes a compressor that compresses combustion air taken in via a filter chamber, a combustion apparatus that burns air compressed by the compressor together with fuel, and supplies high-temperature and high-pressure gas to a gas turbine; An exhaust gas recirculation duct that takes out part of the exhaust gas after driving the gas turbine and supplies it to the air intake side of the compressor, and mixes a part of the exhaust gas with fresh outside air to re-use gas turbine combustion air In a combined cycle power generation facility equipped with an exhaust gas recirculation type gas turbine facility configured to be used, the intake duct of the gas turbine and the exhaust gas recirculation duct are disposed below the mounting floor surface of the gas turbine. The lower part of the exhaust duct connecting the filter chamber to the exhaust heat recovery boiler of the combined cycle and the gas turbine Place the pace, and the exhaust gas supply port to the intake duct side of the exhaust gas recirculation duct, is obtained so as to connected to the filter chamber.
[0018]
That is, in the exhaust gas recirculation type gas turbine equipment formed in this way, the exhaust gas supply port of the exhaust gas recirculation duct that takes out a part of the exhaust gas and supplies it to the air intake side of the compressor is on the upstream side of the filter. Since the exhaust gas and the fresh outside air are formed so as to be connected to each other, mixing is promoted by the mixed flow action when passing through the filter and supplied to the compressor. In this case, the arrangement of the filter unit and the duct is used. The structure alone is simple, and the size of the equipment is not particularly large. Therefore, the exhaust gas and fresh outside air can be mixed evenly without the need to increase the size of the equipment. In this state, the compressor can be supplied to the compressor, and stable operation of the exhaust gas recirculation type gas turbine can be achieved.
[0019]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described in detail based on the illustrated embodiments. FIG. 1 shows an example of a combined cycle power generation facility equipped with the exhaust gas recirculation type gas turbine facility. 1 is a compressor that compresses combustion air, 2 is a gas turbine body, 8 is a steam turbine, 3 is a generator, 9 is an exhaust heat recovery boiler, and 6 is a chimney.
[0020]
In general, in the gas turbine equipment, in addition to the gas turbine device including the compressor 1, the gas turbine main body 2, and the generator 3, an intake chamber 4 that takes in fresh outside air from the outside, and combustion air is sent from the intake chamber to the compressor. And an exhaust duct 7 that guides exhaust gas discharged from the gas turbine to the chimney 6. In the case of an exhaust heat recovery type combined cycle power generation facility, a steam turbine 8 and an exhaust heat recovery boiler 9 are further installed.
[0021]
This exhaust heat recovery type combined cycle power generation facility has a structure in which the gas turbine exhaust gas discharged from the exhaust heat recovery boiler 9 is guided to the intake chamber 4 by an exhaust gas recirculation duct 10 communicated from the middle of the exhaust duct. Yes. The intake chamber 4 is provided with a filter 11 for removing dust contained in the outside air in order to take in outside air from the surroundings.
[0022]
The embodiment shown in FIG. 1 and FIG. 2 is an example applied to a combined cycle power generation facility using a gas turbine of the type shown in, for example, Japanese Patent Laid-Open No. 4-187830. An intake duct 5 that is installed underneath and guides combustion air from the intake chamber 4 to the compressor 1 passes under a frame on which the gas turbine is placed, and the combustion air enters the compressor 1 from below. Supplied.
[0023]
The intake chamber 4 takes in combustion air from three directions (of course, the filter also enters from three directions). In the present invention, one of them (the upstream side of the air flow) is an intake for recirculation exhaust. It is said. Mixing of fresh fresh air and recirculated exhaust gas taken into the intake chamber 4 is promoted by the action of passing through the filter 11 installed in the intake chamber 4. FIG. 3 and FIG. 4 compare this with the case where the exhaust gas recirculation duct 10 is simply connected in the middle of the intake duct 5.
[0024]
As shown in FIG. 3, when the intake duct 5 is simply connected to the exhaust gas recirculation duct 10, the fresh outside air and the recirculated exhaust gas are sucked into the compressor 1 without being uniformly mixed, and the compressor and The gas turbine becomes unstable and very dangerous. On the other hand, in the embodiment of the present invention shown in FIG. 1 and FIG. 4, passing through the complicated structure of the filter 11 results in a turbulent state of the intake air, and mixing of fresh outside air and recirculated exhaust is performed. Made easy. In addition, since the intake chamber 4 is the most upstream part of the intake air, the distance required for mixing can be made the longest, so that the mixing proceeds and the intake air temperature can be made uniform.
[0025]
Further, by connecting the exhaust gas recirculation duct 10 to the intake chamber 4, a filter for removing dust from the recirculated exhaust is installed in the intake chamber 4 in the same manner as a filter for removing dust from the outside air. It becomes possible.
[0026]
Further, the exhaust gas recirculation duct 10 communicates with the intake chamber 4 under the exhaust heat recovery boiler 9, so that the duct route is simplified, so that the effect of suppressing the pressure loss is expected, and the arrangement space is effectively used. This improves the maintainability of the gas turbine equipment and the exhaust heat recovery boiler 9. Further, when the exhaust gas recirculation duct 10 is installed under the exhaust heat recovery boiler 9, the installation work can be labor-saving and simplified by making the both into an integral structure.
[0027]
FIG. 5 shows an example in which the present invention is applied to a type of equipment that takes air from the side of a gas turbine. Compared to the case of applying to the type of intake from below as shown in FIG. 1 and FIG. 2, the advantage of the arrangement space is reduced, but the mixing effect of the gas turbine exhaust and the outside air can be expected similarly.
[0028]
FIG. 6 shows that the louver 12 is mounted in the intake duct 5 in order to more surely mix fresh outside air and recirculated exhaust gas. Since there are various types of filters 11 installed in the intake chamber 4, a sufficient mixing effect may not always be obtained simply by passing the filter. In such a case, the mixing of fresh outside air and recirculated exhaust can be promoted by attaching a louver 12 in the intake duct 5 and changing the flow of intake air. As shown in FIG. 7, the louvers 12 may be arranged in a line as necessary, or the angle may be periodically changed.
[0029]
Moreover, it is necessary to control the amount of recirculated exhaust gas appropriately according to the plant operating conditions. When the load is high and it is necessary to operate at the rated power, it is desirable to take in the entire intake air from fresh outside air as in a normal gas turbine.
[0030]
FIG. 8 shows a combined cycle power generation facility using the exhaust gas recirculation type gas turbine shown in FIGS. 1 and 5. A movable louver 13 is provided on the side surface of the recirculation duct 10 and fresh fresh air is taken in as necessary. It is something that can be done.
[0031]
FIG. 9 shows a damper (recirculation exhaust gas flow rate adjusting device) 14 provided in the recirculation duct 10, and the amount of exhaust gas recirculation is controlled by adjusting the damper opening. By the action of these louvers and dampers, it is possible to supply an appropriate amount of recirculated exhaust gas according to the load. In the case of 100% load, the damper 14 is completely closed while the louver 13 is fully opened. Thus, it is possible to reduce the pressure loss caused by the intake air and suppress the output decrease of the gas turbine.
[0032]
As described above, in the gas turbine equipment formed as described above, the exhaust gas supply port of the exhaust gas recirculation duct 10 is formed so as to be connected to the upstream side of the filter 11. The fresh outside air is promoted to be mixed by the mixed flow action when passing through the filter 11 and supplied to the compressor 1, so that stable operation of the exhaust gas recirculation type gas turbine can be achieved. Further, the configuration in this case is only the arrangement configuration of the filter 11 part and the recirculation duct 10, and the configuration is simple, and the physique of the equipment is not particularly increased.
[0033]
Further, as one embodiment of the present invention, when the present invention is applied to the lower intake type gas turbine, it is possible to effectively use the arrangement space, suppress the pressure loss of the duct, and improve the efficiency of the installation work.
[0034]
【The invention's effect】
As described above, according to the present invention, the exhaust gas and the fresh outside air can be uniformly mixed and supplied to the compressor without increasing the size of the equipment that has a simple configuration and recirculates the exhaust gas. This kind of recirculation type gas turbine equipment capable of achieving stable operation of the recirculation type gas turbine can be obtained.
[Brief description of the drawings]
FIG. 1 is a side view showing an embodiment of a combined cycle power generation facility equipped with a recirculation type gas turbine facility of the present invention.
FIG. 2 is a plan view showing an embodiment of a combined cycle power generation facility equipped with the recirculation type gas turbine facility of the present invention.
FIG. 3 is a diagram showing a non-uniform mixed state of recirculation exhaust and fresh outside air.
FIG. 4 is a diagram showing a uniform mixed state of recirculation exhaust and fresh outside air.
FIG. 5 is a plan view showing another embodiment of the combined cycle power generation facility equipped with the recirculation type gas turbine facility of the present invention.
FIG. 6 is a view showing a louver attached to an intake duct.
FIG. 7 is a diagram showing the flow of intake air when louvers are arranged.
FIG. 8 is a view showing a louver attached to an exhaust gas recirculation duct.
FIG. 9 is a view showing a damper attached to an exhaust gas recirculation duct.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Compressor, 2 ... Gas turbine main body, 3 ... Generator, 4 ... Intake chamber, 5 ... Intake duct, 6 ... Chimney, 7 ... Exhaust duct, 8 ... Steam turbine, 9 ... Exhaust heat recovery boiler, 10 ... Exhaust gas Recirculation duct, 11 ... filter, 12 ... louver, 13 ... louver, 14 ... damper, 15 ... fresh outside air, 16 ... recirculation exhaust, 17 ... gas turbine intake, 20 ... gas turbine combustion device.

Claims (10)

A compressor for compressing combustion air taken in through a filter, a combustion device for burning the air compressed by the compressor together with fuel, and supplying high-temperature and high-pressure gas to the gas turbine; and exhaust after driving the gas turbine An exhaust gas recirculation duct for extracting a part of the gas and supplying it to the air intake side of the compressor, and a part of the exhaust gas is mixed with fresh outside air and used again as gas turbine combustion air. Exhaust gas recirculation gas turbine equipment
An exhaust gas recirculation type gas turbine facility, wherein an exhaust gas supply port of the exhaust gas recirculation duct is connected to an upstream side of the filter. A compressor that compresses combustion air taken in through a filter disposed in an intake duct, and a combustion device that burns the air compressed by the compressor together with fuel and supplies high-temperature and high-pressure gas to a gas turbine; An exhaust gas recirculation duct that takes out a part of the exhaust gas after driving the gas turbine and supplies it to the air intake side of the compressor, and mixes a part of the exhaust gas with fresh outside air to regenerate the gas turbine combustion air In the exhaust gas recirculation type gas turbine equipment that is formed to be used as
The intake duct housing the filter and the exhaust gas recirculation duct are provided below the mounting floor of the gas turbine, and an exhaust gas supply port to the intake duct side of the exhaust gas recirculation duct is provided upstream of the filter. The exhaust gas recirculation type gas turbine equipment is characterized by being connected to the side. The filter is formed in a square shape, and one of the four side surfaces of the filter perpendicular to the gas turbine shaft forms an air outflow surface connected to an intake duct that supplies combustion air to the compressor. In addition, one side face directly facing the air outflow surface forms an air inflow face connected to the exhaust gas recirculation duct, and two side faces parallel to the gas turbine shaft form an inflow face for fresh outside air. The exhaust gas recirculation type gas turbine equipment according to claim 2, wherein 4. The shaft on the two opposite surfaces forming the duct and a flat plate-like louver fixed to the shaft are provided in the duct on the downstream side of the filter. 5. Exhaust gas recirculation type gas turbine equipment. The exhaust gas recirculation type gas turbine equipment according to claim 4, wherein the louver is formed to be movable so that an angle of the louver can be changed with respect to a direction in which intake air flows around the shaft. The exhaust gas recirculation type gas turbine equipment according to claim 4 or 5, wherein a plurality of the louvers are arranged in parallel along a direction in which the intake air flows. The exhaust gas recirculation type gas turbine equipment according to claim 4, 5 or 6, wherein the louver has a curved surface shape in which the flow of intake air is a curved flow. The exhaust gas recirculation type gas turbine equipment according to any one of claims 1 to 7, wherein a recirculation exhaust gas flow rate adjusting device for adjusting a flow rate of the recirculated exhaust gas is provided inside the exhaust gas recirculation duct. The exhaust gas recirculation type gas turbine equipment according to any one of claims 1 to 7, wherein a movable louver for taking in fresh outside air is provided on a side surface of the exhaust gas recirculation duct. A compressor that compresses combustion air taken in through the filter chamber, a combustion device that combusts the air compressed by the compressor together with fuel, and supplies high-temperature and high-pressure gas to the gas turbine; An exhaust gas recirculation duct that takes out a part of the exhaust gas and supplies it to the air intake side of the compressor, and is formed so that a part of the exhaust gas is mixed with fresh outside air and used again as gas turbine combustion air. In the combined cycle power generation facility equipped with the exhaust gas recirculation type gas turbine facility,
The intake duct of the gas turbine and the exhaust gas recirculation duct are disposed below the mounting floor of the gas turbine, and the filter chamber is connected to the gas turbine and the exhaust heat recovery boiler of the combined cycle power generation facility. An exhaust gas recirculation type gas turbine facility is provided, which is disposed in a lower space of the exhaust duct and is connected to an exhaust gas supply port to the intake duct side of the exhaust gas recirculation duct to the filter chamber. Combined cycle power generation equipment.

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