JP2877280B2 - Gas turbine intake cooling system - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to liquefied natural gas (hereinafter referred to as L
The present invention relates to a gas turbine intake cooling device suitable for a gas turbine using a liquefied gas such as NG as a fuel.

[0002]

2. Description of the Related Art Various attempts have been made to improve the output and efficiency by cooling the compressor inlet air of a gas turbine by the cold heat of LNG. 3 shows a first example, FIG. 4 shows a second example, and FIG. 5 shows a third example.

First, in FIG. 3, a compressor (1), a combustor (2), a turbine (3) and a generator (4) are connected to one shaft to form a gas turbine generator. The gas turbine intake at the compressor (1) inlet is cooled by LNG in the heat exchanger (5). That is, in the heat exchanger (5), the intake air is cooled using the cold energy of about 200 kcal / kg of LNG, and the vaporized natural gas (hereinafter referred to as NG) is directly supplied to gas turbine fuel or other fuel.

Next, in the example shown in FIG. 4, the heat exchanger (5) shown in FIG.
This is divided into a heat exchanger for NG vaporization (5b), and both are heat-exchanged using a circulating heat medium. Therefore, the heat medium pump (6) is installed in the circulation system of the circulation heat medium. In this case, as the circulating heat medium, Freon, antifreeze, water or the like is used, and the LNG vaporizing heat exchanger (5) is used.
In (b), latent heat of evaporation is used, and in the heat exchanger (5a) for cooling intake air, sensible heat is used.

Next, an example shown in FIG. 5 is proposed by the inventors of the present invention and applied for a patent. The heat exchanger for LNG vaporization is disposed above the heat exchanger for intake cooling (5a). (5b) is arranged, and both are connected by a heat pipe (7). In this case, the degree of vacuum in the heat pipe (7) is adjusted to an appropriate value by adjusting the degree of vacuum in the heat pipe (7) by an extraction vacuum pump (not shown), thereby preventing icing and frosting of the intake air and appropriately controlling the intake air. Cool to temperature. The heat medium circulates smoothly due to gravity.

There is a method in which cold water is injected into the intake air without using the LNG cold heat to lower the intake temperature of the gas turbine by the sensible heat or the sensible heat and the latent heat of vaporization. .

[0007]

The conventional gas turbine intake air cooling system has the following problems to be solved. 1) In the case of the first example shown in FIG. 3 Since the LNG cold heat source and the gas turbine intake directly exchange heat,
If the heat transfer tube is damaged, there is a risk of blasting LNG.

Further, since LNG itself is at a very low temperature near -200 ° C., moisture in the intake air freezes on the outer surface of the heat transfer tube in contact with the intake air, so that the heat transfer coefficient is significantly reduced. The technology to prevent this icing has not been established at present. Therefore, a plurality of sets of heat exchange modules are provided to perform the switching operation, but the piping and the control system are complicated and the cost increases.

2) In the case of the second example shown in FIG. 4, there is no problem of the LNG blasting or the heat transfer tube freezing, but a plurality of heat exchangers and a circulating medium system are required, the cost is high, and the intake air temperature is high. And the control device for the gas turbine load becomes complicated. In addition, driving power for a circulating medium system Freon compressor or water pump is also required.

3) In the case of the third example shown in FIG. 5, when the gas turbine capacity is large and the air compressor intake temperature is greatly reduced, the gas turbine intake cooling amount or LNG
The amount of heating also increases. In such a case, the heat pipe method cannot provide a large heat flux, so that an extremely large number of heat pipes are required. Therefore, the size of the entire apparatus is increased, construction costs and maintenance costs are increased, and a large space is required.

[0011]

SUMMARY OF THE INVENTION In order to solve the above-mentioned conventional problems, the present invention comprises an evaporative heat transfer tube group disposed in an intake duct of a gas turbine, and a liquid dispersion device and a liquefied gas heat transfer tube therein. A condensing drum communicating with an upper end of the evaporative heat transfer tube group, a lower drum communicating with a lower end of the evaporative heat transfer tube group, a vacuum pump for depressurizing the inside of the condensing drum, and A gas turbine intake cooling device comprising a drum and a circulation pump for pressure-feeding the liquid to the liquid spraying device; and, in addition to the above requirements, gas-liquid separation between the condensing drum and the evaporative heat transfer tube group. It is an object of the present invention to provide an intake cooling device for a gas turbine, wherein a drum is provided, and a condensate reservoir is provided in the condensing drum below the liquefied gas heat transfer tube.

[0012]

In the present invention, since the liquefied gas cold heat source and the gas turbine intake heat exchange heat indirectly via the circulating heat medium such as water and its vapor, there is no danger of liquefied gas blowing. Further, since the heat flux can be increased, the construction cost can be reduced and the space can be reduced.

In the present invention, since the saturation temperature of water or the like can be adjusted by reducing the pressure in the condensing drum with a vacuum pump, it is possible to adjust the temperature of the load of the gas turbine and the temperature of the air introduced into the intake duct. Thus, the intake air of the compressor can be appropriately cooled. Further, by adjusting the temperature of the circulating water or the like as described above, in the evaporative heat transfer tube group, the intake air can be cooled at a temperature that does not freeze,
Ice and frost formation are prevented.

Further, in the present invention, since the latent heat of evaporation of water or the like is used under a vacuum in the condensing drum, the flow rate of water or the like can be remarkably reduced as compared with the conventional system using only sensible heat. In this regard, equipment costs can also be reduced.

When a gas-liquid separation drum is provided in addition to the condensing drum and a condensed liquid reservoir is provided in the condensing drum, the heat transfer area for vapor condensation is kept constant. Cheap.

[0016]

FIG. 1 is a system diagram showing a first embodiment of the present invention. In this figure, a compressor (1), a combustor (2), a turbine (3) and a generator (4) are connected to one shaft to form a gas turbine generator. In the gas turbine intake duct (8) at the inlet of the compressor (1), a steam heat transfer tube group (9) is disposed, and above the steam heat transfer tube group (9).
A condensing drum (10) communicating with the upper end of the lower drum (11) communicating with a lower end of the evaporative heat transfer tube group (9) below.
, Respectively. In the condensing drum (10), an LNG heat transfer tube (12) is provided in the center, and a water sprinkler (13) is provided in the upper part. The upper part of the condensation drum (10) communicates with the suction port of the vacuum pump (14), and the lower part communicates with the suction port of the circulation pump (15). The outlet of the circulation pump (15) communicates with the lower drum (11) and the sprinkler (13).

The condensing drum (1) is driven by a vacuum pump (14).
When the pressure in 0) is reduced to, for example, 0.01 ata, the water in the condensing drum (10) has a water saturation temperature of about 7 ° C. corresponding to 0.01 ata. When the 7 ° C. water flows into the evaporative heat transfer tube group (9) via the lower drum (11) as circulating water by the circulating pump (15), the water is heated by the gas turbine intake and evaporates. 10). This vapor is cooled in the LNG heat transfer tube (12) and condenses.

The LNG heat transfer tube (1) in the condensation drum (10)
In 2), a part is exposed above the liquid surface and a part is immersed below the liquid surface. The heat transfer tubes above the liquid surface contribute to the condensation of steam into water, and the heat transfer tubes below the liquid surface serve to cool the water. Therefore, it is possible to cope with both sensible heat cooling and sensible heat / latent heat cooling.

A part of the circulating water branches off from the inlet of the lower drum (11), is guided to a water spray device (13) provided in the upper part of the condensing drum (10), and is sprayed from a nozzle. This promotes heat transfer from LNG and condensation of steam.

The gas turbine intake air cooled by the evaporative heat transfer tube group (9) flows into the compressor (1). NG vaporized in the LNG heat transfer tube (12) is partially supplied to the combustor (2) as gas turbine fuel, and the other is supplied to a natural gas pipeline or the like.

In this embodiment, since the LNG cold heat source and the gas turbine intake heat exchange indirectly through water and steam, there is no danger of LNG blasting. In addition, compared with the heat pipe method shown in FIG. 5, a circulation pump is required, but the heat flux can be increased. Therefore, when the heat exchange amount between the gas turbine intake and the LNG cold heat is large, the heat pipe method is used. Even lower construction costs and less space will be available.

In the present embodiment, the saturation temperature of water can be adjusted by reducing the pressure inside the condensing drum (10) with a vacuum pump (14). For example, if the pressure is 0.006ata
From 0 to 0.01, the water saturation temperature is about 0 to 7 ° C
It varies in the range up to. Thus the vacuum pump (14)
By adjusting the degree of vacuum in the condensing drum (10), the saturation temperature of water is changed, and compression is performed according to the load of the gas turbine, the temperature of the intake air introduced into the gas turbine intake duct (8), and the like. The intake air guided to the machine can be appropriately cooled. Further, by adjusting the temperature of the circulating water as described above, in the evaporative heat transfer tube group (9), the intake air can be cooled at a temperature that does not freeze, so that icing and frosting can be prevented. .

Further, in this embodiment, the latent heat of evaporation of water is utilized under a vacuum in the condensing drum (10). The latent heat is about 60
0 kcal / kg, sensible heat of water (about 20 kcal /
kg). Therefore, in this embodiment, the flow rate of water is reduced to about 1/3 as compared with the conventional method using the sensible heat of water.
Can be zero.

FIG. 6 is a diagram showing a heat exchange situation between the present embodiment and a conventional system using sensible heat of water. In the present embodiment, since the logarithmic average temperature difference of the evaporative heat transfer tube group (9) can be increased, the heat transfer tubes can be made compact and the pressure loss of the gas turbine intake can be reduced. In this case, the higher the vacuum is set, the more the cooling capacity can be increased. 6, T _A1 and T _A2 are the gas turbine intake temperatures before and after the evaporative heat transfer tube group (9), respectively, and T _c1 and T _c2 are the circulating heat medium (water) before and after the evaporative heat transfer tube group (9), respectively. Temperature. In this embodiment (invention), T _c1 = T _c2 because the latent heat of water is used.

FIG. 2 is a system diagram showing a second embodiment of the present invention. In this figure, the same parts as those in the first embodiment described with reference to FIG. 1 are denoted by the same reference numerals to avoid redundancy, and detailed description is omitted.

In this embodiment, the condensing drum (20)
A steam-water separation drum (21) is provided between the evaporator and the heat transfer tube group (9) below. A condensed water reservoir (23) is provided below the LNG heat transfer tube (22) in the condensing drum (20).
Is provided. Therefore, the steam-water separation drum (2
A dedicated condensation drum (20) is arranged above 1), and the LNG heat transfer tube (22) is dedicated to condensation. That is, the condensed water overflows the condensed water pool (23) and flows down to the steam separator (21). Therefore, between the condensing drum (20) and the steam-water separating drum (21), a flow path (24) for flowing water and ascending steam is provided. A circulating water spraying device (1
Provision of 3) is the same as that of the first embodiment.

In the first embodiment, in order to perform both sensible cooling and latent cooling in the condensing drum (10), the LNG heat transfer tube (12) extends over two phases of gas and liquid. Therefore, with the change or waving of the liquid level at the boundary, the steam condensation performance and the like of the heat transfer tube fluctuate, and it may be difficult to perform heat transfer control. In the second embodiment, a dedicated condensing drum (20) is arranged above the water / water separating drum (21), and condensing and gas / liquid separation are performed by separate drums. Therefore, the LNG heat transfer tube (22) is exclusively used for condensation, and the heat transfer area for vapor condensation is kept constant, so that heat transfer control is easy to perform.

In the above embodiment, water is used as the fluid circulating in the apparatus. However, if the fluid evaporates from a temperature below freezing at a predetermined temperature of about + 15 ° C. and the temperature can be adjusted by adjusting the degree of vacuum, water is used. Other fluids can be used. In the above embodiment, the condensing drums (10), (2)
LNG is introduced into the liquefied gas heat transfer tube in 0) as a cold heat source. Other examples of the cold heat source include a refrigerant for a turbo refrigerator such as ammonia and chlorofluorocarbon, ice, cold water, and the like.
Ice / water slurry can be used. In that case,
As the fuel for the gas turbine, any fuel including NG may be used.

[0029]

In the present invention, since the liquefied gas cold heat source and the gas turbine intake heat exchange indirectly through the circulating heat medium such as water and its vapor, there is no danger of liquefied gas blowing. Also, since the heat flux can be increased, the construction cost can be reduced,
Space can be reduced.

In the present invention, since the saturation temperature of water or the like can be adjusted by reducing the pressure in the condensing drum with a vacuum pump, it is possible to adjust the temperature of the gas turbine load and the temperature of the air introduced into the intake duct. Thus, the intake air of the compressor can be appropriately cooled. Further, by adjusting the temperature of the circulating water or the like as described above, in the evaporative heat transfer tube group, the intake air can be cooled at a temperature that does not freeze,
Ice and frost formation are prevented.

Further, in the present invention, since the latent heat of evaporation of water or the like is used under vacuum in the condensing drum, the flow rate of water or the like can be remarkably reduced as compared with the conventional system using only sensible heat. In this regard, equipment costs can also be reduced.

When a gas-liquid separation drum is provided in addition to the condensing drum, and a condensed liquid reservoir is provided in the condensing drum, the heat transfer area for vapor condensation is kept constant. Cheap.

[Brief description of the drawings]

FIG. 1 is a system diagram showing a first embodiment of the present invention.

FIG. 2 is a system diagram showing a second embodiment of the present invention.

FIG. 3 is a system diagram showing a first example of a conventional device for cooling gas turbine intake air.

FIG. 4 is a system diagram showing a second example of a conventional device for cooling gas turbine intake air.

FIG. 5 is a system diagram showing a third example of a conventional device for cooling gas turbine intake air.

FIG. 6 is a diagram for explaining a heat exchange situation between the present invention and a conventional method.

[Explanation of symbols]

 (1) Compressor (2) Combustor (3) Turbine (4) Generator (5) Heat exchanger (5a) Heat exchanger for intake cooling (5b) Heat exchanger for LNG vaporization (6) Heat medium pump ( 7) Heat pipe (8) Gas turbine intake duct (9) Evaporative heat transfer tube group (10) Condensing drum (11) Lower drum (12) LNG heat transfer tube (13) Sprinkler (14) Vacuum pump (15) Circulation pump ( 20) Condensing drum (21) Steam separation drum (22) LNG heat transfer tube (23) Condensed water reservoir (24) Flow path of flowing down water and rising steam flow

──────────────────────────────────────────────────続 き Continuation of front page (58) Field surveyed (Int.Cl. ⁶ , DB name) F02C 7/143 F02C 3/22 F17C 9/02

Claims (2)

(57) [Claims] An evaporative heat transfer tube group disposed in an intake duct of a gas turbine, a condensing drum having a liquid dispersion device and a liquefied gas heat transfer tube therein and communicating with an upper end of the evaporative heat transfer tube group; A lower drum communicating with a lower end of the heat transfer tube group; a vacuum pump for depressurizing the inside of the condensing drum; and a circulating pump for pressure-feeding the liquid in the condensing drum to the lower drum and the liquid spraying device. Gas turbine intake cooling system. 2. A gas-liquid separation drum is provided between the condensation drum and the evaporative heat transfer tube group, and a condensate reservoir is provided in the condensation drum below the liquefied gas heat transfer tube. The intake cooling device for a gas turbine according to claim 1, wherein