JP2002097965A - Cold heat utilizing power generation system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To generate power at high efficiency without causing icing in an LNG carburetor. SOLUTION: After a high-pressure liquid carbon dioxide (d) produced in a liquefied natural gas carburetor is heated by the exhaust gas (e) from an expansion turbine, high temperature and high pressure gaseous carbon dioxide (g) heated in a heater 8 (16) on the upstream side of the expansion turbine is fed to the expansion turbine 4 for power generation.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cold-heat-generating power generation system for generating electricity by using cold of liquefied natural gas.

[0002]

2. Description of the Related Art Conventionally, as shown in FIG. 3, a liquefied natural gas (hereinafter referred to as LNG) a stored in an LNG tank 1 is pressurized to a high pressure by a pump 2 and then discharged to a factory by an LNG vaporizer 3. b to heat and evaporate it, and then introduce it into the expansion turbine 4
Is generated by a generator 5 directly connected to the power supply.

[0003]

However, this method is
It is impossible to directly heat flammable LNG with a combustion gas or the like. In addition, since a heat medium such as chlorofluorocarbon cannot be used, for example, there is a means for heating with hot water, steam, or the like.

The present invention has been made in view of such a conventional problem, and an object of the present invention is to provide a cold heat power generation system capable of generating power with high efficiency without causing freezing in an LNG vaporizer. To provide.

[0005]

In order to achieve the above object, a cold-heat-generating power generation system of the present invention heats high-pressure liquid carbon dioxide produced by a liquefied natural gas vaporizer with exhaust gas from an expansion turbine, and High-temperature and high-pressure carbon dioxide gas heated by a heater in front of the expansion turbine is passed through the expansion turbine to generate power.

Although there are various heat sources for the heater, it is desirable to use the exhaust gas of the gas turbine effectively.

[0007]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows an example in which an independent heating system is adopted as a heating system for carbon dioxide as a working gas. As shown in FIG. 1, a low-pressure carbon dioxide gas c of 6 ata or more is passed through the LNG vaporizer 3 to vaporize LNGa.

On the other hand, the liquefied carbon dioxide gas liquefied by the LNG vaporizer 3 is temporarily stored in the storage tank 6. The liquefied carbon dioxide gas d in the storage tank 6 is pumped up by the pump 2 and pressurized, and then evaporates again in the carbon dioxide gas boiler 7. The temperature of the vaporized high-pressure carbon dioxide gas e is further raised by an independent heater 8 such as having an alternate combustion type heat storage burner.
High temperature and high pressure gas g is introduced into the expansion turbine 4,
The generator 5 is driven to generate electric power.

The carbon dioxide gas f discharged from the expansion turbine 4
Is supplied to the LNG vaporizer 3 while evaporating and vaporizing the liquefied carbon dioxide gas d while passing through the carbon dioxide gas boiler 7.

Note that, in order to be careful when the expansion turbine 4 trips, a pipe line 9 from the carbon dioxide boiler 7 to the independent heater 8 and an LNG vaporizer 3 from the carbon dioxide boiler 7 are provided.
, It is necessary to provide a bypass 11 between the pipelines 10 to prevent the carbon dioxide gas e from being supplied to the expansion turbine 4. In this connection, an emergency heater 13 is installed downstream of the freezing warehouse 12. In the figure, reference numerals 14 and 15 indicate valves, reference numeral i indicates air, and reference numeral j indicates fuel.

According to this method, the output ratio, that is, the power generation output / LNG amount can be increased by increasing the expansion turbine inlet temperature.

Incidentally, the performance of this method is shown in Table 1.
However, the ventilation volume of LNG was set to 50 t / h. In Table 1, TIT is the expansion turbine inlet temperature.

[0014]

[Table 1]

According to Table 1, the higher the pressure ratio, the higher the efficiency, and the expansion turbine inlet temperature does not contribute much to the improvement of the efficiency. However, it is understood that the power generation output ratio increases as the temperature and the pressure increase.

Accordingly, as a heating method of carbon dioxide gas, a method of heating by gas turbine exhaust is preferable. That is, the single system of FIG. 1 has simple equipment and can generate high efficiency power (for example, an efficiency equal to or higher than that of an existing gas turbine combined power generation using vaporized LNG as fuel) can be obtained. In the combined power generation system of FIG. 2, the power generation output ratio can be further increased, and the efficiency can be made higher than before.

That is, as shown in FIG. 2, a low-pressure carbon dioxide gas c of 6 ata or more is passed through the LNG vaporizer 3 and
Ga is vaporized.

On the other hand, the liquefied carbon dioxide gas liquefied by the LNG vaporizer 3 is temporarily stored in the storage tank 6. The liquefied carbon dioxide gas d in the storage tank 6 is pumped up by the pump 2 and pressurized, and then evaporates again in the carbon dioxide gas boiler 7. The temperature of the vaporized high-pressure carbon dioxide gas e is further raised by a carbon dioxide gas heater 16 using a gas turbine exhaust gas h as a heat source, and is introduced into the expansion turbine 4 as a high-temperature high-pressure gas g. Drives to generate power.

Carbon dioxide e discharged from the expansion turbine 4
Is supplied to the LNG vaporizer 3 while evaporating and vaporizing the liquefied carbon dioxide gas d while passing through the carbon dioxide gas boiler 7.

On the other hand, the gas turbine 17 is
8, a combustor 19 and a gas turbine 20. The air compressor 18 and the gas turbine 20 are directly connected to the expansion turbine 4 and the generator 5.

In order to be careful when the expansion turbine 4 trips, a pipe 9 extending from the carbon dioxide boiler 7 to the independent heater 8 and an LNG vaporizer 3 from the carbon dioxide boiler 7 are provided.
, It is necessary to provide a bypass 11 between the pipelines 10 to prevent the carbon dioxide gas e from being supplied to the expansion turbine 4. In this connection, an emergency heater 13 is installed downstream of the freezing warehouse 12. In the figure, reference numerals 14 and 15 indicate valves, reference numeral i indicates air, and reference numeral j indicates fuel.

Incidentally, Table 2 shows the performance of this method.
However, the expansion turbine pressure ratio was set to 7, and the expansion turbine inlet temperature was set to 400 ° C.

[0023]

[Table 2]

In addition, the cooling output when preheating the carbon dioxide supplied to the carbon dioxide boiler can be used as a cooling source for a cooling or freezing warehouse, and a cogeneration system can be used. It will demonstrate to a high degree.

[0025]

As described above, according to the present invention, it is possible to realize high-efficiency power generation without causing freezing of carbon dioxide gas as a working gas (generation of dry ice).

[Brief description of the drawings]

FIG. 1 is a schematic diagram of a cold heat power generation system according to the present invention.

FIG. 2 is a schematic diagram showing another example of the cold-heat-generating power generation system according to the present invention.

FIG. 3 is a schematic diagram of a conventional cold heat power generation system.

[Explanation of symbols]

 4 Expansion turbine 8, 16 Heater before expansion turbine d High-pressure liquid carbon dioxide produced by liquefied natural gas vaporizer e Exhaust of expansion turbine g High-temperature high-pressure carbon dioxide

Claims (2)

[Claims] After heating a high-pressure liquid carbon dioxide gas produced by a liquefied natural gas vaporizer by exhaust gas from an expansion turbine, a high-temperature high-pressure carbon dioxide gas heated by a heater in front of the expansion turbine is passed through the expansion turbine. Power generation system using cold energy to generate electricity. 2. The cold heat power generation system according to claim 1, wherein exhaust gas of a gas turbine is used as a heat source of the heater.