JPH09151707A - Cryogenic power generating device using liquid natural gas - Google Patents

Abstract

PROBLEM TO BE SOLVED: To perform power generation by effectively utilizing hot/cold heat of liquefied natural gas. SOLUTION: In liquefied natural gas of low temperature, natural gas circulated is condensed in an LNG condenser 12, a mixed fluorocarbon refrigerant is condensed in a fluorocarbon condenser 14, circulating natural gas coming out from an LNG low pressure side expansion turbine 22 is cooled by an LNG heater 16. Natural gas vaporized in an LNG carburetor 18 is further heated by an LNG overheater 19, so as to drive an LNG high pressure side expansion turbine 20. Partly the natural gas coming out from the LNG high pressure side expansion turbine 20 is circulated. The residual, part is burned in a gas turbine 29. A steam turbine cycle evaporating water by utilizing exhaust heat of the gas turbine 29 is driven. Condensed heat of this cycle is heat exchanged as evaporation heat of a Rarnkine cycle with natural gas and mixed fluorocarbon serving as an operating medium, improvement of efficiency can be attained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cold heat power generator using liquefied natural gas for generating electric power by using cold energy of cold heat of liquefied natural gas.

[0002]

2. Description of the Related Art Conventionally, liquefied natural gas (abbreviated as "LN
G) has been proposed as a technology for effectively utilizing the cold heat of G ”). The applicant of the present application also discloses, for example, JP-A-5-1.
13108 (Japanese Patent Application No. 3-275714) discloses a configuration in which power generation using a combined cycle and cold power generation using an LNG Rankine cycle are combined.
2504 (Japanese Patent Application No. 4-108077) discloses a configuration of a circulation direct expansion system in which natural gas vaporized in 2504 (Japanese Patent Application No. 4-108077) is guided to a multistage expansion turbine and a part of natural gas discharged from the expansion turbine is circulated so as to be returned to liquefied natural gas. doing.

FIG. 7 shows a basic structure for generating power using the cold heat of LNG. FIG. 7A shows a single refrigerant system,
FIG. 7B shows the mixed refrigerant system. LNG is L
It is pressurized by the NG pump 1 and heat-exchanged with the refrigerant condensed in the refrigerant condenser 2a or 2b to be vaporized, and is heat-exchanged with the seawater in the warmer 3 to be heated and taken out as natural gas. The refrigerant condensed in the refrigerant condensers 2 a and 2 b is pressurized by the refrigerant pump 4, evaporated in the refrigerant evaporator 5 that exchanges heat with seawater, drives the refrigerant turbine 6, and causes the generator 7 to generate electric power.

[0004]

In recent years, the efficiency of LNG thermal power generation has improved, and it has become possible to design at a combustion temperature of 1400 ° C., and the combustion pressure has increased to 30 kg / cm ² G, and L
The power generation output per ton of NG reaches about 7,000 kWh. However, the cold energy due to the cold heat equivalent to about 250 kWh per ton is not effectively recovered, and as a result, the cold heat is discarded from the warmer 3 and the refrigerant evaporator 5 in FIG. 7 to seawater. In the mixed refrigerant system as shown in FIG. 7 (b), for example, when a hydrocarbon mixed refrigerant is used as the refrigerant, the exergy loss in heat exchange between LNG and the refrigerant is smaller than that of other Rankine systems, so that one unit A large recovery power of 45kWh per LNG ton can be expected from the turbine. However, in this system, since ethane is required as the refrigerant, LNG fractionation equipment is required, and the circulation amount is large, which is not economically advantageous. Although it is possible to use a freon-based refrigerant instead of the hydrocarbon-based one in terms of safety, the freon-based mixed Rankine cycle alone causes a large amount of exergy loss at low temperatures due to problems with the thermophysical properties of freon. I will end up. Further, since it is necessary to select and use CFCs that do not destroy ozone, it is difficult to use the Rankine cycle alone.

The technique of combining the circulation direct expansion method and the propane rankine or freon single rankine has been established, and is an efficient method capable of recovering both LNG cold heat and pressure energy. Since the amount of propane rankine refrigerant circulation is small, the output becomes small. A Brayton cycle in combination with a gas turbine using nitrogen gas is also conceivable, but the efficiency of the compressor becomes a problem, and the efficiency becomes lower than that of recovering the exhaust heat of the gas turbine by the steam turbine.

It is an object of the present invention to provide a cold heat power generator using liquefied natural gas which can utilize the cold heat of liquefied natural gas with high efficiency even if the combined cycle is introduced and the delivery pressure becomes high. is there.

[0007]

The present invention is directed to a mixed CFC Rankine cycle in which a CFC mixed refrigerant for condensing by utilizing the cold heat of liquefied natural gas is circulated, and a mixed CFC refrigerant vapor provided in the Rankine cycle and driven by a mixed CFC refrigerant vapor. The expansion turbine, the high-pressure side expansion turbine driven by the vaporized high-pressure natural gas, and the circulation path in the middle of returning part of the natural gas discharged from the high-pressure side expansion turbine to liquefied natural gas Low pressure side expansion turbine driven by circulating natural gas, a gas turbine in which the rest of the natural gas discharged from the high pressure side expansion turbine is combusted, and steam that uses the exhaust heat of the gas turbine to evaporate water A turbine Rankine cycle, a steam turbine driven by steam in the Rankine cycle, each expansion turbine and A steam turbine, which includes a power generator driven by a turbine to rotate, and uses the latent heat of condensation of the exhaust steam to evaporate the mixed CFC and liquefied natural gas and warm the vaporized natural gas to room temperature; A liquefied natural gas characterized by comprising a gas heating means for heating the natural gas before being led to the high pressure side expansion turbine heated to room temperature with the residual amount of exhaust heat from the gas turbine used in the Rankine cycle. This is the cold heat power generator used. According to the present invention, the liquefied natural gas chills the mixed Freon Rankine cycle to vaporize it, and then drives the high pressure side expansion turbine to circulate a part of the natural gas discharged from the high pressure side expansion turbine. The expansion method and the mixed Freon Rankine cycle using cold heat can be combined to effectively use the cold heat. The rest of the natural gas discharged from the high pressure side expansion turbine is burned in the gas turbine to evaporate water by the exhaust heat, and the latent heat of condensation is used to evaporate the mixed CFCs and liquefied natural gas and bring the vaporized natural gas to the normal temperature. Can be heated to increase the energy of the natural gas recovered by the high pressure side expansion turbine. Since the natural gas is further heated by utilizing the exhaust heat of the gas turbine used in the steam turbine Rankine cycle, the output of the high pressure side expansion turbine can be further increased.

In the present invention, the mixed CFC refrigerant is H
FC-23 is 40-50 MOL% and HFC-134
a is characterized by having a composition of 60 to 50 MOL%. According to the present invention, since the mixed CFC refrigerant is used by mixing with a CFC solvent that does not destroy ozone, it can be condensed at a low temperature to effectively absorb the cold heat of the liquefied natural gas. HF
With C-23 alone, the pressure increases on the high temperature side, and the design pressure must be increased. However, since HFC-134a is mixed, the critical temperature rises, and it is not necessary to increase the design pressure in use.

The present invention also relates to a high temperature side plate fin type heat exchanger for exchanging heat between the natural gas discharged from the low pressure side expansion turbine of the circulation path and the liquefied natural gas which has absorbed heat from the mixed CFC refrigerant. It further includes a low temperature side plate fin type heat exchanger for exchanging heat between the natural gas discharged from the side plate fin type heat exchanger and the liquefied natural gas before absorbing heat from the mixed CFC refrigerant. According to the present invention, the heat exchanger for condensing the natural gas circulating from the low pressure side expansion turbine is divided into two plate fin type heat exchangers to reduce the temperature difference of the heat end of the heat exchanger. Thus, the circulation amount of the mixed freon solvent can be increased.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows the structure of a cold thermal power generation facility according to an embodiment of the present invention. LN for liquefied natural gas
G is pressurized by the main pump 10 and passes through the line 11 to LN.
It is guided to the G condenser 12. The liquefied natural gas discharged from the LNG condenser 12 passes from the pipe line 13 to the Freon condenser 14,
It is led from the pipe line 15 to the LNG warmer 16. The liquefied natural gas discharged from the LNG warmer 16 is passed through the line 17 to LNG.
The LNG high-pressure side expansion turbine 20 is driven by being guided to the vaporizer 18 and vaporized, and further superheated by the LNG superheater 19. The LNG condenser 12 and the LNG warmer 16 each use a plate fin type heat exchanger. Part of the natural gas discharged from the LNG high pressure side expansion turbine 20 is
Through the LNG low pressure side expansion turbine 22. LN
The natural gas that has left the G low pressure side expansion turbine 22 is guided to the LNG warmer 16 and is cooled by exchanging heat with the liquefied natural gas. The cooled natural gas is fed from the line 23 to the LNG condenser 1
2 and is cooled and condensed by the cold heat of liquefied natural gas. The condensed LNG is sent to the conduit 11 by the LNG circulation pump 24 and mixed with the supplied LNG.

The rest of the natural gas from the LNG high pressure side expansion turbine 20 is led to a combustor 28 via a line 25. In the combustor 28, the gas compressed by the air compressor 27 is mixed and burned to drive the gas turbine 29. The exhaust gas discharged from the gas turbine 29 is discharged from the exhaust heat recovery boiler 30 into the atmosphere via the LNG superheater 19.

In the Freon condenser 14, mixed Freon described later is condensed, pressurized by the Freon pump 31, guided to the expansion valve 33 via the conduit 32, and evaporated in the Freon evaporator 34. The evaporated mixed freon is introduced from the conduit 35 to the freon expansion turbine 36, where it is fed to the freon expansion turbine 36.
Drive. The mixed freon discharged from the freon expansion turbine 36 is guided to the freon condenser 14 through the pipe line 37 and condensed. Freon pump 31, Freon condenser 14, expansion valve 3
3, CFC evaporator 34 and CFC expansion turbine 36
Constitutes a Rankine cycle using mixed freon as a refrigerant.

The exhaust heat recovery boiler 30 evaporates the water supplied by the water pump 38 and drives the steam turbine 39 with steam. The steam emitted from the steam turbine 39 exchanges heat with the CFCs and natural gas evaporated in the CFC evaporator 34 and the LNG vaporizer 10, and gives heat of vaporization to the CFCs and natural gas to condense them. The water pump 38, the exhaust heat recovery boiler 30, the steam turbine 39, and the Freon evaporator 34 constitute a high temperature side Rankine cycle using water as a refrigerant. Since the Rankine cycle is divided into the low temperature side and the high temperature side, it is possible to effectively use the cold heat of the liquefied natural gas and the exhaust heat of the gas turbine 29. A generator 40 is connected to the rotating shafts of the gas turbine 29 and the steam turbine 39. The high pressure side expansion turbine 20, the low pressure side expansion turbine 22, and the Freon expansion turbine 36 are connected to the generator 41 via a gear mechanism. It is also possible to provide a generator for each turbine separately or to have another configuration.

2 and 3 show simulation results of the heat balance on the gas turbine side and the heat balance on the liquefied natural gas side in the configuration of FIG. 1, respectively. Hot gas (HO) from the combustor 28 supplied to the gas turbine 29
The temperature of (T-GAS) is set to about 1300 ° C.
The pressure is about 30 kg / cm ² G. The temperature of the exhaust gas (EX-G1) discharged from the gas turbine 29 is about 600 ° C. and the pressure thereof is 0.50 kg / cm ² G.
Exhaust gas after the exhaust heat is recovered by the exhaust heat recovery boiler 30 (E
The temperature of X-G2) is 130 ° C and its pressure is 0.45 kg.
/ Cm ² G. The temperature of the water (WS) circulating in the Rankine cycle on the high-pressure side is about 40 ° C., and the exhaust heat recovery boiler 3
The pressure of the water (FW) pressurized to 0 by the water pump 38 is about 40 kg / cm ² G. Liquefied natural gas (LNG1) supplied from the outside is approximately -160.
C., and becomes about −130 ° C. after being mixed with liquefied natural gas circulated in the pipeline 11 (LNG3). This is heat-exchanged in the LNG condenser 12 (LNG4), -75 degreeC.
The temperature is raised to about 40 ° C., and heat is exchanged with the Freon in the Freon condenser 14 to raise the temperature to (LNG5) −40 ° C. There is a considerable temperature difference between the natural gas (LNG10) exiting the low-pressure side turbine and the LNG (LNG4) exiting the LNG condenser 12, and by separating them, the temperature difference at the hot end as a plate fin type heat exchanger is reduced. However, it is possible to increase the amount of mixed CFCs circulated. Due to the Freon condenser 14, the Freon (FR5) leaving the Freon expansion turbine 36 is -33.
While being cooled from ℃ to -66 ℃ (FR6), after being pressurized to 15 kg / cm ² G by the chlorofluorocarbon pump 31 (FR1), chlorofluorocarbon at about -65 ℃ is -40 ℃.
Raise the temperature to a certain degree.

FIG. 4 shows the relationship between the mixed refrigerant used in the embodiment of FIG. 1 and the LNG temperature and enthalpy change. LN
G temperature from -130 ° C to about -40 ° C (LNG6),
It can be seen that the temperature difference in the heat exchanger is small.

Here, as described above, the combustion temperature 1300
When the efficiency of the combined cycle when the natural gas supply pressure is lowered and the combustion pressure is changed under the operating conditions of ℃ and combustion pressure of 30 kg / cm ² G, the results shown in the following Table 1 are obtained.

[0017]

[Table 1]

The output is a value for 1 ton of LNG, and the efficiency is 125 per ton of LNG on the basis of the total calorific value.
5Nm ³ , gas calorie 10510kcal / Nm ³
And The efficiency of the rotating machine is 88% for the gas turbine, 85% for the air compressor, 85% for the steam turbine, and the air / natural gas flow ratio is 32. From Table 1, it can be seen that when the combustion pressure is increased, the output increase of the gas turbine exceeds the output decrease of the steam turbine, and the efficiency is improved. Therefore, the vaporization supply pressure of liquefied natural gas should be 35 kg / cm ² G LN in consideration of the pressure loss in the pipes and flow control valves.
It is estimated to be appropriate as the vaporization delivery pressure for G thermal power generation. Further, this value can be said to be a sufficiently high delivery pressure since the delivery pressure of the city gas from the LNG receiving terminal is around 30 kg / cm ² G.

Next, an evaluation related to the steam turbine 39 will be performed. No extraction or reheating is done to simplify the calculations. The vapor pressure and the condensing pressure are changed, and the influence on the output is evaluated. The results are shown in Table 2 below.

[0020]

[Table 2]

Increasing the steam pressure raises the temperature of the flue gas from the viewpoint of heat balance, but the recovery power of the steam turbine 39 tends to increase more than the power of the water pump 38, which is a water supply pump. Considering these points, the steam pressure of the combined cycle that has been operating recently is 70 kg / cm.
^It exceeds ² G. Steam pressure 40kg /
cm ² G, the output of the steam turbine 39 according to the condensate temperature and the total efficiency are set to the combustion pressure of the gas turbine of 15.30.
The results are shown in Table 3 below in the case of kg / cm ² G.

[0022]

[Table 3]

If the condensate temperature is lowered, the overall efficiency naturally rises, but it is necessary to set the conditions in consideration of the vaporization temperature rising heating of LNG and the evaporative heating of the mixed CFC refrigerant.

With respect to the natural gas expansion turbine, the natural gas delivery pressure was compared in two cases of 35 and 18 kg / cm ² G, and the influence on the output was evaluated by changing the vaporization pressure and the heating degree. 88% efficiency of natural gas expansion turbine
And Calculation results for 1 ton of LNG are shown in Tables 4 and 5 below for 35 and 18 kg / cm ² G, respectively. Turbine inlet pressure 60, 70, 80 kg / cm ² G
LNG pump power to
8.6, 1 ton of LNG including circulating pump
It becomes 0.3,11.9kWH.

[0025]

[Table 4]

[0026]

[Table 5]

Also, the pump power required for cold heat generation is
The pump delivery pressures required to deliver 35 and 18 kg / cm ² G of natural gas are 45 and 25 kg / cm ² G, respectively.
The results of trial calculation by subtracting the required power are shown as the self-consumption power in Tables 4 and 5. In both cases, it can be seen that as the inlet pressure of the natural gas turbine is increased, the output can be obtained more than the self-consumption power of the LNG pump. From the pressure resistance of the heat exchanger used, it is considered appropriate that the turbine inlet pressure is around 70 kg / cm ² G. Next, regarding the heating temperature at the turbine inlet, although the recovery power increases as the temperature rises, if the temperature of the exhaust gas that exits the exhaust heat recovery boiler of the combined cycle falls too low, white smoke will be produced from the stack and drainage will occur. To do. Therefore, it is necessary to determine the operating conditions of the entire system so that the exhaust gas temperature becomes 80 ° C or higher.

As a Freon mixed refrigerant Rankine system, the output depends on the composition of the mixed Freon and the evaporation pressure.
Mixed CFCs have an ozone depletion potential of 0, and due to the marketability, vapor pressure and solidification temperature, HFC-23 and HFC-13
4a, and the effect of the mixed composition on the output is evaluated. In addition, the effect of evaporating pressure of CFCs on the turbine is also evaluated. First, the physical properties of HFC-based CFC refrigerants having an ozone destruction coefficient of 0 are shown in Table 6 below.

[0029]

[Table 6]

HFC-23 has a low solidification temperature and is unlikely to freeze even if it is heat-exchanged with LNG. However, when it is used as a single medium, it is heated to the steam of the steam turbine, the temperature rises to near the critical pressure, and the CFC refrigerant is used. The design pressure of the system will have to be increased. Therefore, this problem is solved by using a mixed refrigerant with HFC-134a having a high boiling point. Table 7 below shows HFC-23 and HFC-
The values obtained by calculating the physical properties of the boiling point and the dew point at the saturation pressure, the atmospheric pressure, and the combination composition with 134a and R22 with 100% composition are shown. The outlet pressure of the refrigerant turbine is
Atmospheric pressure or higher is required, and the design temperature of the equipment is 40 ° C.
Before and after. To achieve the same design pressure as R22, which is a CFC refrigerant used in conventional cold heat power generation, MO of HFC-23
A suitable L ratio is 40 to 45%. When mixed freon is used, since the boiling point and the dew point are different, the condensed freon liquid can be used for liquefying the turbine outlet gas, so that the circulation amount can be increased compared to a single medium and the output can be increased.

[0031]

[Table 7]

The following Table 8 shows the relationship between the turbine output and the refrigerant pump power with respect to the condensate temperature of the steam turbine when the HFC-23 composition is changed so that the turbine outlet pressure becomes equal to or higher than the atmospheric pressure. The turbine outlet pressure is determined so that the temperature difference between the LNG and the mixed freon in the heat exchanger is 5 ° C or more. The freon vaporization temperature is the condensate temperature −2 ° C., and the turbine inlet pressure is the saturation pressure of this temperature.

[0033]

[Table 8]

It can be seen from Table 8 that the turbine output is hardly affected by the mixed freon composition. Also, if the condensate temperature is raised, the turbine output will increase, but it is necessary to evaluate the total output including the combined cycle.
In terms of equipment design pressure and turbine output, HFC-2
It is considered that the optimum MOL composition of 3 and HFC-134a is 40% to 45%.

Table 9 below shows the relationship between the combined cycle fuel required for LNG vaporization and the exhaust gas and delivery gas temperatures. From Table 9 showing the relationship between the output evaluation of the entire system and the temperature of the exhaust gas and the delivery gas when the condensate temperature is changed, it can be seen that the condensate temperature of 20 ° C is preferable because the output per kg of fuel becomes large. Although there is a problem that the gas delivery temperature decreases to near 0 ° C due to the relationship with the exhaust gas temperature, the efficiency per total calorific value reaches 53.9%.

[0036]

[Table 9]

By using this embodiment, the cold heat of LNG can be effectively recovered. Whereas the conventional LNG receiving terminal required seawater pumps and pipes for LNG vaporization as well as water intake and drainage facilities, by adopting this system, only seawater for safety can be used. For example, when the annual amount of gas received is 5 million tons, the maximum amount of gas delivered in winter is about 1200 t / h, and the amount of seawater required for vaporization is 40 tons per LNG, so about 4800 tons.
0t / h seawater is required.

FIG. 5 shows an average required power of an annual acceptance scale of 5 million tons and a delivery gas pressure of 10 kg / cm ² G, 4.
The case of 0 kg / cm ² G and 70 kg / cm ² G is shown. Of this, about 2000 kW related to seawater pumps
The power of can be reduced by adopting this embodiment.

Further, in the thermal power plant, if the operation is for 14 hours from 8:00 to 22:00, it is possible to generate electricity of 7 million KW / h by using natural gas of about 1000 t / h as fuel. If the temperature rise of seawater is 10 ℃, it will be 430,000t / h.
Cooling seawater is required, and the seawater pump power is about 1
It will be 8,000 kW. If this embodiment is used, cooling seawater is not necessary, and thus about 5% of 900 KW can be reduced.

FIG. 6 shows a delivery pattern of city gas.
When this embodiment is used, the capacity of the LNG vaporization facility is made to correspond to 14 hours from 8:00 to 22:00 due to the facility operation rate, and the peak time zone uses another type of LNG using the safety seawater facility.
Use a carburetor. At a base of 5 million tons, about 6
00t / h LNG is processed by the system of the present embodiment,
Approximately 40 per LNG 1t / h during times of high power demand
It will be possible to generate 0 kW of electricity and supply 240,000 kW of electricity as a whole. Of this, about 40,000 kW is output by cold heat generation, and the overall system becomes a system with efficiency exceeding 53% on the basis of total calorific value. A heat source for vaporization and power generation of LNG, a seawater facility for cooling and a heat exchange device are not required, and the system is economical in terms of facility.

[0041]

As described above, according to the present invention, the cold heat of liquefied natural gas can be effectively used for the condensation of the Freon refrigerant of the mixed Freon Rankine cycle and the condensation of the circulating natural gas, and the power generation. It can be taken out as an increase in quantity. Since it is not necessary to dissipate cold heat to seawater, the amount of seawater used can be reduced, and in addition to seawater pumps and piping, water intake and drainage facilities can be simplified.

Further, according to the present invention, it is possible to obtain a refrigerant having good low temperature characteristics and not requiring an increase in design pressure, by mixing CFCs of HFC-23 and HFC-134a which do not destroy ozone.

Further, according to the present invention, the condensation of the circulating natural gas leaving the low temperature side expansion turbine with the liquefied natural gas is performed by dividing it into two plate fin type heat exchangers, so that the high temperature side plate fin type heat exchange is performed. It is possible to reduce the temperature difference between the cold end of the heat exchanger and the low temperature side plate fin type heat exchanger, and increase the circulation amount of the mixed CFC refrigerant.

[Brief description of the drawings]

FIG. 1 is a piping system diagram showing a configuration of an embodiment of the present invention.

FIG. 2 is a diagram showing a heat balance on the gas turbine side of FIG.

FIG. 3 is a diagram showing a heat balance on the liquefied natural gas side of FIG. 1.

FIG. 4 is a graph showing characteristics of the mixed CFC refrigerant used in the embodiment of FIG.

FIG. 5 is a graph showing average required power at an LNG base.

FIG. 6 is a graph showing a delivery pattern of city gas.

FIG. 7 is a system diagram showing a basic configuration for generating power by using cold heat of LNG.

[Explanation of symbols]

 10 LNG main pump 12 LNG condenser 14 Freon condenser 16 LNG warmer 18 LNG vaporizer 19 LNG superheater 20 LNG high pressure side expansion turbine 22 LNG low pressure side expansion turbine 24 LNG circulation pump 27 air compressor 28 combustor 29 gas Turbine 30 Exhaust heat recovery boiler 31 Freon pump 34 Freon evaporator 36 Freon expansion turbine 38 Water pump 39 Steam turbine 40,41 Generator

Claims (3)

[Claims] 1. A mixed freon Rankine cycle in which a mixed freon refrigerant that condenses by using the cold heat of liquefied natural gas is circulated, an expansion turbine that is provided in this Rankine cycle, and is driven by mixed freon refrigerant vapor, and vaporized. The high-pressure side expansion turbine driven by high-pressure natural gas, and a part of the natural gas discharged from the high-pressure side expansion turbine are installed in the circulation path on the way to return to liquefied natural gas,
Low pressure side expansion turbine driven by circulating natural gas, gas turbine in which the rest of the natural gas discharged from the high pressure side expansion turbine is combusted, and steam turbine Rankine that uses the exhaust heat of the gas turbine to evaporate water It includes a cycle, a steam turbine driven by steam in this Rankine cycle, and a generator driven by each expansion turbine and gas turbine, and utilizes the latent heat of condensation of exhaust steam to generate a mixture of CFCs and liquefied natural gas. Heat exchange means to evaporate and heat vaporized natural gas to room temperature, and to the high pressure side expansion turbine heated to room temperature with the residual amount of exhaust heat from the gas turbine used in the steam turbine Rankine cycle A cold heat power generator using liquefied natural gas, comprising: a gas heating means for heating the previous natural gas. 2. The mixed CFC refrigerant comprises HFC-23 at 40-50 MOL% and HFC-134a at 60-5.
The cold heat power generator using liquefied natural gas according to claim 1, having a composition of 0 MOL%. 3. A high temperature side plate fin type heat exchanger for exchanging heat between the natural gas discharged from the low pressure side expansion turbine of the circulation path and the liquefied natural gas which has absorbed heat from the mixed CFC refrigerant, and a high temperature side plate fin. The low temperature side plate fin type heat exchanger for exchanging heat between the natural gas emitted from the type heat exchanger and the liquefied natural gas before absorbing heat from the mixed CFC refrigerant, further comprising: Cold heat power generator using the liquefied natural gas of.