WO2024018579A1 - Cold heat utilizing gas turbin power generation system - Google Patents

Abstract

A cold heat utilizing gas turbine power generation system 100 is provided with: an air liquefaction and separation device 10, a gas turbine power generator 20, a bottoming cycle 30, a pressurized oxygen supply line 52, and a pressurized nitrogen supply line 54. The air liquefaction and separation device 10 liquefies air Air by cold heat of liquid hydrogen LH2 to manufacture, in addition to a required amount of hydrogen gas H2, liquid oxygen LO2 and liquid nitrogen LN2. The gas turbine power generator 20 performs oxygen-enriched combustion of the hydrogen gas H2 to generate power. The bottoming cycle 30 has a reheat combustor 32 and a nitrogen cycle 40. The pressurized oxygen supply line 52 pressurizes the liquid oxygen LO2 in a liquid state, and supplies the pressurized liquid oxygen LO2 to the gas turbine combustor 24 as pressurized oxygen gas after heating the same with a nitrogen gas cooler 48. The pressurized nitrogen supply line 54 pressurizes the liquid nitrogen LN2 in a liquid state, and supplies the pressurized liquid nitrogen LN2 to an exit side of a nitrogen gas compressor 42 as pressurized nitrogen gas after heating the same with the nitrogen gas cooler 48.

Description

Cold energy gas turbine power generation system

The present invention relates to a gas turbine power generation system that utilizes the cold energy of liquid hydrogen.

In 2018, Graz University of Technology announced the Graz Cycle, which uses hydrogen combustion, as a carbon-neutral thermal power generation method that does not emit carbon dioxide gas, which causes global warming. Additionally, the New Energy and Industrial Technology Development Organization (NEDO) has begun studying a hydrogen-oxygen combustion turbine power generation system based on the Graz cycle (2020-2022).
Hydrogen-oxygen combustion turbine power generation systems are disclosed, for example, in Non-Patent Documents 1-3.

Non-Patent Document 1 performs an exergy analysis of the Graz cycle using the characteristics of hydrogen-oxygen combustion. The Graz cycle is a semi-closed combination of the Brayton cycle and the Rankine cycle, using only water vapor as the working fluid through hydrogen-oxygen combustion.
The combustion exergy loss of a state-of-the-art 1600°C class gas turbine is 26.8%, and the exergy efficiency at the transmission end of a gas turbine combined cycle (GTCC) is 56.5%.
On the other hand, in the Graz cycle, the exergy loss of the combustor with a turbine inlet temperature of 1450°C and combustion pressure of 13.8 MPa is 16.9%, and the exergy efficiency at the transmission end is 61.4%, which is higher than that of a 1600°C class gas turbine. It can be greatly improved.
In addition, liquefied hydrogen has exergy of 116.8 MJ/kg as a calorific value and exergy as cold energy of 13.3 MJ/kg. If this cold energy is used for cryogenic separation of air, the exergy efficiency at the transmission end of the Graz cycle can be further improved by 2.1%.

Non-Patent Document 2 states that the oxygen-hydrogen combustion power generation cycle has a thermal efficiency that is 2-11% higher than that of the air-hydrogen combustion GTCC. However, when oxygen production power is taken into account, the transmission net efficiency decreases by 4-6% compared to the generation net efficiency. Therefore, the transmission net efficiency is likely to be on the same level as air-hydrogen combustion GTCC.
Furthermore, Non-Patent Document 2 assumes oxygen-hydrogen stoichiometric complete combustion, but states that complete combustion is not actually possible at an equivalence ratio of 1.

FIG. 1 is an overall configuration diagram of a hydrogen-oxygen combustion turbine power generation system disclosed in Non-Patent Document 3. In this figure, A is a cryogenic separation oxygen production plant, and B is a hydrogen-oxygen combustion turbine.
Cryogenic separation oxygen production plant A uses two distillation columns (called double columns) with different pressures to lower air to a low temperature, concentrating easily evaporable nitrogen into a gas and hard-to-evaporate oxygen into a liquid. Separates oxygen and nitrogen using the vapor-liquid equilibrium of air. The separated oxygen gas is supplied to the hydrogen-oxygen combustor (hereinafter referred to as combustor) of the hydrogen-oxygen combustion turbine B.
Liquid hydrogen is carried in by a hydrogen transport ship and stored in a liquefied hydrogen tank, and hydrogen gas vaporized in a vaporizer is supplied to a combustor.
The combustor of the hydrogen-oxygen combustion turbine B is supplied with hydrogen gas, oxygen gas, and water. In the combustor, hydrogen is combusted to generate high-temperature steam, which drives a turbine and generates electricity. A portion of the water vapor is extracted from the turbine, compressed by a compressor, and recycled to the combustor. The remaining water vapor leaving the turbine is cooled in a condenser and becomes water (condensed water), part of which is supplied to the combustor by a condensate pump and a feed water pump, and the remainder is discharged to the outside.

The hydrogen-oxygen combustion turbine power generation system described above has the following problems.
(1) Energy loss due to oxygen production plants is large.
Hydrogen-oxygen combustion turbines require 1 mole of oxygen gas for every 2 moles of hydrogen gas for complete combustion. Therefore, in terms of weight ratio, hydrogen:oxygen=1:8 for complete combustion, and a larger amount of oxygen gas is required for stable combustion.
On the other hand, even if air is liquefied and separated by the cold heat of 1 kg of liquefied hydrogen, only about 2 kg of oxygen gas is obtained. For this reason, oxygen production plants require power sources other than cold energy for the most part, resulting in large energy losses.
Furthermore, large amounts of nitrogen gas (by-product nitrogen) generated in oxygen production plants do not contribute to power generation.
Therefore, it has been desired to further increase the power generation efficiency including oxygen production plants.
(2) Unless hydrogen and oxygen are combusted in a stoichiometric ratio, there is a problem in that the system cannot be established because non-condensable gas such as residual oxygen (or residual hydrogen) is mixed in the combustion gas. Furthermore, in reality, complete combustion is not possible at an equivalence ratio of 1.
(3) The turbine is essentially a steam turbine, and the final stage is large in size due to pressure reduction operation for energy recovery. Furthermore, since the steam generated in the hydrogen-oxygen combustor and exiting the turbine needs to be cooled down to water (condensed water), the condenser becomes large and requires a large amount of cooling water. Also, maintenance and management of water treatment is necessary.
For this reason, it has been difficult to install inland where large amounts of cooling water are not available.

The present invention was devised to solve the above-mentioned problems. That is, a first object of the present invention is to provide a cold energy gas turbine power generation system that can completely burn hydrogen and increase power generation efficiency by using the cold energy of liquid hydrogen.
A second object of the present invention is to provide a gas turbine power generation system using cold heat that can be installed inland where a large amount of cooling water is not available.

According to the present invention, an air liquefaction separation device that liquefies air using the cold heat of liquid hydrogen to produce a required amount of hydrogen gas, as well as liquid oxygen and liquid nitrogen;
a gas turbine generator that generates electricity by oxygen-enriching combustion of the hydrogen gas;
a reheating combustor that burns the hydrogen gas with residual oxygen and heats the exhaust gas of the gas turbine generator;
a nitrogen cycle that includes a nitrogen gas cooler that cools low-pressure nitrogen gas by exchanging heat with the liquid oxygen and the liquid nitrogen, and that circulates the nitrogen gas and recovers power generation;
Pressurizing the liquid oxygen produced in the air liquefaction separation device in a liquid state, heating the pressurized liquid oxygen in the nitrogen gas cooler, and supplying pressurized oxygen to the gas turbine generator as pressurized oxygen gas. supply line and
The liquid nitrogen produced by the air liquefaction separation device is pressurized in a liquid state, the pressurized liquid nitrogen is heated by the nitrogen gas cooler, and the pressurized nitrogen gas is additionally supplied to the high-pressure nitrogen gas of the nitrogen cycle. A cold energy gas turbine power generation system is provided having a pressurized nitrogen supply line.

According to the configuration of the present invention, the air is liquefied by the cold heat of liquid hydrogen in the air liquefaction separation device to produce the necessary amount of hydrogen gas, so that energy loss in the air liquefaction separation device can be minimized.

The liquid oxygen produced in the air liquefaction separator along with the hydrogen gas is less than the amount of oxygen required by the gas turbine generator. However, this liquid oxygen is pressurized in a liquid state by a pressurized oxygen supply line, heated by a nitrogen gas cooler, and then supplied to the gas turbine generator as pressurized oxygen gas. As a result, it is possible to reduce the compression power by an amount equivalent to about five times the amount of pressurized oxygen gas out of the amount of air compressed by the gas turbine generator.
Furthermore, in the gas turbine generator, the hydrogen gas produced by the air liquefaction separation device is subjected to oxygen-enriched combustion using compressed air and pressurized oxygen gas, so that the hydrogen gas can be stably and completely combusted with a sufficient amount of oxygen.

In addition, the liquid nitrogen produced by the air liquefaction separation device is pressurized in a liquid state by a pressurized nitrogen supply line, heated by a nitrogen gas cooler, and additionally supplied to the high-pressure nitrogen gas of the nitrogen cycle as pressurized nitrogen gas. Thereby, the compression power in the nitrogen cycle can be reduced, and the amount of power generated by the nitrogen cycle can be increased.

In addition, the reheating combustor burns the hydrogen gas produced by the air liquefaction separation device using residual oxygen to heat the exhaust gas temperature, so this high-temperature exhaust gas can sufficiently heat the high-pressure nitrogen gas in the nitrogen cycle, and the nitrogen Cycle efficiency can be increased.

That is, liquid oxygen produced together with the necessary amount of hydrogen gas in the air liquefaction separation device contributes to reducing the power of the gas turbine generator and oxygen-enriched combustion, and liquid nitrogen contributes to increasing the amount of power generated by the nitrogen cycle.

Therefore, overall, the cold heat of liquid hydrogen can be used to produce oxygen for combustion and increase power generation efficiency.

FIG. 2 is an overall configuration diagram of a hydrogen-oxygen combustion turbine power generation system disclosed in Non-Patent Document 3. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a diagram of a first embodiment of a gas turbine power generation system using cold energy according to the present invention. FIG. 1 is an overall configuration diagram of an air liquefaction separation device. FIG. 1 is an overall configuration diagram of a nitrogen cycle. It is a 2nd embodiment figure of the cold heat utilization gas turbine power generation system by this invention. FIG. 1 is an overall configuration diagram of a carbon dioxide gas cycle.

Hereinafter, embodiments of the present invention will be described in detail based on the accompanying drawings. Note that common parts in each figure are given the same reference numerals, and redundant explanation will be omitted.

The main specifications of the hydrogen-oxygen combustion turbine power generation system under development are as follows.
(1) The fuel is pure hydrogen (H ₂ ) and the oxidizer is pure oxygen (O ₂ ) in a stoichiometric ratio (i.e., H ₂ + 1/2O ₂ → H ₂ O, and the molar ratio is H ₂ :O ₂ =1: 0.5).
(2) Hydrogen gas is supplied in the form of liquefied hydrogen, and the liquefied hydrogen is compressed and then vaporized for use.
(3) Oxygen gas is separated from air using three types of air separation methods: cryogenic air separation method (CAS), pressure swing adsorption method (PSA), and high temperature oxygen separation membrane (OTM). use.
(4) Since oxygen gas purity cannot be increased to 100% in any of the air separation methods, stoichiometric combustion cannot be achieved. Therefore, it is necessary to add oxygen gas, and the compression power of oxygen gas up to the combustor pressure is not reflected in power generation efficiency.
(5) Equipment efficiency when calculating power generation efficiency is compressor efficiency: 89%, gas turbine efficiency: 92%, steam turbine efficiency: 84% to 89%, mechanical efficiency: 99%, generator efficiency: 99. 5%, and liquefied hydrogen compression pump efficiency: 100%.
(6) A combined cycle is adopted in which combustion gas (that is, steam) is expanded by a gas turbine and a steam turbine.
(7) Under the above conditions, the power generation efficiency at turbine inlet temperature/pressure: 1550℃/3.3MPa is 62% when using CAS, 63% when using PSA, and 65% when using OTM. It is estimated that.

Hereinafter, hydrogen gas will be referred to as H2, liquefied hydrogen as LH2, oxygen gas as O2, liquid oxygen as LO2, nitrogen gas as N2, and liquid nitrogen as LN2.

(WET type)
FIG. 2 is a diagram of a first embodiment of a gas turbine power generation system 100 utilizing cold energy according to the present invention. Hereinafter, the system of the first embodiment will be referred to as a WET type.
In this figure, a cold energy gas turbine power generation system 100 includes an air liquefaction separation device 10, a gas turbine generator 20, and a bottoming cycle 30.

The air liquefaction separation device 10 liquefies air Air using the cold heat of liquid hydrogen LH2 to produce liquid oxygen LO2 and liquid nitrogen LN2 along with the required amount of hydrogen gas H2.

The gas turbine generator 20 generates electricity by oxygen-enriching combustion of hydrogen gas H2.
In this example, gas turbine generator 20 includes a gas turbine compressor 22, a gas turbine combustor 24, and a gas turbine 26.

The gas turbine compressor 22 compresses air Air. That is, air as an oxidizer is compressed in the same manner as the existing GTCC (normal pressure air is compressed by the gas turbine compressor 22 at the pressure ratio of the existing GTCC) and sent to the gas turbine combustor 24. In this example, a pressure ratio of 23 for 1600°C class GTCCII is adopted.

The gas turbine combustor 24 performs oxygen-enriched combustion of the hydrogen gas H2 vaporized in the air liquefaction separation device 10 using compressed air and pressurized oxygen gas (pressurized oxygen gas O2). That is, in the gas turbine combustor 24, pressurized oxygen gas that has been liquefied and separated from the air is mixed with compressed air and used as oxygen-enriched air. The amount of compressed air will be adjusted so that the residual oxygen concentration after combustion is 16%, which is the same as in the existing LNG combined cycle.

The gas turbine 26 obtains power generation from the combustion gas G1 and drives a generator (not shown) to generate electricity.
In other words, the fuel of the gas turbine generator 20 is hydrogen gas H2, the oxidizing agent is air and oxygen gas O2, and combustion is performed using the same method as the existing GTCC (LNG combined cycle), with the residual oxygen concentration in the exhaust gas being 16% (dry). Burn at the fuel ratio.

The bottoming cycle 30 recovers power generated from the exhaust gas G2 of the gas turbine 26.
In this figure, the bottoming cycle 30 includes a reheating combustor 32, a nitrogen gas turbine cycle (hereinafter referred to as nitrogen cycle 40), and a steam turbine cycle (hereinafter referred to as steam cycle 60).
That is, in this example, a combined cycle with a two-stage bottoming cycle is adopted, in which a nitrogen cycle 40 using the combustion gas of the reheating combustor 32 as a heat source is added between the gas turbine generator 20 and the steam cycle 60.

The reheating combustor 32 burns the hydrogen gas H2 with residual oxygen in the exhaust gas of the gas turbine 26, and heats the exhaust gas G2 of the gas turbine 26. The heating temperature at the entrance of the bottoming cycle 30 is preferably 650 to 700°C.
The amount of hydrogen to be reheated is preferably a small amount (approximately 4% of the amount of hydrogen fuel in the gas turbine generator 20) corresponding to the amount of heating of nitrogen gas N2 in the nitrogen cycle 40.

The nitrogen cycle 40 circulates nitrogen gas N2 and recovers power generation.
In this example, the nitrogen cycle 40 is located immediately downstream of the reheating combustor 32 and includes a nitrogen gas compressor 42, a nitrogen gas heater 44, a nitrogen gas turbine 46, and a nitrogen gas cooler 48.

The nitrogen gas compressor 42 compresses low pressure nitrogen gas (low pressure nitrogen gas N2).
The nitrogen gas heater 44 heats high-pressure nitrogen gas (high-pressure nitrogen gas N2) with high-temperature exhaust gas (high-temperature exhaust gas G2) from the reheating combustor 32.
The nitrogen gas turbine 46 drives a generator (not shown) and recovers power generated from the heated high-pressure nitrogen gas.

The nitrogen gas cooler 48 cools the low-pressure nitrogen gas (intake air cooling) by exchanging heat with liquid oxygen LO2 and liquid nitrogen LN2 supplied from the air liquefaction separation device 10. That is, the nitrogen gas cooler 48 is a heat exchanger that heats the liquid oxygen LO2 and the liquid nitrogen LN2 and cools the low-pressure nitrogen gas.

In FIG. 2, the cold energy gas turbine power generation system 100 further includes a pressurized oxygen supply line 52 and a pressurized nitrogen supply line 54.

The pressurized oxygen supply line 52 has a liquid oxygen pump 52a that pressurizes the liquid oxygen LO2 produced in the air liquefaction separation device 10 in a liquid state, and heats the pressurized liquid oxygen LO2 with the nitrogen gas cooler 48 and pressurizes it. It is supplied to the gas turbine combustor 24 as pressurized oxygen gas.
The pressurizing pressure by the liquid oxygen pump 52a is set to be higher than the internal pressure of the gas turbine combustor 24.
Since the oxygen obtained by the air liquefaction separation device 10 is liquid oxygen LO2, by compressing it in a liquefied state, the pressurizing power up to the combustor inlet pressure is negligibly small.

The pressurized nitrogen supply line 54 has a liquid nitrogen pump 54a that pressurizes the liquid nitrogen LN2 produced by the air liquefaction separation device 10 in a liquid state, and heats the pressurized liquid nitrogen LN2 with the nitrogen gas cooler 48 and pressurizes it. It is supplied to the outlet side of the nitrogen gas compressor 42 as pressurized nitrogen gas.
The pressurizing pressure by the liquid nitrogen pump 54a is set to be higher than the outlet pressure of the nitrogen gas compressor 42.
By compressing the liquid nitrogen LN2 obtained by the air liquefaction separation device 10 in a liquefied state, the power for pressurizing the nitrogen gas to the outlet pressure or higher of the nitrogen gas compressor 42 is negligibly small.

Steam cycle 60 includes a pressure pump 62, a steam heater 64, a steam turbine 66, and a condenser 68.
The pressurizing pump 62 pressurizes the condensed water W1. The steam heater 64 heats the pressurized water W2 with the high-temperature exhaust gas from the nitrogen gas heater 44 to generate high-pressure, high-temperature steam (high-pressure, high-temperature steam S). The steam turbine 66 recovers power generation from the high-pressure, high-temperature steam S.
The condenser 68 cools the low-pressure steam S to obtain condensed water W1.

Note that the nitrogen gas heater 44 and steam heater 64 described above are installed in the exhaust path of the reheating combustor 32, and function as a heat recovery heat exchanger (HRHEX) as a whole.

FIG. 3 is an overall configuration diagram of the air liquefaction separation device 10.
The air is liquefied and separated by pretreatment using the thermal regeneration method (TSA) and heat exchange between LH2 and air. An advantage of this method is that the power consumption is as low as about 1/2 of the conventional cryogenic air separation method.

In FIG. 3, the air liquefaction separation device 10 includes an air compressor 11, a nitrogen gas cooler 12, a helium gas cooler 14, an expansion valve 15, a gas-liquid separator 16, and a gas compressor 17.

The air compressor 11 compresses supply air (air) to a predetermined pressure (for example, 600 kPa).

The nitrogen gas cooler 12 includes a cold heat exchanger 12a and a N2 circulator 12b, and indirectly cools the air by circulating nitrogen gas N2 between the liquid hydrogen LH2 and the air.
The helium gas cooler 14 includes a liquefaction heat exchanger 14a and a He circulator 14b, and indirectly cools the air by circulating helium gas He between the liquid hydrogen LH2 and the air.
The air is cooled to -176° C. by the nitrogen gas cooler 12 and the helium gas cooler 14, for example.

The expansion valve 15 adiabatically expands the cooled air and further cools it to an extremely low temperature (for example, -194° C.).
The gas-liquid separator 16 uses, for example, a double column to separate liquid nitrogen LN2 and liquid oxygen LO2.
The gas compressor 17 compresses the remaining gas and mixes it into the air compressed by the air compressor 11.

With the configuration of the air liquefaction separation device 10 described above, nitrogen and helium are used as intermediate media to liquefy the supply air (air), so direct contact between hydrogen and air can be avoided and safety can be improved.
That is, hydrogen gas H2 is supplied in the form of liquid hydrogen LH2. The liquid hydrogen LH2 is compressed in advance to 5.7 MPa (same as the existing GTCC), and then air is liquefied and separated using the cold heat of vaporization, and then sent to the combustion chamber of the gas turbine combustor 24.

Table 1 shows the material balance in the air liquefaction separation device 10.
As shown in this table, according to the trial calculation results, 3.9 kg/s of liquid nitrogen LN2 and 1.2 kg/s of liquid oxygen LO2 can be liquefied and separated using the cold energy of 1 kg/s of liquid hydrogen LH2.

Table 2 shows the required power of the air liquefaction separation device 10 when using the cold energy of the liquid hydrogen LH2 at 1 kg/s.
From this table, it can be seen that the power of the air compressor 11 that compresses the supply air (air) to a predetermined pressure (for example, 645 kPa) accounts for 95% or more. Additionally, it can be seen that the energy loss is significantly smaller than in conventional air separation devices that liquefy through adiabatic compression and expansion.

FIG. 4 is an overall configuration diagram of the nitrogen cycle 40. The nitrogen cycle 40 has three stages of expansion, and a supercritical nitrogen turbine is used in the high pressure stage.
In this figure, the nitrogen gas heater 44 includes a first gas heater 44a, a second gas heater 44b, and a third gas heater, which are located in order from the upstream side with respect to the high-temperature exhaust gas G2 exiting the reheating combustor 32. It has a container 44c.
Similarly, the nitrogen gas turbine 46 includes a first expander 46a, a second expander 46b, and a third expander 46c, which are located in this order from the upstream side with respect to the high-temperature exhaust gas G2. Nitrogen gas turbine 46 may be a supercritical nitrogen turbine.

Further, in this example, the nitrogen cycle 40 includes a nitrogen gas heat exchanger 49 at the outlet of the first expander 46a, and further includes a nitrogen gas cooler 48 at the subsequent stage (downstream side).
The nitrogen gas heat exchanger 49 preheats the inlet gas of the third gas heater 44c using the outlet gas of the first expander 46a and recovers the heat.
The nitrogen gas cooler 48 cools the compressor inlet gas in order to reduce the compression power of the nitrogen gas compressor 42.

In addition, in this figure, the nitrogen cycle 40 includes a replenishment port 43 for replenishing pressurized nitrogen gas (pressurized nitrogen gas N2) and an extraction port for extracting excess low-pressure nitrogen gas (low-pressure nitrogen gas N2) to the outside. 45.
The refill port 43 is provided between the outlet of the nitrogen gas compressor 42 and the inlet of the nitrogen gas heater 44 (in this example, the inlet of the nitrogen gas heat exchanger 49).
The extraction port 45 is provided between the outlet of the nitrogen gas turbine 46 (in this example, the outlet of the nitrogen gas heat exchanger 49) and the inlet of the nitrogen gas cooler 48.

In this example, in the nitrogen gas heat exchanger 49 of the nitrogen cycle 40, the low temperature (for example, -12°C) nitrogen gas that has joined at the replenishment port 43 and the intermediate temperature (for example, 10°C) nitrogen gas before being discharged from the extraction port 45 are used. Heat exchanges with nitrogen gas.

As described above, the nitrogen gas cooler 48 of the nitrogen cycle 40 precools the refluxing nitrogen gas N2 using the cold heat of vaporization of the liquid nitrogen LN2 and liquid oxygen LO2 that have been air-separated by the air liquefaction separation device 10.
The nitrogen cycle 40 is a regenerative semi-closed gas turbine cycle in which vaporized pressurized nitrogen gas flows into the N2 circulation system of the nitrogen cycle 40 from a replenishment port 43, and the same amount of refluxed N2 is discharged from an extraction port 45. be.

Table 3 shows the main shaft power and power generation output of the nitrogen cycle 40 when the reheating combustor 32 burns hydrogen gas H2 at 0.22 kg/s.
From this table, it can be seen that in the nitrogen cycle 40, the power generation output obtained by multiplying the difference between the expander shaft power and the compressor shaft power by the generator efficiency and the mechanical efficiency is large. That is, expander shaft power/compressor shaft power is approximately 5.7, which is larger than that of a general rotary generator (for example, 2.0 or less in a gas turbine).
In addition, the liquid nitrogen LN2 is pressurized in a liquid state, and the pressurized liquid nitrogen LN2 is heated in the nitrogen gas cooler 48 and is additionally supplied as pressurized nitrogen gas to the high pressure nitrogen gas of the nitrogen cycle 40. As will be described later, high thermal efficiency can be obtained.

Table 4 shows calculation conditions and trial calculation results for the cold energy gas turbine power generation system 100 of the first embodiment (WET type).
The efficiency of each device when calculating power generation performance is: compressor efficiency: 89.5%, gas turbine (GT) efficiency: 91%, steam turbine (ST) efficiency: 90%, mechanical efficiency: 94%, Machine efficiency: 98%, LH2/LO2/LN2 compression pump efficiency: 70%.
In addition, regarding mechanical efficiency, it is necessary to consider losses in the steam condenser cooling water pump, water quality control equipment, lubrication and cooling of various rotating machines, measurement control management equipment, etc. in the actual machine. 94% of them were adopted.

From Table 4, it can be seen that the total power generation output when using liquid hydrogen LH2 of about 5.8 kg/s is about 487 MW, and high power generation efficiency can be obtained.

(DRY type)
FIG. 5 is a diagram of a second embodiment of a gas turbine power generation system 100 utilizing cold energy according to the present invention. Hereinafter, the system of the second embodiment will be referred to as a DRY type.
In this figure, the bottoming cycle 30 has a carbon dioxide cycle 70 instead of the steam cycle 60 on the downstream side of the reheating combustor 32 and the nitrogen cycle 40 described above.

The carbon dioxide cycle 70 circulates carbon dioxide gas and recovers power generation.
In this example, the carbon dioxide cycle 70 includes a carbon dioxide compressor 72, a carbon dioxide heater 74, a carbon dioxide expander 76, and a carbon dioxide cooler 78.
The carbon dioxide compressor 72 compresses carbon dioxide. The carbon dioxide gas heater 74 heats pressurized carbon dioxide gas with the high temperature exhaust gas from the nitrogen gas heater 44 to generate high pressure and high temperature carbon dioxide gas. The carbon dioxide expander 76 drives a generator (not shown) and recovers power generated from the high-pressure, high-temperature carbon dioxide gas. The carbon dioxide cooler 78 cools the carbon dioxide gas at the inlet of the carbon dioxide compressor 72.
For cooling the low-pressure carbon dioxide gas in the carbon dioxide gas cooler 78, it is preferable to use the cooling tower 73, which does not require a large amount of cooling water.

FIG. 6 is an overall configuration diagram of the carbon dioxide cycle 70. The carbon dioxide gas cycle 70 has three stages of expansion, and a supercritical carbon dioxide gas turbine is used in the high pressure stage.
In this figure, the carbon dioxide gas heater 74 includes a first gas heater 74a, a second gas heater 74b, and a third gas heater 74a, which are located in order from the upstream side with respect to the high-temperature exhaust gas G2 that has exited the nitrogen gas heater 44. It has a container 74c.
Similarly, the carbon dioxide expander 76 includes a first expander 76a, a second expander 76b, and a third expander 76c, which are located in order from the upstream side with respect to the high-temperature exhaust gas G2. The carbon dioxide expander 76 is preferably a supercritical carbon dioxide gas turbine.

Further, the carbon dioxide compressor 72 includes a first gas compressor 72a, a second gas compressor 72b, and a third gas compressor 72c located in order from the low pressure side of carbon dioxide gas.
Similarly, the carbon dioxide cooler 78 includes a first cooler 78a, a second cooler 78b, and a third cooler 78c, which are located in order from the low pressure side of carbon dioxide.
That is, a carbon dioxide gas cooler 78 using a cooling tower 73 is provided upstream of the first gas compressor 72a, the second gas compressor 72b, and the third gas compressor 72c, respectively.

Furthermore, in this example, the carbon dioxide cycle 70 includes a carbon dioxide heat exchanger 79 that exchanges heat between the carbon dioxide gas expanded in the first expander 76a and the carbon dioxide gas at the outlet of the third gas compressor 72c.
The other configurations are the same as those in the first embodiment.

Table 5 shows the main shaft power and power generation output of the carbon dioxide cycle 70 when the temperature of the exhaust gas discharged from the nitrogen cycle 40 provided upstream of the carbon dioxide cycle 70 is 603° C. and the amount of exhaust gas is 742 kg/s. .
From this table, it can be seen that in the carbon dioxide cycle 70, the power generation output obtained by multiplying the difference between the expander shaft power and the compressor shaft power by the generator efficiency and mechanical efficiency is large. That is, expander shaft power/compressor shaft power≈2.5, which is larger than a general rotary generator (for example, 2.0 or less in a gas turbine).

Table 6 shows calculation conditions and trial calculation results for the cold energy gas turbine power generation system 100 of the second embodiment (DRY type).
From this table, it can be seen that the total power generation output when using liquid hydrogen LH2 of about 6.2 kg/s is about 487 MW, and high power generation efficiency can be obtained.

The cold heat utilization gas turbine power generation system 100 of the first and second embodiments described above has the following advantages over the hydrogen-oxygen combustion turbine power generation system.

(1) In the hydrogen-oxygen combustion turbine power generation system, it is necessary to produce oxygen gas necessary for combustion of hydrogen gas in an oxygen production plant, and the energy loss caused by the oxygen production plant is large.
On the other hand, in the cold energy gas turbine power generation system 100, only the required amount of hydrogen gas is produced (separated) by the air liquefaction separation device 10 using the cold energy of liquid hydrogen, so the power required for the air liquefaction separation device 10 is reduced. small.

(2) In a hydrogen-oxygen combustion turbine power generation system, the combustion of hydrogen and oxygen (pure oxygen) causes the turbine inlet temperature to become high, so recirculation of steam or water is essential. Therefore, the compressor power increases and the turbine and condenser become larger.
In the cold energy gas turbine power generation system 100, the liquid oxygen LO2 produced in the air liquefaction separation device 10 is pressurized in a liquid state through the pressurized oxygen supply line 52, heated by the nitrogen gas cooler 48, and supplied to the gas turbine as pressurized oxygen gas. It is supplied to the combustor 24.
Therefore, the turbine inlet temperature can be optimized without recirculating steam or water by simply compressing the air corresponding to the oxygen that is insufficient in the gas turbine combustor 24 with the gas turbine compressor 22. And the gas turbine 26 can be downsized.

(3) The hydrogen-oxygen combustion turbine power generation system is a combined cycle of a Brayton cycle and a Rankine cycle, and no other bottoming cycle can be applied upstream of the Rankine cycle.
On the other hand, in the cold energy gas turbine power generation system 100, the bottoming cycle that utilizes the exhaust gas of the gas turbine can be freely set, and in particular, the above-mentioned nitrogen cycle 40 can achieve a power generation efficiency of 97% or more.

(4) As mentioned above, hydrogen-oxygen combustion turbine power generation systems have the disadvantage that unless hydrogen and oxygen are combusted in a stoichiometric ratio, residual oxygen (or residual hydrogen) is mixed in the combustion gas, making it impossible to establish the system. . Furthermore, in reality, complete combustion is not possible at an equivalence ratio of 1.
On the other hand, in the cold heat utilization gas turbine power generation system 100, stable complete combustion can be performed at an air-fuel ratio with a residual oxygen concentration of 16% (dry) in the exhaust gas using the same method as the existing GTCC.

As described above, according to the embodiment of the present invention, the air is liquefied by the cold heat of the liquid hydrogen LH2 in the air liquefaction separation device 10 to produce the necessary amount of hydrogen gas H2, so that the energy loss of the air liquefaction separation device 10 is reduced. can be kept to a minimum.

The liquid oxygen LO2 produced together with the hydrogen gas H2 in the air liquefaction separation device 10 is smaller than the amount of oxygen required by the gas turbine generator 20. However, this liquid oxygen LO2 is pressurized in a liquid state by the pressurized oxygen supply line 52, heated by the nitrogen gas cooler 48, and supplied to the gas turbine generator 20 as pressurized oxygen gas. Thereby, the compression power of the amount of air compressed by the gas turbine generator 20 can be reduced by an amount equivalent to about five times the amount of pressurized oxygen gas.
In addition, in the gas turbine generator 20, the hydrogen gas H2 produced by the air liquefaction separation device 10 is oxygen-enriched and combusted using compressed air and pressurized oxygen gas, so that the hydrogen gas H2 can be stably combusted with a sufficient amount of oxygen. .

In addition, the liquid nitrogen LN2 produced by the air liquefaction separation device 10 is pressurized in a liquid state by the pressurized nitrogen supply line 54, heated by the nitrogen gas cooler 48, and converted into pressurized nitrogen gas to be used as high-pressure nitrogen gas in the nitrogen cycle 40. Additional supply will be provided. Thereby, the compression power in the nitrogen cycle 40 can be reduced, and the amount of power generated by the nitrogen cycle 40 can be increased.

In addition, since the reheating combustor 32 burns the hydrogen gas H2 produced by the air liquefaction separation device 10 using residual oxygen to heat the exhaust gas temperature, the high-pressure nitrogen gas in the nitrogen cycle 40 can be sufficiently heated with this high-temperature exhaust gas. This makes it possible to improve the efficiency of the nitrogen cycle 40.

That is, the liquid oxygen LO2 produced together with the necessary amount of hydrogen gas H2 in the air liquefaction separation device 10 contributes to power reduction and oxygen-enriched combustion of the gas turbine generator 20, and the liquid nitrogen LN2 contributes to the amount of power generated by the nitrogen cycle 40. Contribute to increase.

Further, by having the steam cycle 60 or the carbon dioxide cycle 70 downstream of the nitrogen cycle 40, it is possible to effectively utilize the cold heat of the liquid hydrogen LH2 as a whole to produce oxygen for combustion and increase power generation efficiency.

According to the first embodiment (WET type) of the present invention, power generation efficiency is estimated to be 70.2% (LHV) under the same turbine inlet temperature/pressure conditions as a 1600°C class LNG-fired GTCC, and a hydrogen-oxygen combustion turbine The power generation efficiency is 5.5 to 8 points higher than the approximately 62% to 65% of power generation systems.

Further, the cold heat utilization gas turbine power generation system 100 of the second embodiment (DRY type) does not use a steam turbine, and therefore has the following advantages.
(1) A water treatment system that is difficult to maintain and manage becomes unnecessary.
(2) A large amount of condensing cooling water required for the steam turbine becomes unnecessary.
(3) It is possible to install the power plant inland, where there are few cooling water resources such as seawater, increasing the degree of freedom in installing the power plant.
(4) Although the final stage of the steam turbine becomes larger due to its reduced pressure operation, the nitrogen cycle 40 and carbon dioxide cycle 70 of the first embodiment operate at high pressure and can therefore be made smaller.

Although the power generation efficiency of the second embodiment is 65.6%, which is approximately 4.6% lower than that of the first embodiment, it is still higher than the hydrogen-oxygen combustion turbine power generation system. Therefore, the second embodiment can also be said to be a compact and highly efficient power generation system with a high degree of freedom in installing a power plant.

Note that the present invention is not limited to the embodiments described above, and it goes without saying that various changes can be made without departing from the gist of the present invention.

Air, G1 Combustion gas, G2 Exhaust gas, He Helium gas, H2 Hydrogen gas, LH2 Liquid hydrogen, LO2 Liquid oxygen, LN2 Liquid nitrogen, N2 Nitrogen gas, O2 Oxygen gas, S Water vapor, W1 Condensed water, W2 Pressurized water, 10 Air Liquefaction separation device, 11 air compressor, 12 nitrogen gas cooler, 12a cold heat exchanger, 12b N2 circulator, 14 helium gas cooler, 14a liquefaction heat exchanger, 14b He circulator, 15 expansion valve, 16 gas-liquid separator, 17 gas compressor, 20 gas turbine generator, 22 gas turbine compressor, 24 gas turbine combustor, 26 gas turbine, 30 bottoming cycle, 32 reheating combustor, 40 nitrogen cycle, 42 nitrogen gas compressor, 44 nitrogen gas heater, 44a first gas heater, 44b second gas heater, 44c third gas heater, 46 nitrogen gas turbine, 46a first expander, 46b second expander, 46c third expander, 48 Nitrogen gas cooler, 52 Pressurized oxygen supply line, 52a Liquid oxygen pump, 54 Pressurized nitrogen supply line, 54a Liquid nitrogen pump, 60 Steam cycle, 62 Pressure pump, 64 Steam heater, 66 Steam turbine, 68 Condensate device, 70 carbon dioxide gas cycle, 72 carbon dioxide compressor, 72a first gas compressor, 72b second gas compressor, 72c third gas compressor, 73 cooling tower, 74 carbon dioxide gas heater, 74a first gas heater , 74b second gas heater, 74c third gas heater, 76 carbon dioxide gas expander, 76a first expander, 76b second expander, 76c third expander, 78 carbon dioxide gas cooler, 78a first cooler, 78b Second cooler, 78c Third cooler, 79 Carbon dioxide heat exchanger, 100 Cold heat utilization gas turbine power generation system

Claims (8)

1. an air liquefaction separation device that liquefies air using the cold heat of liquid hydrogen to produce the required amount of hydrogen gas, as well as liquid oxygen and liquid nitrogen;
   a gas turbine generator that generates electricity by oxygen-enriching combustion of the hydrogen gas;
   a reheating combustor that burns the hydrogen gas with residual oxygen and heats the exhaust gas of the gas turbine generator;
   a nitrogen cycle that includes a nitrogen gas cooler that cools low-pressure nitrogen gas by exchanging heat with the liquid oxygen and the liquid nitrogen, and that circulates the nitrogen gas and recovers power generation;
   Pressurizing the liquid oxygen produced in the air liquefaction separation device in a liquid state, heating the pressurized liquid oxygen in the nitrogen gas cooler, and supplying pressurized oxygen to the gas turbine generator as pressurized oxygen gas. supply line and
   The liquid nitrogen produced by the air liquefaction separation device is pressurized in a liquid state, the pressurized liquid nitrogen is heated by the nitrogen gas cooler, and the pressurized nitrogen gas is additionally supplied to the high-pressure nitrogen gas of the nitrogen cycle. A gas turbine power generation system using cold energy, which has a pressurized nitrogen supply line.
2. 1 . The nitrogen cycle further comprises, downstream of the nitrogen cycle, a steam cycle that circulates water vapor and recovers power generation from the exhaust gas, or a carbon dioxide cycle that circulates carbon dioxide and recovers power generation from the exhaust gas. A gas turbine power generation system using cold energy as described in .
3. The air liquefaction separation device includes:
   a nitrogen gas cooler that indirectly cools the air by circulating nitrogen gas between the liquid hydrogen and the air;
   The cold heat gas turbine power generation system according to claim 1, further comprising a helium gas cooler that indirectly cools the air by circulating helium gas between the liquid hydrogen and the air.
4. The nitrogen cycle further includes a nitrogen gas compressor that compresses low-pressure nitrogen gas, a nitrogen gas heater that heats high-pressure nitrogen gas with high-temperature exhaust gas from the reburning combustor, and generates power from the heated high-pressure nitrogen gas. The cold heat utilization gas turbine power generation system according to claim 2, comprising: a nitrogen gas turbine that recovers nitrogen gas.
5. The nitrogen cycle is
   a replenishment port provided between the outlet of the nitrogen gas compressor and the inlet of the nitrogen gas heater and replenishing the pressurized nitrogen gas;
   The cold energy gas turbine power generation system according to claim 4, further comprising an extraction port provided between the outlet of the nitrogen gas turbine and the inlet of the nitrogen gas cooler, and extracting excess low-pressure nitrogen gas to the outside.
6. The carbon dioxide cycle includes a carbon dioxide gas compressor that compresses carbon dioxide gas, and a carbon dioxide gas heater that heats the pressurized carbon dioxide gas with the high temperature exhaust gas of the nitrogen gas heater to generate the high pressure and high temperature carbon dioxide gas. 5. The cold heat gas turbine power generation system according to claim 4, comprising: a carbon dioxide gas expander that recovers power generation from the high-pressure and high-temperature carbon dioxide gas; and a carbon dioxide cooler that cools the low-pressure carbon dioxide gas.
7. The steam cycle includes a pressurizing pump that pressurizes condensed water, a steam heater that heats the pressurized water with high-temperature exhaust gas from the nitrogen gas heater to generate high-pressure, high-temperature steam, and generates power generation from the high-pressure, high-temperature steam. The cold heat gas turbine power generation system according to claim 4, comprising: a steam turbine for recovering water vapor; and a condenser for cooling the low-pressure steam to obtain the condensed water.
8. The gas turbine generator includes a gas turbine compressor that compresses air, a gas turbine combustor that burns the hydrogen gas with oxygen enrichment using compressed air and pressurized oxygen gas, and a gas turbine that generates power using combustion gas. The cold heat utilization gas turbine power generation system according to claim 1, comprising:
   

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