Power generation system using cold and hot type gas turbine

Abstract

A cooling / heating type gas turbine power generation system (100) is provided with an air liquefaction separation device (10), a gas turbine generator (20), a bottom cycle (30), a pressurized oxygen supply line (52), and a pressurized nitrogen supply line (54). An air liquefaction and separation device (10) liquefies air (Air) by cooling and heating liquid hydrogen (LH2), and produces liquid oxygen (LO2) and liquid nitrogen (LN2) together with a necessary amount of hydrogen (H2). The gas turbine generator (20) generates power by oxygen-enriched combustion of hydrogen (H2). The bottom cycle (30) has a re-burning burner (32) and a nitrogen cycle (40). A pressurized oxygen supply line (52) pressurizes liquid oxygen (LO2) in a liquid state, heats the liquid oxygen (LO2) by a nitrogen cooler (48), and supplies the liquid oxygen (LO2) as pressurized oxygen to a gas turbine combustor (24). A pressurized nitrogen supply line (54) pressurizes liquid nitrogen (LN2) in a liquid state, heats the liquid nitrogen (LN2) by a nitrogen cooler (48), and supplies the liquid nitrogen (LN2) as pressurized nitrogen to the outlet side of a nitrogen compressor (42).

Description

Technical Field

[0001] The present invention relates to a gas turbine power generation system utilizing cold and hot liquid hydrogen. Background Art

[0002] In 2018, the 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, which is the main cause of global warming. In addition, the New Energy and Industrial Technology Development Organization (NEDO) has begun research on a hydrogen-oxygen combustion turbine power generation system based on the Graz cycle (2020 to 2022). For example, non-patent documents 1 to 3 disclose hydrogen-oxygen combustion type turbine power generation systems.

[0003] Non-patent document 1 analyzes the exergy of the Gratz cycle using the characteristics of hydrogen-oxygen combustion. The Gratz cycle uses hydrogen-oxygen combustion to make the working fluid only water vapor, thereby forming a combined cycle of the Brayton cycle and the Rankine cycle in a semi-closed manner. The exergy loss of the combustion of the most advanced 1600°C gas turbine is 26.8%, and the exergy efficiency of the gas turbine combined cycle (GTCC) at the transmission end is 56.5%. In contrast, in the Graz cycle, the combustor's effective energy loss at a turbine inlet temperature of 1450°C and a combustion pressure of 13.8 MPa is 16.9%, and the effective energy efficiency at the transmission end is 61.4%, which can be greatly improved compared to a 1600°C class gas turbine. In addition to the calorific value of 116.8 MJ / kg, liquefied hydrogen also has a cold energy of 13.3 MJ / kg. If this cold energy is used for deep cold separation of air, the energy efficiency at the transmission end of the Graz cycle can be further improved by 2.1%.

[0004] Regarding Non-Patent Document 2, the oxygen-hydrogen combustion power generation cycle has a thermal efficiency 2-11% higher than that of the air-hydrogen combustion GTCC. However, if the oxygen production power is taken into account, the transmission-end efficiency is 4-6% lower than the power generation-end efficiency. Therefore, it is highly likely that the transmission-end efficiency will be at the same level as that of the air-hydrogen combustion GTCC. In addition, in Non-Patent Document 2, it is assumed that the combustion is complete under the oxygen-hydrogen stoichiometry, but in reality, the combustion is not complete when the equivalence ratio is 1. Prior Art Literature Non-patent literature

[0005] Non-patent document 1: Seiji Yamashita and three others, "Analysis of the efficiency of hydrogen-oxygen combustion turbines", Journal of the Gas Turbine Society of Japan, 45-3 (2017), pp. 170-177 Non-Patent Document 2: Kotaro Takehana and two others, "Energy Analysis and Performance Analysis of Oxygen-Hydrogen Combustion Power Generation Cycle", Journal of Japan Society of Energy and Resources, Vol. 42, No. 5, (2021) Non-Patent Document 3: "Regarding Oxygen-Hydrogen Combustion Turbine Power Generation System", "Online", "Retrieved on June 20, 2019", Internet,<URL:http: / / www.ghe.iir.titech.ac.jp / japanese / turbine / index.html> Summary of the invention Problems to be solved by the invention

[0006] Figure 1 This is an overall configuration diagram of a hydrogen-oxygen combustion type turbine power generation system disclosed in Non-Patent Document 3. In this figure, A is a cryogenic separation oxygen production facility, and B is a hydrogen-oxygen combustion type turbine. The cryogenic separation oxygen production facility A uses two distillation towers (called double towers) with different pressures to cool the air to concentrate easily evaporated nitrogen in the gas and difficultly evaporated oxygen in the liquid, and separates oxygen from nitrogen by utilizing the gas-liquid equilibrium of the air. The separated oxygen is supplied to the hydrogen-oxygen burner (hereinafter referred to as the burner) of the hydrogen-oxygen combustion turbine B. Liquid hydrogen is transported by a hydrogen transport ship or the like and stored in a liquefied hydrogen tank, and the hydrogen gas vaporized by a vaporizer is supplied to the burner. Hydrogen, oxygen and water are supplied to the burner of the hydrogen-oxygen combustion turbine B. In the burner, high-temperature steam is generated by the combustion of hydrogen, which drives the turbine to generate electricity. A portion of the steam is extracted from the turbine and compressed by the compressor and recirculated to the burner. The remaining steam leaving the turbine is cooled by the condenser and becomes water (condensed water), a portion of which is supplied to the burner through the condensate pump and the water supply pump, and the remaining portion is discharged to the outside.

[0007] The above-mentioned hydrogen-oxygen combustion type turbine power generation system has the following problems. (1) The energy loss of oxygen production equipment is large. In a hydrogen-oxygen combustion turbine, 1 mol of oxygen is required for 2 mol of hydrogen for complete combustion. Therefore, in terms of weight ratio, hydrogen:oxygen=1:8 for complete combustion, and more oxygen is required for stable combustion. On the other hand, even if air is liquefied and separated by cooling and heating 1 kg of liquefied hydrogen, only about 2 kg of oxygen is obtained. Therefore, in most oxygen production facilities, power sources other than cooling and heating are required, and this energy loss is large. In addition, the large amount of nitrogen gas (by-product nitrogen) produced by the oxygen production equipment does not contribute to power generation. Therefore, further improvement in the efficiency of power generation including oxygen production equipment is eagerly desired. (2) If hydrogen and oxygen are not burned at a stoichiometric ratio, residual oxygen (or residual hydrogen) and non-condensable gas will be mixed in the combustion gas, which will make the system inoperable. In addition, 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-scaled for decompression in order to recover energy. In addition, the steam generated by the oxyhydrogen burner and leaving the turbine needs to be cooled to water (condensed water), so the condenser becomes large-scale, requiring a large amount of cooling water used here. In addition, water treatment maintenance management is required. Therefore, inland installation without access to large amounts of cooling water is difficult.

[0008] The present invention is made to solve the above-mentioned problems. That is, a first object of the present invention is to provide a cold-heat type gas turbine power generation system that can perform complete combustion of hydrogen and can improve power generation efficiency by utilizing cold heat of liquid hydrogen. Furthermore, a second object of the present invention is to provide a cold-heat type gas turbine power generation system that can be installed in an inland area where a large amount of cooling water is not available. Solutions to Solve Problems

[0009] According to the present invention, a power generation system utilizing a cold-heat type gas turbine is provided, which comprises: An air liquefaction separation plant, which liquefies air by the cold and heat of liquid hydrogen, and produces liquid oxygen and liquid nitrogen together with the necessary amount of hydrogen; A gas turbine generator that generates electricity by subjecting the hydrogen to oxygen-rich combustion; a reburner for burning the hydrogen gas using the remaining oxygen to heat the exhaust gas of the gas turbine generator; A nitrogen cycle having a nitrogen cooler for cooling low-pressure nitrogen by exchanging heat between the liquid oxygen and the liquid nitrogen, so that the nitrogen is circulated to recover power generation power; a pressurized oxygen supply line that pressurizes the liquid oxygen produced by the air liquefaction separation device in a liquid state, heats the pressurized liquid oxygen by the nitrogen cooler, and supplies the pressurized liquid oxygen to the gas turbine generator as pressurized oxygen; and A pressurized nitrogen supply line pressurizes the liquid nitrogen produced by the air liquefaction separation device in a liquid state, heats the pressurized liquid nitrogen by the nitrogen cooler, and supplies it as pressurized nitrogen gas to the high-pressure nitrogen gas in the nitrogen cycle. Effects of the Invention

[0010] According to the configuration of the present invention, in the air liquefaction separation device, air is liquefied by the cold heat of liquid hydrogen to produce a necessary amount of hydrogen, so that the energy loss of the air liquefaction separation device can be suppressed to a minimum.

[0011] The liquid oxygen produced by the air liquefaction separation device together with hydrogen is less than the amount of oxygen required in the gas turbine generator. However, the liquid oxygen is pressurized in a liquid state by the pressurized oxygen supply line, heated by the nitrogen cooler, and supplied to the gas turbine generator as pressurized oxygen. As a result, the compression power of the air compressed by the gas turbine generator can be reduced by an amount equivalent to about 5 times the pressurized oxygen. In addition, in the gas turbine generator, hydrogen produced by the air liquefaction separation device is burned in an oxygen-rich manner using compressed air and pressurized oxygen, so that the hydrogen can be stably and completely burned with a sufficient amount of oxygen.

[0012] In addition, the liquid nitrogen produced by the air liquefaction separation device is pressurized in a liquid state by the pressurized nitrogen supply line, heated by the nitrogen cooler, and supplied as pressurized nitrogen gas to the high-pressure nitrogen gas in the nitrogen cycle. This can reduce the compression power in the nitrogen cycle and increase the amount of power generated by the nitrogen cycle.

[0013] In addition, the reburning burner uses residual oxygen to burn hydrogen produced by the air liquefaction separation device to heat the exhaust gas temperature, so that the high-temperature exhaust gas can be used to fully heat the high-pressure nitrogen of the nitrogen cycle, thereby improving the efficiency of the nitrogen cycle.

[0014] That is, liquid oxygen produced together with a necessary amount of hydrogen in the air liquefaction separation device contributes to power reduction and oxygen-rich combustion of the gas turbine generator, and liquid nitrogen contributes to increase in power generation using the nitrogen cycle.

[0015] Therefore, the coldness and heat of liquid hydrogen can be used as a whole to produce oxygen for combustion and improve power generation efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 This is an overall configuration diagram of the hydrogen-oxygen combustion type turbine power generation system disclosed in Non-Patent Document 3. Figure 2This is a diagram of a first embodiment of a cold-heat type gas turbine power generation system according to the present invention. Figure 3 This is the overall structure diagram of the air liquefaction separation device. Figure 4 This is the overall structure diagram of the nitrogen cycle. Figure 5 This is a diagram of a second embodiment of a cold-heat type gas turbine power generation system according to the present invention. Figure 6 This is the overall structure diagram of the carbon dioxide cycle. DETAILED DESCRIPTION

[0017] Hereinafter, embodiments of the present invention will be described in detail based on the accompanying drawings. In addition, the same reference numerals are given to common parts in each figure, and repeated descriptions are omitted.

[0018] The main specifications of the hydrogen-oxygen combustion turbine power generation system under development are as follows. (1) The fuel is pure hydrogen (H2) and the oxidant is pure oxygen (O2), and they are burned in a theoretical stoichiometric ratio (i.e., H2+1 / 2O2→H2O, with a molar ratio of H2:O2=1:0.5). (2) Hydrogen gas is supplied in the form of liquefied hydrogen, which is compressed and then vaporized for use. (3) Regarding oxygen, three air separation methods are conceivable, namely, cryogenic air separation (CAS), pressure swing adsorption (PSA), and high temperature oxygen separation membrane (OTM), and oxygen is separated from air for use. (4) No matter which air separation method is used, the oxygen purity cannot be increased to 100%, and theoretical stoichiometric combustion cannot be performed. Therefore, additional oxygen needs to be added, and the compression power of oxygen to the burner pressure is not reflected in the power generation efficiency. (5) The instrument efficiency for calculating power generation efficiency is set as follows: 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 (ie, water vapor) is expanded in a gas turbine and a steam turbine. (7) Under the above conditions, the power generation efficiency at turbine inlet temperature / pressure: 1550°C / 3.3MPa is estimated to be 62% when CAS is used, 63% when PSA is used, and 65% when OTM is used.

[0019] Hereinafter, hydrogen gas is referred to as H2, liquefied hydrogen is referred to as LH2, oxygen gas is referred to as O2, liquid oxygen is referred to as LO2, nitrogen gas is referred to as N2, and liquid nitrogen is referred to as LN2.

[0020] (Wet) Figure 2 This is a diagram of a first embodiment of a cold-heat type gas turbine power generation system 100 according to the present invention. Hereinafter, the system of the first embodiment will be referred to as a wet type. In the figure, a cold-heat type gas turbine power generation system 100 includes an air liquefaction separation device 10 , a gas turbine generator 20 , and a bottoming cycle 30 .

[0021] The air liquefaction separation device 10 liquefies the air Air by using the cold and heat of the liquid hydrogen LH2 and produces liquid oxygen LO2 and liquid nitrogen LN2 together with the necessary amount of hydrogen H2.

[0022] The gas turbine generator 20 generates electricity by performing oxygen-rich combustion on the hydrogen gas H 2 . In this example, the gas turbine generator 20 has a gas turbine compressor 22 , a gas turbine combustor 24 , and a gas turbine 26 .

[0023] The gas turbine compressor 22 compresses the air Air. That is, the air as the oxidant is compressed in the same way as in the conventional GTCC (normal pressure air is compressed by the gas turbine compressor 22 to the pressure ratio of the conventional GTCC) and sent to the gas turbine combustor 24. In this example, the pressure ratio 23 of the 1600°C class GTCCII is adopted.

[0024] The gas turbine combustor 24 uses compressed air and pressurized oxygen (pressurized oxygen O2) to perform oxygen-enriched combustion on the hydrogen H2 vaporized in the air liquefaction separation device 10. That is, in the gas turbine combustor 24, the pressurized oxygen separated by air liquefaction is mixed with the compressed air and used as oxygen-enriched air. The amount of compressed air is adjusted so that the residual oxygen concentration after combustion becomes 16%, which is equivalent to the existing LNG combined cycle.

[0025] The gas turbine 26 obtains power generation power using the combustion gas G1 and drives a generator (not shown) to generate electricity. That is, the fuel of the gas turbine generator 20 is hydrogen H2, the oxidant is air and oxygen O2, and combustion is performed by the same method as the existing GTCC (LNG combined cycle) at an air-fuel ratio with a residual oxygen concentration of 16% (dry oxygen) in the exhaust gas.

[0026] The bottoming cycle 30 recovers power generation power from the exhaust gas G2 of the gas turbine 26 . In the figure, the bottoming cycle 30 has a reburning combustor 32, a nitrogen turbine cycle (hereinafter, nitrogen cycle 40), and a steam turbine cycle (hereinafter, steam cycle 60). That is, in this example, a combined cycle using a two-stage bottoming cycle is adopted in which a nitrogen cycle 40 using the combustion gas of the reburning burner 32 as a heat source is added between the gas turbine generator 20 and the steam cycle 60 .

[0027] The reburner burner 32 burns hydrogen H2 using the residual oxygen in the exhaust gas of the gas turbine 26, thereby heating the exhaust gas G2 of the gas turbine 26. Preferably, the heating temperature at the inlet of the bottoming cycle 30 is 650 to 700°C. It is preferable that the amount of reburned hydrogen is set to a small amount corresponding to the heating amount of the nitrogen gas N2 in the nitrogen cycle 40 (about 4% of the amount of hydrogen fuel in the gas turbine generator 20).

[0028] The nitrogen cycle 40 circulates nitrogen gas N2 to recover power generation power. In this example, the nitrogen cycle 40 is positioned immediately downstream of the reburning burner 32 , and has a nitrogen compressor 42 , a nitrogen heater 44 , a nitrogen turbine 46 , and a nitrogen cooler 48 .

[0029] The nitrogen compressor 42 compresses low-pressure nitrogen (low-pressure nitrogen N 2 ). The nitrogen heater 44 heats the high-pressure nitrogen gas (high-pressure nitrogen gas N2 ) by using the high-temperature exhaust gas (high-temperature exhaust gas G2 ) of the reburning burner 32 . The nitrogen turbine 46 drives a generator (not shown) to recover electric power generated from the heated high-pressure nitrogen.

[0030] The nitrogen cooler 48 cools the low-pressure nitrogen (intake air cooling) by exchanging heat with the liquid oxygen LO2 and liquid nitrogen LN2 supplied from the air liquefaction separation device 10. That is, the nitrogen cooler 48 is a heat exchanger that heats the liquid oxygen LO2 and liquid nitrogen LN2 and cools the low-pressure nitrogen.

[0031] exist Figure 2 In the embodiment, the cold-heat type gas turbine power generation system 100 further includes a pressurized oxygen supply line 52 and a pressurized nitrogen supply line 54 .

[0032] The pressurized oxygen supply line 52 includes a liquid oxygen pump 52 a that pressurizes the liquid oxygen LO2 produced by the air liquefaction separation device 10 in a liquid state, and heats the pressurized liquid oxygen LO2 by the nitrogen cooler 48 to supply the pressurized liquid oxygen LO2 to the gas turbine combustor 24 as pressurized oxygen. The pressurization pressure by the liquid oxygen pump 52 a is set to be equal to or higher than the internal pressure of the gas turbine combustor 24 . The oxygen obtained by the air liquefaction separation device 10 is liquid oxygen LO2, and therefore, by compressing it in a liquefied state, the pressurizing power required to reach the combustor inlet pressure is so small that it can be ignored.

[0033] The pressurized nitrogen supply line 54 includes a liquid nitrogen pump 54 a that pressurizes the liquid nitrogen LN2 produced by the air liquefaction separation device 10 in a liquid state, and the pressurized liquid nitrogen LN2 is heated by the nitrogen cooler 48 and supplied to the outlet side of the nitrogen compressor 42 as pressurized nitrogen gas. The pressurization pressure by the liquid nitrogen pump 54 a is set to be equal to or higher than the outlet pressure of the nitrogen compressor 42 . By compressing the liquid nitrogen LN2 obtained by the air liquefaction separation device 10 in a liquefied state, the pressurizing power to a pressure equal to or higher than the outlet pressure of the nitrogen compressor 42 is reduced to a negligible level.

[0034] The steam cycle 60 includes a pressure pump 62 , a steam heater 64 , a steam turbine 66 , and a condenser 68 . The pressure pump 62 pressurizes the condensed water W1. The steam heater 64 heats the pressurized water W2 using the high temperature exhaust gas of the nitrogen heater 44 to generate high pressure and high temperature steam (high pressure and high temperature steam S). The steam turbine 66 recovers power generated from the high pressure and high temperature steam S. The condenser 68 cools the low-pressure steam S to obtain condensed water W1.

[0035] Furthermore, the nitrogen heater 44 and the water vapor heater 64 are provided in the exhaust gas passage of the reburning burner 32, and function as a heat recovery heat exchanger (HRHEX) as a whole.

[0036] Figure 3 1 is an overall configuration diagram of the air liquefaction separation device 10 . Air separation is achieved by liquefaction / separation using a pre-treatment method using a heat regeneration method (TSA) and a heat exchange method between LH2 and air. The advantage of this method is that the power consumption is only about half of the conventional cryogenic air separation method.

[0037] exist Figure 3 In the embodiment, the air liquefaction separation device 10 includes an air compressor 11 , a nitrogen cooler 12 , a helium cooler 14 , an expansion valve 15 , a gas-liquid separator 16 , and a gas compressor 17 .

[0038] The air compressor 11 compresses the supply gas (air) to a predetermined pressure (for example, 600 kPa).

[0039] The nitrogen cooler 12 includes a cold-hot heat exchanger 12 a and an N 2 circulation machine 12 b , and circulates the nitrogen N 2 between the liquid hydrogen LH 2 and the air to indirectly cool the air. The helium cooler 14 includes a liquefaction heat exchanger 14 a and a He circulation machine 14 b , and circulates helium He between liquid hydrogen LH 2 and air to indirectly cool the air. The air is cooled to, for example, -176°C by the nitrogen cooler 12 and the helium cooler 14.

[0040] The expansion valve 15 adiabatically expands the cooled air to further cool it to an extremely low temperature (eg, -194° C.). The gas-liquid separator 16 separates the liquid nitrogen LN2 from the liquid oxygen LO2 using, for example, a double column. The gas compressor 17 compresses the remaining gas and mixes it into the air compressed by the air compressor 11 .

[0041] According to the configuration of the air liquefaction separation device 10 described above, nitrogen and helium are used as intermediates in the liquefaction of the supply gas (air), so that direct contact between hydrogen and air can be avoided, thereby improving safety. That is, the hydrogen gas H2 is supplied in the form of liquid hydrogen LH2. The liquid hydrogen LH2 is compressed to 5.7 MPa (same as in the conventional GTCC) in advance, and then separated from air by liquefaction using the cold heat of vaporization and sent to the combustion chamber of the gas turbine combustor 24.

[0042] Table 1 shows the material balance in the air liquefaction separation device 10. As shown in the table, according to the estimation results, 3.9 kg / s of liquid nitrogen LN2 and 1.2 kg / s of liquid oxygen LO2 can be liquefied and separated by utilizing the cold and heat of 1 kg / s of liquid hydrogen LH2.

[0043] [Table 1]

[0044] Table 2 shows the necessary power of the air liquefaction separation device 10 when using 1 kg / s of liquid hydrogen LH2 for cooling and heating. As can be seen from the table, the power of the air compressor 11 for compressing the supply gas (air) to a predetermined pressure (eg, 645 kPa) accounts for more than 95%. In addition, it can be seen that the energy loss is significantly smaller than that of a conventional air separation device that liquefies by adiabatic compression and adiabatic expansion.

[0045] [Table 2] Liquid hydrogen volume: 1.0kg / s

[0046] Figure 4 This is a diagram showing the overall structure of the nitrogen cycle 40. The nitrogen cycle 40 is configured as a three-stage expansion system, and a supercritical nitrogen turbine is used in the high-pressure stage. In the figure, the nitrogen heater 44 includes a first gas heater 44 a , a second gas heater 44 b , and a third gas heater 44 c which are positioned in order from the upstream side with respect to the high-temperature exhaust gas G2 leaving the reburning burner 32 . The nitrogen turbine 46 also includes a first expander 46a, a second expander 46b, and a third expander 46c located in order from the upstream side with respect to the high-temperature exhaust gas G2. Preferably, the nitrogen turbine 46 is a supercritical nitrogen turbine.

[0047] In this example, the nitrogen cycle 40 includes a nitrogen heat exchanger 49 at the outlet of the first expander 46 a and a nitrogen cooler 48 at the subsequent stage (downstream side) thereof. The nitrogen heat exchanger 49 preheats the inlet gas of the third gas heater 44 c using the outlet gas of the first expander 46 a to recover heat. The nitrogen cooler 48 cools the compressor inlet gas in order to reduce the compression power of the nitrogen compressor 42 .

[0048] In addition, in the figure, the nitrogen cycle 40 has a replenishment port 43 for replenishing the pressurized nitrogen gas (pressurized nitrogen gas N2) and an extraction port 45 for extracting the remaining low-pressure nitrogen gas (low-pressure nitrogen gas N2) to the outside. The replenishment port 43 is provided between the outlet of the nitrogen compressor 42 and the inlet of the nitrogen heater 44 (in this example, the inlet of the nitrogen heat exchanger 49 ). The extraction port 45 is provided between the outlet of the nitrogen turbine 46 (in this example, the outlet of the nitrogen heat exchanger 49 ) and the inlet of the nitrogen cooler 48 .

[0049] In this example, in the nitrogen heat exchanger 49 of the nitrogen cycle 40 , heat exchange is performed between the low-temperature (eg, −12° C.) nitrogen gas that merges at the replenishment port 43 and the medium-temperature (eg, 10° C.) nitrogen gas before being discharged from the extraction port 45 .

[0050] As described above, in the nitrogen cooler 48 of the nitrogen cycle 40, the reflux nitrogen N2 is precooled by utilizing the vaporization heat of the liquid nitrogen LN2 and the liquid oxygen LO2 separated from the air by the air liquefaction separation device 10. The nitrogen cycle 40 is a regenerative semi-closed gas turbine cycle in which the vaporized pressurized nitrogen gas is joined to the N 2 circulation system of the nitrogen cycle 40 from the replenishment port 43 and an equal amount of reflux N 2 is discharged from the extraction port 45 .

[0051] Table 3 shows the main shaft power and power generation output of the nitrogen cycle 40 when 0.22 kg / s of hydrogen H 2 is combusted using the reburning burner 32 . As can be seen from the table, 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, the expander shaft power / compressor shaft power ≈ 5.7, which is larger than that of a general rotary generator (for example, 2.0 or less in a gas turbine, etc.). In addition, liquid nitrogen LN2 is pressurized in a liquid state, and the pressurized liquid nitrogen LN2 is heated by the nitrogen cooler 48 and supplied as pressurized nitrogen gas to the high-pressure nitrogen gas in the nitrogen cycle 40. Therefore, as described later, the nitrogen cycle 40 can obtain high thermal efficiency.

[0052] [Table 3] Hydrogen combustion capacity: 0.22kg / s

[0053] Table 4 shows calculation conditions and estimation results in the cold-heat utilizing type gas turbine power generation system 100 of the first embodiment (wet type). In addition, the efficiency of each instrument when calculating the power generation performance is set as follows: compressor efficiency: 89.5%, gas turbine (GT) efficiency: 91%, steam turbine (ST) efficiency: 90%, mechanical efficiency: 94%, generator efficiency: 98%, LH2 / LO2 / LN2 compression pump efficiency: 70%. In addition, regarding mechanical efficiency, in actual equipment, it is necessary to consider the losses of the cooling water pump of the steam condenser, various instruments for water quality management, lubrication / cooling of various rotating machines, and measurement, control and management instruments. In this example, 94% is used, which is the same as the existing GTCC.

[0054] As can be seen from Table 4, the total power generation output when using about 5.8 kg / s of liquid hydrogen LH2 is about 487 MW, and high power generation efficiency can be obtained.

[0055] [Table 4] First Embodiment Inlet air (atmospheric) temperature 4℃ Inlet (atmospheric) pressure 100kPa Intake (atmospheric) flow 682kg / s Fuel (hydrogen) usage 5.8kg / s Gas turbine power output 325MW Nitrogen cycle power output 30MW Steam cycle power generation output 132MW Total power output 487MW Power generation efficiency (LHV, transmission end) 70.2％

[0056] (Dry) Figure 5 This is a diagram of a second embodiment of a cold-heat type gas turbine power generation system 100 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 above-mentioned reburning burner 32 and nitrogen cycle 40.

[0057] The carbon dioxide cycle 70 circulates carbon dioxide to recover power generation. In this example, the carbon dioxide cycle 70 has 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 heater 74 uses the high-temperature exhaust gas of the nitrogen heater 44 to heat the pressurized carbon dioxide to produce high-pressure and high-temperature carbon dioxide. The carbon dioxide expander 76 drives a generator (not shown) to recover power from the high-pressure and high-temperature carbon dioxide. The carbon dioxide cooler 78 cools the carbon dioxide at the inlet of the carbon dioxide compressor 72. It is preferable to use a cooling tower 73 which does not require a large amount of cooling water to cool the low-pressure carbon dioxide in the carbon dioxide cooler 78 .

[0058] Figure 6 1 is an overall configuration diagram of a carbon dioxide cycle 70. The carbon dioxide cycle 70 is configured as a three-stage expansion, and a supercritical carbon dioxide turbine is applied to the high-pressure stage. In the figure, the carbon dioxide heater 74 includes a first gas heater 74 a , a second gas heater 74 b , and a third gas heater 74 c , which are positioned in order from the upstream side with respect to the high-temperature exhaust gas G2 leaving the nitrogen heater 44 . The carbon dioxide expander 76 also includes a first expander 76a, a second expander 76b, and a third expander 76c located in order from the upstream side with respect to the high-temperature exhaust gas G2. Preferably, the carbon dioxide expander 76 is a supercritical carbon dioxide turbine.

[0059] Furthermore, the carbon dioxide compressor 72 includes a first gas compressor 72 a , a second gas compressor 72 b , and a third gas compressor 72 c , which are positioned in order from the low-pressure side of carbon dioxide. In addition, the carbon dioxide cooler 78 also includes a first cooler 78 a , a second cooler 78 b , and a third cooler 78 c , which are positioned in order from the low-pressure side of carbon dioxide. That is, a carbon dioxide cooler 78 using a cooling tower 73 is provided on the upstream side of each of the first gas compressor 72 a , the second gas compressor 72 b , and the third gas compressor 72 c .

[0060] In this example, the carbon dioxide cycle 70 includes a carbon dioxide heat exchanger 79 that performs heat exchange between the carbon dioxide expanded by the first expander 76 a and the carbon dioxide at the outlet of the third gas compressor 72 c . The other configurations are the same as those of the first embodiment.

[0061] Table 5 shows the main shaft power and power generation output of the carbon dioxide cycle 70 when the exhaust gas temperature exhausted from the nitrogen cycle 40 provided upstream of the carbon dioxide cycle 70 is 603° C. and the exhaust gas amount is 742 kg / s. As can be seen from the table, 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 the mechanical efficiency is large. That is, the expander shaft power / compressor shaft power ≈ 2.5, which is larger than that of a general rotary generator (for example, in a gas turbine, etc., 2.0 or less).

[0062] [Table 5] Exhaust gas temperature: 603°C, Exhaust gas volume: 742kg / s

[0063] Table 6 shows calculation conditions and estimation results in the cold-heat utilizing type gas turbine power generation system 100 of the second embodiment (dry type). As can be seen from the table, the total power generation output when using about 6.2 kg / s of liquid hydrogen LH2 is about 487 MW, and high power generation efficiency can be obtained.

[0064] [Table 6] Second Embodiment Inlet air (atmospheric) temperature 4℃ Inlet (atmospheric) pressure 100kPa Intake (atmospheric) flow 729kg / s Fuel (hydrogen) usage 6.2kg / s Gas turbine power output 347MW Nitrogen cycle power generation output 32MW Carbon dioxide cycle power generation output 107MW Total power output 487MW Power generation efficiency (LHV, transmission end) 65.6％

[0065] The cold heat type gas turbine power generation system 100 according to the above-mentioned first and second embodiments has the following advantages over the hydrogen-oxygen combustion type turbine power generation system.

[0066] (1) In a hydrogen-oxygen combustion type turbine power generation system, oxygen required for the combustion of hydrogen needs to be produced using oxygen production equipment, and the energy loss of the oxygen production equipment is large. In contrast, in the cold-heat type gas turbine power generation system 100, only a necessary amount of hydrogen is produced (separated) by the air-to-liquid separation device 10 using the cold heat of liquid hydrogen, so the required power of the air-to-liquid separation device 10 is small.

[0067] (2) In a hydrogen-oxygen combustion type turbine power generation system, the turbine inlet temperature becomes high during the combustion of hydrogen and oxygen (pure oxygen), and therefore the recirculation of steam or water is essential. As a result, the compressor power increases, and the turbine and condenser become larger. In the cold-heat gas turbine power generation system 100 , liquid oxygen LO2 produced by the air liquefaction separation device 10 is pressurized in a liquid state through the pressurized oxygen supply line 52 , heated by the nitrogen cooler 48 , and supplied to the gas turbine combustor 24 as pressurized oxygen. Therefore, by compressing only air corresponding to the oxygen shortage in the gas turbine combustor 24 using the gas turbine compressor 22, the turbine inlet temperature can be optimized without recirculating steam or water, and the gas turbine compressor 22 and the gas turbine 26 can be miniaturized.

[0068] (3) The hydrogen-oxygen combustion turbine power generation system is a composite cycle of the Brayton cycle and the Rankine cycle. Other bottom cycles cannot be applied to the upstream of the Rankine cycle. In contrast, in the cold-heat type gas turbine power generation system 100, the bottoming cycle utilizing the exhaust gas of the gas turbine can be freely set, and in particular, in the nitrogen cycle 40 described above, a power generation efficiency of 97% or more can be obtained.

[0069] (4) In a hydrogen-oxygen combustion type turbine power generation system, as described above, if hydrogen and oxygen are not burned at a stoichiometric ratio, residual oxygen (or residual hydrogen) will be mixed in the combustion gas, which will cause the system to fail to function. In addition, in reality, complete combustion cannot be achieved at an equivalence ratio of 1. In contrast, in the cold-heat type gas turbine power generation system 100, combustion can be performed stably and completely at an air-fuel ratio with a residual oxygen concentration of 16% (dry oxygen) in the exhaust gas by the same method as in the conventional GTCC.

[0070] As described above, according to the embodiment of the present invention, in the air liquefaction separation device 10, air is liquefied by cooling and heating the liquid hydrogen LH2 to produce a necessary amount of hydrogen H2, so that the energy loss of the air liquefaction separation device 10 can be suppressed to a minimum.

[0071] The liquid oxygen LO2 produced by the air liquefaction separation device 10 together with the hydrogen H2 is less than the amount of oxygen required in the gas turbine generator 20. However, the liquid oxygen LO2 is pressurized in a liquid state by the pressurized oxygen supply line 52, heated by the nitrogen cooler 48, and supplied to the gas turbine generator 20 as pressurized oxygen. As a result, the compression power of the air compressed by the gas turbine generator 20 can be reduced by an amount equivalent to about 5 times the pressurized oxygen. In addition, in the gas turbine generator 20, the hydrogen H2 produced by the air liquefaction separation device 10 is burned in an oxygen-rich manner using compressed air and pressurized oxygen, so that the hydrogen H2 can be stably burned with a sufficient amount of oxygen.

[0072] 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 cooler 48, and additionally supplied as pressurized nitrogen gas to the high-pressure nitrogen gas of the nitrogen cycle 40. As a result, 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.

[0073] In addition, the reburning burner 32 utilizes the residual oxygen to burn the hydrogen H2 produced by the air liquefaction separation device 10 to heat the exhaust gas temperature, so that the high-temperature exhaust gas can be used to fully heat the high-pressure nitrogen of the nitrogen cycle 40, thereby improving the efficiency of the nitrogen cycle 40.

[0074] That is, the liquid oxygen LO2 produced together with the necessary amount of hydrogen H2 in the air liquefaction separation device 10 contributes to power reduction and oxygen-rich combustion of the gas turbine generator 20 , and the liquid nitrogen LN2 contributes to increase in power generation using the nitrogen cycle 40 .

[0075] Furthermore, by providing the steam cycle 60 or the carbon dioxide cycle 70 on the downstream side of the nitrogen cycle 40, the cold heat of the liquid hydrogen LH2 can be effectively utilized as a whole to produce oxygen for combustion and improve power generation efficiency.

[0076] According to the first embodiment (wet type) of the present invention, the power generation efficiency is estimated to be 70.2% (LHV) under the same turbine inlet temperature / pressure conditions as the 1600°C class LNG incineration GTCC, which is 5.5 to 8 percentage points higher than the approximately 62% to 65% of the hydrogen-oxygen combustion type turbine power generation system.

[0077] Furthermore, the cold-heat gas turbine power generation system 100 of the second embodiment (dry type) does not use a steam turbine, and thus has the following advantages. (1) No water treatment system that is difficult to maintain is required. (2) The large amount of condensation cooling water required by the steam turbine is not required. (3) It can be installed inland where there is little cooling water such as seawater, thereby increasing the freedom of installation of power plants. (4) The final stage of the steam turbine is enlarged for the purpose of pressure reduction operation, but the nitrogen cycle 40 and the carbon dioxide cycle 70 of the first embodiment are operated at high pressure and can be miniaturized.

[0078] The power generation efficiency of the second embodiment is about 4.6% lower than that of the first embodiment, which is 65.6%, but still higher than that of the hydrogen-oxygen combustion turbine power generation system. Therefore, the second embodiment can also be said to be a compact and efficient power generation system with high freedom of power plant installation.

[0079] In addition, the present invention is not limited to the above-mentioned embodiment, and various modifications can be added without departing from the scope of the present invention. Explanation of symbols

[0080] Air, G1 combustion gas, G2 exhaust gas, He helium, H2 hydrogen, LH2 liquid hydrogen, LO2 liquid oxygen, LN2 liquid nitrogen, N2 nitrogen, O2 oxygen, S water vapor, W1 condensed water, W2 pressurized water, 10 air liquefaction separation device, 11 air compressor, 12 nitrogen cooler, 12a hot and cold heat exchanger, 12b N2 circulation machine, 14 helium cooler, 14a liquefaction heat exchanger, 14b He cycle machine, 15 expansion valve, 16 gas-liquid separator, 17 gas compressor, 20 gas turbine generator, 22 gas turbine compressor, 24 gas turbine burner, 26 gas turbine, 30 bottom cycle, 32 reburning burner, 40 nitrogen cycle, 42 nitrogen compressor, 44 nitrogen heater, 44a 1st gas heater, 44b 2nd gas heater, 44c 3rd gas heater, 46 nitrogen turbine, 46a 1st expander, 46b 2nd expander, 46c 3rd expander, 48 nitrogen cooler, 52 pressurized oxygen supply line, 52a liquid oxygen pump, 54 pressurized nitrogen supply line, 54a liquid nitrogen pump, 60 water vapor cycle, 62 pressurization pump, 6 4 Steam heater, 66 Steam turbine, 68 Condenser, 70 Carbon dioxide cycle, 72 Carbon dioxide compressor, 72a First gas compressor, 72b Second gas compressor, 72c Third gas compressor, 73 Cooling tower, 74 Carbon dioxide heater, 74a First gas heater, 74b Second gas heater, 74c Third gas heater, 76 Carbon dioxide expander, 76a First expander, 76b Second expander, 76c Third expander, 78 Carbon dioxide cooler, 78a First cooler, 78b Second cooler, 78c Third cooler, 79 Carbon dioxide heat exchanger, 100 Cold and hot type gas turbine power generation system.

Claims

1. A cold and hot gas turbine power generation system, comprising: An air liquefaction separation plant, which liquefies air by the cold and heat of liquid hydrogen, and produces liquid oxygen and liquid nitrogen together with the necessary amount of hydrogen; a gas turbine generator that generates electricity by subjecting the hydrogen to oxygen-enriched combustion; a reburner that utilizes the remaining oxygen to burn the hydrogen to heat the exhaust gas of the gas turbine generator; A nitrogen cycle having a nitrogen cooler for cooling low-pressure nitrogen by exchanging heat between the liquid oxygen and the liquid nitrogen, so that the nitrogen is circulated to recover power generation power; a pressurized oxygen supply line that pressurizes the liquid oxygen produced by the air liquefaction separation device in a liquid state, heats the pressurized liquid oxygen by the nitrogen cooler, and supplies the pressurized liquid oxygen to the gas turbine generator as pressurized oxygen; and A pressurized nitrogen supply line pressurizes the liquid nitrogen produced by the air liquefaction separation device in a liquid state, heats the pressurized liquid nitrogen by the nitrogen cooler, and supplies it as pressurized nitrogen gas to the high-pressure nitrogen gas in the nitrogen cycle.

2. The cold-heat type gas turbine power generation system according to claim 1, wherein: On the downstream side of the nitrogen cycle, there is a water vapor cycle for circulating water vapor to recover electric power from the exhaust gas or a carbon dioxide cycle for circulating carbon dioxide to recover electric power from the exhaust gas.

3. The cold-heat type gas turbine power generation system according to claim 1, wherein: The air liquefaction separation device comprises: a nitrogen cooler for circulating nitrogen between the liquid hydrogen and the air to indirectly cool the air; as well as A helium cooler circulates helium between the liquid hydrogen and the air to indirectly cool the air.

4. The cold-heat type gas turbine power generation system according to claim 2, wherein: The nitrogen cycle further comprises: a nitrogen compressor for compressing low-pressure nitrogen; a nitrogen heater for heating high-pressure nitrogen using high-temperature exhaust gas from the reburning burner; and a nitrogen turbine for recovering power generation from the heated high-pressure nitrogen.

5. The cold-heat type gas turbine power generation system according to claim 4, wherein: The nitrogen cycle has: a replenishing port, which is provided between the outlet of the nitrogen compressor and the inlet of the nitrogen heater, for replenishing the pressurized nitrogen; and The extraction port is arranged between the outlet of the nitrogen turbine and the inlet of the nitrogen cooler, and extracts the remaining low-pressure nitrogen to the outside.

6. The cold-heat gas turbine power generation system according to claim 4, wherein: The carbon dioxide cycle comprises: a carbon dioxide compressor, which compresses carbon dioxide; a carbon dioxide heater, which utilizes the high-temperature exhaust gas of the nitrogen heater to heat the pressurized carbon dioxide to generate high-pressure and high-temperature carbon dioxide; a carbon dioxide expander, which recovers power generation from the high-pressure and high-temperature carbon dioxide; and a carbon dioxide cooler, which cools the low-pressure carbon dioxide.

7. The cold-heat type gas turbine power generation system according to claim 4, wherein: The steam cycle includes: a pressure pump that pressurizes condensed water; a steam heater that uses the high-temperature exhaust gas of the nitrogen heater to heat the pressurized water to generate high-pressure and high-temperature steam; a steam turbine that recovers power generation from the high-pressure and high-temperature steam; and a condenser that cools the low-pressure steam to obtain the condensed water.

8. The cold-heat type gas turbine power generation system according to claim 1, wherein: The gas turbine generator includes: a gas turbine compressor for compressing air; a gas turbine combustor for performing oxygen-enriched combustion on the hydrogen using compressed air and pressurized oxygen; and a gas turbine for generating power using combustion gas.

Images