Compression system

Abstract

A compression system according to the present invention comprises: a multistage centrifugal compressor that compresses hydrogen gas; a gas turbine that drives the multistage centrifugal compressor; an exhaust heat recovery boiler that recovers exhaust heat from exhaust of the gas turbine and generates vapor; an absorption type first refrigerator that generates cold heat using the vapor generated by the exhaust heat recovery boiler as a heating source for regenerating an absorption liquid; and an intermediate cooler that uses the cold heat generated by the first refrigerator to cool the hydrogen gas compressed by the multistage centrifugal compressor.

Description

Compression System

[0001] The present disclosure relates to the configuration of a compression system for compressing hydrogen gas.

[0002] In preparation for the expansion of demand for hydrogen gas, a system that can inexpensively and stably produce and supply high-pressure hydrogen gas is desired. In response to this, systems have been proposed in which low-pressure hydrogen gas generated by electrolysis or other methods is compressed in a compressor to produce high-pressure hydrogen gas for use or storage. However, because hydrogen gas has a small molecular weight, a large amount of energy is required to compress the hydrogen gas to the desired high pressure, which poses a problem of high operating costs.

[0003] Patent Document 1 discloses a configuration in which hydrogen gas is compressed in stages using a low-pressure sub-stage and a final-pressure sub-stage. The low-pressure sub-stage includes a plurality of compression units arranged in series and a heat exchanger arranged between the plurality of compression units to lower the temperature of the hydrogen by intercooling. Each compression unit includes a barrel compressor, a gearbox connected to a drive shaft of the barrel compressor, and a drive electric motor operably connected to the gearbox to drive the barrel compressor.

[0004] JP 2024-514765 A

[0005] The inventors of the present application are considering using a gas turbine to drive a hydrogen gas compressor. A gas turbine can produce higher speeds than a steam turbine of the same size.

[0006] The present disclosure proposes a compression system that compresses hydrogen gas in stages using a compressor driven by a gas turbine as described above, and that can efficiently operate energy within the system.

[0007] In order to solve the above problems, a compression system according to one aspect of the present disclosure includes: a multi-stage centrifugal compressor that compresses hydrogen gas; a gas turbine that drives the multi-stage centrifugal compressor; a heat recovery boiler that recovers waste heat from an exhaust gas of the gas turbine to generate steam; a first absorption refrigerator that generates cold energy using the steam generated in the heat recovery boiler as a heat source for regenerating an absorption liquid; and an intercooler that cools the hydrogen gas compressed by the multi-stage centrifugal compressor with the cold energy generated in the first refrigerator.

[0008] According to the present disclosure, it is possible to propose a compression system that compresses hydrogen gas in stages using a compressor driven by a gas turbine, and that can efficiently use energy within the system.

[0009] Fig. 1 is a block diagram showing an overall configuration of a compression system according to an embodiment of the present disclosure. Fig. 2 is a block diagram showing a schematic configuration of a first refrigerator. Fig. 3 is a block diagram showing a configuration of a control system of the compression system. Fig. 4 is a flow diagram of optimization calculation of fuel consumption. Fig. 5 is a flow diagram of compressor power calculation. Fig. 6 is a flow diagram of flow control of a first steam amount.

[0010] Next, an embodiment of the present disclosure will be described with reference to the drawings. FIG. 1 is a block diagram showing the overall configuration of a compression system 1 according to an embodiment of the present disclosure. As shown in FIG. 1, the compression system 1 includes a hydrogen gas compressor 2, a gas turbine 3 that drives the hydrogen gas compressor 2, a heat recovery boiler 4 that recovers exhaust heat from the gas turbine 3, a first refrigerator 5, a second refrigerator 6, and a control device 8 that controls the operation of the compression system 1. The compression system 1 compresses low-pressure hydrogen gas to produce high-pressure hydrogen gas. The high-pressure hydrogen gas has a pressure appropriate for the application. The high-pressure hydrogen gas produced by the compression system 1 can be used as fuel or stored in a storage tank.

[0011] <Hydrogen Gas Compressor 2> The hydrogen gas compressor 2 is a multi-stage centrifugal compressor that compresses hydrogen gas in stages. The hydrogen gas compressor 2 includes a casing 20, a rotating shaft 21 rotatably supported by the casing 20, and multiple impellers 22 disposed inside the casing 20 and fixed to the rotating shaft 21. The casing 20 is provided with an intake passage that draws in hydrogen gas and sends it to the first-stage impeller 22, a stationary passage that sends hydrogen gas discharged from the impeller 22 to the next-stage impeller 22, and a discharge passage that discharges gas from the final-stage impeller 22 to the outside. A combination of the impeller 22 and the stationary passage constitutes a stage that serves as a unit of pressure increase in the hydrogen gas compressor 2, and the hydrogen gas compressor 2 has multiple compression stages. The hydrogen gas drawn into the hydrogen gas compressor 2 is pressurized in stages as it passes through each compression stage consisting of the impeller 22 and the stationary passage, and is then discharged to the outside.

[0012] In a multi-stage compressor, gas is compressed in stages to a predetermined pressure, and the gas temperature at the inlet of each stage increases with the stage's progress. The work required to compress gas increases in proportion to the gas temperature at the inlet of each stage. Therefore, the hydrogen gas compressor 2 has an intermediate cooling flow path 26 that cools the hydrogen gas between multiple compression stages in order to reduce the compression power by lowering the gas temperature at the inlet of each stage. The intermediate cooling flow path 26 is configured to extract hydrogen gas from any of the multiple compression stages except the final stage to the outside, cool the extracted hydrogen gas in an intermediate cooler 25, and return the cooled hydrogen gas to the inlet of the next stage.

[0013] In the hydrogen gas compressor 2 according to this embodiment, the multiple compression stages are divided into a first compression section S1 consisting of one or more consecutive front-end stages and a second compression section S2 consisting of one or more consecutive rear-end stages, and the outlet of the first compression section S1 and the inlet of the second compression section S2 are connected by an intermediate cooling channel 26. As a result, the hydrogen gas discharged from the first compression section S1 is cooled in the intermediate cooler 25 and enters the second compression section S2. However, the arrangement of the intermediate cooling channel 26 is not limited to this embodiment. The intermediate cooling channel 26 only needs to be provided in at least one location between the multiple compression stages, and may be provided in multiple locations.

[0014] <<Gas Turbine 3 >> The gas turbine 3 includes a turbine 31 , an air compressor 32 , and a combustor 33 .

[0015] The air compressor 32 draws in and compresses combustion air, and discharges the pressurized combustion air to the combustor 33. The air compressor 32 is provided with an intake air cooler 35 that cools the intake air of the air compressor 32. Cooling the intake air of the air compressor 32 by the intake air cooler 35 allows the compression power of the air compressor 32 to be reduced.

[0016] The combustor 33 burns fuel with high-pressure combustion air supplied from the air compressor 32 to generate high-temperature, high-pressure gas. The fuel for the combustor 33 is not particularly limited, but may be hydrogen gas. When the fuel is hydrogen gas, the high-pressure hydrogen gas generated by the hydrogen gas compressor 2 may be used as the fuel.

[0017] The turbine 31 has an impeller fixed to an output shaft 34, and high-temperature, high-pressure gas generated in the combustor 33 is directed against the impeller to rotate the impeller. The high-temperature, high-pressure gas expands to atmospheric pressure in the turbine 31, and the heat and pressure of the high-temperature, high-pressure gas are converted into rotational energy for the output shaft 34. The output shaft 34 is connected to the air compressor 32, and a portion of the rotational energy of the output shaft 34 is used to rotate the air compressor 32. The output shaft 34 is also connected to the rotating shaft 21 of the hydrogen gas compressor 2 via a power transmission mechanism 50. The rotational power extracted from the output shaft 34 by operation of the gas turbine 3 is transmitted to the rotating shaft 21 of the hydrogen gas compressor 2 via the power transmission mechanism 50 and used to drive the hydrogen gas compressor 2. In addition to transmitting power, the power transmission mechanism 50 has the function of adjusting the torque and speed of the rotation transmitted from the output shaft 34 to the rotating shaft 21 of the hydrogen gas compressor 2 so that the rotating shaft 21 of the hydrogen gas compressor 2 rotates at a desired rotational speed.

[0018] <<Heat Recovery Steam Generator 4>> The high-temperature exhaust gas discharged from the gas turbine 3 is introduced into the heat recovery steam generator 4. The heat recovery steam generator 4 recovers heat from the exhaust gas of the gas turbine 3 and uses the recovered heat to heat water and generate steam. The steam generated in the heat recovery steam generator 4 is sent to the first chiller 5 and the second chiller 6 through a steam supply pipe 40. A steam distribution valve 44 is provided in the steam supply pipe 40. The opening of the steam distribution valve 44 is controlled by the control device 8. The steam distribution valve 44 is, for example, a flow rate adjustment valve, and by adjusting the valve opening, distributes the amount of steam generated in the heat recovery steam generator 4 and introduced into the steam supply pipe 40 to the first chiller 5 and the second chiller 6. The first steam amount supplied to the first chiller 5 is detected by a first flow meter 81. The second steam amount supplied to the second chiller 6 is detected by a second flow meter 82. The first flow meter 81 and the second flow meter 82 are electrically connected to the control device 8 , and the steam amounts detected by these flow meters 81 , 82 are output to the control device 8 .

[0019] <<First Refrigerator 5>> Fig. 2 is a block diagram showing a schematic configuration of the first refrigerator 5. As shown in Fig. 2, the first refrigerator 5 is an absorption refrigerator including an evaporator 51, an absorber 52, a regenerator 53, a condenser 54, and a cooling tower 55. The cooling tower 55 cools the cooling water circulating through a cooling water circulation path 58. The cooling water circulation path 58 is a circulation flow path for the cooling water that leaves the cooling tower 55, passes through the condenser 54, and returns to the cooling tower 55.

[0020] The inside of the evaporator 51 is at a low pressure close to a vacuum, and a nozzle for dripping or spraying water is provided at the top of the evaporator 51. Water may be stored at the bottom of the evaporator 51. A refrigerant pipe 56 passes through the evaporator 51. The refrigerant pipe 56 is a pipe that forms a circulation path for refrigerant circulating through the intercooler 25 and the evaporator 51 of the first refrigerator 5. Water dropping from the top of the evaporator 51 evaporates into water vapor in a low-temperature, low-pressure environment, and the water vapor exchanges heat with the refrigerant flowing through the refrigerant pipe 56, thereby removing heat from the refrigerant. The refrigerant circulating through the refrigerant pipe 56 in this way is cooled in the evaporator 51, moves to the intercooler 25, is warmed by heat exchange with high-temperature gas passing through the intercooling flow path 26, and returns to the evaporator 51 again.

[0021] The top of the evaporator 51 is connected to the top of the absorber 52, and water vapor generated in the evaporator 51 flows into the absorber 52. Nozzles for spraying or dropping an absorbing liquid are provided at the top of the absorber 52. The absorbing liquid is a liquid that absorbs water, such as a sodium chloride aqueous solution or a lithium bromide aqueous solution. The inside of the absorber 52 is cooled by cooling water circulating through a cooling water circulation path 58. The absorbing liquid dropping from the top of the absorber 52 absorbs the water vapor that has flowed into the absorber 52. The absorbing liquid, which has been diluted by absorbing the water vapor, accumulates in the bottom of the absorber 52.

[0022] The absorption liquid accumulated in the lower part of the absorber 52 is sent to the regenerator 53 and stored in the lower part of the regenerator 53. The regenerator 53 is provided with a heating device 57 that heats the absorption liquid with steam supplied from the heat recovery boiler 4 through the steam supply pipe 40. The heating device 57 is formed, for example, by a steam pipe passing through the regenerator 53, and the steam supplied from the heat recovery boiler 4 is introduced into this steam pipe. In the regenerator 53, the absorption liquid diluted in the absorber 52 is heated by the heating device 57, thereby evaporating the water in the absorption liquid and separating steam from the absorption liquid. The absorption liquid concentrated by separating the steam is sent to the absorber 52. The upper part of the regenerator 53 is connected to the upper part of the condenser 54, and the steam separated from the absorption liquid in the regenerator 53 flows into the condenser 54.

[0023] The inside of the condenser 54 is cooled by cooling water circulating through a cooling water circulation path 58. The water vapor that flows into the condenser 54 is cooled and liquefied in the condenser 54, and becomes water, which accumulates in the lower part of the condenser 54. The water that accumulates in the lower part of the condenser 54 is returned from the condenser 54 to the evaporator 51, and is used again in the evaporator 51.

[0024] The first refrigerator 5 configured as described above uses the thermal energy of the steam generated in the heat recovery boiler 4 to cool the refrigerant flowing through the refrigerant pipe 56. In other words, the first refrigerator 5 uses the thermal energy of the steam generated in the heat recovery boiler 4 to generate cold energy that is used to cool the gas in the intercooler 25 of the hydrogen gas compressor 2.

[0025] <<Second Refrigerator 6>> Returning to Fig. 1 , the second refrigerator 6 is an absorption refrigerator having substantially the same configuration as the first refrigerator 5. By referring to the description of the first refrigerator 5, detailed description of the second refrigerator 6 will be omitted. A refrigerant pipe 61, through which a refrigerant circulates between the intake air cooler 35 and the evaporator of the second refrigerator 6, passes through the second refrigerator 6. The second refrigerator 6 cools the refrigerant flowing through the refrigerant pipe 61 by utilizing the thermal energy of steam generated in the heat recovery boiler 4. In other words, the second refrigerator 6 generates cold energy that is used to cool the intake air in the intake air cooler 35 of the air compressor 32 of the gas turbine 3 by utilizing the thermal energy of the steam generated in the heat recovery boiler 4.

[0026] <<Control Device 8>> The control device 8 can be realized by, for example, a computer including a CPU (Central Processing Unit), memory, an auxiliary storage device such as an HDD (Hard Disk Drive), a communication I / F for connecting to a communication network or other devices via a wired or wireless connection, an input device such as a mouse, keyboard, touch sensor, or touch panel, and an output device such as a liquid crystal display. FIG. 3 is a block diagram showing the configuration of the control system of the compression system 1. As shown in FIG. 3, the control device 8 has functional units, including a fuel consumption calculator 80 and a flow rate controller 79 that controls the steam distribution valve 44. These functional units of the control device 8 can be realized by loading a predetermined program stored in the auxiliary storage device into the memory and executing it on the CPU.

[0027] The control device 8 is electrically connected to various meters, including a first flow meter 81, a second flow meter 82, a first suction thermometer 63, a first suction flow meter 64, a first suction pressure gauge 65, a first discharge pressure gauge 66, a first discharge thermometer 67, a second suction thermometer 83, a second suction flow meter 84, a second suction pressure gauge 85, a second discharge pressure gauge 86, an intake thermometer 87, and a rotational speed meter 88. The first suction thermometer 63 detects a first suction temperature, which is the temperature of gas entering the first compression section S1 of the hydrogen gas compressor 2. The first suction flow meter 64 detects a first suction flow rate, which is the flow rate of gas entering the first compression section S1. The first suction pressure gauge 65 detects a first suction pressure, which is the pressure of gas entering the first compression section S1. The first discharge pressure gauge 66 detects a first discharge pressure, which is the pressure of gas exiting the first compression section S1, i.e., the gas entering the intercooler 25. The first discharge thermometer 67 detects a first discharge temperature, which is the temperature of the gas exiting the first compression section S1. The second suction thermometer 83 detects a second suction temperature, which is the temperature of the gas entering the second compression section S2 of the hydrogen gas compressor 2, i.e., the temperature of the gas exiting the intercooler 25. The second suction flow meter 84 detects a second suction flow rate, which is the flow rate of the gas entering the second compression section S2. The second suction pressure gauge 85 detects a second suction pressure, which is the pressure of the gas entering the second compression section S2. The second discharge pressure gauge 86 detects a second discharge pressure, which is the pressure of the gas exiting the second compression section S2. The intake air thermometer 87 detects the temperature of the combustion air flowing into the intake air cooler 35 attached to the air compressor 32 of the gas turbine 3. The tachometer 88 detects the rotational speed of the rotary shaft 21 of the hydrogen gas compressor 2.

[0028] In the compression system 1, the amount of steam generated by the heat recovery steam generator 4 is proportional to the fuel consumption of the gas turbine 3. In other words, an increase in fuel consumption increases the amount of steam generated, and a decrease in fuel consumption decreases the amount of steam generated. Reducing the fuel consumption of the gas turbine 3 reduces the energy consumption of the compression system 1, thereby contributing to reducing the operating costs of the compression system 1. Meanwhile, the first and second refrigerators 5 and 6, which use the steam generated by the heat recovery steam generator 4 to generate cold energy, cool the gas, thereby reducing the compression power required by the hydrogen gas compressor 2 and the air compressor 32. Therefore, if the amount of steam generated is insufficient, the gas cooling is insufficient, reducing the effect of reducing the compression power. Therefore, the control device 8 of the compression system 1 performs an optimization calculation for fuel consumption to minimize the fuel consumption of the gas turbine 3 while satisfying the reduction in compression power required by the hydrogen gas compressor 2 and the air compressor 32 due to gas cooling by the first and second refrigerators 5 and 6, and the supply of rotational power to the hydrogen gas compressor 2 to achieve the required compression ratio. More specifically, the fuel consumption calculator 80 of the control device 8 acquires the process values ​​of the compression system 1 output from the various instruments described above, and based on these values, performs the optimization calculation of the fuel consumption described below to calculate the first steam amount setting value 99.

[0029] Fig. 4 is a flowchart of an optimization calculation of fuel consumption. As shown in Fig. 4, a fuel consumption calculator 80 of a control device 8 includes an optimization calculation unit 71, a first chiller performance calculation unit 72, an intercooler performance calculation unit 73, a compressor power calculation module 74, a second chiller performance calculation unit 75, an inlet air cooler performance calculation unit 76, and a gas turbine performance calculation unit 77. The fuel consumption calculator 80 receives a total steam amount 90 of the heat recovery steam generator 4 as an input and outputs a first steam amount set value 99, which is a set value of the steam amount supplied to the first chiller 5. The total steam amount 90 is the sum of a detected value of the first steam amount detected by a first flow meter 81 and a detected value of the second steam amount detected by a second flow meter 82.

[0030] The optimization calculation unit 71 generates a plurality of mutually different first steam flow assumed values ​​91 in accordance with a predetermined generation rule from the total steam flow rate 90 of the heat recovery boiler 4. For example, the optimization calculation unit 71 generates m mutually different first steam flow assumed values ​​91 ranging from 1 to m. Here, m is a natural number, and the value of m is not particularly limited, but it is preferable that it not be an enormous number from the viewpoint of simplifying the calculation.

[0031] The first steam amount assumed value 91 generated by the optimization calculation unit 71 is output to the first chiller performance calculation unit 72. The first chiller performance calculation unit 72 uses a predetermined numerical map to calculate a first refrigerant temperature 93 corresponding to the first steam amount assumed value 91. The first refrigerant temperature 93 is the temperature of the refrigerant that has been cooled by the first chiller 5 and then flows out of the first chiller 5 when steam having the first steam amount assumed value 91 is supplied to the first chiller 5. In other words, the first refrigerant temperature 93 is substantially equal to the temperature of the refrigerant that flows into the economizer 25. The first chiller performance calculation unit 72 outputs the calculated first refrigerant temperature 93 to the economizer performance calculation unit 73.

[0032] The intercooler performance calculation unit 73 calculates a second suction temperature 95 from the first refrigerant temperature 93 and the first discharge temperature detected by the first discharge thermometer 67, using a predetermined numerical map. The second suction temperature 95 is the temperature of the gas entering the second compression section S2 of the hydrogen gas compressor 2. The second suction temperature 95 is substantially equal to the outlet gas temperature of the intercooler 25. The intercooler performance calculation unit 73 outputs the calculated second suction temperature 95 to the compressor power calculation module 74.

[0033] The calculated second suction temperature 95 is input to the compressor power calculation module 74. The following process values ​​are input to the compressor power calculation module 74: the first suction temperature detected by the first suction thermometer 63, the first suction flow rate detected by the first suction flow meter 64, the first suction pressure detected by the first suction pressure gauge 65, the first discharge pressure detected by the first discharge pressure gauge 66, the second suction flow rate detected by the second suction flow meter 84, the second suction pressure detected by the second suction pressure gauge 85, the second discharge pressure detected by the second discharge pressure gauge 86, and the rotational speed detected by the rotational speed meter 88.

[0034] The compressor power calculation module 74 uses the above process values ​​to calculate the shaft power 97 corresponding to the operating status of the hydrogen gas compressor 2. Fig. 5 is a compressor power calculation flow diagram by the compressor power calculation module 74. As shown in Fig. 5, the compressor power calculation module 74 has a polytropic head calculation unit 46, a polytropic efficiency calculation unit 47, a section power calculation unit 48, and a shaft power calculation unit 49.

[0035] The polytropic head calculation unit 46 calculates the polytropic head of the first compression section S1 using an arithmetic formula based on the input first suction temperature, first suction pressure, and first discharge pressure. The polytropic head is an index representing the energy required to pressurize 1 kg of gas to a predetermined pressure. The arithmetic formula for the polytropic head is given by the following (Equation 1).

[0036]

[0037] In Equation 1, the gas constant R and compression coefficient Z are parameters determined by the gas to be compressed and are given in advance. The polytropic exponent n is a constant. Similarly, the polytropic head calculation unit 46 calculates the polytropic head of the second compression section S2 using an arithmetic formula from the input second suction temperature, second suction pressure, and second discharge pressure.

[0038] The polytropic efficiency calculation unit 47 calculates the polytropic efficiency of the first compression section S1 using a numerical map based on the input rotational speed and first suction flow rate. Polytropic efficiency is the ratio of the work calculated assuming compression occurs along a polytropic change to the actual work. An efficiency characteristic map showing the relationship between the rotational speed, suction flow rate, and polytropic efficiency is provided in advance to the polytropic efficiency calculation unit 47. This efficiency characteristic map can be used to calculate the polytropic efficiency corresponding to the operating point of the hydrogen gas compressor 2. The operating point represents the operating status of the hydrogen gas compressor 2. Similarly, the polytropic efficiency calculation unit 47 calculates the polytropic efficiency of the second compression section S2 using the numerical map of polytropic efficiency based on the input rotational speed and second suction flow rate.

[0039] The section power calculation unit 48 calculates the section power of the first compression section S1 using a calculation formula based on the polytropic head of the first compression section S1, the polytropic efficiency of the first compression section S1, and the first suction flow rate. The calculation formula for the section power is the following (Equation 2).

[0040]

[0041] Similarly, the section power calculation unit 48 calculates the section power of the second compression section S2 using an arithmetic formula from the polytropic head of the second compression section S2, the polytropic efficiency of the second compression section S2, and the second suction flow rate.

[0042] The shaft power calculation unit 49 calculates the shaft power of the hydrogen gas compressor 2, which is the sum of the section power of the first compression section S1 and the section power of the second compression section S2.

[0043] Returning to the fuel consumption optimization calculation flow diagram of FIG. 4 , the second chiller performance calculation unit 75 uses a predetermined numerical map to calculate a corresponding second refrigerant temperature 94 from the second assumed steam amount value 92. The second assumed steam amount value 92 is a value obtained by subtracting the first assumed steam amount value 91 from the total steam amount 90. The second refrigerant temperature 94 is the temperature of the refrigerant that is cooled in the second chiller 6 and then flows out of the second chiller 6 when steam corresponding to the second assumed steam amount value 92 is supplied to the second chiller 6. In other words, the second refrigerant temperature 94 is substantially equal to the temperature of the refrigerant that flows into the intake air cooler 35. The second chiller performance calculation unit 75 outputs the calculated second refrigerant temperature 94 to the intake air cooler performance calculation unit 76.

[0044] The intake-air cooler performance calculation unit 76 uses a predetermined numerical map to determine a corresponding combustion air temperature 96 from the second refrigerant temperature 94 and the temperature of the combustion air entering the intake-air cooler 35 detected by the intake-air thermometer 87. The combustion air temperature 96 is the temperature of the combustion air entering the air compressor 32 of the gas turbine 3. The combustion air temperature 96 is substantially equal to the temperature of the combustion air after being cooled by heat exchange with the refrigerant in the intake-air cooler 35. The intake-air cooler performance calculation unit 76 outputs the determined combustion air temperature 96 to the gas turbine performance calculation unit 77.

[0045] The gas turbine performance calculation unit 77 uses a predetermined numerical map to determine the corresponding fuel consumption amount 98 from the shaft power 97, the combustion air temperature 96, and the rotational speed of the rotating shaft 21 of the hydrogen gas compressor 2 detected by the tachometer 88. The gas turbine performance calculation unit 77 outputs the determined fuel consumption amount 98 to the optimization calculation unit 71.

[0046] The above process of calculating the fuel consumption 98 from the total steam amount 90 is performed on m mutually different first steam amount assumed values ​​91 from 1 to m, thereby calculating the fuel consumption 98 corresponding to each of the m first steam amount assumed values ​​91. The optimization calculation unit 71 extracts, from the m first steam amount assumed values ​​91, the one that minimizes the fuel consumption 98 as an optimal value, and outputs the extracted first steam amount assumed value 91 to the flow rate controller 79 as the first steam amount set value 99. In other words, the one that minimizes the fuel consumption 98 is searched for among the m first steam amount assumed values ​​91, and the first steam amount assumed value 91 obtained as a solution is set as the first steam amount set value 99. Note that, although the first steam amount assumed value 91 is calculated in the above optimization calculation of the fuel consumption, the second steam amount assumed value 92 may be calculated instead of the first steam amount assumed value 91.

[0047] The flow rate controller 79 of the control device 8 controls the aperture of the steam distribution valve 44 so that the steam rate detected by the first flow meter 81, i.e., the steam rate supplied to the first refrigerator 5, becomes the first steam rate set value 99 calculated by the fuel consumption calculator 80. FIG. 6 is a flow chart of the flow rate control of the first steam rate. As shown in FIG. 6 , the flow rate controller 79 according to this embodiment has a PID controller. The PID controller receives an error between the first steam rate set value 99 and the first steam rate detected by the first flow meter 81. The PID calculator calculates an operation amount for the actuator of the steam distribution valve 44 from the input error. The flow rate controller 79 outputs the calculated operation amount to the actuator of the steam distribution valve 44. This changes the valve aperture of the steam distribution valve 44, thereby changing the first steam rate. The changed first steam rate is fed back, and the processing loop is repeated, so that the first steam rate approaches the first steam rate set value 99. In this way, depending on the operating state of the hydrogen gas compressor 2, the amount of steam sent to the first chiller 5 that generates the cold energy used in the intercooler 25 and the amount of steam sent to the second chiller 6 that generates the cold energy used in the intake air cooler 35 are optimized so as to minimize the fuel consumption of the gas turbine 3. Note that although the above description has been made on the case where the compression system 1 includes one intercooler 25, even in the case where a plurality of intercoolers 25 are included, the optimized fuel consumption can be obtained by increasing the number of terms in accordance with the number of compression sections of the hydrogen gas compressor 2 and the intercoolers 25, and the amount of steam sent to each chiller can be optimized so as to minimize the fuel consumption of the gas turbine 3.

[0048] [Summary] The compression system 1 according to the first item of the present disclosure includes: a multi-stage centrifugal compressor (corresponding to the hydrogen gas compressor 2 in the above embodiment) that compresses hydrogen gas; a gas turbine 3 that drives the multi-stage centrifugal compressor 2; a heat recovery boiler 4 that recovers waste heat from the exhaust of the gas turbine 3 to generate steam; a first absorption refrigerator 5 that generates cold energy using the steam generated in the heat recovery boiler 4 as a heat source for regenerating an absorption liquid; and an intercooler 25 that cools the hydrogen gas compressed by the multi-stage centrifugal compressor 2 with the cold energy generated in the first refrigerator 5.

[0049] In the compression system 1 configured as described above, cold energy is generated in the first refrigerator 5 using the exhaust heat of the gas turbine 3, which is the driver of the multi-stage centrifugal compressor 2, and the generated cold energy is used to intermediate-cool the hydrogen gas flowing through the multi-stage centrifugal compressor. In this way, by effectively managing energy within the system, the amount of external input energy is reduced, which can contribute to reducing the operating costs of the compression system 1.

[0050] The compression system 1 according to the second item of the present disclosure is the compression system 1 according to the first item, further comprising: a second absorption chiller 6 that generates cold energy using steam generated in the heat recovery boiler 4 as a heat source for regenerating the absorption liquid; and an intake air cooler 35 that cools the combustion air drawn in by the gas turbine 3 with the cold energy generated in the second chiller 6.

[0051] The compression system 1 according to the third item of the present disclosure is the compression system 1 according to the second item, further comprising a steam supply pipe 40 that sends steam from the heat recovery boiler 4 to the first refrigerator 5 and the second refrigerator 6, and a steam distribution valve 44 that distributes the steam sent through the steam supply pipe 40 to the first refrigerator 5 and the second refrigerator 6.

[0052] In the compression system 1 according to the second and third aspects, exhaust heat from the gas turbine 3, which is the driver of the multi-stage centrifugal compressor 2, is used to generate cold energy for intermediate cooling of the hydrogen gas flowing through the multi-stage centrifugal compressor, and cold energy for cooling the combustion air drawn into the gas turbine 3. In this way, by effectively using energy within the system, the input energy from outside is reduced, which can contribute to reducing the operating costs of the compression system 1.

[0053] The compression system 1 according to the fourth item of the present disclosure is the compression system 1 according to the third item, further including a control device 8 configured to calculate a set value 99 of the amount of steam to be sent to the first chiller 5 so that the fuel consumption 98 of the gas turbine 3 is minimized in accordance with the operating state of the multi-stage centrifugal compressor 2, and to control the steam amount distribution valve 44 so that the amount of steam to be sent to the first chiller 5 becomes the set value 99.

[0054] According to the compression system 1 having the above configuration, the amount of fuel consumed by the gas turbine 3 can be reduced, which contributes to energy saving of the entire system.

[0055] A compression system 1 according to a fifth aspect of the present disclosure is the compression system 1 according to the fourth aspect, wherein the control device 8 is configured to: acquire a total steam amount 90 generated in the heat recovery boiler 4, and allocate the total steam amount 90 to a first steam amount assumed value 91 and a second steam amount assumed value 92; calculate a shaft power 97 according to the operating state of the multi-stage centrifugal compressor 2 when the hydrogen gas is cooled in the intercooler 25 using the cold energy generated in the first refrigerator 5 at the steam amount of the first steam amount assumed value 91; calculate a fuel consumption 98 of the gas turbine 3 when the multi-stage centrifugal compressor 2 is driven by the shaft power 97 when the combustion air is cooled in the intake air cooler 35 using the cold energy generated in the second refrigerator 6 at the steam amount of the second steam amount assumed value 92; search for the first steam amount assumed value 91 that minimizes the fuel consumption 98, and set the first steam amount assumed value 91 obtained as a solution as a set value 99 of the steam amount to be sent to the first refrigerator 5.

[0056] According to the compression system 1 having the above configuration, the steam generated in the heat recovery boiler 4 can be suitably distributed to the first refrigerator 5 and the second refrigerator 6 so as to achieve an appropriate relationship between the reduction in compression power due to the intermediate cooling of the multi-stage centrifugal compressor 2, the reduction in compression power of the air compressor 32 due to the intake air cooling of the gas turbine 3, and the reduction in fuel consumption of the gas turbine 3.

[0057] The functions performed by the controller 8 described herein may be implemented in circuitry or processing circuitry, including general-purpose processors, application-specific processors, integrated circuits, ASICs (Application Specific Integrated Circuits), CPUs (Central Processing Units), conventional circuits, and / or combinations thereof, programmed to perform the described functions. Processors include transistors and other circuits and are considered circuitry or processing circuitry. A processor may also be a programmed processor that executes a program stored in memory. In this specification, a circuit, unit, or means is hardware that is programmed to perform or executes the described functions. The hardware may be any hardware disclosed herein or any hardware known to be programmed to perform or execute the described functions. If the hardware is a processor, which is considered a type of circuitry, the circuit, means, or unit is a combination of hardware and software used to configure the hardware and / or processor.

[0058] The above-described embodiments have been presented for purposes of illustration and description and are not intended to limit the present disclosure to the form disclosed herein. For example, in the foregoing detailed description, various features of the present disclosure are grouped together in a single embodiment for the purpose of streamlining the disclosure, but some of the features may also be combined. Furthermore, multiple features included in the present disclosure may also be combined into alternative embodiments, configurations, or aspects other than those discussed above.

[0059] 1: Compression system 2: Hydrogen gas compressor (multi-stage centrifugal compressor) 3: Gas turbine 4: Exhaust heat recovery boiler 5: First refrigerator 6: Second refrigerator 8: Control device 25: Intercooler 31: Turbine 35: Inlet air cooler 40: Steam supply pipe 44: Steam distribution valve

Claims

1. A compression system comprising: a multi-stage centrifugal compressor that compresses hydrogen gas; a gas turbine that drives the multi-stage centrifugal compressor; a heat recovery boiler that recovers waste heat from the exhaust of the gas turbine to generate steam; a first absorption refrigerator that generates cold energy using the steam generated in the heat recovery boiler as a heat source for regenerating an absorption liquid; and an intercooler that cools the hydrogen gas compressed by the multi-stage centrifugal compressor with the cold energy generated in the first refrigerator.

2. The compression system according to claim 1, further comprising: a second absorption chiller that generates cold energy using steam generated in the heat recovery boiler as a heat source for regenerating an absorption liquid; and an intake air cooler that cools combustion air taken in by the gas turbine with the cold energy generated by the second chiller.

3. The compression system according to claim 2, further comprising: a steam supply pipe that sends steam from the heat recovery boiler to the first refrigerator and the second refrigerator; and a steam distribution valve that distributes the steam sent through the steam supply pipe to the first refrigerator and the second refrigerator.

4. The compression system according to claim 3, further comprising a control device configured to calculate a set value of the amount of steam to be sent to the first refrigerator so as to minimize fuel consumption of the gas turbine in accordance with the operating state of the multi-stage centrifugal compressor, and to control the steam distribution valve so that the amount of steam sent to the first refrigerator becomes the set value.

5. The compression system according to claim 4, wherein the control device: acquires the total amount of steam generated in the heat recovery boiler, and divides the total amount of steam into a first steam amount assumed value and a second steam amount assumed value; calculates shaft power according to the operating state of the multi-stage centrifugal compressor when the hydrogen gas is cooled in the intercooler using cold energy generated in the first refrigerator at a steam amount of the first steam amount assumed value; calculates the fuel consumption of the gas turbine when the multi-stage centrifugal compressor is driven by the shaft power when the combustion air is cooled in the intake air cooler using cold energy generated in the second refrigerator at a steam amount of the second steam amount assumed value; searches for the first steam amount assumed value that minimizes the amount of fuel consumption, and sets the first steam amount assumed value obtained as a solution as the set value for the amount of steam to be sent to the first refrigerator.

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