JP5442206B2 - Power system - Google Patents

Description

  The present invention relates to a power system.

For example, as an auxiliary power unit (APU) in an aircraft, Patent Document 1 discloses an electric power system including a hybrid power generation device in which a solid oxide fuel cell (SOFC) and a gas turbine are combined. It is disclosed. In this electric power system, the exhaust of the fuel cell containing unreacted fuel is combusted in the fuel device, the combustion gas is supplied to the turbine of the gas turbine to drive the gas turbine, and the exhaust of the compressor in the gas turbine Is supplied to the fuel cell after exchanging heat with the exhaust of the fuel cell to form hot hot air. With this configuration, the power system disclosed in Patent Document 1 aims to improve efficiency.
US Pat. No. 6,834831

  By the way, for example, when the temperature inside the fuel cell (in the stack) or the like decreases, the power generation efficiency decreases. On the other hand, as for the environment in which the aircraft is used, for example, the outside air pressure and the outside temperature vary greatly between the standby time on the ground and the flight time in the sky. For this reason, assuming the case where a system including a fuel cell as described above is adopted as an electric power system mounted on an aircraft, for example, when the aircraft is flying at high altitude, the fuel cell is compared with that at the time of standby on the ground. Since the temperature and concentration of the supplied air are lowered, there is a problem that the temperature and pressure in the fuel cell are lowered and the power generation efficiency is lowered.

  In addition, the power load on an aircraft varies greatly depending on the operational state of the aircraft. For example, when waiting on the ground, the power load may be significantly lower than when flying over the air. In this way, even if the power load is relatively light, if a large amount of fuel is supplied to the fuel cell so that the output of the power system remains constant at the rated value, the fuel is effectively consumed. It will also throw away without doing, and there is a problem from a viewpoint of energy saving.

  The present invention has been made in view of the above points, and an object of the present invention is to provide a power system including a hybrid power generation device including a fuel cell and a gas turbine. It is to enable stable and economical power generation.

According to an aspect of the present invention, a power system includes a gas turbine including a turbine, a compressor, and a generator, a fuel cell to which exhaust gas from the compressor is supplied, and a fuel supply unit that supplies fuel to the fuel cell. by a hybrid power generator, the control of the fuel supply means and gas turbine performs including, and a control unit for controlling the fuel supply amount及beauty air supply amount to the fuel cell.

According to this configuration, in a hybrid power plant comprising a fuel cell and a gas turbine, the control unit, by performing control of the fuel supply means and the gas turbine, the fuel supply amount及beauty air supply amount to the fuel cell Control. As a result, for example, the power generation efficiency of the fuel cell and the power generation efficiency of the entire power system can be controlled in response to changes in the usage environment of the power system, or the operation status of the power system can be changed. Thus, the fuel consumption can be controlled to be minimized, and stable and economical power generation is realized.

It said hybrid power generator, wherein together with the combustion of the exhaust of the fuel cell, further including a combustor supplies the combustion gas to a turbine of the gas turbine.

  The fuel cell exhaust contains unreacted fuel, but the efficiency of the power system is improved by returning the exhaust to the gas turbine.

The hybrid power generator is an auxiliary power unit mounted on an aircraft, and the control unit is connected to a data bus mounted on the aircraft, and the fuel cell is based on various data from the data bus. that controls the fuel supply amount及beauty air supply amount to.

Based on the various types of data from the data bus of the aircraft, by controlling the fuel supply amount及beauty air supply amount to the fuel cell, in response to the operating environment and operational state of the aircraft, the fuel supply amount及beauty sky The air supply amount can be appropriately controlled.

The power system further includes a heat exchanger interposed between the gas turbine and the fuel cell and exchanging heat between the exhaust of the turbine and the exhaust of the compressor, and the control unit includes: When it is specified that the aircraft is cruising at a high altitude, the amount of unreacted gas in the exhaust of the fuel cell is controlled to be higher than that at a steady time other than during a high altitude cruise. increasing a Rutotomoni increase the temperature of the air supplied to the fuel cell to a predetermined temperature, the pressure of the air supplied to the fuel cell through the control of the gas turbine, from the steady state other than the altitude cruising Also increase .

Thereby, with changes in such aircraft use environment, for example the even when the aircraft is most external atmospheric pressure and ambient temperature or the like by cruising a degree is decreased, the fuel supply amount及beauty air supply amount to the fuel cell By controlling the above, it becomes possible to keep the inside of the fuel cell at least at a predetermined temperature and stably maintain a high power generation efficiency.

  The control unit sends the fuel cell to the fuel cell when the power load on the aircraft is relatively small, based on at least the data related to the hydrogen concentration in the exhaust of the fuel cell and the operation mode data of the aircraft from the data bus. It is also possible to reduce at least the fuel supply amount.

  By reducing the amount of fuel supplied to the fuel cell when the power load is relatively small, wasteful fuel consumption is eliminated and energy saving is achieved. In this case, it is desirable to secure a fuel supply amount at least enough to allow idle operation of the gas turbine, based on data relating to the hydrogen concentration in the exhaust of the fuel cell.

As described above, according to the present invention, in a hybrid power plant comprising a fuel cell and a gas turbine, by performing control of the fuel supply means and the gas turbine, the fuel supply amount及beauty air supply to the fuel cell The amount can be optimized in terms of power generation efficiency and energy saving, and stable and economical power generation can be realized.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. It should be noted that the following description of the preferred embodiment is merely illustrative in nature, and is not intended to limit the present invention, its application, or its use.

  FIG. 1 is a schematic diagram illustrating a configuration of a power system according to an embodiment of the present invention. In this embodiment, this power system is configured as an APU of an aircraft. Note that the power system of the present invention is not limited to a system mounted on an aircraft, and may be a power system mounted on other transport equipment such as a ship or an automobile. In addition, the power system of the present invention is not limited to a system mounted on a transport device, but may be employed in other power systems such as a portable generator system.

  In FIG. 1, reference numeral 1 denotes a fuel cell including an anode 11 and a cathode 12, which is particularly a solid oxide fuel cell (SOFC). However, the fuel cell is not limited to the SOFC. In the figure, reference numeral 2 denotes a gas turbine including a turbine 21 and a compressor 22 that are connected to each other by a connecting shaft 23, and a starter / generator 24 that is directly connected to the turbine 21 and the compressor 22. The starter / generator 24 functions as a motor when the gas turbine 2 is started to start the gas turbine 2, while the starter / generator 24 functions as a generator that outputs AC power, for example, after the gas turbine 2 is started. The configuration of the gas turbine 2 is not limited to a single-shaft configuration in which the starter / generator 24 is directly connected to the turbine compressors 21 and 22, and other configurations such as a two-shaft configuration may be employed.

  The compressor 22 of the gas turbine 2 compresses and discharges the introduced outside air, and the exhaust gas passes through a first heat exchanger 31 and a second heat exchanger 32 described later, and the cathode 12 of the SOFC 1. To be supplied.

  The turbine 21 of the gas turbine 2 is driven to rotate by being supplied with combustion gas from a combustor 33 to be described later to drive the compressor 22, and the exhaust of the turbine 21 passes through a turbine exhaust pipe 51. It is sent to the primary side of the first heat exchanger 31.

  The first heat exchanger 31 is interposed between the gas turbine 2 and the SOFC 1. As described above, the turbine exhaust pipe 51 is connected to the primary side of the first heat exchanger 31 and the secondary side thereof is connected to the secondary side. The compressor exhaust pipe 52 connected to the exhaust side of the compressor 22 is connected. Accordingly, the first heat exchanger 31 performs heat exchange between the high-temperature exhaust of the turbine 21 and the exhaust of the compressor 22. Hot air generated by raising the temperature of the exhaust of the compressor 22 is supplied to the SOFC 1 through the air supply pipe 53.

  A reformer 34 is connected to the SOFC 1. A desulfurization device 35 is connected to the reformer 34 through a fuel supply pipe 56. The reformer 34 is supplied from a fuel supply source (not shown) and desulfurized in the desulfurization device 35 (aircraft). In this embodiment, the jet fuel) is reformed. The hydrogen-rich fuel gas generated in this way is supplied to the anode 11 of the SOFC 1 through the fuel gas supply pipe 55. In this embodiment, the reformer 34 is configured to perform steam reforming, and steam necessary for the steam reforming is supplied from a steam generator 41 described later.

  Since the unreacted fuel is contained in the exhaust of the anode 11 in the SOFC 1, the exhaust of the anode 11 is returned to the gas turbine 2. That is, the exhaust side of the anode 11 is connected to the combustor 33 connected to the turbine 21 of the gas turbine 2 as described above. As described above, the gas turbine 2 is driven by supplying the combustion gas obtained by burning the exhaust gas of the anode 11 to the turbine 21.

  A branch pipe 57 branched from a fuel supply pipe 56 that connects the desulfurization device 35 and the reformer 34 to each other via a branch valve 58 is also connected to the combustor 33. The branch valve 58 is switched off so as to supply the desulfurized jet fuel only to the combustor 33 side, only the reformer 34 side, or both the combustor 33 and the reformer 34 under the control of the ECU 6 described later. Change. As will be described in detail later, at least when the power system is started, the combustor 33 is supplied with jet fuel (after desulfurization) supplied from the fuel supply source, not the exhaust of the anode 11. It has become.

  On the other hand, the exhaust of the cathode 12 in the SOFC 1 is sent to the primary side of the second heat exchanger 32 and then supplied to the combustor 33.

  The air supply pipe 53 is connected to the secondary side of the second heat exchanger 32, whereby the second heat exchanger 32 is connected to the exhaust of the cathode 12 and hot air from the first heat exchanger 31. Heat exchange between. As a result, hot air having a higher temperature is supplied to the cathode 12. Such heat recovery improves the efficiency of the power system.

  A branch pipe 59 is branched in the middle of the air supply pipe 53, and the downstream side of the branch officer 59 is connected to the reformer 34. As will be described later, part of hot air from the first heat exchanger 31 is supplied to the reformer 34 through the branch pipe 59 when the power system is started. This is used to raise the temperature of the reformer 34.

  In addition, a water condenser / separator 42 is connected to the primary exhaust section of the first heat exchanger 31. Since the combustion gas combusted by the combustor 33 contains a relatively large amount of moisture, the water condenser / separator 42 performs gas-liquid separation by condensing moisture from the exhaust of the turbine 21. The separated gas is exhausted from the power system and discharged outside the system, while the separated water is sent to the steam generator 41.

  As described above, the steam generator 41 converts the water supplied from the water condenser / separator 42 into steam and supplies it to the reformer 34. Thus, steam necessary for fuel reforming in the reformer 34 is supplied. In this way, by using the exhaust of the turbine 21 for the generation of water vapor, the power system can be a self-supporting system.

  The electric power system (hybrid power generator) is controlled by an ECU (Electric Control Unit) 6 as a control unit. In this embodiment, the ECU 6 controls at least the gas turbine 2 for adjusting the air supply amount to the SOFC 1, the reformer 34 for adjusting the fuel supply amount to the SOFC 1, and the branch valve 58. . The adjustment of the fuel supply amount to the SOFC 1 is not limited to controlling the reformer 34. Further, when the configuration of the power system is a configuration that does not require fuel reforming, the amount of fuel supplied to the SOFC 1 may be adjusted by controlling appropriate means.

  The ECU 6 is also connected to an aircraft data bus 61. As a result, various data on the data bus 61 are input to the ECU 6.

  Next, the control at the time of starting the electric power system by the ECU 6 will be described. First, it is assumed that the temperature of the SOFC 1 is much lower than its operating temperature in the stop state before starting the power system. In this state, when starting the electric power system, the ECU 6 first controls the branch valve 58 and the gas turbine 2 to start the gas turbine 2, whereby jet fuel (after desulfurization) from the fuel supply source is combusted. The starter 24 is driven as well as being supplied to the reference numeral 33 (see the dashed line arrow in the figure). At this time, no fuel is supplied to the reformer 34.

  As a result, the fuel gas from the combustor 33 is supplied to the turbine 21, whereby the gas turbine 2 is started. Since the startup time of the gas turbine 2 is relatively short, the gas turbine 2 is in a steady state at an early stage. In addition, the generator 24 is driven by driving the gas turbine 2 to start the power generation by the generator 24.

  High temperature hot air is generated in the first heat exchanger 31 as the gas turbine 2 is driven. A part of the hot air is supplied to the cathode 12 of the SOFC 1 and a part of the hot air is supplied to the reformer 34 (refer to the dashed line arrow in the figure). As a result, the temperature of the SOFC 1 is raised and the reformer 34 is also raised, so that the temperatures of the SOFC 1 and the reformer 34 can be set to predetermined temperatures at an early stage.

  Thus, for example, if the temperature of the SOFC 1 and the temperature of the reformer 34 rise to the operating temperature or a temperature close thereto based on the detected value of the exhaust temperature sensor 60 that detects the exhaust temperature of the SOFC 1, the ECU 6 branches. By controlling the valve 58, jet fuel is supplied to the reformer 34 (see the solid line arrow in the figure). As a result, the reformed fuel and the hot air are supplied to the SOFC 1, so that power generation in the SOFC 1 is started and DC power is output.

  After the power generation of the SOFC 1 is started, unreacted fuel is contained in the exhaust of the anode 11, so that the exhaust is combusted in the combustor 33 and the generated fuel gas is supplied to the turbine 21 of the gas turbine 2. As a result, the gas turbine 2 is driven. In the steady state of the power system, the supply of jet fuel from the fuel supply source to the combustor 33 may be stopped, or the supply may be continued as necessary.

  With the start of power generation of the SOFC 1, heat exchange in the second heat exchanger 32 is also started by the exhaust heat.

  Note that the supply of hot air to the reformer 34 may be stopped after the operation of the SOFC 1.

  In this way, when the power system is started, the gas turbine 2 having a relatively short start-up time is first started, so that the SOFC 1 and the reformer 34 can be heated using the exhaust heat of the gas turbine 2. it can. As a result, the temperature of the SOFC 1 and the reformer 34 can be raised in a relatively short time to shorten the startup time of the power system. In addition, since power generation is performed by driving the gas turbine 2 before the start of the SOFC 1, power supply by the power system can be performed earlier, and the necessary power in the aircraft can be secured early. it can.

  After the electric power system is in a steady state, the ECU 6 detects various data from the data bus, the exhaust temperature sensor, the hydrogen concentration sensor for detecting the hydrogen concentration in the exhaust of the SOFC 1, and the detection from the pressure sensor 60. Based on the data, the fuel supply amount and / or the air supply amount to the SOFC 1 are controlled by controlling the reformer 34 and the gas turbine 2 according to a control program stored in advance. Thereby, the temperature and pressure in the SOFC 1 are maintained at a temperature and pressure at which power generation efficiency is maximized.

  For example, it is assumed that it is specified that the aircraft is cruising at a high altitude based on the barometric altitude data, the outside air temperature data, the airspeed data obtained from the data bus 61, the operation mode of the aircraft, and the like. At this time, the temperature and pressure of the outside air introduced into the compressor 22 are significantly lower than those on the ground.

  Therefore, the ECU 6 increases the amount of fuel supplied to the SOFC 1 by controlling the reformer 34 and performs feedback control based on detection values of the exhaust temperature sensor, the hydrogen concentration sensor, and the pressure sensor 60. As a result, the amount of unreacted gas in the exhaust of the SOFC 1 increases, and accordingly, the amount of heat supplied to the gas turbine 2 increases and the temperature of hot air after heat exchange in the first heat exchanger 31 increases. . Further, the exhaust pressure of the compressor 22 is increased by the control of the gas turbine 2. Then, as the pressure and temperature of the hot air supplied to the SOFC 1 are increased, the temperature in the SOFC 1 becomes a desired temperature. Thus, the power generation efficiency by the SOFC 1 is increased, and the efficiency of the entire power system at the time of flying can be improved.

  Further, it is assumed that, based on the operation mode of the aircraft obtained from the data bus 61, it is specified that the aircraft is on the ground and its power load is relatively small. At this time, for example, if an amount of fuel that can be rated output is supplied to the SOFC 1, the fuel is wasted.

  Therefore, the ECU 6 controls the reformer 34 so as to reduce the amount of fuel supplied to the SOFC 1 and performs feedback control based on the detection value of the hydrogen concentration sensor 60. As a result, the gas turbine 2 is brought into an idle state, for example. By doing so, energy saving operation corresponding to the electric power load is realized at light load.

  As described above, in the power supply system according to the present embodiment, the ECU 6 determines the fuel supply amount to the SOFC 1 and / or based on the detection values of the exhaust temperature sensor, the hydrogen concentration sensor, and the pressure sensor 60 and various data from the data bus 61. Or, by controlling the air supply amount, the operation of the power system is optimized from various viewpoints such as the viewpoint of the power generation efficiency of SOFC1, the efficiency of the entire power system, and the viewpoint of energy-saving operation corresponding to the power load. can do.

  When the power system of the present invention is configured as a power system mounted on a transport device other than an aircraft or other power system, an SOFC is used by using an appropriate data providing means replacing the data bus 61. The fuel supply amount and / or the air supply amount may be controlled.

  As described above, the present invention enables stable and economical power generation in response to changes in the use environment and operation state in a system including a fuel cell and a gas turbine. This is useful for power systems.

It is a block diagram which shows the structure of the electric power system which concerns on embodiment of this invention.

Explanation of symbols

1 Solid oxide fuel cell (fuel cell)
2 Gas turbine 21 Turbine 22 Compressor 24 Starter / generator (generator)
33 Combustor 34 Reformer 6 Control unit (ECU)

Claims (2)

A gas turbine including a turbine, a compressor, and a generator;
A fuel cell to which the exhaust of the compressor is supplied; and
A hybrid power generation device including fuel supply means for supplying fuel to the fuel cell;
A combustor for combusting the exhaust of the fuel cell and supplying the combustion gas to a turbine of the gas turbine;
A control unit for controlling the fuel supply amount and the air supply amount to the fuel cell by controlling the fuel supply means and the gas turbine;
The hybrid power generator is an auxiliary power unit mounted on an aircraft,
The control unit is connected to a data bus mounted on the aircraft, and controls a fuel supply amount and an air supply amount to the fuel cell based on various data from the data bus,
A heat exchanger interposed between the gas turbine and the fuel cell and performing heat exchange between the exhaust of the turbine and the exhaust of the compressor;
When the control unit specifies that the aircraft is cruising at a high altitude, the amount of unreacted gas in the exhaust of the fuel cell is increased so that the amount of unreacted gas in the exhaust of the fuel cell is larger than that at a steady time other than at the high altitude cruise . increasing the fuel supply amount, to increase the temperature of the air supplied to the fuel cell to a predetermined temperature Rutotomoni, the pressure of the air supplied to the fuel cell through the control of the gas turbine, other than the altitude cruising An electric power system that increases more than usual .
The power system according to claim 1 ,
The control unit sends the fuel cell to the fuel cell when the power load on the aircraft is relatively small, based on at least the data related to the hydrogen concentration in the exhaust of the fuel cell and the operation mode data of the aircraft from the data bus. A power system that reduces at least the fuel supply.

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