JP2017139850A - Power supply system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a power supply system which uses renewable energy power generation equipment and an engine power generator, and which can be downsized and furthermore allows for reduction in an amount of use of engine fuel.SOLUTION: The power supply system is provided that supplies power using both of power generation equipment R converting renewable energy into electric energy and an engine power generator 7. A part of the electric energy obtained by the power generation equipment R is supplied to an electrolysis device 6 to produce hydrogen and oxygen, the produced hydrogen and oxygen are directly supplied to the engine power generator 7, which generates power using at least either the hydrogen or engine fuel as fuel. An amount of power supplied from a power distribution device to the electrolysis device is controlled in such a way that a load fluctuation ratio of the engine power generator falls within a predetermined range.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a system for generating stable power using a renewable energy power generator, an engine generator, and an electrolyzer.

Due to the problem of CO ₂ reduction and the problem of depletion of underground resources, power generation using renewable energy such as sunlight and wind power is being actively promoted. However, since renewable energy is greatly affected by the natural environment, the amount of power generated by the energy changes greatly, and system power becomes unstable when introduced on a large scale. Therefore, it is necessary to prepare an energy storage system separately. For example, as in Patent Document 1, a system has been proposed in which hydrogen is produced by an electrolysis apparatus using a part of power generation by renewable energy, and the produced hydrogen is combined with an aromatic compound and stored as a hydride.

JP 2014-84792

  By the way, in the system of patent document 1, in order to convert and store a part of electric power generated by renewable energy into hydrogen energy, a hydrogenation device, a hydride tank, a dehydride tank, a reactor, etc. An energy storage device is required, and there are problems in terms of system enlargement and equipment costs.

On the other hand, in an electric power supply system using a renewable energy power generation device and an engine generator, there are the following problems when the energy storage device is eliminated to simplify the system. Engine generators need to be able to meet demand even when the generation of renewable energy is zero. Therefore, when a part of the demand power can be supplied by the renewable energy power generation apparatus, the output is lowered to follow the operation. However, since the efficiency of the engine generator is reduced at low output, the problem is that the consumption of engine fuel increases. Also, from the viewpoint of stable power supply, it is necessary to maintain the engine generator output at a constant value or higher and to maintain the engine generator load fluctuation rate within a predetermined range. is there. Therefore, the amount of engine fuel required to maintain the power generation state of the engine generator is required, and there are problems such as an increase in the size of the fuel tank and CO ₂ emission due to combustion of hydrocarbon fuel. In addition, even if the renewable energy power generation device can supply more power than the demand power, the engine generator cannot be stopped, so the surplus power that can be generated with renewable energy cannot be used effectively, exceeding a certain level. The amount of fuel used for the engine generator cannot be reduced.

  The present invention relates to a power supply system using a renewable energy power generation apparatus, an engine generator, and an electrolysis apparatus, and a power supply system that can reduce the amount of engine fuel used and a control method thereof in addition to downsizing the system. The purpose is to provide.

  An electric power supply system according to the present invention is an electric power supply system that supplies electric power using both power generation by renewable energy and power generation by an engine generator, and a power generation device that converts the renewable energy into electric energy; A power distribution device that supplies part of the power obtained by the power generation device to the electrolysis device, an electrolysis device that produces hydrogen and oxygen using the power supplied from the power distribution device, and the electrolysis First supply means for supplying hydrogen and oxygen from the apparatus to the engine generator, a fuel tank for storing engine fuel to be supplied to the engine generator, and supplying engine fuel from the fuel tank to the engine generator A second supply means, and a control unit for electronically controlling the power supply system, wherein the engine generator is hydrogen or energy. Power is generated using at least one of gin fuel as fuel, and the control unit controls the amount of power supplied from the power distribution device to the electrolyzer so that a load fluctuation rate of the engine generator falls within a predetermined range. It is characterized by.

  According to the present invention, in a power supply system using a renewable energy power generation device and an engine generator, it is possible to reduce the size of the system, increase the amount of power generated by the renewable energy power generation device, and reduce the amount of engine fuel used.

BRIEF DESCRIPTION OF THE DRAWINGS Configuration explanatory drawing of the electric power supply system which concerns on embodiment of this invention. It is the figure which showed an example of the relationship of the renewable energy electric power generation amount with respect to supplied electric power, and an engine electric power generation amount. It is a figure which shows an example of the consumption of the fossil fuel by renewable energy introduction. It is the elements on larger scale which show typically the cylinder head neighborhood of the diesel engine used for the engine generator which constitutes the electric power supply system concerning the embodiment of the present invention. It is an example of the partial enlarged view which shows typically the cylinder head vicinity of the spark ignition engine used for the engine generator which comprises the electric power supply system which concerns on embodiment of this invention. It is an example of the partial enlarged view which shows typically the cylinder head vicinity of the spark ignition engine used for the engine generator which comprises the electric power supply system which concerns on embodiment of this invention. It is a control flowchart of the operation mode of the electric power supply system which concerns on embodiment of this invention. It is a control flowchart of the operation mode of the electric power supply system which concerns on embodiment of this invention. It is a control flowchart of the operation mode of the electric power supply system which concerns on embodiment of this invention. It is the figure which showed an example of the relationship of the renewable energy electric power generation amount with respect to the case where the electric power generation amount by renewable energy decreased rapidly, and an engine electric power generation amount. It is the figure which showed an example of the relationship between the renewable energy electric power generation amount and engine electric power generation amount with respect to the case where the grid power demand increases rapidly. BRIEF DESCRIPTION OF THE DRAWINGS Configuration explanatory drawing of the electric power supply system which concerns on embodiment of this invention. The structure explanatory view of the water supply line of the power supply system concerning the embodiment of the present invention. Structure explanatory drawing of the example of a change of the water supply line of the electric power supply system which concerns on embodiment of this invention. Structure explanatory drawing of the example of a change of the water supply line of the electric power supply system which concerns on embodiment of this invention. It is the elements on larger scale which show typically the cylinder head neighborhood of the diesel engine used for the engine generator which constitutes the electric power supply system concerning the embodiment of the present invention. It is the elements on larger scale which show typically the cylinder head neighborhood of the diesel engine used for the engine generator which constitutes the electric power supply system concerning the embodiment of the present invention. It is an example of the partial enlarged view which shows typically the cylinder head vicinity of the spark ignition engine used for the engine generator which comprises the electric power supply system which concerns on embodiment of this invention. It is an example of the partial enlarged view which shows typically the cylinder head vicinity of the spark ignition engine used for the engine generator which comprises the electric power supply system which concerns on embodiment of this invention. The structure explanatory view at the time of using a turbine engine as an engine generator of an electric power supply system concerning an embodiment of the present invention. It is the figure which showed the compression energy with respect to the supply fuel calorie | heat amount at the time of supplying hydrogen derived from renewable energy to a turbine engine. It is the figure which showed the influence which the presence or absence of water supply has on the turbine engine adiabatic flame temperature. It is the figure which showed the influence which high temperature high pressure water supply to a turbine engine has on power conversion efficiency. It is the figure which showed the relationship between the water vapor | steam density | concentration in exhaust gas, and the hydrogen supply ratio derived from renewable energy. It is the figure which showed the outside temperature and the density | concentration in gas.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings as appropriate.

[First embodiment]
The power supply system according to the present embodiment is a system that supplies power using both a power generation device R that converts renewable energy into electric energy and power generation by the engine generator 7, and is obtained by the power generation device R. Hydrogen and oxygen are produced by supplying a part of the electrical energy to the electrolyzer 6, and the produced hydrogen and oxygen are directly supplied to the engine generator 7, and at least one of hydrogen or engine fuel is used as fuel for engine power generation It is characterized by generating electricity with a machine. That is, a part of the electric power derived from the fluctuating renewable energy is supplied to the electrolyzer, and hydrogen and oxygen generated by the electrolysis are used as assist fuel for the engine generator. By determining the amount of power supplied to the electrolyzer and the amount of power generated by the engine generator with reference to the power demand and the amount of renewable energy generated, the amount of hydrogen generated and the amount of oxygen to determine the engine fuel amount Stable supply and reduction of engine fuel.

  Hereinafter, the configuration of the power supply system, and the operation and control method of the system will be described.

<System configuration>
FIG. 1 is a configuration explanatory diagram of a power supply system according to an embodiment of the present invention. As shown in FIG. 1, the power supply system S according to the present embodiment includes a power generation device R based on renewable energy, a renewable energy power generation amount measuring device 104 that measures the amount of renewable energy power generation, and a system power demand. A power demand measuring device 109 for measuring, a power distribution device 5 for distributing and supplying power generated by the power generation device R to the electrolysis device 5 and the system 10, an electrolysis device 6 for generating hydrogen and oxygen, and engine fuel An engine generator 7 that generates electric power by burning hydrogen, a fuel tank 8 that stores engine fuel to be supplied to the engine generator 7, and a supply that supplies hydrogen, oxygen, and engine fuel to the engine generator The apparatus 101, 102, 103, a power adjustment device 9 that supplies power generated by the engine generator 7 to the system, and a control unit 11 are configured. In FIG. 1, the practice represents electrical wiring, the double line represents hydrogen, oxygen and engine fuel lines, and the broken line represents signal lines used for measurement or control.

  In the power supply system of this embodiment, the engine generator is based on the demand power (Wd) measured by the demand power measuring device 109 and the power generation amount (Wr) of the power generator R measured by the renewable energy power generation amount measuring device 104. Power generation amount (Weg) and electric power amount (Wel) to be supplied to the electrolyzer are determined, and supply devices 101, 102, and 103 for supplying hydrogen, oxygen, and engine fuel using the electric distribution device 5 and the control unit 11 are determined. Be controlled. Thereby, electric power is stably supplied from the power generator R and the engine generator 7 with respect to the electric power demand.

  A detailed control method will be described later together with the description of the control unit.

  Energy for supplying surplus power that can be generated with renewable energy to the system by supplying hydrogen and oxygen generated by the electrolyzer 6 to the engine generator 7 and using them as assist fuel for engine fuel Can be used effectively. Further, by supplying hydrogen and oxygen as assist fuel to the engine generator, it is possible to improve the power generation efficiency of the engine generator 7 and reduce the amount of engine fuel used. At this time, depending on the amount of hydrogen produced by the electrolyzer 6, it is also possible to generate electricity using only hydrogen without using engine fuel. The amount of power generated by the engine generator (Weg) and the amount of power distributed and supplied from the power generator R to the electrolyzer 6 take into account the conversion efficiency of the electrolyzer 6, the power generator efficiency of the engine generator 7 and the load fluctuation rate. It is desirable to decide. Rather than supplying all the power that can be generated by the power generator R to the system, the amount of power generated by the engine generator is increased and a part of the power of the power generator R is supplied to the electrolyzer 6 to generate hydrogen. This is because the overall system efficiency becomes higher when oxygen and oxygen are supplied to the engine generator as assist fuel, and the amount of engine fuel used may be reduced, and the power demand can be stabilized. For example, when the amount of electric power in the power generator R is large and the output of the engine generator 7 is small, the efficiency of the entire system is reduced due to a decrease in the power generation efficiency of the engine generator 7. Therefore, when the amount of renewable energy with respect to the amount of power demand is greater than or equal to the predetermined amount, the amount of power supplied to the electrolyzer by the power distribution device is reduced according to the increase in the amount of renewable energy without reducing the output of the engine generator. It is preferable to increase.

  As described above, in the power supply system of the present embodiment, fluctuations in the amount of power generated by the renewable energy power generation device R can be absorbed as shown in FIG. 2 without using an energy storage device, thereby enabling stable power supply. Further, in the system configuration that does not use the conventional energy storage device as shown in FIG. 3, the engine generator output cannot be reduced below a certain level, so the effect of reducing the engine fuel is small. It is also possible to stably supply power with% renewable energy, and the amount of fuel used by the engine generator can be reduced. In addition, this configuration eliminates the need for energy storage devices such as power storage devices that store fluctuations and surpluses from renewable energy power generation devices, and hydrogen storage devices such as hydrogen storage high-pressure tanks and organic hydrides. Simplification can be achieved.

<Renewable energy equipment>
The renewable energy power generation apparatus R is configured by a power generation apparatus using renewable energy such as a solar power generation apparatus 1 or a wind power generation apparatus 2. In addition, it will not be limited if it is a power generator using renewable energy. The power generation device includes a current control device capable of adjusting each power amount and supplying it to the system. For example, PCS3 in the case of the solar power generation device 1 and power conversion device 4 in the wind power generation device (AC / DC / AC, etc.) that can control the voltage, frequency, etc. and can supply power to the system It is not limited.

<Renewable energy power generation measuring device>
The renewable energy power generation amount measuring device 104 is not particularly limited as long as it can measure the power generation amount of the renewable energy generator. A device that predicts the amount of power generation using a known device such as a solar radiation meter or an anemometer may be used. Alternatively, a method for predicting the amount of power generation using prediction information such as weather forecasts by weather satellites may be used.

<Power demand measuring device>
The power demand measuring device 109 is not particularly limited as long as it is a device that can measure power demand during system operation. Alternatively, a method for predicting power demand during system operation using past power demand data may be used.

<Power distribution device>
Part of the electric power generated by the renewable energy power generator is supplied to the electrolyzer 6 through the power distributor 5. The power distribution device 5 is not particularly limited as long as each power value can be supplied to the electrolyzer 6. However, the amount of power supplied to the electrolysis is determined by the control unit 11.

<Electrolysis device>
The specific configuration of the electrolyzer 6 is not particularly limited. For example, the electrolyzer 6 is configured to electrolyze water using an electrolyte solution, an electrolyte, and a reaction promoting electrode catalyst provided so as to sandwich the electrolyte. Hydrogen and oxygen are generated.

  The electrolyzer 6 is preferably an electrolyzer using solid polymer water electrolysis or alkaline water electrolysis that can be electrolyzed at a relatively low temperature and can be started in a short time. The electrolysis apparatus based on solid polymer water electrolysis uses a polymer electrolyte having proton conductivity as a partition and an electrolyte to electrolyze pure water, and can efficiently produce high purity hydrogen. . An electrolysis apparatus based on alkaline water electrolysis produces hydrogen by electrolyzing an alkaline aqueous solution using an alkaline compound as an electrolyte when dissolved in water such as potassium hydroxide.

<Fuel supply device>
Hydrogen and oxygen generated from the electrolysis device 6 are supplied to the engine generator 7 via the hydrogen fuel supply device 101 and the oxygen supply device 102. Further, engine fuel is supplied from the fuel tank 8 to the engine generator 7 via the fuel supply device 103. Known supply means such as an injector is applied to the supply devices 101, 102, and 103, and the supply amount, supply pressure, and the like are controlled by the control unit 7. When the supply pressure of hydrogen and oxygen is low, pressurization may be performed with a compressor or the like.

<Engine generator>
A known engine such as a diesel engine, a spark ignition engine, or a gas turbine is applied to the engine generator. The engine generator 7 is configured to generate electric power by burning hydrogen and engine fuel. The number of engine generators 7 is not particularly limited and may be one or more. The electric power generated by the engine generator 7 is adjusted in voltage, frequency and the like by the power converter 9 and supplied to the system. Oxygen and hydrogen generated by electrolysis are supplied to the engine generator. The exhaust heat from the engine generator can be used as heat energy supplied inside or outside the system. The heat supply destination is not particularly limited as long as the engine exhaust heat can be used. For example, the electric power may be supplied to the electrolyzer 6 for use in raising the temperature of the electrolyzer, heating, or the like, or electric power may be supplied by thermoelectric conversion using engine exhaust heat.

<Diesel engine>
FIG. 4 is a partially enlarged view schematically showing the vicinity of a cylinder head when a diesel engine is used as an engine of an engine generator constituting the power supply system according to the present embodiment. The diesel engine includes a piston 11 that reciprocates in a cylinder, and an intake pipe 13 and an exhaust pipe 14 are connected to a combustion chamber 12 in the cylinder. A hydrogen supply device 101 for supplying hydrogen and oxygen generated by the electrolyzer 6 and an oxygen supply device 102 are attached to the intake pipe 13. Hydrogen and oxygen are supplied to the engine together with intake air from the hydrogen supply device 101 and the oxygen supply device 102. Since hydrogen is manufactured based on renewable energy, the introduction ratio of renewable energy can be increased by using hydrogen. In addition, the supply of hydrogen makes it possible to reduce the consumption of main fuel (engine fuel) and to reduce the amount of soot emission by improving the combustibility. In addition, the oxygen concentration in the engine intake gas can be increased by supplying oxygen to the engine, so the engine output can be increased, the engine operating range can be expanded, and the engine can be downsized. It becomes. Further, since the combustion efficiency can be improved by improving the oxygen concentration in the working gas, the thermal efficiency can be improved. This makes it possible to reduce engine fuel consumption. Further, a fuel supply device 103 for directly supplying the engine fuel of the fuel tank 8 to the engine is attached.

  The supply of oxygen improves the combustibility of the engine fuel and burns quickly. In addition, the ignition timing of the engine fuel is delayed by the supply of hydrogen. For these reasons, a control unit may be provided that controls the engine fuel injection timing and the supercharging device with reference to the measurement value from the hydrogen flow meter 105 or the oxygen flow meter 106 or both. This allows stable combustion when hydrogen or oxygen or both are supplied. The injection timing and the command value for supercharging control are determined to be arbitrary values based on the specifications of the engine generator and the flow rate of hydrogen or oxygen.

<Spark engine>
FIG. 5 is a partially enlarged view schematically showing the vicinity of a cylinder head when a spark ignition engine is used as the engine of the engine generator constituting the power supply system according to the present embodiment. The spark ignition engine includes a piston 21 that reciprocates in a cylinder, and an intake pipe 23, an exhaust pipe 24, and an ignition plug 25 are connected to a combustion chamber 22 in the cylinder. A hydrogen supply device 101 for supplying hydrogen and oxygen generated by the electrolyzer 6 and an oxygen supply device 102 are attached to the intake pipe 23. Hydrogen and oxygen are supplied to the engine together with intake air from the hydrogen supply device 101 and the oxygen supply device 102. Since hydrogen is manufactured based on renewable energy, the introduction ratio of renewable energy can be increased by using hydrogen. Further, since hydrogen has a higher combustion speed than hydrocarbon fuels generally used as engine fuels and a combustion range is larger than hydrocarbon fuels, rapid combustion and lean combustion are possible. Furthermore, since the combustibility is higher than that of hydrocarbon fuel, the combustion efficiency can be improved. As a result, the engine thermal efficiency is improved and the consumption of engine fuel can be reduced. Further, since oxygen concentration in the engine intake gas can be increased by supplying oxygen to the engine, the engine output can be increased, and the engine operating range can be expanded and the engine thermal efficiency can be improved. As a result, since it is possible to suppress a decrease in thermal efficiency due to operation at a low load, it is possible to reduce engine fuel consumption even at a low load.

  Further, an engine fuel supply device 103 for directly supplying the engine fuel of the fuel tank 8 to the engine is attached. As shown in FIG. 6, the engine fuel supply device 103 may have a structure in which it is directly injected into the engine combustion chamber.

  The supply of oxygen improves the combustibility of the engine fuel and burns quickly. In addition, by supplying hydrogen, rapid combustion occurs, and the ignition delay of engine fuel is reduced. For these reasons, a control unit that controls engine fuel injection timing, ignition timing by the ignition plug, intake valve and exhaust valve operation timing, etc., with reference to the measured values from the hydrogen flow meter 105 and / or the oxygen flow meter 106 May be provided. This allows stable combustion when hydrogen or oxygen or both are supplied. The command values for the engine fuel injection timing, the ignition timing by the spark plug, and the valve operation timing are determined arbitrarily according to the engine specifications.

<Engine fuel>
Known fuels such as gasoline, light oil, heavy oil, natural gas, bioethanol, and biodiesel are applied to the engine fuel.

<Power adjustment device>
The power adjustment device 9 is not particularly limited as long as it is a device that can adjust voltage, frequency, and the like in order to supply power generated by the engine generator to the system. Specifically, a known device such as an AC / AC converter can be used.

<System>
The grid 10 is not limited to the power grid of an electric power company, and may be an independent power grid such as an island or a large-scale factory, and is not particularly limited.

<Control unit>
Next, the control unit 11 that electronically controls the power supply system S will be described.

  The control unit 11 includes a CPU, a ROM, a RAM, various interfaces, an electronic circuit, and the like, and comprehensively controls the power supply system S according to a program stored therein. And the control part 11 controls the electric power distribution apparatus shown in FIG. 1, various supply apparatuses, etc. according to the procedure mentioned later. The procedure executed by the control unit 11 will be described in detail later together with the operation description of the power supply system.

<Operation of power supply system>
Next, an example of the operation of the power supply system according to this embodiment will be described.

  FIG. 7 is a flowchart showing a procedure executed by the control unit in the operation mode of the present system.

  The control unit 11 measures the system demand power Wd (step S1). Thereafter, the renewable energy power generation amount measuring device 104 measures the renewable energy power generation amount Wr (step S2). Thereafter, the amount of electricity Wel supplied to the electrolyzer is determined by the following equation (step S3).

Wel = Wr − Wrd
However, if the above expression becomes negative, Wel is 0.
Wrd is the amount of renewable energy that can be connected to the grid
Wrd is determined by the following formula from the power demand Wd and the grid connection possible ratio α.

Wrd / Wd <α
The system connectable ratio α is determined in advance according to the size of the system and the specifications of the renewable energy generator and the engine generator.

  The power generation amount Weg by the engine generator is determined from the following equation (step S4).

Weg = Wd −Wrd
The power generation amount Weg of the engine generator has a lower limit of Wegmin due to the performance of the engine generator and stabilization of the system power. Wegmin is determined by the system configuration, taking into account the specifications of the engine generator and stable power demand.
Further, it is determined whether or not the load fluctuation of the engine generator is within the range of the allowable load fluctuation rate (step S5).
X = ΔWeg / Δt
A <X <B
Here, t is time. A is an allowable load reduction rate, and B is an allowable load fluctuation increase rate.

When the load fluctuation rate X is out of the allowable load fluctuation rate range, the following control is performed so as to be within the allowable range. If the load fluctuation rate X is less than the allowable load reduction rate A, Wel is increased. On the other hand, when the load fluctuation rate X is larger than the allowable load increase rate B, Wel is reduced (step S101).
Thereafter, the process returns to step S4, and the power generation amount Weg of the engine generator is determined again.
When the load fluctuation rate of the engine generator is within a predetermined range, a control signal is sent to the power distribution device 5 (step S6).

  Thereafter, the amount of hydrogen produced by the electrolyzer 6 is measured by the hydrogen flow meter 105, and the amount of oxygen is measured by the oxygen flow meter 106 (step S7). Then, the hydrogen supply flow rate and the oxygen supply flow rate are determined, and control signals are sent to the hydrogen supply device 101 and the oxygen supply device 102 (step S8). Thereafter, the supply amount of engine fuel is determined based on the hydrogen supply flow rate and the oxygen supply flow rate, and a control signal is sent to the engine fuel supply device 103 (step S9). Thereafter, it is determined whether the power supply amount is the target system power supply amount. If the power supply amount is different from the target system power supply amount, the process returns to step S9 to perform feedback control (step S10).

  By such operation control, even when a change in renewable energy occurs, the engine generator can be operated at a load fluctuation rate within a predetermined range, and a stable power supply can be achieved. Moreover, the electric power derived from surplus renewable energy can be directly utilized without using a storage device.

  As described above, according to the power supply system of the present embodiment, a part of the power generated by the renewable energy power generation is used for electrolysis, hydrogen and oxygen are generated, and hydrogen or engine fuel is supplied to the engine generator. Thus, power can be supplied stably. Further, by supplying hydrogen and oxygen to the engine generator, it is possible to reduce the amount of fossil fuel used as engine fuel. Further, since the energy storage device is not necessary, the cost of the entire system can be reduced.

[Second Embodiment]
The power supply system according to the present embodiment is a system that supplies power using both a power generation device R that converts renewable energy into electric energy and power generation by the engine generator 7, and is obtained by the power generation device R. Hydrogen and oxygen are produced by supplying a part of the electrical energy to the electrolyzer 6, and the produced hydrogen and oxygen are directly supplied to the engine generator 7, and at least one of hydrogen or engine fuel is used as fuel for engine power generation It is characterized by generating electricity with a machine. The description of the same configuration as that of the first embodiment is omitted.

<System configuration>
The control unit measures or predicts the rate of change Y of the amount of electric power for demand and the rate of change Z of the amount of power generated by renewable energy, and performs system control. Other configurations are the same as those in the first embodiment. FIG. 8 is a flowchart showing a procedure executed by the control unit in the operation mode of the present system.

  Steps 1 to 10 are the same as those in the first embodiment. Thereafter, when the engine generator generates electric power Weg at the lower limit value Wegmin and supplies hydrogen to the engine generator, the control flow is shifted to the Wegmin operation mode (step S102). FIG. 9 shows a control flow in the Wegmin operation mode.

The control unit 11 measures the system demand power Wd (step S11). Thereafter, the renewable energy power generation amount Wr is measured by the renewable energy power generation amount measuring device 104 (step S12). Thereafter, the rate of change Y of the amount of electric power for demand and the rate of change Z of the amount of power generated by renewable energy are calculated by the following equations. (Step S13)
Y = ΔWd / Δt
Z = ΔWr / Δt
Here, t is time. Thereafter, it is determined whether the rate of change Y of the amount of power for demand is greater than the allowable rate of change C of the power for demand or the rate of change Z of the amount of power generated by renewable energy is smaller than the rate of change D of the amount of power generated (step S14). The allowable change rate C of power for demand and the allowable change rate D of the amount of power generation are determined in advance according to the size of the system and the specifications of the renewable energy generator and the engine generator. If they are different, the process proceeds to step 3 in FIG. If it is correct, the engine generator power generation amount Weg is determined. However, Weg is increased at the allowable load fluctuation rate B of the engine generator (step S15). Thereafter, the amount of electricity Wel supplied to the electrolyzer is determined by the following equation (step S16).
Wel = Wd −Weg
Thereafter, a control signal is sent to the power distribution device 5 (step S17).

  Thereafter, the amount of hydrogen produced by the electrolyzer 6 is measured by the hydrogen flow meter 105, and the amount of oxygen is measured by the oxygen flow meter 106 (step S18). Then, the hydrogen supply flow rate and the oxygen supply flow rate are determined, and control signals are sent to the hydrogen supply device 101 and the oxygen supply device 102 (step S19). Thereafter, the supply amount of engine fuel is determined based on the hydrogen supply flow rate and the oxygen supply flow rate, and a control signal is sent to the engine fuel supply device 103 (step S20). Thereafter, it is determined whether the power supply amount is the target system power supply amount. If the power supply amount is different from the target system power supply amount, the process returns to step S20 to execute feedback control (step S21).

  With such operation control, even when sudden fluctuations in grid power consumption and power renewable energy occur, the load fluctuation rate of the engine generator can be kept within a predetermined range, enabling stable power supply. Become. In particular, stable operation can be performed within the load fluctuation rate of the engine even when the amount of power generated by renewable energy rapidly decreases as shown in FIG. 10 or when the grid demand power shown in FIG. 11 rapidly increases. As a result, even when the hydrogen generated by the electrolyzer is used as the fuel for the engine generator and the operation is performed at the lower output limit of the engine generator, the operation can be performed within the load fluctuation tolerance. As a result, more electric power derived from renewable energy can be used than before, and the amount of engine fuel used can be reduced.

[Third embodiment]
The power supply system according to the present embodiment is a system that supplies power using both a power generation device R that converts renewable energy into electric energy and power generation by the engine generator 7, and is obtained by the power generation device R. Hydrogen and oxygen are produced by supplying a part of the electric energy to the electrolyzer 6, the produced hydrogen and oxygen are directly supplied to the engine generator 7, and the hydrogen produced by the electrolyzer is temporarily supplied It has a buffer tank 301 for storage, valves 201, 202, 203 for controlling the hydrogen flow rate in the hydrogen line, and pressure gauges in the hydrogen line and oxygen line, and engine generator using at least one of hydrogen or engine fuel as fuel It is characterized by generating electricity at

  The description of the same configuration as the first or second embodiment is omitted.

<System configuration>
FIG. 12 shows another configuration example of the power supply system S. A buffer tank 301 that can temporarily store hydrogen generated from the electrolyzer 6, a valve 201, 202, 203 in a hydrogen line, and a control unit that controls the valve 201, 202, 203 are configured. Other configurations are the same as those in the first embodiment or the second embodiment.

  It has a buffer tank 301 that can temporarily store the hydrogen generated in the electrolyzer 6, and controls the operation of valves 201, 202, and 203 based on the amount of hydrogen supplied to the engine generator from the hydrogen flow meter 105 and the hydrogen supply device 101. decide. For example, when the entire amount of hydrogen generated from the electrolyzer 6 is supplied from the hydrogen fuel supply device to the engine generator, the valve 203 is opened and the valves 201 and 202 are closed. On the other hand, when the amount of hydrogen generated from the electrolyzer 6 exceeds the amount of hydrogen that can be supplied from the hydrogen fuel supply device to the engine generator, the valve 201 and the valve 203 are opened, and the valve 202 is closed. When the amount of hydrogen generated from the electrolyzer 6 is less than the amount of hydrogen that can be supplied from the hydrogen fuel supply device to the engine generator, the valve 202 and the valve 203 are opened, and the valve 201 is closed. Thereby, since the hydrogen pressure supplied to the hydrogen supply device can be maintained at a predetermined pressure, the amount of hydrogen supplied from the hydrogen supply device can be stabilized. Further, the load fluctuation rate of the engine generator can be reduced by using the hydrogen in the buffer tank for the steep fluctuation of the power generation amount due to the power demand and the renewable energy of the system. In addition, since a sudden change in the amount of hydrogen produced by the electrolyzer can be absorbed by providing a buffer tank, the change in the hydrogen state in the fuel supplied to the engine generator can be reduced, so the change in the combustion state of the engine generator Stable combustion is possible by suppressing Further, when the pressure is measured by the pressure gauges 110 and 111 and the pressure of the hydrogen line is high, the valve 201 and the valve 203 are opened, and the valve 202 is closed. On the other hand, when the pressure of the hydrogen line is lower than that of the oxygen line, 202 and valve 203 are opened, and valve 201 is closed. As a result, the pressure difference between the hydrogen line and the oxygen line can be kept within a certain range, so that the membrane in the electrolyzer can be prevented from being broken.

  The size of the buffer tank is determined arbitrarily according to the specifications of the electrolyzer 6 and the engine generator 7. The material is not limited, and any material that can store hydrogen gas may be used. The valves 201, 202 and 203 are not particularly limited as long as they can control the opening and closing of the hydrogen line, and known valves are used. For example, a stop valve that can control only the opening and closing of the line, a needle valve that can adjust the opening, and the like are used.

[Fourth embodiment]
The power supply system according to the present embodiment is a system that supplies power using both a power generation device R that converts renewable energy into electric energy and power generation by the engine generator 7, and is obtained by the power generation device R. Hydrogen and oxygen are produced by supplying a part of the electrical energy to the electrolyzer 6, and the produced hydrogen and oxygen are directly supplied to the engine generator 7, and at least one of hydrogen or engine fuel is used as fuel for engine power generation The engine exhaust pipe is equipped with a heat exchanger, the steam in the exhaust gas is recovered, the recovered water is temporarily stored in a tank, and the recovered water is stored in the electrolyzer 6 and the engine generator 7 It is characterized by performing a water circulation cycle by supplying to both or one of them.

  The description of the same configuration as that of the first, second, or third embodiment is omitted.

<System configuration (modification)>
FIG. 13 shows another configuration diagram of the engine generator and the electrolyzer of the present embodiment. A heat exchanger 401 in the engine exhaust pipe, a water tank that cools the exhaust gas of the engine generator by the heat exchanger and stores water recovered from the water vapor in the exhaust gas, an electrolyzer and engine generator for the recovered water A water supply device for supplying water is provided. The recovered water is supplied to the electrolyzer and / or the engine generator. With this configuration, since the water supplied to the electrolyzer can be replenished with water collected from the exhaust gas, the amount of water supplied to the electrolyzer from the outside can be reduced. As a result, surplus electricity can be supplied to the electrolyzer even in areas where it is difficult to replenish water from the outside, and surplus power can be generated by using hydrogen generated from the electrolyzer. The engine fuel supplied to the engine generator can be reduced. Further, by supplying water to the engine generator, the combustion temperature can be lowered, and the NOx emission from the engine generator is reduced. In gasoline engines and diesel engines, the cooling loss is reduced by lowering the combustion temperature, so that the thermal efficiency is improved. As a result, the consumption of engine fuel can be reduced, and the amount of CO2 emission can be reduced.

  Further, as shown in FIG. 14, the water supplied from the water tank to the electrolyzer and the engine generator is passed through a heat exchanger 405 to be heated water or steam, and the water supply devices 403 and 404 are connected to the electrolyzer. You may supply to one or both of an engine generator. By setting it as such a structure, the water supplied to an electrolyzer is heated and controlled to predetermined temperature. By heating water, the overvoltage of the electrolyzer can be reduced, and the conversion efficiency of electricity from the electrolyzer to hydrogen can be increased. Alternatively, as shown in FIG. 15, the water is supplied to the cooling water line of the engine generator from the water tank and used for adjusting the cooling water temperature of the engine generator, and the heated water is electrolyzed by the water supply devices 403 and 404. And one or both of the generator and the engine generator. By setting it as such a structure, the water supplied to an electrolyzer is heated and controlled to predetermined temperature. By heating water, the overvoltage of the electrolyzer can be reduced, and the conversion efficiency of electricity from the electrolyzer to hydrogen can be increased. In addition, a cooling device for cooling the engine cooling water to a predetermined temperature is not required, and the water is heated by the thermal energy of the engine cooling water, so that the cooling loss of the engine generator can be recovered, and the system efficiency Can be improved.

  The water tank is not limited in material and shape, and may be any container that can store water. The size of the water tank is determined arbitrarily depending on the specifications of the engine generator and the electrolyzer.

  There is no restriction | limiting in particular in the structure in a heat exchanger, A well-known heat exchanger is used.

  The configuration of the water supply device is not particularly limited, and may be configured to be configured by a pump and continuously supplied to the engine and the electrolysis device, or to include a pump and a valve or an injector so as to control the flow rate. As shown in FIGS. 16 to 9, water, heated water, or steam supplied from the water supply device 404 to the engine may be supplied to the intake pipe of the engine or supplied directly to the combustion chamber.

[Fifth embodiment]
<Configuration when using a gas turbine as an engine generator>
The configuration when the turbine system is utilized is shown in FIG. Hydrogen generated from the electrolyzer is supplied to the combustor along with the engine fuel, for example, natural gas, through the flow regulator (V3). Natural gas is supplied to the combustor through a flow regulator (V4). Oxygen generated by the electrolyzer is supplied to the compressor together with air via the flow regulator (V5). Air is supplied to the compressor via the flow regulator (V7).
By adopting such a configuration, it is only necessary to supply a predetermined amount of oxygen to be supplied to the combustor. Therefore, it is possible to reduce the flow rate of gas compressed by the compressor, and to reduce the compression power of the compressor. As a result, the power conversion efficiency of the system is improved.
The inside of the oxygen pipe is measured by a pressure gauge (P1), and when P1 exceeds a predetermined value, it is controlled to be released to the atmosphere by V6. As a result, the pressure difference between the hydrogen side and the oxygen side of the electrolyzer can be kept within a certain range, and the film and the like in the electrolyzer can be prevented from being broken.

  High-temperature and high-pressure steam is supplied to the air compressed by the compressor via the flow rate regulator (V2). As a result, the combustion temperature in the combustor is adjusted to a predetermined range (FIG. 22), and the power conversion efficiency of the turbine can be increased because high enthalpy steam is supplied. (FIG. 23) Although the steam may be supplied to the combustor after being mixed with the air after the compressor, the steam may be supplied directly to the combustor.

  With this configuration, the combustor is supplied with air, hydrogen generated from the electrolysis tank, oxygen, engine fuel, and water vapor independently, and the temperature of the combustor is controlled. The combustion gas temperature supplied to the turbine can be controlled.

  There is a limit to the heat-resistant temperature of the turbine, and the latest is up to 1600 ° C. On the other hand, the higher the inlet pressure and temperature of the turbine, the higher the power conversion efficiency of the turbine. That is, with such a configuration, the turbine temperature can be controlled within a predetermined range, and the durability and power conversion efficiency of the turbine system can be improved. More specifically, in this system, the amount of hydrogen and oxygen generated from the electrolyzer changes because the amount of power supplied to the electrolyzer varies depending on the amount of power demanded and the amount of power generated by renewable energy. However, it is possible to control the amounts of engine fuel, oxygen, water vapor, and air in accordance with the change in hydrogen, and supply constant power or power with a relatively low fluctuation period to the system.

  Next, the water circulation cycle will be described. After generating power in the turbine, gas containing water vapor is discharged from the turbine. Heat exchanger 1 and heat exchanger 2 are installed in the exhaust pipe of the turbine, and when the exhaust gas is cooled, water vapor is condensed and collected in the water tank. The heat exchanger 1 is a heat exchanger that heats the exhaust gas and recovered water, and the heat exchanger 2 is a heat exchanger that cools the exhaust gas with outside air. The recovered water is pressurized by the pump, passes through the heat exchanger 1, and is supplied to the inlet of the combustor. The recovered water is supplied to the electrolyzer via the flow rate regulator (V8) after being pressurized by a pump. The recovered water is supplied to the electrolyzer through a flow rate adjusting valve (V1) after being pressurized by a pump and heated by a heat exchanger. By doing so, the water supplied to the electrolyzer and the turbine can be circulated, and the replenishment of water becomes unnecessary.

  The temperature of water supplied to the electrolyzer is measured by a thermometer (T1), and the temperature of water supplied to the electrolyzer is adjusted to a predetermined temperature (80 to 90 ° C) by adjusting V1 and V8. . When increasing the temperature, adjustment is made to increase the opening of V1. The opposite is true when lowering the temperature. By increasing the water supplied to the electrolyzer to a predetermined temperature, it is possible to increase the conversion efficiency for converting the electric power of the electrolyzer into hydrogen. The remaining amount of the water tank is managed by a level meter (L). V1, V2, and V8 are adjusted according to the amount of water in the water tank. When L is less than or equal to a predetermined value, the supply of V2 is prohibited to prioritize the water supplied to the electrolyzer.

  The operation method of the flow rate regulator at the turbine output lower limit will be described below with reference to Table 1.

(1) The amount of electric power supplied to the electrolyzer is increased when the remaining amount L of the water tank exceeds a predetermined value (Pattern 1).
V1 and V8 are increased, the amount of water supplied to the electrolyzer is increased, and the amounts of hydrogen and oxygen to be electrolyzed are increased. And the supply amount of hydrogen and oxygen to the turbine is increased by increasing V3 and V5. At this time, in order to make the amount of oxygen supplied to the combustor a predetermined amount (the amount of oxygen with respect to the total fuel amount of engine fuel and hydrogen), V7 is reduced and the amount of air supply is reduced. V6 is closed and all the oxygen produced by the electrolyzer is supplied. Furthermore, in order to make the amount of the inert gas supplied to the combustor a predetermined amount (total amount of oxygen, nitrogen, and water vapor with respect to the total fuel amount of engine fuel and hydrogen), V2 is increased and the amount of water vapor is increased. Further, V4 is reduced in order to reduce the amount of natural gas supplied to the combustor. This controls the output from the turbine.

(2) The amount of power supplied to the electrolyzer increases when the water tank remaining amount L is below a predetermined value (Pattern 2).
Since the remaining amount of water is small, V2 is reduced and water supplied to the combustor is reduced. V1 and V8 are increased and water is supplied in preference to the electrolyzer. This gives priority to reducing the engine fuel by using surplus power as fuel without throwing it away. Since the water vapor supplied to the combustor decreases in the pattern 2, V5 and V7 are smaller than those in the pattern 1, and the amount of the inert gas supplied to the combustor is increased by increasing the amount of air supplied to the combustor. Adjust so that V6 is adjusted so that P1 falls within a predetermined range.

(3) The remaining amount L of the water tank is less than a predetermined value and the amount of power supplied to the electrolyzer is more than a predetermined value (Pattern 3)
When the amount of power supplied to the electrolyzer exceeds a predetermined level, the amount of hydrogen supplied to the combustor increases and the conventional fuel becomes smaller. For this reason, the concentration of water vapor during combustion produced from hydrogen is increased. Although the water vapor is recovered using the heat exchangers 1 and 2, a part of the water vapor is discharged without being condensed under a predetermined outside air temperature and heat exchange pressure. Therefore, when the water in the water tank is below a predetermined value, V1, V8, V3, and V4 are adjusted so that the concentration of water vapor generated from engine fuel (natural gas, etc.) is not less than a predetermined value. Thus, the water vapor component generated from hydrogen is controlled to be condensed. FIG. 24 shows the supply ratio of hydrogen generated from the electrolyzer in the fuel supplied to the engine generator (turbine) and the water vapor concentration in the exhaust gas corresponding thereto. The water vapor concentration in the exhaust gas is the water vapor concentration derived from the combustion of natural gas (methane equivalent) and the total water vapor concentration of the combustion of natural gas and hydrogen. If the cooler such as a chiller is not used when the outside air temperature is 40 ° C., the concentration at which water in the exhaust can be condensed is 6.2% or more of water vapor (hatched portion in FIG. 24). When the supply amount of hydrogen is increased, the concentration of water vapor derived from the combustion of natural gas decreases and the amount of water vapor derived from the combustion of hydrogen increases, so under conditions where the hydrogen supply rate is about 40% or more, it is derived from the combustion of hydrogen. It becomes difficult to condense a part of the water vapor. As a result, the amount of recovered water decreases and it becomes difficult to secure the water supplied to the electrolyzer. Therefore, when the remaining amount of the water tank is less than a predetermined value, the hydrogen supply ratio needs to be 40% or less (when the outside air temperature is 40 degrees). The threshold value of the hydrogen supply ratio varies depending on the outside air temperature. For example, when the outside air temperature is 25 ° C., the threshold value of the hydrogen supply ratio is about 70%. This depends on the relationship of the vapor concentration to the outside air temperature as shown in FIG. Therefore, by controlling the threshold value of the hydrogen supply ratio according to the outside air temperature, the supply ratio of surplus power can be increased in a wide range of regions and times, and the system has high environmental resistance. The threshold value of the hydrogen supply ratio is controlled by adjusting V3 and V4 in the configuration diagram. Accordingly, the supply amounts V1 and V8 of water supplied to the electrolyzer are controlled.

S Power supply system
R Renewable energy generator
1 Solar power generator
2 Wind power generator
3 PCS
4 Power converter
5 Power distribution device
6 Electrolyzer
7 Engine generator
8 Fuel tank
9 Power conditioner
10 lines
11 Control unit
101 Hydrogen fuel supply system
102 oxygen supply
103 engine fuel supply system
104 Renewable energy power generation measuring device
105 hydrogen flow meter
106 oxygen flow meter
107 engine generator
108 Power supply meter
109 Electric power measuring device for demand
201 valve
202 valve
203 valve
301 buffer tank
401 heat exchanger
402 water tank
403 water supply equipment
404 water supply equipment
405 heat exchanger
406 water supply device

Claims (11)

A power supply system that supplies power using both power generation by renewable energy and power generation by an engine generator,
A power generator that converts renewable energy into electrical energy;
A power distribution device for supplying a part of the power obtained by the power generation device to the electrolysis device;
An electrolyzer for producing hydrogen and oxygen using the power supplied from the power distribution device;
First supply means for supplying hydrogen and oxygen from the electrolyzer to the engine generator;
A fuel tank for storing engine fuel to be supplied to the engine generator;
Second supply means for supplying engine fuel from the fuel tank to the engine generator;
A control unit that electronically controls the power supply system,
The engine generator generates power using at least one of hydrogen and engine fuel as fuel, and the control unit changes the load variation rate of the engine generator from the power distribution device to the electrolysis device so as to fall within a predetermined range. A power supply system that controls the amount of power to be supplied.   The control unit according to claim 1, wherein when the load change rate of the engine generator is less than a predetermined lower limit value so that the load fluctuation rate of the engine generator falls within a predetermined range, the control unit moves to the electrolyzer by the power distribution device. When the rate of change in the amount of power generated by the engine generator is greater than a predetermined upper limit value, control is performed to reduce the amount of power supplied to the electrolyzer by the power distribution device. system.   The control unit according to claim 2, wherein the control unit increases the amount of power generated by the engine generator by a predetermined range based on the rate of change in the amount of power for grid demand and the rate of change in the amount of power of the power generator. A power supply system that controls the amount of power supplied to a decomposition apparatus.   The power supply system according to claim 1, further comprising a buffer tank that stores hydrogen generated by the electrolyzer.   2. The engine generator according to claim 1, wherein the engine generator includes a first heat exchanger that recovers water in the exhaust gas in an exhaust pipe, and a water tank that can store the water recovered by the heat exchanger; And a water supply device for supplying the water to at least one of the electrolyzer and the engine generator.   6. The engine generator according to claim 5, wherein the engine generator includes a second heat exchanger for heating water supplied from the water tank to an exhaust pipe, and water or steam heated by the second heat exchanger. Is supplied from the water supply means to one or both of the electrolyzer and the engine generator.   6. The water tank according to claim 5, wherein the water tank includes a level meter, and the control unit supplies the engine generator with a predetermined amount or more of hydrogen generated from the electrolyzer when the amount of recovered water in the water tank is a predetermined amount or less. A power supply system that is prohibited from performing. In Claim 1, said 1st supply means is provided with a flow rate detection device which detects flow rates of hydrogen and oxygen which are generated with said electrolysis device,
The control unit controls the supply amount of engine fuel supplied from the second supply means to the engine generator based on the flow rates of hydrogen and oxygen detected by the flow rate detection device. Power supply system.   9. The power supply system according to claim 8, wherein the control unit includes a control unit that controls the engine based on detection values of a flow rate detection device that detects flow rates of hydrogen and oxygen.   9. The control unit according to claim 8, wherein the control unit determines the amount of power to be supplied to the electrolyzer and the amount of power generated by the engine generator based on the amount of power demand and the amount of power generated by the power generation device, and the power distribution device; A power supply system for controlling the engine generator.   9. The power supply amount to the electrolyzer by the power distribution device according to claim 8, wherein, when the power amount of the power generation device with respect to the demand power amount is equal to or greater than a predetermined amount, A power supply system that performs control to increase the power.

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