JP4653767B2 - Power generation system control method - Google Patents

Description

  The present invention relates to a method for controlling a power generation system configured to operate a generator by the output of a gas engine.

  In a power generation system configured to operate a gas engine using two types of fuel, a main fuel gas such as city gas and a secondary fuel gas such as biogas, and operate the generator by the output of the gas engine, The system method is adopted. For example, according to the calorific value of the auxiliary fuel gas, the supply flow rate of the mixture of the main fuel gas and combustion air is adjusted to mix and burn two types of fuel, the main fuel gas and the auxiliary fuel There is a system that uses a fuel mixed with gas and performs combustion while controlling the air ratio of combustion air.

  For example, in Patent Document 1, there is a gas engine configured to supply a gas engine with a mixture of an auxiliary fuel gas such as biogas and combustion air and a main fuel gas such as city gas to perform operation. It is disclosed. In this gas engine, by utilizing the negative pressure generated when combustion air passes through the mixer, the auxiliary fuel gas is sucked into the mixer to generate these air-fuel mixtures. Further, the air ratio is controlled by adjusting the opening of a valve for adjusting the supply flow rate of the main fuel gas based on the output fluctuation of the oxygen sensor or NOx sensor provided in the exhaust system of the gas engine. In the mixer, after the mixture of combustion air and auxiliary fuel gas and the main fuel gas are mixed, the supply flow rate of the two fuel mixture to the gas engine is adjusted by the throttle valve, and the gas is The engine speed or load is controlled.

In many power generation systems using a gas engine and a generator, the generator is connected to a commercial power source (50 Hz or 60 Hz AC power source) to generate power at a constant rotational speed synchronized with the frequency of the commercial power source. ing.
In addition, in the gas engine that performs combustion by mixing the above two kinds of fuels, the operation is started using the main fuel gas such as city gas, and after the output of the gas engine is stabilized, the auxiliary fuel gas such as biogas is used. Has started.

However, in a power generation system using a gas engine that mixes and burns the above two types of fuel, when the generator is operated in a grid-connected manner with a commercial power supply, the supply of secondary fuel gas such as biogas is started. Then, the supply amount of combustion air is insufficient, the air ratio is rapidly decreased (becomes rich in gas), and the power generation output of the generator is rapidly increased. On the other hand, when the generator is operated in a grid-connected manner with the commercial power supply, if the supply of the auxiliary fuel gas such as biogas is cut off, the supply amount of combustion air becomes excessive, and the air ratio increases rapidly ( The power output of the generator will drop sharply.
Therefore, there is a possibility that the output of the gas engine becomes extremely unstable, which may adversely affect the durability of the gas engine.

  It is also conceivable to start and shut off the supply of the auxiliary fuel gas by using a control valve whose opening degree can be controlled by a control device and gradually changing the opening degree of the control valve. However, in this case, a control valve and a control device for controlling the control valve are newly required, which complicates the mechanical and electrical structure of the power generation system.

JP 2005-30302 A

  The present invention has been made in view of such a conventional problem. When the gas engine is operated using the main fuel gas and the auxiliary fuel gas and the generator is connected to the commercial power source, special control is performed. It is an object of the present invention to provide a method for controlling a power generation system that can stably operate a gas engine without performing the above.

A first invention is a gas engine having a plurality of cylinders;
A generator operated by the output of the gas engine;
An air pipe to which combustion air is supplied;
An auxiliary fuel pipe to which an auxiliary fuel gas such as biogas is supplied;
A solenoid valve provided in the auxiliary fuel pipe;
When the solenoid valve is closed, the combustion air flowing from the air pipe is allowed to pass therethrough, and when the solenoid valve is open, the combustion air flowing from the air pipe is transferred to the combustion fuel from the auxiliary fuel pipe. A first mixer that mixes the inflowing auxiliary fuel gas to create a first air-fuel mixture;
A main fuel pipe to which main fuel gas is supplied;
A throttle valve provided in the main fuel pipe;
A second mixer for producing a second air-fuel mixture by mixing the combustion air or the first air-fuel mixture flowing in from the first mixer with the main fuel gas whose flow rate is adjusted by the throttle valve from the main fuel pipe. When,
Using the exhaust gas from the gas engine, compressing the second gas mixture flowing in from the second mixer, and creating a compressed gas mixture;
An intake manifold that supplies the compressed air-fuel mixture flowing from the supercharger in a branched manner to the plurality of cylinders;
A control computer that adjusts the opening of the throttle valve so that the power generation output of the generator becomes a target output;
A control method of a power generation system configured to apply a load to the generator when the power generation output of the generator is connected to a commercial power source,
When starting the power generation system, the electromagnetic valve is closed to start a main fuel single operation using the main fuel gas, and the electromagnetic valve is opened to supply the auxiliary fuel gas to the gas engine. A secondary fuel supply start step for starting supply and starting a two-fuel co-firing operation using the main fuel gas and the secondary fuel gas, and a grid connection for starting grid interconnection with the commercial power source of the generator The system start step is sequentially performed,
When stopping the power generation system, a grid connection disconnecting step for disconnecting the grid connection with the commercial power source of the generator, and closing the solenoid valve to supply the auxiliary fuel gas to the gas engine. A sub-fuel supply shut-off step for shutting off is sequentially performed.

In the control method for the power generation system of the present invention, when the generator is connected to the commercial power source, the supply start timing and the supply cutoff timing of the auxiliary fuel gas are devised.
When starting the power generation system of the present invention, as a starting step, the solenoid valve is closed and the main fuel single operation using the main fuel gas is started. The main fuel single operation can be performed until the rotational speed of the gas engine (and the generator) reaches a substantially constant rotational speed that is synchronized with the frequency (50 Hz or 60 Hz) of the commercial power source.

Next, as a secondary fuel supply start step, the solenoid valve is opened to start the supply of the secondary fuel gas to the gas engine, and the two-fuel mixed combustion operation using the main fuel gas and the secondary fuel gas is started. At this time, since the generator is not grid-connected to the commercial power source, the generator is in a no-load state. Therefore, it is possible to prevent a sudden load from being applied to the generator and a sudden increase in the power generation output of the generator.
Further, when the supply of the auxiliary fuel gas is started, the rotational speed of the gas engine (and the generator) is instantaneously increased and the amount of combustion air sucked into the first mixer is increased, so that the air ratio becomes small ( Gas-rich) is alleviated. At this time, the gas engine is also in a no-load state, and the rotational speed of the gas engine can quickly return to a substantially constant rotational speed.

  Then, the grid connection with the commercial power supply of a generator is started as a grid connection start step. This grid connection can be started after the instantaneously increased rotational speed of the gas engine returns to a substantially constant rotational speed. Thereby, after the two-fuel mixed combustion operation is stabilized, a load can be applied to the generator, and the operation of the gas engine can be prevented from becoming unstable.

Then, the two-fuel co-firing operation is performed in the gas engine, and in the power generation system, the load following operation can be performed so that the power generation output of the power generator becomes a target output for driving the load on the power generator.
Specifically, when performing this load following operation, a first mixture of combustion air and auxiliary fuel gas is produced in the first mixer, and the first mixture and main fuel gas are produced in the second mixer. A second gas mixture is created. Next, in the supercharger, the second air-fuel mixture is compressed to produce a compressed air-fuel mixture, and this compressed air-fuel mixture is supplied to a plurality of cylinders in the gas engine via the intake manifold. The generator can be operated at the target output by adjusting the opening of the throttle valve by the control computer and adjusting the supply flow rate of the main fuel gas to the gas engine.

  On the other hand, when the power generation system of the present invention is stopped, the grid connection with the commercial power source of the generator is cut off as the grid connection cutoff step. Next, as a secondary fuel supply cutoff step, the solenoid valve is closed to shut off the supply of secondary fuel gas to the gas engine. The supply of the auxiliary fuel gas can be interrupted after the load on the generator becomes almost unloaded. Therefore, it is possible to prevent the load on the generator from suddenly disappearing and the power generation output of the generator from rapidly decreasing.

Further, when the supply of the auxiliary fuel gas is cut off, the rotational speed of the gas engine (and the generator) is instantaneously reduced, and the amount of combustion air sucked into the first mixer is reduced, so that the air ratio is increased ( To become a gas lean). Therefore, it is possible to prevent the operation of the gas engine from becoming unstable.
Further, in the present invention, it is not necessary to use a valve for controlling the opening other than the throttle valve, the mechanical and electrical structure of the power generation system is simple, and the control is easy.

  Therefore, according to the control method of the power generation system of the present invention, special control is performed when the gas engine is operated using the main fuel gas and the auxiliary fuel gas and the generator is connected to the commercial power source. Without this, the gas engine can be operated stably.

A second invention is a gas engine having a plurality of cylinders;
A generator operated by the output of the gas engine;
An air pipe to which combustion air is supplied;
A main fuel pipe to which main fuel gas is supplied;
A throttle valve provided in the main fuel pipe;
A first mixer for mixing the combustion air flowing in from the air pipe with the main fuel gas after flow adjustment by the throttle valve from the main fuel pipe to create a first air-fuel mixture;
An auxiliary fuel pipe to which an auxiliary fuel gas such as biogas is supplied;
A solenoid valve provided in the auxiliary fuel pipe;
When the electromagnetic valve is closed, the first air-fuel mixture flowing from the first mixer is allowed to pass through, while when the electromagnetic valve is open, the first air-fuel mixture flowing from the first mixer is passed through the first air-fuel mixture. A second mixer that mixes the sub fuel gas flowing in from the sub fuel pipe to create a second gas mixture;
Using the exhaust gas from the gas engine, compressing the second gas mixture flowing in from the second mixer, and creating a compressed gas mixture;
An intake manifold that supplies the compressed air-fuel mixture flowing from the supercharger in a branched manner to the plurality of cylinders;
A control computer that adjusts the opening of the throttle valve so that the power generation output of the generator becomes a target output;
A control method of a power generation system configured to apply a load to the generator when the power generation output of the generator is connected to a commercial power source,
When starting the power generation system, the electromagnetic valve is closed to start a main fuel single operation using the main fuel gas, and the electromagnetic valve is opened to supply the auxiliary fuel gas to the gas engine. A secondary fuel supply start step for starting supply and starting a two-fuel co-firing operation using the main fuel gas and the secondary fuel gas, and a grid connection for starting grid interconnection with the commercial power source of the generator The system start step is sequentially performed,
When stopping the power generation system, a grid connection disconnecting step for disconnecting the grid connection with the commercial power source of the generator, and closing the solenoid valve to supply the auxiliary fuel gas to the gas engine. According to a third aspect of the present invention, there is provided a method for controlling a power generation system, comprising sequentially performing a step of shutting off a secondary fuel supply.

Also in the power generation system control method of the present invention, when the generator is connected to the commercial power source, the supply start timing and the supply cutoff timing of the auxiliary fuel gas are devised.
And this invention is the same as that of 1st invention except the structure regarding the mixing order of main fuel gas and sub fuel gas differing from the said 1st invention.
Therefore, even with the power generation system control method of the present invention, special control is performed when the gas engine is operated using the main fuel gas and the auxiliary fuel gas and the generator is connected to the commercial power source. The gas engine can be operated stably.

A preferred embodiment in the first and second inventions described above will be described.
In the first and second inventions, city gas (such as 13A) containing methane or the like can be used as the main fuel gas. The secondary fuel gas includes biogas produced by fermenting organic waste (livestock manure, raw garbage, organic residue, sewage sludge, etc.), wood waste (factory waste, building waste, etc.) A fuel gas such as a biogas generated by pyrolyzing and by-product gas generated in a factory or the like can be used. In addition, a general gas fuel different from the main fuel gas may be used as the auxiliary fuel gas.

  In the first invention, the auxiliary fuel pipe is provided with a pressure regulator. In the first mixer, the combustion air flowing from the air pipe passes through the venturi when the electromagnetic valve is open. In response to the suction force generated at the time, the auxiliary fuel gas after the pressure is set by the pressure regulator flows from the auxiliary fuel pipe, so that the auxiliary fuel gas is mixed with the combustion air, and the first mixing is performed. It is preferable to create a mind (claim 2). In the second invention, the sub fuel pipe is provided with a pressure regulator. In the second mixer, when the electromagnetic valve is open, the first air-fuel mixture flowing from the first mixer is According to the suction force generated when passing through the venturi, the secondary fuel gas after the pressure is set by the pressure regulator flows from the secondary fuel pipe to mix the secondary fuel gas into the first mixture. Preferably, the second air-fuel mixture is created (claim 4).

  In these cases, by setting the pressure in the pressure regulator assuming that the amount of heat of the auxiliary fuel gas is maximized, the auxiliary fuel gas with respect to the total supply heat amount of the main fuel gas and the auxiliary fuel gas to the gas engine is set. It is possible to prevent the ratio of the supplied heat quantity from exceeding a predetermined ratio at which stable operation can be performed in the gas engine.

Hereinafter, embodiments of the method for controlling a power generation system according to the present invention will be described with reference to the drawings.
Example 1
As shown in FIG. 1, the power generation system 1 of this example is configured to operate the generator 11 by the output of the gas engine 2 having a plurality of cylinders 21. The power generation system 1 includes a main fuel supply system that supplies a main fuel gas F1 such as city gas to the gas engine 2, and an auxiliary fuel supply system that supplies a sub fuel gas F2 such as biogas to the gas engine 2. The main fuel gas F1 and the auxiliary fuel gas F2 are co-fired and the gas engine 2 is operated.

  As shown in the figure, the auxiliary fuel supply system of this example includes an air pipe 4 to which combustion air A is supplied, an auxiliary fuel pipe 6 to which an auxiliary fuel gas F2 such as biogas is supplied, and an auxiliary fuel pipe 6. The first air-fuel mixture M1 can be created by mixing the auxiliary fuel gas F2 flowing in from the auxiliary fuel pipe 6 with the pressure regulator 61 and the electromagnetic valve 62 provided in the combustion chamber A and the combustion air A flowing in from the air pipe 4. 1 mixer 7A.

  The first mixer 7A sucks the auxiliary fuel gas F2 after the pressure is set by the pressure regulator 61 from the auxiliary fuel pipe 6 according to the suction force generated when the combustion air A flowing in from the air pipe 4 passes through the venturi 71. It is configured to be. The first mixer 7A allows the combustion air A flowing in from the air pipe 4 to pass when the electromagnetic valve 62 is closed, while the combustion air flowing in from the air pipe 4 when the electromagnetic valve 62 is open. A is mixed with the auxiliary fuel gas F2 flowing in from the auxiliary fuel pipe 6 to create a first air-fuel mixture M1.

As shown in FIG. 1, the main fuel supply system of this example includes a main fuel pipe 5 to which the main fuel gas F1 is supplied, a throttle valve 51 provided in the main fuel pipe 5, and a first mixer 7A that flows in from the first mixer 7A. The air-fuel mixture M1 has a second mixer 7B that mixes the main fuel gas F1 whose flow rate is adjusted by the throttle valve 51 from the main fuel pipe 5 to produce the second air-fuel mixture M2.
Further, on the downstream side of the second mixer 7B, a supercharger 3 that compresses the second air-fuel mixture M2 flowing from the second mixer 7B using the exhaust gas G from the gas engine 2 to produce a compressed air-fuel mixture M3, An intake manifold 22 for connecting the compressed mixture M3 flowing from the supercharger 3 to the plurality of cylinders 21 is connected. The power generation system 1 can be controlled by a control computer 8 such as an electronic control unit, and the opening degree of the throttle valve 51 is controlled by the control computer 8 so that the power generation output of the generator 11 becomes a target output.

Further, the generator 11 is configured to generate power by performing grid connection with the commercial power source 100. When the power generation system 1 links the power generation output of the generator 11 with the commercial power source 100, A load 101 is applied to the generator 11.
As shown in FIG. 3, in the control method of the power generation system 1 of this example, when starting the power generation system 1, a start step (starting the main fuel single operation using the main fuel gas F <b> 1 by closing the solenoid valve 62). In step S101), the electromagnetic valve 62 is opened to start the supply of the auxiliary fuel gas F2 to the gas engine 2, and the auxiliary fuel supply for starting the dual fuel co-firing operation using the main fuel gas F1 and the auxiliary fuel gas F2 is started. A start step (S102) and a grid interconnection start step (S103) for starting grid interconnection with the commercial power source 100 of the generator 11 are sequentially performed. Further, when stopping the power generation system 1, a grid connection disconnecting step (S <b> 107) for disconnecting the grid connection with the commercial power source 100 of the generator 11, and closing the electromagnetic valve 62 to supply the auxiliary fuel to the gas engine 2. The auxiliary fuel supply cutoff step (S108) for cutting off the supply of the gas F2 is sequentially performed.

Below, it demonstrates in full detail with the control method of the electric power generation system 1 of this example with FIGS. 1-3.
In this example, as shown in FIG. 1, when the gas engine 2 performs the dual fuel mixed operation and operates the power generation system 1, the control computer 8 opens the throttle valve 51 according to the target output of the generator 11. The amount of the main fuel gas F1 flowing into the second mixer 7B is determined by adjusting the degree, and the rotation speed of the supercharger 3 changes according to the output of the gas engine 2 to rotate the supercharger 3. The inflow amount of the combustion air A to the first mixer 7A is determined according to the number, and the inflow amount of the auxiliary fuel gas F2 to the first mixer 7A is determined according to the inflow amount of the combustion air A.

  In the power generation system 1, the control computer 8 adjusts the opening of the throttle valve 51 according to the target output of the generator 11, so that the amount of heat necessary for producing a target output that is insufficient only with the auxiliary fuel gas F <b> 2. Is supplemented by the main fuel gas F1, and the ratio of the supply flow rate of the auxiliary fuel gas F2 to the total supply flow rate of the main fuel gas F1 and the auxiliary fuel gas F2 to the gas engine 2 can be kept below the initially set ratio. .

As shown in FIG. 1, the generator 11 of this example is configured to generate power at a constant rotational speed synchronized with the frequency (50 Hz or 60 Hz) of the commercial power source 100 when the grid connection with the commercial power source 100 is performed. ing. The generator 11 is configured to generate power at the same voltage and frequency as the commercial power supply 100.
The control computer 8 of this example is configured to perform feedback control by measuring the power generation output of the generator 11 with a wattmeter 81 and adjusting the opening of the throttle valve 51 so that this power generation output becomes the target output. is there. The control computer 8 can also adjust the opening degree of the throttle valve 51 so that the rotational speed of the gas engine 2 becomes the target rotational speed.

As shown in the figure, the supercharger 3 of this example is an exhaust gas supercharger 3 that operates using the energy of the exhaust gas G exhausted from the gas engine 2. The exhaust gas supercharger 3 is connected to a turbine wheel 31 rotated by exhaust gas G passing through an exhaust manifold 23 in which exhaust ports of a plurality of cylinders 21 of the gas engine 2 are gathered, and the turbine wheel 31 on the same axis. The compressor wheel 32 is configured to rotate in response to the rotation of the turbine wheel 31. Then, the second air-fuel mixture M <b> 2 sent from the second mixer 7 </ b> B to the supercharger 3 is converted into a compressed air-fuel mixture M <b> 3 by the compressor wheel 32 and supplied to the gas engine 2.
The throttle valve 51 of this example receives a command from the control computer 8 and operates the valve body 511 disposed at the passage port through which the main fuel gas F1 passes to operate the actuator 512 to adjust the opening degree of the passage port. It is configured to

As shown in FIG. 2, the first mixer 7 </ b> A of this example is provided with a venturi 71 in the main passage 70, and a plurality of tip opening holes 721 in the sub-passage 72 on the outer periphery of the throat portion (throttle portion) 711 in the venturi 71. Is configured to open. Then, when the combustion air A passes through the venturi 71 in the main passage 70, the throat portion 711 in the venturi 71 becomes negative pressure, and the auxiliary fuel gas F2 enters the main passage 70 from the sub passage 72 by the suction force due to the negative pressure. Can be aspirated.
The second mixer 7B of this example also has the same configuration as the first mixer 7A, and is configured to mix the main fuel gas F1 with the first air-fuel mixture M1 passing through the main passage 70.

Further, as shown in FIG. 1, the first mixer 7 </ b> A, the second mixer 7 </ b> B, and the compressor wheel 32 of the supercharger 3 are connected by the intake pipe 12.
Further, the auxiliary fuel pipe 6 of this example is provided with an electromagnetic valve 62 that can open and close the auxiliary fuel pipe 6 on the downstream side of the pressure regulator 61. The electromagnetic valve 62 can be operated by another control computer or the like. When the gas engine 2 is operated by cofiring with the main fuel gas F1 and the auxiliary fuel gas F2, the auxiliary fuel pipe is always operated. When the gas engine 2 is operated by burning only the main fuel gas F1, the auxiliary fuel pipe 6 is closed.

As shown in the figure, in this example, the air pipe 4 is open to the atmosphere, and the auxiliary fuel pipe 6 is connected to a tank (not shown) in which the auxiliary fuel gas F2 such as biogas is generated or stored. ing. The set pressure of the auxiliary fuel gas F2 by the pressure regulator 61 is set to be almost atmospheric pressure.
An air filter 41 for preventing foreign matter from entering the gas engine 2 is disposed at the inlet of the air pipe 4. When the power generation system 1 is operated for a long period of time, on the downstream side of the air filter 41 in the air pipe 4, the negative pressure is slightly lower than the atmospheric pressure due to clogging generated in the air filter 41.

  As shown in FIG. 1, in the pressure regulator 61 of this example, the pilot section 611 that adjusts the set pressure is downstream of the air filter 41 in the air pipe 4 by the pipe 612, and the first mixer It is connected upstream of 7A. The pressure regulator 61 is configured to correct the set pressure to be low according to the decrease in the pressure of the combustion air A downstream of the air filter 41 in the air pipe 4.

  Specifically, when the air filter 41 is clogged when the power generation system 1 is operated for a long period of time, the pressure of the combustion air A on the downstream side of the air filter 41 is slightly increased due to an increase in pressure loss in the air filter 41. Although the pressure decreases, the set pressure of the pressure regulator 61 is corrected to be slightly lower according to the slight decrease in the pressure. Thereby, it is suppressed that the set pressure of the pressure regulator 61 becomes relatively higher than the pressure of the combustion air A on the downstream side of the air filter 41, and the inflow amount of the auxiliary fuel gas F2 to the first mixer 7A. Can be suppressed from increasing slightly. Therefore, when the power generation system 1 is operated for a long period, it is possible to suppress a slight increase in the supply flow rate of the auxiliary fuel gas F2 to the gas engine 2.

In addition, before the operation of the power generation system 1, the supply pressure of the auxiliary fuel gas F2 to the first mixer 7A is determined by setting the set pressure of the pressure regulator 61 to a predetermined value. In the auxiliary fuel pipe 6, a manual valve can be disposed between the pressure regulator 61 and the electromagnetic valve 62. When the power generation system 1 is initially set, the flow rate of the auxiliary fuel gas F2 can be adjusted by operating the manual valve.
Further, when the pressure of the auxiliary fuel gas F2 is set by the pressure regulator 61, when the auxiliary fuel gas F2 contains a gas that easily causes knocking such as hydrogen or butane, the auxiliary fuel gas F2 is used to avoid knocking. The mixing ratio can be suppressed to a predetermined ratio or less.

  Further, the amount of heat supplied to the gas engine 2 of the auxiliary fuel gas F2 can prevent the above-described knocking with respect to the total amount of supplied heat of the main fuel gas F1 supplied to the gas engine 2 and the amount of supplied heat of the auxiliary fuel gas F2. Can be determined by range. Further, the supply heat amount of the main fuel gas F1 can be determined within a range that can follow a rapid load fluctuation in the generator 11 with respect to the total supply heat amount. The gas engine 2 can be operated even if the supply heat amount of the auxiliary fuel gas F2 is larger than the supply heat amount of the main fuel gas F1. The supply heat amount of the main fuel gas F1 is considered to be at least about 10% with respect to the total supply heat amount.

In the power generation system 1 of this example, when performing the two-fuel co-firing operation, the ratio of the amount of heat supplied to the gas engine 2 of the auxiliary fuel gas F2 is always set to a predetermined ratio at which stable operation can be performed without performing special control. Can be kept below.
Specifically, in the power generation system 1 of this example, the inflow amount of the auxiliary fuel gas F2 to the first mixer 7A is adjusted by the pressure regulator 61 provided in the auxiliary fuel pipe 6, and The ratio of the supply flow rate of the sub fuel gas F2 to the total supply flow rate of the main fuel gas F1 and the sub fuel gas F2 is initially set within a range that does not exceed a predetermined ratio at which the gas engine 2 can be stably operated.

When performing this initial setting, it is assumed that the amount of heat of the auxiliary fuel gas F2 is maximized, and the amount of heat supplied to the auxiliary fuel gas F2 with respect to the total amount of supplied heat of the main fuel gas F1 and the auxiliary fuel gas F2 to the gas engine 2 is set. The ratio of the supply flow rate of the auxiliary fuel gas F2 is set within a range in which the ratio does not exceed a predetermined ratio at which stable operation can be performed in the gas engine 2.
When performing the initial setting, the flow rate can be finely adjusted by adjusting the set pressure by the pressure regulator 61 and adjusting the opening of the manual valve provided in the auxiliary fuel pipe 6.

  In this example, when the two-fuel mixed combustion operation is performed in the gas engine 2 and the power generation system 1 is operated, the first mixture M1 of the combustion air A and the auxiliary fuel gas F2 is generated in the first mixer 7A. Thus, in the second mixer 7B, a second mixture M2 of the first mixture M1 and the main fuel gas F1 is created. Next, in the supercharger 3, the second mixture M <b> 2 is compressed to produce a compressed mixture M <b> 3, and this compressed mixture M <b> 3 is supplied to the plurality of cylinders 21 in the gas engine 2 via the intake manifold 22. . The generator 11 can be operated at the target output by adjusting the opening of the throttle valve 51 by the control computer 8 and adjusting the supply flow rate of the main fuel gas F1 to the gas engine 2.

In the power generation system 1 of this example, when the output of the gas engine 2 is increased, the opening degree of the throttle valve 51 is increased by a command from the control computer 8, and the supply flow rate of the main fuel gas F1 to the gas engine 2 is increased. . At this time, when the temperature of the exhaust gas G from the gas engine 2 increases, the expansion work of the supercharger 3 increases, and the rotational speed of the supercharger 3 increases. Thereby, the inflow amount of the second air-fuel mixture M2 to the supercharger 3, the inflow amount of the first air-fuel mixture M1 to the second mixer 7B, and the inflow amount of the combustion air A to the first mixer 7A are increased. As the suction force in the venturi 71 of the first mixer 7A increases, the inflow amount of the auxiliary fuel gas F2 to the first mixer 7A increases.
Thus, when the supply flow rate of the main fuel gas F1 to the gas engine 2 increases, the supply flow rates of the combustion air A and the auxiliary fuel gas F2 to the gas engine 2 can also be increased.

On the other hand, when the output of the gas engine 2 is reduced, the opening degree of the throttle valve 51 is reduced by a command from the control computer 8, and the supply flow rate of the main fuel gas F <b> 1 to the gas engine 2 is reduced. At this time, when the temperature of the exhaust gas G from the gas engine 2 decreases, the expansion work of the supercharger 3 decreases, and the rotational speed of the supercharger 3 decreases. Thereby, the inflow amount of the second air-fuel mixture M2 to the supercharger 3, the inflow amount of the first air-fuel mixture M1 to the second mixer 7B, and the inflow amount of the combustion air A to the first mixer 7A are reduced. As the suction force in the venturi 71 of the first mixer 7A decreases, the inflow amount of the auxiliary fuel gas F2 to the first mixer 7A decreases.
Thus, when the supply flow rate of the main fuel gas F1 to the gas engine 2 is reduced, the supply flow rates of the combustion air A and the auxiliary fuel gas F2 to the gas engine 2 can also be reduced.

  In the power generation system 1 of this example, when the composition or the like of the auxiliary fuel gas F2 changes and the amount of heat changes, the change in the amount of heat can be compensated by the supply flow rate of the main fuel gas F1. Specifically, when the amount of heat of the auxiliary fuel gas F2 decreases, the control computer 8 increases the opening of the throttle valve 51 so that the power generation output of the generator 11 becomes the target output, The supply flow rate of the main fuel gas F1 can be increased. On the other hand, when the amount of heat of the auxiliary fuel gas F2 increases, the control computer 8 decreases the opening of the throttle valve 51 so that the power generation output of the generator 11 becomes the target output, and the main fuel gas to the gas engine 2 The supply flow rate of F1 can be reduced. Thereby, in this example, the fuel gas of the calorie | heat amount required in order to make up the fluctuation | variation of the calorie | heat amount of the sub fuel gas F2 and the generator 11 output target output can always be supplied to the gas engine 2. FIG.

  Further, the pressure of the auxiliary fuel gas F2 supplied from the auxiliary fuel pipe 6 to the first mixer 7A is set to a predetermined value by the pressure regulator 61, so that the original pressure of the auxiliary fuel gas F2 in the tank or the like fluctuates. Even so, the inflow amount of the auxiliary fuel gas F2 to the first mixer 7A can be stably changed in accordance with the inflow amount of the combustion air A to the first mixer 7A. The inflow amount of the auxiliary fuel gas F2 to the first mixer 7A is always determined by the inflow amount of the combustion air A to the first mixer 7A and the set pressure by the pressure regulator 61, and the main fuel to the gas engine 2 is determined. The supply flow rate of the auxiliary fuel gas F2 to the gas engine 2 can be stably changed according to the change in the supply flow rate of the gas F1.

Thereby, the ratio of the supply flow rate of the auxiliary fuel gas F2 to the gas engine 2 with respect to the total supply flow rate of the main fuel gas F1 and the auxiliary fuel gas F2 to the gas engine 2 is stable in the initially set rate, that is, the gas engine 2. It is possible not to exceed a predetermined ratio at which driving is possible.
Even when the amount of heat of the auxiliary fuel gas F2 changes or when the load 101 on the generator 11 changes and the output of the gas engine 2 changes, the main fuel gas F1 and the auxiliary fuel gas F2 to the gas engine 2 also change. Thus, the ratio of the supply heat amount of the auxiliary fuel gas F2 to the total supply heat amount can be prevented from exceeding a predetermined ratio at which the gas engine 2 can be stably operated. Therefore, it is possible to prevent the operation of the gas engine 2 from becoming unstable when the two-fuel mixed combustion operation is performed.

  Therefore, according to the power generation system 1 of this example, the ratio of the amount of heat supplied to the gas engine 2 without using the valve for controlling the opening other than the throttle valve 51 and without performing special control. Can be kept below a predetermined ratio at which stable operation is always possible.

  Further, in the power generation system 1 of this example, the combustion air A is supplied to the gas engine 2 in accordance with the amount of heat of the fuel gas supplied to the gas engine 2. Therefore, without performing special control, the air ratio in the gas engine 2 (the excess air ratio, that is, the value obtained by dividing the actually supplied air amount by the amount of air required for completely burning the fuel gas theoretically). It can be kept almost constant. Note that the air ratio in the gas engine 2 may slightly change under the influence of the characteristics of the supercharger 3, the temperature of the combustion air A, and the like.

Further, in the power generation system 1 of this example, the following control can be performed at the time of starting and stopping to prevent the operation of the gas engine 2 from becoming unstable. Below, the control method of the electric power generation system 1 and its effect are demonstrated with FIG.
Specifically, when starting the power generation system 1 of this example, as a starting step (step S101 in FIG. 3), the solenoid valve 62 is closed and the main fuel single operation using the main fuel gas F1 is started. At this time, the power generation output of the generator 11 is in a state where the grid connection with the commercial power source 100 is cut off. Further, the main fuel single operation is performed until the rotation speed of the gas engine 2 (and the generator 11) reaches a substantially constant rotation speed synchronized with the frequency (50 Hz or 60 Hz) of the commercial power supply 100. And the frequency and voltage of the generator 11 are raised to a rated value.

Next, as a secondary fuel supply start step (S102 in FIG. 3), the electromagnetic valve 62 is opened to start the supply of the secondary fuel gas F2 to the gas engine 2, and the main fuel gas F1 and the secondary fuel gas F2 are used. 2. Start the fuel co-firing operation. At this time, since the generator 11 is not grid-connected to the commercial power source 100, the generator 11 is in an unloaded state. Therefore, it is possible to prevent a sudden load 101 from being applied to the generator 11 and the power generation output of the generator 11 from rapidly increasing.
Further, when the supply of the auxiliary fuel gas F2 is started, the rotational speed of the gas engine 2 (and the generator 11) increases instantaneously and the amount of combustion air A sucked into the first mixer 7A increases. Reducing the ratio (becomes gas rich) is alleviated. At this time, the gas engine 2 is also in a no-load state, and the rotational speed of the gas engine 2 can quickly return to a substantially constant rotational speed.

  Then, the grid connection with the commercial power source 100 of the generator 11 is started as a grid connection start step (S103 in FIG. 3). This grid connection can be started after the instantaneously increased rotational speed of the gas engine 2 returns to a substantially constant rotational speed. Thereby, after the two-fuel mixed combustion operation is stabilized, the load 101 can be applied to the generator 11, and the operation of the gas engine 2 can be prevented from becoming unstable.

  As described above, the two-fuel co-firing operation is performed in the gas engine 2, and in the power generation system 1, the load is generated so that the power generation output of the power generator 11 becomes a target output for driving the load 101 for the power generator 11. Follow-up operation can be performed (S104 in FIG. 3). Next, when a stop signal is sent from the management computer of the power generation system 1 to the control computer 8 that controls the throttle valve 51 (S105 in FIG. 3), the control computer 8 decreases the opening of the throttle valve 51 to generate power output. (S106 in FIG. 3).

  Then, when stopping the power generation system 1 of this example, the grid connection with the commercial power source 100 of the generator 11 is shut off as a grid connection cutoff step (S107 in FIG. 3). Next, as the auxiliary fuel supply cutoff step (S108 in FIG. 3), the electromagnetic valve 62 is closed to interrupt the supply of the auxiliary fuel gas F2 to the gas engine 2. The supply of the auxiliary fuel gas F2 can be shut off after the load on the generator 11 becomes almost unloaded. Therefore, it can prevent that the load 101 with respect to the generator 11 lose | disappears rapidly, and the electric power generation output of the generator 11 falls rapidly.

Further, when the supply of the auxiliary fuel gas F2 is cut off, the rotational speed of the gas engine 2 (and the generator 11) is instantaneously reduced, and the amount of combustion air A sucked into the first mixer 7A is reduced. The increase in ratio (becomes gas lean) is alleviated. Therefore, it is possible to prevent the operation of the gas engine 2 from becoming unstable.
In this example, it is not necessary to use a valve for controlling the opening other than the throttle valve 51, the mechanical and electrical structure of the power generation system 1 is simple, and the control is easy.

  Therefore, according to the control method of the power generation system 1 of this example, when the gas engine 2 is operated using the main fuel gas F1 and the auxiliary fuel gas F2, and the generator 11 is connected to the commercial power source 100, The gas engine 2 can be stably operated without performing special control.

(Example 2)
In this example, as shown in FIG. 4, the first mixture M1 obtained by mixing the combustion air A and the main fuel gas F1 is mixed with the auxiliary fuel gas F2 to create the second mixture M2. is there.
The power generation system 1 of this example also includes a main fuel supply system that supplies the main fuel gas F1 such as city gas to the gas engine 2 and an auxiliary fuel supply system that supplies the sub fuel gas F2 such as biogas to the gas engine 2. Have.

  As shown in the figure, the main fuel supply system of this example includes an air pipe 4 to which combustion air A is supplied, a main fuel pipe 5 to which main fuel gas F1 is supplied, and a throttle provided in the main fuel pipe 5. A valve 51 and a first mixer 7A that mixes the combustion fuel A flowing in from the air pipe 4 with the main fuel gas F1 whose flow rate is adjusted by the throttle valve 51 from the main fuel pipe 5 to produce the first mixture M1. is doing.

  The auxiliary fuel supply system of this example flows in from the auxiliary fuel pipe 6 to which the auxiliary fuel gas F2 such as biogas is supplied, the pressure regulator 61 and the electromagnetic valve 62 provided in the auxiliary fuel pipe 6, and the first mixer 7A. A second mixer 7B that mixes the first fuel mixture M1 with the auxiliary fuel gas F2 flowing from the auxiliary fuel pipe 6 to produce the second gas mixture M2.

The second mixer 7B has a sub fuel gas F2 after the pressure is set by the pressure regulator 61 from the sub fuel pipe 6 according to the suction force generated when the first air-fuel mixture M1 flowing from the first mixer 7A passes through the venturi 71. Is configured to be sucked. The second mixer 7B allows the first air-fuel mixture M1 flowing from the first mixer 7A to pass when the electromagnetic valve 62 is closed, while flowing from the first mixer 7A when the electromagnetic valve 62 is open. The first fuel mixture M1 is mixed with the auxiliary fuel gas F2 flowing from the auxiliary fuel pipe 6 so as to produce the second gas mixture M2.
Further, in the pressure regulator 61 of this example, a pilot section 611 that adjusts the set pressure is connected to the intake pipe 12 that connects the first mixer 7A and the second mixer 7B by a pipe 612.

  In this example, when the two-fuel mixed combustion operation in the gas engine 2 is performed and the load following operation of the power generation system 1 is performed, the first mixture M1 of the combustion air A and the main fuel gas F1 is performed in the first mixer 7A. In the second mixer 7B, a second mixture M2 of the first mixture M1 and the auxiliary fuel gas F2 is produced. Next, in the supercharger 3, the second mixture M <b> 2 is compressed to produce a compressed mixture M <b> 3, and this compressed mixture M <b> 3 is supplied to the plurality of cylinders 21 in the gas engine 2 via the intake manifold 22. .

  In the power generation system 1 of this example, the control computer 8 controls the opening degree of the throttle valve 51 according to the target output of the generator 11 to determine the amount of inflow of the main fuel gas F1 into the first mixer 7A. At the same time, the rotational speed of the supercharger 3 changes according to the output of the gas engine 2, and the inflow amount of the combustion air A to the first mixer 7A is determined according to the rotational speed of the supercharger 3, Further, the inflow amount of the auxiliary fuel gas F2 to the second mixer 7B is determined according to the inflow amount of the combustion air A. Thus, the generator 11 can be operated at the target output by adjusting the opening of the throttle valve 51 by the control computer 8 and adjusting the supply flow rate of the main fuel gas F1 to the gas engine 2.

Moreover, the generator 11 of this example is also configured to generate power by performing grid connection with the commercial power source 100, and the power generation system 1 links the power generation output of the generator 11 with the commercial power source 100. Sometimes, a load 101 is applied to the generator 11.
Also in the control method of the power generation system 1 of this example, when starting the power generation system 1 as in the first embodiment, the start step, the auxiliary fuel supply start step, and the grid interconnection start step are sequentially performed. When the power generation system 1 is stopped, the grid interconnection cutoff step and the auxiliary fuel supply cutoff step are sequentially performed.

  Therefore, even when the gas engine 2 is operated using the main fuel gas F1 and the auxiliary fuel gas F2 and the generator 11 is connected to the commercial power source 100 by the control method of the power generation system 1 of this example, The gas engine 2 can be stably operated without performing special control. Also in this example, other configurations are the same as those of the first embodiment, and the same effects as those of the first embodiment can be obtained.

(Confirmation test)
In this confirmation test, when the power generation system 1 is started, the supply of the auxiliary fuel gas F2 to the gas engine 2 is started before the grid connection with the commercial power source 100 of the generator 11 is started (test 1) and the case where the supply of the auxiliary fuel gas F2 to the gas engine 2 is shut off after the grid connection with the commercial power source 100 of the generator 11 is shut off when the power generation system 1 is stopped (test 2). About the change of the driving | running state in the gas engine 2 and the generator 11, it confirmed.
For comparison, when the power generation system 1 is started, the supply of the auxiliary fuel gas F2 to the gas engine 2 is started after starting the grid connection with the commercial power supply 100 of the generator 11 (comparison) When the supply of the auxiliary fuel gas F2 to the gas engine 2 is shut off before the grid connection with the commercial power source 100 of the generator 11 is shut off when the test 1) and the power generation system 1 are stopped (comparison test) As for 2), changes in the operating conditions of the gas engine 2 and the generator 11 were also confirmed.

In this confirmation test, when the power generation system 1 is started and stopped, the opening of the throttle valve 51, the power generation output (electric power) of the generator 11, the rotational speed of the gas engine 2 (and the generator 11), and the air ratio The change was measured.
5, 7, 9, and 11, the horizontal axis represents time (seconds), and the vertical axis represents the opening degree (%) of the throttle valve 51, the power of the generator 11, and the rotational speed of the gas engine 2. FIG. 5 is a graph showing these changes when the power generation system 1 is started or stopped. Note that the electric power of the generator 11 and the rotational speed of the gas engine 2 are both expressed as a percentage of the rated value (vs. rated%).

  6, 8, 10, and 12, the horizontal axis represents time (seconds), and the vertical axis represents the air ratio in the gas engine 2, so that the air ratio at the time of starting or stopping the power generation system 1. It is a graph which shows the change of. 5 and FIG. 6 are measured for Test 1, FIG. 7 and FIG. 8 are for Test 2, FIG. 9 and FIG. 10 are for Comparative Test 1, and FIG. 11 and FIG. The results are shown.

  For test 1, in FIG. 5, before starting grid connection with the commercial power supply 100 of the generator 11, the electromagnetic valve 62 is opened and the supply of the auxiliary fuel gas F2 is started in the vicinity of about 30 (seconds). is doing. At this time, the opening degree of the throttle valve 51 decreases, and the supply amount of the main fuel gas F1 to the gas engine 2 decreases. Further, at this time, it can be seen that the rotational speed of the gas engine 2 slightly increases momentarily. As a result, it can be seen that the air ratio in the gas engine 2 suddenly decreases (becomes rich in gas).

In FIG. 6, it can be seen that when the supply of the auxiliary fuel gas F2 is started, the air ratio is momentarily slightly reduced (gas rich). Here, the change in the air ratio appears later than the supply start timing of the auxiliary fuel gas F2 because the exhaust gas G is sucked and the residual oxygen concentration is measured to obtain the air ratio. is there. Actually, it is considered that the change in the air ratio appears at the supply start timing of the auxiliary fuel gas F2.
As described above, when the supply of the auxiliary fuel gas F2 to the gas engine 2 is started (test 1) before starting the grid connection with the commercial power source 100 of the generator 11, the air ratio in the gas engine 2 is started. It can be seen that the operation of the gas engine 2 can be prevented from becoming unstable.

  Regarding test 2, in FIG. 7, after the grid connection with the commercial power source 100 of the generator 11 is shut off, the electromagnetic valve 62 is opened and the auxiliary fuel gas F2 is supplied in the vicinity of about 30 (seconds). It is shut off. At this time, the opening degree of the throttle valve 51 increases and the supply amount of the main fuel gas F1 to the gas engine 2 increases. Further, at this time, it can be seen that the rotational speed of the gas engine 2 is slightly decreased momentarily. And it turns out that this has eased that the air ratio in gas engine 2 becomes large rapidly (it becomes gas lean).

In FIG. 8, it can be seen that when the supply of the auxiliary fuel gas F2 is cut off, the air ratio is momentarily slightly reduced (gas rich). Here, the change in the air ratio appears later than the supply start timing of the auxiliary fuel gas F2 for the same reason as described above.
As described above, when the supply of the auxiliary fuel gas F2 to the gas engine 2 is cut off after the grid connection with the commercial power source 100 of the generator 11 is cut off (test 2), the air ratio of the gas engine 2 is reduced. It can be seen that there is no sudden rise and it is possible to prevent the operation of the gas engine 2 from becoming unstable.

  Regarding comparative test 1, in FIG. 9, after starting grid connection with the commercial power source 100 of the generator 11, the electromagnetic valve 62 is opened and the auxiliary fuel gas F2 is supplied in the vicinity of about 30 seconds. Has started. At this time, the opening degree of the throttle valve 51 decreases, and the supply amount of the main fuel gas F1 to the gas engine 2 decreases. Further, at this time, it can be seen that the power of the generator 11 is rapidly increased although there is almost no change in the rotational speed of the gas engine 2.

Thus, as shown in FIG. 10, it can be seen that when the supply of the auxiliary fuel gas F2 is started, the air ratio in the gas engine 2 is abruptly decreased (gas rich). Here, the change in the air ratio appears later than the supply start timing of the auxiliary fuel gas F2 for the same reason as described above.
In this way, when the supply of the auxiliary fuel gas F2 to the gas engine 2 is started after starting the grid connection with the commercial power source 100 of the generator 11 (comparative test 1), the air ratio in the gas engine 2 is started. It can be seen that the operation of the gas engine 2 becomes unstable. It can also be seen that it takes a long time for the operation of the gas engine 2 to return to a stable state.

  For comparative test 2, in FIG. 11, before the grid connection with the commercial power source 100 of the generator 11 is shut off, the electromagnetic valve 62 is opened in the vicinity of about 30 (seconds) to supply the auxiliary fuel gas F2. Is shut off. At this time, the opening degree of the throttle valve 51 increases and the supply amount of the main fuel gas F1 to the gas engine 2 increases. In addition, at this time, it is understood that the power of the generator 11 is drastically reduced although there is almost no change in the rotational speed of the gas engine 2.

Accordingly, as shown in FIG. 12, it can be seen that when the supply of the auxiliary fuel gas F2 is cut off, the air ratio in the gas engine 2 is rapidly increased (gas lean). Here, the change in the air ratio appears later than the supply start timing of the auxiliary fuel gas F2 for the same reason as described above.
As described above, when the supply of the auxiliary fuel gas F2 to the gas engine 2 is shut off before the grid connection with the commercial power source 100 of the generator 11 (comparative test 2), the air in the gas engine 2 is It can be seen that there is a rapid increase in the ratio and the operation of the gas engine 2 becomes unstable. It can also be seen that it takes a long time for the operation of the gas engine 2 to return to a stable state.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. FIG. 3 is an explanatory diagram schematically showing a structure of a first mixer in the first embodiment. 2 is a flowchart illustrating a method for controlling the power generation system according to the first embodiment. Explanatory drawing which shows the electric power generation system in Example 2. FIG. The graph which shows the opening degree of the throttle valve at the time of starting of a power generation system, the electric power of a generator, and the rotation speed of a gas engine about the test 1 in a confirmation test. The graph which shows the change of the air ratio at the time of starting of a power generation system about the test 1 in a confirmation test. The graph which shows the change of the opening degree of a throttle valve, the electric power of a generator, and the rotational speed of a gas engine at the time of a stop of a power generation system about test 2 in a confirmation test. The graph which shows the change of the air ratio at the time of a stop of a power generation system about the test 2 in a confirmation test. The graph which shows the change of the opening degree of the throttle valve at the time of starting of a power generation system, the electric power of a generator, and the rotational speed of a gas engine about the comparative test 1 in a confirmation test. The graph which shows the change of the air ratio at the time of starting of a power generation system about the comparative test 1 in a confirmation test. The graph which shows the change of the opening degree of a throttle valve, the electric power of a generator, and the rotational speed of a gas engine at the time of a power generation system stop about the comparative test 2 in a confirmation test. The graph which shows the change of the air ratio at the time of a stop of a power generation system about the comparison test 2 in a confirmation test.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 Commercial power supply 101 Load 1 Power generation system 11 Generator 2 Gas engine 21 Cylinder 22 Intake manifold 3 Supercharger 4 Air piping 5 Main fuel piping 51 Throttle valve 6 Sub fuel piping 61 Pressure regulator 62 Solenoid valve 7A 1st mixer 7B 2nd Mixer 71 Venturi 8 Control computer A Combustion air F1 Main fuel gas F2 Sub fuel gas M1 First mixture M2 Second mixture M3 Compressed mixture G Exhaust gas

Claims (4)

A gas engine with multiple cylinders;
A generator operated by the output of the gas engine;
An air pipe to which combustion air is supplied;
An auxiliary fuel pipe to which an auxiliary fuel gas such as biogas is supplied;
A solenoid valve provided in the auxiliary fuel pipe;
When the solenoid valve is closed, the combustion air flowing from the air pipe is allowed to pass therethrough, and when the solenoid valve is open, the combustion air flowing from the air pipe is transferred to the combustion fuel from the auxiliary fuel pipe. A first mixer that mixes the inflowing auxiliary fuel gas to create a first air-fuel mixture;
A main fuel pipe to which main fuel gas is supplied;
A throttle valve provided in the main fuel pipe;
A second mixer for producing a second air-fuel mixture by mixing the combustion air or the first air-fuel mixture flowing in from the first mixer with the main fuel gas whose flow rate is adjusted by the throttle valve from the main fuel pipe. When,
Using the exhaust gas from the gas engine, compressing the second gas mixture flowing in from the second mixer, and creating a compressed gas mixture;
An intake manifold that supplies the compressed air-fuel mixture flowing from the supercharger in a branched manner to the plurality of cylinders;
A control computer that adjusts the opening of the throttle valve so that the power generation output of the generator becomes a target output;
A control method of a power generation system configured to apply a load to the generator when the power generation output of the generator is connected to a commercial power source,
When starting the power generation system, the electromagnetic valve is closed to start a main fuel single operation using the main fuel gas, and the electromagnetic valve is opened to supply the auxiliary fuel gas to the gas engine. A secondary fuel supply start step for starting supply and starting a two-fuel co-firing operation using the main fuel gas and the secondary fuel gas, and a grid connection for starting grid interconnection with the commercial power source of the generator The system start step is sequentially performed,
When stopping the power generation system, a grid connection disconnecting step for disconnecting the grid connection with the commercial power source of the generator, and closing the solenoid valve to supply the auxiliary fuel gas to the gas engine. A control method for a power generation system, wherein a secondary fuel supply cutoff step for shutting off is sequentially performed. In Claim 1, the sub fuel pipe is provided with a pressure regulator,
In the first mixer, when the electromagnetic valve is open, the pressure by the pressure regulator from the sub fuel pipe is determined according to the suction force generated when the combustion air flowing from the air pipe passes through the venturi. A control method for a power generation system, characterized in that the first fuel-air mixture is created by mixing the secondary fuel gas into the combustion air when the secondary fuel gas after setting flows in. A gas engine with multiple cylinders;
A generator operated by the output of the gas engine;
An air pipe to which combustion air is supplied;
A main fuel pipe to which main fuel gas is supplied;
A throttle valve provided in the main fuel pipe;
A first mixer for mixing the combustion air flowing in from the air pipe with the main fuel gas after flow adjustment by the throttle valve from the main fuel pipe to create a first air-fuel mixture;
An auxiliary fuel pipe to which an auxiliary fuel gas such as biogas is supplied;
A solenoid valve provided in the auxiliary fuel pipe;
When the electromagnetic valve is closed, the first air-fuel mixture flowing from the first mixer is allowed to pass through, while when the electromagnetic valve is open, the first air-fuel mixture flowing from the first mixer is passed through the first air-fuel mixture. A second mixer that mixes the sub fuel gas flowing in from the sub fuel pipe to create a second gas mixture;
Using the exhaust gas from the gas engine, compressing the second gas mixture flowing in from the second mixer, and creating a compressed gas mixture;
An intake manifold that supplies the compressed air-fuel mixture flowing from the supercharger in a branched manner to the plurality of cylinders;
A control computer that adjusts the opening of the throttle valve so that the power generation output of the generator becomes a target output;
A control method of a power generation system configured to apply a load to the generator when the power generation output of the generator is connected to a commercial power source,
When starting the power generation system, the electromagnetic valve is closed to start a main fuel single operation using the main fuel gas, and the electromagnetic valve is opened to supply the auxiliary fuel gas to the gas engine. A secondary fuel supply start step for starting supply and starting a two-fuel co-firing operation using the main fuel gas and the secondary fuel gas, and a grid connection for starting grid interconnection with the commercial power source of the generator The system start step is sequentially performed,
When stopping the power generation system, a grid connection disconnecting step for disconnecting the grid connection with the commercial power source of the generator, and closing the solenoid valve to supply the auxiliary fuel gas to the gas engine. A control method for a power generation system, wherein a secondary fuel supply cutoff step for shutting off is sequentially performed. In Claim 3, the sub fuel pipe is provided with a pressure regulator,
In the second mixer, when the solenoid valve is open, the pressure regulator is supplied from the sub fuel pipe according to the suction force generated when the first air-fuel mixture flowing from the first mixer passes through the venturi. A control method for a power generation system, characterized in that the second fuel gas is created by mixing the second fuel gas into the first air-fuel mixture by the inflow of the sub fuel gas after the pressure is set.

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