JP4747132B2 - Power generation system - Google Patents

Description

  The present invention relates to 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, Patent Document 1 discloses a gas engine configured to operate by supplying an air-fuel mixture of an auxiliary fuel gas such as biogas and combustion air and a main fuel gas such as city gas to the gas engine. Has been. 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.

  However, when the gas engine is operated by co-firing the above two types of fuel, when the supply of the auxiliary fuel gas such as biogas is started, the air ratio is temporarily reduced (gas rich) and the generator The power generation output temporarily increases. On the other hand, when the supply of the auxiliary fuel gas such as biogas is cut off, the air ratio temporarily increases (becomes gas lean) and the power generation output of the generator temporarily decreases. For this reason, the output of the gas engine may become unstable.

  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.

  In the combustion system of Patent Document 2, a governor is provided in the fuel gas supply path in order to prevent excessive fuel from flowing at the start of ignition in the burner, and the first diaphragm chamber and the second diaphragm chamber in this governor. And appropriately controlling the air pressure. However, Patent Literature 2 is a technology related to a burner combustion system, and does not disclose any technology for stabilizing the output of a gas engine that performs a dual fuel mixed combustion operation.

JP 2005-30302 A JP-A-9-178166

  The present invention has been made in view of such conventional problems, and operates a gas engine using main fuel gas and auxiliary fuel gas, and stably operates the gas engine without performing complicated control. It is intended to provide a power generation system that can.

A first invention is a gas engine having a plurality of cylinders;
A generator operated by the output of the gas engine;
An auxiliary fuel pipe to which an auxiliary fuel gas such as biogas is supplied;
A pressure regulator provided in the auxiliary fuel pipe;
An air pipe to which combustion air is supplied;
While the combustion air flowing from the air pipe can be passed, the pressure regulator is supplied from the sub fuel pipe according to the suction force generated when the combustion air flowing from the air pipe passes through the venturi. A first mixer capable of producing the first air-fuel mixture by mixing the sub fuel gas into the combustion air by the inflow of the sub fuel gas after the pressure is set by
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 controller that adjusts the opening of the throttle valve so that the power generation output of the generator becomes a target output;
The loading section for adjusting the outlet pressure of the pressure regulator is connected to the inlet section of the first mixer via a first loading pipe and connected to the outlet section of the first mixer via a second loading pipe. And
The first loading pipe is provided with a first solenoid valve, the second loading pipe is provided with a second solenoid valve, and the first solenoid valve and the second solenoid valve are operated by an operation management controller. Can be controlled to open and close,
When starting the operation of the gas engine, the operation management controller closes the first electromagnetic valve and opens the second electromagnetic valve so that the operation is performed using the main fuel gas. Yes,
When the supply of the auxiliary fuel gas to the gas engine is started, the operation management controller closes the second electromagnetic valve and opens the first electromagnetic valve, thereby opening the first mixer from the inlet of the first mixer. The combustion air is caused to flow into the first loading pipe to gradually increase the pressure at the loading portion of the pressure regulator, and the outlet pressure of the auxiliary fuel gas by the pressure regulator is changed to the combustion air at the inlet portion of the first mixer. It is configured to approach the pressure of
When stopping the supply of the auxiliary fuel gas to the gas engine, the first electromagnetic valve is closed and the second electromagnetic valve is opened by the operation management controller, whereby the first loading pipe is used to open the first electromagnetic valve. The combustion air is caused to flow out to the outlet of the mixer to gradually reduce the pressure in the loading part of the pressure regulator, and the outlet pressure of the auxiliary fuel gas by the pressure regulator is first mixed at the outlet of the first mixer. The power generation system is configured to be close to the pressure of the gas (claim 1).

In the power generation system of the present invention, the device is devised at the start and stop of the supply of the auxiliary fuel gas to the gas engine that performs the dual fuel mixed operation.
Specifically, a first loading pipe connected to the inlet part of the first mixer and a second loading pipe connected to the outlet part of the first mixer are connected to the loading part of the pressure regulator provided in the auxiliary fuel pipe. ing. The first loading pipe and the second loading pipe are each provided with an electromagnetic valve that can be opened and closed by an operation management controller.

  When the operation of the power generation system of the present invention is performed, the operation of the gas engine is started using the main fuel gas in a state where the first electromagnetic valve is closed and the second electromagnetic valve is opened by the operation management controller. By adjusting the throttle valve opening by the controller, the gas engine can be operated using almost only the main fuel gas until the output of the gas engine is stabilized.

  Next, the operation management controller closes the second electromagnetic valve and opens the first electromagnetic valve, and starts supplying the auxiliary fuel gas to the gas engine. When the second solenoid valve is closed, the pressure at the loading portion of the pressure regulator is substantially the same as the pressure of the combustion air at the outlet of the first mixer. When the first solenoid valve is opened, a part of the combustion air passing through the air pipe gradually flows into the pressure regulator loading section via the first loading pipe.

  As a result, the pressure (loading pressure) at the loading portion of the pressure regulator gradually increases, and the outlet pressure of the auxiliary fuel gas by the pressure regulator (the pressure of the auxiliary fuel gas at the outlet portion of the pressure regulator) becomes the inlet portion of the first mixer. Gradually increase to the pressure of the combustion air at. Therefore, the supply amount of the auxiliary fuel gas to the gas engine can be gradually increased, and when the supply of the auxiliary fuel gas to the gas engine is started, the supply heat amount in the gas engine is prevented from rapidly increasing. be able to. Further, in the gas engine, it is possible to prevent the air ratio from becoming temporarily small (gas rich). Therefore, it is possible to prevent the power generation output of the generator from temporarily rising sharply and to prevent a rapid increase in the NOx concentration.

In addition, it is considered that the NOx concentration increases in the following manner when the introduction of the conventional auxiliary fuel gas is suddenly started without using the power generation system of this method.
That is, if the auxiliary fuel gas is rapidly charged, the amount of heat generated by the auxiliary fuel gas in the gas engine increases. At this time, although the control for reducing the supply amount of the main fuel gas by the throttle valve works, since this control is delayed, the total amount of the fuel supply amount (the total supply amount of the main fuel gas and the auxiliary fuel gas) is temporarily On the other hand, the supply amount of combustion air becomes insufficient, resulting in gas richness. Therefore, it is considered that the NOx concentration increases in the gas engine when the conventional injection of the auxiliary fuel gas is suddenly started.

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 controller and adjusting the supply flow rate of the main fuel gas to the gas engine.

  Thereafter, the operation management controller closes the first solenoid valve and opens the second solenoid valve, thereby starting to stop the supply of the auxiliary fuel gas to the gas engine. When the first solenoid valve is closed, the pressure (loading pressure) at the loading portion of the pressure regulator is substantially the same as the pressure of the combustion air at the inlet portion of the first mixer. When the second electromagnetic valve is opened, a part of the combustion air existing in the loading part of the pressure regulator gradually flows out to the outlet part of the first mixer via the second loading pipe.

  As a result, the pressure at the loading portion of the pressure regulator gradually decreases, and the outlet pressure of the auxiliary fuel gas by the pressure regulator gradually decreases so as to become the pressure of the first air-fuel mixture at the outlet portion of the first mixer. Therefore, the supply amount of the auxiliary fuel gas to the gas engine can be gradually decreased, and when the supply of the auxiliary fuel gas to the gas engine is stopped, the supply heat amount in the gas engine is prevented from rapidly decreasing. be able to. Further, in the gas engine, it is possible to prevent the air ratio from temporarily increasing (becoming gas lean). Therefore, it is possible to prevent the power generation output of the generator from being temporarily reduced sharply.

  In the present invention, the operation management controller controls the opening and closing of the first solenoid valve and the second solenoid valve, and does not use a valve for controlling the opening other than the throttle valve. Therefore, the mechanical and electrical structure of the power generation system is simple and easy to control.

  Therefore, according to the power generation system of the present invention, the gas engine can be operated using the main fuel gas and the auxiliary fuel gas, and the gas engine can be stably operated without performing complicated control.

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 pressure regulator provided in the auxiliary fuel pipe;
While the first air-fuel mixture flowing from the first mixer can be passed, the auxiliary fuel pipe is responsive to the suction force generated when the first air-fuel mixture flowing from the first mixer passes through the venturi. A second mixer capable of creating a second air-fuel mixture by mixing the sub-fuel gas into the first air-fuel mixture when the sub-fuel gas after pressure setting by the pressure regulator flows from
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 controller that adjusts the opening of the throttle valve so that the power generation output of the generator becomes a target output;
The loading section for adjusting the outlet pressure of the pressure regulator is connected to the inlet section of the second mixer via the first loading pipe, and is connected to the outlet section of the second mixer via the second loading pipe. And
The first loading pipe is provided with a first solenoid valve, the second loading pipe is provided with a second solenoid valve, and the first solenoid valve and the second solenoid valve are operated by an operation management controller. Can be controlled to open and close,
When starting the operation of the gas engine, the operation management controller closes the first electromagnetic valve and opens the second electromagnetic valve so that the operation is performed using the main fuel gas. Yes,
When the supply of the auxiliary fuel gas to the gas engine is started, the operation management controller closes the second electromagnetic valve and opens the first electromagnetic valve, thereby opening the first mixer from the inlet of the second mixer. The first air-fuel mixture is caused to flow into the first loading pipe to gradually increase the pressure at the loading portion of the pressure regulator, and the outlet pressure of the secondary fuel gas by the pressure regulator is changed to the first at the inlet portion of the second mixer. It is configured to approach the pressure of the mixture,
When stopping the supply of the auxiliary fuel gas to the gas engine, the operation management controller closes the first electromagnetic valve and opens the second electromagnetic valve, thereby opening the second loading pipe from the second loading pipe. The first air-fuel mixture is caused to flow out to the outlet of the mixer to gradually reduce the pressure in the loading portion of the pressure regulator, and the outlet pressure of the auxiliary fuel gas by the pressure regulator is changed to the second at the outlet of the second mixer. The power generation system is configured to approach the pressure of the air-fuel mixture (Claim 3).

Also in the power generation system of the present invention, the device is devised at the start and stop of the supply of the auxiliary fuel gas to the gas engine that performs the dual fuel mixed operation.
And the structure of this invention is the same as that of the 1st invention except the structure regarding the mixing order of main fuel gas and sub fuel gas differing from the structure of the said 1st invention.
Therefore, even with the power generation system of the present invention, the same effects as those of the first invention can be obtained, and the gas engine is operated using the main fuel gas and the auxiliary fuel gas without performing complicated control. The gas engine can be operated stably.

A preferred embodiment in the first and second inventions described above will be described.
In the first aspect of the present invention, the auxiliary fuel piping is provided with an auxiliary fuel solenoid valve that can be controlled to be opened and closed by the operation management controller, and when the operation of the gas engine is started, the operation management controller The secondary solenoid valve and the first solenoid valve are closed and the second solenoid valve is opened. When the supply of the secondary fuel gas to the gas engine is started, the operation management controller When the auxiliary fuel solenoid valve is opened, the second solenoid valve is closed and the first solenoid valve is opened, and when the supply of the auxiliary fuel gas to the gas engine is stopped, the operation management controller To close the first solenoid valve and open the second solenoid valve so that the pressure in the loading part of the pressure regulator is the outlet of the first mixer. After almost a first mixture pressure of definitive same, it is preferable to construct to close the solenoid valve for the auxiliary fuel by the operation management controller (claim 2).

  In the second aspect of the invention, the auxiliary fuel piping is provided with an auxiliary fuel solenoid valve that can be controlled to be opened and closed by the operation management controller, and when the operation of the gas engine is started, the operation management controller The secondary solenoid valve and the first solenoid valve are closed and the second solenoid valve is opened. When the supply of the secondary fuel gas to the gas engine is started, the operation management controller When the auxiliary fuel solenoid valve is opened, the second solenoid valve is closed and the first solenoid valve is opened, and when the supply of the auxiliary fuel gas to the gas engine is stopped, the operation management controller To close the first solenoid valve and open the second solenoid valve so that the pressure in the loading part of the pressure regulator is the outlet part of the second mixer. After almost a second mixture pressure of definitive same, it is preferable to construct to close the solenoid valve for the auxiliary fuel by the operation management controller (claim 4).

  In these cases, when starting the operation of the gas engine, the auxiliary fuel solenoid valve is closed, the supply of the auxiliary fuel gas to the gas engine is shut off, and only the main fuel gas is used in the gas engine. You can drive. Further, when the supply of the auxiliary fuel gas to the gas engine is stopped, the auxiliary fuel electromagnetic valve can be closed to interrupt the supply of the auxiliary fuel gas to the gas engine.

  The timing for closing the auxiliary fuel solenoid valve by the operation management controller can be controlled by a timer (time). For example, the operation control controller closes the first solenoid valve and opens the second solenoid valve, and the pressure in the loading part of the pressure regulator is the first mixture (second mixture) at the outlet of the first mixer (second mixer). It is possible to measure in advance the time when the pressure becomes substantially the same as this pressure, and use this measured time (or time with some margin) as the timer setting time. Then, after the first electromagnetic valve is closed by the operation management controller and the second electromagnetic valve is opened, the auxiliary fuel electromagnetic valve can be closed by the operation management controller after the timer set time has elapsed.

In the first and second aspects of the invention, the loading portion of the pressure regulator is connected to a merging pipe where the first loading pipe and the second loading pipe are merged, and the merging pipe is connected to the merging pipe. A throttle channel portion having a channel cross-sectional area smaller than that of the first loading pipe and the second loading pipe is provided, and the throttle channel unit is configured to gradually increase or decrease the pressure in the loading part of the pressure regulator. (Claim 5).
In this case, the pressure in the loading portion of the pressure regulator can be gradually increased or decreased easily by one throttle channel portion at the start and stop of the supply of the auxiliary fuel gas to the gas engine.
In addition, the said throttle flow path part can also be provided in both the said 1st loading piping and the said 2nd loading piping. Also in this case, the same effect as described above can be obtained.

When the supply of the auxiliary fuel gas to the gas engine is started, the operation control controller opens the auxiliary fuel solenoid valve and closes the second electromagnetic valve. By repeating opening and closing, the pressure in the loading portion of the pressure regulator is gradually increased. When the supply of the auxiliary fuel gas to the gas engine is stopped, the operation management controller performs the first operation. After the solenoid valve is closed, the pressure in the loading portion of the pressure regulator can be gradually decreased by repeatedly opening and closing the second solenoid valve.
In this case, the pressure in the loading part of the pressure regulator is reduced at the start and stop of the supply of the auxiliary fuel gas to the gas engine by simple electrical control that repeatedly opens and closes the first solenoid valve or the second solenoid valve. It can be gradually increased or decreased. This electrical control can also be employed in a configuration in which the throttle channel portion is provided.

The generator is configured so that a load is applied when the power generation output is grid-connected to the commercial power source, and when the power generation output of the generator is grid-connected to the commercial power source. The supply of the auxiliary fuel gas to the gas engine can be started and stopped (claim 7).
In this case, the power generation system can be used in a grid connection with a commercial power source, and even when starting and stopping the supply of the auxiliary fuel gas to the gas engine when performing the grid connection, A temporary increase or decrease in the power generation output of the generator can be prevented.

Hereinafter, embodiments of the power generation system of 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 gas engine 2 is operated by co-firing the main fuel gas F1 and the auxiliary fuel gas F2.

  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 auxiliary fuel gas F2 flowing in from the auxiliary fuel pipe 6 is mixed with the pressure regulator (differential pressure governor) 61 and the auxiliary fuel solenoid valve 62 provided in the combustion chamber A and the combustion air A flowing in from the air pipe 4 to perform the first mixing. And a first mixer 7A capable of producing a gas M1.

  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. Further, the first mixer 7A allows the combustion air A flowing in from the air pipe 4 to pass when the sub fuel electromagnetic valve 62 is closed, while the air pipe 4 when the sub fuel electromagnetic valve 62 is open. Combustion air A flowing in from the auxiliary fuel pipe 6 is mixed with the combustion air A 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 uses the exhaust gas G from the gas engine 2 to compress the second air-fuel mixture M2 flowing from the second mixer 7B 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 controller (computer) 81 such as an electronic control unit, and the opening degree of the throttle valve 51 is controlled by the control controller 81 so that the power generation output of the generator 11 becomes a target output. Is done.

The loading unit 611 for adjusting the outlet pressure of the pressure regulator 61 is connected to the inlet part a of the first mixer 7A via the first loading pipe 64A, and is connected to the first mixer via the second loading pipe 64B. It is connected to the outlet b of 7A.
The first loading piping 64A is provided with a first electromagnetic valve 63A, and the second loading piping 64B is provided with a second electromagnetic valve 63B. The auxiliary fuel solenoid valve 62, the first solenoid valve 63A, and the second solenoid valve 63B can be opened and closed by the operation management controller 82.

As shown in FIG. 3, when starting operation of the gas engine 2, the power generation system 1 closes the auxiliary fuel electromagnetic valve 62 and the first electromagnetic valve 63 </ b> A and opens the second electromagnetic valve 63 </ b> B by the operation management controller 82. In this state, the gas engine 2 is operated using only the main fuel gas F1.
Further, when the power generation system 1 starts to supply the auxiliary fuel gas F2 to the gas engine 2, the operation management controller 82 opens the auxiliary fuel electromagnetic valve 62, closes the second electromagnetic valve 63B, and the first By opening the electromagnetic valve 63A, the combustion air A flows into the first loading pipe 64A from the inlet a of the first mixer 7A, and the pressure in the loading unit 611 of the pressure regulator 61 is gradually increased. The outlet pressure (supply pressure of the auxiliary fuel gas F2) is configured to approach the pressure of the combustion air A at the inlet portion a of the first mixer 7A.

  Further, when stopping the supply of the auxiliary fuel gas F2 to the gas engine 2, the power generation system 1 closes the first electromagnetic valve 63A and opens the second electromagnetic valve 63B by the operation management controller 82, so that the second Combustion air A flows out from the loading pipe 64B to the outlet b of the first mixer 7A to gradually reduce the pressure in the loading part 611 of the pressure regulator 61, and the outlet pressure of the pressure regulator 61 (supply pressure of the auxiliary fuel gas F2) ) To be close to the pressure of the first air-fuel mixture M1 at the outlet b of the first mixer 7A.

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 two-fuel co-firing operation is performed in the gas engine 2 and the power generation system 1 is operated, the controller 81 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 rotational speed of the supercharger 3 changes according to the output of the gas engine 2, and the supercharger 3 rotates. The inflow amount of the combustion air A to the first mixer 7A is determined according to the speed, 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 controller 81 adjusts the opening degree 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 sub fuel gas F2 to the total supply flow rate of the main fuel gas F1 and the sub fuel gas F2 to the gas engine 2 is less than the ratio initially set by the pressure regulator 61. Can keep.

As shown in FIG. 1, the generator 11 of the present example is configured to generate power by performing grid connection with the commercial power supply 100, and the power generation system 1 generates the power generation output of the generator 11 with the commercial power supply 100 and the grid. It is configured such that a load 101 is applied to the generator 11 when connected. Further, the generator 11 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 performing grid connection with the commercial power source 100. The generator 11 is configured to generate power at the same voltage and frequency as the commercial power supply 100.
The controller 81 in this example is configured to perform feedback control by measuring the power generation output of the generator 11 with a wattmeter 811 and adjusting the opening of the throttle valve 51 so that the power generation output becomes a target output. is there. The controller 81 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 coupled 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 concentrated, 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 controller 81 and adjusts the opening degree of the passage port by operating the valve body 511 disposed in the passage port through which the main fuel gas F1 passes through the actuator 512. 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 auxiliary fuel solenoid valve 62 that can open and close the auxiliary fuel pipe 6 on the downstream side of the pressure regulator 61. The auxiliary fuel solenoid valve 62 always opens the auxiliary fuel pipe 6 by the operation management controller 82 when the gas engine 2 is operated by co-firing with the main fuel gas F1 and the auxiliary fuel gas F2. In the gas engine 2, when the operation is performed by burning only the main fuel gas F 1, the sub fuel pipe 6 is closed by the operation management controller 82.

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.
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.

  Further, the inlet part a and the outlet part b of the first mixer 7A and the connection part c of the auxiliary fuel pipe 6 to the first mixer 7A are all at negative pressure. In addition, the pressure of the connecting portion c of the auxiliary fuel pipe 6 to the first mixer 7A is lower than the inlet portion a of the first mixer 7A, and the first pressure is higher than the connecting portion c of the auxiliary fuel pipe 6 to the first mixer 7A. The pressure at the outlet b of the mixer 7A is low.

  Further, the pressure regulator 61 of the present example includes an adjustment valve that adjusts the flow rate of the auxiliary fuel gas F2 according to the opening degree, a diaphragm that senses the outlet pressure of the pressure regulator 61, and transmits the fluctuation of the outlet pressure to the adjustment valve, A differential pressure adjusting spring that sets the outlet pressure is used. The diaphragm and the differential pressure adjusting spring are disposed in the container and constitute a loading portion 611.

As shown in FIG. 1, the pressure regulator 61 of this example is configured to set its outlet pressure by the total pressure of the pressure in the loading portion 611 (loading pressure) and the pressure applied by the differential pressure adjusting spring. When the pressure applied to the loading unit 611 increases, the outlet pressure also increases. When the pressure applied to the loading unit 611 decreases, the outlet pressure also decreases, and the pressure (loading pressure) and pressure in the loading unit 611 are reduced. The outlet pressure of the regulator 61 is balanced.
Thus, by using the pressure regulator 61, the pressure of the combustion air A mixed in the first mixer 7A and the pressure of the auxiliary fuel gas F2 can be kept substantially the same when performing the two-fuel mixed combustion operation. And the change in the mixing ratio can be reduced.

A joining pipe 65 in which the first loading pipe 64A and the second loading pipe 64B are joined is connected to the loading portion 611 of the pressure regulator 61 of this example. The junction pipe 65 is provided with a throttle channel section 66 having a channel cross-sectional area smaller than that of the first loading pipe 64A and the second loading pipe 64B. As the throttle channel section 66, a throttle valve section or the like that can manually adjust the opening degree of the channel such as a needle valve can be used.
Then, the pressure in the loading portion 611 of the pressure regulator 61 can be gradually increased or decreased by the throttle channel portion 66. Further, by appropriately setting and changing the flow path cross-sectional area of the throttle flow path section 66, the inflow speed of the combustion air A flowing into the loading section 611 or the outflow speed of the combustion air A flowing out of the loading section 611 is appropriately set. Can be set.

  The operation management controller 82 is provided with the first electromagnetic valve 63A (at the start of the supply of the auxiliary fuel gas F2) or the second electromagnetic valve 63B (the auxiliary electromagnetic valve 63B). Even when the opening and closing of the fuel gas F2 is stopped repeatedly, the pressure in the loading portion 611 of the pressure regulator 61 is gradually increased (at the start of the supply of the auxiliary fuel gas F2) or decreased (when the auxiliary fuel gas F2 is supplied). (When the supply is stopped). As the time elapses, the time during which the first electromagnetic valve 63A or the second electromagnetic valve 63B is open is lengthened, so that the inflow speed of the combustion air A flowing into the loading unit 611 or the loading unit 611 flows out. The outflow speed of the combustion air A can be set appropriately.

Further, as shown in FIG. 1, the first loading pipe 64A branching from the merging pipe 65 is connected downstream of the air filter 41 in the air pipe 4 and upstream of the first mixer 7A. It is.
The second loading pipe 64B branched from the merging pipe 65 is connected to the intake pipe 12 between the first mixer 7A and the second mixer 7B.

  In the auxiliary fuel pipe 6, a manual valve can be disposed between the pressure regulator 61 and the auxiliary fuel 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. In addition, the flow rate of the auxiliary fuel gas F2 can be adjusted by adjusting the pressure applied by the differential pressure adjusting spring of the pressure regulator 61. In addition, when the auxiliary fuel gas F2 contains a gas that easily causes knocking such as hydrogen or butane, the auxiliary fuel gas is used to avoid knocking by the initial setting of the pressure of the auxiliary fuel gas F2 by the pressure regulator 61. The mixing ratio of F2 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.

  Further, the operation management controller 82 receives a power generation output signal from a power meter 811 or the like that measures the power generation output of the generator 11, and the first electromagnetic valve 63A and the second electromagnetic valve 63B so that the power generation output becomes a target output. It is also possible to configure such that the open / close control is alternately repeated. In this case, it is considered that the gas engine 2 can be operated with the supply amount of the auxiliary fuel gas F2 being almost 100%.

Next, the operation and effect when the two-fuel mixed combustion operation is performed in the gas engine 2 of the power generation system 1 of the present example will be described.
In the power generation system 1 of this example, the auxiliary fuel gas to the first mixer 7A is provided by the pressure regulator 61 provided in the auxiliary fuel pipe 6 and the manual valve provided between the pressure regulator 61 and the auxiliary fuel solenoid valve 62. 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 is adjusted in advance so that the gas engine 2 can stably operate. Set the initial value within a range that does not exceed the ratio.

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 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 the pressure regulator 61 is initially set, the pressure applied by the differential pressure adjusting spring is adjusted while the first electromagnetic valve 63A is opened and the second electromagnetic valve 63B is closed. The outlet pressure of the pressure regulator 61 is adjusted so that the required flow rate flows. Further, when the adjustment cannot be performed only with the differential pressure adjusting spring (cannot be fully throttled), the manual valve provided in the auxiliary fuel pipe 6 can be throttled for adjustment.

  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 controller 81 and adjusting the supply flow rate of the main fuel gas F1 to the gas engine 2.

Further, in the power generation system 1 of this example, when the output of the gas engine 2 is increased, the opening of the throttle valve 51 is increased by a command from the controller 81, and the supply flow rate of the main fuel gas F1 to the gas engine 2 is increased. To increase. 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 controller 81, and the supply flow rate of the main fuel gas F1 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 controller 81 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 controller 81 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.

  In addition, the pressure of the auxiliary fuel gas F2 supplied from the auxiliary fuel pipe 6 to the first mixer 7A by the pressure regulator 61 is set to be substantially the same as the pressure of the combustion air A flowing into the first mixer 7A. This stabilizes the inflow of the auxiliary fuel gas F2 into the first mixer 7A according to the inflow of the combustion air A into the first mixer 7A even if the original pressure in the tank of the auxiliary fuel gas F2 fluctuates. Can be changed. 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 changes in the supply flow rate of the main fuel gas F1 to the gas engine 2. Accordingly, the supply flow rate of the auxiliary fuel gas F2 to the gas engine 2 can be changed stably.

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 the present example, the ratio of the amount of heat supplied to the gas engine 2 without using a valve for controlling the opening other than the throttle valve 51 and without performing complicated 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 complicated 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.

In the power generation system 1 of this example, the device is devised at the start and stop of the supply of the auxiliary fuel gas F2 to the gas engine 2 that performs the two-fuel mixed combustion operation. Hereinafter, the control operation of the power generation system 1 at the start of supply and the stop of the supply of the auxiliary fuel gas F2 and the effects thereof will be described with reference to FIG.
When the power generation system 1 of the present example is operated, only the main fuel gas F1 is used with the secondary fuel solenoid valve 62 and the first solenoid valve 63A being closed and the second solenoid valve 63B being opened by the operation management controller 82. The operation of the gas engine 2 is started using (Step S101 in FIG. 3). 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. Then, the frequency and voltage of the generator 11 are raised to the rated values (S102 in FIG. 3). Subsequently, the grid connection with the commercial power supply 100 of the generator 11 is started (S103 of FIG. 3).

  Next, the operation control controller 82 opens the auxiliary fuel electromagnetic valve 62 and closes the second electromagnetic valve 63B, and then opens the first electromagnetic valve 63A to start supplying the auxiliary fuel gas F2 to the gas engine 2 (FIG. 3 S104). When the second electromagnetic valve 63B is closed, the pressure in the loading part 611 of the pressure regulator 61 is substantially the same as the pressure of the combustion air A at the outlet part b of the first mixer 7A. Since the converging pipe 65 where the first loading pipe 64A joins is provided with a throttle channel portion 66, when the first electromagnetic valve 63A is opened, one of the combustion air A passing through the air pipe 4 is provided. Part gradually flows into the loading part 611 of the pressure regulator 61 via the first loading pipe 64A.

  As a result, the pressure in the loading portion 611 of the pressure regulator 61 gradually increases, and the outlet pressure of the auxiliary fuel gas F2 by the pressure regulator 61 gradually increases to become the pressure of the combustion air A at the inlet portion a of the first mixer 7A. To increase. Therefore, the supply amount of the auxiliary fuel gas F2 to the gas engine 2 can be gradually increased, and when the supply of the auxiliary fuel gas F2 to the gas engine 2 is started, the supply heat amount in the gas engine 2 increases rapidly. Can be prevented. Further, in the gas engine 2, it is possible to prevent the air ratio from becoming temporarily small (gas rich). Therefore, it is possible to prevent the power generation output of the generator 11 from temporarily rising sharply, and to prevent a rapid increase in the NOx concentration.

  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 (S105 in FIG. 3). Next, when a stop signal is sent from the operation management controller 82 of the power generation system 1 to the control controller 81 that controls the throttle valve 51 (S106 in FIG. 3), the controller 81 decreases the opening of the throttle valve 51. The power generation output is reduced (S107 in FIG. 3).

  Next, the operation controller 82 closes the first electromagnetic valve 63A and opens the second electromagnetic valve 63B, thereby stopping the supply of the auxiliary fuel gas F2 to the gas engine 2 (S108 in FIG. 3). . When closing the first electromagnetic valve 63A, the pressure in the loading portion 611 of the pressure regulator 61 is substantially the same as the pressure of the combustion air A at the inlet portion a of the first mixer 7A. The converging pipe 65 where the second loading pipe 64B joins is provided with a throttle channel section 66, so that when the second electromagnetic valve 63B is opened, the combustion pipe existing in the loading section 611 of the pressure regulator 61 is opened. A part of the air A gradually flows out to the outlet b of the first mixer 7A via the second loading pipe 64B.

  As a result, the pressure in the loading portion 611 of the pressure regulator 61 gradually decreases, and the outlet pressure of the auxiliary fuel gas F2 by the pressure regulator 61 becomes the pressure of the first air-fuel mixture M1 in the outlet portion b of the first mixer 7A. Decrease gradually. Therefore, the supply amount of the auxiliary fuel gas F2 to the gas engine 2 can be gradually decreased, and when the supply of the auxiliary fuel gas F2 to the gas engine 2 is stopped, the supply heat amount in the gas engine 2 is rapidly reduced. Can be prevented. Further, in the gas engine 2, it is possible to prevent the air ratio from temporarily increasing (becoming gas lean). Therefore, it is possible to prevent the power generation output of the generator 11 from being temporarily reduced sharply.

  Subsequently, after the outlet pressure of the pressure regulator 61 becomes substantially the same as the pressure of the first air-fuel mixture M1 at the outlet b of the first mixer 7A (the first electromagnetic valve 63A is closed by the operation management controller 82 and the second electromagnetic valve When 63B is opened and the timer set time has elapsed, the operation control controller 82 closes the auxiliary fuel electromagnetic valve 62 to shut off the supply of the auxiliary fuel gas F2 to the gas engine 2 (FIG. 3). S109). Then, the grid connection with the commercial power supply 100 of the generator 11 is interrupted (S110 in FIG. 3).

In the operation of the power generation system 1 of this example, when the grid connection with the commercial power source 100 of the generator 11 is performed, the supply of the auxiliary fuel gas F2 to the gas engine 2 is started, and the generator 11 During the grid connection with the commercial power source 100, the supply of the auxiliary fuel gas F2 to the gas engine 2 was stopped. On the other hand, after the supply of the auxiliary fuel gas F2 to the gas engine 2 is started, the grid connection with the commercial power source 100 of the generator 11 can be started, and the auxiliary fuel gas F2 to the gas engine 2 can be started. After the supply is stopped, the grid connection with the commercial power supply 100 of the generator 11 can be cut off.
That is, according to the power generation system 1 of this example, the operation of the gas engine 2 can be stably continued without considering the timing of starting and shutting off the grid connection with the commercial power source 100.

  In this example, the operation management controller 82 performs open / close control (simple ON / OFF control) of the auxiliary fuel solenoid valve 62, the first solenoid valve 63A, and the second solenoid valve 63B. Other than the above, no valve for controlling the opening is used. The first loading pipe 64A and the second loading pipe 64B have small pipe diameters (inner diameters), and small solenoid valves can be used as the first solenoid valve 63A and the second solenoid valve 63B. Further, the operation management controller 82 may perform ON / OFF control of the auxiliary fuel electromagnetic valve 62, the first electromagnetic valve 63A, and the second electromagnetic valve 63B (control for adjusting the opening degree is unnecessary), and the operation management controller 82 An inexpensive sequencer or the like can be used. Therefore, the mechanical and electrical structure of the power generation system 1 is simple and its control is easy.

  Therefore, according to the power generation system 1 of this example, the gas engine 2 is operated using the main fuel gas F1 and the auxiliary fuel gas F2, and the gas engine 2 is stably operated without performing complicated control. be able to.

(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 for producing the first mixture M1 by mixing 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; is doing.

  The auxiliary fuel supply system of this example includes an auxiliary fuel pipe 6 to which an auxiliary fuel gas F2 such as biogas is supplied, a pressure regulator 61 and an auxiliary fuel electromagnetic valve 62 provided in the auxiliary fuel pipe 6, and a first mixer 7A. And a second mixer 7B that mixes the sub fuel gas F2 flowing in from the sub fuel pipe 6 with the first gas mixture M1 flowing in from the sub fuel pipe 6 to create 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 auxiliary fuel electromagnetic valve 62 is closed, while the second fuel electromagnetic valve 62 is open when the auxiliary fuel electromagnetic valve 62 is open. The first mixed gas M1 flowing from the first mixer 7A is mixed with the auxiliary fuel gas F2 flowing from the auxiliary fuel pipe 6 so as to produce the second mixed gas M2.

As shown in FIG. 4, a merging pipe 65 in which the first loading pipe 64A and the second loading pipe 64B merge is connected to the loading portion 611 of the pressure regulator (differential pressure governor) 61 of this example. The pipe 65 is provided with a throttle channel section 66 having a channel cross-sectional area smaller than that of the first loading pipe 64A and the second loading pipe 64B.
In addition, the first loading pipe 64A branched from the merging pipe 65 is connected to the downstream side of the air pipe 4 at the position where the air filter 41 is disposed and to the upstream side of the first mixer 7A. The second loading pipe 64B branched from the merging pipe 65 is connected to the intake pipe 12 between the second mixer 7B and the supercharger 3.

  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. .

  Further, in the power generation system 1 of this example, the controller 81 controls the opening degree of the throttle valve 51 in accordance with the target output of the generator 11 to determine the inflow amount 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 controller 81 and adjusting the supply flow rate of the main fuel gas F1 to the gas engine 2.

  Further, in the power generation system 1 of this example, when the supply of the auxiliary fuel gas F2 to the gas engine 2 is started, the operation management controller 82 closes the second electromagnetic valve 63B and opens the first electromagnetic valve 63A. The first air-fuel mixture M1 is caused to flow from the inlet a of the second mixer 7B into the first loading pipe 64A to gradually increase the pressure in the loading part 611 of the pressure regulator 61, and the outlet pressure of the pressure regulator 61 is increased to the second. It is configured to approach the pressure of the first air-fuel mixture M1 at the inlet a of the mixer 7B.

  Further, in the power generation system 1 of this example, when the supply of the auxiliary fuel gas F2 to the gas engine 2 is stopped, the operation management controller 82 closes the first electromagnetic valve 63A and opens the second electromagnetic valve 63B. The first air-fuel mixture M1 flows out from the second loading pipe 64B to the outlet b of the second mixer 7B to gradually decrease the pressure in the loading part 611 of the pressure regulator 61, and the outlet pressure of the pressure regulator 61 is reduced to the second mixer. 7B is configured to approach the pressure of the second air-fuel mixture M2 at the outlet b of 7B.

  In addition, the configuration of the power generation system 1 of the present example is the same as that of the first embodiment, and the power generation system 1 of the present example can obtain the same operational effects as those of the first embodiment. The gas engine 2 is operated using the auxiliary fuel gas F2, and the gas engine 2 can be stably operated without performing complicated control.

(Confirmation test)
In this confirmation test, in the power generation system 1 shown in the first embodiment, when the supply of the auxiliary fuel gas F2 to the gas engine 2 is started (test 1), the supply of the auxiliary fuel gas F2 to the gas engine 2 is started. The change of the operating condition in the gas engine 2 and the generator 11 was confirmed with respect to the case where the operation was stopped (test 2).
For comparison, in the power generation system 1 in which the first electromagnetic valve 63A and the second electromagnetic valve 63B are not provided, when the supply of the auxiliary fuel gas F2 to the gas engine 2 is started (comparison test 1), About the case where supply of sub fuel gas F2 to gas engine 2 was stopped (comparative test 2), it checked about change in the operating condition in gas engine 2 and generator 11.

In this confirmation test, the supply amount of the main fuel gas F1 to the gas engine 2, the supply amount of the auxiliary fuel gas F2 to the gas engine 2, and the generator 11 Measurements were made of changes in power generation output (electric power), air ratio in the gas engine 2 and NOx concentration.
Further, in this confirmation test, when the grid connection with the commercial power source 100 was performed, the supply of the auxiliary fuel gas F2 was started or stopped, and each data was measured.

  5, 7, 9, and 11, the horizontal axis represents time (seconds), and the vertical axis represents the supply amount of the main fuel gas F1, the supply amount of the auxiliary fuel gas F2, the power generation output of the generator 11, It is a graph which shows these changes at the time of the supply start of supply of sub fuel gas F2, or the stop of supply, taking loading pressure (kPa) of pressure regulator 61. Note that the supply amount of the main fuel gas F1, the supply amount of the auxiliary fuel gas F2, and the power generation output of the generator 11 are all expressed as a ratio (vs. rated%) to the rated value.

6, 8, 10, and 12, the horizontal axis represents time (seconds), and the vertical axis represents the air ratio and NOx concentration in the gas engine 2, so that the sub fuel gas F <b> 2 is supplied or It is a graph which shows these changes at the time of a supply stop. Note that the NOx concentration in the gas engine 2 is expressed as a ratio to the rated value (vs. rated%).
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.

  As shown in FIG. 5, when the supply of the auxiliary fuel gas F2 for test 1 is started, the loading pressure (kPa) of the pressure regulator 61 gradually increases immediately after the supply of the auxiliary fuel gas F2 is started, and the auxiliary fuel gas F2 is started. It can be seen that the supply amount of the main fuel gas F1 gradually decreases while the supply amount of the fuel gas gradually increases. It can be seen that the power generation output is stable although there is a slight fluctuation. In addition, as shown in FIG. 6, it can be seen that the air ratio and the NOx concentration are stable although there are slight fluctuations.

  Further, as shown in FIG. 7, when the supply of the auxiliary fuel gas F2 is stopped for the test 2, the loading pressure (kPa) of the pressure regulator 61 gradually decreases immediately after starting the supply of the auxiliary fuel gas F2, It can be seen that the supply amount of the auxiliary fuel gas F2 gradually decreases, while the supply amount of the main fuel gas F1 gradually increases. It can be seen that the power generation output is stable although there is a slight fluctuation. Further, as shown in FIG. 8, it can be seen that the air ratio and the NOx concentration are stable although there are slight fluctuations.

  As shown in FIG. 9, when the supply of the auxiliary fuel gas F2 for the comparative test 1 is started, immediately after the supply of the auxiliary fuel gas F2 is started, the supply amount of the auxiliary fuel gas F2 increases rapidly, while the main fuel gas F1 is increased. It can be seen that the supply amount of is decreasing rapidly. Then, it can be seen that the power generation output temporarily increases violently immediately after the supply of the auxiliary fuel gas F2 is started. Further, as shown in FIG. 10, it can be seen that the air ratio temporarily decreases (becomes rich in gas), and the NOx concentration temporarily increases dramatically.

  Further, as shown in FIG. 11, when the supply of the auxiliary fuel gas F2 for the comparative test 2 is stopped, the supply amount of the auxiliary fuel gas F2 rapidly decreases immediately after the stop of the supply of the auxiliary fuel gas F2 is started, It can be seen that the supply amount of the main fuel gas F1 increases rapidly. It can be seen that the power generation output temporarily decreases sharply immediately after the supply of the auxiliary fuel gas F2 is started. Further, as shown in FIG. 12, it can be seen that the air ratio temporarily increases (becomes gas lean), and the NOx concentration temporarily increases dramatically. The primary increase in the NOx concentration is considered to be because the throttle valve 51 is suddenly opened to temporarily reduce the air ratio in order to recover the temporary decrease in the power generation output.

  10 and 12, the change in the air ratio appears later than the supply start timing or supply stop timing of the auxiliary fuel gas F2 because of the measurement time lag (exhaust gas G is sucked This is because the air ratio is obtained by measuring the residual oxygen concentration and the like). Actually, it is considered that the change in the air ratio appears immediately after the supply of the auxiliary fuel gas F2 is started or immediately after the supply is stopped.

  Thus, according to the power generation system 1 that performs opening / closing control of the first electromagnetic valve 63A and the second electromagnetic valve 63B shown in the first embodiment, even when the grid connection with the commercial power source 100 is performed, It was found that the operation of the gas engine 2 can be stably maintained both when the supply of the auxiliary fuel gas F2 is started and when the supply is stopped.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. FIG. 3 is an explanatory diagram schematically showing a structure of a first mixer in the first embodiment. 3 is a flowchart illustrating a control operation of the power generation system in the first embodiment. Explanatory drawing which shows the electric power generation system in Example 2. FIG. The graph which shows the change of the supply amount of the main fuel gas at the time of the supply start of sub fuel gas, the supply amount of sub fuel gas, the power generation output of a generator, and the loading pressure of a pressure regulator about the test 1 in a confirmation test. The graph which shows the change of the air ratio and NOx density | concentration at the time of the supply start of sub fuel gas about the test 1 in a confirmation test. The graph which shows the change of the supply amount of the main fuel gas at the time of a supply stop of supply of sub fuel gas, the supply amount of sub fuel gas, the power generation output of a generator, and the loading pressure of a pressure regulator about the test 2 in a confirmation test. The graph which shows the change of the air ratio and NOx density | concentration at the time of the supply stop of sub fuel gas about the test 2 in a confirmation test. 6 is a graph showing changes in the amount of main fuel gas supplied, the amount of auxiliary fuel gas supplied, and the power generation output of the generator at the start of the supply of auxiliary fuel gas in Comparative Test 1 in the confirmation test. The graph which shows the change of the air ratio and NOx density | concentration at the time of the supply start of sub fuel gas about the comparative test 1 in a confirmation test. The graph which shows the change of the supply amount of the main fuel gas at the time of the supply stop of sub fuel gas, the supply amount of sub fuel gas, and the electric power generation output of a generator about the comparative test 2 in a confirmation test. The graph which shows the change of the air ratio and NOx density | concentration at the time of the supply stop of auxiliary fuel gas about the comparative test 2 in a confirmation test.

Explanation of symbols

DESCRIPTION OF SYMBOLS 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 611 Loading part 62 Sub fuel solenoid valve 63A 1st solenoid valve 63B Second solenoid valve 64A First loading pipe 64B Second loading pipe 65 Junction pipe 66 Restricted flow path section 7A First mixer 7B Second mixer 71 Venturi a Inlet section b Outlet section c Connection section 81 Control controller 82 Operation management controller A Combustion Air F1 Main fuel gas F2 Sub fuel gas M1 First mixture M2 Second mixture M3 Compressed mixture G Exhaust gas

Claims (7)

A gas engine with multiple cylinders;
A generator operated by the output of the gas engine;
An auxiliary fuel pipe to which an auxiliary fuel gas such as biogas is supplied;
A pressure regulator provided in the auxiliary fuel pipe;
An air pipe to which combustion air is supplied;
While the combustion air flowing from the air pipe can be passed, the pressure regulator is supplied from the sub fuel pipe according to the suction force generated when the combustion air flowing from the air pipe passes through the venturi. A first mixer capable of producing the first air-fuel mixture by mixing the sub fuel gas into the combustion air by the inflow of the sub fuel gas after the pressure is set by
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 controller that adjusts the opening of the throttle valve so that the power generation output of the generator becomes a target output;
The loading section for adjusting the outlet pressure of the pressure regulator is connected to the inlet section of the first mixer via a first loading pipe and connected to the outlet section of the first mixer via a second loading pipe. And
The first loading pipe is provided with a first solenoid valve, the second loading pipe is provided with a second solenoid valve, and the first solenoid valve and the second solenoid valve are operated by an operation management controller. Can be controlled to open and close,
When starting the operation of the gas engine, the operation management controller closes the first electromagnetic valve and opens the second electromagnetic valve so that the operation is performed using the main fuel gas. Yes,
When the supply of the auxiliary fuel gas to the gas engine is started, the operation management controller closes the second electromagnetic valve and opens the first electromagnetic valve, thereby opening the first mixer from the inlet of the first mixer. The combustion air is caused to flow into the first loading pipe to gradually increase the pressure at the loading portion of the pressure regulator, and the outlet pressure of the auxiliary fuel gas by the pressure regulator is changed to the combustion air at the inlet portion of the first mixer. It is configured to approach the pressure of
When stopping the supply of the auxiliary fuel gas to the gas engine, the first electromagnetic valve is closed and the second electromagnetic valve is opened by the operation management controller, whereby the first loading pipe is used to open the first electromagnetic valve. The combustion air is caused to flow out to the outlet of the mixer to gradually reduce the pressure in the loading part of the pressure regulator, and the outlet pressure of the auxiliary fuel gas by the pressure regulator is first mixed at the outlet of the first mixer. A power generation system configured to be close to the pressure of qi. The auxiliary fuel solenoid valve according to claim 1, wherein the auxiliary fuel pipe is provided with an auxiliary fuel solenoid valve that can be opened and closed by the operation management controller.
When starting the operation of the gas engine, the operation management controller is configured to close the auxiliary fuel solenoid valve and the first solenoid valve and open the second solenoid valve,
When the supply of the auxiliary fuel gas to the gas engine is started, the operation management controller opens the auxiliary fuel solenoid valve, closes the second electromagnetic valve, and opens the first electromagnetic valve. And
When the supply of the auxiliary fuel gas to the gas engine is stopped, the operation management controller closes the first electromagnetic valve and opens the second electromagnetic valve, and the pressure in the loading portion of the pressure regulator is A power generation system configured to close the sub-fuel solenoid valve by the operation management controller after the pressure of the first air-fuel mixture at the outlet of the first mixer becomes substantially the same. 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 pressure regulator provided in the auxiliary fuel pipe;
While the first air-fuel mixture flowing from the first mixer can be passed, the auxiliary fuel pipe is responsive to the suction force generated when the first air-fuel mixture flowing from the first mixer passes through the venturi. A second mixer capable of creating a second air-fuel mixture by mixing the sub-fuel gas into the first air-fuel mixture when the sub-fuel gas after pressure setting by the pressure regulator flows from
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 controller that adjusts the opening of the throttle valve so that the power generation output of the generator becomes a target output;
The loading section for adjusting the outlet pressure of the pressure regulator is connected to the inlet section of the second mixer via the first loading pipe, and is connected to the outlet section of the second mixer via the second loading pipe. And
The first loading pipe is provided with a first solenoid valve, the second loading pipe is provided with a second solenoid valve, and the first solenoid valve and the second solenoid valve are operated by an operation management controller. Can be controlled to open and close,
When starting the operation of the gas engine, the operation management controller closes the first electromagnetic valve and opens the second electromagnetic valve so that the operation is performed using the main fuel gas. Yes,
When the supply of the auxiliary fuel gas to the gas engine is started, the operation management controller closes the second electromagnetic valve and opens the first electromagnetic valve, thereby opening the first mixer from the inlet of the second mixer. The first air-fuel mixture is caused to flow into the first loading pipe to gradually increase the pressure at the loading portion of the pressure regulator, and the outlet pressure of the secondary fuel gas by the pressure regulator is changed to the first at the inlet portion of the second mixer. It is configured to approach the pressure of the mixture,
When stopping the supply of the auxiliary fuel gas to the gas engine, the operation management controller closes the first electromagnetic valve and opens the second electromagnetic valve, thereby opening the second loading pipe from the second loading pipe. The first air-fuel mixture is caused to flow out to the outlet of the mixer to gradually reduce the pressure in the loading portion of the pressure regulator, and the outlet pressure of the auxiliary fuel gas by the pressure regulator is changed to the second at the outlet of the second mixer. A power generation system configured to approach the pressure of an air-fuel mixture. The auxiliary fuel solenoid valve according to claim 3, wherein the auxiliary fuel pipe is provided with an auxiliary fuel solenoid valve that can be opened and closed by the operation management controller.
When starting the operation of the gas engine, the operation management controller is configured to close the auxiliary fuel solenoid valve and the first solenoid valve and open the second solenoid valve,
When the supply of the auxiliary fuel gas to the gas engine is started, the operation management controller opens the auxiliary fuel solenoid valve, closes the second electromagnetic valve, and opens the first electromagnetic valve. And
When the supply of the auxiliary fuel gas to the gas engine is stopped, the operation management controller closes the first electromagnetic valve and opens the second electromagnetic valve, and the pressure in the loading portion of the pressure regulator is A power generation system configured to close the sub fuel solenoid valve by the operation management controller after the pressure of the second air-fuel mixture at the outlet of the second mixer becomes substantially the same. In any one of Claims 1-4, the confluence | merging pipe | tube which the said 1st loading piping and the said 2nd loading piping joined is connected to the said loading part of the said pressure regulator, A throttle channel section having a smaller channel cross-sectional area than the first loading pipe and the second loading pipe is provided,
A power generation system configured to gradually increase or decrease the pressure in the loading portion of the pressure regulator by the throttle passage portion. 6. When the supply of the auxiliary fuel gas to the gas engine is started, the operation control controller opens the auxiliary fuel electromagnetic valve and the second electromagnetic valve is turned on. After closing, it is configured to gradually increase the pressure in the loading portion of the pressure regulator by repeatedly opening and closing the first electromagnetic valve,
When stopping the supply of the auxiliary fuel gas to the gas engine, the operation control controller closes the first electromagnetic valve, and then repeatedly opens and closes the second electromagnetic valve, whereby the pressure regulator A power generation system configured to gradually decrease the pressure in the loading portion. In any one of Claims 1-6, the said generator is comprised so that a load may be added when the power generation output is made to grid-connect with a commercial power source,
A power generation system configured to start and stop the supply of the auxiliary fuel gas to the gas engine when the power generation output of the generator is connected to the commercial power source.

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