JP2009062936A - Power generation system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a power generation system capable of stably performing fuel-mixing combustion operation with sub-fuel gas, when operating a gas engine by respectively injecting main fuel gas to intake pipes of a plurality of cylinders. <P>SOLUTION: This power generation system 1 operates a generator 11 by performing two-fuel-mixing combustion operation. The power generation system 1 supplies a compressed sub-fuel mixture M2 of the sub-fuel gas F2 and fuel air A after adjusting pressure by a sub-fuel pressure regulator 61 to the respective cylinders of the gas engine 2 via a supercharger 3, an air-fuel mixture adjusting valve 36 and an intake manifold 22, and supplies the main fuel gas F1 after adjusting pressure by a main fuel pressure regulator 52 to the respective cylinders 21 from respective main fuel injection valves 51. The power generation system 1 has a pressure control controller 82 for adjusting opening of the air-fuel mixture adjusting valve 36 so that pressure of the intake manifold 22 becomes target pressure, and an output control controller 81 for adjusting opening time of a plurality of main fuel injection valves 51 so that power generation output of the generator 11 becomes target output. <P>COPYRIGHT: (C)2009,JPO&INPIT

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, a method of adjusting the supply flow rate of an air-fuel mixture of main fuel gas and combustion air according to the calorific value of the auxiliary fuel gas, mixing two types of fuel, and burning, main fuel gas and auxiliary fuel gas There is a method of performing combustion while controlling the air ratio using the above mixed fuel.

  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, the negative pressure generated when combustion air passes through the mixer is used to suck the auxiliary fuel gas into the mixer to generate these air-fuel mixtures. The machine is operating.

Further, for example, in Patent Document 2, a mixed gas of main fuel gas such as waste gas and air is introduced into the main combustion chamber of the engine through the supply passage, and light oil or the like supplied into the sub chamber of the engine is used. A gas engine is disclosed in which an ignition flame is formed by auxiliary fuel, and the mixed gas is ignited and combusted by the ignition flame. In this gas engine, even if the calorific value of the main fuel gas is small or the calorific value of the main fuel gas fluctuates, stable ignition combustion is realized without being influenced by these.
Further, for example, in Patent Document 3, an injector that injects fuel gas is provided in an intake pipe that supplies an air-fuel mixture into the combustion chambers of a plurality of cylinders, and an air-fuel mixture injected by each injector is mixed with air. A gas engine that supplies gas to the combustion chamber of each cylinder is disclosed.

  However, in the conventional gas engine, in the system in which the main fuel gas such as city gas is injected into the intake pipes of a plurality of cylinders and the gas engine is operated, the co-firing operation with the auxiliary fuel gas is stably performed. Is not made.

JP 2005-30302 A JP 2005-171975 A JP 2006-105065 A

  The present invention has been made in view of such a conventional problem, and in a method of operating a gas engine by injecting a main fuel gas into intake pipes of a plurality of cylinders, a mixed combustion operation with a secondary fuel gas is stably performed. It is intended to provide a power generation system that can perform the above.

The present invention provides 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 secondary fuel pressure regulator provided in the secondary fuel pipe;
An air pipe to which combustion air is supplied;
According to the suction force generated when the combustion air flowing in from the air pipe passes through the venturi, the auxiliary fuel gas after the pressure is set by the auxiliary fuel pressure regulator flows in from the auxiliary fuel pipe. A secondary fuel mixer that mixes the secondary fuel gas with combustion air to create a secondary fuel mixture; and
Using the exhaust gas from the gas engine, compressing the auxiliary fuel mixture flowing in from the auxiliary fuel mixer to produce a compressed auxiliary fuel mixture;
An air-fuel mixture adjusting valve for adjusting the flow rate of the compressed sub-fuel mixture flowing from the supercharger;
An intake manifold for supplying the compressed sub fuel mixture after the flow rate adjustment by the mixture adjustment valve to be branched to the plurality of cylinders;
A main fuel pipe to which main fuel gas is supplied;
A main fuel pressure regulator provided in the main fuel pipe;
A main fuel manifold for supplying the main fuel gas after pressure adjustment by the main fuel pressure regulator to the plurality of cylinders;
A plurality of main fuel injection valves for injecting the main fuel gas branched by the main fuel manifold into the intake pipes of the plurality of cylinders;
A pressure controller for adjusting the opening of the air-fuel mixture adjustment valve so that the pressure in the intake manifold becomes a target pressure corresponding to the power generation output;
The power generation system further includes an output control controller that adjusts the open times of the plurality of main fuel injection valves so that the power generation output of the generator becomes a target output.

In the power generation system of the present invention, when the main fuel is operated alone using only the main fuel gas, the combustion air passes through the auxiliary fuel mixer, the supercharger, the air-fuel mixture adjusting valve, and the intake manifold, and the gas engine Is supplied to each cylinder.
The main fuel gas is set to a predetermined set outlet pressure by the main fuel pressure regulator and then supplied to each main fuel injection valve through the main fuel manifold. The output controller adjusts the opening time of each main fuel injection valve to control the supply amount of the main fuel gas to the gas engine so that the power generation output of the generator becomes a predetermined target output. The target output can be set as a predetermined output range.

  Further, the pressure controller adjusts the opening of the air-fuel mixture adjustment valve so that the pressure in the intake manifold becomes a target pressure corresponding to the power generation output. Thereby, the pressure in the intake manifold can be maintained at an appropriate target pressure commensurate with the magnitude of the power generation output. The target pressure can be set as a predetermined pressure range, and can be set as a larger value as the power generation output is larger.

The set outlet pressure of the main fuel pressure regulator is set to be higher than the pressure in the intake manifold. The set outlet pressure of the main fuel pressure regulator can be corrected according to the pressure level in the intake manifold. Specifically, by connecting the loading part of the main fuel pressure regulator to the intake manifold, when the pressure in the intake manifold decreases, the set outlet pressure of the main fuel pressure regulator is corrected low, while the pressure in the intake manifold increases. In this case, the set outlet pressure of the main fuel pressure regulator can be corrected to be high. Thereby, the pressure of the main fuel gas supplied to each main fuel injection valve can be maintained appropriately, and the control of the open time of each main fuel injection valve by the output controller can be stabilized.
The control by the output control controller, pressure control controller, main fuel pressure regulator, and the like are performed in the same manner when the two-fuel co-firing operation is performed.

  When performing a two-fuel co-firing operation using the main fuel gas and the sub fuel gas, combustion air is sucked into the sub fuel mixer according to the rotation speed of the supercharger, and the suction force generated thereby causes the sub fuel. The auxiliary fuel gas after the pressure is set by the auxiliary fuel pressure regulator flows into the fuel mixer. Then, in the auxiliary fuel mixer, an auxiliary fuel mixture of combustion air and auxiliary fuel gas is created, and the auxiliary fuel mixture passes through the supercharger, the air-fuel mixture adjusting valve, and the intake manifold, and each cylinder in the gas engine Supplied to.

In addition, as the output of the gas engine increases, the rotational speed of the supercharger increases, and the flow rate of combustion air sucked into the auxiliary fuel mixer and the flow rate of auxiliary fuel gas flowing into the auxiliary fuel mixer increase accordingly. Then, the flow rate of the compressed sub fuel mixture supplied to each cylinder in the gas engine increases through the supercharger, the mixture adjustment valve, and the intake manifold. And by supplementing the amount of heat that is insufficient so that the generator output becomes the target output with the main fuel gas, the amount of main fuel gas supplied to the gas engine The ratio with the supply amount of the auxiliary fuel gas can be kept substantially at the initially set ratio.
Further, since the pressure of the auxiliary fuel gas is set by the auxiliary fuel pressure regulator, the ratio of the amount of heat supplied to the gas engine to the auxiliary fuel gas can be kept below a predetermined ratio that allows stable operation at all times.

  In addition, the air ratio in the gas engine can be kept within an appropriate range by adjusting the opening of the air-fuel mixture adjustment valve by the pressure controller and adjusting the open time of each main fuel injection valve by the output controller. And increase in NOx and the like can be prevented. Thereby, even when the amount of heat of the auxiliary fuel gas changes due to the change in the composition of the auxiliary fuel gas, it is possible to prevent the air ratio in the gas engine from changing. Therefore, the power generation output of the generator can be stably maintained at the target output.

  Therefore, according to the power generation system of the present invention, in the method of operating the gas engine by injecting the main fuel gas into the intake pipes of the plurality of cylinders, the mixed combustion operation with the auxiliary fuel gas can be performed stably. .

A preferred embodiment of the present invention described above will be described.
In the present invention, 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 scrap, 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 addition, when the power generation system performs the main fuel single operation using only the main fuel gas, the pressure of the main fuel gas supplied to the plurality of main fuel injection valves is set by the main fuel pressure regulator. On the other hand, when the two-fuel co-firing operation is performed using the main fuel gas and the auxiliary fuel gas, the pressure of the main fuel gas supplied to the plurality of main fuel injection valves is set to the intake manifold. It is preferable to have a main fuel throttle means that makes the pressure higher than the pressure in the main fuel pressure regulator and lower than the set outlet pressure of the main fuel pressure regulator.

  In this case, when the two-fuel mixed combustion operation is performed, the supply amount of the main fuel gas to the gas engine can be stabilized even when the ratio of the auxiliary fuel gas in the entire fuel gas is increased. Specifically, when the two-fuel mixed combustion operation is performed, the opening time of each main fuel injection valve by the output control controller becomes shorter as the ratio of the auxiliary fuel gas in the entire fuel gas supplied to the gas engine is larger.

  Therefore, the main fuel throttle means sets the pressure of the main fuel gas supplied to each main fuel injection valve to a pressure higher than the pressure in the intake manifold and lower than the set outlet pressure of the main fuel pressure regulator. As a result, the pressure of the main fuel gas supplied from the main fuel pressure regulator to the main fuel injection valves through the main fuel manifold can be reduced. And the injection quantity of the main fuel gas injected when each main fuel injection valve is opened can be decreased. Therefore, even when the ratio of the auxiliary fuel gas in the entire fuel gas supplied to the gas engine is large, it is possible to prevent the opening time of each main fuel injection valve from becoming extremely short (opening each main fuel injection valve). A certain amount of time can be secured), and the supply amount of the main fuel gas to the gas engine necessary for setting the power generation output of the generator to the target output can be appropriately controlled.

  When the main fuel single operation is performed, the pressure at the outlet of the main fuel pressure regulator is not reduced by the main fuel throttle means, and the pressure of the main fuel gas supplied to each main fuel injection valve is It can be the set outlet pressure of the pressure regulator. Thereby, the opening time of each main fuel injection valve can be adjusted by the output controller, and the supply amount of the main fuel gas to the gas engine can be controlled appropriately.

The main fuel throttle means can be realized by the following various configurations.
For example, the main fuel throttle means connects a throttle pressure regulator provided on the downstream side of the main fuel pressure regulator in the main fuel pipe and a loading portion for adjusting a set outlet pressure of the throttle pressure regulator to the intake manifold. A second main fuel loading pipe connecting a first main fuel loading pipe, a first main fuel solenoid valve provided in the first main fuel loading pipe, a loading section of the throttle pressure regulator, and an inlet section of the throttle pressure regulator. It comprises a pipe and a second main fuel solenoid valve provided in the second main fuel loading pipe, and the first main fuel solenoid valve and the second main fuel solenoid valve can be controlled to be opened and closed by a main fuel management controller. The set outlet pressure in the throttle pressure regulator is higher than the pressure in the intake manifold. And when the main fuel pressure regulator is set to a pressure lower than the set outlet pressure in the main fuel pressure regulator and the main fuel single operation is performed, the main fuel management controller closes the first main fuel solenoid valve and By opening the two main fuel solenoid valves, the pressure of the main fuel gas supplied to the plurality of main fuel injection valves is set to the set outlet pressure of the main fuel pressure regulator, while the two fuel mixed combustion operation is performed. In this case, the main fuel gas supplied to the plurality of main fuel injection valves by opening the first main fuel solenoid valve and closing the second main fuel solenoid valve by the main fuel management controller. The pressure can be set to the set outlet pressure of the throttle pressure regulator.

  In this case, when the main fuel single operation is performed by the opening / closing control of the first main fuel solenoid valve and the second main fuel solenoid valve by the main fuel management controller, the main outlet pressure set by the main fuel pressure regulator is set. When supplying fuel gas to each main fuel injection valve and performing a two-fuel co-firing operation, the main fuel gas set at the set outlet pressure by the throttle pressure regulator is lower than the set outlet pressure by the main fuel pressure regulator. Supply to the fuel injection valve. As a result, when the two-fuel mixed combustion operation is performed, even when the ratio of the auxiliary fuel gas in the entire fuel gas supplied to the gas engine is large, the opening time of each main fuel injection valve is effectively shortened. Can be prevented.

  The main fuel throttle means includes a main fuel solenoid valve provided on the downstream side of the main fuel pressure regulator in the main fuel pipe, an inlet portion of the main fuel pressure regulator, and an outlet portion of the main fuel solenoid valve. A bypass pipe to be connected; a throttle pressure regulator provided in the bypass pipe; and a loading section for adjusting a set outlet pressure of the throttle pressure regulator, and an auxiliary main fuel loading pipe connected to the intake manifold, The solenoid valve can be opened and closed by the main fuel management controller, and the set outlet pressure in the throttle pressure regulator is set higher than the pressure in the intake manifold and lower than the set outlet pressure in the main fuel pressure regulator. However, when performing the main fuel single operation, the main fuel management controller is used. By opening the main fuel solenoid valve with a regulator, the pressure of the main fuel gas supplied to the plurality of main fuel injection valves is set to the set outlet pressure of the main fuel pressure regulator, while the two-fuel mixed combustion is performed. When the operation is performed, the main fuel solenoid valve is closed by the main fuel management controller, so that the pressure of the main fuel gas supplied to the plurality of main fuel injection valves is set to the setting outlet of the throttle pressure regulator. It can also be configured to be a pressure.

  In this case, the main fuel gas set to the set outlet pressure by the main fuel pressure regulator is sent to each main fuel injection valve when the main fuel is operated independently by the main fuel solenoid valve opening / closing control by the main fuel management controller. When the two-fuel mixed combustion operation is performed, the main fuel gas set at the set outlet pressure by the throttle pressure regulator, which is lower than the set outlet pressure by the main fuel pressure regulator, is supplied to each main fuel injection valve. As a result, when the two-fuel mixed combustion operation is performed, even when the ratio of the auxiliary fuel gas in the entire fuel gas supplied to the gas engine is large, the opening time of each main fuel injection valve is effectively shortened. Can be prevented.

  The loading unit for adjusting the outlet pressure of the auxiliary fuel pressure regulator is connected to the inlet of the auxiliary fuel mixer via a first auxiliary fuel loading pipe, and the auxiliary fuel is connected via a second auxiliary fuel loading pipe. Connected to the outlet of the mixer, the first sub fuel loading pipe is provided with a first sub fuel solenoid valve, the second sub fuel loading pipe is provided with a second sub fuel solenoid valve, and the first sub fuel solenoid valve is provided. The fuel solenoid valve and the second sub fuel solenoid valve can be controlled to be opened and closed by the sub fuel management controller. When starting the operation of the gas engine, the sub fuel management controller controls the first sub fuel solenoid valve. The main fuel single operation is performed with the second secondary fuel solenoid valve closed and the supply of the secondary fuel gas to the gas engine is started. The auxiliary fuel management controller closes the second auxiliary fuel solenoid valve and opens the first auxiliary fuel solenoid valve, thereby opening the first auxiliary fuel electromagnetic valve from the inlet portion of the auxiliary fuel mixer to the first auxiliary fuel loading pipe. Air is introduced to gradually increase the pressure at the loading portion of the auxiliary fuel pressure regulator so that the outlet pressure of the auxiliary fuel gas by the auxiliary fuel pressure regulator approaches the pressure of the combustion air at the inlet portion of the auxiliary fuel mixer. And when the supply of the sub fuel gas to the gas engine is stopped, the sub fuel management controller closes the first sub fuel solenoid valve and opens the second sub fuel solenoid valve. The combustion air is caused to flow out from the second auxiliary fuel loading pipe to the outlet of the auxiliary fuel mixer to regulate the auxiliary fuel pressure. It is preferable that the pressure at the loading portion of the gas generator is gradually reduced so that the outlet pressure of the auxiliary fuel gas by the auxiliary fuel pressure regulator approaches the pressure of the auxiliary fuel mixture at the outlet portion of the auxiliary fuel mixer. 3).

In this case, at the start and stop of the supply of the auxiliary fuel gas to the gas engine performing the two-fuel mixed combustion operation, the power generation output of the generator temporarily temporarily decreases or increases as follows. This can be prevented.
Specifically, when the power generation system is operated, the main fuel gas is used to close the main fuel with the first sub-fuel solenoid valve closed and the second sub-fuel solenoid valve opened by the sub-fuel management controller. Independent operation starts. The gas engine can be operated using only the main fuel gas until the output of the gas engine is stabilized by adjusting the opening time of each main fuel injection valve by the output controller.

  Next, when the supply of the auxiliary fuel gas is started (when the two-fuel co-firing operation is started), the auxiliary fuel management controller closes the second auxiliary fuel electromagnetic valve and opens the first auxiliary fuel electromagnetic valve to supply the auxiliary fuel to the gas engine. Start supplying gas. When the second auxiliary fuel solenoid valve is closed, the pressure at the loading portion of the auxiliary fuel pressure regulator is substantially the same as the pressure at the outlet portion of the auxiliary fuel mixer. When the first auxiliary fuel solenoid valve is opened, part of the combustion air passing through the air pipe gradually flows into the loading portion of the auxiliary fuel pressure regulator via the first auxiliary fuel loading pipe.

  As a result, the pressure (loading pressure) at the loading portion of the auxiliary fuel pressure regulator gradually increases, and the outlet pressure of the auxiliary fuel gas by the auxiliary fuel pressure regulator (the pressure of the auxiliary fuel gas at the outlet portion of the auxiliary fuel pressure regulator) is: Gradually increase to pressure at the inlet of the secondary fuel mixer. 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.

  On the other hand, when the supply of the auxiliary fuel gas is stopped (when the two-fuel co-firing operation is stopped), the auxiliary fuel management controller closes the first auxiliary fuel electromagnetic valve and opens the second auxiliary fuel electromagnetic valve, thereby supplying the gas engine. The supply of auxiliary fuel gas is stopped. When the first auxiliary fuel solenoid valve is closed, the pressure at the loading portion of the auxiliary fuel pressure regulator (loading pressure) is substantially the same as the pressure at the inlet portion of the auxiliary fuel mixer. When the second auxiliary fuel solenoid valve is opened, a part of the combustion air existing in the loading portion of the auxiliary fuel pressure regulator gradually passes to the outlet portion of the auxiliary fuel mixer via the second auxiliary fuel loading pipe. leak.

  Thereby, the pressure at the loading portion of the auxiliary fuel pressure regulator is gradually reduced, and the outlet pressure of the auxiliary fuel gas by the auxiliary fuel pressure regulator is gradually reduced to become the pressure at the outlet portion of the auxiliary fuel 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.

  The auxiliary fuel management controller performs opening / closing control of the first auxiliary fuel electromagnetic valve and the second auxiliary fuel electromagnetic valve, and does not control the opening degree. Therefore, the cost required for control can be kept low, and the control structure of the power generation system can be prevented from becoming complicated.

Below, it demonstrates with drawing about Examples 1-3 concerning the electric power generation system of this invention.
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 pressure regulator (differential pressure governor) 61 provided in the combustion chamber A and the combustion air A flowing in from the air pipe 4 are mixed with the auxiliary fuel gas F2 flowing in from the auxiliary fuel pipe 6 to create the auxiliary fuel mixture M1. And an auxiliary fuel mixer 7 capable of Further, the auxiliary fuel mixer 7 receives the auxiliary fuel after the pressure is set by the auxiliary fuel pressure regulator 61 from the auxiliary fuel pipe 6 in accordance with the suction force generated when the combustion air A flowing in from the air pipe 4 passes through the venturi 71. The gas F2 is configured to be sucked.

  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 F <b> 1 is supplied, a main fuel pressure regulator 52 provided in the main fuel pipe 5, and a pressure by the main fuel pressure regulator 52. The main fuel manifold 50 is supplied with the adjusted main fuel gas F1 branched to the plurality of cylinders 21. Corresponding to the plurality of cylinders 21, the main fuel gas F <b> 1 is supplied to the intake pipes of the respective cylinders 21 when the intake valves in the respective cylinders 21 are opened at the plurality of branched tip ends by the main fuel manifold 50. A plurality of main fuel injection valves 51 are provided for injecting each.

  Further, as shown in the figure, on the downstream side of the auxiliary fuel mixer 7, the exhaust gas G from the gas engine 2 is used for the intake pipe 12 through which the auxiliary fuel mixture M <b> 1 passes, and the auxiliary fuel mixer 7 flows in from the auxiliary fuel mixer 7. A supercharger 3 is provided that compresses the fuel mixture M1 to produce a compressed sub fuel mixture M2. On the downstream side of the supercharger 3 in the intake pipe 12, an air-fuel mixture adjustment valve 36 for adjusting the flow rate of the compressed sub fuel mixture M <b> 2 flowing from the supercharger 3 is provided. On the downstream side of the air-fuel mixture adjustment valve 36 in the intake pipe 12, an intake manifold 22 is provided that supplies the flow-adjusted sub fuel mixture M 1 flowing from the air-fuel mixture adjustment valve 36 to the plurality of cylinders 21. is there.

  As shown in FIG. 1, in the main fuel pressure regulator 52, a loading portion 521 that adjusts the set outlet pressure is connected to the intake manifold 22 by a main fuel loading pipe 55. The main fuel pressure regulator 52 is configured to correct the set outlet pressure low when the pressure in the intake manifold 22 decreases, and to correct the set outlet pressure high when the pressure in the intake manifold 22 increases. It is.

As shown in the figure, the generator 11 is provided with a wattmeter 811 for measuring the power generation output, and the intake manifold 22 has a pressure sensor 821 for measuring the pressure in the intake manifold 22. It is provided.
The power generation system 1 is a pressure control controller (computer) that performs feedback control by adjusting the opening of the air-fuel mixture adjustment valve 36 so that the pressure in the intake manifold 22 measured by the pressure sensor 821 becomes a target pressure corresponding to the power generation output. 82 and an output control controller (computer) 81 that performs feedback control by adjusting the open times of the plurality of main fuel injection valves 51 so that the power generation output of the generator 11 measured by the wattmeter 811 becomes the target output. is doing.
The output controller 81 can also adjust the opening times of the plurality of main fuel injection valves 51 so that the rotational speed of the gas engine 2 becomes the target rotational speed.

  As shown in FIG. 1, when the power generation system 1 performs the main fuel single operation using only the main fuel gas F1, the pressure of the main fuel gas F1 supplied to the plurality of main fuel injection valves 51 is changed to the main fuel pressure. On the other hand, when the two-fuel co-firing operation is performed using the main fuel gas F1 and the auxiliary fuel gas F2, the pressure of the main fuel gas F1 supplied to the plurality of main fuel injection valves 51 is set. The main fuel throttle means 500 has a pressure higher than the pressure in the intake manifold 22 and lower than the set outlet pressure of the main fuel pressure regulator 52.

Hereinafter, the power generation system 1 of this example will be described in detail with reference to FIGS.
As shown in FIG. 1, the main fuel injection valve 51 of this example can be controlled to open and close by an output controller 81, and while the intake valve in each cylinder 21 is open (during the intake process of each cylinder 21). ), An actuator such as an electromagnet is operated to inject the main fuel gas F1 for a predetermined time set according to the target output.
The air-fuel mixture adjusting valve 36 of this example receives a command from the pressure controller 82 and operates a valve body disposed at a passage port through which the compressed sub fuel mixture M2 passes by an actuator to open the passage port. It is configured to adjust the degree.
In addition, the auxiliary fuel mixer 7, the supercharger 3, the air-fuel mixture adjustment valve 36, and the intake manifold 22 are connected by an intake pipe 12.

  As shown in FIG. 2, the sub fuel mixer 7 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 are formed 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.

As shown in FIG. 1, 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 provided 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.

  In the auxiliary fuel pressure regulator 61 of this example, the loading portion 611 that adjusts the set pressure is downstream of the loading position of the air filter 41 in the air pipe 4 by the loading pipe 612 and is more than the auxiliary fuel mixer 7. Connected upstream. Then, the auxiliary fuel pressure regulator 61 is configured to correct the set pressure to be low in accordance with the decrease in the pressure of the combustion air A on the downstream side of the air filter 41 in the air pipe 4.

  The auxiliary fuel pressure regulator 61 is configured to set the set 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 set outlet pressure also increases. When the pressure applied to the loading unit 611 decreases, the set outlet pressure also decreases, and the pressure in the loading unit 611 (loading pressure). The total pressure of the pressure applied by the differential pressure adjusting spring and the set outlet pressure of the auxiliary fuel pressure regulator 61 are balanced.

By using the auxiliary fuel pressure regulator 61, the pressure of the combustion air A mixed in the auxiliary fuel mixer 7 and the pressure of the auxiliary fuel gas F2 can be kept substantially the same when the two-fuel mixed combustion operation is performed. The change in the mixing ratio can be reduced.
A main fuel pressure regulator 52 and a throttle pressure regulator 53, which will be described later, also have the same structure as the auxiliary fuel pressure regulator 61 (a structure having a loading portion 521 and a differential pressure adjusting spring).

As shown in FIG. 1, 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. The auxiliary fuel mixture M1 sent from the auxiliary fuel mixer 7 to the supercharger 3 is converted into a compressed auxiliary fuel mixture M2 by the compressor wheel 32 and supplied to the gas engine 2.
An air-fuel mixture cooler 35 is provided between the compressor wheel 32 of the supercharger 3 and the air-fuel mixture adjustment valve 36, and the air-fuel mixture adjustment valve 36 is connected to the intake manifold 22 after being cooled. The fuel mixture M2 is supplied.

As shown in FIG. 1, the main fuel throttle means 500 of this example includes a throttle pressure regulator 53 provided on the downstream side of the main fuel pressure regulator 52 in the main fuel pipe 5, and loading for adjusting the set outlet pressure of the throttle pressure regulator 53. A first main fuel loading pipe 56A connecting the part 531 to the intake manifold 22, a first main fuel electromagnetic valve 54A provided in the first main fuel loading pipe 56A, a loading part 531 of the throttle pressure regulator 53, and a throttle pressure regulator 53. The second main fuel loading pipe 56B that connects to the inlet of the second main fuel loading pipe 56B, and the second main fuel electromagnetic valve 54B provided in the second main fuel loading pipe 56B.
In this example, the first main fuel loading pipe 56A is joined to the main fuel loading pipe 55.

The first main fuel solenoid valve 54 </ b> A and the second main fuel solenoid valve 54 </ b> B can be controlled to open and close by a main fuel management controller (computer) 83. The set outlet pressure in the throttle pressure regulator 53 is set to be higher than the pressure in the intake manifold 22 and lower than the set outlet pressure in the main fuel pressure regulator 52.
When the main fuel single operation is performed, the power generation system 1 keeps the first main fuel solenoid valve 54A closed and the second main fuel solenoid valve 54B open by the main fuel management controller 83. The pressure of the main fuel gas F1 supplied to the main fuel injection valve 51 is set to the set outlet pressure of the main fuel pressure regulator 52. When the two-fuel co-firing operation is performed, the power generation system 1 opens the first main fuel solenoid valve 54A and closes the second main fuel solenoid valve 54B by the main fuel management controller 83. The pressure of the main fuel gas F 1 supplied to the main fuel injection valve 51 is set to the set outlet pressure of the throttle pressure regulator 53.

Further, in the power generation system 1, 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 equal to or less than the ratio initially set by the auxiliary fuel pressure regulator 61. Can be kept in.
Further, as shown in FIG. 1, a manual valve 68 can be disposed in the auxiliary fuel pipe 6 on the downstream side of the auxiliary fuel pressure regulator 61. When the power generation system 1 is initially set, the manual valve 68 can be operated to adjust the flow rate of the auxiliary fuel gas F2. Further, 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 auxiliary fuel pressure regulator 61.

  Further, the amount of heat supplied to the gas engine 2 of the auxiliary fuel gas F2 is within a range in which knocking can be prevented with respect to the total amount of heat supplied from 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. 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. Further, the ratio of the supply heat amount of the auxiliary fuel gas F2 to the supply heat amount of the entire fuel gas can be increased to, for example, about 90%.

In the power generation system 1 of the present example, in a method of operating the gas engine 2 by injecting the main fuel gas F1 such as city gas into the intake pipes of the plurality of cylinders 21, the mixed combustion with the auxiliary fuel gas F2 such as biogas is performed. Devised to stabilize driving. Further, in the power generation system 1 of the present example, even when the ratio of the auxiliary fuel gas F2 to the entire fuel gas (the whole of the main fuel gas F1 and the auxiliary fuel gas F2) increases, the main fuel gas F1 to the gas engine 2 is increased. To stabilize the supply amount.
In this example, when the main fuel single operation is performed using only the main fuel gas F1, the combustion air A is supplied from the auxiliary fuel mixer 7, the supercharger 3, the mixture cooler 35, and the mixture adjustment valve 36. And the intake manifold 22 is supplied to each cylinder 21 in the gas engine 2.

  The main fuel gas F <b> 1 is set to a predetermined set outlet pressure by the main fuel pressure regulator 52, and then supplied to each main fuel injection valve 51 through the main fuel manifold 50. Then, the output controller 81 adjusts the open time (open time) of each main fuel injection valve 51 when the intake valve of each cylinder 21 is opened, and supplies the main fuel gas F1 to the gas engine 2. The amount is adjusted, and feedback control is performed so that the power generation output of the generator 11 becomes a predetermined target output. The target output can be set as a predetermined output range.

  Further, the pressure controller 82 adjusts the opening of the air-fuel mixture adjustment valve 36 and performs feedback control so that the pressure in the intake manifold 22 becomes a target pressure corresponding to the power generation output. Thereby, the pressure in the intake manifold 22 can be maintained at an appropriate target pressure commensurate with the magnitude of the power generation output. The target pressure can be set as a predetermined pressure range, and can be set as a larger value as the power generation output is larger.

The set outlet pressure of the main fuel pressure regulator 52 is set as a pressure higher than the pressure in the intake manifold 22. The set outlet pressure of the main fuel pressure regulator 52 can be corrected according to the pressure level in the intake manifold 22. Specifically, since the loading portion 521 of the main fuel pressure regulator 52 is connected to the intake manifold 22, when the pressure in the intake manifold 22 decreases, the set outlet pressure of the main fuel pressure regulator 52 is corrected to be low. When the pressure in the intake manifold 22 increases, the set outlet pressure of the main fuel pressure regulator 52 can be corrected to be high. Thereby, the pressure of the main fuel gas F1 supplied to each main fuel injection valve 51 can be maintained appropriately, and the control of the open time of each main fuel injection valve 51 by the output controller 81 can be stabilized. .
Note that the control by the output controller 81, the pressure controller 82, and the main fuel pressure regulator 52 is performed in the same way when the two-fuel mixed combustion operation is performed.

  Further, when performing the main fuel single operation, the main fuel management controller 83 closes the first main fuel electromagnetic valve 54A and opens the second main fuel electromagnetic valve 54B. Then, the pressure in the intake manifold 22 is applied to the loading portion 521 of the main fuel pressure regulator 52, and the pressure at the outlet portion of the main fuel pressure regulator 52 is applied to the loading portion 531 of the throttle pressure regulator 53. Thereby, the pressure of the main fuel gas F1 supplied from the throttle pressure regulator 53 to each main fuel injection valve 51 can be set to the set outlet pressure of the main fuel pressure regulator 52 (the set outlet pressure of the main fuel pressure regulator 52). Can be almost the same). Therefore, the output controller 81 adjusts the time for opening each main fuel injection valve 51 when the intake valve in each cylinder 21 is open, and appropriately controls the supply amount of the main fuel gas F1 to the gas engine 2. be able to.

  Next, when the two-fuel mixed combustion operation is performed using the main fuel gas F1 and the auxiliary fuel gas F2, the combustion air A is sucked into the auxiliary fuel mixer 7 according to the rotational speed of the supercharger 3, The secondary fuel gas F2 after the pressure is set by the secondary fuel pressure regulator 61 flows into the secondary fuel mixer 7 by the suction force generated by the above. Then, in the auxiliary fuel mixer 7, an auxiliary fuel mixture M1 of the combustion air A and the auxiliary fuel gas F2 is created, and the auxiliary fuel mixture M1 includes the supercharger 3, the mixture cooler 35, and the mixture adjustment valve. 36 and the intake manifold 22 are supplied to each cylinder 21 in the gas engine 2.

Further, as the output of the gas engine 2 increases, the rotational speed of the supercharger 3 also increases. In accordance with this, the flow rate of the combustion air A sucked into the auxiliary fuel mixer 7 and the auxiliary fuel flowing into the auxiliary fuel mixer 7 are increased. The flow rate of the gas F2 increases and the compressed sub fuel mixture M2 supplied to each cylinder 21 in the gas engine 2 through the supercharger 3, the mixture cooler 35, the mixture adjustment valve 36, and the intake manifold 22 is supplied. The flow rate increases. Then, the main fuel gas F1 supplied to the gas engine 2 is supplied as long as the heat amount of the sub fuel gas F2 does not fluctuate by supplementing the amount of heat that is insufficient so that the power generation output of the generator 11 becomes the target output. The ratio between the supply amount of F1 and the supply amount of the auxiliary fuel gas F2 can be kept substantially at the initially set ratio.
Further, by setting the pressure of the auxiliary fuel gas F2 by the auxiliary fuel pressure regulator 61, the ratio of the heat quantity of the auxiliary fuel gas F2 supplied to the gas engine 2 is always kept below a predetermined ratio at which stable operation is possible. Can do.

Further, the opening degree of the air-fuel mixture adjustment valve 36 is adjusted by the pressure controller 82, and the opening time of each main fuel injection valve 51 is adjusted by the output controller 81, so that the air ratio in the gas engine 2 can be set within an appropriate range. The increase in NOx and the like can be prevented. Thereby, even when the amount of heat of the auxiliary fuel gas F2 changes due to a change in the composition of the auxiliary fuel gas F2, it is possible to suppress a change in the total amount of heat supplied to the gas engine 2. Therefore, the power generation output of the generator 11 can be stably maintained at the target output.
By the way, when the two-fuel mixed combustion operation is performed, each time the intake valve in each cylinder 21 is opened by the output controller 81, the larger the ratio of the auxiliary fuel gas F2 in the entire fuel gas supplied to the gas engine 2 is, The time for opening the main fuel injection valve 51 (open time for each main fuel injection valve 51) is shortened.

  Therefore, when performing the two-fuel mixed combustion operation, the main fuel management controller 83 opens the first main fuel solenoid valve 54A and closes the second main fuel solenoid valve 54B. The pressure in the intake manifold 22 is applied to the loading portion 531 of the throttle pressure regulator 53. Thereby, the pressure of the main fuel gas F1 supplied from the throttle pressure regulator 53 to each main fuel injection valve 51 is set to the set outlet pressure of the throttle pressure regulator 53 that is lower than the set outlet pressure of the main fuel pressure regulator 52. Can do.

  Thus, when performing the two-fuel mixed combustion operation, the pressure of the main fuel gas F1 supplied to each main fuel injection valve 51 can be lowered. And the injection quantity of the main fuel gas F1 injected when each main fuel injection valve 51 is opened can be decreased. Therefore, even when the ratio of the auxiliary fuel gas F2 in the entire fuel gas supplied to the gas engine 2 is large, the time during which the main fuel injection valve 51 is opened by the output controller 81 when the intake valve in each cylinder 21 is open. It is possible to prevent (the opening time of each main fuel injection valve 51) from becoming extremely short (the opening time of each main fuel injection valve 51 can be ensured to some extent). Further, it is possible to appropriately control the supply amount of the main fuel gas F1 to the gas engine 2 necessary for setting the power generation output of the generator 11 to the target output.

  Therefore, according to the power generation system 1 of this example, in the method of operating the gas engine 2 by injecting the main fuel gas F1 into the intake pipes of the plurality of cylinders 21, the mixed combustion operation with the auxiliary fuel gas F2 stably. It can be performed. Further, according to the power generation system 1 of this example, the supply amount of the main fuel gas F1 to the gas engine 2 can be stabilized even when the ratio of the auxiliary fuel gas F2 in the entire fuel gas is increased.

(Example 2)
In this example, when the supply of the auxiliary fuel gas F2 to the gas engine 2 that performs the two-fuel mixed combustion operation shown in the first embodiment is started and stopped, the power generation output of the generator 11 temporarily temporarily decreases or increases sharply. This is an example in which a device for preventing the occurrence of the problem is performed.
As shown in FIG. 3, the auxiliary fuel pipe 6 of this example is provided with an auxiliary fuel cutoff electromagnetic valve 62 that can open and close the auxiliary fuel pipe 6 on the downstream side of the auxiliary fuel pressure regulator 61. The auxiliary fuel shut-off solenoid valve 62 is in a state where the auxiliary fuel pipe 6 is always opened by the auxiliary fuel management controller 84 when the gas engine 2 performs the dual fuel co-firing operation. When the operation is performed, the auxiliary fuel management controller 84 closes the auxiliary fuel pipe 6.

Further, as shown in the figure, the loading portion 611 for adjusting the outlet pressure of the auxiliary fuel pressure regulator 61 is connected to the inlet portion a of the auxiliary fuel mixer 7 via the first auxiliary fuel loading pipe 64A. The secondary fuel loading pipe 64B is connected to the outlet b of the secondary fuel mixer 7.
The first sub fuel loading pipe 64A is provided with a first sub fuel electromagnetic valve 63A, and the second sub fuel loading pipe 64B is provided with a second sub fuel electromagnetic valve 63B. The auxiliary fuel cutoff electromagnetic valve 62, the first auxiliary fuel electromagnetic valve 63A, and the second auxiliary fuel electromagnetic valve 63B can be controlled to open and close by the auxiliary fuel management controller 84.

As shown in FIG. 3, in the power generation system 1, when starting the operation of the gas engine 2, the auxiliary fuel management controller 84 closes the auxiliary fuel cutoff electromagnetic valve 62 and the first auxiliary fuel electromagnetic valve 63 </ b> A and the second auxiliary fuel. With the electromagnetic valve 63B opened, 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 auxiliary fuel management controller 84 opens the auxiliary fuel cutoff electromagnetic valve 62 and closes the second auxiliary fuel electromagnetic valve 63B. Further, by opening the first auxiliary fuel electromagnetic valve 63A, the combustion air A is caused to flow from the inlet portion a of the auxiliary fuel mixer 7 into the first auxiliary fuel loading pipe 64A, and the pressure in the loading portion 611 of the auxiliary fuel pressure regulator 61 is increased. The outlet pressure of the auxiliary fuel pressure regulator 61 (supply pressure of the auxiliary fuel gas F2) is gradually increased so as to approach the pressure of the combustion air A at the inlet portion a of the auxiliary fuel mixer 7.

  Further, when the power generation system 1 stops the supply of the auxiliary fuel gas F2 to the gas engine 2, the auxiliary fuel management controller 84 closes the first auxiliary fuel electromagnetic valve 63A and opens the second auxiliary fuel electromagnetic valve 63B. As a result, the combustion air A flows out from the second auxiliary fuel loading pipe 64B to the outlet portion b of the auxiliary fuel mixer 7 to gradually reduce the pressure in the loading portion 611 of the auxiliary fuel pressure regulator 61. The outlet pressure (supply pressure of the auxiliary fuel gas F2) is made close to the pressure of the auxiliary fuel mixture M1 at the outlet portion b of the auxiliary fuel mixer 7.

As shown in FIG. 3, a merging pipe 65 in which the first sub fuel loading pipe 64A and the second sub fuel loading pipe 64B merge is connected to the loading portion 611 of the sub fuel 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 sub fuel loading pipe 64A and the second sub fuel 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.
The throttle channel 66 can gradually increase or decrease the pressure in the loading unit 611 of the auxiliary fuel pressure regulator 61. 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.

  It should be noted that the sub fuel management controller 84 provides the first sub fuel electromagnetic valve 63A (at the start of the supply of the sub fuel gas F2) or the second sub fuel together with the throttle channel portion 66 or instead of providing the throttle channel portion 66. Also by repeatedly opening and closing the electromagnetic valve 63B (when the supply of the auxiliary fuel gas F2 is stopped), the pressure in the loading portion 611 of the auxiliary fuel pressure regulator 61 is gradually increased (when the supply of the auxiliary fuel gas F2 is started) or It can be reduced (when the supply of the auxiliary fuel gas F2 is stopped). Then, the inflow speed of the combustion air A flowing into the loading portion 611 or the loading portion is increased by increasing the time during which the first auxiliary fuel electromagnetic valve 63A or the second auxiliary fuel electromagnetic valve 63B is open as time elapses. The outflow speed of the combustion air A flowing out from 611 can be set appropriately.

As shown in FIG. 3, the first auxiliary fuel loading pipe 64 </ b> A branching from the merging pipe 65 is downstream of the air filter 41 in the air pipe 4 and upstream of the auxiliary fuel mixer 7. Is connected to.
The second auxiliary fuel loading pipe 64B branched from the merging pipe 65 is connected to the intake pipe 12 between the auxiliary fuel mixer 7 and the supercharger 3.

  When the power generation system 1 of this example is operated, the sub fuel management controller 84 closes the sub fuel cutoff solenoid valve 62 and the first sub fuel solenoid valve 63A and opens the second sub fuel solenoid valve 63B. The operation of the gas engine 2 is started using only the main fuel gas F1 (step S101 in FIG. 4). Then, the frequency and voltage of the generator 11 are raised to the rated values (S102 in FIG. 4).

  Next, the auxiliary fuel management controller 84 opens the auxiliary fuel cutoff electromagnetic valve 62 and closes the second auxiliary fuel electromagnetic valve 63B, and then opens the first auxiliary fuel electromagnetic valve 63A to supply the auxiliary fuel gas F2 to the gas engine 2. Is started (S103 in FIG. 4). When the second sub fuel electromagnetic valve 63B is closed, the pressure at the loading portion 611 of the sub fuel pressure regulator 61 is substantially the same as the pressure at the outlet portion b of the sub fuel mixer 7. The converging pipe 65 where the first sub fuel loading pipe 64A joins is provided with a throttle passage portion 66, so that when the first sub fuel electromagnetic valve 63A is opened, the combustion pipe passing through the air pipe 4 is opened. A part of the air A gradually flows into the loading portion 611 of the auxiliary fuel pressure regulator 61 via the first auxiliary fuel loading pipe 64A.

  As a result, the pressure in the loading portion 611 of the auxiliary fuel pressure regulator 61 gradually increases, and the outlet pressure of the auxiliary fuel gas F2 by the auxiliary fuel pressure regulator 61 gradually becomes the pressure at the inlet portion a of the auxiliary fuel mixer 7. 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.

  The gas engine 2 performs a two-fuel co-firing operation, and the power generation system 1 can perform a load following operation so that the power generation output of the power generator 11 becomes a target output for driving a load on the power generator 11. Yes (S104 in FIG. 4). Next, when a stop signal is sent from the main management controller or the like of the power generation system 1 to the output control controller 81 and the pressure control controller 82 (S105 in FIG. 4), the output control controller 81 determines whether the main fuel injection valve 51 is open. The pressure controller 82 decreases the target pressure in the intake manifold 22 and decreases the power generation output of the generator 11 (S106 in FIG. 4).

  Next, the sub fuel management controller 84 closes the first sub fuel electromagnetic valve 63A and opens the second sub fuel electromagnetic valve 63B, thereby stopping the supply of the sub fuel gas F2 to the gas engine 2 ( (S107 in FIG. 4). When the first auxiliary fuel solenoid valve 63A is closed, the pressure at the loading portion 611 of the auxiliary fuel pressure regulator 61 is substantially the same as the pressure at the inlet portion a of the auxiliary fuel mixer 7. The converging pipe 65 where the second sub fuel loading pipe 64B joins is provided with a throttle passage section 66, so that when the second sub fuel electromagnetic valve 63B is opened, the loading section of the sub fuel pressure regulator 61 is opened. A part of the combustion air A present in 611 gradually flows out to the outlet b of the auxiliary fuel mixer 7 via the second auxiliary fuel loading pipe 64B.

  As a result, the pressure in the loading portion 611 of the auxiliary fuel pressure regulator 61 gradually decreases, and the outlet pressure of the auxiliary fuel gas F2 by the auxiliary fuel pressure regulator 61 gradually becomes the pressure at the outlet portion b of the auxiliary fuel mixer 7. Decrease. 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.

  Next, after the outlet pressure of the auxiliary fuel pressure regulator 61 becomes substantially the same as the pressure at the outlet b of the auxiliary fuel mixer 7 (the auxiliary fuel electromagnetic valve 63A is closed by the auxiliary fuel management controller 84 and the second auxiliary fuel electromagnetic valve is closed). After the valve 63B is opened and the timer set time elapses, the auxiliary fuel cutoff electromagnetic valve 62 can be closed by the auxiliary fuel management controller 84 to cut off the supply of the auxiliary fuel gas F2 to the gas engine 2 ( (S108 in FIG. 4).

Further, the auxiliary fuel management controller 84 performs open / close control (simple ON / OFF control) of the auxiliary fuel cutoff electromagnetic valve 62, the first auxiliary fuel electromagnetic valve 63A, and the second auxiliary fuel electromagnetic valve 63B. There is no control. The operation management controller 82 can be an inexpensive sequencer or the like. The first sub fuel loading pipe 64A and the second sub fuel loading pipe 64B have small pipe diameters (inner diameters), and small solenoid valves are used as the first sub fuel electromagnetic valve 63A and the second sub fuel electromagnetic valve 63B. be able to. Therefore, the cost required for controlling the power generation system 1 can be kept low, and the control structure of the power generation system 1 can be prevented from becoming complicated.
In addition, the configuration of the power generation system 1 of this example is the same as that of the first embodiment, and the same effects as those of the first embodiment can be obtained by the power generation system 1 of this example.

(Example 3)
This example is an example showing another configuration of the main fuel throttle means 500 in the power generation system 1 shown in the first embodiment.
As shown in FIG. 5, the main fuel throttle means 500 of this example includes a main fuel solenoid valve 54 provided downstream of the main fuel pressure regulator 52 in the main fuel pipe 5, an inlet portion of the main fuel pressure regulator 52, and the main fuel. Auxiliary main that connects the intake manifold 22 with a bypass pipe 57 that connects the outlet part of the solenoid valve 54, a throttle pressure regulator 53 provided in the bypass pipe 57, and a loading part 531 that adjusts the set outlet pressure of the throttle pressure regulator 53. And a fuel loading pipe 56. The main fuel solenoid valve 54 can be controlled to open and close by the main fuel management controller 83.
In this example, the auxiliary main fuel loading pipe 56 is joined to the main fuel loading pipe 55.

The set outlet pressure in the throttle pressure regulator 53 is set to be higher than the pressure in the intake manifold 22 and lower than the set outlet pressure in the main fuel pressure regulator 52.
In the power generation system 1 of this example, when the main fuel single operation is performed, the main fuel solenoid valve 54 is opened by the main fuel management controller 83, thereby supplying the main fuel to the plurality of main fuel injection valves 51. The pressure of the gas F <b> 1 is configured to be the set outlet pressure of the main fuel pressure regulator 52. Further, in the power generation system 1 of this example, when the two-fuel mixed combustion operation is performed, the main fuel electromagnetic valve 54 is closed by the main fuel management controller 83 so that the main fuel supplied to the plurality of main fuel injection valves 51 is maintained. The pressure of the gas F <b> 1 is configured to be the set outlet pressure of the throttle pressure regulator 53.

In this example, when the main fuel single operation is performed, the main fuel gas F1 flowing through the main fuel pipe 5 passes through the main fuel pressure regulator 52 having the higher set outlet pressure, and the set outlet pressure is higher than this. It cannot pass through the bypass pipe 57 provided with the low throttle pressure regulator 53. Thereby, the pressure of the main fuel gas F <b> 1 supplied to the plurality of main fuel injection valves 51 can be set to the set outlet pressure of the main fuel pressure regulator 52.
On the other hand, when the two-fuel mixed combustion operation is performed, the main fuel gas F1 flowing from the main fuel pipe 5 cannot pass through the main fuel pipe 5 through the main fuel pressure regulator 52, and the throttle pressure regulator Pass through the bypass pipe 57 through 53. Thereby, the pressure of the main fuel gas F <b> 1 supplied to the plurality of main fuel injection valves 51 can be set to the set outlet pressure of the throttle pressure regulator 53.

Therefore, even when the ratio of the auxiliary fuel gas F2 in the entire fuel gas supplied to the gas engine 2 is large, the time during which the main fuel injection valve 51 is opened by the output controller 81 when the intake valve in each cylinder 21 is open. It is possible to prevent (the opening time of each main fuel injection valve 51) from becoming extremely short.
In addition, the configuration of the power generation system 1 of this example is the same as that of the first embodiment, and the same effects as those of the first embodiment can be obtained by the power generation system 1 of this example.

FIG. 3 is an explanatory diagram illustrating a configuration of a power generation system in the first embodiment. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an explanatory diagram schematically showing a structure of a sub fuel mixer in Embodiment 1. Explanatory drawing which shows the structure of the electric power generation system in Example 2. FIG. 9 is a flowchart illustrating a control operation of the power generation system in the second embodiment. Explanatory drawing which shows the structure of the electric power generation system in Example 3. FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Power generation system 11 Generator 12 Intake pipe 2 Gas engine 21 Cylinder 22 Intake manifold 3 Supercharger 36 Mixture adjustment valve 4 Air pipe 5 Main fuel pipe 50 Main fuel manifold 500 Main fuel throttle means 51 Main fuel injection valve 52 Main fuel Pressure regulator 53 Throttle pressure regulator 54A First main fuel solenoid valve 54B Second main fuel solenoid valve 54 Main fuel solenoid valve 6 Sub fuel piping 61 Sub fuel pressure regulator 62 Sub fuel cutoff solenoid valve 63A First sub fuel solenoid valve 63B Second Sub fuel solenoid valve 7 Sub fuel mixer 81 Output control controller 82 Pressure control controller 83 Main fuel management controller 84 Sub fuel management controller A Combustion air F1 Main fuel gas F2 Sub fuel gas M1 Sub fuel mixture M2 Compressed sub fuel mixture

Claims (3)

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 secondary fuel pressure regulator provided in the secondary fuel pipe;
An air pipe to which combustion air is supplied;
According to the suction force generated when the combustion air flowing in from the air pipe passes through the venturi, the auxiliary fuel gas after the pressure is set by the auxiliary fuel pressure regulator flows in from the auxiliary fuel pipe. A secondary fuel mixer that mixes the secondary fuel gas with combustion air to create a secondary fuel mixture; and
Using the exhaust gas from the gas engine, compressing the auxiliary fuel mixture flowing in from the auxiliary fuel mixer to produce a compressed auxiliary fuel mixture;
An air-fuel mixture adjusting valve for adjusting the flow rate of the compressed sub-fuel mixture flowing from the supercharger;
An intake manifold for supplying the compressed sub fuel mixture after the flow rate adjustment by the mixture adjustment valve to be branched to the plurality of cylinders;
A main fuel pipe to which main fuel gas is supplied;
A main fuel pressure regulator provided in the main fuel pipe;
A main fuel manifold for supplying the main fuel gas after pressure adjustment by the main fuel pressure regulator to the plurality of cylinders;
A plurality of main fuel injection valves for injecting the main fuel gas branched by the main fuel manifold into the intake pipes of the plurality of cylinders;
A pressure controller for adjusting the opening of the air-fuel mixture adjustment valve so that the pressure in the intake manifold becomes a target pressure corresponding to the power generation output;
A power generation system comprising: an output controller that adjusts open times of the plurality of main fuel injection valves so that the power generation output of the generator becomes a target output.   The main fuel gas pressure supplied to the plurality of main fuel injection valves is set to a set outlet pressure of the main fuel pressure regulator when performing the main fuel single operation using only the main fuel gas. On the other hand, when the two-fuel mixed combustion operation is performed using the main fuel gas and the sub fuel gas, the pressure of the main fuel gas supplied to the plurality of main fuel injection valves is set to the pressure in the intake manifold. And a main fuel throttle means for making the pressure higher than the set outlet pressure of the main fuel pressure regulator. 3. The loading part for adjusting the outlet pressure of the auxiliary fuel pressure regulator according to claim 1, wherein the loading part is connected to the inlet part of the auxiliary fuel mixer via a first auxiliary fuel loading pipe. Connected to the outlet of the auxiliary fuel mixer via piping,
The first sub fuel loading pipe is provided with a first sub fuel solenoid valve, and the second sub fuel loading pipe is provided with a second sub fuel solenoid valve, and the first sub fuel solenoid valve and The second sub fuel solenoid valve can be opened and closed by a sub fuel management controller.
When starting the operation of the gas engine, the main fuel single operation is performed with the sub fuel management controller closing the first sub fuel solenoid valve and opening the second sub fuel solenoid valve. And
When the supply of the auxiliary fuel gas to the gas engine is started, the auxiliary fuel management controller closes the second auxiliary fuel electromagnetic valve and opens the first auxiliary fuel electromagnetic valve by the auxiliary fuel management controller. The combustion air is caused to flow into the first auxiliary fuel loading pipe from the inlet of the auxiliary fuel pressure regulator to gradually increase the pressure in the loading portion of the auxiliary fuel pressure regulator, and the outlet pressure of the auxiliary fuel gas by the auxiliary fuel pressure regulator is increased. It is configured to approach the pressure of combustion air at the inlet of the auxiliary fuel mixer,
When stopping the supply of the sub fuel gas to the gas engine, the sub fuel management controller closes the first sub fuel solenoid valve and opens the second sub fuel solenoid valve, thereby causing the second sub fuel solenoid valve to open. The combustion air is caused to flow out from the fuel loading pipe to the outlet portion of the auxiliary fuel mixer to gradually reduce the pressure in the loading portion of the auxiliary fuel pressure regulator, and the outlet pressure of the auxiliary fuel gas by the auxiliary fuel pressure regulator is set to the above. A power generation system configured to be close to the pressure of the auxiliary fuel mixture at the outlet of the auxiliary fuel mixer.

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