JP6008764B2 - Working gas circulation engine system - Google Patents

Description

  The present disclosure relates to a working gas circulation engine system in which a working gas containing argon circulates in a system from an exhaust part of an engine to an air supply part.

  2. Description of the Related Art Conventionally, there is known a working gas circulation type hydrogen engine system in which a working gas containing argon (hereinafter sometimes referred to as “Ar”) circulates in a system from an exhaust part of an engine to an air supply part. . For example, in the patent document 1, an invention relating to a hydrogen engine using argon as a working gas has been filed by the present applicant. Patent Document 2 discloses an invention relating to a working gas circulation type hydrogen engine using argon as a working gas.

These conventional hydrogen engine systems supply argon and oxygen (hereinafter sometimes referred to as “O ₂ ”) to the combustion chamber in place of air, so that argon expands due to heat generated by hydrogen combustion. Functions as a body (ie working gas). Argon discharged from the engine circulates in the system and is supplied again to the engine together with newly supplied oxygen. Thus, by using argon instead of nitrogen as the working gas, generation of nitrogen oxides (NOx) can be suppressed. In addition, since argon is a monoatomic molecular gas and has a high specific heat ratio, there is an advantage that an engine system having excellent thermal efficiency can be constructed.

Japanese Patent No. 3631891 JP 2006-77639 A

  By the way, diesel engines using heavy oil as fuel have been widely used for a long time, but gas engines that use natural gas as fuel as natural gas prices have fallen due to the recent rise in the price of heavy oil and the surreal gas revolution. Attention has been gathered. In addition, for example, in a marine main engine for imparting a propulsive force to a ship, natural gas is also used in addition to a gas engine or heavy oil that uses liquefied natural gas (LNG) as fuel in the recent trend of strengthening NOx regulations. An engine referred to as a so-called dual fuel engine that can be used as an engine has been put into practical use. In such an engine using heavy oil or natural gas as fuel, further improvement in thermal efficiency is expected.

  At least one embodiment of the present invention has been made in view of the current situation as described above. The object of the present invention is to achieve thermal efficiency in an engine using fuel containing carbon such as heavy oil and natural gas as fuel. It is to provide an engine system with excellent performance.

At least one embodiment of the present invention provides:
In a working gas circulation engine system in which working gas containing argon circulates in the system from the exhaust part to the supply part of the engine,
An engine that uses carbon-containing fuel as fuel,
A condenser for removing moisture in the combustion gas discharged from the engine;
A surplus gas discharger for discharging a part of the combustion gas discharged from the engine out of the system;
Carbon dioxide removal means for discharging carbon dioxide in the combustion gas discharged from the engine out of the system,
Oxygen supply means for supplying oxygen and argon contained in air outside the system into the system;
It is provided with.

According to the working gas circulation engine system, the oxygen gas supply means for supplying oxygen and argon contained in the outside air into the system is provided, and carbon dioxide (hereinafter referred to as carbon dioxide) in the combustion gas discharged from the engine. , And may be described as “CO ₂ ”). For this reason, carbon dioxide discharged from the engine can be discharged outside the system while maintaining oxygen and argon in the gas circulating in the system at a certain concentration or higher, such as heavy oil and natural gas that generate carbon dioxide during combustion This engine system can be suitably applied to an engine using a fuel containing carbon as a fuel, and the thermal efficiency of the engine can be greatly improved.

Further, according to the engine system using argon as a working gas, the thermal efficiency is improved not only at high load but also at low load. In this regard, the method of recovering exhaust gas energy with a turbo generator or the like by a turbocharger cannot effectively improve the thermal efficiency at low loads, and this system has a high advantage in this respect as well. .
Further, since argon is circulated and used as a working gas, there are advantages that almost no exhaust gas is discharged and that almost no NOx is generated during combustion of the engine.

In one embodiment of the present invention, the carbon dioxide removal means and the oxygen supply means are composed of separate devices configured separately from each other, and the carbon dioxide removal means includes the pressure of the combustion gas discharged from the engine and An adsorption CO ₂ removal device configured to adsorb and separate carbon dioxide in the combustion gas with an adsorbent and discharge it out of the system in an atmosphere in which at least one of the temperatures fluctuates; Separates oxygen and argon from the air by adsorbing nitrogen and carbon dioxide in the air to the adsorbent in an atmosphere in which at least one of the pressure and temperature of the air taken from outside the system fluctuates. It comprises an adsorptive O ₂ supply device configured to supply separated oxygen and argon into the system.
According to such an embodiment of the present invention, the carbon dioxide removing unit and the oxygen supplying unit described above are constituted by the adsorption-type CO ₂ removal device and the adsorption-type O ₂ supply device, respectively, so that the above-described thermal efficiency is excellent. This engine system can be realized.

In some embodiments, the adsorption O ₂ supply device is configured to supply oxygen and argon into the system downstream of the adsorption CO ₂ removal device.
According to this embodiment, compared with the case of supplying oxygen and argon, to reduce the gas flow rate supplied to the adsorption type CO ₂ removing device on the upstream side of the system than the adsorption CO ₂ removing device Therefore, the adsorption-type CO ₂ removal device can be made smaller accordingly.

In some embodiments, the adsorption-type CO ₂ removal device is disposed on the downstream side of the surplus gas discharger, and the remaining combustion gas excluding a part of the combustion gas discharged out of the system by the surplus gas discharger It is configured to be able to capture.
According to such an embodiment, as compared with the case where the adsorption-type CO ₂ removal device is arranged on the upstream side of the surplus gas discharger, the adsorption is performed by the amount of surplus gas discharged from the surplus gas discharger to the outside of the system. The flow rate of the gas supplied to the CO ₂ removal device can be reduced, and the adsorption CO ₂ removal device can be made smaller accordingly.

In some embodiments, a bypass path that bypasses the adsorption-type CO ₂ removal device is branched, and a flow rate control valve for controlling the flow rate of gas flowing through the bypass path is disposed.
In some embodiments, an air supply means for supplying air outside the system into the system without using an adsorption O ₂ supply device is provided upstream of the engine.

Increasing the argon concentration of the gas supplied to the engine (intake gas) increases the in-cylinder pressure and in-cylinder temperature during combustion and improves the thermal efficiency of the engine, but on the other hand, the in-cylinder pressure and in-cylinder temperature are reduced. If it is too high, problems will arise in the structure of the engine. For this reason, in practice, it is necessary to control the argon concentration of the gas supplied to the engine within an appropriate range.
According to the above-described embodiment, the flow rate of the combustion gas taken into the adsorption-type oxygen production device is controlled by adjusting the valve opening degree of the flow rate control valve, or the system is used without supplying the adsorption-type oxygen production device by the air supply means. By supplying outside air to the engine, the argon concentration of the supply gas can be controlled.

In some embodiments, at least one of the adsorption-type CO ₂ removal device and the adsorption-type O ₂ supply device is controlled by the supply gas in an atmosphere in which the temperature of the supply gas supplied to the device varies. While configured to adsorb and separate components, the energy of the combustion gas discharged from the engine can be used as energy for changing the temperature of the supply gas.
According to such an embodiment, the energy of the combustion gas discharged from the engine is effectively used to change the temperature of the supply gas, whereby the operation of the adsorption-type CO ₂ removal device and the adsorption-type O ₂ supply device is performed. Since the efficiency can be increased, the thermal efficiency of the engine system can be further improved.

In the above-described embodiment, a turbocharger having a turbine driven by combustion gas discharged from the engine, and a compressor that compresses a gas containing oxygen and argon that is arranged coaxially with the turbine and is supplied to the engine, and a compressor And an intercooler for cooling the gas compressed in step (b), and the heat medium heat-exchanged in the intercooler can be used as a heat source for changing the temperature of the supply gas.
Further, in the above embodiment, an air cooler for cooling the combustion gas exhausted from the engine is further provided, and the heat medium exchanged with the combustion gas in the air cooler varies the temperature of the supply gas. It can be configured to be usable as a heat source.
According to such an embodiment, the energy of the combustion gas discharged from the engine can be efficiently used for changing the temperature of the supply gas, and the thermal efficiency of the engine system can be further improved. .

In some embodiments, the apparatus further includes a liquefied fuel tank for storing the fuel gas supplied to the engine in a liquefied state, and at least one of the adsorption CO ₂ removal device and the adsorption O ₂ supply device is a gas It is configured to adsorb and separate the target gas in an atmosphere where the temperature varies, and the liquefied fuel gas can be used as a heat source for varying the gas temperature.
According to such an embodiment, the thermal efficiency of the engine system can be further improved by effectively using the liquefied fuel gas as a heat source for changing the gas temperature.

In another embodiment of the present invention, the carbon dioxide removal means and the oxygen supply means comprise one adsorption-type CO ₂ removal / O ₂ supply device configured integrally, and this adsorption-type CO ₂ removal / O _2. The supply device adsorbs and separates nitrogen and carbon dioxide in the air taken from outside the system in an atmosphere where the pressure and / or temperature fluctuates with an adsorbent and discharges it out of the system. Is supplied to the system, and combustion gas discharged from the engine can be taken in.
According to such another embodiment of the present invention, the above-described engine system can be simplified by configuring the above-described carbon dioxide removal means and oxygen supply means by one adsorption-type CO ₂ removal / O ₂ supply device. Can be realized with a simple configuration.

In some embodiments, an air supply valve for opening and closing the air supply port of the engine, and a control device that controls the operation timing of the air supply valve are further provided, and the control device dies the air supply valve. The compression ratio is configured to be lower than the expansion ratio by controlling to close the valve after the point.
As described above, the engine of the engine system in some embodiments is configured such that the compression ratio is lower than the expansion ratio by controlling the air supply valve so as to close after the bottom dead center. This is configured as a so-called Miller cycle engine. According to such an embodiment, since the in-cylinder pressure of the engine can be reduced, even when argon is used as the working gas, for example, the in-cylinder pressure can be reduced to a rated pressure or less.

  At this time, in a normal mirror cycle engine, there is a problem that the oxygen excess rate decreases and the engine output decreases as the amount of supplied gas decreases, but this engine system includes the above-described oxygen supply means. The oxygen supply rate can be adjusted by the oxygen supply means. Therefore, in this engine system, a decrease in engine output can be avoided by appropriately adjusting the oxygen excess rate.

In some embodiments, a turbocharger having a turbine driven by combustion gas exhausted from the engine, and a compressor disposed coaxially with the turbine and compressing a gas containing oxygen and argon supplied to the engine. Is further provided.
According to such an embodiment, it is possible to further improve the thermal efficiency of the entire engine system by driving the compressor with exhaust gas energy and compressing the gas containing oxygen and argon supplied to the engine.

In some embodiments, the engine is a direct injection engine configured to inject fuel directly from a fuel injector into a combustion chamber.
In this way, by configuring the engine in the engine system as a direct injection engine, the problem of knocking or pre-ignition that is a concern in the case of a port injection engine due to an increase in in-cylinder pressure or in-cylinder temperature is avoided. be able to.

In some embodiments, the engine is a gas engine that uses a fuel gas mainly composed of a hydrocarbon gas having 1 to 4 carbon atoms, and compresses the fuel gas in a combustion chamber to cause self-ignition. It is configured as a self-igniting gas engine.
The use of argon as the working gas increases the in-cylinder pressure and the in-cylinder temperature. For example, methane (CH ₄ ), ethane (C ₂ H ₆ ), propane (C ₃ H ₈ ), butane (C ₄ H ₁₀₎ The self-ignition can be achieved even when a fuel gas mainly composed of a hydrocarbon gas having 1 to 4 carbon atoms such as) is used. For this reason, it can comprise as a self-ignition type gas engine which does not use ignition sources, such as fuel oil and a spark plug as pilot fuel, and can improve thermal efficiency further.

In some embodiments, the engine is configured as a marine main engine for imparting propulsive force to the marine vessel.
The engine of the engine system is particularly preferably used as a marine main engine.

  According to at least one embodiment of the present invention, oxygen supply means for supplying oxygen and argon contained in air outside the system into the system is provided, and carbon dioxide in the combustion gas discharged from the engine is used. Since the carbon dioxide removing means for discharging to the outside is provided, it is possible to provide an engine system having excellent thermal efficiency in an engine using heavy oil or natural gas as fuel.

1 is a block diagram showing a schematic configuration of a working gas circulation engine system according to an embodiment of the present invention. 1 is a block diagram showing a schematic configuration of a working gas circulation engine system according to an embodiment of the present invention. 1 is a block diagram showing a schematic configuration of a working gas circulation engine system according to an embodiment of the present invention. 1 is a block diagram showing a schematic configuration of a working gas circulation engine system according to an embodiment of the present invention. 1 is a block diagram showing a schematic configuration of a working gas circulation engine system according to an embodiment of the present invention. 1 is a block diagram showing a schematic configuration of a working gas circulation engine system according to an embodiment of the present invention.

  Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. However, the dimensions, materials, shapes, relative arrangements, and the like of the components described in this embodiment are not intended to limit the scope of the present invention, but are merely illustrative examples.

FIG. 1 is a block diagram showing a schematic configuration of a working gas circulation engine system 1A according to an embodiment.
The engine system 1A is a circulating engine system in which a working gas containing argon circulates in the system, and is applied to, for example, a marine main engine for applying a propulsive force to a marine vessel.
As shown in FIG. 1, the engine system 1 </ _b > A includes an engine 10, a condenser 22, a surplus gas discharger 24, an adsorption CO ₂ removal device 25, an adsorption oxygen supply device 26, a control device 30, and an exhaust part of the engine 10. And a gas circulation path 20 that connects these devices in a ring shape.

  The engine 10 includes a cylinder 11, a piston 12 slidably accommodated inside the cylinder 11, an air supply valve 13 for opening and closing the air supply port 13a, an exhaust valve 14 for opening and closing the exhaust port 14a, and a combustion A fuel injection valve 16 for injecting fuel into the chamber 15, a fuel supplier 17 for supplying fuel to the fuel injection valve 16, a crankshaft 18, a connecting rod 19 for connecting the piston 12 and the crankshaft 18, etc. The

  The exhaust port 13 a is connected to the gas circulation path 20. Then, by opening the supply valve 13, argon and oxygen circulating in the gas circulation path 20 are supplied from the supply port 13 a to the combustion chamber 15 as supply gas. The air supply gas supplied to the combustion chamber 15 is compressed in the combustion chamber 15 as the piston 12 rises, thereby increasing the in-cylinder temperature and the in-cylinder pressure in the combustion chamber 15. When the piston 12 reaches near the top dead center, the fuel is directly injected from the fuel injection valve 16 into the combustion chamber 15. The injected fuel self-ignites in a high temperature atmosphere and explodes in the combustion chamber 15. Then, the argon gas (working gas) pushes down the piston 12 due to the expansion accompanying the explosion, thereby rotating the crankshaft 18 via the connecting rod 19. The combustion gas after the explosion is discharged to the gas circulation path 20 connected to the exhaust port 14a by opening the exhaust valve 14.

  As the fuel, a fuel containing carbon, that is, a fuel other than hydrogen, for example, a fuel gas such as natural gas or petroleum gas, or a fuel oil such as heavy oil or light oil can be used. Fuel gas such as natural gas or petroleum gas is mainly composed of hydrocarbon gas having 1 to 4 carbon atoms such as methane, ethane, propane and butane, and is usually stored in a liquefied state.

  The condenser 22 is a device for condensing and removing moisture in the combustion gas discharged from the engine 10, and is installed on the downstream side of the engine 10. The water condensed in the condenser 22 is removed out of the system.

  The surplus gas discharger 24 is a device for discharging a part of the combustion gas sent from the condenser 22 to the outside of the system and sending the remaining combustion gas downstream. Since oxygen or argon contained in the air is supplied into the system from the adsorption type oxygen supply device 26 to be described later, an amount corresponding to the increment of the supplied gas amount is discharged out of the system in advance as surplus gas. It is a device for. The amount of surplus gas discharged from the surplus gas discharger 24 is about 1% of the total amount of combustion gas.

  The adsorption-type carbon dioxide removing device 25 is a carbon dioxide removing means for discharging carbon dioxide in the combustion gas discharged from the engine 10 to the outside of the system, and air is discharged by a method such as a so-called PSA (Pressure Swing Adsorption) method. This device removes carbon dioxide. The adsorption-type carbon dioxide removing device 25 is disposed on the downstream side of the surplus gas discharger 24 in the gas annular path 20, and a residual gas excluding a part of the combustion gas discharged out of the system from the surplus gas discharger 24. Combustion gas is supplied.

The adsorption-type oxygen supply device 26 is an oxygen supply means for supplying oxygen and argon contained in the air outside the system into the system. Like the adsorption-type carbon dioxide removal device 25, the adsorption-type oxygen supply device 26 is a PSA method or the like. It is an apparatus that adsorbs and separates oxygen and argon from air outside the system by a method and supplies the separated oxygen and argon into the system. The adsorption-type O ₂ supply device 26 is configured to be able to take in air outside the system, and supplies oxygen and argon into the system downstream of the adsorption-type CO ₂ removal device 25. Further, the combustion gas flowing through the gas annular path 20 does not flow into the adsorption O ₂ supply device 26.

Each of the adsorption-type carbon dioxide removing device 25 and the adsorption-type oxygen supply device 26 includes an adsorption tank filled with an adsorbent.
In the adsorption-type carbon dioxide removing device 25, the combustion gas discharged from the engine 10 is sent to the adsorption tank. Then, the carbon dioxide in the combustion gas is adsorbed and separated by the adsorbent by changing the pressure of the combustion gas in the adsorption tank.
Further, in the adsorption oxygen supply device 26, air taken from outside the system is sent to the adsorption tank. And the nitrogen and carbon dioxide in air are made to adsorb | suck to adsorption agent by fluctuating the pressure of combustion gas in an adsorption tank, and oxygen and argon are isolate | separated from the air.

  The adsorption-type carbon dioxide removal device 25 and the adsorption-type oxygen supply device 26 are not limited to devices using the PSA method, that is, a method of adsorbing and separating the target gas by changing the pressure in the adsorption tank. TSA (Thermal Swing Adsorption) method that adsorbs and separates the target gas by changing the temperature in the tank, and PTSA (Pressure and Thermal Swing Adsorption) that adsorbs and separates the target gas by changing the temperature and pressure in the adsorption tank It may be a device by a law or the like.

  As these adsorption-type carbon dioxide removal device 25 and adsorption-type oxygen supply device 26, those known as devices by the PSA method, TSA method, and PTSA method can be used.

  The control device 30 is configured by a computer such as an engine control unit, and includes a CPU (Central Processing Unit), a memory, an input / output device, and the like. And it is comprised so that the operation timing of the air supply valve 13 and the exhaust valve 14 of the engine 10 mentioned above can be controlled by transmitting the operation signal regarding valve opening / closing timing.

  According to the working gas circulation engine system 1A according to at least one embodiment of the present invention configured as described above, as described above, oxygen and argon contained in air outside the system are supplied into the system. And an oxygen supply device 26 (oxygen supply means) and a carbon dioxide removal device 25 (carbon dioxide removal means) for discharging carbon dioxide in the combustion gas discharged from the engine 10 out of the system. For this reason, since carbon dioxide discharged from the engine 10 can be discharged out of the system while maintaining oxygen and argon in the gas circulating in the system at a certain concentration or higher, heavy oil and natural gas that generate carbon dioxide during combustion For example, the engine system 1A can be suitably applied to the engine 10 that uses carbon-containing fuel such as the fuel, and the thermal efficiency of the engine 10 can be greatly improved.

  Further, according to the engine system 1A using argon as a working gas, the thermal efficiency is improved not only at a high load but also at a low load. In this regard, the method of recovering exhaust gas energy with a turbo generator by a turbocharger cannot effectively improve the thermal efficiency at low loads, and this system 1A also has a high advantage in this respect. Yes.

Further, since argon is circulated and used as a working gas, there are advantages that almost no exhaust gas is emitted and that almost no NOx is generated during combustion of the engine 10.
Further, by employing the adsorption-type carbon dioxide removing device 25 as the carbon dioxide removing means, nitrogen can be separated along with the carbon dioxide. For this reason, the concentration of argon circulating in the system can be increased, and the thermal efficiency of the engine system 1A can be further increased.

In one embodiment of the present invention, as described above, the carbon dioxide removal means and the oxygen supply means are composed of separate devices configured separately from each other. That is, the carbon dioxide removing means adsorbs and separates carbon dioxide in the combustion gas with an adsorbent in an atmosphere in which at least one of the pressure and temperature of the combustion gas discharged from the engine 10 fluctuates. consists adsorptive formula CO ₂ removing device 25 configured to discharge, the oxygen supply means, in an atmosphere of at least one of pressure and temperature of the air taken in from the outside of the system is varied, the oxygen in the air and It consists of an adsorption type O ₂ supply device 26 configured to adsorb and separate argon with an adsorbent and supply it into the system.
According to such an embodiment of the present invention, the carbon dioxide removing means and the oxygen supplying means described above are constituted by the adsorption CO ₂ removal device 25 and the adsorption O ₂ supply device 26, respectively, thereby improving the thermal efficiency. The above-described engine system 1A can be realized.

In some embodiments, as described above, the adsorption-type O ₂ supply device 26 is configured to supply oxygen and argon into the system downstream of the adsorption-type CO ₂ removal device 25.
According to this embodiment, as compared with the case of supplying oxygen and argon on the upstream side of the system than the adsorption CO ₂ removing device 25, reducing the flow rate of the gas supplied to the adsorption type CO ₂ remover 25 Therefore, the adsorption-type CO ₂ removal device can be made smaller by that amount.

In some embodiments, as described above, the adsorption-type CO ₂ removal device 25 is disposed on the downstream side of the surplus gas discharger 24, and a part of the exhaust gas discharged from the system by the surplus gas discharger 24 is used. The remaining combustion gas excluding the combustion gas can be taken in.
According to such an embodiment, surplus gas is discharged out of the system from the surplus gas discharger 24 as compared with the case where the adsorption-type CO ₂ removal device 25 is disposed upstream of the surplus gas discharger 24. The gas flow rate supplied to the adsorption-type CO ₂ removal device 25 can be reduced by that amount, and the adsorption-type CO ₂ removal device 25 can be made smaller by that amount.

In some embodiments, a bypass path that bypasses the adsorption-type CO ₂ removal device is branched, and a flow rate control valve for controlling the flow rate of gas flowing through the bypass path is disposed.
In some embodiments, an air supply means for supplying air outside the system into the system without using an adsorption O ₂ supply device is provided upstream of the engine.

In some embodiments, as shown in FIG. 1, the engine system 1A includes a turbocharger that includes a turbine 32, a compressor 32b disposed coaxially with the turbine 32, and a rotor 32c that connects the turbine 32 and the compressor 32b. A machine 32 is further provided.
The turbine 32a is disposed downstream of the engine 10, and the compressor 32b is disposed downstream of the point where oxygen and argon are supplied from the adsorption oxygen supply device 26 into the system. When the turbine 32a is driven by the combustion gas discharged from the engine 10, the compressor 32b is coaxially driven accordingly. Then, the compressor 32b compresses the gas containing oxygen and argon supplied from the adsorption oxygen supply device 26 into the system, and supplies the compressed gas to the engine 10 as a supply gas. An intercooler 34 for cooling the supply gas supplied to the engine 10 is disposed downstream of the compressor 32b.

  As described above, if the engine system 1A includes the supercharger 32, the compressor 32b is driven by the exhaust gas energy, and the gas containing oxygen and argon supplied to the engine 10 is compressed. Thermal efficiency can be further improved.

In some embodiments, as described above, the air supply valve 13 for opening and closing the air supply port 13a of the engine 10 and the control device 30 for controlling the operation timing of the air supply valve 13 are further provided. And this control apparatus 30 is comprised so that a compression ratio may fall rather than an expansion ratio by controlling the air supply valve 13 so that it may delay and close from a bottom dead center.
As described above, the engine 10 of the engine system 1A is configured so that the compression ratio is lower than the expansion ratio by controlling the air supply valve 13 to be closed after being delayed from the bottom dead center. Configured as a mirror cycle engine. According to such an embodiment, since the in-cylinder pressure of the engine 10 can be reduced, even when argon is used as the working gas, for example, the in-cylinder pressure can be reduced to a rated pressure or less. .

At this time, in the normal mirror cycle engine, there is a problem that the oxygen excess rate decreases and the engine output also decreases as the amount of supplied gas decreases, but this engine system 1A has the above-described adsorption-type O ₂ supply device. (Oxygen supply means) is provided, and the oxygen excess rate can be adjusted by the adsorption-type O ₂ supply device. Therefore, in this engine system 1A, a decrease in engine output can be avoided by adjusting the oxygen excess rate as appropriate.

FIG. 2 is a block diagram illustrating a schematic configuration of a working gas circulation engine system 1B according to an embodiment.
In the engine system 1B shown in FIG. 2, a bypass path 35 that bypasses the adsorption-type CO ₂ removal device 25 is branched downstream of the surplus gas discharger 24 with respect to the engine system 1A described above. A flow control valve 36 for controlling the flow rate of the gas flowing through the engine 10, and for supplying air outside the system to the engine 10 upstream of the engine 10 without passing through the adsorption-type O ₂ supply device 26. The difference is that an air supply means 38 is provided.

Here, the installation position of the air supply means 38 is not particularly limited as long as it is a position where air outside the system can be supplied to the engine 10 without going through the adsorption type oxygen generator 26. Since the lower pressure in the gas circulation path 20 is more advantageous for supplying air, it is preferable that the pressure in the upstream side of the compressor 32b.
Also, the better to the downstream side of the adsorption type CO ₂ removing device 25, it is possible to reduce the gas flow path to be supplied to the adsorption type CO ₂ removing device 25, preferably.

  Increasing the argon concentration of the gas (supply gas) supplied to the engine 10 increases the in-cylinder pressure and the in-cylinder temperature during combustion and improves the thermal efficiency of the engine 10, but on the other hand, the in-cylinder pressure and in-cylinder If the temperature rises too much, problems will arise in the structure of the engine 10. For this reason, in practice, it is necessary to control the argon concentration of the gas supplied to the engine 10 within an appropriate range.

For such a problem, according to the engine system 1B, the flow rate of the combustion gas taken into the adsorption-type CO ₂ removal device 25 is controlled by adjusting the valve opening degree of the flow control valve 36, or the air supply means By supplying the air outside the system to the engine 10 without using the adsorption type O ₂ supply device 26 by 38, the argon concentration of the supply gas can be controlled.

FIG. 3 is a block diagram illustrating a schematic configuration of a working gas circulation engine system 1C according to an embodiment.
In the engine system 1C shown in FIG. 3, at least one of the adsorption CO ₂ removal device 25 and the adsorption O ₂ supply device 26 described above is in an atmosphere in which the temperature of the supply gas supplied to the device varies. The apparatus is configured as a TSA method or PTSA method device for adsorbing and separating a target component from a supply gas. Further, the engine system 1C exchanges heat with the liquefied fuel tank 42 for storing the fuel gas such as natural gas in a liquefied state and the fuel gas in the liquefied state with the heat medium, with respect to the engine system 1A described above. The heat exchanger 44 that is vaporized in this way, and the heat medium circulation path 46 for circulating the heat medium between the heat exchanger 44 and the adsorption-type CO ₂ removal device 25 are different. .

When the heat medium cooled by the heat exchange in the heat exchanger 44 is supplied to the adsorption type CO ₂ removing device 25, the adsorption CO ₂ removing device 25 with the supplied feed gases (excess gas discharging device 24 The supplied combustion gas) is cooled. That is, the engine system 1C is configured to use the liquefied fuel gas as a cooling heat source for changing the temperature of the supply gas supplied to the adsorption-type CO ₂ removal device 25. By configuring in this way, the operating efficiency of the adsorption-type CO ₂ removal device 25 can be increased, so that the thermal efficiency of the engine system 1C can be further improved.

The engine system 1C further includes a second heat medium circulation path 48 for circulating the heat medium between the intercooler 34 and the adsorption O ₂ supply device 26 with respect to the engine system 1A described above. Is different.
In the intercooler 34, heat exchange is performed between the supply gas compressed by the compressor 32b and heated to a heat medium such as cooling water. Then, by heat medium heated by the heat exchanger is supplied to the adsorption type O ₂ supply device 26, so that the supply gas supplied to the adsorption type O ₂ supply device 26 (the outside of the system of air) is heated It is configured. That is, the engine system 1C is configured to use the energy of the combustion gas discharged from the engine 10 as energy for changing the temperature of the supply gas supplied to the adsorption O2 supply device 26.

Further, the engine system 1C includes an air cooler 37 for cooling the combustion gas discharged from the engine 10 between the turbine 32a and the condenser 22, and an air cooler. A difference is that a third heat medium circulation path 50 for circulating the heat medium is further provided between the air-conditioner 37 and the adsorption CO ₂ removal device 25.
In the air cooler 37, heat exchange is performed between the combustion gas discharged from the engine 10 and a heat medium such as cooling water. Then, by heat medium heated by the heat exchanger is supplied to the adsorption type CO ₂ removing device 25, the combustion gas supplied from the adsorption type CO ₂ removing device 25 with the supplied feed gases (excess gas discharging device 24 ) Is heated.

In the engine system 1C of this embodiment, the energy of the combustion gas discharged from the engine 10 is used as energy for changing the temperature of the supply gas supplied to the adsorption O2 supply device 26. Since the operation efficiency of the adsorption O ₂ supply device 26 can be increased, the thermal efficiency of the engine system 1C can be further improved.

In addition, the utilization form of the energy of the liquefied fuel gas and the combustion gas described above is not limited to the aspect shown in FIG. 3, and it is needless to say that various changes can be made. Further, for example, the heat energy of the combustion gas recovered through the heat medium in the condenser 22 can be supplied to the adsorption CO ₂ removal device 25 or the adsorption O 2 supply device 26.

In another embodiment of the present invention, as shown in FIGS. 4 to 6, the carbon dioxide removal means and the oxygen supply means are provided from one adsorption-type CO ₂ removal / O ₂ supply device 27 configured integrally. Become. This adsorption-type CO ₂ removal / O ₂ supply device 27 is a system in which nitrogen and carbon dioxide in the air taken from outside the system are adsorbed and separated by an adsorbent in an atmosphere in which at least one of pressure and temperature varies. The system is configured to discharge outside and supply a gas containing the remaining oxygen and argon into the system. Further, the adsorption type CO ₂ removal / O ₂ supply device 27 is arranged on the downstream side of the surplus gas discharger 24 in the gas circulation path 20, and is configured to be able to take in the combustion gas discharged from the engine 10 described above. Has been.
4 corresponds to FIG. 1 of the above embodiment, FIG. 5 corresponds to FIG. 2 of the above embodiment, and FIG. 6 corresponds to FIG. 3 of the above embodiment.

According to such another embodiment of the present invention, the above-described engine systems 1D to 1F are configured by configuring the carbon dioxide removing unit and the oxygen supply unit described above by one adsorption-type CO ₂ removal / O ₂ supply unit 27. Can be realized with a simple configuration.

In some embodiments, the engine 10 may be a direct injection engine configured to inject fuel directly from the fuel injection valve 16 into the combustion chamber 15.
As described above, by configuring the engine 10 in the engine systems 1A to 1F as a direct injection engine, it is possible to avoid the problems of knocking and pre-ignition that are a concern in the case of a premixed engine.

Further, in some embodiments, the engine 10 is a gas engine 10 that uses a fuel gas mainly composed of a hydrocarbon gas having 1 to 4 carbon atoms, and compresses the fuel gas in the combustion chamber 15. It can be configured as a self-ignition gas engine that self-ignites.
As described above, the use of argon as the working gas increases the in-cylinder pressure and the in-cylinder temperature. For example, methane (CH ₄ ), ethane (C ₂ H ₆ ), propane (C ₃ H ₈ ), butane Even when a fuel gas mainly composed of a hydrocarbon gas having 1 to 4 carbon atoms such as (C ₄ H ₁₀ ) is used, self-ignition can be performed. For this reason, it can comprise as a self-ignition type gas engine which does not use ignition sources, such as fuel oil and a spark plug as pilot fuel, and it becomes possible to raise thermal efficiency further.

  As mentioned above, although embodiment of this invention was described in detail, it cannot be overemphasized that this invention is not limited to this, In the range which does not deviate from the summary of this invention, various improvement and deformation | transformation may be performed.

  The working gas circulation engine system according to at least one embodiment of the present invention is suitably used in various engine systems, for example, an engine system of a marine main engine for imparting propulsive force to a ship.

1A to 1F Engine system 10 Engine 11 Cylinder 12 Piston 13 Air supply valve 13a Air supply port 14 Exhaust valve 14a Exhaust port 15 Combustion chamber 16 Fuel injection valve 17 Fuel supply 18 Crankshaft 19 Connecting rod 20 Gas circulation path 22 Condenser 24 Surplus Gas exhauster 25 Adsorption type CO ₂ removal device (carbon dioxide removal means)
26 Adsorption O ₂ supply device (oxygen supply means)
27 Adsorption-type CO ₂ removal device / O ₂ supply device (carbon dioxide removal means / oxygen supply means)
30 ECU (control device)
32 Supercharger 32a Turbine 32b Compressor 32c Rotor 34 Intercooler 35 Bypass path 36 Flow control valve 37 Air cooler 38 Air supply means 42 Liquefied fuel tank 44 Heat exchanger 46 Heat medium circulation path 48 Second heat medium circulation path 50 3 Heat medium circuit

Claims (14)

In a working gas circulation engine system in which working gas containing argon circulates in the system from the exhaust part to the supply part of the engine,
An engine that uses carbon-containing fuel as fuel,
A condenser for removing moisture in the combustion gas discharged from the engine;
A surplus gas discharger for discharging a part of the combustion gas discharged from the engine out of the system;
Carbon dioxide removal means for discharging carbon dioxide in the combustion gas discharged from the engine out of the system,
Oxygen supply means for supplying oxygen and argon contained in air outside the system into the system;
Equipped with a,
A working gas circulation engine system, characterized in that a bypass passage that bypasses the carbon dioxide removing means branches and a flow rate control valve for controlling a flow rate of gas flowing through the bypass passage is disposed . The carbon dioxide removal means and the oxygen supply means are composed of separate apparatuses configured separately from each other,
The carbon dioxide removing means adsorbs and separates carbon dioxide in the combustion gas with an adsorbent and discharges it outside the system in an atmosphere in which at least one of the pressure and temperature of the combustion gas discharged from the engine fluctuates. Comprising an adsorption-type CO ₂ removal device configured to
The oxygen supply means is configured to adsorb nitrogen and carbon dioxide in the air to the adsorbent in an atmosphere in which at least one of pressure and temperature of air taken from outside the system fluctuates, so that oxygen and argon are extracted from the air. The working gas circulation engine system according to claim 1, further comprising an adsorption type O ₂ supply device configured to supply the separated oxygen and argon into the system. The working gas circulation according to claim 2, wherein the adsorption type O ₂ supply device is configured to supply oxygen and argon into a system downstream of the adsorption type CO ₂ removal device. Type engine system. The adsorption-type CO ₂ removal device is arranged on the downstream side of the surplus gas discharger, and is configured to be able to take in the remaining combustion gas excluding a part of the combustion gas discharged out of the system by the surplus gas discharger The working gas circulation engine system according to claim 2, wherein the working gas circulation engine system is provided. Upstream of the engine, any claim 2 to 4, characterized in that air supply means for supplying the outside of the system of air into the system without passing through the adsorption-type O ₂ supply device is provided The working gas circulation engine system according to claim 1. At least one of the adsorption-type CO ₂ removal device and the adsorption-type O ₂ supply device adsorbs and separates the target component from the supply gas in an atmosphere in which the temperature of the supply gas supplied to the device varies. while being configured, the energy of the combustion gas discharged from the engine, either one of claims 2 to 5, characterized in that it is configured to be utilized as energy for varying the temperature of the feed gas The working gas circulation engine system according to one item. An air cooler for cooling the combustion gas discharged from the engine;
The working gas circulation type according to claim 6 , wherein the heat medium exchanged with the combustion gas in the air cooler can be used as a heat source for changing the temperature of the supply gas. Engine system. A liquefied fuel tank for storing the fuel gas supplied to the engine in a liquefied state;
At least one of the adsorption-type CO ₂ removal device and the adsorption-type O ₂ supply device adsorbs and separates the target component from the supply gas in an atmosphere in which the temperature of the supply gas supplied to the device varies. while being configured to, according to the fuel gas in the liquefied state, to any one of claims 2 to 7, characterized in that it is configured to be utilized as a heat source for varying the temperature of the feed gas Working gas circulation engine system. The carbon dioxide removal means and the oxygen supply means are composed of one adsorption-type CO ₂ removal / O ₂ supply device configured integrally,
The adsorption-type CO ₂ removal / O ₂ supply device is configured to adsorb and separate nitrogen and carbon dioxide in the air taken from outside the system with an adsorbent in an atmosphere in which at least one of pressure and temperature varies. The working gas circulation according to claim 1, wherein a gas containing residual oxygen and argon is supplied into the system, and combustion gas discharged from the engine can be taken in. Type engine system. An air supply valve for opening and closing the air supply port of the engine, and a control device for controlling the operation timing of the air supply valve,
2. The control device according to claim 1, wherein the control device is configured to lower the compression ratio than the expansion ratio by controlling the air supply valve to close after being delayed from the bottom dead center. 9 working gas circulation engine system according to any one of. A turbine driven by combustion gas discharged from the engine;
It is disposed in the turbine and coaxial to any one of claims 1 to 10, further comprising a turbocharger having a compressor for compressing a gas containing oxygen and argon is supplied to the engine The working gas circulation engine system described. The working gas circulation engine system according to any one of claims 1 to 11 , wherein the engine is a direct injection engine configured to inject fuel directly from a fuel injection valve into a combustion chamber. . The engine is a gas engine that uses a fuel gas whose main component is a hydrocarbon gas having 1 to 4 carbon atoms, and is configured as a self-ignition gas engine that compresses the fuel gas in a combustion chamber and self-ignites it. The working gas circulation engine system according to any one of claims 1 to 12 , wherein the working gas circulation engine system is provided. The working gas circulation engine system according to any one of claims 1 to 13 , wherein the engine is configured as a marine main engine for applying a propulsive force to a marine vessel.

Images