JP3484931B2 - Gas engine with natural gas reformer - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gas engine equipped with a natural gas reforming device for reforming a gas fuel such as natural gas as a fuel with the heat energy of exhaust gas to improve thermal efficiency.

[0002]

2. Description of the Related Art Conventionally, a gas engine using natural gas as a main fuel has been developed as a cogeneration system. In a cogeneration system, power is taken out by a generator as electric energy, heat of exhaust gas energy is heated by a heat exchanger to make hot water, and the hot water is used for hot water supply. Conventionally, as an engine using natural gas as fuel, for example, Japanese Patent Laid-Open No. 6-1088
65 and Japanese Patent Laid-Open No. 6-101495.

The cogeneration type gas engine disclosed in Japanese Unexamined Patent Publication No. 6-108865 lowers the temperature of exhaust gas through a turbocharger, an energy recovery device and a steam generator, and cools the exhaust gas to a low temperature.
It is used for GR to reduce NO _X , exhaust gas from a heat shield type gas engine drives a turbocharger, and exhaust gas from the turbocharger drives an energy recovery device equipped with a generator. The cogeneration gas engine sends exhaust gas from an energy recovery device to a steam generator of a heat exchanger, converts water into steam by the steam generator, and drives the steam turbine with the steam to recover electric energy. To do.

[0004]

In a gas engine using natural gas as a fuel, if the combustion chamber is constructed with a heat shield structure made of a material such as ceramics, the compression temperature of air rises above the self-ignition temperature of natural gas. ， No need for ignition device,
In addition to the main chamber that introduces air, a sub chamber that introduces fuel is provided, and a control valve is provided between the main chamber and the sub chamber to provide a highly efficient engine for cogeneration by a diesel cycle operation. can do. The exhaust gas of a gas engine becomes a high temperature of 850 ° C. or higher when the combustion chamber has a heat shield structure. The thermal energy of the engine can be improved by recovering heat energy from the hot exhaust gas.

By the way, it is known that the main component of natural gas is methane CH ₄ . CH ₄ of fuel is
Since it has a large calorific value and is abundant in nature, it is expected as a future alternative fuel for oil. In addition, CH ₄ is CO
_When pyrolyzed via a catalyst in the presence of ₂ , CH ₄
Is converted to CO (carbon monoxide) and H ₂ (hydrogen),
The total calorific value of CO and H ₂ is greater than that of CH ₄ , that is, 1.38 times. Therefore, the heat energy of the high-temperature exhaust gas of the heat shielded gas engine is utilized for the thermal decomposition of CH ₄ to reform the natural gas into the reformed fuel, thereby increasing the heat generation of the reformed fuel, It is possible to improve thermal efficiency, save resources, and suppress CO ₂ emission.

[0006]

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems, and the main component of natural gas is CH.
₄ for modifying the gas, by utilizing the heat energy of the exhaust gas by mixing CO ₂ with the aid of a catalyst modified in the CO and H ₂ in CH _4, the CO ₂ at that time the engine discharged exhaust It secures the gas from the gas through a separation membrane to improve the thermal efficiency and to utilize the CO ₂ in the exhaust gas for reforming the CO ₂
While reducing the emission, it is to provide a gas engine with a natural gas reforming device that reduces the occurrence of NO _X.

[0007] The present invention, a fuel tank containing a natural gas fuel mainly composed of CH _4, the reforming fuel by thermal decomposition by the exhaust gas discharged from the combustion chamber CH ₄ supplied from the fuel tank A catalytic reactor arranged in an exhaust passage for conversion, a reformed fuel supply device for supplying the reformed fuel to the combustion chamber, a turbocharger provided in the exhaust passage downstream of the catalytic reactor, the turbocharger First-stage heat exchanger provided in the exhaust passage of the downstream flow, a steam turbine driven by steam generated in the first-stage heat exchanger, and a condenser for converting steam discharged from the steam turbine into water A second stage heat exchanger provided in the exhaust passage downstream of the first stage heat exchanger and converting water sent from the condenser into steam and supplying the steam to the first stage heat exchanger. Exchanger, and the CO ₂ supply the said from the exhaust gas to separate CO ₂ and CO ₂ by the CO ₂ separation membrane provided in the exhaust passage of the flow after the second stage heat exchanger to the catalytic reactor The present invention relates to a gas engine equipped with a natural gas reforming device including a supply device.

The CO ₂ separation membrane is made of alumina, silica,
It is composed of an inorganic separation membrane made of zeolite-based porous ceramics. The CO ₂ separation membrane is composed of a porous membrane in which fine open holes are formed in ceramics,
For example, by utilizing the fact that the molecular diameter of CO ₂ is smaller than that of N ₂ or O ₂ , CO ₂ can be separated from the exhaust gas by utilizing the molecular sieving effect, and the operating temperature is 350 ° C.
Therefore, it can be effectively applied to the present invention.

The catalytic reactor is composed of a catalyst device having a heat exchange action, and has a surface coated with an exhaust gas passage through which the exhaust gas flows and the catalyst incorporated inside a partition wall of the exhaust gas passage. The gas fuel passage accommodates the porous member. In addition, the catalytic reactor uses Ni or Pt as a catalyst to generate CH ₄
And CO ₂ are reacted to thermally decompose CO and H ₂ .

C which did not contribute to the thermal decomposition of CH ₄
O ₂ is supplied to the combustion chamber together with the reformed fuel. Since the mixed gas of CH ₄ , CO, H ₂ , and CO ₂ is introduced into the sub chamber of the combustion chamber, the control valve is opened and the mixed gas of the sub chamber is fed to the combustion chamber. When mixed with compressed air in the main chamber and burned, NO due to the presence of CO ₂
Generation of _X is suppressed, and generation of NO _X can be suppressed to 100 ppm or less.

The first-stage heat exchanger includes a steam passage in which a porous ceramic member in which the steam heated by the second-stage heat exchanger arranged in the first casing flows is disposed, and the steam passage. And an exhaust gas passage, through which the exhaust gas flows, in which a porous ceramic member is arranged.

The second-stage heat exchanger is arranged in a second casing provided adjacent to the first casing, and a porous ceramic member through which steam flows is arranged. And an exhaust gas passage arranged around the water / steam passage and in which a porous ceramic member through which the exhaust gas from the first stage heat exchanger flows is arranged.

A fuel nozzle for injecting the reformed fuel from the catalytic reactor is provided in the exhaust passage on the upstream side of the first stage heat exchanger.

Further, since a fuel nozzle for injecting a part of the reformed fuel from the catalytic reactor is provided in the exhaust passage on the upstream side of the first stage heat exchanger, A small amount of injected fuel burns with O ₂ contained in the exhaust gas and generates heat and is sent to the first stage heat exchanger, so the enthalpy of the exhaust gas increases and the efficiency of the steam turbine is improved. be able to.

Further, in the gas engine provided with this natural gas reforming device, the combustion chamber is constructed in a heat shield structure by a ceramic member. That is, by forming the wall surface of the combustion chamber from a ceramic member and forming a heat shield layer on the outer side thereof, the combustion chamber can be configured as a heat shield structure. Therefore,
The gas engine is hot exhaust gas in the exhaust gas is about 900 ° C. discharged from the combustion chamber, will be discharged into the exhaust passage the hot exhaust gases from the combustion chamber, CH ₄ and CO _With the help of a catalyst, the mixed gas with ₂ is thermally decomposed and converted into CO and H ₂ , which can improve the thermal efficiency.

In the gas engine equipped with this natural gas reforming apparatus, if the combustion chamber has a heat shield structure with a ceramic member in the above structure, the temperature of the exhaust gas discharged from the combustion chamber is, for example, In the catalytic reactor, the temperature is about 900 ° C to 800 ° C, which can sufficiently contribute to the thermal decomposition of CH ₄ , and is then recovered by the turbocharger to be lowered by about 150 ° C. Then, in the first stage heat exchanger. It is recovered and lowered by about 200 ° C., and finally recovered by the second stage heat exchanger and lowered by about 200 ° C. Accordingly, the exhaust gas temperature of the CO ₂ separation device is 350 ° C to 25 ° C.
The exhaust gas reduced to about 0 ° C. is supplied, and CO ₂ can be satisfactorily separated from the exhaust gas in the CO ₂ separation device. That is, since the CO ₂ separation membrane is a ceramic porous body, it has excellent heat resistance, and is most activated at about 300 ° C., so that CO ₂ can be separated from the exhaust gas well.

Further, since the high-temperature steam generated by the first-stage heat exchanger and the second-stage heat exchanger drives the steam turbine, an energy recovery device comprising a gas turbine as in the conventional case is provided. Compared with the above, it is not necessary to raise the inlet pressure to the first stage heat exchanger as in the gas turbine. That is, the rise in the inlet pressure of the gas turbine directly increases the back pressure in the exhaust stroke of the reciprocating engine, which causes a large loss.

As described above, the gas engine equipped with this natural gas reforming apparatus uses the steam turbine to generate high-pressure steam with the exhaust gas energy without raising the back pressure, and to generate electric energy. Since it is converted, the thermal efficiency can be improved. Furthermore, if the steam turbine is a radial turbine, it can be made smaller and less expensive than an axial flow turbine.

Since the gas engine equipped with this natural gas reforming apparatus is constructed as described above, CO ₂ is mixed with CH ₄ which is the main component of natural gas, and the heat energy of the exhaust gas is converted into heat by the aid of the catalyst. Since it is decomposed and converted into reformed fuels CO and H ₂ , the heat generation amount can be increased by about 38%, and the thermal efficiency of the engine can be improved.
The above decomposition reaction is performed by CH ₄ and CO on a catalyst such as Ni or Pt.
_This is a reaction in which thermal decomposition occurs when a mixed gas of ₂ is passed and heated to about 800 ° C. or higher, CO ₂ is decomposed into carbon monoxide, and CH ₄ is decomposed into CO and H ₂ . Also, by configuring the combustion chamber with a heat shield structure, the exhaust gas from the combustion chamber will be in a high temperature state, and the exhaust gas temperature will be 800 ° C or higher,
The thermal decomposition reaction can be smoothly achieved.

Since the gas engine equipped with this natural gas reforming apparatus is constructed as described above, if the thermal efficiency of the gas engine by the diesel cycle is 42%, the thermal efficiency will be improved by the turbocharger equipped with the generator. Approximately 8% improvement, thermal efficiency is improved by about 5% by steam turbine, and the heat generation amount is 1.38 times by thermally decomposing CH ₄ into CO and H ₂ , so the thermal decomposition rate of CH ₄ is 5
At 0%, a thermal efficiency of 65.5% can be expected for the entire gas engine.

[0021]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of a gas engine having a natural gas reforming apparatus according to the present invention will be described below with reference to the drawings. 1 is an explanatory view showing an embodiment of a gas engine equipped with a natural gas reforming apparatus according to the present invention, FIG. 2 is an explanatory view showing a turbocharger equipped with a generator incorporated in the gas engine of FIG. 1, and FIG. 3 is an explanatory view showing a steam turbine incorporated in the gas engine of FIG.

A gas engine equipped with this natural gas reforming apparatus is a single-cylinder or multi-cylinder engine that uses a gas body such as natural gas as a fuel and can be applied to a cogeneration system. A combustion chamber is formed in the cylinder. Main room 1
A sub-chamber gas engine is composed of A and a sub-chamber 1B formed in a cylinder head 30 communicating with the main chamber 1A through a communication port. The gas engine 1 is the main chamber 1A of the combustion chamber.
An exhaust manifold 39 for exhausting exhaust gas from the
An intake manifold 40 is provided to supply intake air to the main chamber 1A through the intake passage 10. The intake air from the intake passage 10 is supplied to the main chamber 1A of each cylinder through the intake manifold 40, and the exhaust gas from each main chamber 1A is collected by the exhaust manifold 39 and discharged to the exhaust passage 8. Further, the reformed fuel obtained by reforming the natural gas supplied to the sub-chamber 1B is supplied to each sub-chamber 1B of the combustion chamber through the reformed fuel supply passage 9 by the operation of the fuel pressurizing pump 13.

In this embodiment, the main chamber 1A and the sub chamber 1B of the combustion chamber of the gas engine 1 are constructed as a heat shield structure by a ceramic member, a heat shield layer and the like. The gas engine 1 includes a sub chamber 1B formed in a cylinder head 30 to which reformed fuel is supplied, and the sub chamber 1B is configured to communicate with the main chamber 1A by opening a communication port by a control valve 31. ing. Compressed air from the compressor 16 of the turbocharger 3 is supplied to the main chamber 1A through the intake passage 10, and a fuel valve 32 is provided in the sub chamber 1B, which is modified by opening the fuel supply port by the fuel valve 32. The reformed fuel is supplied from the quality fuel supply passage 9 to the sub chamber 1B.

The gas engine 1 is particularly equipped with a natural gas reforming device, and CH _{4 of} natural gas is generated by the heat energy of the exhaust gas discharged from the main chamber 1A through the exhaust passage 8.
An exhaust passage 8 is provided with a catalytic reactor 2 that converts CO ₂ into reformed fuel in the presence of CO ₂ . A turbocharger 3 driven by exhaust gas is provided in an exhaust passage 8 downstream of the catalytic reactor 2. The gas engine 1 includes a fuel tank 11 containing a natural gas fuel containing CH ₄ as a main component,
A fuel pressurizing pump 13 and a turbocharger 3 which constitute a reformed fuel supply device for supplying the reformed fuel to the sub chamber 1B of the combustion chamber.
The first stage heat exchanger 4, which is provided in the exhaust passage 8A in the downstream of
Steam turbine 5 driven by steam generated in the first-stage heat exchanger 4, exhaust passage 8B in the wake of the first-stage heat exchanger 4
The second stage heat exchanger 6, which supplies the first stage heat exchanger 4 with the fluid (low temperature steam and water) which is provided in the steam turbine 5 and is discharged from the steam turbine 5 to the first stage heat exchanger 4, and the second stage heat. Exchanger 6
Is provided in the exhaust passage 8C downstream of the exhaust gas and CO
The CO ₂ separated and CO ₂ separation membrane 37 which separates the ₂ consisting supply pump 38 for supplying the catalytic reactor 2 CO ₂
It has a supply device 7.

In the gas engine 1, since the exhaust gas discharged from the CO ₂ supply device 7 to the atmosphere is a small amount of CO _{2 and} is N ₂ gas or the like, it does not become air pollution that causes environmental deterioration. The catalytic reactor 2 is constituted by reacting CH ₄ and CO ₂ by using Ni or Pt as a catalyst and thermally decomposing into CO and H ₂ . The catalytic reactor 2 is arranged in the collecting portion of the exhaust manifold 39, and the exhaust gas discharged from the main chamber 1A of the combustion chamber is about 900 ° C to about 800 ° C.
Since it is in a high temperature state of about ℃, it is sufficiently high temperature for reforming by thermal decomposition of CH ₄ . The catalytic reactor 2 is composed of a catalyst device having a heat exchange action, and accommodates an exhaust gas passage through which exhaust gas flows and a porous member coated with a Ni or Pt catalyst 33 inside a partition wall of the exhaust gas passage. It is composed of a gas fuel passage that is formed into a gas phase-gas phase heat exchanger. The catalytic reactor 2 is disposed in the exhaust passage 8 and contains, for example, an exhaust gas passage through which exhaust gas flows and a gas containing a porous member whose surface is covered with a catalyst 33 installed inside a partition wall of the exhaust gas passage. It is composed of a body fuel passage.

The hot exhaust gas from the main chamber 1A flows through the exhaust gas passage of the catalytic reactor 2 to generate Ni and Pt.
The gas body fuel passage filled with the catalyst 33 is heated. Then, the mixed gas of CH ₄ and CO ₂ flowing in the gas fuel passage heated to a high temperature of about 800 ° C. or higher comes into contact with the catalyst 33, CH ₄ is thermally decomposed into CO and H ₂ , and CO ₂ becomes CO 2.
It is thermally decomposed into CO and converted into reformed fuel of H ₂ .
Next, the reformed fuel obtained by converting the natural gas is supplied from the intake manifold 40 to the sub chamber 1B of each cylinder by the fuel pressurizing pump 13 through the reformed fuel supply passage 9.

Main chamber 1A of combustion chamber in gas engine 1
The sub-chamber 1B and the sub-chamber 1B have a heat-shielding structure composed of a ceramic member and a heat-shielding layer, so that the exhaust gas discharged from the main chamber 1A through the exhaust manifold 39 is about 900 ° C to 80 ° C.
It is a high temperature gas of 0 ° C. Therefore, in the gas engine 1,
After the heat energy of the exhaust gas is subjected to thermal decomposition in the catalytic reactor 2, the heat energy is recovered by the turbocharger 3, the first stage heat exchanger 4 and the second stage heat exchanger 6. There is.

The turbocharger 3 is, as shown in FIG. 2, a turbine 15 driven by exhaust gas, a turbine 15 connected to the turbine 15 and a turbine 1.
It is composed of a compressor 16 driven by a motor 5, and an alternator or generator 17 provided for a shaft 18. The compressor 16 is driven by the turbine 15 to pressurize air into compressed air and supply the compressed air from the intake manifold 40 to the main chamber 1A of each cylinder through the intake passage 10. The generator 17 is the turbine 1
The rotational force of 5 can be taken out as electric power and the exhaust gas energy can be recovered as electric energy.

The first-stage heat exchanger 4 includes a steam passage 35 in which a porous ceramic member through which steam heated by the second-stage heat exchanger 6 arranged in the first casing flows, and a steam passage 35. And an exhaust gas passage 28 in which a porous ceramic member through which exhaust gas flows is arranged. The second-stage heat exchanger 6 has a water / steam passage 36 for storing water, which is arranged in a second casing provided adjacent to the first casing and in which a porous ceramic member through which steam flows is arranged. , An exhaust gas passage 29 which is arranged around the water / steam passage 36 and in which a porous ceramic member through which the exhaust gas from the first stage heat exchanger 4 flows is arranged.

A fuel nozzle 24 for injecting the reformed fuel from the catalytic reactor 2 is provided in the exhaust passage 8A downstream of the turbocharger 3 and upstream of the first stage heat exchanger 4. . The reformed fuel to the fuel nozzle 24 is supplied from the catalytic reactor 2 through the auxiliary fuel supply passage 23.

As shown in FIG. 3, the steam turbine 5 is composed of a turbine 19 driven by steam generated in the first stage heat exchanger 4 and a generator 20 provided on a shaft 21. . Therefore, the steam energy drives the turbine 19, and the rotational force thereof is recovered by the generator 20 as electric power. The second stage heat exchanger 6 provided in the exhaust passage 8B is a gas-liquid phase heat exchanger and generates steam by the exhaust gas energy, and the steam is generated by the steam passage 41.
Through the first stage heat exchanger 4. The steam that has driven the steam turbine 5 becomes a fluid with the low temperature steam (moisture containing water) and is discharged to the condenser 14 through the fluid passage 27.
Is again fed to the second stage heat exchanger 6 through the water passage 26. Further, the exhaust gas that has passed through the second stage heat exchanger 6 is sent to the CO ₂ supply device 7 as a low temperature exhaust gas (for example, about 200 ° C.) in which most of the heat energy is recovered.

The CO ₂ supply unit 7 is composed of, for example, a CO ₂ supply unit 7 containing a plurality of rod-shaped CO ₂ separation membranes 37 arranged in the exhaust passage 8C through which the low-temperature exhaust gas flows. The exhaust gas sent from the exhaust passage 8C to the CO ₂ supply device 7 passes through the CO ₂ separation membrane 37
₂ is separated from the exhaust gas, N ₂ which can not pass through the CO ₂ separation membrane 37, O _2, H ₂ O or the like is discharged by bypassing the CO ₂ separation membrane 37 to the exhaust passage, the separated CO ₂ is CO ₂
It is supplied to the catalytic reactor 2 through the CO ₂ supply passage 22 by the operation of the supply pump 38. CO ₂ supply device 7 CO ₂ separation membrane 37 accommodated in the alumina, silica, a ceramic porous body is composed of an inorganic separation membrane made of a porous ceramic zeolitic a type filtration membrane, molecular can not be passed through the large N ₂ and O _2, H ₂ O in diameter (water vapor), passed through a small CO ₂ molecular diameters, CO ₂ supply passage the CO ₂ by the operation of the CO ₂ suction supply pump 38 It can be fed through 22 to the catalytic reactor 2.

In the CO ₂ supply device 7, N ₂ and H ₂ O gas (water vapor) that could not pass through the CO ₂ separation membrane 37
Is discharged to the atmosphere through the exhaust passage 8D. Exhaust passage 8D
The, for example, a pressure regulating valve 42 is provided, the pressure of the exhaust gas discharged into the atmosphere is adjusted by the pressure regulating valve 42, CO ₂ separation membrane 37 in the CO ₂ supply device 7
The amount of CO ₂ taken in by the CO ₂ suction supply pump 38 is adjusted.

The gas engine equipped with this natural gas reforming apparatus is constructed as described above and operates as follows.

With the control valve 31 closed, air from the compressor 16 of the turbocharger 3 is supplied from the intake manifold 40 to the main chamber 1A through the intake passage 10 by opening an intake valve (not shown). The air in the main chamber 1A is compressed in the compression stroke with the control valve 31 closed.
Meanwhile, the natural gas fuel is supplied from the fuel tank 11 to the catalytic reactor 2 through the natural gas supply passage 34, the natural gas is converted into the reformed fuel, and the fuel valve 32 is opened with the control valve 31 closed. The fuel pressurizing pump 13 operates, and the reforming fuel is supplied from the catalytic reactor 2 to the sub chamber 1B through the reforming fuel supply passage 9. The control valve 31 is opened near the top dead center of the compression stroke, the compressed air in the main chamber 1A flows into the sub chamber 1B, the reformed fuel is mixed with the compressed air and ignited and burned, and the piston 43 is moved to the expansion stroke. To work.

In the exhaust stroke, the exhaust gas from the main chamber 1A and the sub chamber 1B is exhausted through the exhaust passage 8. When the hot exhaust gas passes through the catalytic reactor 2, it converts natural gas into reformed fuel by its thermal energy, and then is sent to the turbocharger 3. In the turbocharger 3, the turbine 15 is driven, and the rotational force thereof is converted into electric energy by the generator 17 and also drives the compressor 16. The electric power obtained by the generator 17 is stored in a battery or consumed to drive an auxiliary machine. The compressor 16 also has a function of supplying air to the combustion chamber through the intake passage 10. The exhaust gas passes through the turbine 15 of the turbocharger 3 and is sent to the first stage heat exchanger 4 through the exhaust passage 8A.

A fuel nozzle 24 is provided in the exhaust passage 8A, and the fuel nozzle 24 injects a part of the reformed fuel fed from the catalytic reactor 2 through the auxiliary fuel supply passage 23 into the exhaust passage 8A. Since the exhaust gas flowing through the exhaust passage 8A contains a large amount of O ₂ , the reformed fuel injected from the fuel nozzle 24 is ignited and burned to increase the enthalpy of the exhaust gas. The exhaust gas sent to the first stage heat exchanger 4 passes through the exhaust gas passage 28, and then is sent to the second stage heat exchanger 6 through the exhaust gas 8B. When passing through the exhaust gas passage 28, the exhaust gas exchanges heat with the steam sent from the second stage heat exchanger 6 through the steam passage 41 to the steam passage 35 to heat to a high temperature.

The steam heated to a high temperature in the first stage heat exchanger 4 is sent to the steam turbine 5 through the high temperature steam passage 25 and drives the turbine 19. The generator 20 generates electricity by driving the turbine 19. The electric power generated by the generator 20 is stored in a battery or consumed to drive an auxiliary machine. After the high temperature steam drives the steam turbine 5,
It is converted into a fluid consisting of low-temperature steam or water, which fluid is sent to the condenser 14 through the fluid passage 27 to become water, and the water is driven by the water pump 12 to pass through the water passage 26 to the water of the second stage heat exchanger 6. -It is sent to the steam passage 36.

The exhaust gas sent from the first stage heat exchanger 4 to the second stage heat exchanger 6 is sent to the exhaust passage 8C through the exhaust gas passage 29 of the second stage heat exchanger 6. When the exhaust gas passes through the exhaust gas passage 29, the water / steam passage 3
The water passing through 6 is converted to steam by heat exchange. The exhaust gas sent to the exhaust passage 8C is used as a catalyst reactor 2, a turbocharger 3, a first stage heat exchanger 4 and a second stage heat exchanger 6.
Heat energy is recovered by, for example, 200
Since the temperature has dropped to around ℃, CO ₂ supply device 7
The CO ₂ separation membrane 37 will not be damaged even if it is sent to the air. The exhaust gas sent to the CO ₂ supply device 7 is CO
₂ By passing through the separation membrane 37, C
O ₂ is separated. The separated CO ₂ is separated from the CO ₂ supply device 7 by the operation of the CO ₂ suction supply pump 38.
_{2 It} is sent to the catalytic reactor 2 through the supply passage 22.
CO ₂ is separated by passing through the CO ₂ separation membrane 37, the exhaust gas from which CO ₂ has been separated is made N _2, H ₂ O or the like which is reducing the content of CO _2, air from the exhaust passage 8D Is released to.

[0040]

Since the gas engine equipped with the natural gas reforming apparatus according to the present invention is configured as described above,
CH ₄ , which is the main component of natural gas, is mixed with CO ₂ separated from exhaust gas, and the mixed gas is passed through a catalyst to be thermally decomposed at a high temperature of about 900 to 800 ° C. by the heat energy of exhaust gas, It converts the CH ₄ into CO and H ₂ to increase the heating value. The exhaust gas emitted from the gas engine to the atmosphere is C
Since O ₂ is excluded, it is N ₂ or H ₂ O gas,
Exhaust gas does not cause air pollution and does not deteriorate the environment. The heat energy of the exhaust gas is CH ₄
After it contributes to the thermal decomposition of the gas, it is recovered by the turbocharger, the first-stage heat exchanger, and the second-stage heat exchanger provided in the exhaust passage. That is, the gas engine drives the turbocharger by the heat energy of the exhaust gas, and the exhaust gas exhausted from the turbine of the turbocharger generates steam in the first-stage heat exchanger and the second-stage heat exchanger, The steam turbine can be driven by steam, and the steam turbine can be driven to be recovered as electric power by the generator.

[Brief description of drawings]

FIG. 1 is an explanatory view showing an embodiment of a gas engine equipped with a natural gas reforming apparatus according to the present invention.

2 is an explanatory diagram showing a turbocharger including a generator incorporated in the gas engine of FIG. 1. FIG.

FIG. 3 is an explanatory diagram showing a steam turbine incorporated in the gas engine of FIG. 1.

[Explanation of symbols]

1 Gas Engine 1A Main Chamber 1B Sub-chamber 2 Catalytic Reactor 3 Turbocharger 4 First Stage Heat Exchanger 5 Steam Turbine 6 Second Stage Heat Exchanger 7 CO ₂ Supply Device 8, 8A, 8B, 8C, 8D, 8E Exhaust Passage 11 Fuel tank 24 Fuel nozzles 28, 29 Exhaust gas passage 35 Steam passage 36 Water / steam passage 37 CO ₂ separation membrane 38 CO ₂ supply pump

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI F02B 37/00 302 F02M 27/02 E F02M 27/02 C10L 3/00 Z (58) Fields investigated (Int.Cl. ⁷ , DB name) F02M 21/02 C10L 3/00 F01K 23/10 F01N 5/02 F01N 5/04 F02B 37/00 302 F02M 27/02

Claims (8)

(57) [Claims] 1. A fuel tank containing a natural gas fuel containing CH ₄ as a main component, and CH supplied from the fuel tank.
A catalytic reactor arranged in an exhaust passage for thermally decomposing ₄ by the exhaust gas discharged from the combustion chamber and converting it into reformed fuel, a reformed fuel supply device for supplying the reformed fuel to the combustion chamber, and the catalyst A turbocharger provided in the exhaust passage downstream of the reactor, a first-stage heat exchanger provided in the exhaust passage downstream of the turbocharger, and driven by steam generated in the first-stage heat exchanger Steam turbine, a condenser for converting steam discharged from the steam turbine to water, water provided in the exhaust passage downstream of the first-stage heat exchanger and converted from water sent from the condenser to steam The second stage heat exchanger for supplying the steam to the first stage heat exchanger and the CO ₂ separation membrane provided in the exhaust passage downstream of the second stage heat exchanger are used to remove CO ₂ from the exhaust gas. Separated One the CO ₂ to CO ₂ supply device supplies to the catalyst reactor, the gas engine with a natural gas reformer comprising a. 2. The gas equipped with the natural gas reforming apparatus according to claim 1, wherein the CO ₂ separation membrane is composed of an inorganic separation membrane made of alumina, silica, or zeolite-based porous ceramics. engine. 3. The catalytic reactor uses Ni or Pt as a catalyst to react CH ₄ and CO ₂ to produce CO and H.
A gas engine equipped with a natural gas reformer according to claim 1, which comprises pyrolyzing into ₂ . 4. The catalytic reactor is composed of a catalyst device having a heat exchange action, and has a surface covered with an exhaust gas passage through which the exhaust gas flows and the catalyst installed inside a partition wall of the exhaust gas passage. A gas engine equipped with the natural gas reforming apparatus according to claim 1, wherein the gas engine comprises a gas fuel passage in which the stored porous member is housed. 5. The steam passage in which a porous ceramic member, in which the steam heated by the second-stage heat exchanger arranged in a first casing flows, is arranged in the first-stage heat exchanger, The gas engine provided with the natural gas reforming apparatus according to claim 1, comprising an exhaust gas passage arranged in the steam passage and having a porous ceramic member arranged therein, through which the exhaust gas flows. 6. The water which can store water, wherein the second-stage heat exchanger is arranged in a second casing provided adjacent to the first casing and in which a porous ceramic member through which steam flows is arranged. The steam passage and the exhaust gas passage which is arranged around the water / steam passage and in which a porous ceramic member through which the exhaust gas from the first-stage heat exchanger flows is arranged. A gas engine equipped with the described natural gas reformer. 7. The fuel nozzle according to claim 1, wherein a fuel nozzle for injecting a part of the reformed fuel from the catalytic reactor is provided in the exhaust passage on the upstream side of the first stage heat exchanger. A gas engine equipped with a natural gas reformer. 8. The gas engine equipped with the natural gas reforming apparatus according to claim 1, wherein the combustion chamber is formed into a heat shield structure by a ceramic member.