JP2003120426A - Gas engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a high conversion rate by greatly promoting separation/ extraction of hydrogen from a fuel reformer, to improve a heat efficiency of the whole gas engine, after reforming a hydrocarbon fuel in the fuel reformer, for a gas engine for supplying a reformed fuel to a combustion chamber. SOLUTION: In the fuel reformer 51, a hydrogen separating device 56 capable of separating hydrogen by a separation membrane is provided. A secondary side space of the hydrogen separating device 56 and an exhaust heat boiler 52 are connected by means of a steam introduction pipe 79. The steam introduction to the secondary side space causes hydrogen partial pressure of the secondary side space to become lower than one of a primary side space, so that speeding up of separation/extraction of hydrogen from the primary side space to the secondary side space is realized.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gas engine for reforming a hydrocarbon fuel in a fuel reformer and supplying the reformed fuel to a combustion chamber. In particular, the present invention relates to measures for improving the fuel conversion rate.

[0002]

2. Description of the Related Art Conventionally, as one form of a gas engine, a hydrocarbon-based fuel (C _m H _n ) is reformed by a fuel reformer to obtain a fuel having a large calorific value, thereby improving the thermal efficiency of the engine. It is known to improve the quality.

FIG. 4 is a diagram showing a schematic configuration of a power generation system for generating power by this type of gas engine. As shown in this figure, in the present gas engine, an output shaft a1 extending from the engine body a is connected to a generator b, and the rotational driving force of the output shaft a1 causes the generator b to generate electric power. ing.

The intake system of the gas engine is composed of an air supply system and a fuel supply system, and a mixture of air supplied from the air supply system and fuel supplied from the fuel supply system enters the combustion chamber. The engine body a is supplied and driven.

The air supply system is a supercharger (compressor) c.
And an intercooler d. That is, after the air is compressed by the supercharger c, the air is cooled by the intercooler d, so that high-density air can be supplied toward the combustion chamber. The supercharger c is directly connected to the output shaft f1 of the turbine f provided in the exhaust pipe e through which the exhaust gas flows, and receives the rotational output of the turbine f to compress the air.

On the other hand, the fuel supply system is equipped with a fuel reformer g, a waste heat boiler h, a desulfurizer i, and a tank j. In this fuel supply system, hydrocarbon fuel (C _m H _n ) and steam (H
₂ O) undergoes an endothermic reaction in the fuel reformer g to change the fuel composition, whereby a fuel having a larger calorific value than the original hydrocarbon fuel can be obtained. The heat energy required for this endothermic reaction is the exhaust pipe e.
It comes from the exhaust gas that flows through.

Specifically, first, since the hydrocarbon fuel contains a sulfur content, the sulfur content is removed by the desulfurization unit i, and the hydrocarbon fuel after the removal of the sulfur content is a fuel reforming. It is supplied to the quality device g. The catalyst of the fuel reformer g (metal (Rh, Ru, Ni, Ir, Pd, Pt, Re,
Co, Fe), alkali carbonates (K ₂ CO ₃ ), basic oxides (MgO, CaO, K ₂ O), coal and other mineral substances (F
eS ₂ ), etc.) may be poisoned by sulfur (hydrogen sulfide in digestion gas or biogas, odorant of city gas, sulfur content of petroleum-based fuel, etc.). A device i and a hydrogen cylinder k for supplying hydrogen to the hydrodesulfurization device i are required. On the other hand, in the exhaust heat boiler h, steam is generated by utilizing the heat quantity of the exhaust gas flowing through the exhaust pipe e, and this steam is supplied to the fuel reformer g. Further, the fuel reformer g is provided with a heat exchanger (not shown) for acquiring the heat energy of the exhaust gas. As a result, the following endothermic reaction takes place inside the fuel reformer g.

C _m H _n + mH ₂ O → mCO + (n / 2 + m) H ₂ (1) When the hydrocarbon fuel is methane (m = 1, n = 4), the following endothermic reaction occurs.

CH ₄ + H ₂ O → CO + 3H ₂ (2) When such a reaction is performed, the calorific value of the fuel after reforming is significantly higher than that of the original hydrocarbon fuel (for example, 25
%), Whereby a fuel capable of improving power generation efficiency (power generator output / supply fuel C _m H _n ) can be obtained.

The reformed fuel is once stored in the tank j, and after removing excess residual H ₂ O by a dehumidifier (not shown) built in the tank j, it is supplied from the air supply system. The mixed air is supplied to the combustion chamber.

[0011]

However, the temperature of the exhaust gas flowing through the exhaust pipe e is about 400 ° C. to 500 ° C., and in order to favorably perform the endothermic reaction inside the fuel reformer g. In reality, the temperature is not high enough to obtain the necessary heat energy. The curve B in FIG. 2 shows the relationship between the exhaust gas temperature and the methane conversion rate in this conventional example. As shown in this figure, when the exhaust gas temperature is about 500 ° C., the methane conversion rate is 15 with the conventional reforming method.
% Was obtained, and the calorific value of the fuel after reforming was not significantly increased. That is, in the conventional configuration, the exhaust gas temperature needs to be about 700 ° C. in order to make the methane conversion rate as high as about 80%.

In order to carry out the endothermic reaction in a high temperature environment, it is conceivable to heat the exhaust gas and the fuel reformer with a newly provided heating source, but this requires additional energy to the heating source. It becomes necessary and it is difficult to improve the thermal efficiency of the gas engine as a whole.

In view of this point, the inventor of the present invention, when reforming a hydrocarbon-based fuel in a fuel reformer, sequentially separates and extracts the produced hydrogen from the fuel reformer, thereby reforming the fuel. It has already been proposed to promote the reforming reaction in the reactor to improve the conversion rate (Japanese Patent Application No. 2000-359956).
issue). Then, the inventor of the present invention has considered a configuration for further increasing the speed of separating and extracting hydrogen from the fuel reformer.

The present invention has been made in view of the above points, and an object thereof is to separate and extract hydrogen from a fuel reformer when reforming a hydrocarbon fuel in the fuel reformer. It is intended to obtain a high conversion rate by significantly promoting the above, and to improve the thermal efficiency of the gas engine as a whole.

[0015]

Means for Solving the Problems-Outline of the Invention-To achieve the above object, the present invention, when reforming a hydrocarbon-based fuel in a fuel reformer, sequentially reforms the produced hydrogen. By separating and extracting from the reactor, the reforming reaction in the fuel reformer is promoted. Then, in order to further enhance the promotion of the reforming reaction, a pressure difference is generated between the primary side space where the reformed fuel is present before the hydrogen is separated and extracted and the secondary side space where the separated and extracted hydrogen is present. Is being generated.

-Solution Means-Specifically, it is premised on a gas engine which reforms a hydrocarbon fuel by a fuel reformer and supplies the reformed fuel to a combustion chamber. This gas engine is provided with a hydrogen separation means for separating and extracting hydrogen from the reformed fuel by means of a separation membrane, and for providing a secondary side space in which the separated and extracted hydrogen exists. Then, a hydrogen supply path for supplying the hydrogen separated and extracted by the hydrogen separating means toward the combustion chamber, a steam generating means for generating steam, and the steam generated by the steam generating means for the secondary side space of the hydrogen separating means. And a steam supply path for supplying the

According to this specific matter, hydrogen generated by the reforming reaction inside the fuel reformer is sequentially extracted from the fuel reformer by the hydrogen separation means. In other words, by reducing the hydrogen concentration inside the fuel reformer, the reforming reaction can be promoted, and reforming is performed at a high conversion rate even in a relatively low temperature environment, resulting in a large thermal efficiency. It will be possible to obtain a fuel that can be rapidly increased. In particular, in the present invention, since the steam generated by the steam generating means is supplied to the secondary side space of the hydrogen separating means, in this secondary side space,
The hydrogen partial pressure is lower than that in the primary space, the amount of hydrogen passing through the separation membrane per unit time can be increased, and the separation and extraction of hydrogen are performed at a relatively high speed. As a result, even with a small-sized hydrogen separating means, a large amount of separated and extracted hydrogen can be obtained, and a high conversion rate can be obtained.

Further, in contrast to a fuel reformer in which a hydrocarbon reforming fuel and steam are subjected to an endothermic reaction in a fuel reformer, steam generation which is means for generating steam used in this endothermic reaction is carried out. The means is used as a generation source of water vapor supplied to the secondary space. That is, it is possible to effectively utilize the means for generating steam, which is a raw material used for the endothermic reaction, to obtain steam for reducing the hydrogen partial pressure in the secondary space of the hydrogen separation means. For this reason,
The conversion rate can be improved while effectively utilizing the existing means.

Further, in the case where a hydrogen supply path for supplying the hydrogen separated and extracted by the hydrogen separation means to the combustion chamber and a hydrogen storage means for storing hydrogen in the secondary space of the hydrogen separation means are provided. As the hydrogen in the secondary space is stored by the hydrogen storage means, the pressure in the secondary space decreases. This also facilitates the hydrogen separation and extraction operation.

Further, a hydrogen pump means capable of performing an occlusion operation of occlusion of hydrogen separated and extracted by the hydrogen separation means and an evacuation operation of raising the hydrogen supply pressure by releasing the stored hydrogen toward the combustion chamber. Is provided. According to this, the hydrogen separation and extraction operation by the hydrogen separation means,
The operation of supplying the separated and extracted hydrogen to the combustion chamber can be smoothly performed, and the continuous operation of the gas engine can be favorably performed while maintaining the high conversion rate. Further, if the hydrogen pump means capable of switching between hydrogen storage and release depending on the temperature, such as a hydrogen storage alloy, is adopted, the above operations can be performed while effectively utilizing the exhaust heat of the engine. It becomes possible and no special power source is required to store and release hydrogen.

In addition, hydrogen separated and extracted by the hydrogen separation means can be temporarily stored, and the amount of hydrogen mixed in the reformed fuel supplied to the combustion chamber can be adjusted. Is provided. According to this, excess hydrogen can be stored in the hydrogen storage means when the load is cut off, and the engine can be operated using the stored hydrogen when the load is applied. Therefore, it is possible to provide a gas engine with good responsiveness.

[0022]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. In this embodiment, methane gas (C
A case where the present invention is applied to a gas engine in which H ₄ ) is reformed by a fuel reformer to obtain a fuel having a large calorific value will be described. In addition, the gas engine according to the present embodiment uses its output for power generation.

(First Embodiment) First, the first embodiment will be described.

-Description of Configuration of Gas Engine- FIG. 1 is a diagram showing a schematic configuration of a power generation system for generating power by the gas engine 1 according to the present embodiment. As shown in this figure, in the gas engine 1, an output shaft 21 extending from the engine body 2 is connected to a generator 3, and the rotational driving force of the output shaft 21 causes the generator 3 to generate electric power. Has become.

The intake system of the gas engine 1 comprises an air supply system 4 and a fuel supply system 5, and the air supply system 4
A mixture of air supplied from the engine and fuel supplied from the fuel supply system 5 is supplied to a combustion chamber (not shown) of the engine body 2 to drive the engine body 2. Hereinafter, the air supply system 4 and the fuel supply system 5 will be described.

The air supply system 4 is a supercharger (compressor).
41 and an intercooler 42. That is, after the air is compressed by the supercharger 41, the air is cooled by the intercooler 42 so that high-density air can be supplied toward the combustion chamber. The supercharger 41 is directly connected to an output shaft 62 of a turbine 61 provided in the exhaust pipe 6 through which exhaust gas flows, and
It receives the rotation output of 1 and compresses air.

On the other hand, the fuel supply system 5 includes a fuel reformer 51,
An exhaust heat boiler 52 as a steam generator, a high-order desulfurization device 53, a tank 55 and the like are provided. This fuel supply system 5
Then, the fuel composition is changed by causing an endothermic reaction between methane gas (CH ₄ ) which is a hydrocarbon fuel and steam (H ₂ O) in the fuel reformer 51, whereby the calorific value of the methane gas is higher than that of the original methane gas. Is trying to get big fuel. The heat energy required for this endothermic reaction is obtained from the exhaust gas flowing through the exhaust pipe 6. Hereinafter, each element constituting the fuel supply system 5 will be described.

Water is supplied from the outside to the exhaust heat boiler 52, and the water is stored inside.
By exchanging heat with the exhaust gas flowing through the water, water is evaporated and steam is generated. The exhaust heat boiler 52 and the fuel reformer 51 are connected by a steam supply pipe 71, and the steam generated in the exhaust heat boiler 52 can be supplied into the fuel reformer 51. Further, the steam supply pipe 71 is provided with an electric valve 71a whose opening can be adjusted.

The high-order desulfurization device 53 is for removing the sulfur content contained in the methane gas. That is,
Catalyst of the fuel reformer 51 (metal (Rh, Ru, Ni, I
r, Pd, Pt, Re, Co, Fe), alkali carbonate (K ₂ CO ₃ ), basic oxide (MgO, CaO, K)
₂ O), minerals such as coal (FeS ₂ ) and the like may be poisoned by sulfur, and in order to avoid this, the high-order desulfurization device 53 is installed. In addition, this high-order desulfurization device 5
3, a pre-reforming fuel supply pipe 72 for supplying methane gas and a desulfurized fuel supply pipe 73 for supplying desulfurized fuel to the fuel reformer 51 are connected.

The high-order desulfurization unit 53 is capable of reducing the sulfur content (generally called slip sulfur) contained in the hydrocarbon fuel to the level of 1 ppb.
High-performance desulfurization operation can be performed even in an environment at room temperature. The principle of the desulfurization is such that the active metal on the metal oxide can also decompose organic sulfur such as thiophene to perform desulfurization.

Further, a desulfurized fuel supply pipe 73 for supplying the fuel from the high-order desulfurization device 53 to the fuel reformer 51 is also provided with an electric valve 73a, and during normal operation,
The electric valve 71a of the steam supply pipe 71 and the desulfurized fuel supply pipe 7
The motor-operated valve 73a of No. 3 is opened, methane gas and steam are supplied to the fuel reformer 51, and the operation of the gas engine 1 accompanying the endothermic reaction is performed. On the other hand, when the catalyst of the fuel reformer 51 is poisoned or when the power generation load is small, the electric valve 71a of the steam supply pipe 71 is opened and the electric valve 73a of the desulfurized fuel supply pipe 73 is closed. As a result, only steam is supplied to the fuel reformer 51. By supplying only this steam, the fuel reformer 51
The sulfur content that causes poisoning of the catalyst is decomposed, and thus the catalyst can be regenerated.

A hydrodesulfurization device may be provided upstream of the higher-order desulfurization device 53. According to this, the amount of sulfur introduced into the high-order desulfurization device 53 can be extremely reduced, the efficiency of sulfur removal operation in the high-order desulfurization device 53 can be improved, and the life of the high-order desulfurization device 53 can be extended. Can be achieved.

The fuel reformer 51 has a function of endothermic reaction between steam and methane gas to perform a fuel reforming operation. That is, an endothermic reaction is performed between the steam supplied from the steam supply pipe 71 and the methane gas supplied from the desulfurized fuel supply pipe 73. Further, inside the fuel reformer 51, a heat exchanger (not shown) for obtaining the heat energy of the exhaust gas is provided. As a result, the following endothermic reaction is performed inside the fuel reformer 51 under an environment of a predetermined temperature (exhaust gas temperature of about 600 ° C., for example).

CH ₄ + H ₂ O → CO + 3H ₂
(2) By carrying out such a reaction, the calorific value of the fuel after reforming is significantly higher than that of the original methane gas, and thereby the power generation efficiency (power generator output / fuel supply) can be improved. To be able to get.

The fuel reformer 51 and the tank 55 are for supplying the hydrogen gas and other fuels (CO, CH ₄ , H ₂ O) obtained by the endothermic reaction to the tank 55. Are connected by a fuel supply pipe 76. The fuel supply pipe 76 has an electric valve 76 with an adjustable opening.
a is provided.

The tank 55 to which the fuel is supplied by the fuel supply pipe 76 temporarily stores the fuel, mixes the reformed fuel with air through the reformed fuel supply pipe 78, and supplies the mixed fuel to the combustion chamber. It is supposed to do.

The fuel reformer 51 is provided with a hydrogen separator 56 as a hydrogen separator. The hydrogen separator 56 separates and extracts hydrogen gas generated by the endothermic reaction in the fuel reformer 51 from other gases and steam. As a specific configuration of the hydrogen separation device 56, a separation membrane is arranged in the internal space thereof, and the separation membrane separates the upstream side primary side space and the downstream side secondary side space. The primary side space is the fuel reformer 51.
In the space on the side, hydrogen gas and other gases generated by the endothermic reaction are present. A hydrogen recovery pipe 75, which will be described later, is connected to the secondary space, and the hydrogen gas separated and extracted by the separation membrane is led to the hydrogen recovery pipe 75.

As the separation membrane, palladium alloy, palladium-based alloy, inorganic separation membrane, porous glass membrane, porous hollow glass fiber membrane, porous ceramic membrane, zeolite membrane, cellulose acetate membrane, polyimide, polyamide, polysulfone porous Membrane / silicone. For example, the inorganic separation membrane is formed as a membrane having pores through which only hydrogen molecules can pass. In particular, inorganic separation membranes, porous glass membranes, porous hollow glass fiber membranes, and porous ceramics membranes are preferable because they have excellent heat resistance and high mechanical strength. Further, as the porous ceramic material, specifically,
Examples include zirconia, zeolite, silica and alumina.

In addition to the above structure, the hydrogen separator 56
A hydrogen storage substance may be housed in the secondary side space of the above to accelerate the separation and extraction of hydrogen gas. Examples of this hydrogen storage material include hydrogen storage alloys. In addition, carbon nanofibers, fullerenes, multi-layer fullerenes, substances composed of carbon molecules such as carbon nanotubes, metal hydrides, salt hydrides, metal bond hydrides, boundary region hydrides, covalent bond hydrides, organic carbonization It is also possible to adopt hydrogen, metal hydride, or chemical hydride as the hydrogen storage substance.

The separation membrane and the hydrogen storage material are not limited to these, and various materials can be used as long as they can separate and extract hydrogen. With this configuration, the hydrogen generated by the endothermic reaction in the fuel reformer 51 is sequentially separated and extracted by the hydrogen separator 56, so that the endothermic reaction in the fuel reformer 51 can be promoted. .

The hydrogen separator 56 and the fuel supply pipe 76 are connected by a hydrogen recovery pipe 75 which constitutes a hydrogen supply passage. That is, the hydrogen gas separated and extracted by the hydrogen separation device 56 is introduced into the fuel supply pipe 76 through the hydrogen recovery pipe 75, and is mixed with the hydrogen gas and other fuels flowing through the fuel supply pipe 76. There is.

The feature of this embodiment is that the exhaust heat boiler 52 and the hydrogen separator 56 are connected by a steam introducing pipe 79 which constitutes a steam supply path.
That is, part of the steam generated in the exhaust heat boiler 52 can be supplied to the secondary side space of the hydrogen separation device 56, and the supply of this steam reduces the hydrogen partial pressure in the secondary side space to the primary side. It can be set lower than the space. Further, the steam introducing pipe 79 is provided with an electric valve 79a whose opening can be adjusted.

Further, the fuel supply system 5 of the present gas engine 1 has a heat exchanger 57 and a deionized water device 58 in addition to the above structure.
Is provided.

The heat exchanger 57 includes the reformed fuel (reformed gas) flowing through the fuel supply pipe 76, and the methane gas supplied to the fuel reformer 51 (the methane gas desulfurized by the high-order desulfurization device 53). ) Is to exchange heat with.
As a result, the methane gas supplied to the fuel reformer 51 can be preheated. In addition, this heat exchanger 57
Is the reformed fuel (reformed gas) flowing through the fuel supply pipe 76.
And heat exchange is performed between the pure water supplied from the pure water device 58 to the exhaust heat boiler 52. Thereby, the pure water supplied to the exhaust heat boiler 52 can be preheated. As described above, by adopting the configuration in which the methane gas and the pure water which are the raw materials of the gas engine 1 are preheated by the reformed fuel, the thermal energy in the reformed fuel can be recovered and the exhaust heat recovery amount can be increased. Can be achieved.

The pure water device 58 is a water supply pipe 58a.
Is connected to the exhaust heat boiler 52 by the heat exchanger 5
7 is connected to this water supply pipe 58a by a water return pipe 57a. That is, the water formed by condensing the water contained in the reformed fuel by the heat exchanger 57 is used as the waste heat boiler 52.
It can be used as a raw material for the steam generated in. Therefore, the water contained in the reformed fuel can be effectively used without being discarded, and the running cost of the pure water supply facility can be reduced.

On the other hand, the pure water device 58 is supplied with, for example, tap water, generates pure water from the tap water, and supplies the pure water to the exhaust heat boiler 52 through the water supply pipe 58a. That is, high purity pure water is generated by removing impurities such as halogen and arsenic contained in tap water. Specific examples of the pure water device 58 include a distillation pure water device, a cartridge pure water device, an ion exchange pure water device, an electric regeneration pure water device, and a continuous ion exchange method applying the electrodialysis principle ( Devices such as EDI) are listed.

In particular, as a method for removing halogen, an activated carbon filtration method, a microfiltration method (using an MF membrane (microfilter) or the like), an ultrafiltration method (using a UF membrane (ultrafilter) or the like), reverse osmosis At least one of the membrane methods (by RO membrane (reverse osmosis) etc.) is selected. On the other hand, as a method for removing arsenic, coagulation sedimentation method (precipitation method), ion exchange method, activated alumina method, low pressure reverse osmosis membrane method, reverse osmosis membrane method (pressure is applied in the direction opposite to the osmotic pressure) Method) and at least one of the ADI methods is selected.

For example, in the above sedimentation method, raw water (tap water)
An oxidant and a coagulant are injected into the mixture, which are mixed by a mixer and passed through a UD filter. At this time, when raw water passes through the filter layer of the filter, agglomerated flocs incorporating arsenic are supplemented. This treated water is filtered more rapidly to remove residual arsenic and suspended matter.

In the activated alumina method, the oxidizing agent and the raw water into which the acid for pH adjustment has been injected are mixed in a mixer, and the mixture is allowed to flow into the activated alumina adsorption tower. Then, this treated water is readjusted in the purification pond to raise the pH value to near neutral. Furthermore, suspended matter, iron, manganese, etc. are removed by a filter.

Here, pure water generally means water containing impurities at a concentration of the order of ppm (mg / l). Moreover, the high-performance pure water device 58 can also generate ultrapure water. The ultrapure water generally means water containing impurities at a concentration on the order of ppb (μg / l).

By thus converting the water supplied to the exhaust heat boiler 52 to pure water, it is possible to prevent the water vapor supplied to the fuel reformer 51 from containing impurities such as halogen and arsenic. In this way, the endothermic reaction can be efficiently performed. As a result, the life of the fuel reformer 51 and the exhaust heat boiler 52 can be extended, and the cost can be reduced by eliminating the need for a pure water tank.

The gas engine 1 is also provided with a controller 8 for controlling each part. The controller 8 is connected to a plurality of sensors 81, 82, 83, receives detection signals from the sensors 81, 82, 83, and also each of the motor-operated valves 71a, 73a, 76.
The degree of opening of a and 79a is controlled. As the sensor, a load sensor 8 for detecting the load of the generator 3 is used.
1, a knock sensor 82 for measuring the knocking strength of the engine body 2, the tank 55 to the engine body 2
Concentration sensor 83 for measuring the hydrogen component concentration in the fuel supplied to the fuel cell (hydrogen component concentration in the reformed fuel supply pipe 78)
Is raised. The above is the configuration description of the gas engine 1.

-Description of Operation of Gas Engine 1- Next, the operation of the gas engine 1 configured as described above will be described.

First, with the electric valve 71a of the steam supply pipe 71 opened, the water supplied from the pure water device 58 to the exhaust heat boiler 52 is exhausted by the exhaust pipe 6 in the exhaust heat boiler 52.
It is heated by the exhaust gas flowing through and becomes steam. Then, a part of this steam is sequentially supplied to the fuel reformer 51 through the steam supply pipe 71. Further, other steam is introduced into the secondary space of the hydrogen separator 56 by the steam introducing pipe 79.

At the same time, methane gas is supplied to the high-order desulfurization device 53 through the pre-reforming fuel supply pipe 72, and the desulfurization operation is performed here. In the desulfurization operation in the high-order desulfurization device 53, as described above, slip sulfur can be reduced to the level of 1 ppb in a room temperature environment. Therefore, almost no sulfur is present in the methane gas supplied from the higher-order desulfurization device 53 to the fuel reformer 51 by the desulfurization fuel supply pipe 73, and the catalyst of the fuel reformer 51 is almost not poisoned. Disappear.

In this way, the above endothermic reaction is carried out with the steam and methane gas supplied to the fuel reformer 51. In addition to steam and methane gas, the fuel reformer 51 also includes air, oxygen (O ₂ ), carbon dioxide (C
O ₂ ) is also supplied. During the endothermic reaction,
The heat energy of the exhaust gas is acquired by the heat exchanger in the fuel reformer 51, whereby an endothermic reaction is performed inside the fuel reformer 51 under an environment of a predetermined temperature, and carbon monoxide (CO) is generated. And hydrogen gas (H ₂ ) are generated. At this time, unreformed steam (H ₂ O) and methane gas (CH ₄ ) are also present inside the fuel reformer 51.

The hydrogen gas in the fuel reformer 51 is separated and extracted from other gases and water vapor by the hydrogen separation device 56, and the hydrogen gas in the engine body 2 is passed through the hydrogen recovery pipe 75 and the fuel supply pipe 76. Supplied to the room. By separating and extracting the hydrogen gas in the fuel reformer 51, the endothermic reaction is promoted in the fuel reformer 51, and the fuel is reformed at a high conversion rate.

At this time, as described above, the exhaust heat boiler 5
A part of the steam generated in 2 is supplied to the secondary space of the hydrogen separator 56 by the steam introduction pipe 79. Therefore, in this secondary space, the partial pressure of hydrogen is lower than in the primary space, and the separation and extraction of hydrogen from the primary space to the secondary space are performed at a relatively high speed. . As a result, the amount of separated and extracted hydrogen per unit time increases, the endothermic reaction is greatly promoted, and the fuel is reformed at a high conversion rate.

When supplying fuel to the engine body 2,
The electric valve 76a of the fuel supply pipe 76 is opened.
The hydrogen gas separated and extracted is mixed into the hydrogen gas, methane gas, carbon monoxide, and water vapor in the fuel reformer 51 through the hydrogen recovery pipe 75, and these fuels and the like are stored in the tank 55 through the fuel supply pipe 76. Supplied. Then, the reformed fuel is mixed with the air supplied from the air supply system 4 from the tank 55 through the reformed fuel supply pipe 78 and is supplied to the combustion chamber of the engine body 2.

As a result, the engine body 2 is driven, and the generator 3 is driven by the rotational driving of the output shaft 21 to generate electricity.

-Effects of Embodiment-As described above, in the present embodiment, when the methane gas is reformed by the fuel reformer 51, the generated hydrogen is sequentially separated from the fuel reformer 51 by the hydrogen separator 56. By extracting, the hydrogen concentration in the fuel reformer 51 is reduced to promote the endothermic reaction. Also,
By supplying a part of the steam generated in the exhaust heat boiler 52 to the secondary space of the hydrogen separation device 56, the partial pressure of hydrogen in the secondary space is lowered, and the separation and extraction operation of hydrogen is accelerated. . Therefore, in a relatively low temperature environment (for example, 60
Even if the temperature is about 0 ° C.), the reforming is performed at a high conversion rate, a fuel capable of significantly increasing the power generation efficiency is obtained, and the power generation efficiency of the gas engine as a whole can be improved. it can. As a result, in the gas engine 1 of this embodiment,
The amount of fuel required to obtain the same amount of power generation as the conventional one can be reduced, and energy saving can be improved.

FIG. 2 shows the relationship between the exhaust gas temperature and the methane conversion rate. The curve A relates to the gas engine 1 of this embodiment, and the curve B corresponds to the conventional gas engine as described above (see FIG. 4). ). As shown in this figure, when the exhaust gas temperature is 600 ° C., the methane conversion rate of the conventional type is only about 40%, whereas the high conversion rate of 90% or more is obtained in the present embodiment. It has been possible to significantly improve

(Second Embodiment) Next, a second embodiment will be described. The present embodiment is a modification of the configuration for promoting the hydrogen separation / extraction operation in the hydrogen separation device 56. Other configurations are similar to those of the above-described first embodiment. Therefore, only the differences from the first embodiment will be described here.

As shown in FIG. 3, in the hydrogen separation device 56 of the gas engine 1 according to this embodiment, the secondary side space has a tank 55 through a hydrogen pump unit 9 as hydrogen pump means.
It is connected to the. The hydrogen pump unit 9 will be described below.

One of the hydrogen pump units 9 is connected to the secondary space of the hydrogen separator 56 by a hydrogen recovery pipe 75, and the other is connected to the tank 5 by a hydrogen release pipe 91.
Connected to 5. Further, the hydrogen release pipe 91 is provided with an electric valve 91a whose opening can be adjusted.

The hydrogen pump unit 9 includes first and second hydrogen pumps 92, (93) which are formed by connecting a pair of hydrogen storage bodies 92a, 92b, (93a, 93b) in series.
It is provided with a hydrogen storage body 94 as a hydrogen storage means connected to the hydrogen pumps 92 and (93). Each of the hydrogen storage bodies 92a to 93b and the hydrogen storage body 94 contains the above-mentioned hydrogen storage material. Further, the hydrogen storage bodies 92a to 93b and the hydrogen storage body 94 are provided with a hot / cold heat source (not shown). When cooled by the hot / cold heat source, the hydrogen storage operation is performed while the hydrogen storage operation is performed. Is designed to perform a hydrogen releasing operation. It is also possible to use the exhaust heat of the engine body 2 as this heating source. As the configuration of the hydrogen storage body 94, specifically, a hydrogen storage alloy tank, a compressed hydrogen tank, a liquid hydrogen tank, a metal hydride tank, a chemical hydride tank, or the like can be adopted.

In the hydrogen pump unit 9 thus constructed, in each of the hydrogen pumps 92 and 93, the upstream hydrogen storage bodies 92a and (93a) are cooled and the downstream hydrogen storage bodies 92b and (93b) are cooled. When heated, hydrogen is taken out from the secondary space of the hydrogen separator 56 and stored in the upstream hydrogen storage bodies 92a, (93a), and at the same time, the downstream hydrogen storage bodies 92b, (93b) are stored. In (), the hydrogen that has been stored in advance is released toward the tank 55 (hereinafter, hydrogen storage operation). On the contrary, when the upstream side hydrogen storage bodies 92a, (93a) are heated and the downstream side hydrogen storage bodies 92b, (93b) are cooled, the upstream side hydrogen storage bodies 92a, (93a) store the hydrogen storage bodies 92a, (93a). The stored hydrogen is supplied to the hydrogen storage bodies 92b, (93b) on the downstream side and stored in the hydrogen storage bodies 92b, (93b) on the downstream side (hereinafter, hydrogen storage preliminary operation). Then, in each of the hydrogen pumps 92 and 93, a state in which one performs a hydrogen storage / release operation and the other performs a hydrogen storage preliminary operation is alternately repeated at predetermined time intervals. As a result, the hydrogen separator 5
Hydrogen taken out from the secondary side space of No. 6 is continuously stored in the tank 5
It is possible to discharge toward 5.

When the load is cut off (when the fuel supply to the engine body 2 is not necessary), the hydrogen storage body 94 is cooled and the hydrogen in the secondary space of the hydrogen separation device 56 is taken out and temporarily. Store. When the load is applied, the hydrogen storage body 94 is heated and the stored hydrogen is stored in the tank 55.
To be released to. As a result, an appropriate amount of hydrogen gas can be supplied as fuel according to the operating state of the engine body 2, and the responsiveness of the gas engine 1 can be excellently obtained.

As the operation of adjusting the amount of hydrogen gas released to the tank 55, control of heating and cooling of the hydrogen storage bodies 92a to 93b and the hydrogen storage body 94 described above and the motor-operated valve 91 are performed.
It is performed by controlling the opening degree of a.

According to the present embodiment, the hydrogen pump unit 9 can simultaneously and continuously take out hydrogen from the secondary space of the hydrogen separator 56 and release hydrogen toward the tank 55. Therefore, the practicality of the gas engine 1 can be improved. Further, as a driving principle of the hydrogen pump unit 9, a configuration is adopted in which storage and release of hydrogen are switched depending on temperature, so that exhaust heat of the engine can be effectively used and storage and release of hydrogen can be performed. It is also possible to eliminate the special power source for carrying out.

-Other Embodiments- In the above embodiment, the present invention is applied to the gas engine 1 in which methane gas as a hydrocarbon-based fuel is reformed by the fuel reformer 51 to obtain a fuel having a large calorific value. I explained about the case. The present invention is not limited to this, and as the hydrocarbon fuel, it is also possible to apply fuels such as natural gas, petroleum liquid fuel, digestive gas, biogas, alcohol fuel and the like.

The gas engine is not limited to the one for power generation, but the present invention can be applied to gas engines used for various purposes.

Further, in order to further promote the endothermic reaction in the fuel reformer 51, separated hydrogen and reformed fuel (fuel after reforming and other than hydrogen) are formed inside the fuel reformer 51. ) Or a part of hydrocarbon fuel (fuel before reforming) is burned to raise the internal temperature of the fuel reformer 51. With this configuration,
In combination with the effect of promoting the endothermic reaction by extracting hydrogen from the fuel reformer 51, an extremely high conversion rate can be realized. For example, when the internal temperature of the fuel reformer 51 is raised to 800 ° C. by the combustion of the separated hydrogen, the reformed fuel or the hydrocarbon fuel, as shown in FIG.
A conversion rate of approximately 100% can be obtained.

Further, in each of the above-described embodiments, the description has been made of the case where the steam and the hydrocarbon-based fuel are endothermic-reacted to perform the fuel reforming. However, in the present invention, the carbon dioxide and the hydrocarbon-based fuel are endothermic-reacted. It is also possible to apply it to fuel reforming.

[0075]

As described above, according to the present invention, when reforming hydrocarbon-based fuel in the fuel reformer, the produced hydrogen is sequentially separated and extracted from the fuel reformer, so that The reforming reaction is promoted. Further, since the steam generated by the steam generating means is supplied to the secondary side space of the hydrogen separating means, the hydrogen partial pressure in this secondary side space is lower than that in the primary side space, and the primary side space It is possible to perform the separation and extraction of hydrogen from the to the secondary space at a relatively high speed. As a result, the amount of separated and extracted hydrogen per unit time is increased even with a small-sized hydrogen separating means, a high conversion rate can be obtained, and the thermal efficiency of the gas engine as a whole can be improved.

In the case where a hydrogen supply path for supplying the hydrogen separated and extracted by the hydrogen separation means to the combustion chamber and a hydrogen storage means for storing hydrogen in the secondary space of the hydrogen separation means are provided. As the hydrogen in the secondary space is occluded by the hydrogen occluding means, the pressure in the secondary space decreases, which also facilitates the hydrogen separation / extraction operation. The power generation efficiency of the engine as a whole can be improved.

Further, a hydrogen pump means capable of performing an occlusion operation of occlusion of hydrogen separated and extracted by the hydrogen separation means and an evacuation operation of increasing the hydrogen supply pressure by releasing the stored hydrogen toward the combustion chamber. When the above is provided, the continuous operation of the gas engine can be favorably performed while maintaining a high conversion rate.

[Brief description of drawings]

FIG. 1 is a diagram showing a schematic configuration of a power generation system that generates power by a gas engine according to a first embodiment.

FIG. 2 is a diagram showing a relationship between exhaust gas temperature and methane conversion rate.

FIG. 3 is a diagram showing a schematic configuration of a power generation system that generates power by a gas engine according to a second embodiment.

FIG. 4 is a view corresponding to FIG. 1 in a conventional example.

[Explanation of symbols]

1 gas engine 51 Fuel reformer 52 Exhaust heat boiler (steam generation means) 56 Hydrogen separation device (hydrogen separation means) 75 Hydrogen recovery pipe (hydrogen supply route) 79 Steam introduction pipe (steam supply path) 9 Hydrogen pump unit (hydrogen pump means) 94 Hydrogen storage (hydrogen storage means)

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) F02M 33/00 F02M 33/00 Z F term (reference) 4D006 GA41 JA02C JA30A JA65A KA01 KA72 KB12 KB30 KE22 MA01 MB03 MC02 MC03 MC04 PA01 PB18 PB66 4G040 AA01 AA12 EA03 EA06 EB01 EB03 EB33 EB42 EB43 FA02 FB01 FC01 FE01

Claims (6)

[Claims] 1. A gas engine for reforming a hydrocarbon-based fuel in a fuel reformer and supplying the reformed fuel to a combustion chamber, wherein a separation membrane separates and extracts hydrogen from the reformed fuel. At the same time, the hydrogen separating means having the secondary space in which the separated and extracted hydrogen exists, the hydrogen supply path for supplying the hydrogen separated and extracted by the hydrogen separating means toward the combustion chamber, and the steam generation A gas engine, comprising: a steam generating means for generating the steam; and a steam supply path for supplying the steam generated by the steam generating means to the secondary side space of the hydrogen separating means. 2. The gas engine according to claim 1, wherein the fuel reformer is adapted to perform fuel reforming by causing an endothermic reaction between hydrocarbon fuel and steam, and the steam generating means is A gas engine for generating steam used for this endothermic reaction. 3. A gas engine for reforming a hydrocarbon fuel in a fuel reformer and supplying the reformed fuel to a combustion chamber, wherein hydrogen is separated and extracted from the reformed fuel by a separation membrane. In addition, the hydrogen separation means having the secondary space in which the separated and extracted hydrogen exists, the hydrogen supply path for supplying the hydrogen separated and extracted by the hydrogen separation means toward the combustion chamber, and the hydrogen separation A gas engine, comprising: hydrogen storage means for storing hydrogen in the secondary side space of the means. 4. A hydrogen separation device for separating and extracting hydrogen from the reformed fuel in a gas engine for reforming hydrocarbon-based fuel in a fuel reformer and supplying the reformed fuel to a combustion chamber. Means, a hydrogen pump means capable of performing an occlusion operation of occlusion of hydrogen separated and extracted by the hydrogen separation means, and an evacuation operation of increasing the hydrogen supply pressure by releasing the stored hydrogen toward the combustion chamber. A gas engine characterized by being provided. 5. A hydrogen separation device for separating and extracting hydrogen from the reformed fuel in a gas engine for reforming hydrocarbon-based fuel in a fuel reformer and supplying the reformed fuel to a combustion chamber. And a hydrogen storage means capable of temporarily storing the hydrogen separated and extracted by the hydrogen separation means and adjusting the mixing amount of the stored hydrogen with respect to the reformed fuel supplied toward the combustion chamber. A gas engine characterized by being used. 6. A gas engine, which is configured by combining a plurality of configurations according to any one of claims 1 to 5.