WO2011152366A1

WO2011152366A1 - Energy-generating system

Info

Publication number: WO2011152366A1
Application number: PCT/JP2011/062422
Authority: WO
Inventors: 雅史能島; 石川　敬郎; 島田　敦史
Original assignee: 株式会社日立製作所
Priority date: 2010-05-31
Filing date: 2011-05-30
Publication date: 2011-12-08
Also published as: JP2011247235A; JP5575549B2

Abstract

Disclosed is a small-scale energy-generating system that generates electric power and hydrogen. The disclosed hydrogen station (1), which generates electric power and hydrogen, is provided with: a generator (13) and an engine (11) that generate power and high-temperature exhaust gas along with the operation thereof; a reaction vessel (30) that causes a dehydrogenation reaction of MCH using the heat of high-temperature exhaust gas from the engine (11), thus generating hydrogen; and an electrolysis device (60) that electrolyzes water using the power from the generator (13), producing hydrogen and oxygen.

Description

Energy generation system

The present invention relates to an energy generation system that generates electric power and hydrogen.

In recent years, depletion of resources and destruction of the environment are regarded as major problems on the earth, and there is a demand for the construction of a zero-emission society using renewable energy. For example, it is recommended to use natural energy such as wind power and sunlight, or unused energy that exists in nature but has not been used yet.

In addition, it is expected to be an alternative energy for fossil fuels, focusing on hydrogen, which is an infinitely existing and storable energy in nature. In particular, the development of hydrogen vehicles using hydrogen, fuel cells as distributed power sources, fuel cell vehicles, etc. is underway, and in parallel, hydrogen stations (hydrogen supply infrastructure) that supply hydrogen to hydrogen vehicles, etc. Development and maintenance are also underway.

Among these, for the hydrogen station, (1) hydrogen (gas) is compressed, stored and supplied, and (2) hydrogen is physically adsorbed or chemically (atomic) occluded, stored and supplied. (3) Cooling hydrogen (gas), storing and supplying hydrogen (liquid), (4) Producing hydrogen by reforming raw fuel such as natural gas and methanol, A storage and supply system has been proposed.

For example, Patent Document 1 proposes a “high-pressure hydrogen supply system” that generates hydrogen by dehydrogenating an organic hydride (hydrogen storage medium) that stores hydrogen under a catalyst activated by the heat of exhaust gas. Has been.

JP 2004-197705 A

However, in the “high pressure hydrogen supply system” of Patent Document 1, when a large amount of hydrogen is produced, a large amount of exhaust gas must be supplied to a hydrogen production apparatus that produces hydrogen, and exhaust gas and electric power are generated. As a result, the size of the engine (generator) increases, and the scale of the entire system increases.

Therefore, an object of the present invention is to provide a small-scale energy generation system that generates electric power and hydrogen.

As means for solving the above-mentioned problems, the present invention provides an energy generation system that generates electric power and hydrogen, and generates electric power and high-temperature exhaust gas when operated, and high-temperature from the electric power generation means. The hydrogen generating means for generating hydrogen by dehydrogenating the hydrogen storage medium using the heat of the exhaust gas of the gas, and the electrolysis for generating hydrogen and oxygen by electrolyzing water with the electric power from the power generating means Means for generating an energy.

According to such an energy generation system, the power generation means generates electric power and high-temperature exhaust gas as it operates. The hydrogen generation means generates hydrogen by dehydrogenating a hydrogen storage medium that chemically stores hydrogen using the heat of the high-temperature exhaust gas from the power generation means. The electrolysis means electrolyzes water with the electric power from the power generation means to generate hydrogen and oxygen.
That is, according to such an energy generation system, since hydrogen can be generated by the hydrogen generation means and the electrolysis means, a large amount of hydrogen can be produced even if the system is configured in a small scale.

According to the present invention, a small-scale energy generation system that generates electric power and hydrogen can be provided. Further aspects and advantages of the present invention, as well as other effects and further features, will become more apparent from the detailed description of exemplary and non-limiting embodiments of the present invention described below with reference to the accompanying drawings. It will be.

It is a figure which shows the structure of the hydrogen station which concerns on this embodiment. (A) is a cross-sectional view of a reactor according to this embodiment, (b) is a cross-sectional view of a reaction cell according to this embodiment, and (c) is a cross-sectional view of a reaction sheet according to this embodiment. It is.

Hereinafter, an embodiment of the present invention will be described with reference to FIGS.

≪Energy generation system configuration≫
As shown in FIG. 1, the energy generation system (hydrogen station 1) according to the present embodiment is a system that generates electric power and hydrogen (energy).
The hydrogen station 1 in the present embodiment is connected to a pipeline, a hydrogen storage tank, and the like, and can be transported to a consumption place, in addition to the purpose of supplying hydrogen as a fuel to a hydrogen automobile.
The hydrogen station 1 generates MCH (methylcyclohexane, C ₇ H ₁₄ , hydrogen storage medium) using at least the engine 11, a generator 13 that is operated by the power of the engine 11, and the heat of exhaust gas from the engine 11. Electric power that distributes the electric power generated by the reactor 30 (hydrogen generating means) that generates hydrogen and toluene (high-octane fuel, dehydrogenated material) by the dehydrogenation reaction (see formula (1)) and the generator 13 A distribution device 51 (power distribution means), an electrolysis device 60 (electrolysis means) that electrolyzes water using the distributed power to generate hydrogen and oxygen, and a controller 70 (control means) that electronically controls the system It is equipped with.
Moreover, it becomes possible to provide the compressor 14 which act | operates with the motive power of the engine 11, and the supercharger 21 (turbo apparatus). In addition, a compressor, a hydrogen storage tank, and a filling machine can be arranged on a pipe connecting the compressor 14 and the hydrogen automobile.
That is, in the present embodiment, the “power generation means that generates electric power and high-temperature exhaust gas in accordance with the operation” includes the engine 11 and the generator 13.

C ₇ H ₁₄ (MCH) → C ₇ H ₁₄ (toluene) + 3H ₂ −205 kj (1)

Note that, since the equation (1) is an endothermic reaction, the energy efficiency of the entire system is enhanced by utilizing the heat of the exhaust gas in the reactor 30, that is, by recovering the energy of the exhaust gas.

<MCH, toluene>
That is, in this embodiment, although the structure which uses MCH (methylcyclohexane) is illustrated as a hydrogen storage medium (organic hydride), for example, cyclohexane, decalin, etc. can also be used. The hydrogen storage medium is a fuel that easily adds and generates hydrogen, and is, for example, a hydrocarbon fuel or a mixed fuel thereof.

Further, in the present embodiment, a configuration using toluene as a combustion fuel is exemplified, but other examples include toluene, gasoline, heavy oil, light oil, kerosene, biofuel, alcohol, methane, LPG (Liquefied Petroleum Gas). It is also possible to use at least one selected.

Since the octane number of toluene (about 120) is higher than that of gasoline, which is a normal fuel for spark ignition, knocking is unlikely to occur in the engine 11, and the engine 11 is operated at a high compression ratio and combustion efficiency is increased. It is also possible to increase. Specifically, in the case of a general spark ignition type engine 11, a compression ratio of about 13 is the maximum value, but by using toluene, the compression ratio can be increased to 13 or more (for example, a compression ratio of 15). It becomes. Furthermore, in the case of the spark ignition type engine 11, the theoretical cycle is the Otto cycle, so that the thermal efficiency improves as the compression ratio increases.

<Engine>
The engine 11 is a diesel or spark ignition engine and is a four-stroke engine that repeats four cycles (intake, compression, combustion / expansion, and exhaust). In the case of a spark ignition engine, the engine 11 includes a plurality of cylinders, a piston that reciprocates in the cylinder, a crankshaft 12 that is connected to the piston via a connecting rod, an intake valve that is linked to the crankshaft 12, and An exhaust valve and a spark plug that is electronically controlled by the controller 70 are provided. The output of the engine 11 (rotation speed, torque, exhaust gas flow rate, etc.) is controlled by a controller 70 that controls the intake amount of fuel / air and the ignition timing.
In the present embodiment, the engine 11 is controlled to operate at a compression ratio of 13 or more.

Note that such an engine 11 has a smaller energy loss due to operation / stop as compared with a turbine, and its size (displacement) can be easily changed in design. Further, the engine displacement, the number of cylinders (2 cylinders, 4 cylinders, 6 cylinders, etc.) and the arrangement (V type, in-line type, etc.) can be changed as appropriate.

<Generator>
The generator 13 is a device that operates by the power of the engine 11 to generate electric power. Specifically, the generator 13 is mechanically connected to the crankshaft 12 of the engine 11 via an acceleration or deceleration mechanism and a clutch (not shown). Thereby, the motive power of the engine 11 is transmitted to the generator 13 without loss, and is converted into electric power by the generator 13.
Note that the power generated by the generator 13 is supplied to the power distribution device 51. Further, a power storage device that appropriately charges / discharges electric power may be provided between the generator 13 and the power distribution device 51.

<Compressor>
The compressor 14 is operated by the power of the engine 11 and compresses the hydrogen from the separator 42 and / or the electrolyzer 60 to increase the pressure to a predetermined pressure (for example, several MPa to several tens of MPa). It is a device that pumps toward external hydrogen demanding equipment such as battery cars and hydrogen tanks. Specifically, the compressor 14 is mechanically connected to the crankshaft 12 of the engine 11 via an acceleration or deceleration mechanism and a clutch (not shown). As a result, the power of the engine 11 is transmitted to the compressor 14 without loss and is converted into hydrogen fluid energy by the compressor 14.

Here, a configuration in which the compressor 14 is connected to the crankshaft 12 and operates using the engine 11 as a power source is illustrated. However, for example, the compressor 14 includes an electric motor, and the generator 13 It is good also as a structure which the said electric motor rotates and the compressor 14 act | operates when this electric power is supplied. Also in this configuration, the compressor 14 is operated by the power of the engine 11.

In addition, a plurality of compressors 14 may be connected in series, and hydrogen compressed by one compressor 14 may be further compressed by another compressor 14 to boost the hydrogen stepwise.
Furthermore, in the case of this configuration, a buffer tank may be further provided between one compressor 14 and the other compressor 14 so that a hydrogen storage alloy is incorporated and hydrogen is temporarily stored. If the buffer tank is provided in this way, hydrogen can be supplied to the other compressor 14 described above at a stable rate. A buffer tank is provided with a heater that operates with electric power from the generator 13, and the ON / OFF control of the heater may be performed to control hydrogen storage / release by the hydrogen storage alloy.

Next, the intake side of the engine 11 will be described.
From the pipe 21 a whose upstream end is open to the outside air, the turbocharger 21, the pipe 21 b (intake port), and the intake port of the engine 11 are connected in this order from the pipe 21 a toward the engine 11. The pipe 21a includes an air cleaner that removes dust and the like, a throttle valve that controls the flow rate of air, a fuel injector that injects toluene from the tank 43, and an oxygen injector that injects oxygen from the electrolyzer 60 (all not shown). Is provided.

Since high octane toluene is supplied to the engine 11 in this manner, knocking is less likely to occur in the engine 11, and the engine 11 can be operated at a high compression ratio (13 or more) to increase combustion efficiency. .

In addition, oxygen is supplied to the engine 11 by electrolysis of water in the electrolyzer 60 through the pipe 60b and the oxygen injector. That is, in the present embodiment, the “oxygen supply means for supplying oxygen generated by the electrolyzer 60 to the engine 11” includes a pipe 60b and the oxygen injector.
Since oxygen is supplied in this way, the output of the engine 11 and the amount of exhaust heat energy are improved, and the amount of power generated by the generator 13 and the amount of hydrogen generated by the reactor 30 can be increased. Become.

In addition, it is good also as a structure which provides the flow control valve which controls the flow volume of oxygen, and the buffer tank which stores oxygen temporarily in the piping 60b.
Alternatively, a hydrogen injector may be attached to the pipe 21b, and the hydrogen separated by the separator 42 may be added (injected) by the hydrogen injector.

<Supercharger>
The supercharger 21 is a device that operates by the exhaust gas discharged from the engine 11, compresses air taken into the engine 11, and supercharges the engine 11. Thus, the air is supercharged to the engine 11 by the supercharger 21, that is, the flow rate of the intake air is increased, so that the torque generated by the engine 11 is improved, and the thermal efficiency and output of the engine 11 are improved. It is supposed to be.

Next, the exhaust side of the engine 11 will be described.
The exhaust gas outlet of the engine 11 is connected to the exhaust gas inlet of the reactor 30 through a pipe 21c, a supercharger 21, and a pipe 21d. The exhaust gas from the engine 11 is led to the reactor 30 after operating (rotating) the supercharger 21.

<Reactor>
As shown in FIG. 2A, the reactor 30 includes a plurality of reaction cells 31 whose outer shape has a columnar shape, and a cylindrical first casing 32 that houses the plurality of reaction cells 31. . MCH (methylcyclohexane, hydrogen-containing fuel) flows through each reaction cell 31, and high-temperature exhaust gas flows outside the reaction cell 31 and through the first casing 32. In FIG. 1, only one reaction cell 31 is shown.

The first casing 32 and the second casing 34 which will be described later are made of metal (for example, SUS) so as to have high thermal conductivity. In addition, the shape of the 1st casing 32 and the 2nd casing 34 is not limited to a cylindrical shape, For example, a square cylinder shape and a polygonal cylinder shape may be sufficient.

<Reaction cell>
As shown in FIG. 2B, the reaction cell 31 includes a plurality of stacked reaction sheets 33 and a second casing 34 that accommodates the plurality of reaction sheets 33.

As shown in FIG. 2 (c), each reaction sheet 33 includes a base metal foil 35, a porous layer 36 formed on each surface of the metal foil 35, and a catalyst 37 supported on the porous layer 36. And. That is, each reaction sheet 33 has a three-layer structure in which the porous layer 36 supported by the catalyst 37, the metal foil 35, and the porous layer 36 supported by the catalyst 37 are stacked in this order.
In addition, a gap through which MCH, generated hydrogen, and toluene can flow is formed between the reaction sheets 33 adjacent to each other in the thickness direction.

Also, since the reaction sheet 33 is in the form of a sheet, its heat capacity is small, heat is quickly conducted through the reaction sheet 33, and the temperature of the catalyst 37 is quickly raised to a temperature at which the catalyst functions well. Thereby, the efficiency of the decomposition reaction which decomposes | disassembles MCH into hydrogen and toluene is high.

Furthermore, each reaction sheet 33 is formed with a plurality of through holes 33a. Thereby, the heat of exhaust gas is conducted well in the thickness direction, and MCH, generated hydrogen, and toluene flow well in the thickness direction.

The metal foil 35 is made of, for example, an aluminum foil and has a thickness of about 50 to 200 μm.
However, the metal foil 35 may not be provided, or instead of the metal foil 35, a porous layer serving as a base may be provided, and the entire reaction sheet 33 may have a porous structure.

The porous layer 36 is a layer for supporting the catalyst 37 and has a plurality of pores through which MCH, generated hydrogen, and toluene can flow. Such a porous layer 36 is made of an oxide mainly composed of alumina, for example.

Catalyst 37 is a catalyst for decomposing MCH, that is, dehydrogenating to produce hydrogen and toluene (see formula (1)). Such a catalyst 37 is composed of at least one selected from, for example, platinum, nickel, palladium, rhodium, iridium, ruthenium, molybdenum, rhenium, tungsten, vanadium, osmium, chromium, cobalt, iron and the like.

Note that the exhaust gas flowing through the reactor 30 is discharged to the outside through the pipe 21e (see FIG. 1).

<MCH supply system>
Next, an MCH supply system for supplying MCH to the reactor 30 will be described with reference to FIG. The MCH supply system includes a tank 41 that stores MCH.

The tank 41 is a tank that temporarily stores MCH as a raw material for hydrogen generation. The MCH is transported to the tank 41 by, for example, a tank lorry.
And MCH of the tank 41 is supplied in each reaction cell 31 through the piping 41a. The pipe 41a is provided with a pump that pumps MCH and a flow rate control valve that controls the flow rate of the MCH.

<Hydrogen / toluene derivation system>
Next, a hydrogen / toluene derivation system for deriving hydrogen and toluene produced in the reactor 30 will be described. The hydrogen / toluene lead-out system includes a separator 42 and a tank 43.

The hydrogen (gas) and toluene (gas) produced in each reaction cell 31 are led out to the separator 42 through the pipe 42a while being mixed.

The separator 42 is a device that separates hydrogen and toluene.
The separator 42 according to the present embodiment cools a mixture of hydrogen and toluene by air cooling so that only toluene (boiling point: 110 ° C.) is liquefied and hydrogen and toluene are separated. . Therefore, for example, on the outer peripheral surface of the separator 42, heat radiating fins (not shown) are provided for promoting air-cooling.
The separation method is not limited to this, and other methods such as a pressure swing adsorption device or a hydrogen permeable membrane (such as a Pd membrane) that selectively permeate hydrogen may be used.

The hydrogen separated by the separator 42 is supplied to the compressor 14 or the engine 11 (pipe not shown) through the pipe 42b. In addition, the structure provided with the pump which pumps hydrogen into the piping 42b may be sufficient.

On the other hand, the toluene separated by the separator 42 flows through the pipe 42c extending from the bottom of the separator 42 by its own weight, and is stored in the tank 43. In addition, the structure provided with the pump (not shown) which pumps toluene into the piping 42c may be sufficient.

The toluene in the tank 43 passes through the pipe 43a and is then injected into the pipe 21b (intake port) by a fuel injector (not shown) controlled by the controller 70. The pipe 43a is provided with a pump (not shown) that pumps toluene.

<Power distribution device>
The power distribution device 51 is a device that distributes the power generated by the generator 13 to the electrolyzer 60 and the external power grid 52 in accordance with a command from the controller 70 in accordance with the amount of power required from the outside. There are various electronic circuits.

For example, when the required power amount input to the controller 70 increases, the power distribution device 51 is controlled so that the power distribution amount to the power system network 52 increases. In addition, when the required hydrogen amount input to the controller 70 is zero or can be generated by the reactor 30, the power distribution device 51 is controlled to supply power only to the power grid 52. Is done.

Further, when the buffer tank for temporarily storing hydrogen is provided, for example, the pressure of hydrogen in the buffer tank is detected via a pressure sensor, and the amount of hydrogen stored is calculated based on the detected pressure. However, when the buffer tank is full, the power distribution device 51 may be configured to supply power only to the power system network 52.

<Electrolysis device>
The electrolyzer 60 operates in accordance with a command from the controller 70, electrolyzes water using the electric power from the power distribution device 51 (the generator 13) (see formula (2)), and generates hydrogen and oxygen. It is a device to do. Therefore, the electrolyzer 60 includes a positive electrode (anode) and a negative electrode (cathode), a container for temporarily storing water to be electrolyzed, a voltage controller for controlling a voltage applied to the positive electrode and the negative electrode, and the like. Moreover, the water to be electrolyzed is appropriately supplied from, for example, tap water.

2H ₂ O → 2H ₂ + O ₂ (2)

Then, the generated hydrogen is supplied to the compressor 14 through the pipe 60a, or a pipe or other equipment (for example, another compressor connected downstream of the compressor 14) that connects the compressor 14 and the hydrogen automobile. ). On the other hand, the produced oxygen is supplied to the pipe 21b (engine 11) through the pipe 60b.

<Controller>
The controller 70 is a control device that electronically controls the hydrogen station 1, and includes a CPU, a ROM, a RAM, various interfaces, an electronic circuit, and the like, and performs various functions according to programs stored therein. In addition, various devices are controlled.
The controller 70 is electrically connected to the engine 11, the generator 13, the compressor 14, the power distribution device 51, and the electrolysis device 60, and is connected to sensors and signal input devices provided in each device by wiring. It is preferable. Also, other devices (compressor, filling machine, hydrogen tank, lighting device, etc.) in the hydrogen station 1 are connected in the same manner.
Further, the controller 70 is input with a required power amount and a required hydrogen amount from the outside via an operation panel (not shown) or the like.

≪Operation and effect of hydrogen station≫
According to such a hydrogen station 1, the following operations and effects are obtained.
Hydrogen is obtained by electrolysis using the electric power from the reactor 30 that generates hydrogen by dehydrogenating MCH using the heat of the exhaust gas from the engine 11 and the generator 13 linked to the engine 11. A large amount of hydrogen can be produced by the electrolyzer 60 that generates the hydrogen.
That is, since hydrogen is generated using the exhaust gas and electric power output from the engine 11 (the generator 13), the engine 11 and the reactor 30 can be downsized, and the hydrogen station 1 can be reduced in scale.

On the other hand, when the electrolyzer 60 is not provided, all the hydrogen is generated in the reactor 30. Therefore, it is necessary to enlarge the reactor 30 and the engine 11 for supplying exhaust gas to the reactor 30, As a result, the hydrogen station becomes large.

≪Modification≫
As mentioned above, although one Embodiment of this invention was described, this invention is not limited to this, For example, it can change as follows.

In the above-described embodiment, the case where the power generation means that generates electric power and high-temperature exhaust gas with the operation is configured to include the engine 11 and the generator 13 is exemplified. The configuration may be a fuel cell or a solid oxide fuel cell. Moreover, it may replace with the engine 11 and the structure provided with a turbine may be sufficient.

1 Hydrogen station (energy generation system)
11 Engine (power generation means)
13 Generator (power generation means)
30 reactor (hydrogen generation means)
51 Power distribution device (power distribution means)
52 Electric power system network 60 Electrolysis device (electrolysis means)
60b Piping (oxygen supply means)
70 controller (control means)

Claims

An energy generation system for generating electricity and hydrogen,
Power generation means for generating electric power and high-temperature exhaust gas in operation,
Hydrogen generation means for generating hydrogen by dehydrogenating the hydrogen storage medium using heat of the high-temperature exhaust gas from the power generation means,
Electrolysis means for electrolyzing water with electric power from the power generation means to generate hydrogen and oxygen;
An energy generation system comprising:
The power generation means includes: an engine that burns combustion fuel to generate power and exhaust gas; and a generator that operates by the power generated by the engine to generate electric power. The energy generation system according to item.
The said hydrogen production | generation means produces | generates hydrogen and a high octane number fuel by carrying out the dehydrogenation reaction of the hydrogen storage body. The energy generation system of Claim 2 characterized by the above-mentioned.
The combustion fuel combusted by the engine is at least one selected from gasoline, light oil, kerosene, heavy oil, biofuel, alcohol, city gas, natural gas, LPG, and the high octane fuel generated by the hydrogen generating means. It is a seed | species. The energy generation system of Claim 3 characterized by the above-mentioned.
The energy generation system according to claim 2, wherein the engine operates at a compression ratio of 13 or more.
The energy generation system according to claim 2, further comprising oxygen supply means for supplying oxygen generated by the electrolysis means to the engine.
The power distribution unit that distributes the electric power generated by the power generation unit to the electrolysis unit and a power grid based on a required power amount and a required hydrogen amount. Energy generation system.