JP2003165704A - Hydrogen production system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve a utilization efficiency of energy by manufacturing hydrogen through the use of an electricity generation system, in particular an atomic power generation system. <P>SOLUTION: Hydrogen is generated by decomposing methane, a component in a natural gas to carbon and hydrogen by heat or by reforming synthesizable dimethyl ether from the natural gas by water vapor. In the water vapor reforming of the dimethyl ether, a heat supplying line 32 to supply heat from an atomic reactor 31 as water vapor, a fuel supplying line 34 to supply a fuel composed of the dimethyl ether and water vapor and a water vapor reformer 33, are equipped. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hydrogen production system, and more particularly, to a hydrogen-containing compound such as methane using a heat generated by a power generation system, particularly a nuclear reactor or an electric heater. And a system for producing hydrogen or the like from a hydrogen-containing compound such as dimethyl ether using heat generated in a nuclear reactor or heat of an electric heater.

[0002]

2. Description of the Related Art In the twentieth century, human energy consumption has accelerated to an unprecedented rate, the ratio of nuclear power generation, natural gas, and other power generation has been increased, and energy conservation has been carried out. The energy consumed by is covered. Also, the conversion of some of the energy sources to hydrogen energy is beginning to be planned globally.

As a system for utilizing hydrogen energy,
Examples include fuel cells and hydrogen turbines. A fuel cell is a system in which hydrogen and oxygen are electrochemically reacted and electric energy generated at this time is taken out. Conventionally, automobiles burn gasoline to run, but in the future, it is considered to switch to electric automobiles using fuel cells. Further, in power generation using a turbine, petroleum, coal, and natural gas have been burned until now, but a hydrogen turbine intends to burn hydrogen.

In these hydrogen energy utilization systems, the product used is harmless water, and the hydrogen energy utilization system is expected to play a role in energy equipment in the 21st century. In particular, fuel cell vehicles and stationary fuel cells are expected to become widespread around 2020, and a large demand for hydrogen is expected, and the appearance of a large-scale hydrogen production system is awaited.

[0005]

By the way, a hydrogen utilization system such as a fuel cell or a hydrogen turbine requires hydrogen as a fuel. Hydrogen as a fuel electrolyzes water,
It is considered to generate by adding steam to methane which is a component of natural gas. A system as shown in FIG. 4 is used in the electrolysis of water. 1 is an electrolyte dissolved in water or an electrolyte containing water. As the electrolyte, there are one that dissolves in water such as sodium hydroxide and one that contains water such as a solid electrolyte. 2 is the anode,
Reference numeral 3 denotes a cathode, and oxygen generated at the anode is collected by the oxygen collector 4 and taken out from the oxygen take-out port 5. Further, the hydrogen generated at the cathode is collected by the hydrogen collector 6 and taken out from the hydrogen take-out port 7.

In electrolysis of water, the majority of the cost required is electricity. In current nuclear power generation systems and thermal power generation systems, only about 50% of the fission energy that is converted into heat and the combustion energy of oil, coal and natural gas can be converted into electricity. In particular, the heat utilization efficiency of the nuclear power generation system is 30% or more. Therefore, in the electrolysis of water using electric power, there is a problem that the energy use efficiency cannot be improved and efficiency is not high.

The present invention has been made to solve such a problem, and is methane, which is a component of natural gas heated by using heat generated by a power generation system, particularly a nuclear power generation system or heat of a heater. A hydrogen-containing compound is decomposed at a high temperature by a filler to separate carbon to produce hydrogen, and a system for producing hydrogen, etc., or dimethyl ether heated using the heat generated by a nuclear power generation system or the heat of a heater is converted into steam. It is an object of the present invention to provide a hydrogen production system that produces hydrogen by producing quality.

[0008]

In order to achieve the above object, the present invention constitutes a hydrogen production system by the following means. The invention corresponding to claim 1 uses a heat generated by a power generation system or a heater heat to decompose a hydrogen-containing compound such as methane at high temperature to separate carbon to generate hydrogen. System. The invention corresponding to claim 2 is the hydrogen production system according to claim 1, wherein the power generation system is a nuclear power generation system.

The invention corresponding to claim 3 is the hydrogen production system according to claim 1, which utilizes methane as a component in natural gas. The invention corresponding to claim 4 is the hydrogen production system according to claim 1, which utilizes methane as a component separated from the natural gas by a deep-cooling method.

The invention corresponding to claim 5 is the hydrogen production system according to claim 1, which is equipped with a hydrogen separator for generating hydrogen. The invention corresponding to claim 6 is the hydrogen production system according to claim 5, wherein the hydrogen separation device has a hydrogen permeable membrane, a hydrogen storage material, or a hydrogen permeable membrane and a pump.

The invention corresponding to claim 7 is a hydrogen production system characterized in that dimethyl ether is steam-reformed by using heat generated in a nuclear power generation system to generate hydrogen. The invention corresponding to claim 8 is the hydrogen production system according to claim 7, wherein the nuclear power generation system is any one of a light water reactor, a fast breeder reactor, a high temperature gas reactor, and a boiling water reactor.

The invention corresponding to claim 9 is the hydrogen production system according to claim 7, wherein dimethyl ether is produced by reforming at least one of natural gas and coal bed gas by steam or carbon dioxide. The invention corresponding to claim 10 is that dimethyl ether is produced by gasifying coal.
The hydrogen production system according to claim 7.

In the system for decomposing methane into carbon and hydrogen, for example, hydrogen is produced from methane without generating carbon dioxide, so that hydrogen required in the hydrogen utilization system can be taken out and natural gas can be effectively utilized. Moreover, since most of the energy required for producing hydrogen and the like is supplied by thermal energy, the energy converted into heat, particularly the fission energy, can be efficiently used. Furthermore, since dimethyl ether can be steam-reformed at a low temperature, hydrogen can be produced by utilizing a heat source of a light water reactor, a fast breeder reactor or a high temperature gas reactor, particularly a low temperature heat source. Dimethyl ether is a large-scale gas field with small and medium gas fields, coal bed gas and large CO ₂ content,
Manufactured from methane. In large-scale gas fields, natural gas is compressed / cooled and transported by LNG carrier. On the other hand, dimethyl ether can be transported by an LPG ship, which is hotter than the LNG ship at normal pressure, or by a normal tanker at room temperature, if the pressure is kept constant. Therefore, in small and medium-sized gas fields where large-scale facilities for natural gas liquefaction cannot be used, dimethyl etherification is economically more advantageous than natural gas liquefaction.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a configuration diagram showing a first embodiment of a hydrogen production system according to the present invention. Natural gas or the like is introduced from the gas inlet portion 11, and the hydrogen-containing compound 12 such as methane, which is a component of the natural gas or the like, is heated by the heating portion 13 by utilizing heat from nuclear fission or the like. A heater using electric power generated by a nuclear power generation system or the like can also be used for heating. The thermal decomposition part 14 on the downstream side of the heating part is filled with a filler 15 made of metal or the like, and when methane passes through the thermal decomposition part, for example, if it is 500 ° C., it is decomposed into carbon and hydrogen, and generated. Hydrogen is taken out from the gas outlet section 16. Also, in the nuclear reactor, the outlet temperature of the coolant that transports heat is set to 950 ° C in the gas reactor and 650 in the fast breeder reactor.
It is possible to set the temperature to ° C. In the gas furnace, the outlet temperature of the cooling gas after power generation can be set to 650 ° C.

In such a system, no carbon dioxide is generated. Further, most of the energy required for manufacturing hydrogen and the like is supplied by thermal energy and does not need to be converted into electricity, and the fission energy converted into heat can be used as it is, so it is possible to improve the energy utilization efficiency. .

FIG. 2 is a block diagram showing a second embodiment of the hydrogen production system according to the present invention. As a nuclear reactor 21,
A gas furnace using helium gas as the coolant 22 is used, the temperature of the reactor outlet 23 is set to 950 ° C., and natural gas containing the hydrogen-containing compound 12 such as methane introduced from the gas inlet portion 11 of the hydrogen gas production system 24, The heating unit 13 raises the temperature to 950 ° C. The gas introduction part may be equipped with a system (not shown) for liquefying natural gas or the like by a deep-cooling method or the like to separate methane or the like. In the process of raising the temperature of methane or the like, the temperature can be raised to 1000 ° C or higher by further heating with a heater (not shown).

Next, the thermal decomposition section 14 filled with the filling material 15
Guides natural gas to and decomposes methane, a component of natural gas, into carbon and hydrogen. The material to be filled is nickel,
It may be iron, cobalt or the like, or may be nickel, iron, cobalt or the like supported by silica, titania, graphite or the like.

Hydrogen produced by the decomposition of methane is taken out from the gas outlet 16. When hydrogen gas is taken out to this gas outlet, pure hydrogen can be taken out through a hydrogen permeable membrane (not shown) made of nickel. The material of the hydrogen permeable film may be a hydrogen permeable film made of palladium, silicon nitride or another material. Further, in order to increase the hydrogen permeation rate in the hydrogen permeable membrane, a pump or a lanthanum-nickel based hydrogen storage material can be used outside the permeable membrane. The hydrogen storage material may be a titanium-based material or the like.

In this system, hydrogen can be produced from natural gas without generating carbon dioxide, and natural gas can be effectively used. In the electrolysis of water, most of the cost required for electrolysis is electricity, and the current nuclear power generation system can convert only 30% or more of fission energy that is converted into heat into electricity. In the electrolysis of, even if the efficiency of electrolysis is 100%, only 30% of the fission energy can be used. On the other hand, in this system, the energy required for producing hydrogen etc. is supplied by thermal energy, so the fission energy converted to heat is
It can be used for several percent or more, and the fission energy can be used efficiently.

In the third embodiment of the hydrogen production system according to the present invention shown in FIG. 2, as the reactor 21, the coolant 2 is used.
A natural gas containing a hydrogen-containing compound 12 such as methane introduced from the gas inlet 11 of the hydrogen gas production system 24, using a fast breeder reactor using liquid metal such as sodium for 2 and setting the temperature of the reactor outlet 23 to 650 ° C. In the heating section 13 at 950
Raise the temperature to ℃. The gas introduction part may be equipped with a system (not shown) for liquefying natural gas or the like by a deep-cooling method or the like to separate methane or the like. In the process of raising the temperature of methane or the like, the temperature can be raised to 1000 ° C or higher by further heating with a heater (not shown).

Next, the thermal decomposition section 14 filled with the filling material 15
Guides natural gas to and decomposes methane, a component of natural gas, into carbon and hydrogen. The material to be filled is nickel,
It may be iron, cobalt or the like, or may be nickel, iron, cobalt or the like supported by silica, titania, graphite or the like.

Hydrogen produced by the decomposition of methane is taken out from the gas outlet 16. When hydrogen gas is taken out to this gas outlet, pure hydrogen can be taken out through a hydrogen permeable membrane (not shown) made of nickel. The material of the hydrogen permeable film may be a hydrogen permeable film made of palladium, silicon nitride or another material. Further, in order to increase the hydrogen permeation rate in the hydrogen permeable membrane, a pump or a lanthanum-nickel based hydrogen storage material can be used outside the permeable membrane. The hydrogen storage material may be a titanium-based material or the like.

In this system, hydrogen can be produced from natural gas without generating carbon dioxide, and natural gas can be effectively used. In the electrolysis of water, most of the cost required for electrolysis is electric power, and in the present nuclear power generation system, only 30% or more of the fission energy converted into heat can be converted into electric power. Only 30% of energy is available. On the other hand, in this system, the energy required for producing hydrogen etc. is supplied by thermal energy, so the fission energy converted to heat is
It can be used for several percent or more, and the fission energy can be used efficiently.

FIG. 3 is a block diagram of the fourth embodiment of the hydrogen production system according to the present invention. In this hydrogen production system, the steam at about 285 ° C. generated in the light water reactor 31 is supplied from the heat supply system 32 to the steam reformer 33. Also,
Dimethyl ether and steam, which are fuels for hydrogen production, pass through a heat exchanger 35 from a fuel supply device 34 and a steam reformer 33.
And is heated to about 285 ° C. The reformer is filled with a reforming catalyst such as Cu-Zn. With such a structure, dimethyl ether is easily vaporized by lowering the pressure below 70 atm, and the steam reforming reaction CH ₃ OCH ₃ + 3H ₂ O → 6H ₂ + 2CO ₂ represented by the following formula is highly modified. Quality occurs and hydrogen and CO ₂ are produced. Hydrogen and CO ₂
The reaction product such as can be taken out from the reactant recovery system 36 through the heat exchanger 35.

The separation of hydrogen and CO ₂ is or selectively absorbing CO ₂ at a CO ₂ absorbing material exemplified by zeolite, or selectively absorbing hydrogen storage material exemplified by La-Ni alloy This can be done by permeating hydrogen with a hydrogen permeable membrane exemplified by palladium (not shown).

In this system, hydrogen can be produced from dimethyl ether that can be produced from natural gas, and natural gas can be effectively used. In the electrolysis of water, most of the cost required for electrolysis is electric power, and in the present nuclear power generation system, only 30% or more of the fission energy converted into heat can be converted into electric power. Only 30% of energy is available. On the other hand, in this system, the energy required for producing hydrogen etc. is supplied by thermal energy, so the fission energy converted into heat is used.
30% or more can be used, and fission energy can be used efficiently.

As described above, hydrogen can be produced in a light water reactor by steam reforming of dimethyl ether, and highly efficient utilization of heat energy and chemical energy storage can be achieved. The present invention is not limited to light water reactors, but can be applied to fast breeder reactors and high temperature gas reactors.

By the way, dimethyl ether is pressurized (about 6
Liquefaction at room temperature by ata) makes it easy to store and transport. The receiving facility is simple and the receiving cost is expected to be equal to or less than that of LNG. At present, it is attracting attention as an alternative fuel for diesel fuel, which is a fuel for diesel engine vehicles, and can be a hydrogen transportation medium in the future. In particular, the conditions for reforming dimethyl ether are mild, about 300 ° C, which is very advantageous in terms of safety when combined with nuclear power. The use of dimethyl ether (DME) is represented by the following flow. Natural gas from small and medium-sized gas fields and coal seams → (CH ₄ reforming) → H ₂ , CO →
(DME synthesis) → DME → (liquefied tanker transportation and storage)
→ (DME reforming) → H ₂ + CO ₂ (recovery) In other words, the reforming reaction of natural gas in small and medium-sized gas fields and coal beds is CH ₄ + H ₂ O = CO + 3H ₂ CH ₄ + CO ₂ = 2CO + It is represented by 3H ₂ , and dimethyl ether is synthesized from the generated CO and hydrogen by the following reaction. 2CO + 4H ₂ = CH3OCH3 + H ₂ O 3CO + 6H ₂ = CH3OCH3 + CO ₂ This dimethyl ether is transported by a regular tanker or a liquefied tanker at a constant pressure to reform the dimethyl ether with steam. Hydrogen and CO ₂ generated at the end are separated to recover hydrogen.

[0029]

As described above, in the hydrogen production system of the present invention, methane, which is a component of natural gas or the like, can be decomposed into carbon and hydrogen using the nuclear fission energy converted into heat.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing a first embodiment of a hydrogen production system of the present invention using a nuclear reactor.

FIG. 2 is a configuration diagram showing second and third embodiments of the hydrogen production system of the present invention using a nuclear reactor.

FIG. 3 is a configuration diagram showing a fourth embodiment of a hydrogen production system of the present invention using a nuclear reactor.

FIG. 4 is a configuration diagram showing a general water electrolysis system.

[Explanation of symbols]

1 ... Electrolyte, 2 ... Anode, 3 ... Cathode, 4 ... Oxygen scavenger, 5
... Oxygen outlet, 6 ... Hydrogen trap, 7 ... Hydrogen outlet, 11 ... Gas inlet, 12 ... Hydrogen-containing compound such as methane, 13 ... Heating section, 14 ... Pyrolysis section, 15 ... Filler, 1
6 ... Gas outlet part, 21 ... Reactor, 22 ... Coolant, 23 ...
Nuclear reactor outlet, 24 ... Hydrogen gas production system, 31 ... Light water reactor, 32 ... Heat supply system, 33 ... Steam reformer, 34 ... Fuel supply device, 35 ... Heat exchanger, 36 ... Reactant recovery system.

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) H01M 8/06 H01M 8/06 RF term (reference) 4G040 DA03 DB03 EA01 EA06 EA09 EB03 EB12 FA02 FB09 FC01 FC02 FD04 FE01 5H027 AA02 BA00 DD01 DD05

Claims (10)

[Claims] 1. Using the heat generated in the power generation system,
A hydrogen production system characterized in that hydrogen is produced by decomposing a hydrogen-containing compound at a high temperature to separate carbon. 2. The hydrogen production system according to claim 1, wherein the power generation system is a nuclear power generation system. 3. The hydrogen production system according to claim 1, wherein methane, which is a component in natural gas, is used. 4. The hydrogen production system according to claim 1, wherein methane, which is a component separated from natural gas by a cryogenic method, is used. 5. The hydrogen production system according to claim 1, further comprising a hydrogen separator for generating hydrogen. 6. The hydrogen production system according to claim 5, wherein the hydrogen separation device has a hydrogen permeable membrane, a hydrogen storage material, or a hydrogen permeable membrane and a pump. 7. A hydrogen production system, characterized in that dimethyl ether is steam-reformed to produce hydrogen by using heat produced in a nuclear power generation system. 8. The hydrogen production system according to claim 7, wherein the nuclear power generation system is any one of a light water reactor, a fast breeder reactor, a high temperature gas reactor, and a boiling water reactor. 9. The hydrogen production system according to claim 7, wherein dimethyl ether is produced by reforming at least one of natural gas and coal seam gas with steam or carbon dioxide. 10. The hydrogen production system according to claim 7, wherein dimethyl ether is produced by gasifying coal.