JP4363969B2 - Hydrogen production equipment - Google Patents

Description

  The present invention relates to a hydrogen production apparatus for producing hydrogen by steam reforming dimethyl ether using heat of a nuclear power plant.

  In order to prevent global warming, the demand for hydrogen is expected to increase significantly in the future. Therefore, hydrogen production methods are diversified and a safe and efficient hydrogen production method is required. Conventionally, steam production of petroleum, LNG (liquefied natural gas), and LPG (liquefied petroleum gas) has been the mainstream in hydrogen production, but steam reforming requires high temperature conditions of 700 ° C. or higher, which is expensive for the system. A high temperature resistant material is required.

  In addition, a desulfurization apparatus is necessary to remove the sulfur content. In addition, there is a method for producing hydrogen by electrolysis of water. However, it is currently expensive to produce and is not suitable for mass production "Physical properties of hydrogen and functionalization and application of reaction", P328-350, 2001. , Has been pointed out in the construction of Ishikawajima Plant.

  On the other hand, steam reforming of dimethyl ether (hereinafter abbreviated as DME) is proposed as a method for producing hydrogen at a low temperature and at low cost (see, for example, Non-Patent Document 1). DME steam reforming is effective because it can be reformed at a low temperature of 300 ° C compared to petroleum, LNG, and LPG raw materials, but there is a need to establish a hydrogen production system that can produce a large amount of hydrogen at low cost and high efficiency. It has been.

Further, a hydrogen production system is proposed in which natural gas component methane is decomposed into carbon and hydrogen by heat, or DME that can be synthesized from natural gas is steam reformed to generate hydrogen (see, for example, Patent Document 1).
JP 2003-165704 A (refer to page 1 to page 5 and FIG. 5) Proceedings of the 79th Annual Meeting of the Chemical Society of Japan, “Steam reforming of dimethyl ether with copper catalyst” 2J203 (2001)

  In order to safely and inexpensively produce hydrogen, it is necessary to operate a hydrogen production system at a low temperature, but steam reforming of DME is considered a promising method because it can produce hydrogen at a low temperature of 300 ° C. Therefore, it is desired to provide an efficient hydrogen production apparatus at a lower cost.

  In the steam reforming of DME, preheating is performed before DME is introduced into the reactor. However, when DME is introduced into the reactor, DME may be thermally decomposed by preheating to generate methane. Since this methane has a steam reforming temperature of 700 ° C or higher, if DME is thermally decomposed into methane, it will be a factor to reduce the hydrogen production rate at low temperatures, "Hydrogen physical properties, functionalization of reaction and application", P328-350, 2001, indicated by Ishikawajima Plant Construction. For this reason, it is necessary to suppress the methanation of DME during preheating.

  The present invention has been made to cope with such a conventional situation, and an object thereof is to provide a hydrogen production apparatus capable of producing hydrogen by steam reforming DME efficiently at a lower cost. To do.

In order to achieve the above object, a hydrogen production apparatus according to the present invention includes, as described in claim 1, a dimethyl ether supply unit that supplies dimethyl ether as a gas, an evaporator that supplies water vapor, and the dimethyl ether supply unit. A preheater filled with a copper-based catalyst or activated alumina as a heat storage body , wherein dimethyl ether supplied from the above and steam supplied from the evaporator are mixed to preheat the mixed gas at 250 ° C. to 300 ° C., and the preheater A reformer that reforms the mixed gas preheated in step to generate a hydrogen-rich gas, and a hydrogen purification unit that purifies the hydrogen-rich gas generated in the reformer to obtain a hydrogen having a required concentration, That at least one of the dimethyl ether supply unit, the evaporator, the preheater, the reformer, and the hydrogen purification unit is configured to use the heat of the nuclear power plant. It is an butterfly.

  In the hydrogen production apparatus according to the present invention, hydrogen can be produced by steam reforming DME efficiently at lower cost.

  Embodiments of a hydrogen production apparatus according to the present invention will be described with reference to the accompanying drawings.

  FIG. 1 is a configuration diagram showing an embodiment of a hydrogen production apparatus according to the present invention.

  The hydrogen production apparatus 1 includes a DME supply unit 2, an evaporator 3, a preheater 4, a reformer 5, and a hydrogen purification unit 6. The DME supply unit 2, the evaporator 3, the preheater 4, the reformer 5, and the hydrogen purification unit 6 of the hydrogen production apparatus 1 are provided so as to be able to exchange heat with the nuclear power plant 7 and to control the temperature.

  The DME supply unit 2 has a function of supplying DME as a gas to the preheater 4. For this reason, when DME is supplied to the DME supply unit 2 in a liquid state, the DME is vaporized by holding the DME at 0 ° C. or higher by using the heat 11 from the nuclear power plant 7. The DME can be supplied to the preheater 4.

  Here, as the nuclear power plant 7, a light water reactor, a fast breeder reactor, a high temperature gas reactor, a boiling water reactor, or a pressurized water reactor can be applied.

  The evaporator 3 has a function of supplying water vapor to the preheater 4. For this reason, when the water 12 is supplied to the evaporator 3, the heat 11 from the nuclear power plant 7 is used to evaporate the water 12 and supply the water vapor to the preheater 4. The temperature of the evaporator 3 is preferably 150 ° C. or higher in order to completely evaporate the water 12. When the evaporator 3 does not reach 150 ° C. or more only with the heat 11 of the nuclear power plant 7, the evaporator 3 is appropriately heated from the outside using the combustion heat of one or both of the carbon-containing fuel and the hydrogen-containing fuel. Is preferred.

  The preheater 4 mixes DME and steam, uses the heat 11 of the nuclear power plant 7 to preheat the mixed gas of DME and steam from 250 ° C. to 300 ° C., and the premixed DME and steam mixed gas To the reformer 5. When the preheater 4 does not reach 250 ° C. or more only with the heat 11 of the nuclear power plant 7, the preheater 4 is appropriately heated from the outside using the combustion heat of one or both of the carbon-containing fuel and the hydrogen-containing fuel. Is preferred.

  In FIG. 1, reference numeral 11 indicates heat introduced from the nuclear power plant 7 and is usually selected from a heat medium such as steam, gas, or pressurized water generated in a nuclear reactor. Reference numeral 13 denotes heat used in each device and guided to the nuclear power plant 7 and is usually in the form of condensate, but of course may be introduced into the nuclear power plant 7 in the form of steam, gas, or pressurized water. .

  FIG. 2 is a reaction formula when DME is thermally decomposed to generate hydrogen.

  Equation 1 in FIG. 2 is an equation showing a reaction when DME is thermally decomposed into methane, carbon monoxide and hydrogen, and Equation 2 is an equation when hydrogen is produced by steam reforming the produced methane. is there. The reaction of Formula 1 and Formula 2 requires a temperature of 700 ° C. or higher. Therefore, it can be seen that if DME is thermally decomposed into methane, it causes a decrease in the hydrogen production rate at low temperatures.

  FIG. 3 is a diagram showing the relationship between the methane production rate from DME in the preheater 4 and the steam addition ratio.

In FIG. 3, the vertical axis represents the methane (CH ₄ ) production rate, and the horizontal axis represents the addition ratio of water vapor (H ₂ O). The marks ●, ▲, ■, and ◆ are data showing the relationship between the methane production rate and the steam addition ratio when the preheating temperatures are 350 ° C., 300 ° C., 250 ° C., and 200 ° C., respectively. According to FIG. 3, it can be seen that it is preferable to set the preheating temperature to 250 to 300 ° C. in order to suppress the methanation of DME.

  Moreover, methanation can be suppressed by filling the preheater 4 with a copper catalyst or activated alumina used for steam reforming of DME as a heat accumulator.

  The reformer 5 is filled with a copper catalyst or activated alumina used for steam reforming of DME. The reformer 5 has a function of reforming a preheated DME and steam mixture gas at 250 ° C. to 300 ° C. for the same reason as in the case of preheating using the heat of the nuclear power plant 7 to generate a hydrogen rich gas. And a function of supplying the generated hydrogen-rich gas to the hydrogen purification unit 6. When the reformer 5 does not reach 250 ° C. or more only with the heat of the nuclear power plant 7, the preheater 4 is heated from the outside using the combustion heat of one or both of the carbon-containing fuel and the hydrogen-containing fuel as appropriate. Is preferred.

  FIG. 4 is a reaction formula when steam reforming DME.

  In the reformer 5, a hydrogen rich gas is generated from a preheated mixed gas of DME and water vapor by a two-stage reaction of Formula 3 and Formula 4 in FIG. First, methanol is generated from DME and water vapor by the reaction of Equation 3 in FIG. Furthermore, hydrogen and carbon dioxide are produced from methanol and water vapor by the reaction of Equation 4 in FIG.

  Here, activated alumina is used as a catalyst in the reaction in which methanol is generated from DME of formula 3 and water vapor, and copper is used as a catalyst in the reaction in which hydrogen and carbon dioxide are generated from methanol and water vapor of formula 4 respectively. Can do.

  FIG. 5 is a reaction formula showing the two-step reaction of FIG. 4 as one formula.

  That is, Formula 5 shown in FIG. 5 shows a reaction formula when steam reforming DME. According to Equation 5, it can be seen that the amount of steam used in steam reforming of DME is three times that of DME in terms of molar ratio.

  The hydrogen purifying unit 6 has a function of purifying hydrogen having a required concentration according to the purpose of use from the hydrogen rich gas using the heat 11 of the nuclear power plant 7. The hydrogen purification unit 6 is provided with, for example, a carbon monoxide transformer 8. The carbon monoxide converter 8 has a function of converting carbon monoxide contained in a hydrogen-rich gas generated by refining hydrogen into carbon dioxide. And when the carbon monoxide transformer 8 is provided in the hydrogen purification part 6, it is comprised so that hydrogen may be refine | purified from a hydrogen rich gas by a carbon monoxide combustion method. At this time, the concentration of carbon monoxide used for hydrogen generation is set according to the purpose and concentration of hydrogen. For example, when hydrogen is used in a fuel cell, the concentration of carbon monoxide is set to 10 ppm or less.

  The heat required for hydrogen purification in the hydrogen purification unit 6 is the heat of the nuclear power plant 7, but it is necessary to set the temperature to 250 ° C. for hydrogen production by the carbon monoxide combustion method. When the carbon monoxide converter 8 does not reach 250 ° C. or more only by the heat of the nuclear power plant 7, the carbon monoxide converter 8 is appropriately used by using the combustion heat of one or both of the carbon-containing fuel and the hydrogen-containing fuel. It is preferable to heat from the outside.

  Further, the hydrogen purifier 6 is provided with a water vapor remover 9 for removing water vapor contained in the hydrogen rich gas and a carbon dioxide remover 10 for removing carbon dioxide contained in the hydrogen rich gas as necessary. Then, water vapor removal, carbon dioxide removal, unreacted DME removal, intermediate organism methanol removal, and methane removal are appropriately performed. Examples of the carbon dioxide removal include an amine method, a carbon dioxide separation membrane, and a PSA method (pressure fluctuation adsorption separation method), and a format corresponding to the purpose of use can be selected.

  When all or part of the evaporator 3, the preheater 4, the reformer 5, and the hydrogen purification unit 6 are heated from the outside using the combustion heat of the hydrogen-containing fuel, the hydrogen purified in the hydrogen purification unit 6 is used. Hydrogen-containing fuel can also be produced using Furthermore, when all or a part of the evaporator 3, the preheater 4, the reformer 5, and the hydrogen purification unit 6 are heated from the outside, generation of carbon dioxide is prevented by using hydrogen purified by the hydrogen purification unit 6. You can also.

  Next, the operation of the hydrogen production apparatus 1 will be described.

  First, DME is supplied to the DME supply unit 2. When the DME is liquid, the DME is vaporized by maintaining the DME at 0 ° C. or higher using the heat 11 from the nuclear power plant 7 in the DME supply unit 2. Then, DME is supplied from the DME supply unit 2 to the preheater 4 as a gas.

  On the other hand, water or water vapor is supplied to the evaporator 3. When the water 12 is supplied to the evaporator 3, water vapor is generated in the evaporator 3 by evaporating the water 12 using the heat 11 from the nuclear power plant 7. The temperature of the evaporator 3 is about 150 ° C. or higher in order to completely evaporate the water 12. If the evaporator 3 does not exceed 150 ° C. only by the heat 11 of the nuclear power plant 7, the carbon-containing fuel and hydrogen are appropriately contained. Heated from the outside by the combustion heat of one or both of the fuels. The steam generated in the evaporator 3 is given to the preheater 4.

  Next, the preheater 4 preheats the mixed gas of DME and water vapor to 250 ° C. to 300 ° C. using the heat 11 of the nuclear power plant 7. When the preheater 4 does not reach 250 ° C. or more only by the heat 11 of the nuclear power plant 7, the preheater 4 is heated from the outside by the combustion heat of one or both of the carbon-containing fuel and the hydrogen-containing fuel as appropriate. Further, the preheater 4 supplies the reformer 5 with a premixed mixed gas of DME and steam.

  Next, in the reformer 5, using the heat of the nuclear power plant 7, the mixed gas of preheated DME and water vapor is controlled at 250 ° C. to 300 ° C. to be reformed to generate hydrogen rich gas. When the reformer 5 does not reach 250 ° C. or more only by the heat of the nuclear power plant 7, the reformer 5 is heated from the outside by appropriately using the combustion heat of one or both of the carbon-containing fuel and the hydrogen-containing fuel. It is done. Further, the hydrogen rich gas is given to the hydrogen purification unit 6.

  Next, in the hydrogen purification unit 6, hydrogen having a concentration corresponding to the purpose of use is purified from the hydrogen-rich gas using the heat of the nuclear power plant 7. The hydrogen purification unit 6 is provided with, for example, a carbon monoxide transformer 8, and purifies hydrogen from a hydrogen rich gas by a carbon monoxide combustion method. At this time, the concentration of carbon monoxide used for hydrogen generation is set according to the purpose and concentration of hydrogen. For example, when hydrogen is used in a fuel cell, the concentration of carbon monoxide is set to 10 ppm or less. The

  In addition, the hydrogen purifier 6 is provided with a water vapor remover 9 and a carbon dioxide remover 10 as necessary to remove water vapor and carbon dioxide contained in the hydrogen rich gas.

  The heat required for hydrogen purification in the hydrogen purification unit 6 is the heat of the nuclear power plant 7, but it is necessary to set the temperature to 250 ° C. for hydrogen production by the carbon monoxide combustion method. When the carbon monoxide converter 8 does not reach 250 ° C. or more only with the heat of the nuclear power plant 7, the carbon monoxide converter is externally used by appropriately using the combustion heat of one or both of the carbon-containing fuel and the hydrogen-containing fuel. 8 is heated.

  Furthermore, the hydrogen refined in this way is supplied to a demand destination such as a hydrogen station, and a part of the hydrogen is entirely contained in the evaporator 3, the preheater 4, the reformer 5, and the hydrogen purification unit 6 as necessary. Or while being utilized as a hydrogen containing fuel for heating a part from the outside, it is utilized for generation | occurrence | production prevention of a carbon dioxide.

  According to the hydrogen production apparatus 1 as described above, the DME is steam reformed by using surplus heat in the nuclear power plant 7 to efficiently produce the hydrogen by steam reforming the DME at a lower cost. be able to. At this time, by appropriately controlling the temperature in heat exchange between the nuclear power plant 7 and the hydrogen production apparatus 1, hydrogen can be produced safely at a low temperature.

  Furthermore, according to the hydrogen production apparatus 1, by controlling the preheating temperature of DME, methanation of DME can be suppressed and the hydrogen production ability at low temperatures can be improved.

  That is, if the raw material gas DME is supplied to the reformer 5 without being preheated, the temperature of the DME is not sufficient, leading to a decrease in the hydrogen production rate. Therefore, it is possible to avoid a decrease in the hydrogen production rate. On the other hand, if the preheating temperature is too high, DME is thermally decomposed and methanated, and a temperature of 700 ° C. or higher is required in order to produce hydrogen by steam reforming.

  On the other hand, in the hydrogen production apparatus 1, since the preheating temperature is controlled to 250 ° C. to 300 ° C., it is possible to suppress a decrease in the hydrogen production rate at low temperatures due to methanation of DME.

  Furthermore, in the hydrogen production apparatus 1, since the preheater 4 is filled with a copper-based catalyst or activated alumina used for steam reforming of DME as a heat accumulator, the effect of suppressing methanation is improved.

The block diagram which shows embodiment of the hydrogen production apparatus which concerns on this invention. Reaction formula when DME is thermally decomposed to generate hydrogen. The figure which shows the relationship between the methane production | generation rate from DME in a preheater, and water vapor | steam addition ratio. Reaction formula when steam reforming DME. FIG. 5 is a reaction formula showing the two-stage reaction of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Hydrogen production apparatus 2 DME (dimethyl ether) supply part 3 Evaporator 4 Preheater 5 Reformer 6 Hydrogen purification part 7 Nuclear power plant 8 Carbon monoxide converter 9 Steam remover 10 Carbon dioxide remover 11 Introduced from a nuclear power plant Heat 12 Water 13 Heat used in each equipment and guided to the nuclear power plant

Claims (7)

A dimethyl ether supply unit for supplying dimethyl ether as a gas, an evaporator for supplying water vapor, dimethyl ether supplied from the dimethyl ether supply unit and water vapor supplied from the evaporator are mixed to obtain a mixed gas at 250 ° C to 300 ° C. A preheater filled with a copper catalyst or activated alumina as a heat storage body, a reformer that reforms the mixed gas preheated by the preheater to generate a hydrogen-rich gas, and a reformer that generates the heat. A hydrogen purifying unit that purifies the hydrogen-rich gas obtained to obtain a hydrogen having a required concentration, and at least one of the dimethyl ether supply unit, the evaporator, the preheater, the reformer, and the hydrogen purifying unit generates heat from the nuclear power plant. A hydrogen production apparatus configured to be used. The hydrogen production apparatus according to claim 1, wherein a carbon monoxide converter that converts carbon monoxide contained in the hydrogen-rich gas into carbon dioxide is provided in the hydrogen purification section. A carbon monoxide converter that converts carbon monoxide contained in the hydrogen-rich gas into carbon dioxide, a water vapor remover that removes water vapor contained in the hydrogen-rich gas, and carbon dioxide contained in the hydrogen-rich gas are removed in the hydrogen purification section. The hydrogen production apparatus according to claim 1, further comprising a carbon dioxide remover . The at least one of the said dimethyl ether supply part, an evaporator, a preheater, a reformer, and a hydrogen purification part is comprised so that it may heat from the outside using the combustion heat of a hydrogen containing fuel. Hydrogen production equipment. The at least one of the said dimethyl ether supply part, an evaporator, a preheater, a reformer, and a hydrogen purification part was comprised so that it might heat from the outside using the combustion heat of a carbon containing fuel. Hydrogen production equipment. At least one of the dimethyl ether supply unit, the evaporator, the preheater, the reformer, and the hydrogen purification unit is heated from the outside using the combustion heat of the hydrogen-containing fuel generated by using the hydrogen purified in the hydrogen purification unit. The hydrogen production apparatus according to claim 1, which is configured as described above. The hydrogen generator according to claim 1, wherein the reformer is configured to reform the mixed gas at 250 ° C to 300 ° C.

Images