JP5269426B2 - Hydrogen generation system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a hydrogen generation system which sufficiently uses an adsorption function of an adsorption tower with a simple structure, and efficiently and economically generates hydrogen. <P>SOLUTION: A hydrogen generation system 10 includes; a water electrolysis apparatus 14 for producing high-pressure hydrogen by electrolyzing water; a first gas-liquid separator 18 for removing a water content contained in the high-pressure hydrogen; and an adsorption device 22 for removing the water content contained in the high-pressure hydrogen by adsorption. The adsorption device 22 includes a first adsorption tower 42a and a second adsorption tower 42b which are arranged in series along a hydrogen-flowing direction, and has a dew-point hygrometer 46 arranged in between the first adsorption tower 42a and the second adsorption tower 42b. <P>COPYRIGHT: (C)2009,JPO&amp;INPIT

Description

  The present invention relates to a hydrogen generation system including a water electrolysis unit that electrolyzes water to generate hydrogen and an adsorption device that adsorbs and removes moisture contained in the generated hydrogen.

  In recent years, a system for supplying electric power or power using hydrogen as a fuel, for example, a fuel cell system has been proposed. In this type of system, a water electrolysis apparatus that generates hydrogen (and oxygen) by electrolyzing water is used to produce hydrogen as a fuel.

  In this water electrolysis apparatus, hydrogen containing water is produced, and in order to obtain a dry state, for example, 5 ppm or less of hydrogen (hereinafter also referred to as dry hydrogen), it is necessary to remove the water from the hydrogen. Therefore, for example, a hydrogen station disclosed in Patent Document 1 is known.

  As shown in FIG. 3, this hydrogen station includes a water electrolysis apparatus 1 that produces hydrogen containing water, a dehydrator 2 that obtains dry hydrogen by removing moisture from the hydrogen, and the dry hydrogen. When the function is reduced due to an increase in the amount of water taken away by the tank 3 to be stored and the water removal device 2, a new water remover 2 having a water removal ability to be exchanged with the water remover 2, and the original removal after the replacement A regeneration facility 4 is provided for regenerating the water vessel 2 and recovering its water-capturing ability.

  The water electrolysis apparatus 1 is operated by the electric power supplied from the solar cell 5 to produce hydrogen, and this hydrogen is sent to the dehydrator 2 in a state of containing moisture, and the moisture is taken away, and the hydrogen is removed. Hydrogen is introduced into the tank 3.

  Then, when the amount of water taken away by the dewatering device 2 increases and its function decreases, a new dewatering device 2 is replaced with an operating dewatering device 2 whose function has been decreased. On the other hand, in the regeneration facility 4, the original dehydrator 2 is regenerated.

JP 2002-155386 A

  By the way, in the above dehydrator 2, as shown in FIG. 4, when the dewatering function is present, the water is reduced at a stroke and hydrogen containing water is supplied to the tank 3. On the other hand, the hydrogen stored in the tank 3 needs to be maintained at a desired dry hydrogen (for example, 5 ppm or less hydrogen) as a product gas. For this reason, normally, the water remover 2 is replaced | exchanged comparatively at an early stage in the period which has a water removal function, and the reproduction | regeneration process of the said water remover 2 is performed frequently.

  However, in the regeneration process of the dehydrator 2, heat energy and purge hydrogen are consumed, and this regeneration process is frequently performed. Therefore, there is a problem in that loss energy increases and hydrogen generation efficiency decreases. .

  The present invention solves this type of problem, and with a simple configuration, the adsorption function of the adsorption tower can be utilized as much as possible, and hydrogen production can be performed efficiently and economically. The purpose is to provide a system.

  The present invention relates to a hydrogen generation system including a water electrolysis unit that electrolyzes water to generate hydrogen, and an adsorption device that adsorbs and removes moisture contained in the generated hydrogen.

  The adsorption device has two or more adsorption towers arranged in series along the hydrogen flow direction downstream of the water electrolysis unit, and dew point detection means arranged at least upstream of the adsorption tower arranged at the most downstream side. I have.

  Moreover, it is preferable that a pressure adjusting valve for increasing the pressure of hydrogen generated from the water electrolysis unit is disposed between the water electrolysis unit and the adsorption device. Thereby, high-pressure hydrogen of 1 MPa to 70 MPa is obtained.

  Further, a gas-liquid separation unit that removes moisture from the produced hydrogen and a cooler that cools the hydrogen located downstream of the gas-liquid separation unit are arranged between the water electrolysis unit and the adsorption device. It is preferable to be provided.

  Furthermore, it is preferable that the adsorption tower arranged at least on the most downstream side is set to have a smaller volume than other adsorption towers on the upstream side.

  According to the present invention, the hydrogen produced by the water electrolysis unit is removed of the contained water via the upstream adsorption tower constituting the adsorption device. When the adsorption function of the upstream adsorption tower is lowered, it is detected that the upstream adsorption tower is in a saturated state via the dew point detection means. For this reason, the adsorption tower on the upstream side can utilize its adsorption function as much as possible, and the regeneration process of the adsorption tower can be effectively reduced. Thereby, reduction of the heat energy consumed for the regeneration process and improvement of the efficiency of hydrogen generation can be easily achieved.

  Moreover, the two or more adsorption towers are arranged in series along the hydrogen flow direction. Therefore, after the saturation state of the upstream adsorption tower is detected, hydrogen containing a large amount of moisture is introduced into the downstream adsorption tower to remove the moisture. Accordingly, hydrogen containing a large amount of moisture is not supplied as a product gas, and the hydrogen generation process can be performed efficiently and economically with a simple configuration.

  FIG. 1 is a schematic configuration explanatory diagram of a hydrogen generation system 10 according to the first embodiment of the present invention.

  The hydrogen generation system 10 is supplied with pure water generated from city water via a pure water supply device 12, and electrolyzes the pure water to produce high-pressure hydrogen and a water electrolysis device (water electrolysis unit) 14. , A first gas-liquid separator (gas-liquid separator) 18 for removing water contained in the high-pressure hydrogen led out from the water electrolysis device 14 to the hydrogen lead-out path 16, and hydrogen from the first gas-liquid separator 18. An adsorption device 22 that adsorbs and removes moisture contained in hydrogen supplied to the supply path 20 and a controller 23 that controls the operation of the entire hydrogen generation system 10 are provided.

  The water electrolysis device 14 is configured by stacking a plurality of water decomposition cells 24. The water splitting cell 24 uses a solid polymer electrolyte membrane to decompose water and generate hydrogen (and oxygen), and an electrolyte membrane / electrode structure in which electrode catalyst layers are provided on both sides of the solid polymer electrolyte membrane. Make up the body. Power feeding bodies are disposed on both sides of the electrolyte membrane / electrode structure, and are configured substantially in the same manner as a fuel cell.

  Pipes 26 a, 26 b and 26 c are connected to one end of the water splitting cell 24 in the stacking direction. The pipes 26 a and 26 b communicate with the pure water supply device 12 to circulate pure water, while the pipe 26 c is connected to the first gas-liquid separator 18 through the hydrogen lead-out path 16. One end of a pure water circulation path 28 is connected to the first gas-liquid separator 18, and the pure water circulation path 28 is connected to a pipe 26 a of the water electrolysis apparatus 14 via the pure water supply device 12. . A drain valve 30 communicating with the pure water circulation path 28 is provided at the bottom of the first gas-liquid separator 18.

  The hydrogen supply path 20 is located between the first gas-liquid separator 18 and the adsorption device 22, and along the flow direction of hydrogen gas, the first pressure adjustment valve 32, the cooler 34, and the second gas-liquid separation. A container 36 is provided.

  The first pressure adjustment valve 32 has a function of increasing the pressure of hydrogen generated from the water electrolysis device 14 to a predetermined pressure, for example, 35 MPa. A depressure line 38 is connected to the inlet side of the first pressure regulating valve 32 via an on-off valve 40.

  The cooler 34 reduces the amount of water contained in the hydrogen by cooling the hydrogen supplied from the first gas-liquid separator 18 to, for example, 5 ° C. The second gas-liquid separator 36 has a function of removing water separated from hydrogen by the cooler 34. In the second gas-liquid separator 36, a pure water circulation path 28a is provided with a drain valve 30a. Connected.

  The adsorption device 22 adsorbs water vapor (moisture) contained in hydrogen by a physical adsorption action, and the first adsorption tower 42a and the second adsorption tower filled with a moisture adsorbent regenerated by evaporating and desorbing moisture by heating. 42b. As the moisture adsorbent, for example, activated carbon, synthetic zeolite, porous alumina, or silica is used. As the first adsorption tower 42a and the second adsorption tower 42b, a heating adsorption tower of a TSA (Thermal Swing Adsorption) apparatus is usually used.

  The first adsorption tower 42a and the second adsorption tower 42b are arranged in series along the hydrogen flow direction (arrow A direction), and the second adsorption tower 42b has a smaller volume than the first adsorption tower 42a. Is set. Cylindrical first heaters 44a and second heaters 44b are arranged around the first adsorption tower 42a and the second adsorption tower 42b. A catalytic combustion unit (not shown) may be employed instead of the first heater 44a and the second heater 44b.

  A dew point meter (dew point detection means) 46 is disposed between the first adsorption tower 42a and the second adsorption tower 42b. The dew point meter 46 detects that the first adsorption tower 42a has reached a saturated state, that is, that the first adsorption tower 42a has not achieved a desired adsorption function. Valves 48 a and 48 b are provided at the inlet and outlet of the first adsorption tower 42 a, and the first adsorption tower 42 a can be removed from the hydrogen supply path 20.

  A dry hydrogen supply path 50 is provided on the outlet side of the second adsorption tower 42 b via a second pressure adjustment valve 49. The dry hydrogen supply path 50 is provided with a high-pressure tank 52 and a fuel supply path 54 is branched via a valve 56. The fuel supply path 54 is provided with a vehicle filling portion 58, and a fuel tank (not shown) of the fuel cell vehicle 60 can be filled with hydrogen as fuel from the vehicle filling portion 58.

  The operation of the hydrogen generation system 10 configured as described above will be described below.

  First, in the pure water supply device 12, pure water is led to the pure water circulation path 28, and this pure water is supplied into the water electrolysis device 14 from the pipe 26a. In the water electrolysis device 14, water is decomposed by electricity in each water splitting cell 24 to generate hydrogen, and the first pressure regulating valve 32 is closed to directly obtain high pressure hydrogen (1 MPa to 70 MPa). . This high-pressure hydrogen can be taken out of the water electrolysis apparatus 14 through the pipe 26c. On the other hand, oxygen produced by the reaction is discharged to the outside (not shown), and used water is returned to the pure water supply device 12 through the pipe 26b.

  The relatively high-pressure hydrogen containing water vapor generated by the water electrolysis device 14 is sent to the first gas-liquid separator 18 via the hydrogen lead-out path 16. In the first gas-liquid separator 18, water vapor contained in hydrogen is separated from the hydrogen and returned to the pure water circulation path 28, while the hydrogen can be supplied to the hydrogen supply path 20.

  Therefore, the hydrogen supplied to the hydrogen supply path 20 by opening the first pressure regulating valve 32 is introduced into the cooler 34 and cooled to a predetermined temperature (for example, about 5 ° C.), and is contained in this hydrogen. Liquefied water is liquefied. Since the liquefied water is removed by the second gas-liquid separator 36, the hydrogen whose water content is further reduced is sent to the adsorption device 22.

  In the adsorption device 22, the valves 48a and 48b are opened, and hydrogen is introduced into the first adsorption tower 42a arranged at the most upstream. In the first adsorption tower 42a, water vapor contained in hydrogen is adsorbed to obtain dry hydrogen (hereinafter, also referred to as dry hydrogen), which passes through the second adsorption tower 42b and becomes dry hydrogen. It is led out to the supply path 50.

  The dry hydrogen led out to the dry hydrogen supply path 50 is stored in the high-pressure tank 52, while a part of the dry hydrogen is supplied to the fuel supply path 54 under the opening action of the valve 56 as required. The fuel cell vehicle 60 is filled from the filling unit 58.

  Next, when the first adsorption tower 42a reaches the limit adsorption amount, the first adsorption tower 42a is saturated and hydrogen containing water is introduced into the second adsorption tower 42b. Detected through.

  For this reason, the hydrogen production process by the water electrolysis apparatus 14 is temporarily stopped, the valves 48a and 48b are closed, and the first adsorption tower 42a is removed from the hydrogen supply path 20, and the first adsorption tower 42a is regenerated. Is given. The first adsorption tower 42a subjected to the regeneration process or the new first adsorption tower 42a prepared in advance is connected to the hydrogen supply path 20, and the hydrogen generation process by the water electrolysis apparatus 14 is resumed.

  In this case, in the first embodiment, the first adsorption tower 42a and the second adsorption tower 42b are arranged in series along the hydrogen flow direction (arrow A direction), and the second arranged at the most downstream. A dew point meter 46 is disposed upstream of the adsorption tower 42b. For this reason, after the first adsorption tower 42a reaches the saturated state, the hydrogen gas containing the moisture amount equal to or more than the specified amount is favorably desorbed by the second adsorption tower 42b. Therefore, hydrogen gas containing moisture is not supplied as a product gas to the high-pressure tank 52 side, and desired dry hydrogen can be supplied to the high-pressure tank 52 side for a certain period.

  Thereby, the adsorption function of the first adsorption tower 42a can be utilized as much as possible, and the regeneration process of the first adsorption tower 42a can be effectively reduced. For this reason, while reducing the heat energy consumed for the regeneration process of the 1st adsorption tower 42a, the effect that improvement in hydrogen production efficiency is achieved is acquired.

  Furthermore, since the water electrolysis device 14 generates high-pressure hydrogen of 35 MPa, for example, the amount of water contained in the unit hydrogen molecule can be greatly reduced as compared with the case of generating normal-pressure hydrogen. The amount of water contained in the hydrogen gas depends only on the temperature. For example, when the operating temperature of the water electrolysis apparatus 14 is about 60 ° C., the amount of water contained in the 0.1 MPa hydrogen gas is 35 MPa. The amount of water contained in the hydrogen gas is 6000 times or more for the same hydrogen molecular weight.

  In other words, the amount of water contained in the high-pressure hydrogen gas is significantly lower than the amount of water contained in the normal-pressure hydrogen gas, thereby greatly extending the adsorption life of the first adsorption tower 42a. For this reason, compared with the case where the 1st adsorption tower 42a is used for the reproduction | regeneration process of a hydrogen gas of a normal pressure, lifetime is extended over about 6000 time with the same quantity of adsorbent, and the frequency of a reproduction | regeneration process is greatly increased. There is an advantage that it is reduced.

  In addition, since the life of the first adsorption tower 42a is greatly extended, the first adsorption tower 42a can be effectively downsized. Furthermore, since the second adsorption tower 42b is not always used for moisture adsorption processing, the second adsorption tower 42b can be set to a smaller volume than the first adsorption tower 42a. Thereby, there is an effect that the entire adsorption device 22 can be greatly reduced in size and simplified.

  Furthermore, in the first embodiment, a first pressure adjustment valve 32 and a second pressure adjustment valve 49 are provided. Therefore, by closing the first pressure adjustment valve 32 and the second pressure adjustment valve 49, the inside of the first adsorption tower 42a and the second adsorption tower 42b can be maintained at a high pressure, and is generated from the water electrolysis device 14. It is possible to satisfactorily suppress the influence of the flow fluctuation of the generated hydrogen gas.

  FIG. 2 is a schematic configuration explanatory diagram of a hydrogen generation system 70 according to the second embodiment of the present invention. In addition, the same referential mark is attached | subjected to the component same as the hydrogen generation system 10 which concerns on 1st Embodiment, and the detailed description is abbreviate | omitted.

  The hydrogen generation system 70 includes an adsorption device 72, and the adsorption device 72 includes a first adsorption tower 74a, a second adsorption tower 74b, and a third adsorption tower 74c that are arranged in series along the hydrogen flow direction. Cylindrical first heater 76a, second heater 76b, and third heater 76c are arranged around the first adsorption tower 74a, second adsorption tower 74b, and third adsorption tower 74c.

  A dew point meter 46 is arranged upstream of the third adsorption tower 74c arranged on the most downstream side, that is, between the third adsorption tower 74c and the second adsorption tower 74b. In addition, you may arrange | position the dew point meter 46 between the 1st adsorption tower 74a and the 2nd adsorption tower 74b as needed. The third adsorption tower 74c is set to have a smaller volume than the first adsorption tower 74a and the second adsorption tower 74b.

  In the second embodiment configured as described above, the hydrogen generated in the water electrolysis apparatus 14 is first removed from the moisture under the adsorption action of the first adsorption tower 74a, and then dried as the second adsorption tower 74b and the dry hydrogen. It is supplied to the high-pressure tank 52 side through the third adsorption tower 74c.

  When the first adsorption tower 74a exceeds the limit adsorption amount, the hydrogen containing moisture passes through the first adsorption tower 74a and is introduced into the second adsorption tower 74b, and the moisture is adsorbed. For this reason, dry hydrogen is obtained in the second adsorption tower 74b, and this dry hydrogen is supplied as product gas to the high-pressure tank 52 side through the third adsorption tower 74c.

  Further, when the second adsorption tower 74b exceeds the limit adsorption amount, the dew point meter 46 detects that the first adsorption tower 74a and the second adsorption tower 74b are saturated, while the hydrogen gas containing moisture is It introduce | transduces into the 3rd adsorption tower 74c. Therefore, in the third adsorption tower 74c, moisture in the hydrogen can be removed, and it is possible to prevent hydrogen gas containing moisture from being supplied as a product gas to the high-pressure tank 52 side.

  Next, after the first adsorption tower 74a and the second adsorption tower 74b are taken out from the hydrogen supply path 20 and subjected to regeneration treatment, new first adsorption tower 74a and second adsorption tower 74b are added to the hydrogen supply path 20. And the hydrogen generation process is resumed.

  As a result, the first adsorption tower 74a and the second adsorption tower 74b can utilize the respective adsorption functions as much as possible, and hydrogen containing a large amount of moisture is not supplied as a product gas. . For this reason, the same effects as those of the first embodiment described above can be obtained, such as enabling the hydrogen generation process to be performed efficiently and economically with a simple configuration.

  In addition, if the dew point meter 46 is also arranged between the first adsorption tower 74a and the second adsorption tower 74b, the saturation state of the first adsorption tower 74a and the saturation state of the second adsorption tower 74b, It can be detected individually.

  Moreover, in 2nd Embodiment, although the adsorption | suction apparatus 72 employ | adopts the 3 towers serial structure of the 1st adsorption tower 74a-the 3rd adsorption tower 74c, it is not limited to this, For example, 4 tower series It is also possible to adopt a multi-column series structure such as a structure.

It is a schematic structure explanatory view of a hydrogen generation system concerning a 1st embodiment of the present invention. It is schematic structure explanatory drawing of the hydrogen production system which concerns on the 2nd Embodiment of this invention. It is explanatory drawing of the hydrogen station currently disclosed by patent document 1. FIG. It is explanatory drawing of the adsorption | suction function of an adsorption tower.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10,70 ... Hydrogen production system 12 ... Pure water supply apparatus 14 ... Water electrolysis apparatus 16 ... Hydrogen lead-out path 18, 36 ... Gas-liquid separator 20 ... Hydrogen supply path 22, 72 ... Adsorption apparatus 23 ... Controller 24 ... Water splitting cell 32, 49 ... Pressure adjusting valve 34 ... Coolers 42a, 42b, 74a-74c ... Adsorption towers 44a, 44b, 76a-76c ... Heater 46 ... Dew point meter 52 ... High pressure tank

Claims (3)

A hydrogen generation system comprising a water electrolysis unit that electrolyzes water to generate hydrogen, and an adsorption device that adsorbs and removes moisture contained in the generated hydrogen,
The adsorption device comprises two or more adsorption towers arranged in series along the flow direction of hydrogen downstream of the water electrolysis unit;
Dew point detection means disposed at least upstream of the adsorption tower disposed at the most downstream;
With
Between the water electrolysis unit and the adsorption tower disposed at the uppermost stream, a first pressure regulating valve for increasing the pressure of the hydrogen generated from the water electrolysis unit is disposed, and at the most downstream side. A hydrogen generation system, wherein a second pressure regulating valve is disposed downstream of the adsorption tower, and the inside of the adsorption tower is held at a high pressure by the first and second pressure regulating valves. 2. The hydrogen generation system according to claim 1, wherein a gas-liquid separation unit that removes moisture from the generated hydrogen is provided between the water electrolysis unit and the adsorption tower disposed in the uppermost stream .
A cooler that is located downstream of the gas-liquid separator and cools the hydrogen;
A hydrogen generation system characterized in that is provided.   3. The hydrogen generation system according to claim 1, wherein the adsorption tower disposed at least on the most downstream side is set to have a smaller volume than the other adsorption towers on the upstream side.

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