JP2019189511A - Hydrogen storage system and hydrogen storage method - Google Patents

Abstract

To provide a hydrogen storage system that can rapidly fill the transported hydrogen.SOLUTION: The hydrogen storage tank 50 includes a first tank 101 in which a first hydrogen storage alloy A is enclosed, and a second tank 102 in which a second hydrogen storage alloy B having different characteristics from the first hydrogen storage alloy A is enclosed, and in which heat exchange is performed between the first tank 101 and the second tank 102 using a refrigerant 111.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a hydrogen storage system and a hydrogen storage method.

  The Basic Energy Plan, approved by the Cabinet in April 2014, stipulates that efforts to accelerate the realization of a “hydrogen society” that uses hydrogen in daily life and industrial activities will be promoted. The active use of hydrogen at the Tokyo Olympics and the subsequent movement toward the spread of the hydrogen society are becoming more active. The introduction of the renewable energy feed-in tariff (FIT) in July 2012 markedly changed the non-residential photovoltaic power generation market (public and industrial fields). According to JPEA PV OUTLOOK 2030, the ratio of non-residentials to total domestic shipments was 50% in FY2012 (relative to the total domestic shipment amount of 3.8GW), 73% in FY2013 (relative to 8.4GW) In the first half of fiscal 2014, it has grown significantly to 77% (compared to 4.3GW of domestic shipments in the first half).

  When all of them are in operation due to a large amount of certified solar power generation facilities, there is a concern that the amount of power supplied by solar power generation will exceed the amount of power demand during light load periods when power demand is low. Therefore, system connection was made on the condition of "unlimited and uncompensated output suppression". In the future, with the further increase in the amount of solar power system connections, the implementation of output suppression for the purpose of power supply and demand adjustment is becoming a reality.

  On the other hand, in Japan, in addition to public buildings, buildings such as houses, office buildings, hospitals, etc. that significantly reduce the annual energy consumption (net zero energy building, hereinafter referred to as ZEB) We are proceeding with our efforts. The 2014 Basic Energy Plan clearly states that new public buildings, etc. will aim to achieve ZEB on average for new buildings by 2030.

  From such a social background, the amount and frequency of surplus power generated due to output suppression are expected to increase, and once CO2 free hydrogen is produced using surplus power of renewable energy, for example, when the demand for power increases Attention has been focused on technology for converting hydrogen stored in the area into electricity and using it in the city block as needed. For storing hydrogen, for example, as described in Patent Document 1, it is conceivable to use a hydrogen storage alloy.

  In such a power management system, for example, a wide area with a radius of several tens of kilometers is used as a local production for local consumption area, and a surplus power is efficiently utilized at a renewable energy power plant such as a mega-solar site located off-site. To produce high-pressure hydrogen gas. The high-pressure hydrogen gas is collected by a high-pressure hydrogen transport vehicle, and then transported to and used in a central block in the area, thereby providing a considerable amount of energy creation required for building ZEB in the block. Moreover, hydrogen production is possible by efficiently using surplus power of renewable energy such as solar power generation installed on-site in the block.

JP 2002-060201 A

  Externally procured CO2-free hydrogen is transported to the city block as high-pressure gas. At present, when a high-pressure hydrogen gas is filled in a transport container with a bundle of cylinders called “Kardle”, or when transported in large quantities, a large cylinder that can withstand a high pressure of about 20 MPa is bundled. In general, hydrogen gas is charged in a trailer for transportation. A large amount of hydrogen can be stored by transferring and storing from such a high-pressure hydrogen transport vehicle or the like to a hydrogen storage alloy tank installed in a city block or site.

  However, the maximum storage amount of hydrogen is set for each application area. When the stop time in the vicinity of a building such as a high-pressure hydrogen transport vehicle becomes long, there is a case where the maximum storage amount is violated. Therefore, it is necessary to limit the stop time of the hydrogen transport vehicle as short as possible. Therefore, rapid filling is required for transfer to the hydrogen storage alloy tank.

  In view of the above-described problems, an object of the present invention is to provide a hydrogen storage system and a hydrogen storage method capable of rapidly filling transported hydrogen.

  A hydrogen storage system according to an aspect of the present invention includes a first tank in which a first hydrogen storage alloy is sealed, and a second tank in which a second hydrogen storage alloy having different characteristics from the first hydrogen storage alloy is sealed. And heat exchange is performed between the first tank and the second tank using a refrigerant.

  A hydrogen storage method according to an aspect of the present invention includes a first tank in which a first hydrogen storage alloy is sealed, and a second tank in which a second hydrogen storage alloy having different characteristics from the first hydrogen storage alloy is sealed. The procedure for storing the transferred hydrogen in the first tank, and the hydrogen stored in the first tank by exchanging heat between the first tank and the second tank using a refrigerant. And a procedure for transferring to the second tank.

  According to the present invention, there are provided two types of hydrogen storage alloy tanks, a first tank and a second tank, in which hydrogen storage alloys having different characteristics are sealed, and the hydrogen transported from the hydrogen transport vehicle is supplied to the first tank. Then, hydrogen is transferred from the first tank to the second tank by performing heat exchange between the first tank and the second tank using a refrigerant. Thereby, the transferred hydrogen can be filled in the tank in a short time.

It is a figure which shows the installation structure of the power management system which concerns on embodiment of this invention. It is a figure which shows the structure of the hydrogen storage tank which concerns on embodiment of this invention. It is the figure which showed typically the PCT diagram from which temperature differs. It is a figure which shows the PCT characteristic of the hydrogen storage alloy selected by embodiment of this invention. It is explanatory drawing of the operation | movement procedure of the hydrogen storage system which concerns on embodiment of this invention.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a diagram showing an equipment configuration of a power management system 1 (hydrogen storage system) according to an embodiment of the present invention.

  In FIG. 1, a renewable energy power source 10 is a renewable energy power source that supplies renewable energy to a building 70, and outputs surplus power of the renewable energy to the storage battery 20 and the DC power source 30. As the renewable energy power source 10, wind power generation or the like may be used in addition to solar power generation.

  The hydrogen production apparatus 40 receives the storage battery discharge power corresponding to the charge power of the storage battery 20 and the hydrogen production power among the surplus power output from the renewable energy power supply 10 by the DC power supply 30, and uses the received power. Produce hydrogen.

  The hydrogen storage tank 50 stores the hydrogen produced by the hydrogen production apparatus 40 by causing the hydrogen storage alloy to store the hydrogen. The hydrogen storage tank 50 stores the hydrogen transported by the hydrogen transport vehicle 80 by causing the hydrogen storage alloy to store the hydrogen. The hydrogen storage tank 50 will be described in detail later.

  The fuel cell 60 generates power using the hydrogen released from the hydrogen storage tank 50 and supplies the generated power to the building 70.

  The building 70 is provided with lighting equipment, air conditioning equipment, various electric / electronic equipment, and the like. These become consumer loads that consume power.

  As described above, in the power management system 1 according to the embodiment of the present invention, the hydrogen produced by the hydrogen production apparatus 40 is stored in the hydrogen storage tank 50 and the hydrogen transported by the hydrogen transport vehicle 80 is stored. The A large amount of hydrogen can be stored by transferring and storing the hydrogen transport vehicle 80 to the hydrogen storage tank 50 installed in the city block or site. At this time, rapid filling of the hydrogen storage tank 50 is desired so that the stop time of the hydrogen transport vehicle 80 in the vicinity of the building 70 is shortened.

  FIG. 2 is a diagram showing a configuration of the hydrogen storage tank 50 according to the embodiment of the present invention. In FIG. 2, the hydrogen storage tank 50 includes two hydrogen storage alloy tanks, a first tank 101 and a second tank 102 in which two types of hydrogen storage alloys having different PCT characteristics are enclosed.

  The first tank 101 is a tank for rapidly filling hydrogen transported from the hydrogen transport vehicle 80. The first tank 101 is filled with a hydrogen storage alloy A. The hydrogen in the first tank 101 is gradually transferred to the second tank 102 by performing heat exchange between the first tank 101 and the second tank 102 using the refrigerant 111.

  The second tank 102 is a tank for storing the hydrogen produced by the hydrogen production apparatus 40 or the hydrogen transferred from the first tank 101 and sending it to the fuel cell 60. A hydrogen storage alloy B is sealed in the second tank 102.

  Here, the hydrogen storage alloy tank stores hydrogen in a compact and safe manner by enclosing the hydrogen storage alloy in the tank and storing / releasing hydrogen in the hydrogen storage alloy. The characteristics of the hydrogen storage alloy are represented by a PCT (Pressure Composition Temparature) diagram.

  FIG. 3 is a diagram schematically showing PCT diagrams at different temperatures. In FIG. 3, the X axis indicates the hydrogen storage amount, and the Y axis indicates the hydrogen gas pressure. A characteristic C1 indicates a characteristic at a temperature T degree, and a characteristic C2 indicates a characteristic at a lower temperature (T-α) degree. As shown in FIG. 3, the PCT diagram of the hydrogen storage alloy has a region where the hydrogen pressure is substantially constant. Such a region is called a plateau region.

  In FIG. 3, for example, when the temperature is cooled to the temperature (T−α) degree from the state of the point Q1 of the characteristic C1 at the temperature T degree, the state shifts to the state of the point Q2 of the characteristic C2 and hydrogen storage is started. On the contrary, when heating is performed from the state of the point Q2 of the characteristic C2 of the temperature (T-α) degree to the state of the point Q1 of the characteristic C1 of the temperature T degree, hydrogen release is started. Thus, in the hydrogen storage alloy tank, hydrogen storage is basically started by cooling and hydrogen release is started by heating.

  FIG. 4 is a diagram showing PCT characteristics of the hydrogen storage alloy A and the hydrogen storage alloy B selected in the embodiment of the present invention. In the present embodiment, the PCT characteristics of the hydrogen storage alloy A (first hydrogen storage alloy) sealed in the first tank 101 and the hydrogen storage alloy B (second hydrogen storage alloy) sealed in the second tank 102 are as follows. Is different. In FIG. 4, the characteristic C101 indicates the characteristic of the hydrogen storage alloy A when hydrogen is released, and the characteristic C102 indicates the characteristic of the hydrogen storage alloy B when hydrogen is stored. As the hydrogen storage alloy A and the hydrogen storage alloy B, those having the following characteristics are selected.

(1) The hydrogen storage alloy A has a larger hydrogen storage capacity than the hydrogen storage alloy B.
(2) At the same temperature, the hydrogen gas pressure at the start of hydrogen release of the hydrogen storage alloy A in the plateau region is higher than the hydrogen gas pressure at the start of hydrogen storage of the hydrogen storage alloy B.
(3) It is preferable that the plateau region of the hydrogen storage alloy B is flat.

  In FIG. 4, the hydrogen gas pressure indicated by Pemp is the lower limit pressure in the use region on the PCT diagram for the hydrogen storage alloy B. Therefore, at the hydrogen gas pressure Pemp, it means that the available hydrogen in the second tank 102 is “empty”. Further, the hydrogen gas pressure indicated by Pfull is the upper limit pressure of the use region on the PCT diagram regarding the hydrogen storage alloy B. Therefore, when the hydrogen gas pressure is Pfull, it means that the hydrogen storage amount of the second tank 102 is “full tank”. The storage amount between the hydrogen storage amount at the hydrogen gas pressure Pemp and the hydrogen storage amount at the hydrogen gas pressure Pfull is the effective hydrogen storage amount that can be used in the second tank 102.

  By selecting the hydrogen storage alloy A and the hydrogen storage alloy B having the above characteristics, the hydrogen transported from the hydrogen transport vehicle 80 to the first tank 101 in a short time, as will be described later. Can be filled. Further, the hydrogen stored in the first tank 101 can be easily transferred to the second tank 102.

FIG. 5 is an explanatory diagram of an operation procedure of the power management system 1 according to the embodiment of the present invention.
(Procedure S1) The hydrogen transported from the hydrogen transport vehicle 80 is transported to the first tank 101. The transfer of hydrogen to the first tank 101 is performed by using the heat supply system 110 to cool and suppress the temperature rise of the hydrogen storage alloy A accompanying rapid filling, so that the first tank 101 can be transferred from the hydrogen transport vehicle 80 in a short time. Hydrogen can be transferred to the tank. When the transfer of hydrogen to the first tank 101 is completed, the hydrogen transport vehicle 80 leaves.

(Procedure S2) Hydrogen is sequentially transferred from the first tank 101 to the second tank 102.
(A) At that time, the coolant 111 is circulated between the first tank 101 and the second tank 102, thereby cooling the second tank 102 and heating the first tank 101.
(B) The second tank 102 starts to store hydrogen when cooled, and the first tank 101 starts releasing hydrogen when heated. If this operation is continued, heat exchange is performed between the first tank 101 and the second tank 102, and the temperatures of the first tank 101 and the second tank 102 become substantially isothermal.
(C) As shown in the PCT diagram of FIG. 4, the hydrogen gas pressure at the start of hydrogen release of the hydrogen storage alloy A is higher than the hydrogen gas pressure at the start of hydrogen storage of the hydrogen storage alloy B. Move from the tank 101 to the second tank 102.
(D) In the second tank 102, the hydrogen storage amount of the hydrogen storage alloy B of the second tank 102 in the PCT diagram of FIG. 4 increases from the state of the point Q102 through a path along the characteristic C102.
(E) Similarly, the hydrogen storage alloy A in the first tank 101 discharges hydrogen from the state of the point Q101 through a path along the characteristic C101.
(F) Until both points Q101 and Q102 reach the pressure Pfull, the hydrogen storage alloy A in the first tank 101 releases hydrogen, the hydrogen storage alloy B in the second tank 102 performs hydrogen storage, and the first tank 101 The hydrogen is transferred from the fuel to the second tank 102.

  (Procedure S3) The hydrogen transferred to the second tank 102 is supplied to the fuel cell 60. The fuel cell 60 can generate power using the sent hydrogen.

  (Procedure S4) It is determined whether or not the amount of hydrogen stored in the second tank 102 exceeds a certain value. If the hydrogen storage amount of the second tank 102 exceeds a certain value (step S4: Yes), the process returns to step S3, and the supply of hydrogen from the second tank 102 to the fuel cell 60 is continued. If the hydrogen storage amount of the second tank 102 falls below a certain value (procedure S4: No), the process proceeds to procedure S5.

  (Procedure S5) It is determined whether or not the hydrogen storage amount of the first tank 101 is equal to or greater than a certain value. If the hydrogen storage amount of the first tank 101 is equal to or greater than a certain value (procedure S5: Yes), the process returns to the procedure S2, and the transfer of hydrogen from the first tank 101 to the second tank 102 is performed. When the amount of hydrogen stored in the first tank 101 falls below a certain value (procedure S5: No), the procedure returns to procedure S1, and the externally procured hydrogen is rapidly charged again.

  As described above, in the power management system 1 according to the embodiment of the present invention, the hydrogen storage tank 50 includes two types of hydrogen, the first tank 101 and the second tank 102 in which hydrogen storage alloys having different PCT characteristics are enclosed. It has a storage alloy tank. Thereby, the hydrogen transported from the hydrogen transport vehicle 80 can be filled in a short time. As a result, it is possible to avoid restrictions on high-pressure gas storage in the building incidental, and CO2 free hydrogen procured outside can cover the energy equivalent amount necessary for ZEB conversion of the building in the block.

  Further, in the power management system 1 according to the embodiment of the present invention, the refrigerant 111 is circulated between the first tank 101 and the second tank 102 so that the hydrogen stored in the first tank 101 is the first. It can be easily transferred to the two tanks 102. In addition, while the externally procured CO2 free hydrogen is being received in the first tank 101, the power generation in the fuel cell 60 can be continued without interruption by releasing the hydrogen from the second tank 102. Also in this case, heat exchange is performed by circulating the refrigerant 111 between the first tank 101 and the second tank 102, so that no dedicated heat source is required and energy saving can be achieved.

  The embodiment of the present invention has been described in detail with reference to the drawings. However, the specific configuration is not limited to this embodiment, and includes design and the like within the scope not departing from the gist of the present invention.

10: Renewable energy power source, 50: Hydrogen storage tank, 80: Hydrogen transport vehicle, 101: First tank, 102: Second tank, 111: Refrigerant

Claims (4)

A first tank filled with a first hydrogen storage alloy;
A second tank filled with a second hydrogen storage alloy having different characteristics from the first hydrogen storage alloy;
A hydrogen storage system configured to perform heat exchange between the first tank and the second tank using a refrigerant.   2. The hydrogen storage system according to claim 1, wherein the first hydrogen storage alloy has a larger hydrogen storage capacity than the second hydrogen storage alloy.   The hydrogen storage according to claim 1 or 2, wherein a hydrogen gas pressure at the start of hydrogen release of the first hydrogen storage alloy is higher than a hydrogen gas pressure at the start of hydrogen storage of the second hydrogen storage alloy. system. Preparing a first tank enclosing a first hydrogen storage alloy and a second tank enclosing a second hydrogen storage alloy having different characteristics from the first hydrogen storage alloy;
A procedure for storing the transferred hydrogen in the first tank;
A method of performing heat exchange between the first tank and the second tank using a refrigerant and transferring the hydrogen stored in the first tank to the second tank.

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