JPS5946882B2 - Metal hydride reaction measurement device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a metal hydrogenation reaction measuring device for measuring the hydrogenation reactivity of a metal hydride for controlling the hydrogenation reaction and dehydrogenation reaction of a metal hydride.

Many metals or alloys are known to react reversibly with hydrogen.

That is, Q is the heat of reaction). When hydrogen is stored, heat is generated, and when hydrogen is released, heat is absorbed.

Each metal or alloy has a unique hydrogen equilibrium pressure whose logarithm and reciprocal of absolute temperature have a linear relationship, as shown in FIG.

Also, as shown in Figure 2, the hydrogen equilibrium pressure of metals or alloys is
At a constant temperature, there is a region where the pressure is constant regardless of the degree of hydrogenation reaction (hydrogen storage amount), and this is called the plateau region.

In this specification, hydrides of metals or alloys and those in which hydrogen is released from the hydrides to become metallic are collectively referred to as metal hydrides.

Until now, metal hydrides include La-Ni alloy, Mm-
Ni alloy (Mm is Mitshu Metal), Mg-Ni alloy,
Fe-Ti alloy, Mg-'AI alloy, Ti-A1 alloy, etc. have been reported.

These metal hydrides utilize their hydrogen storage capacity, reaction reversibility, and large reaction heat to be used in hydrogen storage devices, heat exchange devices, heat transfer devices, air-conditioning/heating water supply devices, waste heat recovery heat devices,
Applied to thermal energy mechanical (electrical) energy conversion devices, etc.

When controlling the operation of a device that uses metal hydrides like the one above, the problem is how much hydrogen the metal hydride in the reactor stores compared to the maximum storage amount, that is, the hydrogenation rate. The problem is that it is difficult to measure the degree of reactivity in an immediate manner.

As a result, it is not possible to determine the extent to which the metal hydride should be heated, pressurized, cooled, or depressurized, or the timing for switching from heating and pressurization to cooling and depressurization is missed.
It may not be possible to sufficiently extract the reaction heat or pressure difference from the metal hydride.

Conventional equipment for measuring the hydrogenation reactivity of metal hydrides uses a gas flow meter to measure the flow rate of hydrogen gas entering and exiting a reaction vessel filled with metal hydrides, and measures the hydrogen gas pressure. was calculating the amount of hydrogen stored in.

However, gas flow meters have slow response and poor accuracy.
Calculation of the amount of absorbed hydrogen is also complicated, and the gas flow meter is also expensive.

The present inventor attempted to solve the above-mentioned conventional problems, and as a result of intensive studies, by detecting the volume change of metal hydride that occurs as the metal hydride absorbs hydrogen, the hydrogenation reactivity of metal hydride can be immediately determined. We have completed a metal hydride reaction measuring device that can measure responsively and accurately.

Figure 3 is an example of a device using metal hydride 1.
Two reaction vessels 2, 3, 4 filled with metal hydride 1.
Two sets of air-conditioning and heating blocks are provided in which 5 are connected to each other, and each reaction vessel is connected to a high-temperature heat source TH1, a medium-temperature heat source TM, and a low-temperature heat source T.
L can be connected, and one container of each set is heated alternately.
This is a heating and cooling device that can alternately use the other container as a heating and cooling source by cooling the container.

For example, CaNi as the metal hydride 1 is added to the reaction vessel 2.3.
5. A case will be described in which the reaction vessels 4 and 5 are filled with LaNi5 as a metal hydride and cooled.

The reaction vessels 2, 3, 4.5 are each provided with a heat exchange section 6,
It is connected to a heat source via a heat medium circulation pump P.

Reaction container 2 is a high temperature heat source TH, reaction container 3 is a medium temperature heat source TM.
, the reaction vessel 4 is a low temperature heat source TL, and the reaction vessel 5 is a medium temperature heat source T.
Although it is connected to M, it is possible to switch to a different heat source.

Reaction vessels 2 and 5 and reaction vessels 3 and 4 are communicated through a communication pipe 7.

A valve 8 is provided in the middle of the communication pipe 7 and can be opened and closed, and a filter 9 allows hydrogen gas to flow and prevents the metal hydride 1 from moving to another container.

Since the metal hydride 1 is self-pulverized to a size of several microns, the filter 9 is made of a metal sintered body or the like and has a tear penetration capacity of about 2 microns.

For example, when this air-conditioning system is operated by inputting a heat source of 80°C to the high-temperature heat source TH and a heat source of 40°C to the medium-temperature heat source TM, the reaction vessel 4 is Alternatively, LaNi5 of the metal hydride 1 in the reaction vessel 5 releases hydrogen and absorbs heat from the low-temperature heat source TL serving as the cooling load, thereby producing cold heat of about 15°C.

In the operation of this heating and cooling system, the temperature of the reaction vessel 2°3 is
aNi5 is heated by the high-temperature heat source TH to release hydrogen, is cooled by the medium-temperature heat source TM to absorb hydrogen, and is also heated by the reaction vessel 4,
LaNi 5 of No. 5 is cooled by the medium temperature heat source TM to release hydrogen, and heated by the low temperature heat source TL (h chamber load) to absorb hydrogen, which are alternately repeated.

During hydrogen absorption and desorption, the metal hydride 1 has a maximum hydrogen storage capacity Vo, which varies between metal hydride compositions ranging from 2 to 0.8, but the hydrogenation reactivity of the metal hydride 1 is It is difficult to determine this in real time, and there is a problem in that the timing for switching between heating and cooling of the metal hydride 1 is missed.

Metal hydride 1 is in a fine powder state, and when it is in a state where it has absorbed hydrogen to the maximum from a metal state, it has an apparent volume of 20 to 25%.
increase

The present inventor paid attention to this point and discovered that the hydrogenation reactivity of the metal hydride 1 can be measured by detecting the volumetric expansion of the metal hydride 1.

The metal hydride reaction measuring device is provided inside the vessel walls 10 of the reaction vessels 4 and 5 in the heating and cooling system shown in FIG.

Its detailed structure is shown in FIG.

A cylindrical wall 11°11 is provided inside the container integrally with the container wall 10, and walls 12, 12 are provided so as to close the opening of the cylindrical body.
is provided.

The wall 12 is made of, for example, a metal sintered body, and is made to be permeable to hydrogen gas but not permeable to metal hydride.

A reaction measurement chamber 13 and a blank chamber 14 are formed by the cylindrical wall 11 and the wall body 12 .

Hydrogen gas does not permeate into the reaction measurement chamber 13 and the blank chamber 14, and the reaction measurement chamber 13 and the blank chamber 14 are partitioned off by elastically deformable partition walls 15, 15 whose peripheral edges are fixed.

The partition wall 15.15 is preferably made of a thin plate of stainless steel or the like.

The metal hydride 16 is filled between the wall 12 and the partition wall 15 of the reaction measurement chamber 13 with no apparent gap.

If the metal hydride 16 is the same type as the metal hydride 1, no conversion is necessary for measuring the hydrogenation reactivity.

The partition wall 15 of the reaction measurement chamber 13 is elastically deformed around the center in response to hydrogen gas pressure and changes in the volume of the metal hydride 16.

The partition wall 15 of the blank chamber 14 is elastically deformed in response to changes in hydrogen gas pressure.

The space between the partition wall 15.degree. 15 and the container wall 10 may be airtight or may be communicated with the outside air.

The partition wall 15 is provided with a deformation detection element 17 for the partition wall 15 .

The space between the partition wall 15 and the wall 12 is kept at the same hydrogen gas pressure as the reaction vessel 4, and since the reaction measurement chamber 13 is formed inside the reaction vessel 4, the atmosphere is at the same temperature. The reaction conditions are the same as those for the metal hydride 1 in the reaction vessel 4.

The change in volume of the metal hydride 16 is corrected by the deformation detection element 17 of the partition wall 15 of the blank chamber 14, and the change in volume of the metal hydride 16 is detected in real time by the deformation detection element 17 of the partition wall 15 of the reaction measurement chamber 13. Hydrogenation and response of hydride 1 are measured.

As the deformation detection element 17 of the partition wall 15, a strain gauge, an inductance displacement transducer, a capacitance displacement transducer, a differential transformer, a resistance transducer, or the like is used.

FIG. 5 shows another example of a metal hydride reaction measuring device.

A hydrogen gas permeable section 18 is provided in a portion of the cylindrical wall 11 of the reaction measurement chamber 13 closer to the container wall 10 than the partition wall 15, through which hydrogen gas permeates, but through which the metal hydride 1 does not permeate.

Therefore, since the hydrogen gas is the same on both sides of the partition wall 15, there is no need to correct changes in hydrogen gas pressure.

Experimental Example A cylindrical wall 11 with an outer diameter of 24 mm and an inner diameter of 20 mm is provided inside the reaction vessel 4 made of stainless steel, and a stainless steel metal sintered wall 11 is provided inside the reaction vessel 4 made of stainless steel so as to close the opening at the tip of the cylindrical wall 11. A body wall 12 (2μ filtration capacity) is provided.

A partition wall 15 made of a thin stainless steel plate with a thickness of 1 mm is provided at a distance of 10 mm from the wall body 12, and a metal hydride LaNi516.8,
! li' was filled to apparently fill the space.

Polyimide foil strain gauge B-FAE, -5-12 manufactured by Shinko Tsushin Kogyo ■ is used as the deformation detection element 17 of the partition wall 15 on the partition wall 15.
was attached, and the deformation of the partition wall 15 was detected by the amount of strain using a strain gauge.

The relationship between the hydrogen storage amount and the strain amount was confirmed by setting the strain amount to O when the hydrogen storage amount of LaNi5 was 0.

When the maximum hydrogen storage amount of L a N 15 is 1, when the hydrogen storage amount is 0.2, the strain amount is 0.0097, and the hydrogen storage amount is 0.
8, the amount of distortion was 0.0388.

As shown in FIG. 6, the results showed that a linear relationship was established, and it was confirmed that the hydrogen reactivity of the metal hydride could be measured by the change in the volume of the metal hydride.

As described above, the metal hydride reaction measuring device of the present invention can measure the hydrogenation reactivity of metal hydrides in an instant response manner, and facilitates the operation and control of systems and devices that utilize metal hydride reactions. can be done.

Furthermore, the device of the present invention measures the volume change of a metal hydride in a reaction measurement chamber using a part of the metal hydride as a sample inside the metal hydride reaction vessel, and the reaction conditions are such that a metal hydride reaction is required. It has the advantage that it is the same as a container, has a simple structure, is inexpensive, has high reliability, and does not require a complicated calculation process.

[Brief explanation of drawings]

Figure 1 is a hydrogen pressure-temperature diagram of a metal hydride, Figure 2 is a hydrogen pressure-metal hydride composition diagram, and Figure 3 is a cross section showing an air conditioning system using the metal hydride reaction measuring device of the present invention. 4 and 5 are cross-sectional views showing essential parts of an example of the metal hydride reaction measuring device of the present invention, and FIG. 6 is a metal hydride composition showing the experimental results of the metal hydride reaction measuring device of the present invention.
It is a strain amount diagram. 1...Metal hydride, 2,3,4,5...
...Metal hydride reaction vessel, 6...Heat exchange section,
7...Communication pipe, 8...Valve, 9...
... Filter, 10 ... Reaction vessel wall, 1
1... Cylindrical wall, 12... Wall that permeates hydrogen gas but does not permeate metal hydride, 13...
...Reaction measurement chamber, 14...Blank chamber, 15.
. . . Elastically deformable partition wall, 16 . . . Metal hydride, 17 . . . Deformation detection element for partition wall 15,
18...Hydrogen gas permeation section, TH...High temperature heat source, TM...Medium temperature heat source, TL...
Low temperature heat source, P... Heat medium circulation pump.

Claims (1)

[Claims] 1. A reaction measurement chamber having a wall through which hydrogen gas permeates but not metal hydride is formed inside a metal hydride reaction container filled with metal hydride, and inside the reaction measurement chamber there is formed an elastically deformable wall. a partition wall is provided, a metal hydride is filled between the partition wall and a wall that allows hydrogen gas to pass through but not metal hydride, and a deformation detection element for the elastically deformable partition wall is provided in the reaction measurement chamber. A metal hydride reaction measuring device characterized by: