JPH09303954A - Method and device for liquefying hydrogen by using neon - Google Patents

Abstract

PROBLEM TO BE SOLVED: To effectively and economically produce liquefied hydrogen by a method wherein after compressed and cooled low temperature high pressure hydrogen is further cooled by the latent heat of liquefied neon, the hydrogen is expanded for liquefaction. SOLUTION: Hydrogen compressed by a hydrogen compressor 14 is cooled by a heat-exchanger 15a and a liquefied nitrogen reservoir 16 and converted into approximate 17% parahydrogen concentration by an ortho-paraconverter 17. Further, the hydrogen flows through, in order, heat-exchangers 15b-15e filled with an ortho-para conversion catalyst and is cooled to approximate 28K and converted to approximate 95% hydrogen concentration. Further, after the hydrogen is expanded by a hydrogen expansion turbine 18 to generate cold, it is introduced to an ortho-paraconverter 19 in a liquefied neon reservoir 51 and converted to approximate 99% para-hydrogen concentration and simultaneously cooled to a value approximately equal to 25K. Thereafter, by effecting flashing of the hydrogen by a hydrogen J-T valve 20, the hydrogen is introduced to a liquefied hydrogen storage tank 21. Gas and liquid are separated to extract liquefied hydrogen from a product extraction route 22. Since the high feed pressure of a neon circulation cycle is effectively utilized, the efficiency of a process is improved and hydrogen is effectively and economically liquefied.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for liquefying hydrogen using neon, and more particularly to a method and an apparatus for liquefying hydrogen by using neon as a cold source for generation.

[0002]

2. Description of the Related Art As a method for liquefying hydrogen to obtain liquefied hydrogen, Japanese Patent Publication No. 3-194
The hydrogen liquefaction method described in Japanese Patent No. 71 is known.
This method has been carried out only by relying on an expansion turbine in which a generation cold source is installed in a neon circulation cycle and an expander called a concentrated fluid expander installed immediately before hydrogen liquefaction.

However, in the above-mentioned one, when the boiling point of neon is about 27K at normal pressure, the boiling point of hydrogen is as low as about 20K, and when the cold source for generating the neon circulation cycle depends only on the expansion turbine. However, the temperature at which the raw material hydrogen can be cooled is limited to around the boiling point temperature of neon of 27 K, and the inlet temperature of the expander becomes high immediately before liquefaction, resulting in an increase in flash loss.

Therefore, the present invention aims to provide a hydrogen liquefaction method and apparatus using neon, by which liquefied hydrogen can be obtained more effectively and economically by cooling hydrogen by utilizing the latent heat of neon. I am trying.

[0005]

In order to achieve the above object, a hydrogen liquefaction method using neon according to the present invention is a method of liquefying hydrogen by compressing, cooling and expanding the hydrogen. High-pressure hydrogen is characterized in that it is further cooled by the latent heat of liquefied neon obtained by compressing, cooling and expanding neon, and then expanding and liquefying, and that the liquefying neon is in a reduced pressure state, ，
When liquefying the cooled low-temperature high-pressure neon by adiabatic expansion, the temperature after expansion is set to a temperature higher than the boiling point temperature at least after the expansion and expanded by an expansion turbine or a supercritical expansion turbine, The expansion pressure in the supercritical expansion turbine is the discharge pressure (pressure after expansion)
Is above the critical pressure of the turbine fluid.

The neon-based hydrogen liquefying apparatus of the present invention is a hydrogen compressor for compressing liquefied hydrogen, a heat exchanger for cooling the compressed hydrogen, and a low-temperature high-pressure hydrogen after cooling for expansion. Means for liquefying a portion, a liquefied hydrogen storage tank for storing liquefied hydrogen generated by expansion, and hydrogen that has not been liquefied as a cooling source for the heat exchanger, and hydrogen after being used as a cooling source is the hydrogen compressor. A hydrogen circulation path for returning the gas to the suction side for circulation, a neon compressor for compressing neon, a heat exchanger for cooling the compressed neon, and an expansion means for expanding the cooled low temperature neon to liquefy a part thereof. , A liquefied neon reservoir that stores liquefied neon generated by expansion, an expansion turbine that expands a portion of the compressed neon to generate cold, a neon that has not been liquefied by the expansion in the expansion means, and the liquid A neon circulation path in which neon evaporated in the neon reservoir and neon expanded by the expansion turbine are used as cooling sources for the heat exchanger, and neon after being used as a cooling source is returned to the suction side of the neon compressor for circulation. When,
And a heat exchange means for further cooling the low-temperature high-pressure hydrogen by the liquefied neon in the liquefied neon reservoir.

Further, the hydrogen liquefaction apparatus of the present invention comprises an exhaust pump for sucking neon vaporized in the liquefied neon reservoir to reduce the pressure in the liquefied neon reservoir, and expanding the low-temperature high-pressure neon. An expansion turbine or a supercritical expansion turbine is provided in series upstream of the expansion means for liquefying the portion, and the discharge pressure (pressure after expansion) of the supercritical expansion turbine is equal to or higher than the critical pressure of the turbine fluid. It is an expansion turbine, and is characterized in that a heat exchanger for liquefied neon and an expansion turbine are provided in series upstream of an expansion means for expanding the low-temperature high-pressure hydrogen to liquefy a part thereof.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in more detail with reference to the drawings. FIG. 1 shows an example of a hydrogen liquefaction apparatus using neon of the present invention, which is composed of a hydrogen liquefaction cycle 10 and a neon circulation cycle 50.

The hydrogen liquefaction cycle 10 includes a raw material hydrogen passage 11 for supplying raw material hydrogen, and a hydrogen supply passage 13 where the raw material hydrogen supplied from the raw material hydrogen passage 11 and the circulating hydrogen from the hydrogen circulation passage 12 join together. A hydrogen compressor 14 for compressing hydrogen in the hydrogen supply path 13 to a predetermined pressure, and a plurality of heat exchangers 15a, 15b, 15c for cooling the compressed hydrogen.
15d, 15e, 15f and a liquefied nitrogen reservoir 16 provided downstream of the first-stage heat exchanger 15a for cooling compressed hydrogen to a liquefied nitrogen temperature level, and an orthopara converter immersed in the liquefied nitrogen reservoir 16 Hydrogen expansion turbine (supercritical expansion) that expands the low-temperature high-pressure hydrogen derived from the (heat exchanger) 17 and the final-stage heat exchanger 15f for high-pressure hydrogen at a pressure range higher than the critical pressure of hydrogen (about 12.7 atm). Turbine) 1
8, the orthopara converter (heat exchanger) 19 provided in the liquefied neon reservoir 51 of the neon circulation cycle 50, and these orthopara converters (heat exchangers) and the expansion turbine, the temperature became low. Hydrogen JT valve 20 which is expansion means for expanding (flushing) low temperature compressed hydrogen to liquefy a part thereof, liquefied hydrogen storage tank 21 for storing liquefied hydrogen generated by expansion, and hydrogen which has not been liquefied (flash loss ) Or hydrogen vaporized in the liquefied hydrogen storage tank 21, the heat exchangers 15a, 15b, 15c, 15d, 15e,
15 f and the hydrogen circulation path 12 for merging with the raw material hydrogen path 11 after collecting cold as a cooling source of the heat exchanger 52 at the final stage of the neon circulation cycle 50. Low temperature side heat exchangers 15b, 15 downstream from the orthopara converter (heat exchanger) 17
The hydrogen passages c, 15d, 15e, and 15f are filled with conversion catalysts for continuously ortho-para converting the passing hydrogen. Further, the liquefied hydrogen of the product is extracted from the product extraction path 22 provided in the liquefied hydrogen storage tank 21. The hydrogen expansion turbine 18 is a supercritical turbine whose pressure after expansion is its critical pressure, and the hydrogen expansion turbine 18, the heat exchanger that is the orthopara converter 19, and the hydrogen JT valve 20 are They are arranged in series.

On the other hand, the neon circulation cycle 50 includes first and second neon compressors 53 and 54 for compressing neon at room temperature to a predetermined pressure, and a plurality of heat exchangers 15a, 15b and 15c common to the hydrogen cooling. , 15d, 15e, a heat exchanger 55 immersed in the liquefied nitrogen reservoir 16, and a neon cooling liquefaction path 56 for sequentially cooling neon by the final stage heat exchanger 52, and a final stage of the neon cooling liquefaction path 56. Neon expansion turbine 57 provided upstream of the heat exchanger 52, and a neon J-T valve 58 which is an expansion means for expanding (flushing) the low temperature neon led out of the heat exchanger 52 and liquefying a part thereof. The liquefied neon reservoir 51 that stores the liquefied neon generated by expansion, the neon that has not been liquefied (flash loss), and the neon that has evaporated in the liquefied neon reservoir 51 are liquefied. Was aspirated from the on reservoir 51 by reducing the pressure in the liquefied neon reservoir 51 to a negative pressure in the exhaust pump 59
Then, the neon sucked by the exhaust pump 59 is returned to an appropriate temperature position of the heat exchanger to collect cold as a cooling source of each heat exchanger, and then returned to the suction side of the first neon compressor 53. A neon circulation path 60 for circulation, first to third neon expansion turbines 61, 62a, 62b for generating cold by branching a part of the neon flowing through the neon cooling liquefaction path 56 and performing adiabatic expansion, and After introducing neon, which has been cooled to an intermediate pressure in the neon expansion turbine 61 to generate cold, into the heat exchangers 15b and 15a having a corresponding temperature as a cooling source, the neon is joined to the suction side neon of the second neon compressor 54. The cold path 63 and the neon derived from the second neon expansion turbine 62a at an intermediate pressure are transferred to the heat exchanger 15c.
After being used as a cooling source in the second neon expansion turbine 62b, it is introduced into the third neon expansion turbine 62b, expanded to a low pressure to generate refrigeration again, and is introduced into the heat exchanger 15e. The neon of the cold path 64 merges with the neon of the neon circulation path 60 and the first neon compressor 53.
Circulates.

The neon expansion turbine 57 installed upstream of the final stage heat exchanger 52 in series with the neon JT valve 58 has a discharge temperature at least higher than the boiling temperature at that pressure. That is, it is set so that it does not liquefy at the turbine outlet, and
A supercritical expansion turbine can also be used. This supercritical expansion turbine is an expansion turbine whose discharge pressure (pressure after expansion) is equal to or higher than the critical pressure.

Liquefied nitrogen is supplied to the liquefied nitrogen reservoir 16 from a liquefied nitrogen passage 16a, and the liquefied nitrogen reservoir 1 is
The nitrogen evaporated in 6 merges with the low temperature nitrogen from the low temperature nitrogen path 16b generated in the process of producing liquefied nitrogen, is cold-collected by the heat exchanger 15a, and is then discharged from the exhaust path 16c.

In the hydrogen liquefaction cycle 10, the hydrogen compressed by the hydrogen compressor 14 to a predetermined pressure (20 to 60 atm) is cooled to the liquefied nitrogen temperature level by the heat exchanger 15a and the liquefied nitrogen reservoir 16 and at the same time. Liquefied nitrogen reservoir 16
In the ortho-para converter 17 of the heat exchanger immersed in, the para-hydrogen concentration is converted to about 17%.

Thereafter, the hydrogen is converted into the heat exchangers 15b, 15c, 15d, which have a path filled with the orthopara conversion catalyst.
By sequentially flowing through 15e, it is cooled down to about 28 K which is close to the boiling point temperature of neon at normal pressure, and the parahydrogen concentration is converted to about 95%. These heat exchangers 15b,
The cold of 15c, 15d, and 15e is mainly due to the first to third neon expansion turbines 61 of the neon circulation cycle 50,
62a and 62b.

On the other hand, neon having a predetermined pressure in the neon cooling path 56 is cooled to about 28 K by the heat exchanger 15e,
The neon expansion turbine 57 adiabatically expands to a discharge temperature higher than the boiling temperature of neon at the pressure after expansion to generate cold, and is further cooled by the heat exchanger 52, and then neon J
-T-valve 58 expands Joule-Thomson, introduces into liquefied neon reservoir 51 and separates into gas and liquid. At this time, the pressure in the liquefied neon reservoir 51 is a negative pressure state of about 0.5 atm by being sucked by the exhaust pump 59, and the temperature is 25K.
Becomes

The return gas from the liquefied neon reservoir 51 is returned to the normal pressure by the exhaust pump 59, and then merges with the neon at the substantially normal pressure in the second cold path 64 which has led out the third neon expansion turbine 62b on the low temperature side. Then, after flowing through the neon circulation path 60 and being cold-collected by the heat exchanger, it is sucked into the neon compressors 53 and 54, compressed to a predetermined pressure and circulated.

The low-temperature high-pressure hydrogen, which has been ortho-para converted by the ortho-para conversion catalyst while being cooled by the heat exchanger 15f, has at least a discharge pressure of hydrogen at the hydrogen expansion turbine 18 (about 12.7 atm). ) After expanding to a higher pressure and producing cold, liquefied neon reservoir 51
It is introduced into an orthopara converter (heat exchanger) 19 inside and is converted to a parahydrogen concentration of about 99% and at the same time cooled to nearly 25K.

The cooled hydrogen is flushed by the hydrogen J-T valve 20 and introduced into the liquefied hydrogen storage tank 21, the gas-liquid separation is performed and the liquefied hydrogen is extracted from the product extraction path 22, and the gas is the hydrogen circulation path 12 After recovering cold by passing through, it joins the raw material hydrogen passage 11.

The exhaust pump 59 need not be located near the liquefied neon reservoir 51 and can be installed at an appropriate position in the neon circulation path 60. That is, it may be installed at a position of room temperature or another temperature level, but it is disadvantageous in that a separate route is required.

[0020]

As described above, according to the present invention,
Since the latent heat of liquefied neon is utilized, hydrogen can be effectively cooled, and further, by decompressing liquefied neon, hydrogen can be cooled to a lower temperature.
In addition, before the JT expansion and liquefaction of the neon, adiabatic expansion is performed by an expansion turbine in which the discharge temperature is set to a temperature higher than the boiling point temperature at least at that pressure to generate cold, so that the neon circulation cycle is high. The supply pressure can be effectively utilized. Therefore, the efficiency of the process is improved, and hydrogen can be liquefied more effectively and economically.

[Brief description of drawings]

FIG. 1 is a system diagram showing an example of a hydrogen liquefaction device of the present invention.

[Explanation of symbols]

10 ... Hydrogen liquefaction cycle, 11 ... Raw material hydrogen path, 12 ...
Hydrogen circulation path, 13 ... Hydrogen supply path, 14 ... Hydrogen compressor, 15a, 15b, 15c, 15d, 15e, 15f
... Heat exchanger, 16 ... Liquefied nitrogen reservoir, 17 ... Orthopara converter (heat exchanger), 18 ... Hydrogen expansion turbine, 19 ... Orthopara converter (heat exchanger), 20 ... Hydrogen J-T valve, 2
DESCRIPTION OF SYMBOLS 1 ... Liquefied hydrogen storage tank, 22 ... Product extraction path, 50 ... Neon circulation cycle, 51 ... Liquefied neon storage, 52 ... Heat exchanger, 53, 54 ... First and second neon compressors, 55 ... Heat exchanger, 56 ... neon cooling liquefaction path, 57 ... neon expansion turbine, 58 ... neon JT valve, 59 ... exhaust pump,
60 ... Neon circulation path, 61, 62a, 62b ... 1st to 1st
3rd neon expansion turbine, 63, 64 ... 1st and 2nd cold path

Claims (8)

[Claims] 1. A method of liquefying hydrogen by compressing, cooling and expanding it, further cooling the compressed and cooled low-temperature high-pressure hydrogen with latent heat of liquefied neon obtained by compressing, cooling and expanding neon. After that, the hydrogen liquefaction method using neon is characterized by expanding and liquefying. 2. The hydrogen liquefaction method using neon according to claim 1, wherein the liquefied neon is in a reduced pressure state. 3. When the compressed and cooled low-temperature high-pressure neon is adiabatically expanded and liquefied, the temperature after expansion is set at a temperature higher than the boiling point temperature at least after the expansion and expanded by an expansion turbine. The method for liquefying hydrogen using neon according to claim 1, characterized in that. 4. The hydrogen liquefaction method using neon according to claim 3, wherein the expansion turbine is a supercritical expansion turbine. 5. A hydrogen compressor for compressing liquefied hydrogen,
A heat exchanger that cools the compressed hydrogen, an expansion unit that expands the cooled low-temperature high-pressure hydrogen to liquefy it, a liquefied hydrogen storage tank that stores the liquefied hydrogen generated by expansion, and a non-liquefied hydrogen. As a cooling source of the heat exchanger, a hydrogen circulation path for returning hydrogen after being used as a cooling source to the suction side of the hydrogen compressor for circulation, a neon compressor for compressing neon, and cooling the compressed neon. A heat exchanger, an expansion means for expanding the low temperature neon after cooling to liquefy a part thereof, a liquefied neon reservoir for storing the liquefied neon generated by the expansion, and a part of the compressed neon for expanding the cold. An expansion turbine to be generated, neon not liquefied by expansion in the expansion means, neon evaporated in the liquefied neon reservoir, and neon expanded in the expansion turbine as a cooling source of the heat exchanger. A neon circulation path for returning the neon after used as a cooling source to the suction side of the neon compressor for circulation, and a heat exchange means for further cooling the low-temperature high-pressure hydrogen by the liquefied neon in the liquefied neon reservoir. A hydrogen liquefaction device using neon, which is characterized in that 6. The hydrogen liquefaction apparatus using neon according to claim 5, further comprising an exhaust pump for sucking neon evaporated in the liquefied neon reservoir to reduce the pressure in the liquefied neon reservoir. 7. The hydrogen liquefaction apparatus using neon according to claim 5, wherein an expansion turbine is provided in series upstream of an expansion means for expanding the low-temperature high-pressure neon to liquefy a part thereof. 8. A heat exchanger for liquefying neon and an expansion turbine are provided in series upstream of an expansion means for expanding the low-temperature high-pressure hydrogen to liquefy a part thereof. Hydrogen liquefaction device using neon.