JPS6027602A - Preparation of high-purity hydrogen gas - Google Patents

Abstract

PURPOSE:To purify a crude hydrogen gas and to use energy of heat generation absorption, by liquefying impurities of the crude hydrogen gas to separate a purified hydrogen gas, occluding it in a hydrogen occlusion alloy and releasing it. CONSTITUTION:A raw material of a crude hydrogen gas is subjected to heat exchange with a low-temperature gas, the temperature of the gas is reduced to T4, and its pressure is also slightly lowered to P4. The pressure is lowered to P1 by repetition of adiabatic expansion, the temperature is reduced to T1, components except hydrogen in the crude hydrogen gas are liquefied, sent to a gas-liquid separator, and it is separated into a purified hydrogen gas and impurities. When the pressure of the prepared purified gas is raised P1-P3 by a compressor, the temperature is elevated from T2 to T5, further the temperature is raised to T9, and the pressure is slightly lowered to P2. The purified hydrogen gas is occluded in the alloy 2 in this state. While, the high-purity hydrogen is released from the alloy 1, absorption of heat takes place with it, and the temperature of the alloy 1 is reduced to T5. Heat generated in the alloy 2 is transferred through a heating medium to a heat engine.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in a method for producing high-purity hydrogen gas, and more particularly, the present invention relates to the improvement of a method for producing high-purity hydrogen gas, and more particularly, to the improvement of a method for producing high-purity hydrogen gas. Purification of hydrogen is carried out by 4 "Udo 1", storage L13 and IJA
III = 11', / 7shin+v lυ o-L
/ '1. K l'i'+J Lino -i/shi -L
-'tY fl'l III.

For example, what happens to the materials used in semiconductor products? :! 99.999% or 1. ：is after that, 1
1 left, 1! The demand for hydrogen has been increasing in recent years with the development of the hydrogen industry.

In order to produce such high-purity hydrogen, it is necessary to use a relatively pure raw material gas such as water electrolysis, or to use various synthetic reaction gases or COG. ,,+-
The crude hydrogen gas was taken from the furnace gas).
! Used as raw material for activated F1 carbon and synthesis! ! People like ΔLight, which uses an adsorbent to adsorb impurities and remove them, have been around for a long time. Preparation of hydrogen sludge made in 11 (31, absorption method, chemical reaction method, expanded RII method, cryogenic separation R1 method, etc.).The cryogenic separation method cools the gas.
(It is a process of condensing the impurities contained in the hydrogen, separating it into gas and liquid, and converting it into hydrogen.) This process can be combined with an adsorption method to achieve high purity. No. 49-1488).

On the other hand, as research into the absorption and desorption of hydrogen by special alloys progresses, attempts have been made to utilize them for the purification of hydrogen gas (Japanese Patent Application Laid-open No. 88803/1983). According to the disclosed method↓, two hydrogen-absorbing alloy containers are connected to each other so that they can exchange heat, one stores hydrogen, and the accompanying heat is transmitted to the other to compensate for the heat absorption that occurs when hydrogen is released. It is something.

The present inventors have combined purification of crude hydrogen gas using cryogenic separation with advanced purification using hydrogen storage alloys, and in this process, the heat generated by hydrogen storage is replaced by hydrogen gas for release of hydrogen. Instead of using it to heat the storage alloy, we came up with the idea of converting it into power using a heat engine to supplement the power necessary for compressing crude hydrogen gas for cryogenic separation, and this led to the present invention. 11:.

That is, in the method for producing high purity hydrogen gas of the present invention, impurities in the gas are liquefied by lowering the temperature of crude hydrogen gas, and purified hydrogen gas is obtained through gas-liquid separation. By occluding and releasing water into the hydrogen storage alloy, hydrogen gas with a higher Itli degree can be obtained, and the heat generated by the storage of hydrogen in the hydrogen storage alloy can be absorbed by a heat engine. Convert this power into power by ′
Gas 81 and I made by Vj are characterized by being used as power for compressing other gases. In one exemplary embodiment of the present invention, a hydrogen storage alloy is used which is generating hydrogen gas (as a low-temperature source, releasing hydrogen gas) and is therefore absorbing heat. do.

The hydrogen storage alloy is an MCI alloy, -1-i -1" a
Various types of alloys have been investigated, including 1'n tin alloys, la-a Ni 51"ri Mn s-based alloys, etc. Each alloy has a different wet a-IF force (1) bamboo, so it is difficult to carry out the method of the present invention. Then, select one suitable for the humidity of the system and other conditions under single force.

Since the heat engine utilizes the energy of a relatively low-temperature heat source, a suitable engine such as a Freon gas turbine is selected. Stirling engine engines, which have recently seen significant technological advances, are also available. Another interesting example is the so-called 1C1 thermally driven engine, which uses shape memory alloys, which have recently been the subject of much research. The concept is already known (Japanese Patent Laid-Open No. 129773/1983). It will be readily understood that for thermally driven engines, the transformation temperature of the shape memory alloy must be below the upper limit of the hydrogen storage temperature of the hydrogen storage alloy and between the lower limit of the hydrogen release temperature. . In addition, any heat source that operates from a relatively low temperature heat source may be used.

The present invention will now be described in detail with reference to the flow diagrams of the drawings. In the figure, T1 to TI2 represent the temperature of the system, and P1 to P5 represent the pressure of the system. In both cases, the higher the number, the higher the temperature or pressure.

As feedstock, crude hydrogen gas from any source, e.g.
The target is gas separated from OG.

A typical composition is usually 1-12.55%, (CH4+G
o) 35%, others 10%. The degree of change is T 1
0, set the pressure to P5.

The temperature of the crude gas is lowered to T4 by heat exchange with the lower temperature gas, and the pressure is also slightly lowered to ])4.

Then, after repeated adiabatic expansion, the pressure is reduced to P.
When the temperature is lowered to 1, the temperature is lowered by 1.

1 is a suitable temperature at which the gas component to be separated is lower than the boiling point of the gas component at the partial pressure 1.

When the humidity drops to T1, components other than hydrogen in the crude hydrogen gas liquefy and are separated into purified hydrogen and impurities by gas-liquid separation. This '3 It exchanges heat with the crude hydrogen gas to be cooled. Impurity (Ct-14
+ CO), the temperature is -1-3; '>'l'
After rising to J:l, it exits the system.

When purified hydrogen gas is compressed by increasing the LF force from 1 to P3, it becomes b'1Fnl p
3 increases from T2 to T5. Thereafter, through further heat exchange with the crude water-based gas, the temperature drops to T9, and the pressure drops slightly to P2. In this state, it is brought into contact with Alloy 2 and occluded by it. Alloy 2 generates heat as it goes μ, and its temperature decreases to T12.

On the other hand, high-purity hydrogen is released from Alloy 1, heat is absorbed accordingly, and the temperature of Alloy 1 decreases to T5. The heat generated in alloy 2 flows into the heat engine through the heat medium. Alloy 1 absorbs heat from the heat engine through the heat medium, and a heat flow is generated in the heat chamber at J:. (The temperature on the high temperature side of the heat engine is T11, and that on the low temperature side is T7.

) This heat flow is used to operate the heat engine described above, and the IJ power is used as power for the compressor.

The power generated by this heat engine may be used to increase the pressure of the purified hydrogen gas after 1llll of deep cooling as shown in the example of the flow diagram above, but the pressure of the raw material gas may be used to increase the pressure if it is low. In addition to compressing the purified hydrogen gas when it comes out of the gas-liquid molecule 111 unit Wl as in the illustrated example, the purified hydrogen gas may also be compressed after heat exchange with the crude gas. In this case, which one to select depends on the type of alloy used.

Purified hydrogen can be cooled by repeating adiabatic expansion and expansion, but up to a certain temperature it can also be cooled by using a refrigerant such as Freon, and the cooling process of this cold 7J11 funda tree. Part of the power may be power that generates heat for ilJ.

J3, the usage of the power of the heat engine is not limited to this,
High lK released from hydrogen storage alloy! For the compression of hydrogen gas, or for the compression of gas in systems other than this hydrogen refinery 59 system, and other purposes.

When the hydrogen absorption of Alloy 2 reaches its limit and the hydrogen release of Alloy 1 is completed during A, J is applied to Pal 1 operation, and Alloys 1 and 2 are
Needless to say, the hydrogen gas produced by I'i is now stored in Alloy 1, and the hydrogen stored in Alloy 2 is dissipated. By repeating such operations, a'li Junmaro Hosei no I can be manufactured. On this occasion,
The first I to be released from Alloy 1 to T4! The IJ gas contains many impurities and is released from the valve S to the outside of the system.

If you want to obtain extremely high hydrogen gas, for example, 99.999% or more, you can use two or more stages of occlusion and release into a hydrogen storage alloy, that is, prepare two or more alloy silks. It is convenient to process the hydrogen gas emitted from the first stage by occluding it in the second stage alloy and then releasing it.

According to the present invention, although it depends on the efficiency of the heat engine, about 30% of the power required for compressing crude hydrogen gas can be supplemented with the energy generated as a result of hydrogen storage.

Various modifications are possible to the present invention. For example, the cold energy of CO + CH4 after heat exchange can be converted into 1 after compression.
] Cold production of hydrogen gas 7. It is also beneficial to use other cold heat sources such as exhaust heat and LNG, and by incorporating and using them, the degree of energy savings can be increased.

[Brief explanation of the drawing]

The drawing is a flow diagram showing one culm of the method for producing pure hydrogen gas of the present invention. Patent applicant Daido Steel Co., Ltd. Agent Patent attorney Sodai Suga

Claims (2)

[Claims] (1) By lowering the temperature of the crude hydrogen gas, impurities in the gas are liquefied, gas and liquid are separated, and the purified hydrogen gas is converted into a hydrogen storage alloy. The process of occluding and then releasing hydrogen gas consists of hydrogen gas of very high purity. The method for producing high-purity hydrogen gas is characterized by converting the fuel into a moving horn and using this power for gas compression. (2) The manufacturing method according to claim 1, which utilizes a hydrogen storage alloy which is emitting hydrogen gas and is therefore absorbing -C heat as a low temperature source for a heat engine.