JPH01126203A - Production of high-purity gaseous hydrogen - Google Patents

Abstract

PURPOSE:To easily and efficiently obtain high-purity gaseous hydrogen by successively introducing the raw gas into an adsorption tower packed with the adsorbent adsorbing the components other than hydrogen and a hydrogen occlusion tower packed with a hydrogen storage alloy, and desorbing the hydrogen. CONSTITUTION:The raw gas 1 (e.g., the steam-reformed gas of methanol) is passed through the adsorption towers 2, 2a, and 2b packed with the adsorbent (e.g., activated alumina and zeolite) adsorbing the components other than hydrogen to adsorb the CO, CO2, etc., other than hydrogen, and gaseous hydrogen is produced. The gaseous hydrogen is then introduced into the hydrogen occlusion towers 6 and 6a packed with a hydrogen storage alloy, occluded in the alloy, and separated from the components other than gaseous hydrogen. The hydrogen occlusion towers 6 and 6a are heated by the hot water at about 50 deg.C from lines 10 and 10a, hence gaseous hydrogen is desorbed, and high-purity gaseous hydrogen is discharged from a delivery line 11.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a method for producing high-purity hydrogen gas from a raw material gas containing hydrogen.

[Prior art] A method for separating hydrogen gas from a hydrogen-containing raw material gas with relatively high purity (approximately 99.9% to 99.999X) is the cryogenic separation method and gas absorption method. Recently, the PSA method (Pressure
Swing Adsorption) is often used.

In this PSA method, as shown in Fig. 2, a raw material gas line 0 is connected to an adsorption tower O1 filled with an adsorbent such as activated carbon or zeolite.
When the raw material gas is flowed from the hydrogen gas line 03, components with high adsorption properties are selectively adsorbed by the adsorbent, and only hydrogen gas with low adsorption properties can be taken out from the hydrogen gas line 03 with the above purity.

In the case of this PSA method, when impurity components are adsorbed by the adsorbent after a certain amount of operation, the adsorption performance deteriorates, so it is necessary to repeatedly regenerate the adsorbent. In order to perform this regeneration, the pressure in the adsorption tower O1 is reduced as much as possible, and as much as possible of high-purity hydrogen gas, that is, high-purity product gas, is sent into the adsorption tower O1 via the purge line 04. Need to purge.

[Problems with the prior art] Therefore, in the conventional PSA method, there is a problem in that a large amount of product hydrogen gas must be used for purging for desorption and regeneration, and the amount is limited to the amount of hydrogen gas in the raw material gas. It extends to more than 30z and productivity is poor.

Furthermore, even if more purge gas is used than the current one, there is almost no effect of increasing purity; if even higher purity is required, it must be purified using activated carbon cooled with liquid nitrogen or purified using a baradium metal membrane. It won't happen. However, in the former case, an extremely low temperature must be maintained, and in the latter case, a high temperature of 300°C to 500°C must be maintained, and both have the problem of being extremely difficult to handle.

The present invention has been proposed in view of the above points, and the present invention has been proposed in view of the above points.
The purpose of this study is to propose a method for producing highly purified hydrogen gas, which cannot be obtained by the SA method, with high efficiency.

[Means for Solving the Problems] The present invention proposes the following method as a means for solving the above problems.

Hydrogen gas is produced by passing the raw material gas through an adsorption tower filled with an adsorbent that adsorbs components other than hydrogen.The hydrogen gas is then guided to a hydrogen storage group filled with a hydrogen storage alloy, where the hydrogen gas is converted into hydrogen. A method of producing high-purity hydrogen gas by occluding it in a storage alloy, separating it from components other than hydrogen gas, and then devolatilizing it.

[Example] Fig. 1 shows a hydrogen gas production apparatus for carrying out the present invention, and the reference numeral 1 indicates a raw material gas feed line serving as a raw material, and 2.2
2.a and 2b are adsorption towers, and activated alumina, activated carbon, and SA type zeolite are filled in this order from the bottom into the adsorption towers 2.2a and 2.2b.

3.3a and 3b are the output lines for the hydrogen gas produced in the adsorption towers 2.2a and 2b, and beyond this are valves 4.4a and 4.
The branch line 5.5a is once joined via line 5.b and then branched off, and the end of this branch line 5.5a is a hydrogen storage alloy (e.g. laN is).
are respectively connected to hydrogen storage groups 6.6a filled with hydrogen storage groups 6.6a.

7.7a is a take-out line for the components separated by the hydrogen storage group 6.6a and the hydrogen gas discharged together with these gases, and the end thereof is connected to the storage tank 8.

9.9a detects the pressure inside the hydrogen storage column 6.6a through a pressure controller attached to each take-out line 7.7a to control the pressure inside the hydrogen storage group 6.6a.

10jOa cools the hydrogen storage group 6.6a during storage,
During devolatilization, a heating line is used to supply water at around 20°C in the case of the embodiment, or hot water at around 50°C.

It is a high-purity hydrogen gas delivery line 12 that sends out high-purity hydrogen gas produced by devolatilization using the hydrogen storage group 6.6a.
．． 12a and 12b are the high purity hydrogen gas delivery lines 11;
This is a purge line that is branched from the adsorption towers 2.2a and 2b via valves 13.13a and 13b.

14 is an auxiliary purge line extending from the storage tank 8 to each adsorption tower 2.2a, 2b.

Next, a method for producing high-purity hydrogen gas according to the present invention using the above-mentioned apparatus will be explained.

From the raw material gas line 1, methanol steam reformed gas 5
N'/H (pressure 6.5 kg/cw"G, temperature 40
°C, component If272.0$, C0,24,0X, Co
4.0! , water vapor saturation) is supplied. This raw material gas is put into either one of the adsorption towers 2.2a and 2b, where it is separated into hydrogen gas, and CO□ and CO remain adsorbed by the adsorbent. The hydrogen gas (purity 99.999$') from which CO, . The unoccluded C01C02 and the hydrogen gas discharged together with these gases are stored in the storage tank 8.

The hydrogen gas stored in the hydrogen storage group 6.6a is 5
It is devolatilized by supplying hot water at 0°C and becomes highly pure (purity 99.
9999X or more) becomes hydrogen gas and is sent out from the high-purity hydrogen gas delivery line 11 to the hydrogen gas storage facility or the consumption side.

To purge the adsorption towers 2.2a and 2b, first, the hydrogen gas in the storage tank 8 is used to purge into the target adsorption tower 2 or 2a or 2b from the auxiliary purge line 14, and then the hydrogen storage group 6.6a is purged. The purge line 12.12a is filled with high-purity hydrogen gas obtained by devolatilizing the hydrogen gas occluded in
Purge from +2b.

Table 1 shows the analysis results of hydrogen gas discharged from the adsorption towers 2.2a and 2b and the hydrogen storage group 6.6a.

Table 1 Hydrogen gas analysis results (unit: PPM) Analysis method 1, CO1CO2, CH4, total hydrocarbon dihydrogen gas chromatography with flame ionization detector 2, N2: Thermal conductivity Gas chromatography with detector 3.0 = Yellow resilin type [Effects of the present invention] As described above, the present invention combines the known hydrogen gas production method (PSA method) with a method of separating hydrogen using a hydrogen storage alloy, thereby producing high-purity hydrogen gas. (99,999
9X or more).

Further, this manufacturing method does not require low or high temperatures as in the conventional methods and can be handled at room temperature, so handling is easy.

Next, according to the method of the present invention, hydrogen gas that has been stored in a storage tank without being occluded is first used as a purge gas for the adsorption tower, and then regenerated using high-purity hydrogen gas as a finish, so the regeneration rate is The amount of high-purity hydrogen gas consumed for purging is also low, and high efficiency can be achieved. Incidentally, the hydrogen gas recovery rate when implementing the present invention can be kept at about 70%, which is the same level as the recovery rate in the PSA method.

[Brief explanation of the drawing]

Fig. 1 is an explanatory diagram of a hydrogen gas production apparatus for carrying out the present invention, and Fig. 2 is an explanatory diagram of a hydrogen gas production apparatus for carrying out the present invention, and Fig. 2 is a step for transferring hydrogen gas remaining in the tower after the adsorption step to another tower, omitting the pipe and inlet. P.S.A.
It is an explanatory diagram of the law. 1... Raw material gas feed lines 2.2a, 2b... Adsorption tower 6.6a... Hydrogen storage group 11... High purity hydrogen gas delivery line 12. 12a, 12b...purge line 14...
Auxiliary purge line #'lI'P%, j1 1, ζ71 2zu;

Claims (1)

[Claims] Hydrogen gas is produced by passing the raw material gas through an adsorption tower filled with an adsorbent that adsorbs components other than hydrogen.The hydrogen gas is then led to a hydrogen storage tower filled with a hydrogen storage alloy, where the hydrogen gas is converted into hydrogen. A method of producing high-purity hydrogen gas by occluding it in a storage alloy, separating it from components other than hydrogen gas, and then devolatilizing it.