阅读说明：本技术 由含氢气体制备高纯氢气的装置及方法 (Device and method for preparing high-purity hydrogen from hydrogen-containing gas ) 是由 刘聪敏 李轩 何广利 杨康 李先明 于 2018-06-04 设计创作，主要内容包括：本发明涉及高纯氢气制备领域,具体涉及一种由含氢气体制备高纯氢气的装置及方法。该装置包括：含氢气体供给单元(1)、变压吸附单元(2)、气体缓冲单元(3)、充气单元(4)、氢气吸收单元(5)、用于将充气单元(4)中未被吸收的气体输送至含氢气体供给单元的气体回流管线(6)。该方法包括：变压吸附单元吸附、充气单元4充气、氢气吸收单元吸收、解析产品气、其中,所述含氢气体含有所述未被吸附的气体。本发明提供的装置和方法具有以下优点：(1)产品气的纯度高,可以得到纯度为99.999％的氢气；(2)工艺流程简单,操作方便,无需复杂的预处理,可以处理多种复杂的气源。(the invention relates to the field of high-purity hydrogen preparation, in particular to a device and a method for preparing high-purity hydrogen from hydrogen-containing gas. The device includes: the hydrogen-containing gas absorption system comprises a hydrogen-containing gas supply unit (1), a pressure swing adsorption unit (2), a gas buffer unit (3), an aeration unit (4), a hydrogen absorption unit (5) and a gas return line (6) for conveying unabsorbed gas in the aeration unit (4) to the hydrogen-containing gas supply unit. The method comprises the following steps: the pressure swing adsorption unit adsorbs, the aeration unit 4 aerates, the hydrogen absorption unit absorbs and analyzes the product gas, wherein the hydrogen-containing gas contains the gas which is not adsorbed. The device and the method provided by the invention have the following advantages: (1) the purity of the product gas is high, and hydrogen with the purity of 99.999 percent can be obtained; (2) the process flow is simple, the operation is convenient, complex pretreatment is not needed, and various complex gas sources can be treated.)

1. an apparatus for producing high purity hydrogen from a hydrogen-containing gas, the apparatus comprising, in order from the flow direction:

a hydrogen-containing gas supply unit (1);

The pressure swing adsorption unit (2) is used for carrying out pressure swing adsorption on heavy component gas relative to hydrogen in the hydrogen-containing gas from the hydrogen-containing gas supply unit (1) to obtain hydrogen-containing intermediate product gas;

The gas buffer unit (3) is used for temporarily storing the hydrogen-containing intermediate product gas from the pressure swing adsorption unit (2);

An aeration unit (4) for receiving the hydrogen-containing intermediate product gas from the gas buffer unit (3) and supplying the received hydrogen-containing intermediate product gas to the hydrogen absorption unit (5);

a hydrogen absorption unit (5) for absorbing hydrogen in the hydrogen-containing intermediate product gas from the aeration unit (4);

And a gas return line (6) for conveying the gas not absorbed in the gas-charging unit (4) to the hydrogen-containing gas supply unit (1) and mixing the gas with the gas contained therein as the hydrogen-containing gas.

2. The apparatus of claim 1, wherein the pressure swing adsorption unit (2) comprises at least 2 pressure swing adsorption columns connected in parallel, the aeration unit (4) comprises at least 2 aeration columns connected in parallel, and the hydrogen absorption unit (5) comprises at least 2 hydrogen absorption columns connected in parallel.

3. the device according to claim 1 or 2, wherein the gas buffer unit (3) comprises a high pressure gas buffer tank (31) and a low pressure gas buffer tank (32);

Wherein the high-pressure gas buffer tank (31) temporarily stores part of the obtained hydrogen-containing intermediate product gas in the process of adsorbing the recombinant gas; and the low-pressure gas buffer tank (32) temporarily stores part of residual hydrogen-containing intermediate product gas after the adsorption of the heavy component gas is finished.

4. An arrangement according to any one of claims 1-3, wherein a booster pump 7 is also arranged on the gas return line (6).

5. a method for producing high purity hydrogen gas from a hydrogen-containing gas, the method comprising:

(1) adsorption by the pressure swing adsorption unit (2):

Adsorbing heavy component gas relative to hydrogen in the hydrogen-containing gas in a pressure swing adsorption unit (2) under the adsorption pressure of the heavy component gas relative to the hydrogen to obtain hydrogen-containing intermediate product gas, and injecting part of the hydrogen-containing intermediate product gas into a gas buffer unit (3);

(2) The inflation unit (4) inflates:

Injecting part of the hydrogen-containing intermediate product gas in the gas buffer unit (3) into an aeration unit (4) to aerate the aeration unit (4);

(3) The hydrogen absorption unit (5) absorbs:

Contacting at least part of the hydrogen-containing intermediate product gas in the gas charging unit (4) with a hydrogen storage alloy in a hydrogen absorption unit (5) to absorb hydrogen in the hydrogen-containing intermediate product gas;

(4) resolving product gas:

under the analysis condition, analyzing the hydrogen absorbed in the hydrogen absorption unit (5) to obtain a product gas;

wherein the hydrogen-containing gas contains a gas not absorbed by the hydrogen absorption unit (5).

6. A method according to claim 5, wherein the gas buffer unit (3) comprises a high pressure gas buffer tank (31) and a low pressure gas buffer tank (32);

(1) Adsorption by the pressure swing adsorption unit (2):

adsorbing heavy component gas relative to hydrogen in the hydrogen-containing gas in a pressure swing adsorption unit (2) under the adsorption pressure of the heavy component gas relative to the hydrogen, and injecting part of the obtained hydrogen-containing intermediate product gas into a high-pressure gas buffer unit (31) in the adsorption process;

(2) pressure reduction of the pressure swing adsorption unit (2):

after adsorption is finished, injecting at least part of hydrogen-containing intermediate product gas remained in the pressure swing adsorption unit (2) into a low-pressure gas buffer unit (32) so as to reduce the pressure of the pressure swing adsorption unit (2);

(3) The inflation unit (4) inflates:

Injecting part of the hydrogen-containing intermediate product gas in the high-pressure gas buffer tank (31) into an aeration unit (4) to aerate the aeration unit (4);

(4) the hydrogen absorption unit (5) absorbs:

contacting at least part of the hydrogen-containing intermediate product gas in the gas charging unit (4) with a hydrogen storage alloy in a hydrogen absorption unit (5) to absorb hydrogen in the hydrogen-containing intermediate product gas;

(5) And (3) reverse purging and regenerating of the inflating unit (4):

after the hydrogen absorption is finished, injecting part of hydrogen-containing intermediate product gas in the low-pressure gas buffer tank (32) into an inflation unit (4) so as to purge and regenerate the inflation unit (4) to obtain purge and regenerated gas;

(6) Resolving product gas:

under the analysis condition, analyzing the hydrogen absorbed in the hydrogen absorption unit (5) to obtain a product gas;

wherein the hydrogen-containing gas comprises the purge regeneration gas;

Preferably, the method further comprises:

reverse emptying: discharging the adsorbed heavy components in the pressure swing adsorption unit (2) after pressure reduction, and reversely emptying the pressure swing adsorption unit (2);

Purging and regenerating: providing a hydrogen-containing intermediate product gas to a reverse vented pressure swing adsorption unit (2) to purge and regenerate the pressure swing adsorption unit (2);

boosting pressure: reintroducing the hydrogen-containing intermediate product gas into the pressure swing adsorption unit (2) after purging and regeneration so as to boost the pressure of the pressure swing adsorption unit (2);

final pressure boosting: introducing a hydrogen-containing intermediate product gas into the pressure swing adsorption unit (2) after pressure boosting for final pressure boosting so as to enable the pressure swing adsorption unit (2) to reach the adsorption pressure.

7. the method according to any one of claims 5-6, wherein the pressure swing adsorption unit (2) comprises at least 2 pressure swing adsorption columns in parallel, the aeration unit (4) comprises at least 2 aeration columns in parallel, and the hydrogen absorption unit (5) comprises at least 2 hydrogen absorption columns in parallel;

Wherein the working time sequence of the pressure swing adsorption unit (2), the aeration unit (4) and the hydrogen absorption unit (5) is arranged to continuously prepare high-purity hydrogen from hydrogen-containing gas.

8. The method of claim 6, wherein the pressure swing adsorption unit (2) comprises 4 pressure swing adsorption columns a-1, a-2, a-3, and a-4 in parallel, the aeration unit (4) comprises 2 aeration columns B-1 and B-2 in parallel, the hydrogen absorption unit (5) comprises 2 hydrogen absorption columns C-1 and C-2 in parallel; the process operates according to the sequence in the table below;

wherein the content of the first and second substances,

A is adsorption;

EQ1 is used for providing hydrogen-containing intermediate product gas for the adsorption tower which needs secondary pressure equalization rising for the first time of external pressure equalization rising;

PP is used for forward depressurization and providing hydrogen-containing intermediate product gas for the adsorption tower needing purging and regeneration;

EQ2 is used for two times of external pressure drop and providing hydrogen-containing intermediate product gas for the adsorption tower which needs one time of pressure rise;

The BD is reversely emptied, and the adsorbed heavy component is desorbed and released;

PG is used for purging and regenerating, and hydrogen-containing intermediate product gas is provided by an adsorption tower which needs forward pressure reduction at the same time;

EQ 1' is a primary pressure equalization rise, which is completed by providing hydrogen-containing intermediate product gas for the adsorption tower needing secondary external pressure equalization;

EQ 2' is used for secondary pressure equalization rise and is completed by providing hydrogen-containing intermediate product gas for an adsorption tower which needs one external pressure equalization drop;

RE is final pressure rise and is completed by providing intermediate product gas containing hydrogen by an adsorption tower which performs adsorption simultaneously;

GF is gas filled and is finished by supplying hydrogen-containing intermediate product gas by a high-pressure gas buffer tank (31);

PF' is bleed gas, provide the intermediate product gas containing hydrogen to needing to receive the intermediate product gas containing hydrogen to carry on the hydrogen absorption tower at the same time;

PF is absorption and is completed by providing hydrogen-containing intermediate product gas by an air charging tower which is simultaneously deflated;

RG is reverse purging regeneration, and is completed by supplying intermediate product gas containing hydrogen from a low-pressure gas buffer tank (32);

P is the analysis product gas.

9. the method according to any one of claims 5 to 8, wherein the adsorption pressure of the heavy component gas with respect to hydrogen is 0.15 to 5 MPa;

Preferably, the adsorbent in the pressure swing adsorption unit (1) is selected from activated carbon, molecular sieve, silica gel, carbon molecular sieve, activated alumina and various modified adsorbents.

10. the method according to any one of claims 5 to 9, wherein the hydrogen storage alloy is selected from the group consisting of a rare earth-based hydrogen storage alloy, an AB-type titanium-based hydrogen storage alloy, a vanadium-based solid solution-type hydrogen storage alloy, a magnesium-based hydrogen storage alloy, and an AB 2-type Laves phase titanium-based hydrogen storage alloy.

Technical Field

The invention relates to the field of high-purity hydrogen preparation, in particular to a device and a method for preparing high-purity hydrogen from hydrogen-containing gas.

Background

Hydrogen is an important chemical raw material, industrial protective gas and clean fuel, for example, hydrogen is one of the main raw materials in the synthetic ammonia industry, and hydrogen is widely used for the desulfurization of naphtha, gas oil, fuel oil and heavy oil and the hydrofining of unsaturated hydrocarbon and the like in the oil refining industry to improve the quality of oil products; in the electronics and metallurgical industry, hydrogen is mainly used as a reducing gas; in fuel cell automobile houses, hydrogen is an important fuel. With the increasingly strict environmental regulations and the good combustion performance of hydrogen, the market in the future has a huge potential demand for hydrogen. The purity of hydrogen is highly desirable in industrial processes, such as the electronics industry where purity levels of greater than 99.999% are required, and in some cases even higher. Therefore, the hydrogen-containing raw gas needs to be separated and purified to meet different production requirements. Currently developed hydrogen separation methods include pressure swing adsorption, cryogenic methods, membrane separation, and metal hydride methods.

₂1. The basic principle of Pressure Swing Adsorption (PSA) separation technology is to utilize the Adsorption characteristic difference of different gas components on a solid material and the characteristic that the Adsorption quantity changes with the Pressure, and realize the separation or purification of gas by periodically changing the Pressure of an Adsorption bed layer.

₂2. A cryogenic separation method, called cryogenic rectification method, features that the different relative volatilities of raw materials are used to make the raw materials pass through gas turbine expansion for refrigeration, the components in dry gas are condensed at low temp. according to the technological requirements, and the various hydrocarbons are separated one by one according to their boiling points by rectification method.

3. Membrane separation method: the membrane separation is a new high-efficiency separation technology, which uses a membrane as a selective barrier layer, a certain amount of energy difference exists on two sides of the membrane as power, certain components are allowed to permeate and other components in a mixture are retained, and the mobility of each component permeating the membrane is different, so that the separation purpose is achieved. The process flow of the membrane separation is very simple, the operation is convenient, and the investment is low; however, the film-forming technique (such as uniformity, stability, aging resistance, heat resistance, etc. of the film) is required to be continuously improved, the service life of the film is short, and the feed gas is required to be free of solids and oil droplets to prevent damage to the film module. The purity of the product is not high (99%), but the pressure of the required raw material gas is high, and the purity of the product hydrogen can reach 99% by adopting a two-stage membrane separator.

4. The metal hydride purification method is characterized in that the hydrogen storage material is used for absorbing hydrogen at low temperature and releasing hydrogen at high temperature to purify hydrogen, the purity of the product hydrogen is very high, but the requirements on the types of impurity gases except the hydrogen in the raw material gas are strict, the impurity gases such as H ₂ O, H ₂ S, O ₂ and the like can cause poisoning effect on the metal hydride, the hydrogen storage metal material can generate brittle fracture and pulverization phenomena after being recycled for multiple times, and the production scale is not large, so the method is not suitable for large-scale separation and purification of crude hydrogen and hydrogen-containing tail gas.

therefore, it is important to develop a method that can achieve both recovery rate and hydrogen purity.

disclosure of Invention

The invention aims to overcome the problems in the prior art and provide a device and a method for preparing high-purity hydrogen from hydrogen-containing gas, wherein the concentration of the hydrogen obtained by the device and the method is more than 99.999 percent, the recovery rate of the hydrogen can reach more than 85 percent, and various complex gas sources can be treated.

In order to achieve the above object, an aspect of the present invention provides an apparatus for producing high-purity hydrogen gas from a hydrogen-containing gas, the apparatus comprising:

A hydrogen-containing gas supply unit;

The pressure swing adsorption unit is used for carrying out pressure swing adsorption on heavy component gas relative to the hydrogen in the hydrogen-containing gas from the hydrogen-containing gas supply unit to obtain hydrogen-containing intermediate product gas;

The gas buffer unit is used for temporarily storing the hydrogen-containing intermediate product gas from the pressure swing adsorption unit;

An aeration unit for receiving the hydrogen-containing intermediate product gas from the gas buffer unit and supplying the received hydrogen-containing intermediate product gas to the hydrogen absorption unit;

The hydrogen absorption unit is used for absorbing hydrogen in the hydrogen-containing intermediate product gas from the aeration unit;

And a gas return line for transferring the gas not absorbed in the gas filling unit to the hydrogen-containing gas supply unit (1) and mixing it with the gas contained therein as the hydrogen-containing gas.

In a second aspect, the present invention provides a method for producing high purity hydrogen gas from a hydrogen-containing gas, the method comprising:

(1) adsorption by a pressure swing adsorption unit:

Adsorbing heavy component gas relative to hydrogen in the hydrogen-containing gas in a pressure swing adsorption unit under the adsorption pressure of the heavy component gas relative to the hydrogen to obtain hydrogen-containing intermediate product gas, and injecting part of the hydrogen-containing intermediate product gas into a gas buffer unit;

(2) The inflation unit is inflated:

Injecting part of the hydrogen-containing intermediate product gas in the gas buffer unit into an inflating unit to inflate the inflating unit;

(3) Absorption by a hydrogen absorption unit:

contacting at least part of the hydrogen-containing intermediate product gas in the gas charging unit with a hydrogen storage alloy in a hydrogen absorption unit to absorb hydrogen in the hydrogen-containing intermediate product gas;

(4) resolving product gas:

Under the analysis condition, analyzing the hydrogen absorbed in the hydrogen absorption unit to obtain a product gas;

Wherein the hydrogen-containing gas contains a gas not absorbed by the hydrogen absorption unit.

The device and the method provided by the invention have the following advantages: (1) the purity of the product gas is high, the hydrogen with the purity of 99.999 percent can be obtained, and the recovery rate of the hydrogen can reach more than 85 percent; (2) the process flow is simple, the operation is convenient, complex pretreatment is not needed, and various complex gas sources can be treated; (3) the hydrogen recovery rate is high.

drawings

fig. 1 shows an apparatus for producing high-purity hydrogen gas from a hydrogen-containing gas according to an embodiment of the present invention.

Description of the reference numerals

1 hydrogen-containing gas supply unit 2 pressure swing adsorption unit 3 gas buffer unit

4 gas charging unit 5 hydrogen absorption unit 6 gas return line

7 booster pump 31 high-pressure gas buffer tank 32 low-pressure gas buffer tank

A-1, A-2, A-3 and A-4 are adsorption towers B-1 and B-2 is an aeration tower

C-1, C-2 are metal hydride purifying column

a-1-1, A-1-2, A-1-3, A-1-4, A-1-5, A-2-1, A-2-2, A-2-3, A-2-4, A-2-5, A-3-1, A-3-2, A-3-3, A-3-4, A-3-5, A-4-1, A-4-2, A-4-3, A-4-4, A-4-5, B-1-1, B-1-2, B-1-3, B-1-4, B-2-1, B-2-2, B-2-3, B-2-4, C-1-1, C-1-2, C-2-1, C-2-2, D-2-1 and D-2-2 are program control valves.

Detailed Description

the endpoints of the ranges and any values disclosed herein are not limited to the precise range or value, and such ranges or values should be understood to encompass values close to those ranges or values. For ranges of values, between the endpoints of each of the ranges and the individual points, and between the individual points may be combined with each other to give one or more new ranges of values, and these ranges of values should be considered as specifically disclosed herein.

according to a first aspect of the present invention, there is provided an apparatus for producing high purity hydrogen gas from a hydrogen-containing gas, the apparatus comprising:

a hydrogen-containing gas supply unit 1;

the pressure swing adsorption unit 2 is used for carrying out pressure swing adsorption on heavy component gas relative to hydrogen in the hydrogen-containing gas from the hydrogen-containing gas supply unit 1 to obtain hydrogen-containing intermediate product gas;

the gas buffer unit 3 is used for temporarily storing the hydrogen-containing intermediate product gas from the pressure swing adsorption unit 2;

an aeration unit 4 for receiving the hydrogen-containing intermediate product gas from the gas buffer unit 3 and supplying the received hydrogen-containing intermediate product gas to the hydrogen absorption unit 5;

A hydrogen absorption unit 5 for absorbing hydrogen in the hydrogen-containing intermediate product gas from the aeration unit 4;

and a gas return line 6 for transferring the gas not absorbed in the gas-filling unit 4 to the hydrogen-containing gas supply unit 1 and mixing it with the gas contained therein as the hydrogen-containing gas.

in the present invention, the hydrogen-containing gas (raw material gas) may be any hydrogen-containing gas, and is generally a hydrogen-containing raw material gas generally used for producing high-purity hydrogen. For example, the hydrogen-containing gas (raw gas) can be various industrial exhaust tail gases containing hydrogen with the concentration of 20-85 vol%, such as methanol purge gas, coke oven gas tail gas, chlor-alkali industry hydrogen-containing tail gas, and the like.

in the present invention, the pressure swing adsorption unit 2 preferably comprises at least 2 pressure swing adsorption towers connected in parallel, and in this preferred case, continuous separation of the hydrogen-containing gas can be realized, that is, through reasonable timing arrangement, when 1 or more pressure swing adsorption towers are regenerated, the other pressure swing adsorption towers can be in working state, thereby realizing continuous separation of the hydrogen-containing gas and greatly shortening the separation time.

in addition, the pressure swing adsorption column is packed with a packing (adsorbent) that can specifically adsorb heavy component gases relative to hydrogen in hydrogen-containing gases. The type of the filler may be specifically selected depending on the composition of the raw material gas, and may be one or more, and may be selected from, for example, activated carbon, molecular sieves, silica gel, carbon molecular sieves, activated alumina, zeolite, and various modified adsorbents. For example, when the raw material gas is a mixed gas of hydrogen and carbon dioxide, the filler may be activated carbon; when the raw material gas is a mixed gas of hydrogen and nitrogen or argon, the filler can be activated carbon and/or 5A molecular sieve. The invention is not further illustrated here.

The adsorption pressure of the heavy component may be specifically adjusted according to the composition of the raw material gas, and preferably, the adsorption pressure is 0.15 to 5 MPa. For example, when the feed gas is methanol purge gas tail gas, the adsorption pressure may be 1.0-3.0 MPa; when the raw material gas is coke oven gas tail gas, the adsorption pressure can be 0.15-1.0 MPa. The invention is not further illustrated here.

In the present invention, the method for providing the adsorption pressure in the pressure swing adsorption unit 2 is not particularly limited, and for example, the adsorption pressure may be provided by reversely feeding a product gas into the pressure swing adsorption unit 2, the adsorption pressure may be provided by feeding a hydrogen-containing gas (raw material gas) into the pressure swing adsorption unit 2, the adsorption pressure may be provided by feeding a hydrogen-containing intermediate product gas into the pressure swing adsorption unit 2, or a combination of these types of gases. The invention preferably uses the hydrogen-containing intermediate product gas to provide the adsorption pressure, and under the preferred condition, the recovery rate of the hydrogen can be effectively improved.

according to a preferred embodiment of the present invention, the gas buffer unit 3 includes a high-pressure gas buffer tank 31 and a low-pressure gas buffer tank 32. In the process of performing pressure swing adsorption on heavy component gas relative to hydrogen in hydrogen-containing gas by the pressure swing adsorption unit 2, unadsorbed light components, that is, hydrogen-containing intermediate product gas can be temporarily stored in the high-pressure gas buffer tank 31, on one hand, the high-pressure gas buffer tank 31 can temporarily store excessive intermediate product gas, so that resource waste is not caused, and on the other hand, the intermediate product gas can be provided for the hydrogen absorption unit 2 by stable gas flow, so that hydrogen is absorbed more sufficiently. After the heavy component gas is subjected to one round of absorption, since a large amount of intermediate product gas containing hydrogen remains in the pressure swing adsorption unit 2, in order to increase the recovery rate of hydrogen, it is preferable to send part of the intermediate product gas containing hydrogen remaining in the pressure swing adsorption unit 2 to the low-pressure gas buffer tank 32 for standby.

In the present invention, the aeration unit 4 is arranged to further provide the hydrogen-containing intermediate gas to the hydrogen absorption unit 5 with a stable gas flow for hydrogen absorption, and on the other hand, the purity of the hydrogen after desorption can be further improved by discharging unabsorbed impurity gas after the hydrogen absorption is finished. According to a preferred embodiment of the present invention, the discharged impurity gas not absorbed in the aeration unit 4 may be flushed by the hydrogen-containing intermediate product gas stored from the low-pressure gas buffer tank 32, and the flushed gas is returned to the hydrogen-containing gas supply unit 1 through the gas return line 6 and purified again as part of the hydrogen-containing gas. On the one hand, the produced intermediate product gas which cannot be utilized is effectively utilized, on the other hand, the regeneration of the aeration unit 4 is also completed, and on the other hand, the recovery rate of the hydrogen can also be improved.

Wherein, in order to be able to efficiently recover the unabsorbed gas and to serve as part of the hydrogen-containing gas, a booster pump 7 is further provided on the gas return line 6 to recover the obtained purge gas to the hydrogen-containing gas supply unit 1.

In the present invention, the hydrogen absorption unit 5 preferably comprises at least 2 hydrogen absorption towers connected in parallel, and in this preferred case, continuous separation of hydrogen-containing gas can be achieved, that is, through reasonable timing arrangement, when 1 or several hydrogen absorption towers among them perform impurity gas evacuation and hydrogen desorption, the other hydrogen absorption towers can be in a working state, thereby achieving continuous separation of hydrogen-containing gas and greatly shortening separation time.

In addition, the hydrogen absorption tower is filled with hydrogen storage alloy which can react with hydrogen-containing gas to form metal hydride. The hydrogen storage alloy can be various conventional hydrogen storage alloys for reacting with hydrogen, and at least one of rare earth hydrogen storage alloy, AB type titanium-based hydrogen storage alloy, vanadium-based solid solution type hydrogen storage alloy, magnesium-based hydrogen storage alloy and AB2 type Laves phase titanium-based hydrogen storage alloy is preferably selected in the invention.

the conditions for the reaction of hydrogen with the hydrogen storage alloy may be selected conventionally, and preferably, in order to achieve the absorption reaction of hydrogen with maximum efficiency and to remove other impurity gases, the hydrogen absorption is carried out at a plateau pressure (0.5 to 5MPa) or more at a specific working temperature (e.g., 0 to 250 ℃) for hydrogen storage of the selected hydrogen storage alloy. The specific operating temperature and plateau pressure for each hydrogen storage alloy are well known to those skilled in the art and will not be described in detail herein.

In the present invention, the analysis of the hydrogen in the hydrogen absorption unit 5 may include room temperature (5-40 ℃) reduced pressure analysis, elevated temperature and reduced pressure analysis, and vacuum analysis, and the analysis of the hydrogen may be performed under the plateau pressure at the specific working temperature of the selected hydrogen storage alloy.

according to a second aspect of the present invention, there is provided a method for producing high purity hydrogen gas from a hydrogen-containing gas, the method comprising:

(1) The pressure swing adsorption unit 2 is used for adsorption:

Absorbing heavy component gas relative to hydrogen in the hydrogen-containing gas in a pressure swing adsorption unit 2 under the adsorption pressure of the heavy component gas relative to the hydrogen to obtain hydrogen-containing intermediate product gas, and injecting part of the hydrogen-containing intermediate product gas into a gas buffer unit 3;

(2) The inflation unit 4 inflates:

injecting part of the hydrogen-containing intermediate product gas in the gas buffer unit 3 into an inflating unit 4 to inflate the inflating unit 4;

(3) The hydrogen absorption unit 5 absorbs:

contacting at least part of the hydrogen-containing intermediate product gas in the gas charging unit 4 with a hydrogen storage alloy in a hydrogen absorption unit 5 to absorb hydrogen in the hydrogen-containing intermediate product gas;

(4) resolving product gas:

Under the analysis condition, analyzing the hydrogen absorbed in the hydrogen absorption unit 5 to obtain a product gas;

wherein the hydrogen-containing gas contains a gas not absorbed by the hydrogen absorption unit 5.

The process apparatus, process conditions and preferred embodiments for producing high purity hydrogen from hydrogen-containing gas have been described in detail above, and the present invention will not be described herein again in order to avoid unnecessary repetition.

In the present invention, when the gas buffer unit 3 includes a high-pressure gas buffer tank 31 and a low-pressure gas buffer tank 32, the method of the present invention includes:

(1) the pressure swing adsorption unit 2 is used for adsorption:

adsorbing heavy component gas relative to hydrogen in the hydrogen-containing gas in a pressure swing adsorption unit 2 under the adsorption pressure of the heavy component gas relative to hydrogen, and injecting part of the obtained hydrogen-containing intermediate product gas into a high-pressure gas buffer unit 31 in the adsorption process;

(2) Pressure reduction of the pressure swing adsorption unit 2:

After adsorption is finished, injecting at least part of hydrogen-containing intermediate product gas remained in the pressure swing adsorption unit 2 into a low-pressure gas buffer unit 32 so as to reduce the pressure of the pressure swing adsorption unit 2;

(3) The inflation unit 4 inflates:

Injecting part of the hydrogen-containing intermediate product gas in the high-pressure gas buffer tank 31 into the aeration unit 4 to aerate the aeration unit 4;

(4) The hydrogen absorption unit 5 absorbs:

contacting at least part of the hydrogen-containing intermediate product gas in the gas charging unit 4 with a hydrogen storage alloy in a hydrogen absorption unit 5 to absorb hydrogen in the hydrogen-containing intermediate product gas;

(5) And (3) reverse purging and regenerating of the aeration unit 4:

after the hydrogen absorption is finished, injecting part of hydrogen-containing intermediate product gas in the low-pressure gas buffer tank 32 into the inflation unit 4 to perform purging regeneration on the inflation unit 4 to obtain purging regeneration gas;

(6) Resolving product gas:

Under the analysis condition, analyzing the hydrogen absorbed in the hydrogen absorption unit 5 to obtain a product gas;

wherein the hydrogen-containing gas contains the purge regeneration gas.

as described above, although a part of the hydrogen-containing intermediate product gas remaining in the pressure swing adsorption unit 2 has been sent to the low-pressure gas buffer tank 32, in order to improve the recovery rate of hydrogen, it is preferable that the pressure swing adsorption unit 2 after completion of adsorption be depressurized by the following procedure: a: after adsorption is finished, firstly, equalizing the pressure of the residual intermediate product gas to another storage unit; b: then the mixture is homogenized to the low-pressure gas buffer tank 32; c: and finally, equalizing the pressure to another storage unit. When the pressure swing adsorption unit comprises more than 2 pressure swing adsorption columns, the additional storage unit may be an additional pressure swing adsorption column. After the depressurization is completed, the pressure swing adsorption unit 2 may be vented by opening a programmable valve between the pressure swing adsorption unit 2 and the waste gas line (for the desorption of the heavies, reference may be made to the regeneration of the pressure swing adsorption unit in pressure swing adsorption known in the art, for example, by using a method of pressure reduction (evacuation) or atmospheric desorption) to accomplish the reverse venting of the pressure swing adsorption unit 2.

According to the invention, in order to complete the next cycle of adsorption, the method also comprises the steps of purging, regenerating, boosting and final pressure of the pressure swing adsorption unit 2 which is reversely emptied. Wherein, the purging regeneration preferably uses the obtained hydrogen-containing intermediate product gas, and when the pressure swing adsorption unit 2 comprises more than 2 pressure swing adsorption towers, the purging gas comes from another pressure swing adsorption tower. After the regeneration is waited to sweep, can adopt the intermediate product gas to all step up to the pressure swing adsorption unit 2's that steps up, work as pressure swing adsorption unit 2 includes the pressure swing adsorption tower more than 2, can adopt the intermediate product gas that is releasing to the pressure swing adsorption tower of external pressure equalizing to all step up. After the pressure equalization, the product gas may be reversely introduced into the pressure swing adsorption unit 2 to provide the adsorption pressure, the hydrogen-containing gas (raw gas) may be introduced into the pressure swing adsorption unit 2 to provide the adsorption pressure, the hydrogen-containing intermediate product gas may be introduced into the pressure swing adsorption unit 2 to provide the adsorption pressure, or a combination of these types of gases may be provided. In the invention, preferably, a hydrogen-containing intermediate product gas is introduced into the pressure swing adsorption unit 2 to provide the adsorption pressure, and when the pressure swing adsorption unit 2 comprises more than 2 pressure swing adsorption towers, the intermediate product gas providing the adsorption pressure can be an intermediate product gas generated in the adsorption process of another adsorption tower.

according to the invention, when the pressure swing adsorption unit 2 comprises at least 2 pressure swing adsorption towers connected in parallel, the aeration unit 4 comprises at least 2 aeration towers connected in parallel, and the hydrogen absorption unit 5 comprises at least 2 hydrogen absorption towers connected in parallel, the whole system can be always in a continuous working state by reasonably arranging the working time sequence of each tower, so that the production efficiency is greatly improved. The mode of keeping the system continuously running is illustrated by taking the example that the pressure swing adsorption unit 2 comprises 4 pressure swing adsorption towers A-1, A-2, A-3 and A-4 connected in parallel, the aeration unit 4 comprises 2 aeration towers B-1 and B-2 connected in parallel, and the hydrogen absorption unit 5 comprises 2 hydrogen absorption towers C-1 and C-2 connected in parallel, and the specific working time sequence of each tower is shown in Table 1.

wherein A is adsorption; EQ1 is used for providing hydrogen-containing intermediate product gas for the adsorption tower which needs secondary pressure equalization rising for the first time of external pressure equalization rising;

PP is used for forward depressurization and providing hydrogen-containing intermediate product gas for the adsorption tower needing purging and regeneration; EQ2 is used for two times of external pressure drop and providing hydrogen-containing intermediate product gas for the adsorption tower which needs one time of pressure rise; the BD is reversely emptied, and the adsorbed heavy component is desorbed and released; PG is used for purging and regenerating, and hydrogen-containing intermediate product gas is provided by an adsorption tower which needs forward pressure reduction at the same time; EQ 1' is a primary pressure equalization rise, which is completed by providing hydrogen-containing intermediate product gas for the adsorption tower needing secondary external pressure equalization; EQ 2' is used for secondary pressure equalization rise and is completed by providing hydrogen-containing intermediate product gas for an adsorption tower which needs one external pressure equalization drop; RE is final pressure rise and is completed by providing intermediate product gas containing hydrogen by an adsorption tower which performs adsorption simultaneously; GF is gas filled and is finished by supplying hydrogen-containing intermediate product gas by a high-pressure gas buffer tank (31); PF' is bleed gas, provide the intermediate product gas containing hydrogen to needing to receive the intermediate product gas containing hydrogen to carry on the hydrogen absorption tower at the same time; PF is absorption and is completed by providing hydrogen-containing intermediate product gas by an air charging tower which is simultaneously deflated; RG is reverse purging regeneration, and is completed by supplying intermediate product gas containing hydrogen from a low-pressure gas buffer tank (32); p is the analysis product gas.

in the present invention, the flow of gas streams between the units can be controlled by means of programmable valves arranged on the pipelines, for example, as described in connection with FIG. 1 (when the pressure swing adsorption unit 2 comprises at least 2 pressure swing adsorption columns connected in parallel, the aeration unit 4 comprises at least 2 aeration columns connected in parallel, and the hydrogen absorption unit 5 comprises at least 2 hydrogen absorption columns connected in parallel),

for the A-1 column:

(1) Adsorption: and opening the program control valves A-1-1 and A-1-5, feeding the feed gas into the adsorption tower A-1 through the valve A-1-1, adsorbing heavy component substances in the feed gas by an adsorbent under adsorption pressure, and feeding unadsorbed light components into the high-pressure gas buffer tank 31 through the valve A-1-5. When the adsorption front of heavy component material reaches a certain position of adsorption tower, closing valves A-1-1 and A-1-5, stopping feeding raw material gas into adsorption tower A-1, and maintaining the pressure in the tower during adsorption.

(2) Once external average pressure drop: and after the adsorption step of the A-1 tower is stopped, opening the range control valves A-1-3 and A-3-3 to ensure that the outlet end of the A tower is communicated with the outlet end of the A-3 tower which just finishes the pressure equalization rising step, and allowing the gas in the dead space in the A-1 tower to flow into the A-3 tower from the outlet end of the A-1 tower through the A-1-3 and A-3-3 valves. At the end of this step, the column pressures A-1 and A-3 are essentially in equilibrium.

(3) forward depressurization to provide purge gas: after the step of once external average pressure drop of the A-1 tower is stopped, closing the program control valves A-1-3 and A-3-3, and opening the program control valves A-1-4, A-4-2 and D-2-1, so that the outlet end of the A-1 tower is communicated with the outlet end of the adsorption tower A-4 to be communicated with the low-pressure buffer tank D-2, part of gas flows into the A-4 tower from the outlet end of the A-1 tower through the valves A-1-4 and A-4-4 from the outlet end of the A-1 tower, purging and regenerating the A-4 tower, and the purging gas is discharged outside through the A-4-2; part of the gas flows through A-1-4 and D-2-1 separately and enters a low-pressure buffer tank, and the regeneration of the A-4 tower is completed when the step is finished.

(4) secondary external average pressure drop: and (4) closing the program control valves A-4-2 and D-2-1 after the purge gas supply of the tower A-1 is finished. And continuously keeping the outlet end of the A-1 tower communicated with the outlet end of the A-4 tower which just finishes regeneration, wherein the gas in the dead space in the A-1 tower flows into the A-4 tower from the outlet end of the A-1 tower through the A-1-4 and A-4-4 valves. At the end of this step, the column pressures A-1 and A-4 are essentially in equilibrium.

(5) reverse emptying: after the step of the pressure equalization of the A-1 tower is finished, the program control valve A-1-4 and the valve A-4-4 are closed, the program control valve A-1-2 is opened, the adsorbed heavy component gas in the tower is reversely discharged, the reversely discharged gas is discharged as waste gas through the valve A-1-2, most of the adsorbed heavy component adsorbate is desorbed in the process, and the adsorbent is regenerated to a certain degree. At the end of the reverse-discharge step, the pressure in the column A-1 of the adsorption column should be substantially close to atmospheric pressure.

(6) Purging and regenerating: after the reverse releasing step is finished, opening A-1-4, A-1-2, A-2-4 and D-2-1 to communicate the outlet end of the A-1 tower with the outlet end of the adsorption tower A-2, and allowing part of the gas in the A-2 tower to flow from the outlet end of the A-2 tower to the A-1 tower through the A-2-4, A-1-4 and A-1-2 valves and to be discharged out of the system as regenerated waste gas. Part of the gas is shunted and enters a low-pressure buffer tank D-2 through a valve D-2-1. At the end of this step, valves A-1-2 and D-2-1 are closed and regeneration of the A-1 column is complete.

(7) Primary pressure equalization rising: keeping A-1-4 and A-2-4 open, and connecting the outlet end of A-1 tower with A-2 tower. And (3) introducing the gas in the A-2 tower into the A-1 tower through the A-2-4 and the A-1-4, equalizing the pressure of the A-1 tower, and after the step is finished, ensuring that the pressure of the A-2 tower is basically equal to that of the A-1 tower.

(8) And (4) secondary pressure equalization rising: after the A-1 tower completes the process of pressure equalization rising, the tower is ready for further pressure rising. The valves A-1-4 and A-2-4 are closed and the valves A-1-3 and A-3-3 are opened to communicate the outlet end of the column A-1 with the outlet end of the column A-3. And (3) introducing the gas in the A-3 tower into the A-1 tower through the A-3-3 tower, and equalizing the pressure of the A-1 tower, wherein the pressure of the A-3 tower is basically equal to that of the A-1 tower after the step is finished.

(9) Final pressure boosting: after the pressure equalizing step, the pressure in the tower A does not reach the working pressure of the adsorption step. At this point valves A-3-3 and A-1-3 are closed, A-1-5 and A-4-5 are opened, and the A-1 column is finally pressurized with a portion of the product gas being produced in the A-4 column until the A-1 column pressure substantially reaches the adsorption pressure. To this end, the A-1 column is completed in each step of one cycle, immediately before the next cycle is started. The same procedure as that carried out for A-1 was carried out for A-2, A-3 and A-4.

meanwhile, for the B-1 column:

(1) and (3) inflating: and opening the program control valve B-1-4 to enable the high-pressure gas buffer tank 31 to be communicated with the B-1, filling gas into the tower B-1 by the gas in the high-pressure gas buffer tank 31 until the pressure of the two towers is basically equal, and ending the pressurizing step. At this time, the programmable valve B-1-4 is closed.

(2) Air bleeding: opening the program control valves B-1-2 and C-1-1, communicating the columns B-1 and C-1, allowing the gas to enter the hydrogen absorption column C-1 from the column B-1 through the valves B-1-2 and C-1-1, and closing the valves B-1-2 and C-1-1 after all the hydrogen in the column B-1 is absorbed by the hydrogen storage alloy in the column C-1.

(3) reverse purging and regeneration: and opening valves D-2-2, B-1-3 and B-1-1, introducing gas into the B-1 tower from the low-pressure gas buffer tank 32 through the valves D-2-2 and B-1-3, performing displacement cleaning on the B-1 tower, introducing cleaned waste gas into a feed gas pipeline through the valve B-1-1 and pressurizing by a booster pump 7, mixing with the feed gas, and introducing into an adsorption tower for preliminary separation. After regeneration is complete, valves D-2-2, B-1-3 and B-1-1 are closed. To this end, the B-1 column is completed in each step of a cycle, immediately before the next cycle. For B-2, the same procedure as that carried out for B-1 was carried out.

Meanwhile, for the C-1 column:

(1) Gas absorption: opening valves B-1-2 and C-1-1, communicating the B-1 tower and the C-1 tower, allowing hydrogen in the B-1 tower to enter the C-1 tower, absorbing the hydrogen by the hydrogen storage alloy in the C-1 tower, and leaving inert gases such as nitrogen, argon and the like in the B-1 tower without being absorbed by metal hydride. After completion of the absorption, the valves B-1-2 and C-1-1 were closed.

(2) Product gas: and opening the program control valve C-1-2, communicating the hydrogen absorption tower C-1 with a product gas pipeline, analyzing hydrogen to enter the product gas pipeline, and closing the valve C-1-2 after the hydrogen analysis is finished. For C-2, the same procedure as that carried out for C-1 was carried out.

in the present application, it should be noted that, in each step as described above, except for the opened valve, the other valves are all in the closed state.

The present invention will be described in detail below by way of examples.