Metal hollow fiber hydrogen permeation membrane reactor for dehydrogenation purification of crude helium

Abstract

The invention relates to a metal hollow fiber hydrogen permeation membrane reactor for dehydrogenation purification of crude helium, a method for dehydrogenation purification of helium and application of the metal hollow fiber hydrogen permeation membrane reactor for dehydrogenation purification of crude helium. The metal hollow fiber hydrogen permeation membrane reactor comprises a metal hollow fiber hydrogen permeation membrane and a shell, the shell surrounds the periphery of the metal hollow fiber hydrogen permeation membrane, and an interception side serving as a space used for being filled with crude helium is arranged between the shell and the metal hollow fiber hydrogen permeation membrane. And a hollow inner cavity of the metal hollow fiber hydrogen permeation membrane is a permeation side serving as a reaction area. According to the metal hollow fiber hydrogen permeation membrane reactor for dehydrogenation and purification of the crude helium, hydrogen in the crude helium can be directly removed through a one-step reaction until the hydrogen meets the catalytic oxidation concentration standard, namely 3 vol% or below, so that a complex and high-energy-consumption separation process is avoided; the problem that hydrogen and helium are difficult to efficiently and selectively separate in the prior art is solved.

Description

Technical Field

[0001] The invention belongs to the field of membrane separation, and in particular relates to a method for purifying crude helium by dehydrogenation based on a metal hollow fiber hydrogen permeable membrane. Background Art

[0002] With the development of science and technology, ultrapure gases are increasingly used in semiconductor manufacturing, optical fiber production, scientific research experiments, medical treatment and other fields. Ultrapure helium has become an indispensable and important gas in these fields due to its low thermal conductivity, high chemical inertness and excellent permeability.

[0003] The main source of helium is crude helium, a byproduct of natural gas refining. In the production of liquefied natural gas (LNG), a nitrogen rejection unit (NRU) is used to remove nitrogen (-195.8°C) from natural gas to increase the purity of methane. Gases with lower boiling points, such as helium (-268.93°C) and hydrogen (-252.8°C), are concentrated and discharged together with nitrogen under the low temperature conditions of the NRU to become crude helium (70-85 vol% He-15-30 vol% H2) as a byproduct.

[0004] Since the molecular size, boiling point and other properties of helium and hydrogen are very similar, traditional separation technologies, such as cryogenic distillation and pressure swing adsorption, are difficult to achieve efficient selective separation.

[0005] In the traditional helium purification process, catalytic oxidative dehydrogenation is usually used to separate hydrogen and helium. If oxygen is directly introduced at a high hydrogen concentration (>3%) for catalytic oxidation of hydrogen, it will cause a sharp rise in temperature and make the hydrogen-oxygen mixture reach the explosion limit, posing a major threat to operational safety. Therefore, in the traditional catalytic oxidative dehydrogenation process, diluent gas is usually introduced to reduce the hydrogen concentration before oxidative dehydrogenation. However, this method requires the addition of additional separation equipment in the later stage of the purification process to remove the diluent gas, and the process is complicated. In addition, the later diluent gas separation also reduces the overall recovery rate of helium. Summary of the invention

[0006] In view of the deficiencies in the prior art, the present invention aims to provide a metal hollow fiber hydrogen permeable membrane reactor for dehydrogenation and purification of crude helium.

[0007] On the other hand, the present invention also provides a method for dehydrogenating and purifying crude helium based on a metal hollow fiber hydrogen permeable membrane, which is driven by a hydrogen consumption reaction and can directly remove hydrogen in a single step to meet the safe catalytic oxidation concentration standard. The method has low energy consumption and equipment cost, high separation efficiency and 100% helium recovery rate, and at the same time, the by-product hydrogen is prepared into synthesis gas or other chemical products, which has important industrial application value and market prospects.

[0008] In yet another aspect, the present invention further provides a use of a metal hollow fiber hydrogen permeable membrane reactor for dehydrogenation and purification of crude helium.

[0009] The present invention provides the following technical solutions.

[0010] [1] A metal hollow fiber hydrogen permeable membrane reactor for dehydrogenation and purification of crude helium, comprising a metal hollow fiber hydrogen permeable membrane and a shell, wherein the shell surrounds the metal hollow fiber hydrogen permeable membrane.

[0011] There is a retentate side between the shell and the metal hollow fiber hydrogen permeable membrane as a space for filling with crude helium gas, and the hollow inner cavity of the metal hollow fiber hydrogen permeable membrane is a permeate side as a reaction zone.

[0012] The housing is provided with a crude helium inlet, a purified helium outlet, a reaction gas inlet and a reaction product outlet.

[0013] The crude helium inlet is the inlet of the interception side, and the purified helium outlet is the outlet of the interception side.

[0014] The aforementioned reaction gas inlet is the inlet of the aforementioned permeate side, and the aforementioned reaction product outlet is the outlet of the aforementioned permeate side.

[0015] [2] The metal hollow fiber hydrogen permeable membrane reactor according to [1], wherein the crude helium gas inlet, the purified helium gas outlet, the reaction gas inlet and the reaction product outlet are all equipped with heat exchange components.

[0016] [3] The metal hollow fiber hydrogen permeable membrane reactor according to [1], wherein the shell is made of metal, quartz or ceramic.

[0017] [4] A method for dehydrogenating and purifying helium, using the metal hollow fiber hydrogen permeable membrane reactor described in any one of [1] to [3], the method comprising the following steps:

[0018] The step of generating a hydrogen partial pressure difference is as follows: introducing a reaction gas from a reaction gas inlet of the metal hollow fiber hydrogen permeable membrane and sweeping the permeate side to generate a transmembrane hydrogen partial pressure difference between the interception side and the permeate side;

[0019] Hydrogen separation step: preheating the crude helium as a raw material and introducing it into the interception side from the crude helium inlet of the metal hollow fiber hydrogen permeable membrane; driven by the transmembrane hydrogen partial pressure difference, hydrogen in the crude helium passes through the metal hollow fiber hydrogen permeable membrane and enters into the permeation side to react with the reaction gas to purify the crude helium; and discharging the purified helium from the outlet of the interception side; the reaction temperature of the hydrogen and the reaction gas in the hydrogen separation step is 700-1000° C.

[0020] [5] The method for purifying helium by dehydrogenation according to [4], wherein the reaction gas introduced in the hydrogen partial pressure difference generating step is CO2, benzene, toluene or unsaturated aldehyde.

[0021] [6] The method for purifying helium by dehydrogenation according to [4], wherein the flow rate of the aforementioned reaction gas introduced in the aforementioned hydrogen partial pressure difference generation step is 0.01 to 50 L / h, the temperature is 700 to 1000°C, and the pressure is atmospheric pressure.

[0022] [7] The method for purifying helium by dehydrogenation according to [4], wherein the volume percentage of hydrogen in the crude helium gas as a raw material added in the hydrogen separation step is 15 to 30 vol%.

[0023] [8] The method for purifying helium by dehydrogenation according to [4], wherein the flow rate of the crude helium introduced in the hydrogen separation step is 0.01 to 50 L / h, the pressure is 0.01 to 30 MPa, and the temperature is 700 to 1000°C.

[0024] [9] The method for purifying helium by dehydrogenation according to [4], wherein the volume concentration of hydrogen in the purified helium discharged from the outlet of the interception side after the aforementioned hydrogen separation step is less than 3%.

[0025]

[10] . Use of the metal hollow fiber hydrogen permeable membrane reactor described in any one of [1] to [3] for dehydrogenation and purification of crude helium.

[0026] Effects of the Invention

[0027] The metal hollow fiber hydrogen permeable membrane reactor for dehydrogenation and purification of crude helium of the present invention can directly remove hydrogen from crude helium to a concentration that meets the catalytic oxidation concentration standard, i.e., below 3 vol%, through a one-step reaction, thereby avoiding a complex and energy-intensive separation process and solving the problem of difficulty in efficiently and selectively separating hydrogen and helium in conventional technologies.

[0028] The method for purifying crude helium by dehydrogenation of the present invention utilizes the selectivity of the metal hollow fiber hydrogen permeable membrane for hydrogen, and can achieve the removal of hydrogen while preventing helium from passing through, so that there is no helium loss during the purification process, and a 100% helium recovery rate is achieved. Through the method for purifying crude helium by dehydrogenation of the present invention, the hydrogen concentration in the crude helium containing 15% to 30 vol% H2 can be reduced to less than 3%, so that O2 can be directly introduced into the catalytic oxidation system to remove residual hydrogen, thereby improving the efficiency of the entire purification system. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 It is a schematic structural diagram of a metal hollow fiber hydrogen permeable membrane reactor according to one embodiment.

[0030] Figure 2 It is a schematic structural diagram of a metal hollow fiber hydrogen permeable membrane reactor according to another embodiment.

[0031] Figure 3 The graph is a relationship between the volume concentration of hydrogen in the purified nitrogen obtained after purifying crude helium at different temperatures in Examples 1 to 7 and the temperature.

[0032] Figure 4 The graph is a relationship between feed pressure and temperature used in nitrogen purification of Examples 1 to 7 and pressure-driven hydrogen permeation of Comparative Examples 1 to 7.

[0033] Reference numerals

[0034] 1-1: Metal hollow fiber hydrogen permeable membrane

[0035] 1-2: Fixing parts

[0036] 2: Shell

[0037] 2-1: Main shell

[0038] 2-2: Upper shell

[0039] 2-3: Lower shell

[0040] 3: Heating rod

[0041] 4-1: Interception side

[0042] 4-2: Infiltration side

[0043] 5-1: Crude helium inlet

[0044] 5-2: Reaction gas inlet

[0045] 5-3: Purified helium outlet

[0046] 5-4: Reaction product outlet DETAILED DESCRIPTION

[0047] In order to better understand the present invention, the present invention is further described in detail below in conjunction with the embodiments, but the scope of protection claimed in the present invention is not limited to the scope represented by the embodiments. It should be understood by those skilled in the art that the content specifically described below is illustrative rather than restrictive, and should not be used to limit the scope of protection of the present disclosure.

[0048] In this specification, unless otherwise specified, percentages are by mass and temperatures are in degrees Celsius (°C).

[0049] [Metal hollow fiber hydrogen permeable membrane reactor]

[0050] The metal hollow fiber hydrogen permeable membrane reactor used for dehydrogenation and purification of crude helium contains a metal hollow fiber hydrogen permeable membrane and a shell.

[0051] The aforementioned metal hollow fiber hydrogen permeable membrane may be a metal hollow fiber hydrogen permeable membrane bundle, or may be a metal hollow fiber hydrogen permeable membrane group composed of a plurality of metal hollow fiber hydrogen permeable membrane bundles. Preferably, the aforementioned metal hollow fiber hydrogen permeable membrane is a metal hollow fiber hydrogen permeable membrane group composed of a plurality of metal hollow fiber hydrogen permeable membrane bundles. The number of metal hollow fiber membrane bundles in the aforementioned metal hollow fiber hydrogen permeable membrane group may be, for example, more than 2, without particular limitation. Preferably, the number of the aforementioned metal hollow fiber hydrogen permeable membrane bundles is 2 to 50. Furthermore, preferably, there is a gap between two adjacent metal hollow fiber membrane bundles, and the gap may be, for example, 1 to 10 mm, and more preferably 0.1 to 1 mm.

[0052] The shell can be made of metal, quartz or ceramic material, for example, and is not particularly limited as long as it is a commonly used material for the shell in a hydrogen separation reactor.

[0053] The aforementioned "metal hollow fiber hydrogen permeable membrane" is formed of metal and does not contain materials other than metal. The metal forming the metal hollow fiber hydrogen permeable membrane may be, for example, nickel-vanadium alloy, nickel-niobium alloy, iron-niobium alloy, etc. The composition of the corresponding metal hollow fiber hydrogen permeable membrane may be selected for different reaction gases.

[0054] The aforementioned metal hollow fiber membrane can be prepared by a phase inversion-sintering method or the like, with reference to the methods disclosed in, for example, CN112354511A, CN117695869A, CN117899800A, etc. Specifically, a preparation method comprising the following steps can be used for preparation: adding metal powder to an organic polymer solution and uniformly dispersing it to obtain a hollow fiber spinning casting solution, and then extruding the aforementioned hollow fiber spinning casting solution through a hollow fiber spinning die into a gel water bath for solidification to obtain a hollow fiber precursor; performing high-temperature sintering in a hydrogen-containing atmosphere or an air atmosphere to remove the aforementioned organic polymer, and then naturally cooling to room temperature to obtain a dense metal hollow fiber hydrogen permeable membrane.

[0055] The aforementioned housing is provided with a crude helium inlet, a purified helium outlet, a reaction gas inlet and a reaction product outlet.

[0056] There is a retentate side as a space for filling crude helium between the shell and the metal hollow fiber hydrogen permeable membrane, and the hollow inner cavity of the metal hollow fiber hydrogen permeable membrane is a permeate side as a reaction zone. The crude helium inlet is the inlet of the retentate side, the purified helium outlet is the outlet of the retentate side, the reaction gas inlet is the inlet of the permeate side, and the reaction product outlet is the outlet of the permeate side.

[0057] Through the above arrangement, two different paths, namely the retentate side and the permeate side, are formed in the metal hollow fiber hydrogen permeable membrane reactor. One path is from the crude helium inlet through the retentate side to the purified helium outlet, and the other path is from the reaction gas inlet through the permeate side to the reaction product outlet.

[0058] By adopting the above configuration, a transmembrane hydrogen partial pressure difference is generated between the retentate side and the permeate side, so that hydrogen on the retentate side enters the permeate side and reacts with the reaction gas introduced into the permeate side, thereby removing hydrogen.

[0059] Preferably, the aforementioned crude helium inlet, purified helium outlet, reaction gas inlet and reaction product outlet are all equipped with heat exchange components. When the aforementioned metal hollow fiber hydrogen permeable membrane reactor is used for dehydrogenation and purification of crude helium, it is necessary to utilize the reaction gas and hydrogen to undergo a hydrogen consumption reaction to remove hydrogen from the crude helium as the raw material gas, and such a hydrogen consumption reaction is carried out at a reaction temperature of, for example, 700 to 1000°C. Therefore, by installing heat exchange components at the aforementioned crude helium inlet and reaction gas inlet, the crude helium as the raw material and the reaction gas introduced into the reactor can be preheated to the reaction temperature. In addition, by installing heat exchange components at the purified helium outlet and the reaction product outlet, the heat carried by the gas discharged from the outlet can be recycled.

[0060] The aforementioned heat exchange component may be, for example, a shell-and-tube heat exchanger, a heating jacket, a condenser, and the like.

[0061] In addition, in some embodiments of the metal hollow fiber hydrogen permeable membrane reactor, it is preferred that a heating component for heating the crude helium gas introduced into the retentate side is further provided on the retentate side. Thus, the temperature of the crude helium gas can be adjusted to a suitable temperature for carrying out the hydrogen consumption reaction. The aforementioned heating component may be, for example, a heating rod, etc., without particular limitation.

[0062] Figure 1 A schematic structural diagram of a metal hollow fiber hydrogen permeable membrane reactor according to one embodiment is shown. Figure 1The metal hollow fiber hydrogen permeable membrane reactor shown contains a metal hollow fiber hydrogen permeable membrane 1-1, which is airtightly connected to the shell through a fixing member 1-2. In addition to playing the role of fixing the metal hollow fiber hydrogen permeable membrane 1-1, the fixing member 1-2 also separates the shell into an upper shell 2-2, a lower shell 2-3 and a main shell 2-1, and the main shell 2-1 is not connected to the upper shell 2-2 and the lower shell 2-3. A crude helium inlet 5-1 is provided on one side of the main shell 2-1, and a purified helium outlet 5-3 is provided on the other side. A reaction gas inlet 5-2 is provided at one end of the upper shell 2-2, and a reaction product outlet 5-4 is provided at one end of the lower shell 2-3. In this way, the space surrounded by the main shell 2-1 and the metal hollow fiber hydrogen permeable membrane 1-1 in the shell is formed as a retention side 4-1 as a space for filling with crude helium, and the inlet and outlet of the retention side 4-1 are a crude helium inlet 5-1 and a purified helium outlet 5-3, respectively. In addition, the hollow inner cavity of the metal hollow fiber hydrogen permeable membrane 1-1 is the permeate side 4-2 as the reaction zone, the reaction gas inlet 5-2 at one end of the upper shell 2-2 is the inlet of the aforementioned permeate side 4-2, and the reaction product outlet 5-4 at one end of the lower shell 2-3 is the outlet of the aforementioned permeate side 4-2. In addition, a heating rod 3 is also installed in the space of the interception side 4-1, and the heating rod 3 is used to heat the crude helium entering the permeate side 4-2. In addition, the crude helium inlet 5-1 and the reaction gas inlet 5-2 can also be installed with a heating rod or a heating jacket (not shown) for heating. In addition, the purified helium outlet 5-3 and the reaction product outlet 5-4 can also be installed with a shell-and-tube heat exchanger or a condenser for heat exchange.

[0063] The aforementioned fixing part 1-2 may also be any fixing part, as long as it can fix the metal hollow fiber hydrogen permeable membrane and separate the shell into an upper shell 2-2, a lower shell 2-3 and a main shell 2-1, so that the main shell 2-1 is not connected with the upper shell 2-2 and the lower shell 2-3. The aforementioned fixing part 1-2 may, for example, be composed of a clamping base and an array disk, and the clamping base is sealed and connected to the array disk through a metal ferrule. Alternatively, the aforementioned fixing part 1-2 is airtightly welded to the metal hollow fiber hydrogen permeable membrane 1-1 and the shell through nickel alloy solder.

[0064] Figure 2 It is a schematic structural diagram of a metal hollow fiber hydrogen permeable membrane reactor according to another embodiment. Figure 2The metal hollow fiber hydrogen permeable membrane reactor shown contains a metal hollow fiber hydrogen permeable membrane 1-1, a shell 2 and a fixing member 1-2. One side of the columnar portion of the shell 2 has a crude helium inlet 5-1 and the other side has a purified helium outlet 5-3. One end of the shell 2 has a reaction gas inlet 5-2 and the other end has a reaction product outlet 5-4. The metal hollow fiber hydrogen permeable membrane 1-1 is fixed by the fixing member 1-2 and the hollow inner cavity of the metal hollow fiber hydrogen permeable membrane 1-1 is connected to the reaction gas inlet 5-2 and the reaction product outlet 5-4. In this way, the space enclosed by the shell 2 and the metal hollow fiber hydrogen permeable membrane 1-1 forms a retention side 4-1 for filling with crude helium, and the inlet and outlet of the retention side 4-1 are the crude helium inlet 5-1 and the purified helium outlet 5-3, respectively. In addition, the hollow inner cavity of the metal hollow fiber hydrogen permeable membrane 1-1 is the permeate side 4-2 as the reaction zone, the reaction gas inlet 5-2 is the inlet of the aforementioned permeate side 4-2, and the reaction product outlet 5-4 is the outlet of the aforementioned permeate side 4-2. In addition, a heating rod 3 is also installed in the space of the interception side 4-1, and the heating rod 3 is used to heat the crude helium entering the permeate side 4-2. In addition, the crude helium inlet 5-1 and the reaction gas inlet 5-2 can also be installed with a heating rod or a heating jacket (not shown) for heating. In addition, the purified helium outlet 5-3 and the reaction product outlet 5-4 can also be installed with a shell-and-tube heat exchanger or a condenser for heat exchange.

[0065] [Method for purifying helium by dehydrogenation]

[0066] The method for dehydrogenating and purifying helium of the present invention uses the aforementioned metal hollow fiber hydrogen permeable membrane reactor, and the method comprises the following steps:

[0067] The step of generating a hydrogen partial pressure difference: introducing a reaction gas from a reaction gas inlet of the metal hollow fiber hydrogen permeable membrane and sweeping the permeate side to generate a transmembrane hydrogen partial pressure difference between the retentate side and the permeate side;

[0068] Hydrogen separation step: after preheating the crude helium as a raw material, the crude helium is introduced into the interception side from the crude helium inlet of the metal hollow fiber hydrogen permeable membrane; driven by the hydrogen partial pressure difference across the membrane, the hydrogen in the crude helium passes through the metal hollow fiber hydrogen permeable membrane into the permeation side to react with the reaction gas to purify the crude helium; the purified helium is discharged from the outlet of the interception side; the reaction temperature of the hydrogen and the reaction gas in the hydrogen separation step is 700-1000°C.

[0069] The reaction gas introduced in the aforementioned hydrogen partial pressure difference generation step is a gas that can react with hydrogen and be removed from the crude helium gas. Examples of such reaction gases include CO2, benzene, toluene, and unsaturated aldehydes.

[0070] By introducing the reaction gas from the reaction gas inlet of the metal hollow fiber hydrogen permeable membrane to the permeation side, the hydrogen partial pressure of the hollow inner cavity of the metal hollow fiber hydrogen permeable membrane is reduced, thereby forming a hydrogen partial pressure difference between the hollow inner cavity of the metal hollow fiber hydrogen permeable membrane and the outer side of the metal hollow fiber hydrogen permeable membrane. In the case where there is a hydrogen partial pressure difference between the hollow inner cavity of the metal hollow fiber hydrogen permeable membrane and the outer side of the metal hollow fiber hydrogen permeable membrane, since the metal hollow fiber hydrogen permeable membrane has the performance of selectively permeating hydrogen, the hydrogen contained in the crude helium introduced from the crude helium inlet of the metal hollow fiber hydrogen permeable membrane reactor permeates the metal hollow fiber hydrogen permeable membrane from the outer side of the metal hollow fiber hydrogen permeable membrane under the effect of the aforementioned hydrogen partial pressure difference and enters the hollow inner cavity of the metal hollow fiber hydrogen permeable membrane, i.e., the permeation side, and undergoes a hydrogen-consuming reaction with the reaction gas on the permeation side.

[0071] When the aforementioned reaction gas is CO2, the metal in the metal hollow fiber hydrogen permeable membrane may be, for example, an iron-nickel alloy. In this way, the metal hollow fiber hydrogen permeable membrane itself can act as a catalyst to catalyze the aforementioned hydrogen consumption reaction. Specifically, CO2 reacts with H2 that permeates into the permeation side, i.e., the hollow inner cavity of the metal hollow fiber hydrogen permeable membrane, as follows:

[0072] CO2+H2=CO+H2O

[0073] CO2+4H2=CH4+2H2O

[0074] The above reactions are all hydrogen-consuming reactions. CO, CH4, water vapor, etc. generated after the reaction are discharged from the reaction product outlet. In some embodiments of the method for purifying helium by dehydrogenation, the generated H2O can also be condensed and discharged by a condenser.

[0075] Through the above reaction, hydrogen on the permeate side is consumed, thereby reducing the hydrogen partial pressure, and the hydrogen partial pressure difference between the hollow inner cavity of the metal hollow fiber hydrogen permeable membrane and the outer side of the metal hollow fiber hydrogen permeable membrane is further increased, thereby forming a driving force for driving hydrogen to permeate from the outer side of the metal hollow fiber hydrogen permeable membrane to the hollow inner cavity.

[0076] The aforementioned reaction of CO2 and H2 is carried out at a reaction temperature of, for example, 700 to 1000°C.

[0077] In addition, since the helium in the crude helium introduced in the aforementioned hydrogen partial pressure difference generation step cannot enter the hollow inner cavity from the outside of the metal hollow fiber hydrogen permeable membrane, it gradually flows from the upstream of the aforementioned interception side to the downstream and is discharged from the outlet of the interception side, i.e., the purified helium outlet. As a result, helium will not be lost during the purification process, and all helium can be recovered. Among them, the aforementioned "upstream" and "downstream" refer to the relative positions of the crude helium inlet as the inlet and the purified helium outlet as the outlet in the interception side. In the interception side, the position closer to the crude helium inlet is regarded as the upstream, and the position closer to the purified helium outlet is regarded as the downstream.

[0078] In addition, when the aforementioned reaction gas is benzene, the hydrogenation reaction equation is as follows, and the rest is the same as when the reaction gas is CO2.

[0079] C6H6+3H2=C6H 12

[0080] In addition, when the aforementioned reaction gas is toluene, the hydrogenation reaction equation is as follows, and the rest is the same as when the reaction gas is CO2.

[0081] C7H8+3H2=C7H 14

[0082] When the aforementioned reaction gas is an unsaturated aldehyde, such as acrolein, the hydrogenation reaction equation is as follows, and the rest is the same as when the reaction gas is CO2.

[0083] C3H4O+2H2=C3H8O

[0084] In some embodiments of the method for purifying helium by dehydrogenation, preferably, the flow rate of the reaction gas introduced in the aforementioned hydrogen partial pressure difference generating step is 0.01-50 L / h, the temperature of the introduced reaction gas is, for example, 700-1000° C., and the pressure of the introduced reaction gas is normal pressure.

[0085] In some embodiments of the method for purifying helium by dehydrogenation, preferably, the proportion of hydrogen in the crude helium introduced in the aforementioned hydrogen separation step is, for example, 15 to 30 vol%. The aforementioned crude helium can be, for example, a by-product in the natural gas refining process. In the production process of liquefied natural gas (LNG), in order to improve the purity of methane, a nitrogen rejection unit (NRU) is used to remove nitrogen from natural gas, but gases with lower boiling points such as helium and hydrogen will be concentrated together with nitrogen under the low temperature conditions of the NRU and discharged as a by-product crude helium (70 to 85 vol% He-15 to 30 vol% H2).

[0086] In some embodiments of the method for purifying helium by dehydrogenation, preferably, the flow rate of the crude helium introduced in the aforementioned hydrogen separation step is 0.01 to 50 L / h, and the pressure of the introduced crude helium is 0.01 to 30 MPa. Preferably, the crude helium is preheated to 700 to 1000° C. before being introduced into the interception side. By preheating the crude helium to a reaction temperature range of 700 to 1000° C., such as the reaction temperature of the hydrogen consumption reaction, the hydrogen consumption reaction can be promoted. The aforementioned preheating can be implemented using, for example, a heat exchange component at the crude helium inlet.

[0087] In some embodiments of the method for purifying helium by dehydrogenation, preferably, the volume concentration of hydrogen in the purified helium discharged from the purified helium outlet after the hydrogen separation step is 3% or less. By removing hydrogen from crude helium to a concentration that meets the catalytic oxidation concentration standard, i.e., 3 vol% or less, a complex and energy-intensive separation process is avoided, thereby solving the problem of difficulty in efficiently and selectively separating hydrogen and helium in conventional technologies.

[0088] [use]

[0089] The metal hollow fiber hydrogen permeable membrane reactor of the present invention can be used for dehydrogenation and purification of crude helium. Specifically, the metal hollow fiber hydrogen permeable membrane reactor described above can be used to purify hydrogen in crude helium, a byproduct of natural gas refining, by the dehydrogenation and purification method described above.

[0090] In addition, the aforementioned method of dehydrogenation purification of crude helium can reduce the hydrogen concentration in the crude helium containing 15% to 30 vol% H2 to below 3%, so that O2 can be directly introduced and the residual hydrogen can be removed by catalytic oxidation, thereby improving the efficiency of the entire purification system.

[0091] Furthermore, when the reaction gas used in the aforementioned method of dehydrogenating and purifying crude helium is CO2, a means for converting and utilizing CO2 can also be provided, which realizes the conversion and utilization of CO2 while purifying the helium, thereby achieving the effect of reducing carbon emissions.

[0092] Example

[0093] Example 1

[0094] use Figure 1 The metal hollow fiber hydrogen permeable membrane reactor of the structure shown uses CO2 as the reaction gas to purify helium.

[0095] First, crude helium (85 vol% helium / 15 vol% hydrogen) was introduced into the retentate side of the membrane reactor at an inlet rate of 30 ml / min at a pressure of 1 MPa; CO2 was introduced into the permeate side of the membrane reactor at an inlet rate of 60 ml / min at a pressure of normal pressure. The crude helium and CO2 were preheated to 700° C. before being introduced into the reactor.

[0096] The purified helium was collected at the purified helium outlet, and the product after the hydrogen consumption reaction was collected at the reaction product outlet. The volume concentration of hydrogen therein was measured. The results are shown in Figure 3 .

[0097] Embodiments 2 to 7

[0098] The heating temperature of the pretreatment of the crude helium and CO2 before being introduced into the reactor was changed from 700°C to 750°C, 800°C, 850°C, 900°C, 950°C, and 1000°C, and the same treatment as in Example 1 was performed.

[0099] The purified helium was collected at the purified helium outlet, and the product after the hydrogen consumption reaction was collected at the reaction product outlet. The volume concentration of hydrogen therein was measured. The results are shown in Figure 3 .

[0100] Depend on Figure 3 It can be seen that in Examples 1 to 7, as the temperature gradually increases from 700° C. to 1000° C., the volume concentration of hydrogen in the purified helium gradually decreases from 3.2% to 0.57%.

[0101] Comparative Examples 1 to 7

[0102] The same metal hollow fiber hydrogen permeable membrane reactor as in Examples 1 to 7 was used respectively, and one end of the permeate side was melt-sealed by argon arc welding. The crude helium gas was heated to the same crude helium heating temperature as in Examples 1 to 7, and then the crude helium gas was pressurized by a reciprocating compressor to generate a transmembrane hydrogen partial pressure difference as a driving force for separation. The pressure was continuously applied on the interception side until the residual hydrogen concentration in the purified helium gas was the same as that in the example at the corresponding temperature. The pressure applied on the interception side was recorded, and the results are shown in Figure 4 .

[0103] Figure 4 The graph is a relationship between feed pressure and temperature used in nitrogen purification of Examples 1 to 7 and pressure-driven hydrogen permeation of Comparative Examples 1 to 7. Figure 4 It can be seen that as the temperature decreases from 1000° C. to 700° C., in order to obtain the same residual hydrogen concentration as that obtained by the method of the embodiment at the corresponding temperature, the feed pressure required for the comparative example increases from 2.33 MPa to 10.54 MPa.

[0104] The above embodiments illustrate that the method for purifying helium using a metal hollow fiber hydrogen permeable membrane reactor driven by a hydrogen consumption reaction provided by the present invention can effectively reduce the hydrogen partial pressure of the tube layer, generate driving force, and significantly reduce the feed pressure required in the helium purification process.

[0105] Obviously, the above embodiments of the present disclosure are merely examples for clearly illustrating the present disclosure, and are not limitations on the implementation methods of the present disclosure. For ordinary technicians in the relevant field, other different forms of changes or modifications can be made on the basis of the above description. It is impossible to list all the implementation methods here. All obvious changes or modifications derived from the technical solution of the present disclosure are still within the protection scope of the present disclosure.

Claims

1. A metal hollow fiber hydrogen permeable membrane reactor for dehydrogenation and purification of crude helium, It is characterized in that It contains a metal hollow fiber hydrogen permeable membrane and a shell, wherein the shell surrounds the metal hollow fiber hydrogen permeable membrane. A retentate side is provided between the shell and the metal hollow fiber hydrogen permeable membrane as a space for filling with crude helium gas, and the hollow inner cavity of the metal hollow fiber hydrogen permeable membrane is a permeate side as a reaction zone. The housing is provided with a crude helium inlet, a purified helium outlet, a reaction gas inlet and a reaction product outlet. The crude helium inlet is the inlet of the interception side, and the purified helium outlet is the outlet of the interception side. The reaction gas inlet is the inlet of the permeate side, and the reaction product outlet is the outlet of the permeate side.

2. The metal hollow fiber hydrogen permeable membrane reactor according to claim 1, in, The crude helium inlet, the purified helium outlet, the reaction gas inlet and the reaction product outlet are all equipped with heat exchange components.

3. The metal hollow fiber hydrogen permeable membrane reactor according to claim 1, in, The shell is made of metal, quartz or ceramic.

4. A method for purifying helium by dehydrogenation, It is characterized in that The method uses the metal hollow fiber hydrogen permeable membrane reactor according to any one of claims 1 to 3, and comprises the following steps: A hydrogen partial pressure difference generating step: introducing a reaction gas from a reaction gas inlet of the metal hollow fiber hydrogen permeable membrane and sweeping the permeate side to generate a transmembrane hydrogen partial pressure difference between the retentate side and the permeate side; Hydrogen separation step: preheating the crude helium as a raw material and introducing it into the interception side from the crude helium inlet of the metal hollow fiber hydrogen permeable membrane; driven by the transmembrane hydrogen partial pressure difference, the hydrogen in the crude helium passes through the metal hollow fiber hydrogen permeable membrane and enters the permeation side to react with the reaction gas to purify the crude helium; and discharging the purified helium from the outlet of the interception side; the reaction temperature of the hydrogen and the reaction gas in the hydrogen separation step is 700-1000° C.

5. The method for purifying helium by dehydrogenation according to claim 4, in, The reaction gas introduced in the hydrogen partial pressure difference generation step is CO 2 , benzene, toluene or unsaturated aldehydes.

6. The method for purifying helium by dehydrogenation according to claim 4, in, The flow rate of the reaction gas introduced in the hydrogen partial pressure difference generating step is 0.01 to 50 L / h, the temperature is 700 to 1000° C., and the pressure is normal pressure.

7. The method for purifying helium by dehydrogenation according to claim 4, in, The volume percentage of hydrogen in the crude helium gas as a raw material added in the hydrogen separation step is 15-30 vol%.

8. The method for purifying helium by dehydrogenation according to claim 4, in, The crude helium introduced in the hydrogen separation step has a flow rate of 0.01 to 50 L / h, a pressure of 0.01 to 30 MPa, and a temperature of 700 to 1000°C.

9. The method for purifying helium by dehydrogenation according to claim 4, in, The volume concentration of hydrogen in the purified helium discharged from the outlet of the retentate side after the hydrogen separation step is 3% or less.

10. Use of the metal hollow fiber hydrogen permeable membrane reactor according to any one of claims 1 to 3 in dehydrogenation and purification of crude helium.

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