TWI674143B - A method for promoting separation of a gas mixture - Google Patents

Abstract

The present invention provides a method for separating a gas from a gas mixture. In this method, a gas mixture containing hydrogen is first introduced into the intake side of a gas separation device, and the pressure on the permeate side of the gas separation device is reduced to less than the normal atmospheric pressure (1 atm). Under this operating condition, when the hydrogen partial pressure difference between the inlet side and the permeate side is greater than 0 atm and less than or equal to 5 atm, the hydrogen in the gas mixture can penetrate through the membrane element to a large extent and be collected on the permeate side. This method uses the low pressure (less than 1 atm) on the permeate side to increase the permeation rate and permeation coefficient of hydrogen to more effectively separate hydrogen from the gas mixture.

Description

Method for promoting separation of gas mixture

The present invention relates to a separation method, and more particularly, to a method for promoting separation of a gaseous mixture.

With the advancement of science and technology, energy demand is increasing. However, with the rising awareness of environmental protection and the limited resources of the earth, the development of green energy is being increasingly valued. Since the generation of green energy does not produce pollution, it does not cause additional burden on the environment. Furthermore, green energy technology generates energy by converting renewable resources, so it can be used by users on a sustainable basis, avoiding the dilemma of resource exhaustion.

Proton Exchange Membrane Fuel Cell (PEMFC) in green energy only needs to pass in hydrogen to generate electrons through the action of a catalyst, and the generated electrons can flow into external circuits to generate electricity. Since the content of hydrogen in nature is extremely large and can come from hydrocarbons, the process of generating electricity generates only water. Therefore, the engineering community has recently devoted itself to the research of proton exchange membrane fuel cells. Among them, although the content of hydrogen in nature is extremely large, it coexists with other gases in the atmospheric environment, so it is not easy to be separated. Similarly, if the When the product obtains hydrogen, the hydrogen is also easily mixed with other produced gases in the process of hydrocarbon cracking to produce hydrogen.

According to this, the hydrogen in the mixed gas cannot be easily separated, and it is difficult to apply it to a proton exchange membrane fuel cell. Furthermore, if a mixed gas containing other gases (such as carbon monoxide) is passed into the fuel cell, these other gases are liable to poison and damage the catalyst and / or proton exchange membrane in the fuel cell.

In view of this, it is urgent to provide a method for separating mixed gas to improve the conventional defect that it is not easy to effectively separate hydrogen from the mixed gas.

Therefore, one aspect of the present invention is to provide a separation method for promoting a gas mixture. This separation method reduces the pressure on the permeate side to less than 1 atm by a decompression unit, so that the hydrogen gas in the mixed gas can more effectively penetrate the membrane element For higher hydrogen production.

According to one aspect of the present invention, a method for promoting separation of mixed gas is proposed. In this separation method, a mixed gas is first provided, and the mixed gas is introduced into a gas separation device. The mixed gas includes hydrogen, and the content of the hydrogen is greater than or equal to 20 volume percent. The gas separation device includes a thin film element, and the thin film element separates a high pressure side and a permeate side, wherein the mixed gas has a hydrogen partial pressure at a high pressure measurement. Then, the pressure on the permeate side is reduced to less than 1 atm, so that the pressure difference between the hydrogen partial pressure on the high pressure side and the pressure on the permeate side is greater than 0 atm and less than or equal to 5 atm, so that hydrogen passes through the membrane element and flows out from the permeate side. .

According to an embodiment of the present invention, the step of maintaining the pressure on the permeate side at less than 1 atm uses a vacuum pump.

According to another embodiment of the present invention, the aforementioned mixed gas further includes nitrogen, carbon monoxide, carbon dioxide, and / or methane.

According to another embodiment of the present invention, the aforementioned thin film element includes a palladium film.

According to another embodiment of the present invention, the aforementioned pressure difference is greater than 0 atm and less than or equal to 4 atm.

According to yet another embodiment of the present invention, the aforementioned pressure difference is 2 atm to 4 atm.

According to yet another embodiment of the present invention, when the hydrogen gas passes through the thin film element, the temperature of the thin film element is 300 ° C to 400 ° C.

By applying the separation method of the mixed gas of the present invention, the hydrogen in the mixed gas can be effectively separated by a membrane element. When a pressure reduction unit is used to adjust the pressure on the permeate side, the hydrogen gas in the mixed gas can penetrate the membrane element more effectively, thereby improving its permeation properties. Furthermore, when the mixed gas contains a gas other than hydrogen, these gases can further effectively increase the permeability coefficient of hydrogen, and enhance the separation effect of the membrane element on the mixed gas.

100‧‧‧ Method

110/120/130 / 140‧‧‧ Operation

200‧‧‧Gas separation device

210‧‧‧ separation tank

210a‧‧‧Slot space

211‧‧‧ membrane separation unit

211a‧‧‧ open end

213‧‧‧ thin film element

215‧‧‧Heating unit

220‧‧‧Gas tank

220a / 240a‧‧‧pipe

221 / 241‧‧‧Valve

223‧‧‧Pressure gauge

230 / 240‧‧‧Gas collection tank

231‧‧‧Decompression unit

311/313/315 / 317‧‧‧ Polyline

311a / 311b / 313a / 313b / 315a / 315b / 317a / 317b‧‧‧ Polyline

321/323/325 / 327‧‧‧ Polyline

321a / 321b / 323a / 323b / 325a / 325b / 327a / 327b‧‧‧ Polyline

411a / 411b / 413a / 413b / 415a / 415b / 417a / 417b‧‧‧ Polyline

421a / 421b / 423a / 423b / 425a / 425b / 427a / 427b‧‧‧ Polyline

511a / 511b / 513a / 513b / 521a / 521b / 523a / 523b / 531a / 531b / 533a / 533b / 541a / 541b / 543a / 543b‧‧‧ Polyline

611/613/615/617/621/623/625 / 627‧‧‧ Polyline

In order to have a more complete understanding of the embodiments of the present invention and its advantages, please refer to the following description and cooperate with the corresponding drawings. It must be emphasized that the various features are not drawn to scale and are for illustration purposes only. The contents of the related drawings are described as follows: [Fig. 1] Fig. 1 is a schematic flow chart showing a method for separating a mixed gas according to an embodiment of the present invention.

[Fig. 2] A schematic diagram showing a gas separation device according to an embodiment of the present invention.

[Fig. 3A] It shows the flow rate of hydrogen permeation through the membrane element and its improvement rate according to Examples 1-1 to 1-4 and Comparative Examples 1-1 to 1-4 according to the present invention under various hydrogen partial pressure differences. .

[FIG. 3B] It shows the examples 2-1 to 2-4 and comparative examples 2-1 to 2-4 according to the present invention. Under various hydrogen partial pressure differences, the flow rate of hydrogen permeating through the membrane element and its improvement rate. .

[FIG. 4A] It shows the flow rate of hydrogen permeating through the membrane element under various hydrogen partial pressure differences according to Comparative Examples 1-1 to 2-4 of the present invention.

[FIG. 4B] It shows the flow rate of hydrogen permeating through the membrane element under various hydrogen partial pressure differences according to Examples 1-1 to 2-4 of the present invention.

[FIG. 5] It shows the permeability coefficients of hydrogen permeating through the membrane element under various hydrogen partial pressure differences according to Examples 1-1 to 2-4 and Comparative Examples 1-1 to 2-4 according to the present invention.

[Fig. 6] It is a graph showing the improvement rate of the hydrogen flow rate of each of the separation temperature and the hydrogen partial pressure difference in Examples 1-1 to 2-4 of the present invention compared with Comparative Examples 1-1 to 2-4.

The manufacture and use of the embodiments of the invention are discussed in detail below. It is understood, however, that the embodiments provide many applicable inventive concepts that It can be implemented in a variety of specific content. The specific embodiments discussed are for illustration only and are not intended to limit the scope of the invention.

Please refer to FIG. 1 and FIG. 2, wherein FIG. 1 is a schematic flow chart showing a method for separating a mixed gas according to an embodiment of the present invention, and FIG. 2 is a schematic view showing a gas separation device according to an embodiment of the present invention . In the method 100, a mixed gas system containing hydrogen is first provided, and the mixed gas is introduced into the gas separation device 200, as shown in operations 110 and 120. The mixed gas can be stored in the gas tank 220, and whether the mixed gas is passed into the separation tank 210 of the gas separation device 200 through the pipeline 220a is controlled by a valve 221. Among them, in order to facilitate the monitoring of the gas pressure in the separation tank 210, a pressure gauge 223 is disposed on the pipeline 220a and is interposed between the valve 221 and the outlet end of the pipeline 220a. In some embodiments, the pressure gauge 223 can also be disposed on the tank body of the separation tank 210. In some embodiments, the mixed gas may include greater than or equal to 20 volume percent hydrogen. In some embodiments, the content of hydrogen in the mixed gas may be greater than or equal to 50% by volume. In other embodiments, the content of hydrogen in the mixed gas may be greater than or equal to 80% by volume. In some embodiments, the mixed gas may optionally include nitrogen, carbon monoxide, carbon dioxide, methane, other suitable gases, or any combination of the foregoing gases. In some embodiments, the mixed gas may contain only hydrogen and no other gases. In some embodiments, the gas tank 220 may be omitted, and various gases in the mixed gas may come directly from the respective gas sources, and may be mixed uniformly in the pipeline 220a before entering the separation tank 210, or The mixing tank is uniformly mixed and then passed into the separation tank 210. In some embodiments, the gas tank 220 may be It is omitted, and the pipeline 220a is directly connected to the gas generating device to directly pass the mixed gas generated by the gas generating device into the separation tank 210.

The separation tank 210 may include a film separation unit 211 and a heating unit 215. The membrane separation unit 211 is disposed on the casing of the separation tank 210, and at least a part of the membrane separation unit 211 is located in the separation tank 210. One end of the membrane separation unit 211 is open and the other end is closed. The closed end of the membrane separation unit 211 is located in the separation tank 210. Adjacent to the closed end, the thin film separation unit 211 has a thin film element 213, and the whole of the thin film element 213 is located in the separation groove 210. In some embodiments, the membrane element 213 may include, but is not limited to, a palladium membrane, other suitable gas separation membranes, or any combination of the foregoing materials. The open end 211 a of the membrane separation unit 211 is located outside the separation tank 210 and communicates with the first gas collection tank 230. In some embodiments, the first gas collection tank 230 may be omitted, and the open end 211a is directly connected to a device to be supplied with hydrogen. The heating unit 215 is disposed on an inner wall of the separation tank 210. Preferably, the heating area of the heating unit 215 can cover the entire film element 213 to ensure that the film element 213 can be effectively heated.

In the membrane separation unit 211, the membrane element 213 can be penetrated by the hydrogen gas in the mixed gas, and the hydrogen can be separated from the mixed gas. The hydrogen gas permeating through the membrane element 213 can flow into the first gas collection tank 230 from the open end 211 a of the membrane separation unit 211. Among them, since the open end 211a is configured to allow permeate gas to flow out, the open end 211a of the membrane separation unit 211 may also be referred to as a permeate side.

Second, the separation tank 210 may be provided with another pipeline 240a, wherein this pipeline 240a may be connected to the second gas collection tank 240, and the pipeline 240a may be configured with a valve 241 to control whether the gas in the separation tank 210 passes into the second The gas collection tank 240.

When the mixed gas is to be introduced into the gas tank 220 of the gas separation device 200, the valve 221 must be opened and the valve 241 is closed to allow the mixed gas to pass from the gas tank 220 into the separation tank 210 and stay therein. With the increase of the mixed gas flow rate, the pressure of the gas in the separation tank 210 is gradually increased by the monitoring of the pressure gauge 223. Since the gas pressure of the separation tank 210 is gradually increased, the space 210a in the tank of the separation tank 210 may be referred to as a high-pressure side. In other words, the two sides of the membrane element 213 are a high-pressure side and a permeate side, wherein the high-pressure side refers to one side filled with the gas to be separated, and the permeate side refers to a side after the permeable gas penetrates through the membrane element 213. In the high-pressure side, with the introduction of the mixed gas, the hydrogen partial pressure of the mixed gas on the high-pressure side gradually increases. When the pressure difference between the hydrogen partial pressure on the high-pressure side (i.e., the space 210a in the tank) and the permeate side (i.e., the open end 211a of the membrane separation unit 211) is greater than 0 atm and less than or equal to 5 atm, hydrogen in the mixed gas can permeate through The membrane element 213 undergoes a separation process, so hydrogen can flow through the membrane separation unit 211, flow out from the permeate side, and be collected in the first gas collection tank 230 to obtain hydrogen, as shown in operations 130 and 140 in FIG. 1. During the separation process, the pressure on the permeate side is reduced to less than 1 atm, and the pressure on the permeate side is reduced to less than 1 atm by the decompression unit 231. The decompression unit 231 is connected to the open end 211a of the membrane separation unit 211, and the decompression unit 231 is disposed between the open end 211a and the first gas collection tank 230. In some embodiments, the decompression unit 231 It may include, but is not limited to, a vacuum pump, other suitable decompression units, or any combination of these units. In some embodiments, the pressure on the permeate side of the thin film element 213 may be 0.5 atm to 0.7 atm.

It should be understood that, since the thin-film element 213 allows only hydrogen in the mixed gas to permeate through, the only gas that can flow through the permeation side is hydrogen. According to this, the aforementioned pressure difference between the hydrogen partial pressure on the high pressure side and the permeate side refers to the pressure difference between the hydrogen partial pressure on the high pressure side and the hydrogen partial pressure on the permeate side. If the pressure difference between the high-pressure side and the permeate side is greater than 5 atm, although the hydrogen in the mixed gas can still penetrate the membrane element 213, the excessively high gas pressure must be matched with a device capable of withstanding higher pressures or a device capable of forming a high pressure, It is easy to significantly increase the equipment cost of the separation method. Moreover, a pressure difference greater than 5 atm has no significant effect on the penetration effect. In some embodiments, the pressure difference between the high-pressure side and the permeate side is greater than 0 and less than or equal to 4 atm. In some embodiments, the pressure difference between the high pressure side and the permeate side is 2 atm to 3 atm.

When the separation process is performed, if the pressure on the permeate side is not less than 1 atm, the hydrogen in the mixed gas is less likely to penetrate through the membrane element 213, and the separation effect of the membrane element 213 on hydrogen is reduced.

When the separation process is performed, the heating unit 250 may heat the thin film element 213 of the thin film separation unit 211 to adjust the operating temperature of the separation process and optimize the separation effect of the thin film element 213 to separate hydrogen in the mixed gas. In some embodiments, the set temperature of the heating unit 250 is adjusted according to the operating temperature of the selected thin film element 213. The working temperature of the thin film element 213 refers to the temperature at which the thin film element 213 can separate the mixed gas. In some embodiments, the operating temperature of the separation process may be 300 ° C to 400 ° C. when When the operating temperature of the separation process is 300 ° C to 400 ° C, the membrane element 213 has a better separation effect for the hydrogen in the mixed gas.

It can be understood that after the hydrogen gas in the mixed gas penetrates through the membrane element 213, the remaining gas system in the mixed gas remains in the separation tank 210. Therefore, if these residual gases are not discharged from the separation tank 210, the mixed gas will no longer pass into the separation tank 210 due to the influence of the pressure in the tank. Accordingly, the valve 221 can be closed, and the valve 241 is opened, so that the remaining gas can flow into the second gas collection tank 240 through the pipeline 240a. When the gas pressures of the separation tank 210 and the second gas collection tank 240 reach equilibrium, the valve 241 is closed, and the valve 221 can be opened to allow the mixed gas in the gas tank 220 to pass into the separation tank 210 and perform again. Separation process. In some embodiments, the second gas collection tank 240 may be omitted, and the pipeline 240a is directly connected to the atmospheric environment to discharge the remaining gas directly to the environment or to a gas processing device. In some embodiments, the pressure monitoring of the gas tank 220, the pressure monitoring of the separation tank 210, and the opening or closing of the valve 221 and the valve 241 can be performed by an automatic operation device to allow real-time and automatic access to the mixed gas and The remaining gas is discharged, and the hydrogen can be continuously separated from the mixed gas.

In some embodiments, it can be understood that when the mixed gas in the gas tank 220 is only composed of hydrogen and another gas, after the separation process is performed, the gas remaining in the separation tank 210 is the only other gas. A gas. According to this, for this other gas, since the hydrogen gas mixed with it has been separated, the purity of this other gas is relatively improved.

It should be noted that the gas separation device 200 shown in FIG. 2 is only used for illustration, and the component configuration of the gas separation device of the present invention is not limited thereto. In other embodiments, the membrane element in the membrane separation unit of the present invention can separate the inside of the separation tank into a high-pressure side and a permeate side, and the pipeline of the gas tank and the second gas collection tank are both connected to the high-pressure side, and the first gas The collection tank is connected to the permeate side.

According to this, the mixed gas separation method and the gas separation device of the present invention can effectively separate the hydrogen in the mixed gas by the membrane element of the membrane separation unit, and can reuse the hydrogen effectively. Among them, by providing a decompression unit on the permeation side of the membrane element, the pressure on the permeation side can be reduced to less than 1 atm, which helps to improve the permeation effect of hydrogen through the membrane element.

The following uses examples to illustrate the application of the present invention, but it is not intended to limit the present invention. Any person skilled in the art can make various changes and decorations without departing from the spirit and scope of the present invention.

Preparation of mixed gas

The preparation of the following mixed gas in the present invention is not particularly limited, and it is a mixed gas according to the ratios listed in Table 1.

Separation of mixed gas Example 1-1

In Example 1-1, the aforementioned gas example 1 was passed into the aforementioned gas separation device, and the temperature of the heating unit was set to 320 ° C. The thin film element of the gas separation device is a palladium thin film.

Then, adjust the flow rate of the mixed gas according to the conditions listed in Table 2-1 below to adjust the high-pressure side pressure in the separation tank, and use the decompression unit to reduce the pressure at the permeate end to less than 1 atm to reduce the high-pressure side. The partial pressure difference of hydrogen from the permeate side is controlled to 2 atm, 3 atm, 4 atm, and 5 atm. Next, the flow rate (mL / sec) of hydrogen permeating through the membrane element was measured at each hydrogen partial pressure difference.

Examples 1-2 to 1-4

Examples 1-2 to 1-4 use the same process steps as the mixed gas separation method of Example 1-1 to measure the flow rate (mL / sec) of hydrogen permeating through the membrane element under each hydrogen partial pressure difference ), The difference is that Examples 1-2 to 1-4 are passed through Gas Example 2, Gas Example 3, and Gas Example 4 to the gas separation device, respectively.

Example 2-1

Example 2-1 uses the same process steps as the separation method of the mixed gas of Example 1-1, except that the temperature of the heating unit of the gas separation device of Example 2-1 is set to 380 ° C, and implemented Example 2-1 is to adjust the pressure on the high pressure side and the permeate side according to Table 2-2 shown below. Same as in Example 1-1, the flow rate (mL / sec) of hydrogen permeation through the membrane element of Example 2-1 was measured under the partial hydrogen pressure difference of 2 atm, 3 atm, 4 atm, and 5 atm.

Examples 2-2 to 2-4

Examples 2-2 to 2-4 use the same process steps as the mixed gas separation method of Example 2-1 to measure the flow rate (mL / sec) of hydrogen permeating through the membrane element at each hydrogen partial pressure difference ), The difference is that Example 2-2 to Example 2-4 are respectively passed into Gas Example 2, Gas Example 3 and Gas Example 4 to the gas separation device.

Comparative Example 1-1

Comparative Example 1-1 uses the same process steps as the separation method of the mixed gas of Example 1-1, except that the gas separation device of Comparative Example 1-1 does not use a decompression unit to reduce the pressure on the permeate side to less than 1atm, and Comparative Example 1-1 adjusts the flux of the mixed gas according to Table 3-1 shown below. Then, the flow rate (mL / sec) of hydrogen permeating through the membrane element was measured at a hydrogen partial pressure difference of 2 atm, 3 atm, 4 atm, and 5 atm.

Comparative Example 1-2 to Comparative Example 1-4

Comparative Examples 1-2 to 1-4 use the same process steps as the separation method of the mixed gas of Comparative Example 1-1 to measure the flow rate (mL / sec) of hydrogen permeating through the membrane element under each hydrogen partial pressure difference. ), The difference is that Comparative Example 1-2 to Comparative Example 1-4 were passed through Gas Example 2, Gas Example 3, and Gas Example 4 to the gas separation device, respectively.

Comparative Example 2-1

Comparative Example 2-1 uses the same process steps as the separation method of the mixed gas of Comparative Example 1-1, except that the temperature of the heating unit of the gas separation device of Comparative Example 2-1 is set to 380 ° C and is based on Table 3-2 shown below adjusts the flux of the mixed gas. Identical to Comparative Example 1-1, the flow rate (mL / sec) of the hydrogen permeation through the membrane element of Comparative Example 2-1 was measured at a hydrogen partial pressure difference of 2 atm, 3 atm, 4 atm, and 5 atm.

Comparative Example 2-2 to Comparative Example 2-4

Comparative Examples 2-2 to 2-4 use the same process steps as the separation method of the mixed gas of Comparative Example 2-1 to measure the flow rate (mL / sec) of hydrogen permeating through the membrane element at each hydrogen partial pressure difference ), The difference is that Comparative Example 2-2 to Comparative Example 2-4 were passed through Gas Example 2, Gas Example 3, and Gas Example 4 to the gas separation device, respectively.

Please refer to FIG. 3A, which shows Examples 1-1 to 1-4 and Comparative Examples 1-1 to 1-4 according to the present invention. Under various hydrogen partial pressure differences, hydrogen permeates through the film. Component flow and its improvement rate. Among them, the broken lines 311a, 313a, 315a, and 317a respectively represent the flow results measured in Example 1-1 to Example 1-4, and the broken lines 311b, 313b, 315b, and 317b respectively represent Comparative Example 1-1 to Comparative Example 1 -4 Measured flow results.

In FIG. 3A, the improvement rates are respectively based on the flow results obtained in Examples 1-1 to 1-4 and Comparative Examples 1-1 to 1-4, and various calculations are performed by the following formula (I) Flow rate of mixed gas under different hydrogen partial pressure difference using decompression unit (ie, Example 1-1 to Example 1-4) and non-decompression unit (ie, Comparative Example 1-1 to Comparative Example 1-4) Improvement rate. The calculated improvement rates are shown by the broken lines 311, 313, 315, and 317 in FIG. 3A, respectively.

In formula (I), F _v represents a hydrogen flow rate when a decompression unit is used, and F _nv represents a hydrogen flow rate when a decompression unit is not used.

Under a variety of mixed gas and various hydrogen partial pressure differences, the hydrogen flow rate obtained by using a decompression unit to adjust the pressure on the permeate side is higher than that without a decompression unit. Therefore, by reducing the pressure on the permeate side to less than 1 atm, the separation technology contributes to the separation effect of hydrogen in the mixed gas. In addition, compared with a larger hydrogen partial pressure difference, when the hydrogen partial pressure difference is small, the configuration of the decompression unit can effectively improve the driving force of hydrogen permeation through the membrane element, so it has a better improvement rate.

Please refer to FIG. 3B, which shows Examples 2-1 to 2-4 and Comparative Examples 2-1 to 2-4 according to the present invention. Under pressure difference, the flow rate of hydrogen permeating through the membrane element and its improvement rate. Among them, the broken lines 321a, 323a, 325a, and 327a respectively represent the flow results measured in Example 2-1 to Example 2-4, and the broken lines 321b, 323b, 325b, and 327b respectively represent Comparative Example 2-1 to Comparative Example 2 -4 Measured flow results. Similarly, the improvement rate of FIG. 3B is calculated according to formula (I), and the calculated results are shown as broken lines 321, 323, 325, and 327, respectively.

Same results as in Fig. 3A. At a separation temperature of 380 ° C, the pressure on the permeate side is reduced to less than 1 atm by a decompression unit. When the separation process is performed, the obtained hydrogen flow is higher than that without a decompression unit In the case where the partial pressure difference of hydrogen is small, the configuration of the decompression unit can obtain a better improvement rate.

Please refer to FIG. 4A and FIG. 4B, wherein FIG. 4A shows Comparative Examples 1-1 to 1-4 and Comparative Examples 2-1 to 2-4 according to the present invention. Under various hydrogen partial pressure differences, The flow rate of hydrogen permeating through the membrane element, and FIG. 4B is a diagram illustrating Examples 1-1 to 1-4 and Examples 2-1 to 2-4 according to the present invention under various hydrogen partial pressure differences The flow of hydrogen permeates through the membrane element. Among them, the broken lines 411a, 413a, 415a, and 417a respectively represent the flow rate results measured in Comparative Example 2-1 to Comparative Example 2-4; the broken lines 411b, 413b, 415b, and 417b respectively represent Comparative Example 1-1 to Comparative Example 1- 4 The measured flow results; the broken lines 421a, 423a, 425a, and 427a represent the measured flow results of Example 2-1 to Example 2-4; the broken lines 421b, 423b, 425b, and 427b represent Example 1- Flow rate results from 1 to Examples 1-4. According to FIG. 4A and FIG. 4B, it is known that for various mixed gases In particular, when the temperature of the separation process is high, the hydrogen in the mixed gas can easily penetrate through the membrane element, so it has a higher hydrogen flow rate.

Secondly, according to the formula of the permeability of the membrane element (as shown in the following formula (II)) and the flow rate results obtained in the foregoing examples and comparative examples, calculate the various mixtures when the decompression unit is used and when the decompression unit is not used. Permeability coefficient of gas under 320 ℃ or 380 ℃ and each partial pressure difference of hydrogen.

In formula (II), K represents the permeability coefficient (Permeance; the unit is mol m ² s ^-1 Pa); Represents the hydrogen flow rate (unit is mol s ^-1 ); A represents the surface area of the thin film element (unit is m ² ); and ΔP represents the hydrogen partial pressure difference (unit is Pa). The permeability coefficients obtained in the calculations of the examples and comparative examples are shown in FIG. 5.

In FIG. 5, the broken line 511a represents the permeability coefficient calculated in Example 2-1, the broken line 513a represents the permeability coefficient calculated in Example 1-1, the broken line 511b represents the permeability coefficient calculated in Comparative Example 2-1, and the broken line 513b represents The permeability coefficient calculated in Comparative Example 1-1; the polyline 521a represents the permeability coefficient calculated in Example 2-2, the polyline 523a represents the permeability coefficient calculated in Example 1-2, and the polyline 521b represents the calculated coefficient in Comparative Example 2-2. Permeability coefficient. Polyline 523b represents the permeability coefficient calculated in Comparative Example 1-2. Polyline 531a represents the permeability coefficient calculated in Example 2-3. Polyline 533a represents the permeability coefficient calculated in Example 1-3. Polyline 531b represents the comparative example. 2-3 calculated permeability coefficient, polyline 533b represents the permeability coefficient calculated in Comparative Example 1-3; and polyline 541a represents the permeability coefficient calculated in Example 2-4, and polyline 543a represents the permeability calculated in Example 1-4 Coefficient 541b represents the permeability coefficient calculated in Comparative Example 2-4, and polyline 543b represents the permeability coefficient calculated in Comparative Example 1-4.

According to the results obtained in FIG. 5, under the partial pressure differences of various mixed gases and hydrogen, compared with the comparative example without a decompression unit, the embodiment using the decompression unit to reduce the pressure on the permeate side to less than 1 atm has higher Coefficient of permeability. Furthermore, the high temperature environment helps to increase the permeability coefficient of hydrogen permeating through the membrane element.

In addition, in order to compare the influence of the gas composition of the mixed gas on the hydrogen permeation effect, please refer to FIG. 6, which shows examples 1-1 to 2- of the present invention compared with comparative examples 1-1 to 2-4. 4 The improvement rate of hydrogen flow at each separation temperature and hydrogen partial pressure difference. Among them, the sub-graph (a) shows the flow rate improvement rate when the separation process is performed at 320 ° C, and the (b) sub-picture shows the flow rate improvement rate when the separation process is performed at 380 ° C.

In the sub-graph (a), the broken line 611 represents the improvement rate of the hydrogen flow rate when using the decompression unit and the non-decompression unit when the separation process is performed by passing gas example 1 under each hydrogen partial pressure difference. Similarly, the broken line 613 represents the improvement rate of the hydrogen flow rate when the gas is passed through the separation process of Example 2; the broken line 615 represents the improvement rate of the hydrogen flow rate when the gas is passed through the separation process of Example 3; Improvement rate of hydrogen flow during the process.

In the sub-graph (b), the broken line 621 represents the improvement rate of the hydrogen flow rate when using the decompression unit and the non-decompression unit when the separation process is performed by passing gas example 1 under each hydrogen partial pressure difference. Similarly, the broken line 623 represents the improvement rate of the hydrogen flow rate of the separation process in which the gas is passed in Example 2. The broken line 625 Table 3 shows the improvement rate of the hydrogen flow rate of the separation process in the case of introducing gas 3, and the broken line 627 represents the improvement rate of the hydrogen flow rate in the separation process of introducing the gas example 4.

According to Figure 6, it can be known that, because the improvement rates are all greater than 0%, regardless of the temperature of the separation process is 320 ° C or 380 ° C, when the pressure reduction unit is used to control the pressure on the permeate side, the flow rate of hydrogen in the mixed gas through the membrane element is uniform. Can be effectively promoted and has better penetration effect. Moreover, compared with the flow rate improvement rate of pure hydrogen, if the mixed gas contains other gases, the penetration effect of hydrogen through the membrane element can be further enhanced. Among them, carbon monoxide has the greatest benefit in increasing the flow of hydrogen in the mixed gas, followed by carbon dioxide, and even more nitrogen.

According to this, the mixed gas separation method and gas separation device of the present invention can effectively separate hydrogen from the mixed gas. Among them, when the mixed gas contains only hydrogen and another gas, the two kinds of gases can be effectively separated and collected by the separation method and the gas separation device of the mixed gas of the present invention. Secondly, if the pressure on the permeate side of the membrane element is less than 1 atm, the hydrogen in the mixed gas can penetrate the membrane element more effectively, and has better permeability properties.

In addition, when a decompression unit is configured to control the pressure on the permeate side, and the mixed gas contains gases other than hydrogen, these other gases can help increase the permeability coefficient of hydrogen permeating through the membrane element, thereby increasing its permeability coefficient. Among them, the benefit of carbon monoxide is greater than carbon dioxide, and the benefit of carbon dioxide is greater than nitrogen.

Although the present invention has been disclosed as above in the embodiments, it is not intended to limit the present invention, and any person having ordinary knowledge in the technical field to which the present invention belongs Experts, without departing from the spirit and scope of the present invention, can make various modifications and retouching. Therefore, the protection scope of the present invention shall be determined by the scope of the appended patent application.

Claims (3)

A method for promoting separation of a gas mixture, comprising: providing a mixed gas system consisting of hydrogen, and one or more of nitrogen, carbon monoxide, and carbon dioxide, wherein the content of the hydrogen is greater than or equal to 20 volume percent; The mixed gas is introduced into a separation tank of a gas separation device, wherein the separation tank includes a membrane separation unit and at least one heating unit, the membrane separation unit passes through the separation tank, and the membrane separation unit has a membrane element, a A closed end and an open end, the membrane element and the closed end are located in the separation tank, the open end is located outside the separation tank, the membrane element separates a high-pressure side and a permeate side, and the mixed gas is in the high-pressure side Has a hydrogen partial pressure, the at least one heating unit is disposed on an inner wall of the separation tank, and the at least one heating element covers the membrane element; and the pressure on the permeate side is reduced to less than 1 atm, so that the high pressure side A pressure difference between the hydrogen partial pressure and the pressure on the permeate side is 2 atm to 3 atm, so that the hydrogen gas passes through the membrane element and is permeated by the permeation. Flows, wherein when the hydrogen gas through the membrane elements, one element of the film to a temperature of 320 ℃ 380 ℃. The method for promoting separation of a gas mixture according to item 1 of the scope of the patent application, wherein the step of maintaining the pressure on the permeate side to less than 1 atm uses a vacuum pump. The method for promoting separation of a gas mixture according to item 1 of the scope of the patent application, wherein the thin film element comprises a palladium film.