Gas separation membrane module, its use and method for separating and recovering low carbon hydrocarbon mixture

Abstract

This invention relates to the field of low-carbon hydrocarbon separation and recovery, and discloses a gas separation membrane module and its application, as well as a method for separating and recovering low-carbon hydrocarbon mixed gas. The gas separation membrane module includes m gas-liquid separation devices and n membrane tubes arranged along the length of the gas separation membrane module. Each gas-liquid separation device is directly connected to a different membrane tube; m and n are independently selected from positive integers, and m ≤ n; each membrane tube includes an outer membrane tube and an inner membrane tube nested within the outer membrane tube; the inner membrane tube contains a membrane core for membrane separation and concentration of the feed gas to obtain permeate gas and a concentrated gas-liquid mixture; based on the volume of the inner membrane tube, the total volume of the membrane core is 10-80% of the volume of the inner membrane tube. This invention integrates multiple gas-liquid separation devices and membrane tubes, allowing low-carbon hydrocarbons in the feed gas to be liquefied and separated without external condensation, reducing energy consumption and improving hydrogen separation efficiency.

Description

Technical Field

[0001] This invention relates to the field of low-carbon hydrocarbon separation and recovery, specifically to a gas separation membrane module and its application, and a method for separating and recovering low-carbon hydrocarbon mixed gases. Background Technology

[0002] Products from petrochemical production processes generally need to be separated and purified in separation units. The separation of hydrogen and low-carbon hydrocarbons is particularly common. For example, hydrogenation tail gas, catalytic reforming tail gas, refinery dry gas, and propane dehydrogenation products all require separation, purification, and recovery of hydrogen and low-carbon hydrocarbons to achieve the goals of saving energy and improving economic efficiency.

[0003] Commonly used industrial technologies for the separation and recovery of low-carbon hydrocarbons include pressure swing adsorption (PSA), membrane separation, and condensation. Among these, membrane separation technology is considered one of the most promising separation technologies due to its advantages such as wide range of concentrations it can handle, high selectivity, good stability, environmental friendliness, and simple operation.

[0004] Currently, in membrane-based separation and recovery of low-carbon hydrocarbons, rubber-polymer gas membrane separation technology that allows low-carbon hydrocarbons to pass through is generally preferred. The membrane modules used in this method are typically traditional, stand-alone spiral wound or tubular membrane modules. Traditional membrane modules consist only of a membrane core and a membrane tube, such as sleeve-type gas separation membrane modules (CN 105597547A), spiral wound gas separation membrane modules (CN 215214908U), hollow fiber gas separation membrane modules (CN 206252989U and CN104703674A), and stacked gas separation membrane modules (CN 207520868U). However, existing membrane separation technologies still require downstream condensation to achieve liquefaction and collection of low-carbon hydrocarbons. The energy consumption of this type of membrane module separation process is higher than that of condensation technology, resulting in poor economic efficiency.

[0005] Therefore, in order to reduce the energy consumption of membrane-based low-carbon hydrocarbon recovery technology and improve its competitiveness and economy, it is urgent to develop a new low-energy-consumption low-carbon hydrocarbon membrane separation technology. Summary of the Invention

[0006] The purpose of this invention is to overcome the problems of high energy consumption, the need for additional condensation treatment, and high cost of existing membrane-based low-carbon hydrocarbon recovery technologies. This invention provides a gas separation membrane module and its application, as well as a method for separating and recovering low-carbon hydrocarbon mixed gases. By integrating a gas-liquid separation device downstream of the membrane retention side, this gas separation membrane module eliminates the need for additional condensation treatment, improves the hydrogen separation effect, increases the hydrogen content on the permeate side, and further enhances economic benefits.

[0007] To achieve the above objectives, the first aspect of the present invention provides a gas separation membrane assembly, the gas separation membrane assembly comprising m gas-liquid separation devices and n membrane tubes arranged along the length direction of the gas separation membrane assembly, wherein each gas-liquid separation device is directly connected to a different membrane tube; m and n are each independently selected from positive integers, and m≤n;

[0008] Each membrane tube includes an outer membrane tube and an inner membrane tube nested within the outer membrane tube; the inner membrane tube is provided with a membrane core for membrane separation and concentration of the feed gas to obtain permeate gas and a concentrated gas-liquid mixture;

[0009] Based on the volume of the inner membrane tube, the total volume of the membrane core is 10-80% of the volume of the inner membrane tube.

[0010] A second aspect of the present invention provides the application of the above-described gas separation membrane module in the separation and recovery of low-carbon hydrocarbons.

[0011] The third aspect of the present invention provides a method for separating and recovering a low-carbon hydrocarbon mixture, wherein, under separation conditions, the raw gas is passed into a gas separation membrane module for separation to obtain hydrogen and low-carbon hydrocarbons;

[0012] The raw material gas includes low-carbon hydrocarbons of C1-C5 and hydrogen.

[0013] The gas separation membrane assembly is the gas separation membrane assembly described in the first aspect.

[0014] The beneficial effects obtained by the present invention through the above technical solution are as follows:

[0015] 1. The gas separation membrane module provided by this invention enables the liquefaction and separation of low-carbon hydrocarbons in the feed gas without the need for external condensation, thereby reducing energy consumption. If the feed gas enters the membrane module under pressure, after being depressurized in the demister, the pressurized low-carbon hydrocarbons are converted into atmospheric-pressure low-carbon hydrocarbons, which are easier to liquefy, thereby improving the hydrogen separation effect and increasing the hydrogen content on the permeate side.

[0016] 2. The gas separation membrane module provided by the present invention adopts a split design, which makes it more convenient to perform maintenance, disassembly and cleaning, and replacement of parts of the membrane module, thereby reducing maintenance time and cost.

[0017] 3. The gas separation membrane module provided by the present invention can realize the integrated assembly of multiple gas-liquid separation devices and membrane tubes, making the equipment more compact and smaller in size. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the gas separation membrane assembly in Example 1 (m=1, n=1);

[0019] Figure 2This is a schematic diagram of the gas separation membrane assembly in Example 2 (m=1, n=1);

[0020] Figure 3 This is a schematic diagram of the gas separation membrane assembly in Example 3 (m=3, n=3);

[0021] Figure 4 This is a schematic diagram of the gas separation membrane assembly in Example 4 (m=3, n=3);

[0022] Figure 5 This is a schematic diagram of the gas separation membrane assembly in Example 5 (m=3, n=3).

[0023] Explanation of reference numerals in the attached figures

[0024] 1. Air inlet 2. Float 3. Liquid outlet

[0025] 4. Gas-liquid separator 5. Demister 6. Membrane element

[0026] 7. Inner membrane tube; 8. Permeation side port; 9. Retention side port

[0027] 10. Retaining gas channel; 11. Outer membrane tube; 12. Permeation gas channel

[0028] 13. Retention air passage tube; 14. Membrane core inlet; 15. Membrane core outlet.

[0029] 16 Gas Separation Membrane Module Detailed Implementation

[0030] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0031] In the description of this invention, it should be understood that the terms "length," "upper," "lower," "vertical," "horizontal," "top," and "bottom," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. In addition, "inner" and "outer" refer to the inner and outer contours relative to the outline of each component itself.

[0032] The first aspect of the present invention provides a gas separation membrane assembly, the gas separation membrane assembly comprising m gas-liquid separation devices and n membrane tubes arranged along the length direction of the gas separation membrane assembly, wherein each gas-liquid separation device is directly connected to a different membrane tube; m and n are each independently selected from positive integers, and m≤n;

[0033] Each membrane tube includes an outer membrane tube and an inner membrane tube nested within the outer membrane tube. The inner membrane tube contains a membrane core for membrane separation and concentration of the feed gas, yielding a permeate gas and a concentrated gas-liquid mixture. It is understood that under certain temperature conditions, liquefaction can be achieved when the pressure reaches the saturated vapor pressure of the mixed gas during the concentration process. In this invention, the higher the hydrogen separation efficiency, the lower the hydrogen content in the separated mixed gas, and the easier the mixed gas is to liquefy.

[0034] Based on the volume of the inner membrane tube, the total volume of the membrane core is 10-80% of the volume of the inner membrane tube.

[0035] According to the present invention, the gas separation membrane module is suitable for membrane separation and recovery of organic gases, especially for the separation and recovery of low-carbon hydrocarbons in low-carbon hydrocarbon mixtures. The low-carbon hydrocarbon mixture originates from hydrogenation tail gas, catalytic reforming tail gas, refinery dry gas, and propane dehydrogenation products, and generally includes hydrogen and low-carbon hydrocarbons. In existing technologies, downstream external condensation is required after membrane separation to achieve liquefaction and collection of low-carbon hydrocarbons, significantly increasing energy consumption in the separation process. In the present invention, the gas separation membrane module, through the integrated assembly of multiple gas-liquid separators and membrane tubes, enables the liquefaction and separation of low-carbon hydrocarbons without the need for external condensation, improving hydrogen separation efficiency and significantly reducing energy consumption.

[0036] According to the present invention, it is understood that after the membrane core is filled in the inner membrane tube, there are gaps in the inner membrane tube, providing a permeate gas channel for the permeate gas passing through the membrane core. Preferably, based on the volume of the inner membrane tube, the total volume of the membrane core is 30-60% of the volume of the inner membrane tube. In the above preferred case, it is beneficial to further improve the separation efficiency.

[0037] In this invention, the m gas-liquid separation devices are directly connected to n membrane tubes. The number of gas-liquid separators and membrane tubes can be selected according to actual production needs. Preferably, m = 2-10 and n = 2-10. For example, the gas separation membrane assembly can consist of one gas-liquid separator and one membrane tube, one gas-liquid separator and N membrane tubes, or N gas-liquid separators and N membrane tubes.

[0038] In this invention, preferably, the gas-liquid separation device includes a demister and a gas-liquid separator.

[0039] In this invention, preferably, the demister is connected to the gas-liquid separator and the membrane core respectively, and is used to further liquefy the gas-liquid mixture obtained by separation through the membrane core, and then send it into the gas-liquid separator; in the above preferred case, the feed gas containing low-carbon hydrocarbons enters the membrane module under pressure, and after being depressurized in the demister, the pressurized low-carbon hydrocarbons are converted into atmospheric low-carbon hydrocarbons, which are easier to liquefy.

[0040] In this invention, there are no special requirements for the dimensions of the demister and the gas-liquid separator, as long as the above-described combination of devices can be achieved. Preferably, the diameter of the demister is equal to the diameter of the gas-liquid separator.

[0041] In this invention, preferably, the demister is provided with perforated plates at the top and bottom; preferably, the porosity of the perforated plates is 5-80%, more preferably 10-60%. In the above preferred embodiments, it helps to achieve uniform distribution of gas and liquid.

[0042] In this invention, preferably, each gas-liquid separator is provided with a liquid outlet at the bottom for discharging liquefied low-carbon hydrocarbons from the gas separation membrane assembly.

[0043] In this invention, preferably, the liquid outlet is connected to the liquid outlet pipeline, and a check valve is provided on the liquid outlet pipeline to prevent liquid from back-mixing into the gas-liquid separator.

[0044] In this invention, preferably, the liquid outlet is provided with a float ball, and preferably, the float ball is fixed above the liquid outlet by a hollow cover to seal the liquid outlet and thus control the liquid output.

[0045] In this invention, preferably, the gas separation membrane assembly is provided with an inlet, a retention side port, and at least one permeation side port. The feed gas enters the gas separation membrane assembly through the inlet, while non-hydrocarbon gases such as hydrogen preferentially permeate through the membrane core and exit the gas separation membrane assembly through the permeation side port. When low-carbon hydrocarbons reach saturation in the membrane tube, the liquid-phase low-carbon hydrocarbons are collected in a gas-liquid separator, and the retained gas-phase low-carbon hydrocarbons are returned to the inlet through the retention side port or enter the next stage gas separation membrane assembly for further separation.

[0046] According to the present invention, preferably, the ratio of the outer diameter of the inner membrane tube to the inner diameter of the outer membrane tube is 0.2-1:1.

[0047] According to a preferred embodiment of the present invention, n=1, the air inlet is located at the top of the membrane tube, or the air inlet is located between the gas-liquid separator and the demister. In the above cases, the gas separation membrane assembly can be placed vertically or horizontally.

[0048] Preferably, the permeate side port is disposed on the top and / or sidewall of the membrane tube for discharging permeate gas through the membrane core into the gas separation membrane assembly.

[0049] Preferably, the interception port is located at the bottom and / or top of the membrane tube, for returning unliquefied gas to the inlet or sending it to the next stage gas separation membrane assembly.

[0050] Preferably, the interception side opening is located at the top of the membrane tube, the outer diameter of the inner membrane tube is smaller than the inner diameter of its outer membrane tube, and the gap between the inner and outer membrane tubes forms an interception gas channel.

[0051] According to the present invention, preferably, the ratio of the outer diameter of the inner membrane tube to the inner diameter of the outer membrane tube is 0.4-0.9:1.

[0052] Preferably, the interception port is located at the bottom of the membrane tube, and the outer diameter of the inner membrane tube is equal to the inner diameter of the outer membrane tube.

[0053] According to another preferred embodiment of the present invention, n>1, the gas separation membrane assembly is placed horizontally.

[0054] Preferably, the air inlet is located at the top of the first membrane tube for introducing the raw material gas into the gas separation membrane assembly.

[0055] Preferably, the permeate side port is located on the top of the first membrane tube and / or on the sidewall of each membrane tube, for discharging the permeate gas through the membrane core into the gas separation membrane assembly.

[0056] Preferably, the interception port is located at the bottom of the nth membrane tube and / or the top of the 1st membrane tube, for returning unliquefied gas to the inlet or sending it to the next stage gas separation membrane assembly.

[0057] According to a preferred embodiment of the present invention, the air inlet is disposed at the top of the first membrane tube, and the interception side port is disposed at the top of the first membrane tube, wherein the outer diameter of the inner membrane tube in each membrane tube is smaller than the inner diameter of its outer membrane tube, and the gap between the inner membrane tube and the outer membrane tube forms an interception gas channel for the intercepted low-carbon hydrocarbons to pass through.

[0058] According to the present invention, preferably, the ratio of the outer diameter of the inner membrane tube to the inner diameter of the outer membrane tube is 0.4-0.9:1. In this preferred embodiment, it is beneficial to improve the separation efficiency.

[0059] According to the present invention, preferably, two adjacent membrane tubes are connected by a tethering air channel tube. The tethering air channel tube is a hollow tube, and there are no special requirements for the size and material of the tethering air channel tube, as long as it is ensured that the membrane cores are not connected to the tethering side channel.

[0060] According to another preferred embodiment of the present invention, the air inlet is located at the top of the first membrane tube, and the intercepting side outlet is located at the bottom of the nth membrane tube, wherein the outer diameter of the inner membrane tube in each membrane tube is equal to the inner diameter of its outer membrane tube. It is understood that when the outer diameter of the inner membrane tube in each membrane tube is equal to the inner diameter of its outer membrane tube, there is no gap between the inner and outer membrane tubes.

[0061] According to the present invention, there are no special requirements for the connection method of each device in the gas separation membrane assembly. Preferably, the gas-liquid separation device is connected to the bottom of the membrane tube through a flange connection and / or a threaded connection.

[0062] In this invention, the material selection range for the gas-liquid separation device is relatively wide, and it can be selected according to the actual needs of production conditions. Preferably, the material of the gas-liquid separation device is metal, such as 316 stainless steel.

[0063] In this invention, the specific type of membrane core can be selected according to the type of feed gas, and can be selected from conventional separation membranes in the art. For example, at least one of organic separation membranes, inorganic separation membranes, and organic-inorganic hybrid separation membranes. Preferably, when the feed gas is a mixture of low-carbon hydrocarbons and hydrogen, the membrane core includes a hydrogen-permeable organic-inorganic hybrid membrane.

[0064] A second aspect of the present invention provides the application of the above-described gas separation membrane module in the separation and recovery of low-carbon hydrocarbons.

[0065] A third aspect of the present invention provides a method for separating and recovering a low-carbon hydrocarbon mixture, wherein, under separation conditions, the raw material gas is passed into a gas separation membrane module for separation;

[0066] The gas separation membrane assembly is the gas separation membrane assembly described above.

[0067] In this invention, preferably, the raw material gas includes low-carbon hydrocarbons of C1-C5 and hydrogen, and preferably, the hydrogen content in the raw material gas is 20-60 vol%.

[0068] According to the present invention, the above-described method for separating and recovering low-carbon hydrocarbon mixtures can achieve liquefaction and recovery of low-carbon hydrocarbons without the need for external condensation, significantly reducing separation energy consumption. Simultaneously, it can improve separation efficiency, achieving a hydrogen concentration of over 70 vol% in the permeate-side gas, thus realizing highly efficient separation of hydrogen and low-carbon hydrocarbons. For example, when m = 1 and n = 1, the hydrogen content in the feed gas can be increased from 43.8 vol% to over 70 vol%; when m = 3 and n = 3, the hydrogen content in the feed gas can be increased from 43.8 vol% to over 90 vol%.

[0069] According to the present invention, preferably, the separation conditions include: membrane separation temperature of 10-150℃, gas-liquid separation temperature of 2-50℃, membrane pressure difference of 0.1-5MPa, and feed gas flow rate of 1-500mL / min.

[0070] More preferably, the separation conditions include: membrane separation temperature of 20-100℃, gas-liquid separation temperature of 10-35℃, membrane pressure difference of 0.5-3MPa, and feed gas flow rate of 10-200mL / min.

[0071] The present invention will be described in detail below through embodiments.

[0072] The composition of the raw gas used in the following embodiments is shown in Table 1.

[0073] Table 1

[0074]

[0075]

[0076] Example 1

[0077] Gas separation membrane modules such as Figure 1 As shown, the gas separation membrane module 16 includes one membrane tube and one gas-liquid separator (m=1, n=1). The gas-liquid separation device is installed at the bottom of the membrane tube and includes a gas-liquid separator 4 and a demister 5. The membrane tube, demister 5, and gas-liquid separator 4 are connected in sequence. The membrane tube includes an outer membrane tube 11 and an inner membrane tube 7. The outer diameter of the inner membrane tube is equal to the inner diameter of the outer membrane tube. The inner membrane tube is filled with a membrane core, which is an organic separation membrane (commercially purchased, brand name UBE hydrogen separation membrane). The total volume of the membrane core is 50% of the volume of the inner membrane tube, and the voids in the inner membrane tube form a permeate channel 12. The inlet 1 is installed above the gas-liquid separator 4 and below the demister 5. The demister is equipped with perforated plates at the top and bottom, and the porosity of the perforated plates is 40%. The inlet 14 of the membrane core is connected to the gas-liquid separation device. The permeate side port 8 is connected to the permeate channel 12.

[0078] The above-mentioned gas separation membrane module was used for testing. The feed gas was introduced into the gas-liquid separator 4 through the inlet 1 below the gas separation membrane module 16. Under the action of the demister 5, a portion of the low-carbon hydrocarbons were liquefied and separated, and collected in the gas-liquid separator 4. When a certain amount of liquid was collected, the float 2 floated up under buoyancy, and the liquid flowed out through the outlet 3 and into the collection tank. The unliquefied low-carbon hydrocarbons rose and entered the membrane core 6. Non-hydrocarbon gases such as hydrogen preferentially permeated through the membrane core 6, entered the permeate gas channel 12, and then exited the membrane module through the permeate side port 8. During the rising and separation of low-carbon hydrocarbons in the membrane core 6, when saturation was reached, the liquid phase low-carbon hydrocarbons flowed along the membrane core 6 into the gas-liquid separator 4 for collection. The retained gaseous low-carbon hydrocarbons were returned to the oil storage tank through the retention side port 9.

[0079] The separation conditions included a membrane separation section temperature of 50℃, a gas-liquid separator section temperature of 25℃, a permeate pressure differential of 1.2MPa, and a feed gas rate of 80mL / min. Products were collected from the retardation side (port 9) and the permeate side (port 8), respectively. The composition of the products on the permeate and retardation sides is shown in Table 2.

[0080] Example 2

[0081] Gas separation membrane modules such as Figure 2 As shown, the gas separation membrane module 16 includes one membrane tube and one gas-liquid separator (m=1, n=1). The gas-liquid separator is installed at the bottom of the membrane tube and includes a gas-liquid separator 4 and a demister 5. The demister has orifice plates at its top and bottom with a porosity of 40%. The membrane tube, demister 5, and gas-liquid separator 4 are connected in sequence. The membrane tube includes an outer membrane tube 11 and an inner membrane tube 7. The ratio of the outer diameter of the inner membrane tube to the inner diameter of the outer membrane tube is 0.7:1, with a gap in the middle for a gas trapping channel 10. The inner membrane tube is filled with a membrane core 6, which is an organic separation membrane (commercially purchased, brand name UBE hydrogen separation membrane). The total volume of the membrane core is 50% of the volume of the inner membrane tube, and the gap in the inner membrane tube forms a permeate channel 12. The inlet 1 is located at the top center of the gas separation membrane module 16, and the permeate side port 8 is located at the top of the membrane tube. The trapping side port 9 is located at the top of the membrane tube. The entrapment gas channel 10 is connected to the entrapment side port 9. The permeate gas channel 12 is connected to the permeate port 8. The membrane element inlet 14 is connected to the air inlet 1, and the membrane element outlet is connected to the gas-liquid separator 4. The entrapment gas channel 10 is connected to the gas-liquid separator 4.

[0082] The above-mentioned gas separation membrane module was used for testing. The feed gas entered the membrane core 6 through the inlet 1 at the top of the gas separation membrane module 16. Non-hydrocarbon gases such as hydrogen preferentially permeate through the membrane core 6, enter the permeate gas channel 12, and then exit the membrane module through the permeate side port 8. The retained low-carbon hydrocarbons were concentrated, liquefied, and flowed down the membrane core 6 into the gas-liquid separator 4. Unliquefied gaseous low-carbon hydrocarbons also entered the gas-liquid separator 4, where a portion was further liquefied by the demister 5 and collected in the gas-liquid separator 4. The remaining unliquefied gaseous low-carbon hydrocarbons passed through the retained gas channel 10 and were returned to the oil storage tank through the retained side port 9. When a certain amount of liquid was collected, the float 2 rose under buoyancy, and the liquid flowed out through the outlet 3 and into the collection tank.

[0083] The separation conditions included a membrane separation section temperature of 50℃, a gas-liquid separator section temperature of 25℃, a permeate pressure differential of 1.2MPa, and a feed gas rate of 80mL / min. Products were collected from the retardation side (port 9) and the permeate side (port 8), respectively. The composition of the products on the permeate and retardation sides is shown in Table 2.

[0084] Comparative Example 1

[0085] The gas separation membrane assembly of Example 2 is used, except that the gas separation membrane assembly does not include a gas-liquid separator and a demister.

[0086] The membrane separation section was set at a temperature of 50°C, a permeabilization pressure difference of 1.2 MPa, and a feed gas rate of 80 mL / min. Products were collected from both the retardation and permeation sides. The product compositions on the permeation and retardation sides are shown in Table 2. Compared to Example 2, the hydrogen concentration on the permeation side decreased significantly.

[0087] Comparative Example 2

[0088] The gas separation membrane module in Comparative Example 1 is used, but the difference is that the raw gas first passes through an external condenser (condensation temperature 4℃-5℃) to remove some of the liquefied substances in the raw gas, and then enters the gas separation membrane module proposed in Comparative Example 1.

[0089] The products from the tampered side and the permeated side were collected separately. The product composition of the permeated side and the tampered side is shown in Table 2. Compared with Comparative Example 1, the hydrogen concentration on the permeated side was increased but still much lower than the hydrogen concentration on the permeated side in Example 2.

[0090] Example 3

[0091] Gas separation membrane modules such as Figure 3 As shown. The gas separation membrane module 16 includes three membrane tubes and three gas-liquid separators (m=3, n=3). The gas separation membrane module 16 is installed horizontally, and the bottom of each membrane tube is connected to the gas-liquid separation device. The gas-liquid separation device includes a gas-liquid separator 4 and a demister 5. The demister has orifice plates at the top and bottom, with a porosity of 40%. The demister 5 is perpendicular to the inner membrane tube, and the gas-liquid separator 4 is installed below the demister 5. The membrane tubes include an outer membrane tube 11 and an inner membrane tube 7. The ratio of the outer diameter of the inner membrane tube to the inner diameter of the outer membrane tube is 0.7:1, with a gap in the middle as a gas interception channel 10. The inner membrane tube is filled with a membrane core 6, which is an organic separation membrane (commercially purchased, brand name UBE hydrogen separation membrane). The total volume of the membrane core is 50% of the volume of the inner membrane tube, and the voids in the inner membrane tube form a permeate channel 12. The tack gas channel between adjacent membrane tubes is connected to membrane element 6 and the gas-liquid separator, sending the tack gas into the next stage membrane element for further separation. The tack gas channel 13 at the end is connected to the outer membrane tube, connecting the tack gas channels 10 in each membrane tube, and finally connecting to the tack side port 9, allowing the final tack gas to return to the tack side port 9. The permeate gas channel 12 is connected to the permeate port 8, which is located at the top of the membrane tube. The inlet of the first membrane element is connected to the inlet 1, and the outlet of the membrane element is connected to the inlet of the adjacent membrane element.

[0092] The gas separation membrane module proposed in Example 3 was used in the experiment. The feed gas enters the membrane element 6 through the inlet 1 at the top of the gas separation membrane module 16. Non-hydrocarbon gases such as hydrogen preferentially permeate through the membrane element 6, enter the permeate gas channel 12, and then exit the membrane module through the permeate side port 8. The retained low-carbon hydrocarbons are concentrated, liquefied, and flow into the gas-liquid separator 4 along the membrane element 6. Unliquefied low-carbon hydrocarbons in the gas phase are further liquefied by the demister 5, and collected in the gas-liquid separator 4. The remaining unliquefied low-carbon hydrocarbons in the gas phase enter the next membrane element 6 for further concentration, separation, and collection. When the low-carbon hydrocarbons exit from the outlet of the last membrane element, they are liquefied and collected by the demister 5. The remaining unliquefied low-carbon hydrocarbons in the gas phase pass through the intercepted gas channel pipe 13 and the intercepted gas channel 10, and are finally returned to the oil storage tank or enter the next gas separation membrane module 16 for further separation through the intercepted side port 9. When a certain amount of liquid is collected, the float 2 floats up under the action of buoyancy, and the liquid flows out through the outlet 3 and into the collection tank.

[0093] The gas separation membrane module proposed in Example 3 was used in the experiment. The separation conditions included: membrane separation section temperature 50°C, gas-liquid separator section temperature 25°C, permeate pressure differential 1.2 MPa, and feed gas flow rate 80 mL / min. The products from the retrieval side port 9 and the permeate side port 8 were collected separately, and the product compositions of the permeate side and the retrieval side are shown in Table 2.

[0094] Example 4

[0095] Gas separation membrane modules such as Figure 4 As shown. The gas separation membrane module 16 includes three membrane tubes and three gas-liquid separators (m=3, n=3). The gas separation membrane module 16 is installed horizontally, and the bottom of each membrane tube is connected to the gas-liquid separation device. The gas-liquid separation device includes a gas-liquid separator 4 and a demister 5. The demister has orifice plates at the top and bottom, with a porosity of 40%. The demister 5 is perpendicular to the inner membrane tube, and the gas-liquid separator 4 is installed below the demister 5. The membrane tubes include an outer membrane tube 11 and an inner membrane tube 7. The ratio of the outer diameter of the inner membrane tube to the inner diameter of the outer membrane tube is 0.7:1, with a gap in the middle as a gas interception channel 10. The inner membrane tube is filled with a membrane core 6, which is an organic separation membrane (commercially purchased, brand name UBE hydrogen separation membrane). The total volume of the membrane core is 50% of the volume of the inner membrane tube, and the voids in the inner membrane tube form a permeate channel 12. The tack gas channel between adjacent membrane tubes is connected to membrane element 6 and the gas-liquid separator, sending the tack gas into the next stage membrane element for further separation. The tack gas channel 13 at the end is connected to the outer membrane tube, connecting the tack gas channels 10 in each membrane tube, and finally connecting to the tack side port 9, allowing the tack gas to return to the tack side port 9. The permeate gas channel 12 is connected to the permeate port 8, which is located on the upper part of the side of each membrane tube. The inlet of the first membrane element is connected to the inlet 1, and the outlet of the membrane element is connected to the inlet of the adjacent membrane element.

[0096] The gas separation membrane module proposed in Example 4 was used in the experiment. The feed gas enters the membrane element 6 through the inlet 1 at the top of the gas separation membrane module 16. Non-hydrocarbon gases such as hydrogen preferentially permeate through the membrane element 6, enter the permeate gas channel 12, and then exit the membrane module through the permeate side port 8. The retained low-carbon hydrocarbons are concentrated, liquefied, and flow into the gas-liquid separator 4 along the membrane element 6. Unliquefied low-carbon hydrocarbons in the gas phase are further liquefied by the demister 5, and collected in the gas-liquid separator 4. The remaining unliquefied low-carbon hydrocarbons in the gas phase enter the next membrane element 6 for further concentration, separation, and collection. When the low-carbon hydrocarbons exit from the outlet of the last membrane element, they are liquefied and collected by the demister 5. The remaining unliquefied low-carbon hydrocarbons in the gas phase pass through the intercepted gas channel pipe 13 and the intercepted gas channel 10, and are finally returned to the oil storage tank or enter the next gas separation membrane module 16 for further separation through the intercepted side port 9. When a certain amount of liquid is collected, the float 2 floats up under the action of buoyancy, and the liquid flows out through the outlet 3 and into the collection tank.

[0097] The separation conditions included: membrane separation section temperature 50℃, gas-liquid separator section temperature 25℃, permeabilization pressure difference 1.2MPa, and feed gas rate 80mL / min. Products were collected from the retardation side (port 9) and permeation side (port 8), and the product compositions for the permeation and retardation sides are shown in Table 2.

[0098] Example 5

[0099] Gas separation membrane modules such as Figure 5 As shown. The gas separation membrane module 16 includes three membrane tubes and three gas-liquid separators (m=3, n=3). The gas separation membrane module 16 is installed horizontally, and the bottom of each membrane tube is connected to the gas-liquid separation device. The gas-liquid separation device includes a gas-liquid separator 4 and a demister 5. The demister has orifice plates at the top and bottom, with a porosity of 40%. The demister 5 is perpendicular to the inner membrane tube, and the gas-liquid separator 4 is installed below the demister 5. The membrane tubes include an outer membrane tube 11 and an inner membrane tube 7. The outer diameter of the inner membrane tube is equal to the inner diameter of the outer membrane tube. The inner membrane tube is filled with a membrane core 6, which is an organic separation membrane (commercially purchased, brand name UBE hydrogen separation membrane). The total volume of the membrane core is 50% of the volume of the inner membrane tube, and the voids in the inner membrane tube form permeate channels 12. The gas inlet 1 of the gas separation membrane module 16 is installed on one side of the gas separation membrane module 16, the other side is installed with a trapping side port 9, and the side of the gas separation membrane module 16 is installed with a permeate side port 8. The outer diameter of the inner membrane tube is equal to the inner diameter of the outer membrane tube. The inlet of membrane element 6 is connected to the air inlet 1, the outlet of membrane element 6 is connected to the inlet of the next membrane element, and the outlet of the last membrane element 6 is connected to the retention side port 9. The permeate passage 12 of each outer membrane tube 11 is connected to the permeate side port 8.

[0100] The gas separation membrane module proposed in Example 5 was used in the experiment. The feed gas was introduced into the membrane element 6 through the inlet 1 at the top of the gas separation membrane module 16. Non-hydrocarbon gases such as hydrogen preferentially permeate through the membrane element 6, enter the permeate channel 12, and then exit the membrane module through the permeate side port 8. The retained low-carbon hydrocarbons were concentrated, liquefied, and flowed into the gas-liquid separator 4 along the membrane element 6. Unliquefied low-carbon hydrocarbons in the gas phase were further liquefied by the demister 5 and collected in the gas-liquid separator 4. The remaining unliquefied low-carbon hydrocarbons entered the next membrane element 6 for further concentration, separation, and collection. When the low-carbon hydrocarbons exited from the outlet of the last membrane element, they were liquefied and collected by the demister 5. The remaining unliquefied low-carbon hydrocarbons were returned to the oil storage tank through the retention side port 9 or entered the next gas separation membrane module 16 for further separation. When a certain amount of liquid was collected, the float 2 floated under buoyancy, and the liquid flowed out through the outlet 3 and into the collection tank.

[0101] The separation conditions included: membrane separation section temperature 50℃, gas-liquid separator section temperature 25℃, permeabilization pressure difference 1.2MPa, and feed gas rate 80mL / min. Products were collected from the retardation side (port 9) and permeation side (port 8), and the product compositions for the permeation and retardation sides are shown in Table 2.

[0102] Example 6

[0103] The method is the same as in Example 4, except that the gas separation membrane assembly does not include a demister. The separation conditions include: membrane separation section temperature 50°C, gas-liquid separator section temperature 25°C, permeate pressure differential 1.2 MPa, and feed gas rate 80 mL / min. Products from the retrieval side port 9 and the permeate side port 8 are collected separately; the composition of the products on the permeate and retrieval sides is shown in Table 2.

[0104] Table 2

[0105]

[0106] As can be seen from the results in Table 2, the gas separation membrane assembly of the present invention can significantly improve the liquefaction rate of supersaturated low-carbon hydrocarbons through the integrated gas-liquid separator, and achieve partial liquefaction of low-carbon hydrocarbons without the need for external condensation, thereby improving the hydrogen separation effect, increasing the hydrogen content on the permeate side, and facilitating pressure release during the oil filling process of the storage tank.

[0107] The preferred embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combinations of various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. A gas separation membrane module, characterized in that, The gas separation membrane module includes m gas-liquid separation devices and n membrane tubes arranged along the length of the gas separation membrane module, wherein each gas-liquid separation device is directly connected to a different membrane tube; m and n are each independently selected from positive integers, and m≤n, m=2-20, n=2-20; Each membrane tube includes an outer membrane tube and an inner membrane tube nested within the outer membrane tube; the inner membrane tube is provided with a membrane core for membrane separation and concentration of the feed gas to obtain permeate gas and a concentrated gas-liquid mixture; Based on the volume of the inner membrane tube, the total volume of the membrane core is 10-80% of the volume of the inner membrane tube; The gas-liquid separation device includes a demister and a gas-liquid separator. The demister is connected to both the gas-liquid separator and the membrane core, and is used to further liquefy the gas-liquid mixture from the membrane core before sending it into the gas-liquid separator.

2. The gas separation membrane module according to claim 1, wherein, m=2-10, n=2-10.

3. The gas separation membrane assembly according to claim 1 or 2, wherein, The diameter of the demister is equal to the diameter of the gas-liquid separator.

4. The gas separation membrane assembly according to claim 1 or 2, wherein, The demister is equipped with perforated plates at the top and bottom.

5. The gas separation membrane assembly according to claim 4, wherein, The porosity of the perforated plate is 5-80%.

6. The gas separation membrane assembly according to claim 1 or 2, wherein, Each gas-liquid separator has a liquid outlet at the bottom.

7. The gas separation membrane module according to claim 6, wherein, The liquid outlet is connected to the liquid outlet pipeline, and a check valve is installed on the liquid outlet pipeline.

8. The gas separation membrane module according to claim 6, wherein, The liquid outlet is equipped with a float.

9. The gas separation membrane module according to claim 8, wherein, The float is fixed above the liquid outlet by a hollow cover to seal the liquid outlet and thus control the liquid output.

10. The gas separation membrane assembly according to claim 6, wherein, The gas separation membrane assembly is provided with an air inlet, a tampering side port and at least one permeation side port.

11. The gas separation membrane assembly according to claim 10, wherein, The gas separation membrane assembly is placed horizontally.

12. The gas separation membrane module according to claim 10, wherein, The air inlet is located at the top of the first membrane tube and is used to introduce the raw material gas into the gas separation membrane assembly.

13. The gas separation membrane assembly according to claim 10, wherein, The permeate side port is located on the top of the first membrane tube and / or on the side wall of each membrane tube, for discharging the permeate gas through the membrane core into the gas separation membrane assembly.

14. The gas separation membrane assembly according to claim 10, wherein, The interception port is located at the bottom of the nth membrane tube and / or the top of the 1st membrane tube, and is used to return unliquefied gas to the inlet or send it to the next stage gas separation membrane module.

15. The gas separation membrane assembly according to claim 14, wherein, The interception side opening is located at the top of the first membrane tube, wherein the outer diameter of the inner membrane tube in each membrane tube is smaller than the inner diameter of its outer membrane tube, and the gap between the inner membrane tube and the outer membrane tube forms an interception gas channel.

16. The gas separation membrane module according to claim 15, wherein, The ratio of the outer diameter of the inner membrane tube to the inner diameter of the outer membrane tube is 0.2-0.9:

1.

17. The gas separation membrane assembly according to claim 15, wherein, Two adjacent membrane tubes are connected by a truncation air channel tube.

18. The gas separation membrane assembly according to claim 14, wherein, The severance port is located at the bottom of the nth membrane tube, wherein the outer diameter of the inner membrane tube in each membrane tube is equal to the inner diameter of its outer membrane tube.

19. The gas separation membrane assembly according to claim 1 or 2, wherein, The gas-liquid separation device is connected to the bottom of the membrane tube via a flange connection and / or a threaded connection.

20. The gas separation membrane assembly according to claim 1 or 2, wherein, The gas-liquid separation device is made of metal.

21. The gas separation membrane assembly according to claim 1 or 2, wherein, The membrane core is selected from at least one of organic separation membranes, inorganic separation membranes, and organic-inorganic hybrid separation membranes.

22. The application of the gas separation membrane module according to any one of claims 1-21 in the separation and recovery of low-carbon hydrocarbons.

23. A method for separating and recovering a low-carbon hydrocarbon mixture, characterized in that, Under separation conditions, the feed gas is passed into the gas separation membrane module according to any one of claims 1-21 for separation to obtain hydrogen and low-carbon hydrocarbons; The feed gas includes low-carbon hydrocarbons of C1-C5 and hydrogen.

24. The method according to claim 23, wherein, The hydrogen content in the raw material gas is 20-60 vol.

25. The gas separation membrane assembly according to claim 23, wherein, The separation conditions include: membrane separation temperature of 10-150℃, gas-liquid separation temperature of 2-50℃, membrane pressure difference of 0.1-5MPa, and feed gas flow rate of 1-500mL / min.

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