Mixed pentane separation membrane performance test system and mixed pentane separation membrane performance test method

Abstract

The invention provides a mixed pentane separation membrane performance test system and a mixed pentane separation membrane performance test method. The performance test system for the mixed pentane separation membrane comprises a feeding unit, a vaporization unit, a membrane test unit and a component detection unit which are communicated in sequence, and can effectively ensure that a feed liquid state at a membrane feeding side is a steam state, so that the damage of an unvaporized liquid pentane feed liquid to the structure of the separation membrane is avoided.

Description

Technical Field

[0001] This invention relates to a mixed pentane separation membrane performance testing system and a mixed pentane separation membrane performance testing method, belonging to the field of mixed pentane separation membrane separation. Background Technology

[0002] Mixed pentanes have a wide range of applications. They can be used as a common organic solvent in cleaning, extraction and purification processes; as a refrigerant in refrigeration equipment such as CFC-free refrigerators and freezers and air conditioning systems; and as a foaming agent for polyurethane and polystyrene foams.

[0003] For mixed pentane systems, n-pentane has a boiling point of 36.1℃, isopentane has a boiling point of 27.8℃, and cyclopentane has a boiling point of 49.2℃. Their physical parameters are similar, and using traditional distillation processes to separate mixed pentanes has the disadvantage of high energy consumption. Therefore, many researchers have shifted their separation methods to membrane separation technology to achieve energy saving and consumption reduction.

[0004] Membrane separation technology mainly involves the purification and separation of n-pentane, isopentane, and cyclopentane using separation membranes. Currently, there are many devices available for testing the performance of separation membranes, but few are specifically designed for testing pentane systems. Furthermore, existing devices suffer from the following problems during operation: Firstly, mixed pentanes are liquid at room temperature, and liquid feed easily leads to contamination of the membrane material itself (damaging the membrane structure), resulting in a significant reduction in the membrane flux and separation selectivity obtained in the test. Secondly, the feed side and permeate side are respectively bubbled with a third component (such as nitrogen, helium, or argon) to introduce the feed liquid into the membrane feed side and purge the permeate side with a third component (such as nitrogen, helium, or argon) to introduce interfering components into the gas chromatography. Therefore, it is necessary to provide a new mixed pentane separation membrane performance testing system to improve the above-mentioned problems. Summary of the Invention

[0005] To address the aforementioned technical problems, the present invention aims to provide a mixed pentane separation membrane performance testing system and a mixed pentane separation membrane performance testing method, which can effectively prevent the separation membrane itself from being damaged.

[0006] To achieve the above objectives, the present invention provides a mixed pentane separation membrane performance testing system, comprising a feed unit, a vaporization unit, a membrane testing unit, and a component detection unit connected in sequence; the feed unit includes a temperature-controlled feed tank for storing mixed pentane; the vaporization unit includes a first heating device and a heating tube and a buffer tank connected in sequence within the cavity of the first heating device, the feed inlet of the heating tube being connected to the outlet of the temperature-controlled feed tank; the membrane testing unit includes a second heating device and a membrane testing assembly placed within the cavity of the second heating device, the feed inlet of the membrane testing assembly being connected to the outlet of the buffer tank; the component detection unit includes a gas chromatograph, the gas chromatograph and the permeate-side outlet of the membrane testing assembly being connected.

[0007] This invention incorporates a vaporization unit between the feeding unit and the membrane testing unit, allowing the liquid mixed pentane to vaporize before entering the membrane testing assembly. This avoids the problem of liquid material contaminating the separation membrane and damaging its structure. It is worth noting that this invention does not simply convert the mixed pentane from a liquid to a vapor state; more importantly, it ensures that the mixed pentane entering the membrane testing assembly is in a vapor state and maintains stable pressure within the membrane testing assembly.

[0008] This invention incorporates a buffer tank between the heating tube and the membrane testing assembly. Firstly, when material exiting the heating tube enters the buffer tank, any liquid material that hasn't formed vapor will remain there, while the liquid material that has formed vapor will exit from the buffer tank and enter the membrane testing assembly. This effectively prevents liquid material from entering the membrane testing unit and contaminating the membrane separation material, thus avoiding damage to the membrane structure. Secondly, the buffer tank provides pressure stabilization for the mixed pentane separation membrane performance testing system, ensuring stable pressure and vapor flow rate in the feeding unit, vaporization unit, membrane testing unit, and component detection unit. This prevents pressure instability from damaging the membrane structure and makes the test results more accurate and reliable. Furthermore, the inventors discovered that for the mixed pentane system, n-pentane has a boiling point of 36.1℃, isopentane has a boiling point of 27.8℃, and cyclopentane has a boiling point of 49.2℃. This mixed pentane system is significantly affected by ambient temperature and is prone to volatilization and liquefaction. The present invention incorporates a temperature-controlled feed tank in the feeding unit. Storing the mixed pentane in the temperature-controlled feed tank can prevent the components from being affected by the ambient temperature, thereby avoiding problems such as large errors in feed concentration and unstable pressure inside the feed tank. This can improve the accuracy and reliability of membrane performance test results.

[0009] In a preferred embodiment, the component detection unit further includes a vacuum pump, which is positioned in the communication channel between the permeate-side outlet of the gas chromatograph and the membrane testing assembly. The vacuum pump is used to allow the components on the permeate side of the membrane testing assembly to enter the gas chromatograph. The introduction of the vacuum pump provides the necessary power for the components on the permeate side of the membrane testing assembly to enter the gas chromatograph for content analysis without introducing any additional components, simplifying the experimental process and providing guidance for industrial applications and testing. Furthermore, since the resulting gas contains no additional components, this mixed pentane separation membrane performance testing system can be subsequently applied to mixed pentane membrane separation systems to separate the target product from mixed pentane.

[0010] In one optional embodiment, the feeding unit further includes a liquid pump, which is disposed in the communication channel between the outlet of the temperature-controlled liquid tank and the inlet of the heating tube. The liquid pump is used to allow the mixed pentane in the temperature-controlled liquid tank to enter the heating tube.

[0011] Furthermore, the feeding unit also includes an inert gas supply device, which is used to apply pressure to the temperature-controlled liquid tank so that the mixed pentane in the temperature-controlled liquid tank enters the liquid pump.

[0012] In a preferred embodiment, the mixed pentane separation membrane performance testing system further includes a permeate collection unit, which is connected to the permeate-side outlet of the membrane testing assembly. The permeate collection unit is used to collect the permeate-side feed liquid of the membrane testing assembly.

[0013] Furthermore, a reflux channel is provided between the leachate collection unit and the temperature-controlled feed tank. The reflux channel is used to return the leachate to the temperature-controlled feed tank for recycling and reuse.

[0014] Furthermore, the system also includes a temperature detector located at the inlet of the membrane testing assembly to monitor the feed temperature of the mixed pentane vapor, thereby further improving the accuracy of the temperature during the membrane feed-side testing process.

[0015] Furthermore, the system also includes a pressure detector installed at the feed inlet of the membrane testing assembly to obtain the material pressure on the feed side of the membrane testing assembly.

[0016] In some alternative implementations, the material pressure parameters on the permeate side of the membrane testing assembly can be obtained directly from the vacuum pump reading, or they can be obtained by setting a pressure detector at the permeate side outlet of the membrane testing assembly.

[0017] Furthermore, the system also includes a flow detector installed at the permeate-side outlet of the membrane testing assembly to obtain the material molar flow rate on the permeate side of the membrane testing assembly.

[0018] In some alternative implementations, a flow detector may also be installed at the inlet of the membrane testing assembly to monitor the feed flow rate of the mixed pentane vapor.

[0019] Furthermore, the first heating device and the second heating device mentioned above can be an oven.

[0020] This invention also provides a method for testing the performance of a mixed pentane separation membrane, wherein the mixed pentane is a mixture of n-pentane and isopentane, or a mixture of n-pentane and cyclopentane. The performance of the mixed pentane separation membrane is tested using the aforementioned mixed pentane separation membrane performance testing system. The method for testing the performance of the mixed pentane separation membrane includes:

[0021] The mixed pentane in the feed unit is fed into the vaporization unit for vaporization to obtain mixed pentane vapor;

[0022] Mixed pentane vapor is introduced into the membrane testing unit for membrane separation. After membrane separation, the permeate-side material of the membrane testing assembly is introduced into the component detection unit for detection to obtain the content of each component in the permeate-side material of the membrane testing assembly.

[0023] Let i be the fast-permeating component in the mixed pentane, j be the slow-permeating component, and P be the permeation flux of the membrane testing module for component i. i The unit is mol·m -2 ·s -1 ·Pa -1 P i The separation selectivity of the membrane test module for component i is calculated by equation (1); α is denoted as α and is calculated by equation (2).

[0024]

[0025]

[0026] Where, N i This represents the molar flow rate (mol·s) of component i on the permeate side of the membrane testing assembly. -1 );

[0027] ΔP i This represents the pressure difference between the feed side and the permeate side of component i in the membrane testing assembly;

[0028] A represents the effective permeation area of ​​the membrane testing module;

[0029] X i，perm This represents the mole fraction of component i on the permeate side of the membrane testing assembly;

[0030] X i，feed This represents the mole fraction of component i on the permeate side of the membrane testing assembly;

[0031] Xj，perm This represents the mole fraction of component j on the permeate side of the membrane testing assembly;

[0032] X j，feed This represents the mole fraction of component j on the feed side of the membrane testing assembly.

[0033] Furthermore, the vaporization treatment temperature is 45–110°C.

[0034] Furthermore, the absolute pressure on the feed side of the membrane testing assembly is 1.0–5.0 bar. Attached Figure Description

[0035] Figure 1 This is a schematic diagram of a mixed pentane separation membrane performance testing system according to one embodiment of the present invention.

[0036] Figure 2 This is a schematic diagram of a temperature-controlled liquid tank in one embodiment of the present invention.

[0037] Figure 3 This is a schematic diagram of a vaporization unit in one embodiment of the present invention.

[0038] Figure 4 This is a schematic diagram of a membrane testing unit in one embodiment of the present invention.

[0039] Figure 5 The graph shows the separation performance of the membrane obtained by the mixed pentane separation membrane performance testing method in Example 1 of this invention.

[0040] Figure 6 The graph shows the separation performance of the membrane obtained by the mixed pentane separation membrane performance testing method in Example 2 of this invention.

[0041] Figure 7 The graph shows the separation performance of the membrane obtained by the mixed pentane separation membrane performance testing method in Example 3 of this invention.

[0042] Figure 8 The graph shows the separation performance test results of the membrane obtained by the mixed pentane separation membrane test method in Comparative Example 1 of this invention.

[0043] The components are as follows: A. Feeding unit; B. Vaporization unit; C. Permeate collection unit; D. Membrane testing unit; E. Component detection unit; 1. Temperature-controlled feed tank; 2. Feed pump; 3. Three-way valve; 4. Heating tube; 5. Buffer tank; 6. Temperature detector; 7. Membrane testing assembly; 8. Flow detector; 9. Pressure detector; 10. Permeate storage tank; 11. Permeate condenser; 12. Vacuum pump; 13. Gas chromatograph; 14. Pressure gas pipeline valve; 15. First heating oven; 16. Second heating oven. Detailed Implementation

[0044] In order to provide a clearer understanding of the technical features, objectives and beneficial effects of the present invention, the technical solution of the present invention will now be described in detail below, but it should not be construed as limiting the scope of implementation of the present invention.

[0045] Example 1

[0046] This embodiment provides a mixed pentane separation membrane performance testing system, such as... Figure 1 As shown, the testing system includes a feeding unit A, a vaporization unit B, a membrane testing unit D, a component detection unit E, and a permeate collection unit C; wherein:

[0047] (a) Feeding unit A includes a temperature-controlled liquid tank 1, a liquid pump 2, a three-way valve 3 (with a feed inlet, a discharge outlet and an exhaust outlet), and a pressure gas pipeline valve 14;

[0048] Temperature-controlled liquid tank 1 is used to store mixed pentane; such as Figure 2 As shown, the temperature-controlled liquid tank 1 is connected to a nitrogen pipeline (i.e., an inert gas supply device) via a pipeline (on which a pressure gas pipeline valve 14 is installed), and to a liquid pump 2 via another pipeline; the liquid pump 2 is connected to the inlet of the three-way valve 3; the liquid pump 2 is used to allow the mixed pentane in the temperature-controlled liquid tank 1 to enter the vaporization unit B.

[0049] (ii) The vaporization unit B includes a first heating oven 15, a heating tube 4, and a buffer tank 5;

[0050] like Figure 3 As shown, the heating tube 4 and the buffer tank 5 are placed in the inner cavity of the first heating oven 15; the inlet of the heating tube 4 is connected to the outlet of the three-way valve 3; the outlet of the heating tube 4 is connected to the inlet of the buffer tank 5.

[0051] (III) The membrane testing unit D includes a second heating oven 16, a membrane testing assembly 7, a pressure detector 9, and a temperature detector 6;

[0052] like Figure 4 As shown, the membrane testing assembly 7 is placed in the inner cavity of the second heating oven 16; the inlet of the membrane testing assembly 7 is connected to the outlet of the buffer tank 5; the temperature detector 6 is set at the inlet of the membrane testing assembly; and the pressure detector 9 is set at the inlet of the membrane testing assembly.

[0053] (iv) The component detection unit E includes a vacuum pump 12, a gas chromatograph 13, and a flow detector 8;

[0054] The inlet of the gas chromatograph 13 is connected to the permeate-side outlet of the membrane testing assembly 7 to obtain the content of each component on the permeate side of the membrane testing assembly 7; the flow detector 8 is set at the permeate-side outlet of the membrane testing assembly; the vacuum pump 12 is set on the connecting channel between the gas chromatograph 13 and the permeate-side outlet of the membrane testing assembly 7 to allow each component on the permeate side of the membrane testing assembly 7 to enter the gas chromatograph 13.

[0055] (v) The leachate collection unit C includes a leachate storage tank 10 and a leachate condenser 11;

[0056] The inlet of the residual liquid storage tank 10 is connected to the outlet of the residual side of the membrane testing assembly 7 to collect the liquid from the residual side of the membrane testing assembly 7; the residual liquid condenser 11 is arranged around the outer wall of the residual liquid storage tank 10 to cool the residual liquid and prevent the residual liquid from entering the atmosphere in a gaseous form and polluting the environment; a reflux channel is provided between the residual liquid storage tank 10 and the temperature-controlled liquid tank 1 to allow the residual liquid from the membrane testing assembly 7 to flow back to the temperature-controlled liquid tank 1.

[0057] This embodiment provides a method for testing the performance of a mixed pentane separation membrane, using the above-mentioned... Figure 1 The performance testing system for the mixed pentane separation membrane shown was tested, and the following steps were included:

[0058] Prepare a mixed pentane solution (molar ratio of n-pentane to cyclopentane = 1:1) and store it in a temperature-controlled liquid tank 1, which is kept at a constant temperature of 20°C.

[0059] Turn on all devices in vaporization unit B, membrane testing unit D, and component detection unit E to a stable state. Specifically, maintain the first heating oven 15 at 70°C, maintain the second heating oven 16 at 70°C, maintain the absolute pressure on the feed side of membrane testing assembly 7 at 2.0 bar, and maintain the absolute pressure of vacuum pump 12 close to 0.0 bar. Extract gas from the system pipeline and stabilize the reading of flow detector 8.

[0060] The mixed pentane liquid in the temperature-controlled feed tank 1 is pressurized by inert gas supplied from the inert gas supply equipment, so that the mixed pentane in the temperature-controlled feed tank 1 enters the feed pump 2. After all the mixed liquid is pumped into the feed pump 2 under the power of nitrogen pressure, the nitrogen power gas is removed.

[0061] The mixed liquid enters the heating tube 4 through the liquid pump 2 for vaporization, volatilizing into n-pentane and isopentane vapor materials. The n-pentane and isopentane vapor materials are further removed by the buffer tank 5 to remove unevaporated and unvaporized liquid phase materials, and then enter the membrane testing module 7 for membrane separation.

[0062] After membrane separation, the molar flow rate N of component i on the permeate side of membrane test module 7 is obtained by flow detector 8. i(mol·s -1 The total vapor pressure on the feed side of membrane testing module 7 is obtained through pressure detector 9, and the total vapor pressure on the permeate side of membrane testing module 7 is obtained through vacuum pump 12 reading. The partial pressures of component i on the feed side and permeate side are obtained according to Dalton's law of partial pressures, and thus the pressure difference ΔP between component i on the feed and permeate sides is obtained. i The permeation flux value was determined. The molar fractions of component i (n-pentane) and component j (cyclopentane) on the permeate side of membrane testing module 7 were obtained by gas chromatography (GC) to obtain X. i，pem / X i，feed and X j，pem / X j，feed Calculate the value of the separation factor.

[0063] Let P be the permeation flux of membrane testing module 7 for component i. i The unit is mol·m -2 ·s -1 ·Pa -1 P is calculated using equation (1) i Let α be the separation selectivity of membrane testing component 7 for component i. α is calculated using equation (2), and the result is as follows: Figure 5 As shown.

[0064]

[0065] Example 2

[0066] This embodiment provides a mixed pentane separation membrane performance testing system, such as... Figure 1 As shown, the testing system includes a feeding unit A, a vaporization unit B, a membrane testing unit D, a component detection unit E, and a permeate collection unit C; wherein:

[0067] (a) Feeding unit A includes a temperature-controlled liquid tank 1, a liquid pump 2, a three-way valve 3 (with a feed inlet, a discharge outlet and an exhaust outlet), and a pressure gas pipeline valve 14;

[0068] Temperature-controlled liquid tank 1 is used to store mixed pentane; such as Figure 2 As shown, the temperature-controlled liquid tank 1 is connected to the nitrogen pipeline through a pipeline (which is equipped with a pressure gas pipeline valve 14), and to the liquid pump 2 through another pipeline; the liquid pump 2 is connected to the feed port of the three-way valve 3; the liquid pump 2 is used to allow the mixed pentane in the temperature-controlled liquid tank 1 to enter the vaporization unit B.

[0069] (ii) The vaporization unit B includes a first heating oven 15, a heating tube 4, and a buffer tank 5;

[0070] like Figure 3As shown, the heating tube 4 and the buffer tank 5 are placed in the inner cavity of the first heating oven 15; the inlet of the heating tube 4 is connected to the outlet of the three-way valve 3; the outlet of the heating tube 4 is connected to the inlet of the buffer tank 5.

[0071] (III) The membrane testing unit D includes a second heating oven 16, a membrane testing assembly 7, a pressure detector 9, and a temperature detector 6;

[0072] like Figure 4 As shown, the membrane testing assembly 7 is placed in the inner cavity of the second heating oven 16; the inlet of the membrane testing assembly 7 is connected to the outlet of the buffer tank 5; the temperature detector 6 is set at the inlet of the membrane testing assembly; and the pressure detector 9 is set at the inlet of the membrane testing assembly.

[0073] (iv) The component detection unit E includes a vacuum pump 12, a gas chromatograph 13, and a flow detector 8;

[0074] The inlet of the gas chromatograph 13 is connected to the permeate-side outlet of the membrane testing assembly 7 to obtain the content of each component on the permeate side of the membrane testing assembly 7; the flow detector 8 is set at the permeate-side outlet of the membrane testing assembly; the vacuum pump 12 is set on the connecting channel between the gas chromatograph 13 and the permeate-side outlet of the membrane testing assembly 7 to allow each component on the permeate side of the membrane testing assembly 7 to enter the gas chromatograph 13.

[0075] (v) The leachate collection unit C includes a leachate storage tank 10 and a leachate condenser 11;

[0076] The inlet of the residual liquid storage tank 10 is connected to the outlet of the residual side of the membrane testing assembly 7 to collect the liquid from the residual side of the membrane testing assembly 7; the residual liquid condenser 11 is arranged around the outer wall of the residual liquid storage tank 10 to cool the residual liquid and prevent the residual liquid from entering the atmosphere in a gaseous form and polluting the environment; a reflux channel is provided between the residual liquid storage tank 10 and the temperature-controlled liquid tank 1 to allow the residual liquid from the membrane testing assembly 7 to flow back to the temperature-controlled liquid tank 1.

[0077] This embodiment provides a method for testing the performance of a mixed pentane separation membrane, using the above-mentioned... Figure 1 The performance testing system for the mixed pentane separation membrane shown was tested, and the following steps were included:

[0078] Prepare a mixed pentane solution (molar ratio of n-pentane to cyclopentane = 1:1) and store it in a temperature-controlled liquid tank 1, which is kept at a constant temperature of 20°C.

[0079] Turn on all devices in vaporization unit B, membrane testing unit D, and component detection unit E to a stable state. Specifically, maintain the first heating oven 15 at 45°C, maintain the second heating oven 16 at 45°C, maintain the absolute pressure on the feed side of membrane testing assembly 7 at 1.0 bar, and maintain the absolute pressure of vacuum pump 12 close to 0.0 bar. Extract gas from the system pipeline and stabilize the reading of flow detector 8.

[0080] The inert gas in the inert gas supply device applies a certain pressure to the mixed pentane liquid in the temperature-controlled liquid tank 1, causing the mixed pentane in the temperature-controlled liquid tank 1 to enter the liquid pump 2. Under the power of nitrogen pressure, the mixed liquid is pumped into the liquid pump 2 and then the nitrogen power gas is removed.

[0081] The mixed liquid enters the heating tube 4 through the liquid pump 2 for vaporization treatment, and evaporates into n-pentane / isopentane vapor material. The n- / isopentane vapor material passes through the buffer tank 5 in the channel leading to the vaporization unit B to further remove liquid phase material, and then enters the membrane test module 7 for membrane separation treatment.

[0082] After membrane separation, the molar flow rate N of component i on the permeate side of membrane test module 7 is obtained by flow detector 8. i (mol·s -1 The total vapor pressure on the feed side of membrane testing module 7 is obtained through pressure detector 9, and the total vapor pressure on the permeate side of membrane testing module 7 is obtained through vacuum pump 12 reading. The partial pressures of component i on the feed side and permeate side are obtained according to Dalton's law of partial pressures, and thus the pressure difference ΔP between component i on the feed and permeate sides is obtained. i The permeation flux value was determined. The molar fractions of component i (n-pentane) and component j (cyclopentane) on the permeate side of membrane testing module 7 were obtained by gas chromatography (GC) to obtain X. i，pem / X i，feed and X j，pem / X j，feed Calculate the value of the separation factor.

[0083] Let P be the permeation flux of membrane testing module 7 for component i. i The unit is mol·m -2 ·s -1 ·Pa -1 P is calculated using equation (1) i Let α be the separation selectivity of membrane testing component 7 for component i. α is calculated using equation (2), and the result is as follows: Figure 6 As shown.

[0084]

[0085]

[0086] Example 3

[0087] This embodiment provides a mixed pentane separation membrane performance testing system, such as... Figure 1 As shown, the testing system includes a feeding unit A, a vaporization unit B, a membrane testing unit D, a component detection unit E, and a permeate collection unit C; wherein:

[0088] (a) Feeding unit A includes a temperature-controlled liquid tank 1, a liquid pump 2, a three-way valve 3 (with a feed inlet, a discharge outlet and an exhaust outlet), and a pressure gas pipeline valve 14;

[0089] Temperature-controlled liquid tank 1 is used to store mixed pentane; such as Figure 2 As shown, the temperature-controlled liquid tank 1 is connected to the nitrogen pipeline through a pipeline (which is equipped with a pressure gas pipeline valve 14), and to the liquid pump 2 through another pipeline; the liquid pump 2 is connected to the feed port of the three-way valve 3; the liquid pump 2 is used to allow the mixed pentane in the temperature-controlled liquid tank 1 to enter the vaporization unit B.

[0090] (ii) The vaporization unit B includes a first heating oven 15, a heating tube 4, and a buffer tank 5;

[0091] like Figure 3 As shown, the heating tube 4 and the buffer tank 5 are placed in the inner cavity of the first heating oven 15; the inlet of the heating tube 4 is connected to the outlet of the three-way valve 3; the outlet of the heating tube 4 is connected to the inlet of the buffer tank 5.

[0092] (III) The membrane testing unit D includes a second heating oven 16, a membrane testing assembly 7, a pressure detector 9, and a temperature detector 6;

[0093] like Figure 4 As shown, the membrane testing assembly 7 is placed in the inner cavity of the second heating oven 16; the inlet of the membrane testing assembly 7 is connected to the outlet of the buffer tank 5; the temperature detector 6 is set at the inlet of the membrane testing assembly; and the pressure detector 9 is set at the inlet of the membrane testing assembly.

[0094] (iv) The component detection unit E includes a vacuum pump 12, a gas chromatograph 13, and a flow detector 8;

[0095] The inlet of the gas chromatograph 13 is connected to the permeate-side outlet of the membrane testing assembly 7 to obtain the content of each component on the permeate side of the membrane testing assembly 7; the flow detector 8 is set at the permeate-side outlet of the membrane testing assembly; the vacuum pump 12 is set on the connecting channel between the gas chromatograph 13 and the permeate-side outlet of the membrane testing assembly 7 to allow each component on the permeate side of the membrane testing assembly 7 to enter the gas chromatograph 13.

[0096] (v) The leachate collection unit C includes a leachate storage tank 10 and a leachate condenser 11;

[0097] The inlet of the residual liquid storage tank 10 is connected to the outlet of the residual side of the membrane testing assembly 7 to collect the liquid from the residual side of the membrane testing assembly 7; the residual liquid condenser 11 is arranged around the outer wall of the residual liquid storage tank 10 to cool the residual liquid and prevent the residual liquid from entering the atmosphere in a gaseous form and polluting the environment; a reflux channel is provided between the residual liquid storage tank 10 and the temperature-controlled liquid tank 1 to allow the residual liquid from the membrane testing assembly 7 to flow back to the temperature-controlled liquid tank 1.

[0098] This embodiment provides a method for testing the performance of a mixed pentane separation membrane, using the above-mentioned... Figure 1 The performance testing system for the mixed pentane separation membrane shown was tested, and the following steps were included:

[0099] Prepare a mixed pentane solution (molar ratio of n-pentane to cyclopentane = 1:1) and store it in a temperature-controlled liquid tank 1, which is kept at a constant temperature of 20°C.

[0100] Turn on all devices in vaporization unit B, membrane testing unit D, and component detection unit E to a stable state. Specifically, maintain the first heating oven 15 at 120°C, maintain the second heating oven 16 at 120°C, maintain the absolute pressure on the feed side of membrane testing assembly 7 at 5.0 bar, and maintain the absolute pressure of vacuum pump 12 close to 0.0 bar. Extract gas from the system pipeline and stabilize the reading of flow detector 8.

[0101] The inert gas in the inert gas supply device applies a certain pressure to the mixed pentane liquid in the temperature-controlled liquid tank 1, causing the mixed pentane in the temperature-controlled liquid tank 1 to enter the liquid pump 2. Under the power of nitrogen pressure, the mixed liquid is pumped into the liquid pump 2 and then the nitrogen power gas is removed.

[0102] The mixed liquid enters the heating tube 4 through the liquid pump 2 for vaporization treatment, and evaporates into n-pentane / isopentane vapor material. The n- / isopentane vapor material passes through the buffer tank 5 in the channel leading to the vaporization unit B to further remove liquid phase material, and then enters the membrane test module 7 for membrane separation treatment.

[0103] After membrane separation, the molar flow rate N of component i on the permeate side of membrane test module 7 is obtained by flow detector 8. i (mol·s -1 The total vapor pressure on the feed side of membrane testing module 7 is obtained through pressure detector 9, and the total vapor pressure on the permeate side of membrane testing module 7 is obtained through vacuum pump 12 reading. The partial pressures of component i on the feed side and permeate side are obtained according to Dalton's law of partial pressures, and thus the pressure difference ΔP between component i on the feed and permeate sides is obtained. i The permeation flux value was determined. The molar fractions of component i (n-pentane) and component j (cyclopentane) on the permeate side of membrane testing module 7 were obtained by gas chromatography (GC) to obtain X. i，pem / Xi，feed and X j，pem / X j，feed Calculate the value of the separation factor.

[0104] Let P be the permeation flux of membrane testing module 7 for component i. i The unit is mol·m -2 ·s -1 ·Pa -1 P is calculated using equation (1) i Let α be the separation selectivity of membrane testing component 7 for component i. α is calculated using equation (2), and the result is as follows: Figure 7 As shown.

[0105]

[0106]

[0107] Comparative Example 1

[0108] This comparative example provides a mixed pentane separation membrane performance testing system, which differs from Example 1 only in that it does not include vaporization unit B. This comparative example uses a liquid feed method to determine the performance of the separation membrane module.

[0109] Taking the separation of mixed pentane components of n-pentane and cyclopentane as an example: prepare a mixed pentane solution (molar ratio of n-pentane and cyclopentane = 1:1), load it into the feed tank, and ensure a constant temperature of 20℃.

[0110] (2) Turn on the vacuum pump and other devices to a stable state. The absolute pressure of the vacuum pump approaches 0.0 bar, extract the gas in the pipeline, and keep the flow meter reading stable (without a preheating module, the feed solution is in liquid phase).

[0111] (3) Connect nitrogen gas. Under the pressure of nitrogen gas, the mixed liquid is driven into the feed pump and enters the membrane test module in liquid form for the separation of mixed pentane components in the liquid feed process.

[0112] After membrane separation, the molar flow rate N of component i on the permeate side of membrane test module 7 is obtained by flow detector 8. i (mol·s -1 The total pressure of the feed liquid in membrane testing module 7 is obtained through pressure detector 9, and the partial pressure of component i is calculated according to Raoult's law. The total pressure on the permeate side of membrane testing module 7 is obtained through reading the vacuum pump 12, and the partial pressure of component i on the permeate side is obtained according to Dalton's law of partial pressures. The pressure difference ΔP between component i on the feed side and the permeate side is then obtained. i The permeation flux value was determined. The molar fractions of component i (n-pentane) and component j (cyclopentane) on the permeate side of membrane testing module 7 were obtained by gas chromatography (GC) to obtain X. i，perm / Xi，feed and X j，perm / X j，feed Calculate the value of the separation factor.

[0113] Let P be the permeation flux of the membrane testing module for component i. i The unit is mol·m -2 ·s -1 ·Pa -1 P is calculated using equation (1) i Let α be the separation selectivity of the membrane testing module for component i. α is calculated using equation (2), and the result is as follows: Figure 8 As shown.

[0114]

[0115]

[0116] In Comparative Example 1, the membrane structure was damaged. Figure 8 The selectivity of the membrane separation and the permeation flux of component i were significantly reduced.

[0117] By comparison Figures 5-8 It can be observed that the permeability and selectivity of the membranes in Examples 1-3 are better than those in Comparative Example 1. The above-mentioned technical solutions of the present invention can effectively avoid damage to the membrane structure, thereby obtaining membrane performance data more accurately.

Claims

1. A performance testing system for a mixed pentane separation membrane, characterized in that, It includes a feed unit, a vaporization unit, a membrane testing unit, and a component detection unit that are connected in sequence; The feeding unit includes a temperature-controlled liquid tank, which is used to store mixed pentane; The vaporization unit includes a first heating device and a heating pipe and a buffer tank that are sequentially connected and placed inside the cavity of the first heating device. The inlet of the heating pipe is connected to the outlet of the temperature-controlled liquid tank. The membrane testing unit includes a second heating device and a membrane testing assembly placed inside the cavity of the second heating device. The inlet of the membrane testing assembly is connected to the outlet of the buffer tank. The component detection unit includes a gas chromatograph, which is connected to the permeate-side outlet of the membrane testing assembly.

2. The mixed pentane separation membrane performance testing system according to claim 1, characterized in that, The component detection unit also includes a vacuum pump, which is disposed on the communication channel between the permeate side outlet of the gas chromatograph and the membrane testing assembly.

3. The mixed pentane separation membrane performance testing system according to claim 1, characterized in that, The feeding unit also includes a liquid pump, which is located on the connecting channel between the outlet of the temperature-controlled liquid tank and the inlet of the heating tube.

4. The mixed pentane separation membrane performance testing system according to claim 3, characterized in that, The feeding unit also includes an inert gas supply device, which is used to apply pressure to the temperature-controlled liquid tank so that the mixed pentane in the temperature-controlled liquid tank enters the liquid pump.

5. The mixed pentane separation membrane performance testing system according to claim 1, characterized in that, It also includes a permeate collection unit, which is connected to the permeate side outlet of the membrane testing assembly.

6. The mixed pentane separation membrane performance testing system according to claim 5, characterized in that, A reflux channel is provided between the residual liquid collection unit and the temperature-controlled liquid tank.

7. The mixed pentane separation membrane performance testing system according to claim 1, characterized in that, Also includes: A temperature detector is installed at the inlet of the membrane testing assembly to monitor the feed temperature of the mixed pentane vapor; A pressure detector is installed at the feed inlet of the membrane testing assembly, the pressure detector being used to acquire the material pressure on the feed side of the membrane testing assembly; A flow detector is installed at the permeate-side outlet of the membrane testing assembly, the flow detector being used to acquire the material molar flow rate on the permeate side of the membrane testing assembly.

8. A method for testing the performance of a mixed pentane separation membrane, wherein the mixed pentane is a mixture of n-pentane and isopentane, or a mixture of n-pentane and cyclopentane, characterized in that, The mixed pentane separation membrane performance testing system according to any one of claims 1 to 7 is used for testing, and the testing method includes: The mixed pentane in the feed unit is fed into the vaporization unit for vaporization to obtain mixed pentane vapor; The mixed pentane vapor is introduced into the membrane testing unit for membrane separation treatment. After the membrane separation treatment, the permeate-side material of the membrane testing assembly is introduced into the component detection unit for detection to obtain the content of each component in the permeate-side material of the membrane testing assembly. Let i be the fast-permeating component in the mixed pentane, j be the slow-permeating component, and P be the permeation flux of the membrane testing assembly for component i. i The unit is mol·m -2 ·s -1 ·Pa -1 The P i The separation selectivity of the membrane testing assembly for component i is denoted as α, which is calculated using equation (2). Where, N i This represents the molar flow rate of component i on the permeate side of the membrane test assembly; ΔP i This represents the pressure difference between the feed side and the permeate side of component i in the membrane testing assembly; A represents the effective permeation area of ​​the membrane testing assembly; X i,perm This represents the mole fraction of component i on the permeate side of the membrane test assembly; X i,feed This represents the mole fraction of component i in the mixed pentane; X j,perm This indicates the mole fraction of component j on the permeate side of the membrane testing assembly; X j,feed This indicates the mole fraction of component j in the mixed pentane.

9. The method for testing the performance of a mixed pentane separation membrane according to claim 8, characterized in that, The vaporization treatment temperature is 45–110°C.

10. The method for testing the performance of a mixed pentane separation membrane according to claim 8, characterized in that, The absolute pressure on the feed side of the membrane testing assembly is 1.0 to 5.0 bar.

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