Preparation device and method for continuously preparing PDMS hollow fiber composite membrane

Abstract

The invention discloses a preparation device and method for continuously preparing a PDMS hollow fiber composite membrane. The device comprises a material supply unit, a wetting agent extraction unit, a membrane coating unit, a curing unit and a material receiving unit, the feeding unit comprises a feeding box, a first rotating cylinder is arranged in the feeding box, and the wetting agent extraction unit comprises an extraction tank and a drying tunnel which are sequentially arranged in the base membrane conveying direction; the film coating unit comprises a feed liquid tank, a coating head and a low-temperature circulating system; the curing unit comprises a curing tunnel furnace and a second curing tunnel furnace which are arranged up and down at an interval; the material collecting unit comprises a wire collecting box, and a second rotating cylinder is arranged in the wire collecting box; according to the continuous preparation method, the hollow fiber membrane is continuously and sequentially wetted, dried, coated with the coating liquid and cured, so that continuous preparation is realized; according to the preparation device and method, the functional layer is compounded on the surface of the base membrane, the strength of the hollow fiber composite membrane is ensured, the thickness of the functional layer is reduced, and the hollow fiber composite membrane has a functional separation characteristic and relatively high flux.

Description

Technical Field

[0001] The invention relates to the technical field of membrane manufacturing, and in particular to a preparation device and method for continuously preparing a PDMS hollow fiber composite membrane. Background Art

[0002] Hollow fiber composite membranes are widely used in various separation fields such as industrial and municipal sewage treatment, landscape river water treatment, micro-polluted water purification, drinking water purification, water degassing, water gas supply, water reuse, gas separation, solvent-resistant nanofiltration, membrane extraction, pervaporation, etc. Hollow fiber membranes have high packing density, large effective membrane area, high separation efficiency, and simple structure, and thus have become an important development direction in the field of membrane preparation.

[0003] Polydimethylsiloxane (PDMS) is a highly permeable material. Composite membranes with PDMS as the separation layer are widely used in pervaporation, solvent recovery, gas separation and other fields. However, the continuous preparation of defect-free PDMS composite membranes remains a challenge. To this end, the following problems must be solved: (1) After the PDMS prepolymer is treated with a crosslinker and a catalyst, it will inevitably undergo a continuous change from a linear PDMS prepolymer to a three-dimensional network in the solution tank, resulting in differences in the performance of the coating at different time points. In addition, as the viscosity of PDMS increases, it easily forms a gel in the solution tank, which significantly affects the coatability of the PDMS coating solution; (2) Before winding onto a roll, the PDMS layer must be cured to prevent adhesion of adjacent membranes after winding. However, the entire curing process reported in the literature usually lasts for several hours or even days of thermal curing. This is incompatible with the requirement of controlling the PDMS crosslinking reaction in the solution tank; (3) After coating, the separation layer will invade the pores of the porous support layer to form pinholes or defects, resulting in poor separation performance or low permeation flux. Generally speaking, filling the pores with a pre-wetting agent before coating is an effective way to prevent the coating solution from invading the pores and entering the support layer. Therefore, the production process of PDMS composite membranes is cumbersome, inefficient, and prone to defects or pore permeation, and cannot be produced in a continuous manner.

[0004] The published patent CN109603569A proposes a membrane-making device and method for continuously preparing a composite membrane with a separation layer of PDMS, and the published patent CN112403839A discloses a large-scale preparation method and device for a multi-layer composite membrane for carbon dioxide separation. However, the above patents disclose membrane-making devices for flat composite membranes and corresponding membrane production methods, and there are few reports on the method and device for continuously preparing PDMS hollow fiber composite membranes. At present, the method for preparing PDMS hollow fiber composite membranes is generally achieved by dipping and pulling, but this method cannot achieve the continuous preparation of PDMS hollow fiber composite membranes.

[0005] Therefore, the continuous preparation of hollow fiber composite membranes with PDMS as the separation layer has become a difficult technical problem to overcome in this field. At present, it is urgent to develop a preparation device and method for continuously preparing defect-free PDMS hollow fiber composite membranes to meet the growing market demand. Summary of the invention

[0006] The purpose of the present invention is to provide a device for continuously preparing a PDMS hollow fiber composite membrane which solves the problems of the prior art.

[0007] Another object of the present invention is to provide a method for continuously preparing a PDMS hollow fiber composite membrane using the above-mentioned continuous preparation device for the PDMS hollow fiber composite membrane.

[0008] To this end, the technical solution of the present invention is as follows:

[0009] A preparation device for continuously preparing a PDMS hollow fiber composite membrane comprises a feeding unit, a wetting agent extraction unit, a film coating unit, a curing unit and a material receiving unit; wherein:

[0010] The feeding unit comprises a feeding box, in which a first rotating cylinder controlled by a feeding motor is arranged, and a discharge port is opened on a wall surface of the box body parallel to the axis of the first rotating cylinder;

[0011] The wetting agent extraction unit comprises an extraction tank and a drying tunnel which are sequentially arranged along the conveying direction of the base film; the extraction tank is an open strip tank, and a feed roller is respectively arranged at the slot opening and the slot bottom position close to the feed box, and a discharge roller is respectively arranged at the slot opening and the slot bottom position away from the feed box; the drying tunnel is arranged above the discharge roller, and comprises a drying cylinder with a vertical channel, and a first feed roller is arranged above the drying cylinder;

[0012] The coating unit includes a liquid tank, a coating head and a low-temperature circulation system; the liquid tank is an open tank body with a condenser spirally arranged on the wall, and its bottom end is a conical opening end; the coating head is a tank body with a condenser spirally arranged on the wall, and the inner diameter is adapted to the outer diameter of the film to be coated; the coating head is connected to the bottom end of the liquid tank, and the inner cavities of the two are connected; the low-temperature circulation system is connected to the condenser of the liquid tank and the coating head through pipelines to circulate the low-temperature cooling liquid; a second feeding roller is arranged side by side with the first feeding roller above the liquid tank;

[0013] The curing unit includes a first curing tunnel furnace and a second curing tunnel furnace, both of which include a drying drum with a vertical channel and are arranged at an upper and lower interval below the coating head; a third feeding roller is provided below the second curing tunnel furnace;

[0014] The receiving unit comprises a wire receiving box, in which a second rotating drum controlled by a feeding motor is arranged, a receiving opening is arranged on the box wall parallel to the axis of the second rotating drum and facing the curing unit, and a receiving roller is arranged adjacent to the receiving opening.

[0015] Furthermore, a tension regulator is provided at the discharge port of the feed box, which is composed of a tension testing device and a tension control device; the detection end of the tension testing device of the tension regulator contacts the base film extending from the discharge port to monitor the tension of the membrane filament passing through its detection end; the tension control device is respectively connected to the tension testing device and the feed motor, so that the tension control device adjusts the rotation speed of the feed motor based on the real-time tension test value.

[0016] Furthermore, in the feeding unit, the conveying speed of the first rotating drum is adjustable between 0.5m / min and 5m / s; in the wetting agent extraction unit, the length of the extraction tank in the base membrane conveying direction is adapted to the theoretical extraction time of the base membrane and the feeding speed of the feeding unit; in the coating unit, the central aperture of the coating head is 1.01 to 1.5 times the diameter of the hollow fiber base membrane; in the curing unit, the length of the first curing tunnel furnace is 0.5m to 2m, and its internal temperature is adjustable between 25°C and 80°C; the length of the second curing tunnel furnace is 1m to 5m, and its internal temperature is adjustable between 25°C and 200°C; in the receiving unit, the conveying speed of the second rotating drum is adjustable between 0.5m / min and 5m / min.

[0017] Furthermore, the outer walls of the liquid tank and the coating head are both coated with a heat-insulating layer.

[0018] A method for continuously preparing a PDMS hollow fiber composite membrane using the above-mentioned device for continuously preparing a PDMS hollow fiber composite membrane comprises the following steps:

[0019] S1, soaking the hollow fiber base membrane in a wetting agent for pretreatment, and then winding it on a reel after drying and dehydration; the reel is installed on a first rotating drum, and the base membrane end thereon is sequentially passed through and wound on the rollers of each unit, and finally wound and fixed on a receiving drum;

[0020] S2, filling the extraction tank with extraction liquid, and adjusting the feeding speed of the feeding unit so that the time for the base film to pass through the membrane fiber path in the extraction tank meets the extraction time; setting the drying temperature of the drying tunnel;

[0021] S3. Prepare coating liquid: after polydimethylsiloxane, catalyst, inhibitor and solvent are evenly mixed, then add cross-linking agent and mix well and degas; pour the prepared coating liquid into the liquid tank, and start the low-temperature cooling liquid circulation system to keep the coating liquid in the liquid tank at a low temperature;

[0022] S4, respectively setting the drying temperature of the first curing reaction tunnel furnace and the curing temperature of the second curing reaction tunnel furnace;

[0023] S5. Start the feeding motor and the receiving motor in sequence to realize the continuous preparation of the PDMS hollow fiber composite membrane.

[0024] Further, in step S1, the hollow fiber-based membrane is selected from any one of polyvinylidene fluoride membrane (PVDF), polysulfone membrane (PSF), polyacrylonitrile membrane (PAN), polypropylene membrane (PP), polyethylene membrane (PE), polytetrafluoroethylene membrane (PTFE), polyethersulfone membrane (PES), sulfonated polyethersulfone membrane (SPES), polyimide membrane (PI), polyetherimide membrane (PEI), and polyetheretherketone membrane (PEEK).

[0025] Furthermore, in step S1, the base film is pre-soaked in a wetting agent for 5 minutes to 24 hours; the wetting agent is glycerol or paraffin oil.

[0026] Furthermore, in step S2, the extraction liquid is water, ethanol, methanol, isopropanol, petroleum ether or n-hexane, and the extraction time is 1s to 30s; the drying temperature of the drying tunnel is set to 25°C to 80°C.

[0027] Furthermore, in step S3, the mass ratio of polydimethylsiloxane, crosslinking agent, catalyst and inhibitor is (1-20):1:(0.01-0.5):(0.002-0.5); polydimethylsiloxane adopts polydimethylsiloxane with end-capping vinyl group or polydimethylsiloxane with side group being vinyl group, and its molecular weight is 200g / mol-100000g / mol; the crosslinking agent is hydrogenated silicone oil, the catalyst is platinum catalyst, the inhibitor is acetylenic alcohol substance, and the solvent is n-hexane, n-heptane, chloroform, dichloromethane or toluene; the amount of solvent added satisfies: the mass fraction of polydimethylsiloxane, crosslinking agent, catalyst and inhibitor in the coating liquid is 1wt.%-100wt.%.

[0028] Furthermore, in step S3, the degassing condition is to stand and degas at -30 to 5°C for 30 minutes to 12 hours.

[0029] Furthermore, in step S4, the drying temperature of the first curing reaction tunnel furnace (8) is set to 25°C to 80°C; and the curing temperature of the second curing reaction tunnel furnace is set to 25°C to 200°C.

[0030] Further, in step S5, the feeding motor supplies the base film at a feeding speed of 0.5 m / min to 5 m / min, and the winding motor drives the winding drum to wind the composite film wire at a winding speed of 0.5 m / min to 5 m / min.

[0031] Compared with the prior art, the preparation device for continuously preparing PDMS hollow fiber composite membranes includes a feeding unit, a wetting agent extraction unit, a coating unit, a curing unit and a collecting unit, which realizes the continuous preparation of hollow fiber composite membranes and ensures that the coating liquid is evenly coated on the surface of the hollow fiber support layer membrane to form a functional layer; at the same time, the device cooperates with the corresponding preparation method to ensure the strength of the hollow fiber composite membrane and effectively control the permeation thickness of the functional layer, so that the prepared PDMS hollow fiber composite membrane has functional separation characteristics and a higher flux. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 It is a structural schematic diagram of the device for continuously preparing PDMS hollow fiber composite membrane of the present invention;

[0033] Figure 2 It is a structural schematic diagram of a tension regulator of the device for continuously preparing PDMS hollow fiber composite membranes of the present invention;

[0034] Figure 3 It is a schematic structural diagram of a feed liquid tank and a coating head of the device for continuously preparing a PDMS hollow fiber composite membrane of the present invention. DETAILED DESCRIPTION

[0035] The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments, but the following embodiments are by no means intended to limit the present invention in any way.

[0036] Example 1

[0037] See also Figure 1 The continuous preparation device for PDMS hollow fiber composite membrane comprises a feeding unit, a wetting agent extraction unit, a coating unit, a curing unit and a collecting unit.

[0038] The feeding unit includes a feeding box 1, in which a first rotating drum 101 controlled by a feeding motor is provided, and a discharge port is opened on the wall of the box body parallel to the axis of the first rotating drum 101, and the discharge port is preferably arranged on the upper side of the feeding box 1; when in use, the hollow fiber base membrane wound on the reel is passed through the reel and fixed on the first rotating drum 101, and the membrane wire end of the hollow fiber base membrane is stretched in the horizontal direction and extends from the discharge port; the feeding motor drives the first rotating drum 101 to rotate, and the first rotating drum 101 drives the reel wound with the hollow fiber base membrane to rotate synchronously, so as to continuously supply the base membrane to the next unit, namely the wetting agent extraction unit.

[0039] In order to ensure that the base film does not bend due to too fast feeding speed or break due to excessive tension during feeding, please refer to Figure 2A tension regulator 2 is also provided at the outlet of the feed box 1, which is composed of a tension test device and a tension control device; the base film extending from the outlet passes through the detection end of the tension test device of the tension regulator 2, so that the tension of the film passing through the detection end is monitored in real time by the tension test device; the tension control device is connected to the tension test device and the feed motor respectively, so that the tension control device adjusts the rotation speed of the feed motor to speed up or slow down based on the real-time tension test value, so that the base film is fed within the set tension value range. Preferably, the conveying speed of the base film is preferably 1m / min±0.01m / min.

[0040] The wetting agent extraction unit is arranged adjacent to the feed box 1 and at a position opposite to the discharge port on the feed box 1, so that the hollow fiber base membrane first enters the wetting agent extraction unit for extraction treatment; specifically, the wetting agent extraction unit includes an extraction tank 3 and a drying tunnel 4 arranged in sequence along the base membrane conveying direction.

[0041] The extraction tank 3 is an open strip tank, the end of which is close to the feeding box 1 as the feeding end, and the end of which is far from the feeding box 1 as the discharging end; a feeding roller 301 is provided at the slot opening and the bottom of the slot at the feeding end of the extraction tank 3 by means of a roller frame for rolling, and a discharging roller 302 is provided at the slot opening and the bottom of the slot at the discharging end of the extraction tank 3 by means of a roller frame for rolling, and the two feeding rollers 301 and the two discharging rollers 302 are both provided with their axes parallel to the direction of the axis of the first rotating cylinder 101 The base membrane end extending from the feeding unit is arranged so that it first passes through the two feeding rollers 301 counterclockwise from top to bottom, so that the base membrane gradually sinks to the bottom of the extraction tank 3, and then passes through the two discharging rollers 302 counterclockwise from bottom to top, so that the base membrane is gradually sent out from the extraction tank 3; in actual application, the extraction tank 3 is filled with an extractant, and the wetting agent on the surface of the hollow fiber base membrane entering the tank and part of the wetting agent in the membrane pores are continuously extracted and removed to obtain membrane fibers after extraction treatment.

[0042] Among them, the length of the extraction tank 3 in the base membrane conveying direction is adapted to the theoretical extraction time of the base membrane and the feeding speed of the feeding unit to ensure that the base membrane is immersed in the extractant for a sufficient time; in this embodiment, based on the feeding speed of the base membrane by the feeding unit being maintained at about 1m / min, the length of the extraction tank 3 in the base membrane conveying direction is 0.5m to ensure that the base membrane is immersed in the extractant for about 30s, which is consistent with the theoretical extraction time.

[0043] The drying tunnel 4 is arranged above the discharge end of the extraction tank 3, and includes a drying cylinder with a vertical channel, and the drying cylinder and the membrane filaments extending vertically upward from the discharge roller 302 are arranged in a central position, so that the membrane filament ends after extraction treatment extend from bottom to top along the central axis direction of the drying cylinder; the drying cylinder specifically includes a cylindrical cylinder body, on the inner wall of which a spirally arranged electric heating tube and a temperature sensor are fixed from bottom to top, and a temperature controller is provided on the outer wall of the cylinder, and the temperature controller is electrically connected to the electric heating wire and the temperature sensor respectively, so as to adjust the power-on heating time of the electric heating wire through the temperature controller, so that the drying temperature in the drying cylinder is consistent with the set temperature, ensuring that the extractant remaining on the surface of the membrane filaments after extraction treatment is completely removed by drying after passing through the drying tunnel 4; preferably, in this embodiment, the length of the drying tunnel 4 is set to 1m, and the drying temperature therein is adjustable between room temperature and 80°C.

[0044] A first feeding roller 401 is rotatably arranged above the top opening of the drying cylinder through a roller frame, and the axial direction of the first feeding roller 401 is the same as the axial direction of the discharging roller 302, so that the base film end derived from the extraction tank 3 of the drying cylinder is vertically conveyed upward from the bottom of the drying tunnel 4, and then sent out from the top opening of the drying tunnel 4, and passes around the first feeding roller 401 clockwise to enter the next unit, namely the coating unit.

[0045] The coating unit is arranged at a position adjacent to the upper part of the drying tunnel 4 , and comprises a liquid tank 5 , a coating head 6 and a low-temperature cooling liquid circulation system 7 .

[0046] The liquid tank 5 is a tank body with a double-layer wall and a tapered bottom end; wherein, a closed sealed chamber is formed between the double-layer walls of the tank body, and a spirally arranged condenser tube is arranged in the chamber, and both ends of the condenser tube extend to the outside of the liquid tank 5 through holes opened on the outer wall of the liquid tank 5; wherein, the end of the condenser tube located on the upper side of the liquid tank 5 serves as the liquid outlet end, and the end of the condenser tube located on the lower side of the liquid tank 5 serves as the liquid inlet end;

[0047] The coating head 6 is arranged directly below the liquid tank 5. It is a cylindrical tube body with a double-layer wall. There is a closed sealed chamber between the double-layer walls of the tube body. A spirally arranged condenser is arranged in the chamber. Both ends of the condenser extend to the outside of the coating head 6 through holes opened on the outer wall of the coating head 6; wherein, the end of the condenser located on the upper side of the coating head 6 serves as the liquid outlet end, and the end of the condenser located on the lower side of the coating head 6 serves as the liquid inlet end; the top end of the coating head 6 is inserted and fixed on the bottom end of the tapered end of the liquid tank 5, so that the liquid tank 5 is communicated with the inner cavity of the coating head 6.

[0048] Among them, the aperture of the central through hole of the coating head 6 is adapted to the diameter of the base membrane; preferably, the aperture of the central through hole of the coating head 6 is 1.01 to 1.5 times the diameter of the hollow fiber base membrane, and this aperture range can be matched with a coating liquid with a certain viscosity. During the coating process of the membrane filament, the coating liquid will not drip from the coating head 6; in this embodiment, based on the diameter of the base membrane filament being 2 mm, the aperture of the central through hole of the coating head 6 is set to 2.05 mm to 2.1 mm.

[0049] The coolant pumping end of the low-temperature coolant circulation system 7 is connected to the liquid inlet end on the liquid tank 5 and the coating head 6 through pipelines, and the coolant reflux end is connected to the liquid outlet end on the liquid tank 5 and the coating head 6 through pipelines, so that the low-temperature coolant circulation system 7 is used to circulate and cool the coolant in the liquid tank 5 and the coating head 6 to ensure that the temperature of the coolant circulating back and forth in the condenser tubes of the liquid tank 5 and the coating head 6 is adjusted at -50℃~-10℃.

[0050] As a preferred technical solution of this embodiment, the outer walls of the liquid tank 5 and the coating head 6 are coated with a thermal insulation layer, which is specifically a foamed ceramic layer.

[0051] A second feeding roller 501 is also rotatably arranged above the liquid tank 5 through a roller frame, and is arranged side by side with the first feeding roller 401 at the same height, and the two are fixed to the top of the curing reaction tunnel furnace 8 through the wheel frame; the base film wrapped around the first feeding roller 401 is wrapped around the second feeding roller 501 clockwise, so as to be vertically downwardly introduced into the liquid tank 5 and the coating head 6 in sequence, so as to evenly coat the liquid on the surface of the base film.

[0052] The curing unit includes a first curing tunnel furnace 8 and a second curing tunnel furnace 9, which are arranged at an upper and lower interval below the coating head 6; the first curing tunnel furnace 8 and the second curing tunnel furnace 9 both include a drying drum with a vertical channel, and the drying drum specifically includes a cylindrical cylinder, on the inner wall of the cylinder, a spirally arranged electric heating tube and a temperature sensor are fixed from bottom to top, and a temperature controller is provided on the outer wall of the cylinder, and the temperature controller is electrically connected to the electric heating wire and the temperature sensor respectively, so as to adjust the power-on heating time of the electric heating wire through the temperature controller, so that the drying temperature in the drying drum is consistent with the set temperature, ensuring that the membrane filaments after coating treatment first pass through the first curing tunnel furnace 8 to remove the solvent, and then pass through the second curing tunnel furnace 9 to cure the coating liquid to form a PDMS hollow fiber composite membrane; preferably, in this embodiment, the length of the first curing tunnel furnace 8 is set to 0.5m, and its internal drying temperature is adjustable at 25-80°C; the length of the second curing tunnel furnace 9 is set to 1m, and its internal drying temperature is adjustable at 25-200°C.

[0053] A third feeding roller 801 is provided below the second curing tunnel furnace 9 through a roller frame for rolling, so that the membrane wire end derived from the coating head 6 is transported vertically downward, passes through the first curing tunnel furnace 8 and the second curing tunnel furnace 9 in turn, and then is wound around the third feeding roller 801 counterclockwise to continue to be transported horizontally to the next unit, namely the receiving unit.

[0054] The material receiving unit includes a wire receiving box 10, in which a second rotating drum 1001 controlled by a material receiving motor is provided. A material receiving port is provided on the wall of the box body which is parallel to the axis of the second rotating drum 1001 and faces the curing unit. The material receiving port is preferably arranged on the lower side of the wire receiving box 10. A material receiving roller 901 is also provided on the inner side of the wire receiving box 10 and close to the material receiving port via a roller frame. In actual application, the ends of the composite membrane wires processed by the curing unit are successively wound counterclockwise around the material receiving roller 901 and the wire receiving drum pre-mounted and fixed on the second rotating drum 1001. The material receiving motor controls the second rotating drum 1001 to drive the wire receiving drum to rotate synchronously, so that the PDMS hollow fiber composite membrane formed by the processing of each unit in turn is gradually wound into a roll on the wire receiving drum, thereby completing the material receiving of the composite membrane.

[0055] Example 2

[0056] A method for continuously preparing a PDMS hollow fiber composite membrane I using the device for continuously preparing a PDMS hollow fiber composite membrane of Example 1, wherein the specific implementation steps are as follows:

[0057] S1. Soak the PSF hollow fiber membrane in a 30 wt% glycerol aqueous solution for 24 h, and then dry it in a vacuum oven at 60 °C for 24 h; install the dried membrane in the support layer hollow fiber membrane supply unit, and the membrane front section is Figure 1 As shown, it is threaded on each unit and finally fixed on the wire collection drum;

[0058] S2, the extraction tank is filled with distilled water, the membrane fiber path is 17 cm, and the extraction time is about 10 seconds; the temperature in the drying tunnel 8 is set to 80°C;

[0059] S3, vinyl terminated PDMS, hydrogenated silicone oil, Perkin catalyst, inhibitor, and n-hexane are mixed in a ratio of 5:1:0.5:0.2:54 to prepare a 30wt% PDMS coating liquid; the prepared coating liquid is injected into the liquid tank; the low-temperature cooling liquid circulation system 7 is started, and the cooling temperature of the cooling liquid is -20°C; wherein the inhibitor adopts the PC-611 inhibitor produced by Shanghai Neutron Star Chemical Technology Co., Ltd., and the following Examples 3 and 4 are the same;

[0060] S4, setting the temperature in the first curing tunnel furnace 8 to 60° C., and setting the temperature in the second curing tunnel furnace 9 to 60° C.;

[0061] S5. Start the feeding motor and the receiving motor in sequence. The feeding motor drives the reel to feed the wire at a speed of 1 m / min. The receiving motor drives the wire collecting reel to collect the wire at a speed of 1 m / min, so as to realize the continuous preparation of the PDMS hollow fiber composite membrane.

[0062] The PDMS composite membrane obtained after winding on the above-mentioned winding drum was used for CO2 / N2 and O2 / N2 separation. The CO2 / N2 and O2 / N2 separation coefficients of the composite membrane were measured to be 10.1 and 2.15 at a permeation side pressure of 200KPa, respectively. The CO2 permeation flux was 579GPU, and the O2 permeation flux was 123GPU.

[0063] Example 3

[0064] A method for continuously preparing a PDMS hollow fiber composite membrane II using the device for continuously preparing a PDMS hollow fiber composite membrane of Example 1, wherein the specific implementation steps are as follows:

[0065] S1. Soak the PSF hollow fiber membrane in a 30 wt% glycerol aqueous solution for 24 h, and then dry it in a vacuum oven at 60 °C for 24 h; install the dried membrane in the support layer hollow fiber membrane supply unit, and the membrane front section is Figure 1 As shown, it is threaded on each unit and finally fixed on the wire collection drum;

[0066] S2, replace the extraction tank and fill it with distilled water, the membrane fiber path is 8cm, the extraction time is about 5s; the temperature in the drying tunnel 8 is set to 80°C;

[0067] S3, vinyl terminated PDMS, hydrogenated silicone oil, Perkin catalyst, inhibitor, and n-hexane are mixed in a ratio of 5:1:0.5:0.2:0 to prepare a 100 wt% PDMS coating liquid; inject the prepared coating liquid into the liquid tank; start the low-temperature cooling liquid circulation system 7, and the cooling temperature of the cooling liquid is -20°C;

[0068] S4, setting the temperature in the first curing tunnel furnace 8 to 60° C., and setting the temperature in the second curing tunnel furnace 9 to 60° C.;

[0069] S5. Start the feeding motor and the receiving motor in sequence. The feeding motor drives the winding drum to feed the wire at a speed of 2 m / min. The receiving motor drives the wire collecting drum to collect the wire at a speed of 2 m / min, so as to realize the continuous preparation of the PDMS hollow fiber composite membrane.

[0070] The PDMS composite membrane obtained after winding on the above-mentioned winding drum was used for CO2 / N2 separation. The CO2 / N2 and O2 / N2 separation coefficients of the composite membrane were measured to be 10.5 and 2.18 at a permeation side pressure of 200 KPa, respectively. The CO2 permeation flux was 64 GPU, and the O2 permeation flux was 13 GPU.

[0071] Example 4

[0072] A method for continuously preparing a PDMS hollow fiber composite membrane III using the device for continuously preparing a PDMS hollow fiber composite membrane of Example 1, wherein the specific implementation steps are as follows:

[0073] S1. Soak the PAN hollow fiber membrane in a 30 wt% paraffin aqueous solution for 24 h, and then dry it in a vacuum oven at 60 °C for 24 h; install the dried membrane in the support layer hollow fiber membrane supply unit, and the membrane front section is Figure 1 As shown, it is threaded on each unit and finally fixed on the wire collection drum;

[0074] S2, the extraction tank is filled with distilled water, the membrane fiber path is 8 cm, and the extraction time is about 5 seconds; the temperature in the drying tunnel 8 is set to 60°C;

[0075] S3, vinyl terminated PDMS, hydrogenated silicone oil, Perkin catalyst, inhibitor, and n-hexane are mixed in a ratio of 5:1:0.5:0.2:114 to prepare a 5wt% PDMS coating liquid; inject the prepared coating liquid into the liquid tank; start the low-temperature cooling liquid circulation system 7, and the cooling temperature of the cooling liquid is -30°C;

[0076] S4, setting the temperature in the first curing tunnel furnace 8 to 60° C., and setting the temperature in the second curing tunnel furnace 9 to 60° C.;

[0077] S5. Start the feeding motor and the receiving motor in sequence. The feeding motor drives the reel to feed the wire at a speed of 0.5 m / min. The receiving motor drives the wire collecting reel to collect the wire at a speed of 0.5 m / min, so as to realize the continuous preparation of the PDMS hollow fiber composite membrane.

[0078] The PDMS composite membrane obtained after winding on the above-mentioned winding drum was used for CO2 / N2 separation. The CO2 / N2 and O2 / N2 separation coefficients of the composite membrane were measured to be 9.6 and 1.9 at a permeation side pressure of 200 KPa. The CO2 permeation flux was 2974 GPU, and the O2 permeation flux was 619 GPU.

[0079] It can be proved through the above-mentioned Examples 2 to 4 that the above-mentioned method for continuously preparing PDMS hollow fiber composite membranes and the preparation device thereof of the present invention can not only realize the continuous preparation of hollow fiber composite membranes, but also the prepared hollow fiber composite membranes have good permeation flux and have good use effect in gas separation performance.

Claims

1. A device for continuously preparing PDMS hollow fiber composite membranes, characterized in that: It includes a feeding unit, a wetting agent extraction unit, a coating unit, a curing unit and a receiving unit; wherein, The feeding unit comprises a feeding box (1), in which a first rotating cylinder controlled by a feeding motor is arranged, and a discharge port is provided on a wall surface of the box body parallel to the axis of the first rotating cylinder; The wetting agent extraction unit comprises an extraction tank (3) and a drying tunnel (4) which are sequentially arranged along the base film conveying direction; the extraction tank (3) is an open strip tank, and a feed roller (301) is respectively arranged at the slot opening and the slot bottom position close to the feed box (1), and a discharge roller (302) is respectively arranged at the slot opening and the slot bottom position away from the feed box (1); the drying tunnel (4) is arranged above the discharge roller (302), and comprises a drying cylinder with a vertical channel, and a first feed roller (401) is arranged above the drying cylinder; The coating unit comprises a liquid tank (5), a coating head (6) and a low-temperature circulation system (7); the liquid tank (5) is an open tank body with a condenser arranged spirally on the wall, and its bottom end is a conical opening end; the coating head (6) is a tank body with a condenser arranged spirally on the wall, and the inner diameter of which is adapted to the outer diameter of the film to be coated; the coating head (6) is connected to the bottom end of the liquid tank (5), and the inner cavities of the two are connected; the low-temperature circulation system (7) is connected to the condenser of the liquid tank (5) and the coating head (6) through pipelines respectively, so as to circulate the low-temperature cooling liquid; a second feeding roller (501) arranged side by side with the first feeding roller (401) is provided above the liquid tank 5; The curing unit comprises a first curing tunnel furnace (8) and a second curing tunnel furnace (9), both of which comprise a drying cylinder having a vertical channel and are arranged at an upper and lower interval below the coating head (6); a third feeding roller (801) is arranged below the second curing tunnel furnace (9); The material receiving unit comprises a wire receiving box (10) in which a second rotating cylinder controlled by a feeding motor is arranged, a material receiving opening is provided on the box wall parallel to the axis of the second rotating cylinder and facing the curing unit, and a material receiving roller (901) is provided adjacent to the material receiving opening.

2. The device for continuously preparing PDMS hollow fiber composite membrane according to claim 1, characterized in that: A tension regulator (2) is also provided at the discharge port of the feed box (1), which is composed of a tension testing device and a tension control device; the detection end of the tension testing device of the tension regulator (2) contacts the base film extending from the discharge port to monitor the tension of the film filament passing through its detection end; the tension control device is respectively connected to the tension testing device and the feed motor, so that the tension control device adjusts the rotation speed of the feed motor based on the real-time tension test value.

3. The device for continuously preparing PDMS hollow fiber composite membrane according to claim 1, characterized in that: In the feeding unit, the conveying speed of the first rotating drum is adjustable between 0.5m / min and 5m / min; in the wetting agent extraction unit, the length of the extraction tank (3) in the base membrane conveying direction is adapted to the theoretical extraction time of the base membrane and the feeding speed of the feeding unit; in the coating unit, the central aperture of the coating head (6) is 1.01 to 1.5 times the diameter of the hollow fiber base membrane; in the curing unit, the length of the first curing tunnel furnace (8) is 0.5m to 2m, and its internal temperature is adjustable between 25°C and 80°C; the length of the second curing tunnel furnace (9) is 1m to 5m, and its internal temperature is adjustable between 25°C and 200°C; in the receiving unit, the conveying speed of the second rotating drum is adjustable between 0.5m / min and 5m / min.

4. The device for continuously preparing a PDMS hollow fiber composite membrane according to claim 1, characterized in that: The outer walls of the liquid tank (5) and the coating head (6) are both coated with a heat-insulating layer.

5. A method for continuously preparing a PDMS hollow fiber composite membrane using the device for continuously preparing a PDMS hollow fiber composite membrane according to any one of claims 1 to 4, comprising the following steps: S1, soaking the hollow fiber base membrane in a wetting agent for pretreatment, and then winding it on a reel after drying and dehydration; the reel is installed on a first rotating drum, and the base membrane end thereon is sequentially passed through and wound on the rollers of each unit, and finally wound and fixed on a receiving drum; S2, filling the extraction tank (3) with extraction liquid, and adjusting the feeding speed of the feeding unit so that the time for the base film to pass through the membrane fiber path in the extraction tank meets the extraction time; setting the drying temperature of the drying tunnel (4); S3, preparing the coating liquid: after the polydimethylsiloxane, the catalyst, the inhibitor and the solvent are evenly mixed, the cross-linking agent is added and mixed evenly and degassed; the prepared coating liquid is poured into the liquid tank (4), and the low-temperature cooling liquid circulation system (7) is turned on to keep the coating liquid in the liquid tank (5) at a low temperature; S4, respectively setting the drying temperature of the first curing reaction tunnel furnace (8) and the curing temperature of the second curing reaction tunnel furnace (9); S5. Start the feeding motor and the receiving motor in sequence to realize the continuous preparation of the PDMS hollow fiber composite membrane.

6. The method for continuously preparing the PDMS hollow fiber composite membrane according to claim 4, characterized in that: In step S1, the hollow fiber-based membrane is a polyvinylidene fluoride membrane, a polysulfone membrane, a polyacrylonitrile membrane, a polypropylene membrane, a polyethylene membrane, a polytetrafluoroethylene membrane, a polyethersulfone membrane, a sulfonated polyethersulfone membrane, a polyimide membrane, or a polyetherimide or polyetheretherketone membrane.

7. The continuous preparation method of PDMS hollow fiber composite membrane according to claim 1, characterized in that: In step S2, the extraction liquid is water, ethanol, methanol, isopropanol, petroleum ether or n-hexane, and the extraction time is 1 second to 30 seconds; the drying temperature of the drying tunnel (4) is set to 25°C to 80°C.

8. The method for continuously preparing a PDMS hollow fiber composite membrane according to claim 1, characterized in that: In step S3, the mass ratio of polydimethylsiloxane, crosslinking agent, catalyst and inhibitor is (1-20):1:(0.01-0.5):(0.002-0.5); polydimethylsiloxane is polydimethylsiloxane with end-capping vinyl group or polydimethylsiloxane with side group being vinyl group, and its molecular weight is 200g / mol-100000g / mol; the crosslinking agent is hydrogenated silicone oil, the catalyst is platinum catalyst, the inhibitor is acetylene alcohol, and the solvent is n-hexane, n-heptane, chloroform, dichloromethane or toluene; the amount of solvent added satisfies that the mass fraction of polydimethylsiloxane, crosslinking agent, catalyst and inhibitor in the coating liquid is 1wt.%-100wt.%.

9. The continuous preparation method of PDMS hollow fiber composite membrane according to claim 1, characterized in that: In step S4, the drying temperature of the first curing reaction tunnel furnace (8) is set to 25°C to 80°C; and the curing temperature of the second curing reaction tunnel furnace (9) is set to 25°C to 200°C.

10. The continuous preparation method of PDMS hollow fiber composite membrane according to claim 1, characterized in that: In step S5, the feeding motor supplies the base film at a feeding speed of 0.5 m / min to 5 m / min, and the winding motor drives the winding drum to wind the composite film wire at a winding speed of 0.5 m / min to 5 m / min.

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