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Preparation method of teflon hollow fiber membrane for membrane distillation

A technology of polytetrafluoroethylene and fiber membranes, which is applied in the field of preparation of polytetrafluoroethylene hollow fiber membranes for membrane distillation, and can solve the problems of PET fiber braided tubes being easily wetted by water, the quality of water produced by membrane distillation, and high equipment requirements. problem, to achieve the effect of saving the wrapping link, reducing the cost of materials, and good hydrophobic performance

Inactive Publication Date: 2013-02-27
ZHEJIANG SCI-TECH UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Patent CN102284251A prepares polytetrafluoroethylene hollow fiber membranes by continuously wrapping polytetrafluoroethylene flat membranes on polyester (PET) fiber braided tube supports, but this method uses PET fiber braided tubes with poor hydrophobicity as support During the long-term high-temperature distillation process, the PET fiber braided tube is easily wetted by water, which leads to a great decrease in the quality of membrane distillation water.
The patent (publication number: CN202129031U) adopts the method of wrapping the outer wall of a polytetrafluoroethylene hollow fiber support body with a pore size range of 0.5-2 μm and a microporous PTFE film layer with a pore size range of 0.02-0.5 μm to prepare a PTFE hollow fiber Membranes are mainly used for microfiltration membrane separation and the process is complex, requiring high equipment

Method used

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  • Preparation method of teflon hollow fiber membrane for membrane distillation
  • Preparation method of teflon hollow fiber membrane for membrane distillation

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0026] a. Mixing: Select polytetrafluoroethylene dispersed resin powder with a molecular weight of 2 million, mix the polytetrafluoroethylene resin powder and liquid paraffin evenly at a weight ratio of 1:0.22, and let stand at 20°C for 80 hours to make the resin powder and liquid paraffin Mix well, and sieve out larger powder particles;

[0027] b. Compaction and extrusion: The mixed polytetrafluoroethylene material is pressed into a cylindrical blank on a compactor, and the blank is extruded at 100°C through a pusher with a cone die and a die. Hollow pipe, the cone angle θ of the cone die is 35°, the length-to-diameter ratio of the die is 11, and the extrusion speed is 100 cm / min;

[0028] c. Longitudinal stretching and sintering: stretch the treated polytetrafluoroethylene hollow tube longitudinally in an oven to form a polytetrafluoroethylene hollow fiber membrane, the stretching ratio is 0.5 times, and the oven temperature is 250°C;

[0029] d. The stretched polytetra...

Embodiment 2

[0032]a. Mixing: Select polytetrafluoroethylene dispersed resin powder with a molecular weight of 10 million, mix polytetrafluoroethylene resin powder and petroleum ether in a weight ratio of 1:0.40, and stand at 40°C for 60 hours to make the resin powder and petroleum ether Mix well, and sieve out larger powder particles;

[0033] b. Compaction and extrusion: The mixed polytetrafluoroethylene material is pressed into a cylindrical blank on a compactor, and the blank is extruded at 200°C through a pusher with a cone die and a die. Hollow tube, the extrusion speed is 300 cm / min, the cone angle θ of the cone die is 60°, and the length-to-diameter ratio of the die is 20;

[0034] c. Longitudinal stretching and sintering: longitudinally stretch the treated PTFE hollow tube in an oven to form a PTFE hollow fiber membrane, the stretching ratio is 2 times, and the oven temperature is 320°C;

[0035] d. The stretched polytetrafluoroethylene hollow fiber membrane was sintered and h...

Embodiment 3

[0038] a. Mixing: Select polytetrafluoroethylene dispersed resin powder with a molecular weight of 8 million, mix polytetrafluoroethylene resin powder and kerosene at a weight ratio of 1:0.30, and let stand at 30°C for 75 hours to fully mix the resin powder and kerosene , sieve to remove larger powder particles;

[0039] b. Compaction and extrusion: The mixed polytetrafluoroethylene material is pressed into a cylindrical blank on a compactor, and the blank is extruded at 150°C through a pusher with a cone die and a die. Hollow tube, the extrusion speed is 240 cm / min, the cone angle θ of the cone die is 45°, and the length-to-diameter ratio of the die is 15;

[0040] c. Longitudinal stretching and sintering: longitudinally stretch the treated PTFE hollow tube in an oven to form a PTFE hollow fiber membrane, the stretching ratio is 1 times, and the oven temperature is 300°C;

[0041] d. The stretched polytetrafluoroethylene hollow fiber membrane was sintered and heat-set in ...

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Abstract

The invention discloses a preparation method of a teflon hollow fiber membrane for membrane distillation, which comprises the following steps of: mixing teflon dispersion powder and a extruding-aid agent, pressing a blank, extruding the blank into a teflon hollow tube through a pushing and pressing machine with a cone mould and a mouth mould, and performing longitudinal stretch, sintering and heat setting on the teflon hollow tube in a drying oven to obtain the teflon hollow fiber membrane. The processed teflon hollow fiber membrane is in an asymmetric structure, the mean pore size of an outer layer is 0.10-1.0 micrometer, the mean pore size of an inner layer is 5.0-20 micrometers, the wall thickness is 0.1-0.5 millimeter, the bubble point pressure is 0.5-2.0 kgf / square centimeter, and the water resistance pressure is 1.5-6kgf / square micrometer. The invention is mainly used for the membrane distillation separation process, and can be applied to the fields of sea water desalination, industrial wastewater treatment, cryoconcentration of food and biological products, and the like.

Description

technical field [0001] The invention relates to a preparation method of a hollow fiber membrane, in particular to a preparation method of a polytetrafluoroethylene hollow fiber membrane for membrane distillation. Background technique [0002] Membrane distillation technology is a new type of membrane separation technology that uses the difference in vapor pressure on both sides of a hydrophobic microporous membrane as the driving force for mass transfer. Because membrane distillation technology can repel non-volatile substances in the solution (such as ions, macromolecules and solid particles, etc.), the operating pressure is lower than that of reverse osmosis, the equipment is simple, the requirements for raw water quality are low, and only water vapor passes through the membrane pores. The produced water has the advantages of high purity, which can be used in seawater desalination, deep reuse treatment of industrial wastewater, concentration and crystallization of food and...

Claims

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Application Information

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IPC IPC(8): B01D71/36B01D67/00B01D69/08
Inventor 朱海霖郭玉海王峰张华鹏李玖明陈建勇唐红艳
Owner ZHEJIANG SCI-TECH UNIV
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