Blended low-thermal-conductivity film containing nanoscale low-thermal-conductivity material and high polymer as well as preparation method and application of blended low-thermal-conductivity film

Abstract

The invention discloses a blended low-thermal-conductivity film containing a nanoscale low-thermal-conductivity material and a high polymer as well as a preparation method and application of the blended low-thermal-conductivity film, wherein the blended low-thermal-conductivity film takes a hydrophobic or hydrophobically modified high polymer material as a main body, and the nanoscale low-thermal-conductivity material is added; based on the mass percentage, the nano-scale low-thermal-conductivity material accounts for 0-10% of the blended low-thermal-conductivity film and is not 0, the pore size distribution of the blended low-thermal-conductivity film is narrow and uniform, the pore size is 0.3 [mu]m-0.5 [mu]m, and the porosity is 30%-80%. By adding the nanoscale low-thermal-conductivity material into the film for film distillation and utilizing the unique performance of the nanoscale low-thermal-conductivity material, the flux and the heat utilization rate of the film distillation and related film processes are greatly improved. The prepared film has the advantages of uniform pore size distribution, excellent air permeability, stable operation and low thermal conductivity, is especially suitable for the film distillation process, increases the temperature difference and vapor pressure difference of the two sides of the film, improves the mass transfer efficiency, reduces the MD heat loss, improves the thermal efficiency of the film distillation process, and optimizes the mass transfer efficiency.

Description

technical field [0001] The invention belongs to the technical field of polymer material science and membrane separation, and relates to material separation, concentration, purification and other technologies, in particular to a blended low thermal conductivity film containing nano-scale low thermal conductivity materials and high polymers and its preparation method and application. Background technique [0002] Due to the increasing demand for fresh water around the world, membrane distillation (Membrane Distillation, referred to as MD) has attracted widespread attention of researchers. MD theoretically has a retention rate of up to 100%. It is an efficient membrane separation technology that can effectively utilize cheap energy such as solar energy, geothermal energy, industrial waste heat, and seawater waste heat. The operating pressure is much lower than membrane separation such as nanofiltration and reverse osmosis. process, the separation mechanism allows only volatile ...

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Problems solved by technology

[0004] Although membrane distillation can effectively utilize cheap heat sources, its thermal efficiency is far lower than other thermal concentration processes. Therefore, improving the thermal efficiency of membrane distillation has long-term significance for reducing energy consumption of membrane distillation and promoting the industrialization of membrane distillation.

Patent CN200410037319 discloses a method for improving the membrane distillation process while increasing membrane distillation flux and thermal efficiency, but only increases the complexity of membrane modules and equipment from the perspective of technology, and the degree of improvement is limited

Patent CN101829502A uses airgel composite membrane or blending to prepare hydrophobic microporous membrane material for membrane distillation, which improves the flux and thermal efficiency of membrane distillation, but the cost of airgel material is high, and industrialization may be affected

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