Method for quickly preparing nano thermal insulation material by supercritical drying

Abstract

The invention discloses a method for quickly preparing a nano thermal insulation material by supercritical drying. The method combines liquid preparation, dipping, gelation and drying. After fiber felt rolls are directly immersed in a drying kettle for molding and solidification, the fiber felt rolls are directly heated to dry with supercritical methanol or ethanol, so as to achieve complete sealing to prepare the nano thermal insulation material. The method omits the curing and molding step of fiber felt, injects gel solution into the drying kettle, uses the adsorption performance of the fiber felt to remove the excess gel, and directly performs supercritical drying after gelation. The method has simple process, is easy to realize complete automation, saves much equipment investment, at the same time avoids a large amount of organic solvent volatilization and personnel contact with volatiles, and the waste heat recovery in the production process can save energy to the greatest extent.

Description

Technical field [0001] The invention relates to a method for quickly preparing nano thermal insulation materials by supercritical drying. Background technique [0002] In the preparation process of silicon oxide nano heat insulation material, the currently known preparation method of nano heat insulation material usually adopts aerogel and fiber mat fiber composite, and then adds spacers and soaks and ages, or performs hydrophobic modification process again, and then performs Supercritical carbon dioxide drying. The commonly used method for compounding fiber felt and gel liquid is gel tank whole roll soaking method, or unwinding-dipping-heating curing-adding septum winding method. [0003] After immersing the fiber web by the gel tank dipping method, a large amount of gel liquid forms a bulk aerogel around the fiber felt, which is broken and dropped after rewinding and adding a septum, forming a large amount of waste gel, and the operation engineering A large number of people are...

AI Technical Summary

Problems solved by technology

Among them, the supercritical carbon dioxide drying method needs to continuously heat, cool, and compress carbon dioxide. The equipment is complicated, the energy consumption is high, the time for pressurization, replacement drying, and pressure relief is long, and the requirements for operators are high. It is difficult to achieve automation, and The water in the wet gel felt is not easily extracted by carbon dioxide, thus greatly increasing the production cost of nano-insulation materials

However, the preparation of nano-insulation materials by normal pressure drying, due to pore shrinkage and gel cracking during the drying process, the properties of the prepared nano-insulation materials cannot meet the requirements of use, and the drying time is long and the recovery rate of the solution is low, so gradually Be eliminated

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