Design and manufacturing of supercritical drying autoclave for aerogel production

Abstract

This article will address autoclave design considerations and manufacturing working with high pressure low temperature supercritical drying technique to produce silica aerogel. The design elects carbon dioxide as a supercritical fluid (31.7 oC and 72.3 bar). Both temperature and pressure have independently controlling facility through present design. The autoclave was light weight (4.5 kg) and factory-made from stainless steel. It contains a high pressure window for monitoring both transfer carbon dioxide gas to liquid carbon dioxide and watching supercritical drying via aerogel preparation process. In this work aerogel samples were prepared and the true apparent densities, total pore volume and pore size distribution, BET surface area, spectroscopic refractive index, structure and thermal properties have been systematically investigated characteristic.