Design and manufacturing of supercritical drying autoclave for aerogel production

Abstract

This article will address autoclave design considerations andmanufacturing working with high pressure low temperaturesupercritical drying technique to produce silica aerogel. The designelects carbon dioxide as a supercritical fluid (31.7 oC and 72.3 bar).Both temperature and pressure have independently controllingfacility through present design. The autoclave was light weight (4.5kg) and factory-made from stainless steel. It contains a high pressurewindow for monitoring both transfer carbon dioxide gas to liquidcarbon dioxide and watching supercritical drying via aerogelpreparation process. In this work aerogel samples were prepared andthe true apparent densities, total pore volume and pore sizedistribution, BET surface area, spectroscopic refractive index,structure and thermal properties have been systematicallyinvestigated characteristic.