SIMULATION OF A TECHNOLOGICAL SCHEME IN OBTAINING HEAT-INSULATING MATERIALS ON THE BASIS OF AIROGELS

Abstract

The analysis of technologies for obtaining inorganic aerogels based on silicon dioxide as heat-insulating materials has been carried out. The description of the process of supercritical drying for obtaining highly efficient heat-insulating materials based on inorganic aerogels is given, the main technological parameters are given. The technological scheme of the main stage of obtaining aerogels is presented and described - the process of supercritical drying of an industrial plant located in LLC Niagara, Shchelkovo, in the development of which the authors took part (there is a patent). For this production, a mathematical model has been developed using the CHEMCAD software package, which makes it possible to build material and heat balances of both individual devices and the technological scheme as a whole. The technological scheme of the drying process in the environment of supercritical carbon dioxide includes the following devices: high-pressure autoclaves (70 l), compressor, separator, heat exchanger, refrigerant pump, and condenser. The article presents the basic equations for calculating the operation parameters of the above equipment (power, enthalpy, pressure, etc.), as well as the equations used in calculating economic costs (for raw materials, electricity, etc.). Calculations were carried out according to the equations of the model built in the CHEMCAD environment and the influence of various parameters on the energy and resource saving of the process was studied. The effect of isopropyl alcohol on the consumption of carbon dioxide was calculated. A dependence of the temperature after throttling the flow of supercritical carbon dioxide on the content of the solvent isopropyl alcohol in it is constructed, illustrating the possibility of reducing the amount of heat supplied at the initial stages of the drying process. Based on the data obtained, an analysis of the energy and economic costs of the supercritical drying process was carried out. On the basis of a mathematical model, an energy- and resource-efficient method of technological design of the supercritical drying process is determined. A decrease in the energy and economic costs of the technological scheme using heat after compression has been established.