Numerical simulation of the synthesis of titania-silica composite nanoparticles in plasmachemical reactor Free

In this work an original numerical investigation of the synthesis of titania-silica composite nanoparticles in the working zone of plasmachemical reactor has been performed. Single-stage chloride method of synthesis of sought composite powder has been modeled based on successive oxidation of titanium tetrachloride and silicon tetrachoride. At the top of the reactor TiCl₄ vapours are injected, then downstream gas-phase conversion of the titanium tetrachloride and formation of titania particles as well as their growth caused by coagulation and surface TiCl₄ conversion proceed. The silica vapors arise in the region of mixing of SiCl₄ vapors and high-temperature mainstream, the vapors are condensed upon titania particles, thus forming silica shells. In addition, an increase of shell thickness is also caused by surface conversion of SiCl₄ vapors. Nitrogen is used as plasma-forming gas, both TiCl₄ and SiCl₄ vapours are separately premixed with air oxygen prior to be supplied to the plasmachemical reactor. Since there is a scarce of information about accurate values of some parameters of physico-mathematical model, the numerical investigation has been carried out at variable values of corresponding parameters. It is necessary to gain the insight of the physical and chemical phenomena accompanying the synthesis of composite particles in the reactor and to verify the used model as well.