Scaling-up the production of nanosized SiO2-particles in a double diffusion flame aerosol reactor

Synthesis of nanophase silica (SiO2) from hexamethyldisiloxane (HMDS) oxidation in a co-flow diffusion flame reactor at atmospheric pressure is investigated focusing on high production rates of powder. A new experimental set-up is introduced, including a diffusion burner which is operated with a ring-shape double diffusion flame. Significantly high HMDS concentrations are used resulting in SiO2 production rates of up to 130 g/h. Deposition of silica powder on the burner face is eliminated by the design of a special diffusion burner and higher collection rates are achieved using a baghouse filter. The specific surface area and the product powder composition are analyzed. Carbon black coated silica particles were produced at high production rates (130 g/h) at low oxygen flow rates or using a mixture of nitrogen and oxygen as oxidant. The size of the product particles was controlled in the range of 15-170 nm.