Detection of NaOH vapor in glass furnaces using excimer laser photofragmentation spectroscopy

Abstract

Corrosion of refractory silica brick and problematic air quality issues surrounding particulate emissions are two important glass manufacturing problem areas that have been tied to volatilized sodium and its transport throughout the melt tank. Although there is some understanding of the relationship between tank operating conditions and tank atmosphere sodium levels, until recently direct quantitative measurements of sodium levels have been limited to extractive sampling methods followed by laboratory analysis. Excimer laser induced fragmentation (ELIF) fluorescence spectroscopy is a technique that permits the measurement of volatilized NaOH in high temperature environments on a time scale of less than one second. The development of this method and the construction of field portable instrumentation for glass furnace applications are reported. Characteristics of the method are outlined, including equipment configuration, detection sensitivity, and calibration methodology. Results from a small batch furnace and two com mercial float glass furnaces are used to show the potential impact and the existing limitations of the ELIF approach for real time NaOH vapor monitoring. This method is shown to be effective in industrial settings and presents an approach to optimize burner settings.