Residence time distribution studies for flow characterization and process improvement of an industrial solar glass production unit using radiotracer

The efficiency, throughput and quality of glass sheets produced in a solar glass production unit (SGPU) are directly influenced by the flow dynamics of molten glass within furnace and forehearth. The residence time distribution (RTD) measurement is an experimental method to quantify the flow parameters of the molten glass and characterization of their mixing patterns. In the present study, a RTD measurement using La-140 as radiotracer was carried out in SGPU. From the radiotracer data, time of first appearance of molten glass, fraction of molten glass distribution on either side of furnace and forehearth, mean residence time (MRT), dead volume and homogenization time were estimated. The RTD curve of furnace indicated flow malfunction channelling in the furnace of SGPU. This flow maldistribution identified was one of the major causes of the poor quality of glass sheets produced in the SGPU. Further, to estimate the fraction of molten glass in two channels and their mixing, a compartmental model was proposed and found to be fitting well to the RTD curve. Based on the results of the radiotracer study and model parameter, design modification of the glass production unit was undertaken to enhance its performance of the SGPU and improve quality of glass sheets.