Radioactive tracer investigation of the flow characteristics in a continuous vacuum PAN in sugar industry

A residence time distribution study was carried out in a continuous vacuum pan (crystallizer) in a sugar industry using radiotracer technique. The objectives of the study were to measure mean residence time of massecuites and to investigate flow pattern in pan. 24Na as sodium chloride and 82Br as ammonium bromide were used as tracers. The tracer was injected as a delta input into the grain feed pipe of the pan and monitored at the outlet of each compartment using collimated scintillation detectors connected to a data acquisition system. The monitored output tracer curves were analysed to obtain mean residence time and flow behaviour of the pan. Axial dispersion model was used to simulate the tracer output curves. The results indicated that the pan did not behave as a plug flow system as desired. (author)