RESIDENCE TIME DISTRIBUTION OF LIQUIDS IN A CONTINUOUS TUBULAR THERMAL-PROCESSING SYSTEM - PART I - RELATING RTD TO PROCESSING CONDITIONS

A systematic experimental study on residence time distribution (RTD) i n tubular flow was performed, covering a wide range of processing cond itions. The flow of water in various sections of a tubular continuous thermal processing system was analysed using the classical Danckwerts approach. Methylene blue was used as tracer and different constant tem peratures (25-80 degrees C) and flow, rates (80-380 ii h) were rested These conditions yielded mean residence times up to 6 min and Reynolds numbers between 1350 and 9700 Various models were fitted to the exper imental darn, and the dispersion model showed to yield the best fit. P eak analysis led to both accurate and precise as well as conservative parameters, when compared to other methods of parameter estimation. Re sults revealed that fluid dispersion in tubular flow (Peclet number) c an be related to processing conditions (Reynolds number) by a power la w model Results were compared to published correlations. (C) 1998 Else vier Science Limited. All rights reserved.