July 1-6, 2007
Maya crude oil fouling reveals a seemingly straightforward dependency of initial fouling rate on surface temperature but a maximum is found in the initial fouling rate – velocity relationship which mirrors that found in a model chemical system of styrene polymerization. The linear dependency of the logarithm of the pre-exponential factor on apparent activation energy for the crude oil is also found in the styrene system. The apparent activation energy for the crude oil ranged from 26.4 kJ/mol at 1.0 m/s to 245 kJ/mol at 4.0 m/s. Such strong dependencies of apparent activation energy on velocity, even at high velocity, are consistent with Epstein’s mass transfer-reaction-attachment model. Surface temperatures at which the fouling rate becomes velocity-independent are 274°C and 77°C for Maya crude oil and styrene, respectively. For surface temperatures in excess of this isokinetic temperature, an increase in velocity would lead to an increase in the rate of fouling.
B. D. Crittenden, S. T. Kolaczkowski, T. Takemoto, and D. Z. Phillips, "CRUDE OIL FOULING IN A PILOT-SCALE PARALLEL TUBE APPARATUS" in "Heat Exchanger Fouling and Cleaning VII", Hans Müller-Steinhagen, Institute of Technical Thermodynamics, German Aerospace Centre (DLR) and Institute for Thermodynamics and Thermal Engineering, University of Stuttgart, Germany; M. Reza Malayeri, University of Stuttgart, Germany; A. Paul Watkinson, The University of British Columbia, Canada Eds, ECI Symposium Series, (2007). http://dc.engconfintl.org/heatexchanger2007/5