July 1-6, 2007
Optimising cleaning schedules for refinery preheat trains requires a robust and reliable simulator, reliable fouling models and the ability to handle the thermal and hydraulic impacts of fouling. The interaction between thermal and hydraulic effects is explored using engineering analyses and fouling rate laws based on the ‘threshold fouling’ concept; the potential occurrence of a new phenomenon, ‘thermo-hydraulic channeling’ in parallel heat exchangers, is identified. The importance of the foulant thermal conductivity is highlighted. We also report the development of a highly flexible preheat train simulator constructed in MATLAB/Excel. It is able to accommodate variable throughput, control valve operation and different cost scenarios. The simulator is demonstrated on a network of 14 heat exchangers, where the importance of optimising the flow split between parallel streams is illustrated.
E. M. Ishiyama, W. R. Paterson, and D. I. Wilson, "THE EFFECT OF FOULING ON HEAT TRANSFER, PRESSURE DROP AND THROUGHPUT IN REFINERY PREHEAT TRAINS: OPTIMISATION OF CLEANING SCHEDULES" 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/heatexchanger2007/9