CATEGORY: FOULING MONITORING
Proceedings of International Conference on Heat
Exchanger Fouling and Cleaning, June 9-14, 2013, Budapest, Hungary
Fouling
monitoring in thermosiphon reboiler
T. Kuwahara (1), C. Wibowo (2), A. Kuboyama (1), M. Nakamura (1),
and Y. Yamane (1)
1 Mitsubishi Chemical Corp., Okayama, Japan
2 Clear Water Bay Technology, Inc., Pomona, CA
Abstract
A
method to monitor the fouling resistance, Rf, of heat exchanger,
especially thermosiphon reboiler, is presented. The historical hourly data of
reboiler and distillation column are used to analyze Rf.
The initial value of overall heat transfer coefficient, U0,
and the current overall heat transfer coefficient, U, are needed to calculate
fouling resistance. Since U0 is not constant but is affected by
operating conditions such as shell/tube flow rate and temperature, a
relationship between U0 and these operating conditions has to be
developed to calculate Rf. However, sometimes important data such as
tube-side flow, inlet/outlet temperature of hot/cold fluid, liquid level in
shell/tube, that are needed to bring out the fouling condition of equipment,
are missing. With such insufficient information, the fuling behavior can be
analyzed by building a new equation based on measurable data. Dimensional
analysis determines the structure of the function; parameters of each term are
obtainable using short term plant data after cleaning, assuming that there is
no fouling during this period. As it is not easy to measure actual Rf
temporal change in the heat exchanger tube, the calculated fouling resistance
is compared with the relative amount of solid material removed from the
equipment during cleaning, and it is evaluated qualitatively. The comparison
shows good agreement. In addition, the evolution of the fouling resistance of
some thermosiphon reboilers over a period of a few months or even years can be
matched using this model.
Free Full Text Source: http://www.heatexchanger-fouling.com/papers/papers2013/65_Kuwahara_F.pdf
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