Optimization of scale formation rate in heat exchangers using thermohydraulic theory

Document Type : Chemistry Article

Author

Chemical & Petroleum Engineering Department, Sharif University of Technology, Tehran, Iran

Abstract

In this research, utilizing the concepts of thermohydraulic theory, optimization of cost due to the scale formation in heat exchangers. The objective function involves the minimization of the energy consumption and production losses. First, via ASPEN we simulated shortcuts of exchangers in order to examine the effects of temperature and velocity on the scale formation. The project optimization was done by GAMS and due to the presence of nonlinear terms in the scale rate equations using CONOPT solver. For better results, Heat Exchanger 4131 and 4132 in Khorasan petrochemical Co. urea unit were used.

The investigation shows that for the twin exchangers under study, first, the scale formation reduces cooling water flow by up to 40% in E4132. Second, the optimal values for minimizing cost of scale formation in the exchangers occurs at a cooling water flow rate of 152442.75 kg/h for the exchanger 4132 to reduce the cost by 15%.

Keywords

Main Subjects


[1] Ibrahim, H.A.’’MATLAB—A Fundamental Tool for Scientific Computing and Engineering Applications’’. In Fouling in Heat Exchangers. London, UK. Volume 3.  August 2012. pp. 57–96.
[2] Richards, C.S., F. Wang, W.C. Becker, and M.A. Edwards, ‘’A 21st-Century Perspective on Calcium Carbonate Formation in Potable Water Systems’’. Environmental Engineering Science. 2018 pp.143-158.
[3] Ishiyama, E. M., & Pugh, S. J., ‘’Effect of flow distribution in parallel heat exchanger networks: use of thermo-hydraulic channeling model in refinery operation’’. Heat Transfer Engineering. 2018. pp 1–27.
[4] Kern, D. Q., and Seaton, R. A., ‘’A Theoretical Analysis of Thermal Surface Fouling’’. British Chemical   Engineering. vol. 4. February 1955. pp. 258–262.
[5] N. Epstein. Fouling in Heat Exchangers. 3rd ed. McGraw-Hill. New York 1983.
[6] Smaïli, F., Vassiliadis, V. S., & Wilson, D. I. ‘’Mitigation of Fouling in Refinery Heat Exchanger Networks by Optimal Management of Cleaning’’. Energy & Fuels.  January 2001. pp. 1038–1056.
[7] Yeap, B.L., Wilson, D.I., Polley, G.T., Pugh, S.J., ‘’Mitigation of crude oil refinery heat exchanger fouling through retrofits based on thermo-hydraulic fouling models’’. Chemical Engineering Research and Design. August 2004. pp. 53-71.
[8] Patrick Walker. ‘’ CFD modelling of Heat Exchanger Fouling’’. A Thesis submitted for the degree of Doctor of Philosophy. Sydney Australia. 2005.
[9] H. Köhler, H. Stoye, M. Mauermann, and J. -P. Majschak. ‘’ Optimization approach for efficient cleaning with impinging jets – influence of nozzle diameter, pressure and nozzle distance’’.Heat Exchanger Fouling and Cleaning, Budapest. Hungary. 2013. pp. 106-118.
[10] Diaz-Bejarano, E., Coletti, F., & Macchietto, S. ‘’Modeling and Prediction of Shell-Side Fouling in Shell-and-Tube Heat Exchangers’’. Heat Transfer Engineering. 2018. pp. 1–17.
[12] Ramesh K. Shah Dušan P. Sekulić. Fundamentals of Heat Exchanger Design. John Wiley & Sons. 2003.
[13] Ishiyama, E. M., Paterson, W. R., & Wilson, D. I., ‘’Thermo-hydraulic channeling in parallel heat exchangers subject to fouling’’. Chemical Engineering Science. August 2008. pp. 3400–3410.
[14] Eric C. Carlson, ‘’ Don’t Gamble with Physical Properties for Simulations’’. Aspen Technology. 1998.
[15] Ćalasan, M. P., Nikitović, L., & Mujović. ‘’ CONOPT solver embedded in GAMS for optimal power flow’’. Journal of Renewable and Sustainable Energy. December. 2019. pp.  46-67.
]16[ کامیار کمانی و روح الله رفعی، "بررسی انتقال حرارت و جریان آرام نانوسیال از دیدگاه قانون دوم ترمودینامیک در یک مبدل حرارتی جریان مخالف"، نشریه مدل‌سازی در مهندسی، دوره 13، شماره 41، تابستان 1394، صفحه 57- 47.
]17[ محمدرضا حسن‌زاده و فرشید کی‌نیا، "ارائه یک مدل جدید برای جستجوی ترکیبی هوشمند جهت پیدا نمودن پاسخ بهینه سراسری مسایل مهندسی"، نشریه مدل‌سازی در مهندسی، دوره 17، شماره 58، پاییز 1398، صفحه 102-81.