Scheduling the cleaning actions for a fouled heat exchanger subject to ageing: MINLP formulation

• Published in: Computers & chemical engineering Vol. 39; pp. 179 - 185
• Main Authors: Pogiatzis, Thomas A., Wilson, D. Ian, Vassiliadis, Vassilios S.
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier Ltd 06.04.2012; Elsevier
• Subjects: Ageing; Applied sciences; Cleaning; Devices using thermal energy; Energy; Energy. Thermal use of fuels; Exact sciences and technology; Fouling; Heat exchangers; Heat exchangers (included heat transformers, condensers, cooling towers); Mathematical programming; MINLP; Operational research and scientific management; Operational research. Management science; Scheduling; Scheduling, sequencing; MINLP; Cleaning; Scheduling; Fouling; Heat exchangers; Ageing; Mixed integer programming; Non linear programming; Modeling; Case study; Heat exchanger; Non linear model; Timing
• ISSN: 0098-1354; 1873-4375
• DOI: 10.1016/j.compchemeng.2011.12.012

► The heat exchanger cleaning scheduling problem is revisited. ► Two cleaning methods are available with different cost and effectiveness. ► Ageing determines cleaning effectiveness. ► A new MINLP model is presented including these aspects. ► Results for a single heat exchanger show patterns called super-cycles. This paper addresses the problem of scheduling the cleaning actions of a heat exchanger undergoing fouling and ageing. The existence of two discrete layers leads to the use of two cleaning methods which differ in their ability to remove the aged layer. A mixed integer nonlinear programming (MINLP) model is presented and solved for three case studies with different ageing rates. The optimal schedule consists of: (i) the timing of the cleanings and (ii) the cleaning mode in each instant.