An MINLP model for biofouling control in seawater-cooled facilities

Abstract The use of seawater as a cooling agent in industrial plants is becoming a common practice in regions with water scarcity. One of the main problems of this approach is the heat transfer reduction due to biofouling in the heat exchangers. Biocide agents and scheduled maintenances are commonly used to control the biofilm growth. Dechlorination agents are also used to reduce the biocide concentration in the water discharge. In this work, a mathematical programming approach to develop optimal policies of biocide continuous dosing, dechlorination agents continuous dosing and maintenance scheduling for a seawater-cooled power desalination plant is presented. The resulting mixed integer nonlinear programming model can be used to test different dosing policies to detect a superior one. For the case study presented, results show that daily dosing policies offer an optimum economic policy, although biweekly and monthly dosing policies might provide a suitable compromise between economic and operating issues.

[1]  Sabah A. Abdul-Wahab,et al.  Levels of heavy metals in subtidal sediments in the vicinity of thermal power/desalination plants: a case study. , 2009 .

[2]  J. March,et al.  A kinetic model for chlorine consumption in grey water , 2005 .

[3]  Fen Huang,et al.  The density of seawater as a function of salinity (5 to 70 g kg 1 ) and temperature (273.15 to 363.15 K) , 2009 .

[4]  Frank J. Millero,et al.  Heat capacity of seawater solutions from 5° to 35°C and 0.5 to 22‰ chlorinity , 1973 .

[5]  Frank J. Millero,et al.  International one-atmosphere equation of state of seawater , 1981 .

[6]  James D. Bryers,et al.  Early fouling biofilm formation in a turbulent flow system: Overall kinetics , 1981 .

[7]  Ramasamy Venkatesan,et al.  Biofilm control for plate heat exchangers using surface seawater from the open ocean for the OTEC power plant , 2004 .

[8]  F. Millero,et al.  The density of seawater as a function of salinity (5 to 70 g kg ) and temperature (0 to 90 ° C) , 2009 .

[9]  R. P. Morgan,et al.  Destruction of phytoplankton in the cooling water supply of a steam electric station , 1969 .

[10]  A. K. Mohanty,et al.  Biofouling and its Control in Seawater Cooled Power Plant Cooling Water System - A Review , 2010 .

[11]  D. Sales,et al.  Model for fouling deposition on power plant steam condensers cooled with seawater: Effect of water velocity and tube material , 2007 .

[12]  Mahmoud M. El-Halwagi,et al.  Optimal scheduling of biocide dosing for seawater-cooled power and desalination plants , 2011 .

[13]  Ming-Hui Chen,et al.  A Model to Predict Total Chlorine Residue in the Cooling Seawater of a Power Plant Using Iodine Colorimetric Method , 2008, International journal of molecular sciences.

[14]  W. G. Characklis,et al.  Processes governing primary biofilm formation , 1982, Biotechnology and bioengineering.

[15]  Aldo R. Vecchietti,et al.  Modeling of discrete/continuous optimization problems: characterization and formulation of disjunctions and their relaxations , 2003, Comput. Chem. Eng..