(423e) Planning Model of Water Networks

Although many methodologies dealing with optimization of water systems have been proposed (see Bagajewicz, 2000 for works up to 2000; Savelski and Bagajewicz, 2001; Koppol and Bagajewicz, 2003; Gunaratnam et al., 2005; Karuppiah and Grossmann, 2006; Alva-Argaez et al., 2007; among others), none of them consider future demands.

In this paper we propose a planning model that is concerned with future expansions and/or environmental regulations, which can be stated as follow: Given a water system with different situations in time, it is desired to determine where, when and what capacity of connections are needed; which, when and what capacity of treatment processes (if any) need to be installed to obtain an optimum network for any given time. We present this as a capacity expansion problem.

The planning model is based on the conventional WAP model, but it includes the time dimension. For different points in time, one may have different instances of an increase in mass loads, a planned addition of water-using units in the future, a future reduction of discharge limits, etc. We will compare the use of a planning model with two alternatives: a) Solving for the current needs and then solving a retrofit problem for the next point in time. b) Solving the problem considering the worst case scenario. i.e. the highest loads.

Alva-Argaéz, A., Kokossis, A.C., Smith, R. (2007). A conceptual decomposition of MINLP models for the design of water-using systems. Int. J. Environment and Pollution. 29, 177.

Bagajewicz, M. (2000). A review of recent design procedures for water networks in refineries and process plants. Computers and Chemical Engineering, 24, 2093-2113.

Gunaratnam, M.S. (2003). Total water system design. Ph.D. Thesis, University of Manchester Institute of Science and Technology - UK.

Karuppiah, R., Grossmann, I.E. (2006). Global optimization for the synthesis of integrated water systems in chemical processes. Computers and Chemical Engineering, 30, 650-673.

Koppol, A.P.R., Bagajewicz, M.J., Dericks, B.J. and Savelski, M.J. (2003). On zero water discharge solutions in the process industry. Advances in Environmental Research, 8, 151?171.

Savelski, M. J. and Bagajewicz, M. J. (2001). Algorithmic Procedure to Design Single Component Water Utilization Systems in Process Plants. Chemical Engineering Science, 56, 1897-1912.