Global optimization for the synthesis of integrated water systems in chemical processes

https://www.ou.edu/class/che-design/pub-papers/A%20review%20of%20recent%20design%20procedures%20for%20water%20networks%20in%20refineries%20and%20process%20plants(Bagajewicz)-00.pdf

A review of recent design procedures for water networks in refineries and process plants

We propose a general superstructure and a model for the global optimization for integrated process water networks. The superstructure consists of multiple sources of water, water-using processes, wastewater treatment, and pre-treatment operations. Unique features are that all feasible interconnections are considered between them and multiple sources of water can be used. The proposed model is formulated as a nonlinear programing (NLP) and as a mixed integer nonlinear programing (MINLP) problem for the case when 0–1 variables are included for the cost of piping and to establish optimal trade-offs between cost and network complexity. To effectively solve the NLP and MINLP models to global optimality we propose tight bounds on the variables, which are expressed as general equations. We also incorporate the cut proposed by Karuppiah and Grossmann to significantly improve the strength of the lower bound for the global optimum. The proposed model is tested on several examples. © 2010 American Institute of Chemical Engineers AIChE J, 2011

Global superstructure optimization for the design of integrated process water networks

An automated method for the design of total water systems is developed in this paper. This approach considers simultaneously the optimal distribution of water to satisfy process demands and optimal treatment of effluent streams. Treatment can be for discharge to the environment or for regeneration of wastewater. The cases of regeneration reuse and regeneration recycle can be distinguished in the approach. It combines engineering insights with mathematical programming tools based on a superstructure model that results in a mixed-integer nonlinear programming problem. The approach features a fast and robust solution strategy. Complex tradeoffs involving operating, as well as capital, costs and other practical constraints have been included. In particular, piping and sewer costs, which are a major element in the capital cost of such systems, can be included. Network complexity is controlled by specifying the minimum permissible flow rates in the network, the maximum number of streams allowed at mixing juncti...

Automated design of total water systems

This paper addresses the optimum design of water utilization systems when a single contaminant is present. The application of the necessary conditions of optimality allows an LP or MILP formulation depending on the objective function of choice. Several examples are presented to illustrate the proposed methodology and to point out that several alternative solutions are available.

/pdf/on-the-use-of-linear-models-for-the-design-of-water-2s9s90fbqh.pdf

On the Use of Linear Models for the Design of Water Utilization Systems in Process Plants with a Single Contaminant

A mathematical programming model is proposed in this paper for determining the optimal water usage and treatment network (WUTN) in any chemical plant, which features the least amount of fresh water consumption and/or minimum wastewater treatment capacity. In particular, because design equations of all wastewater treatment facilities and all units which utilize either process or utility water are included in the model, more comprehensive integration on a plant-wide scale can be achieved. In comparison with the available technologies, the proposed method is more reliable, more accurate, and much faster in synthesizing the WUTNs. Furthermore, more cost-efficient alternatives may be identified in certain design cases.

http://www.che.ncku.edu.tw/FacultyWeb/ChangCT/html/publications/62%20A%20Mathematical%20Programming%20Model%20for%20Water%20Usage%20and%20Treatment%20Network%20Design.pdf

Han-Chern Ling

Papers

A Mathematical Programming Model for Water Usage and Treatment Network Design