ABSTRACT
Water is an essential resource widely used in the process industries as a raw material, a heat-transfer medium, or a mass separating agent. Common uses in the latter case include steam stripping, liquid-liquid extraction, and various washing operations. Rapid industrial growth has increased fresh water consumption as well as wastewater production, and consequently caused serious water pollution in the world. Concurrently, the scarcity of industrial water (partly due to climate change) and increasingly stringent discharge regulations have led to rising costs of fresh water and effluent treatment. These environmental and economic issues stimulated the recent development of systematic methodologies for efficient and responsible use of water in industry. Particularly, design of water recovery systems through process integration techniques, also known as water network synthesis, has been commonly accepted as an effective means in this regard, with reuse, recycling, and
13.1 Introduction .................................................................................................. 319 13.2 Problem Statement ........................................................................................ 320 13.3 Integration of Continuous and Batch Units .................................................. 320 13.4 Mathematical Formulation ........................................................................... 321
13.4.1 Time Representation for Cyclic Operation ....................................... 322 13.4.2 Mass Balance for Truly Batch Units ................................................. 322 13.4.3 Mass Balance for Semicontinuous Units .......................................... 324 13.4.4 Mass Balance for Storage Tanks ......................................................324 13.4.5 Objective Functions .......................................................................... 327
13.5 Illustrative Examples .................................................................................... 328 13.6 Summary ...................................................................................................... 332 Nomenclature ......................................................................................................... 333 References .............................................................................................................. 334
regeneration as possible options for reducing fresh water and wastewater (Wang and Smith 1994).
