Chapter 22 - Macroscopic Approaches of Process Integration

Abstract

This chapter focuses on eco-industrial parks, material flow analysis, reverse problem formulation for watersheds, process integration as an enabling tool in environmental impact assessment, and process integration in life cycle analysis. The system boundaries can be drawn around a direct-recycle network, a mass-exchange network, a heat-exchange network, a cogeneration network, or the whole plant. Here, the boundaries are expanded to go beyond the plant and to include the surrounding environmental systems. The resources and wastes of multiple plants may be integrated in different ways and such “industrial symbiosis” opportunities call for the consideration of eco-industrial parks (EIPs). Several process integration techniques have been developed to synthesize cost-effective EIPs. A watershed covers a geographical region that includes one or more sources of water flowing through various surfaces and/or underground drainage pathways. Typically, a watershed involves a number of tributaries that feed into reaches, streams, or rivers and finally lead to a catchment area. Environmental impact assessment (EIA) is a procedure for evaluating and mitigating the biological, physical, chemical, economic, and social consequences of a proposed project on the surrounding environment. There are extensive process engineering activities involved in preparing an EIS. The activities include the generation of design alternatives, the techno-economic analysis, safety assessment, and the evaluation of the environmental consequences of each alternative. Finally, life cycle analysis (LCA) is an approach to the assessment of environmental impacts throughout the cradle-to-grace ecological cycle of a product, which involves extraction of the raw materials, processing, manufacturing, distribution, use, and discharge or recycle. Process integration results should be coupled with LCA to evaluate the environmental benefits beyond the process itself using a cradle-to-grave assessment.