A Multiscale and Multiobjective Approach for Environmentally Conscious Process Retrofitting

Industrial society is increasingly recognizing the need for shifting to more sustainable activities. Business leaders have begun to realize that such changes are not only essential to prevent adverse social and environmental impacts, but also to assure the long term survival and success of their enterprises (Holliday, 1999). Sustainable practices can benefit a business directly by increasing its tangible financial value through costs and risk reduction, increasing efficiency and capital conservation; or by building up intangible value through reputation, strategic relationships, human capital, and innovation (Bakshi and Fiksel, 2003). This new direction in global thinking demands deep transformations in all organizations of society, including industrial, governmental and civil entities. Among the critical areas that need to change is Process Systems Engineering (PSE). There is a need for modifying the design and operation of existing processes and developing new products and technologies that minimizes environmental impact while still providing stimulating economic value to businesses. As part of these changes, other aspects of the process – such as resource consumption and environmental impact – must be included in the design process. In addition, since sustainability is a property of the entire system, design and assessment of industrial processes can no longer be studied in isolation, meaning that the system boundaries have to be expanded beyond the limits of the plant (Bakshi and Fiksel, 2003).