GreenPro: a new methodology for cleaner and greener process design

Chemical and allied industries have shown interest in reducing pollution by implementing cleaner technologies or processes that use, or generate, lowe r amounts of or less harmful pollutants. However, abatement processes are s till required at many plants to reduce the discharge of pollutants at the e nd-of-the-pipe. It has been observed many times that efforts made to optimi se the abatement process reduce the quality and/or quantity of waste discha rge at the end-of-the-pipe, but increase the total environmental burden and impact. Therefore. it is very important to consider the environmental burd en and adverse impacts caused due to any change or modification in the proc ess and allied facilities for the complete system (up- and downstream of th e process). Moreover, these measures have generally been taken only after f ully fledged design of the process or at the operating stage, thus making t he preventive/abatement measure a costly affair. Therefore, there is great need for a design process (applicable to the early design and decision-maki ng stages) that not only considers economy and technology as the basic inpu t for the design, but also considers environmental soundness as one of the important parameters. This paper proposes a systematic methodology for process design that consid ers the assessment and minimisation of the environmental impacts of the com plete process system (including upstream processes), It incorporates life c ycle analysis (LCA) principles within a formal design process and optimisat ion framework. This proposed process design methodology with minimum enviro nmental impact extends to a complete description of the environmental impac t of the process and its associated activities. It has good real-life appli cation potential, as it includes environmental objectives together with tec hnology and economics at the design stage so as to determine a cost-efficie nt solution. Further, by employing process modelling and optimisation techn iques. it yields optimal design/operating conditions with minimum environme ntal impact. The applicability of the proposed methodology has been demonstrated through a real case study. The most interesting observation made in the case study is that the total cost of the optimised operation is minimum when the proc ess is designed and optimised considering the global boundary (the "cradle to the grave" approach) in contrast to the conventional boundary (process b oundary). (C) 2001 Elsevier Science Ltd. All rights reserved.