Eco-Efficiency Analysis For Chemical Process Design

Abstract

This paper addresses the problem of analyzing the various objectives involved in eco-efficient processes, meaning that ecological and economic considerations are taken into account simultaneously at the preliminary design phase of chemical processes. The environmental aspect is quantified at the preliminary design phase of chemical processes by using of a set of metrics or indicators following the guidelines of sustainability concepts proposed by IChemE [1]. The resulting multiobjective problem is solved by use of a genetic algorithm implemented in the so-called Multigen library. The trade-off between economic and environmental objectives is illustrated through Pareto curves. A key point of the methodology is the use of the package ARIANE™, a decision support tool dedicated to the management of plants utilities (steam, electricity, hot water…) and pollutants (CO 2 , SO 2 , NO x , etc..), used here both to compute the primary energy requirements of the process and to quantify its pollutant emissions. The well-known benchmark process for hydrodealkylation (HDA) of toluene to produce benzene, revisited here in a multi-objective mode, is used to illustrate the usefulness of the approach in finding environmentally friendly and cost-effective designs.