One of the premier challenges facing chemical industry is transitioning to more sustainable operations. Increasingly tightening regulatory regimes at local, state, national and international levels, increased consumer awareness, and inclination of investors to consider risks associated with lendings to hazardous material industries are some of the factors motivating such transition. Industries are taking initiatives to improve their triple bottom-line by reducing resource intensities or footprints, and by adopting intrinsically safer materials and processes. Such efforts need to be supported by techniques that can quantify the broad economic and environmental implications of industrial operations, retrofit options and new design alternatives.

Life Cycle Assessment is one of most popular techniques that provide such cradle-to-grave analysis by considering various stages of supply, production and demand networks. LCA mainly focuses on emissions and their impact, and considers consumption of some non-renewable resources and land use. Other techniques such as Material Flow Analysis, Full Fuel Cycle Analysis, Exergetic LCA, and Industrial Cumulative Exergy Consumption Analysis have also been proposed and used in various circles to different extents. However, their wide-spread use has been hindered by number of shortcomings including lack of compliance with basic biophysical laws and inability to consider diverse array of ecological resources.

The recently developed Ecologically-Based Life Cycle Assessment (Eco-LCA) represents a major advance over other contemporary techniques by addressing many of their shortcomings [1]. It is rigorous as it ensures compliance with basic biophysical laws such as the first and second laws of thermodynamics. It is also environmentally conscious as it analyzes economic, environmental and social systems as integrated networks of material and energy flows with exergy as the common currency. Eco-LCA is an extension of previously developed Thermodynamic Input-Output LCA to include many more resource categories [2].

This presentation will apply Eco-LCA model of the U.S. economy to analyze resource intensities of chemical industry sectors, comparing them with each other and with other industry sectors. Raw industry-specific numbers for resource consumption and emissions will be presented in mass and exergy units, and with and without considering the contribution of ecological resources. In addition, industry-specific numbers will be normalized by national flows to gain insight into possible resource vulnerabilities of industry sectors. These numbers will also be aggregated based on mass or exergy to reduce dimensionality and permit easier interpretation. Insights obtained from such analysis can be used to identify opportunities to reduce resources intensities, and improve environmental sustainability of chemical industry.

References:

[1] Zhang, Y.; Baral, A.; Bakshi, B. R., 2007. “Ecologically Based Life Cycle Assessment”, AIChE Annual Conference, paper 650a, San Francisco, CA.

[2] Ukidwe, N. U.; Bakshi, B. R., 2007. “Industrial and Ecological Cumulative Exergy Consumption of the United States via the 1997 Input-Output Benchmark Mode”, Energy, 32, 9, 1560-1592.