LIFE-CYCLE ASSESSMENT APPLIED TO PROCESS DESIGN - ENVIRONMENTAL AND ECONOMIC-ANALYSIS AND OPTIMIZATION OF A NITRIC-ACID PLANT

Life Cycle Assessment (LCA) is an environmental auditing tool that qua ntifies the environmental burdens of an activity inclusive of all its related systems. In the past, LCA has been applied primarily to produc ts, but recent literature suggests it also has potential as an analysi s and design tool for processes and services. This potential arises fr om the unique ability of LCA to link the environmental burdens of a pr ocess with its mass and energy flows. The aim of this work is to apply LCA as a tool for process design rather than one for product assessme nt. A nitric acid plant formed the basis for a case study wherein LCA was used to quantify and compare environmental performance of a number of design alternatives aimed at waste reduction. Economic models for the alternatives were formulated and linked to the environmental model s to perform a multiobjective optimization with the express aim to max imize economic returns and minimize environmental impact. The comparat ive study showed that one design alternative teas clearly superior fro m an environmental point of view. The optimization demonstrated that o perational changes could result in significant environmental improveme nt at minimal economic cost. Future work in this area should focus on the allocation of environmental burdens from multiple-output processes as well as extending the analysis to include environmental and econom ic impacts of all related downstream processes.