Using life cycle assessment to guide catalysis research

Document Type

Article

Publication Date

7-15-2009

Abstract

The use of life cycle assessment (LCA) as a tool to guide catalyst development is demonstrated by comparing the environmental impact of acrylic acid production from propylene, the current commercial feedstock, to propane as an alternate feedstock. Acrylic acid is currently produced in a two-step process from propylene. Because of its lower cost, propane is an attractive alternative to propylene; however, no catalysts are currently available that can compete with the high yield of the propylene process. The LCA was performed using SimaPro, and impact assessment was determined using the Eco-Indicator 99 method. A comparison of the two feedstocks at the 87% yield of the current commercial propylene process demonstrated that switching to propane would decrease the environmental impact of the process by 20%. Determination of environmental impact as the yield from the potential propane process was varied predicts that, at yields exceeding 6%, the propane process will have a lower environmental impact than the current propylene process. By focusing on particular categories such as fossil fuels or climate change, the propane process will have a lower impact for yields exceeding 15 and 33%, respectively. The current catalyst yield of up to 48% for the propane process exceeds these values. If reaction and waste gas heat are converted to electricity instead of steam, yields in excess of 61% will result in a lower total impact for the propane process. On the basis of raw material costs, the economic break-even point for the propane process is 59% yield. The similar yields of ~60% from propane required by economics and for a lower environmental impact represents a factor of 1.25 increase in yield over the current state-of-the-art propane catalyst compared to a factor of 1.81 increase in yield required to equal the current propylene yield. Thus, the proposed propane process may be much closer to viability than previously realized. This analysis provides an example of how LCA can compare chemical production from two different feedstocks, even if a catalyst for the reaction of interest has not been designed. The LCA analysis can also be used to determine target goals for catalysis research. © 2009 American Chemical Society.

Publication Title

Industrial and Engineering Chemistry Research

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