Life cycle assessment as a tool for evaluating chemical processes at industrial scale: a review

Abstract

The present paper reviews 47 Life Cycle Assessments (LCA) applied to chemical reactions. The selection of the evaluated articles was conducted with a systematic literature review methodology. The review arises from the need to define the best methods for developing LCAs of chemical processes at industrial scale. The authors go through the stages defined in ISO 14040 and 14044, identifying both the gaps and the best techniques used in all the reviewed papers. The main difficulty observed when developing LCAs of chemical reactions is the lack of data due to confidentiality issues in chemical companies. In addition, this data is commonly only available at the laboratory scale. Laboratory data is sometimes directly upscaled without further consideration. Even though, simulation software, advanced calculations benchmarks, pinch analysis and retrosynthetic analysis are the best methods to estimate and scale up the mass and energy balances in the Life Cycle Inventory (LCI) stage. The article discusses these upscale procedures, makes a deep analysis of each single LCA stage, and assesses how chemical process information is managed, which is a novelty regarding previous reviews of chemical reaction LCA. From the Life Cycle Impact Assessment (LCIA) methodologies, they should be standardized to enable the comparability between LCAs of the same product. Both the European Commission and the Life Cycle Initiative are making progress in this regard. Eventually, the ReCiPe is the most used methodology among the reviewed papers. Finally, the article proposes different analyses to be performed in the interpretation phase: i.e., projecting the energy mix foreseen for the years 2030 and 2050 in energy-intensive processes or including other sustainability vectors (economic and social) in cross-cutting projects.