Sustainability metrics of 1-butanol

Abstract

The production of chemicals from renewable resources often has to compete with a petrochemical process, optimized during several decades. Four sustainability metrics were used to compare the production of 1-butanol via the petrochemical and biobased processes: material efficiency, energy efficiency, land use and total costs. The selected petrochemical process is the oxo synthesis, i.e., the hydroformylation of propene, followed by the hydrogenation of the formed aldehydes with a yield of 95% 1-butanol. The selected biobased process is the anaerobic continuous acetone–butanol–ethanol (ABE) fermentation on glucose substrate from maize starch and a product recovery via distillation with a yield of 0.42gABEg−1 glucose. The petrochemical process has significantly higher material and energy efficiencies, compared to the biobased process. For the biobased process, land is used to produce the biomass (0.29haton−1), while no land is used for the petrochemical process. Production costs are higher for the biobased process (1041EURton−1), compared to the petrochemical process (915EURton−1). Based on the four metrics, the petrochemical process is preferable to the biobased process. However, biomass for sustainable fuels and chemicals will be the only resource for future generations. The efficiency of the biobutanol production can be improved by altering upstream processes, by metabolic engineering, by decreasing byproduct formation and by improving in situ product recovery techniques.