Species diagnostics and modeling study of laminar premixed flames fueled by acetone–butanol–ethanol (ABE)

Abstract

Acetone–butanol–ethanol fermentation processes are widely used for the bio-butanol production, while the preliminary product of this process is a ternary mixture of acetone, butanol and ethanol (ABE), the direct use of which without purification steps will substantially reduce the cost. In this study, in order to understand how the ketone–alcohol functionalities in ABE fuel affect the combustion intermediate species pool and the potential chemical cross-linking effects, the detailed chemical structures of laminar premixed flames fueled by ABE, an acetone–butanol (AB) mixture and an acetone–ethanol (AE) mixture were systematically investigated using molecular beam mass spectrometry with the synchrotron vacuum ultraviolet (SVUV) being the ionization source. About 40 species were unambiguously identified and quantified. A kinetic model was developed and validated against flames of individual fuels (acetone, ethanol and butanol), binary and ternary mixtures. The concentrations of benzene precursors, unsaturated hydrocarbons, and the toxic aldehydes were lower in the ABE flame than those in the butanol flame. Modeling analysis in respect of rate of production (ROP) indicated that these differences were attributed to the volume effects, instead of strong kinetic interactions among the reaction pathways of individual fuel components.