Sooting tendency of isopropanol-butanol-ethanol (IBE)/diesel surrogate blends in laminar diffusion flames

Recent advancements in metabolic engineering have demonstrated the cost-effective production of isopropanol-butanol-ethanol (IBE) from switchgrass biomass. As such, IBE is seen as a viable future fuel to transition the transportation sector towards renewable biofuels. In this study, an atmospheric co-flow diffusion flame burner was used to examine the sooting tendency of IBE when mixed with a diesel surrogate for blend ratios varying from 0% to 100% by volume. Experimental measurements of soot volume fraction were obtained by implementing a color-ratio pyrometry technique and reporting the variation of sooting tendency in terms of the Yield Sooting Index (YSI). Measurements demonstrated soot formation and hence YSI decreased nonlinearly with increasing IBE content. To gain further insight into the kinetics affecting soot formation, numerical modeling studies were carried out using laminarSMOKE ++ and a comprehensive kinetic mechanism with soot chemistry. From a reaction path and rate of production analysis, IBE demonstrated that it can perturb OH and HO 2 radical pools and enhance CO and CO 2 reactive channels from IBE oxygenated intermediates to suppress the formation of soot precursors. Studies were also extended to examine the role of CO 2 dilution on soot formation. It was shown that further soot reduction can be attained by lowering the rate of overall soot formation kinetics, perturbing reaction intermediates leading to soot formation by the depletion of H-atom radical pool, while enhancing the oxidation through enhanced OH-radical production. (c) 2023 The Combustion Institute. Published by Elsevier Inc. All rights reserved.

Automated summary

Recent advancements in metabolic engineering have shown that isopropanol-butanol-ethanol (IBE) can be produced cost-effectively from switchgrass biomass. This makes IBE a promising fuel for the future, allowing for a transition to renewable biofuels in the transportation sector. Experimental measurements and numerical modeling studies were conducted to examine the sooting tendency of IBE when blended with a diesel surrogate. The results showed that increasing the IBE content led to a decrease in soot formation and suggested potential mechanisms for reducing soot through the perturbation of reaction intermediates and the augmentation of oxidation reactions.