Distributed combustion of diesel–butanol fuel blends in a mixture temperature-controlled burner

Abstract

Butanol is a promising candidate to increase the share of renewable fuels in our liquid fuel portfolio for industry and transportation. The combustion of four B0-B50 diesel fuel-n-butanol blends was investigated in a Mixture Temperature-Controlled burner, a novel archetype of turbulent swirl burners for ultra-low emissions to provide data on the effect of butanol blending for steady-operating applications. Stable combustion of blended fuels was limited to an equivalence ratio of 0.76 in our burner, which is a notable drawback compared to that of diesel fuel in this test system. Distributed flames feature low luminosity and single-digit CO and NOX emissions in ppm at 15% O2 level, the representative for gas turbines, fulfilling all the current NOX regulations with 86% margin on average. The CO emission was inferior in all cases. The chemiluminescent intensity of OH* was sufficient for evaluation at all flames except for distributed combustion, which is the favorable flame type. The acoustic spectrum of various fuels under identical conditions was highly similar, concluding easy interchangeability from a combustion acoustics point of view. Moreover, the noise of distributed combustion was 10 dB lower than that of straight flames for all fuels and conditions.