Flow Blurring Atomization for Low-Emission Combustion of Liquid Biofuels

Abstract

In this study, clean combustion of straight vegetable oil (VO) is achieved by utilizing a novel flow blurring (FB) fuel injector with superior atomization characteristics. Experiments are conducted in an atmospheric pressure combustor using three different fuels: straight VO, which is fully-refined soybean oil, biodiesel produced from soybean VO, and No. 2 diesel. Combustion performance is assessed by comparing flame images, emissions profiles at the combustor exit plane, and pressure drop in fuel and atomizing air lines. Results show that the FB atomizer can create clean burning spray flames of straight VO without preprocessing and/or preheating. The FB injector produces sprays with smaller diameter fuel droplets to promote combustion in the premixed mode. All fuels resulted in similar CO emissions, while biodiesel flames had the lowest NO_X emissions. Pressure drop in the fuel and atomizing air lines was independent of the fuel.

Keywords:

• Biodiesel
• Fuel atomization
• Liquid biofuels
• Vegetable oil

ACKNOWLEDGMENTS

This research was supported in part by the U.S. Department of Energy through grant EE0001733. B. S. was supported by the Graduate Assistance in Areas of National Need (GAANN) Fellowship program of the U.S. Department of Education.