10th International Aerosol Conference September 2 - September 7, 2018 America's Center Convention Complex St. Louis, Missouri, USA
Abstract View
Structure and Size of Carbon nano-Particles Generated in Laminar Premixed Flames
MARIO COMMODO, Gianluigi De Falco, Patrizia Minutolo, Andrea D'Anna, IRC-CNR, Napoli, Italy
Abstract Number: 1470 Working Group: Combustion
Abstract The physicochemical properties of flame-generated carbon nanoparticles are investigated in a set of ethylene/air premixed flames with the objective of highlighting the peculiar characteristics of the particles produced across the transition from a mono-modal to a bi-modal particle size distribution.
Particle size distributions are measured by differential mobility analysis, while particle structure and composition are retrieved by Raman spectroscopy, UV–vis light absorption, X–ray and ultraviolet photoemission spectroscopy. Particle morphology is instead obtained by atomic force microscopy measurements.
Experimental results show that by increasing the flame residence time and equivalence ratio, particle size moves from a mono-modal, i.e., only nucleation-mode particles are formed, to bi-modal distribution when also an accumulation mode of particles is present. The change of the average particle size and the shape of the size distribution is associated to a strong change of the particle physicochemical properties. The combination of different analytical methods demonstrates that in richer flames the particles become more graphitic as the three-dimensional clustering of the aromatic planes proceed. Nevertheless, Raman spectroscopy shows evidence of a larger structural disorder in the accumulation mode particles as compared to the nucleation particles. This is most likely due to lattice distortion caused by the formation of five membered rings on the growing edges of the aromatic layers.