Characterization and reactivity with NO/O2 of the soot formed in the pyrolysis of acetylene–ethanol mixtures

Characterization analyses and soot–O2 and soot–NO interaction experiments have been performed for soot samples obtained in the pyrolysis of acetylene–ethanol mixtures at different temperatures from 1275 to 1475 K. The objective of these analyses is to address the influence of soot formation conditions on soot properties and structure, as well as on its capability to interact with gaseous compounds.The characterization techniques used are: elemental analysis, transmission electron microscopy (TEM), Brunnauer–Emmett–Teller (BET) surface area analysis, Raman spectroscopy and X ray diffraction (XRD). The characterization of soot samples is useful to increase the database on soot composition and structure and may help to find a dependence of those characteristics with soot formation conditions and the fuel from which soot is formed. From these data it can be observed a certain degree of graphitization for the soot samples formed at higher temperatures and/or from fuel mixtures with a higher content in ethanol.The interaction of soot with NO and O2 is investigated in order to analyze the capability of soot to interact with gas reactants. Soot samples formed at the highest temperatures are less reactive towards O2 and NO than those formed at lower temperatures. Soot samples appear to be more reactive when the fuel mixture presents a lower initial volume of ethanol. These observations can be related to the higher C/H ratio, associated to slightly higher degree of ordering, for the soot samples formed in such conditions. Experimental results have also demonstrated that soot samples are more reactive towards O2 than NO, although the initial concentration of O2 is lower.

► Soot characterization and reactivity study. ► Dependence of soot characteristics and composition on formation conditions. ► Correspondence of soot characteristics and structure with its capability to interact with gas compounds.