Full Length Article Separation and characterization of carbonaceous particulate (soot and char) produced from fast pyrolysis of coal in inert and CO 2 atmospheres B. Apicella a,⇑ , O. Senneca a , C. Russo a , S. Heuer b , L. Cortese a , F. Cerciello c , V. Scherer b , M. Schiemann b , A. Ciajolo a a Istituto di Ricerche sulla Combustione, IRC-CNR, P.le Tecchio 80, 80125 Napoli, Italy b Department of Energy Plant Technology, Ruhr-Universität Bochum, Universitätsstr. 150, 44780 Bochum, Germany c DICMAPI, University Federico II, P.le Tecchio 80, 80125 Napoli, Italy highlights  Effect of inert and CO 2 -rich atmospheres on the fast pyrolysis of coal.  Separation method of soot and char from carbon particulate formed in coal pyrolysis.  Structural characterization of coal- derived soot and char.  Soot and char formation mechanisms. graphical abstract article info Article history: Received 30 May 2016 Received in revised form 27 October 2016 Accepted 15 November 2016 Available online xxxx Keywords: Soot Char Coal Fast pyrolysis Drop tube abstract In a previous work [Heuer et al., 2016] a large production of a fluffy carbon-rich material was observed to accompany the char formed during the early stages of a medium rank (bituminous) coal pyrolysis in a drop tube furnace (1573 K, residence times < 130 ms). This peculiar material was found to be much more abundantly formed in CO 2 than in N 2 flow. SEM analysis showed that it contains a large portion of sub- micron soot-like particles mixed with particles of tenths of microns in size with the typical char morphol- ogy. The present work reports on the separation of the two differently sized fractions produced in CO 2 and N 2 flow and their subsequent analysis. The separation was performed dispersing the material in etha- nol by ultrasonic mixing, followed by settling, and decanting to produce top and bottom products enriched in the fine and coarse particle fractions, respectively. The procedure was repeated several times and the size separation effectiveness was checked by SEM and laser granulometry sizing. Thermogravimetry, elemental and spectroscopic analysis were applied to the coarse and fine fractions to provide insights on their structural features. The fine soot particulate was almost ash-free, suggesting that its formation occurs in the gas phase, as typically soot does, while the coarse fraction presented sig- nificant residues of coal inorganic matter typical of char. Both fine and coarse particulate resulted less reactive, and somewhat smaller in size, when produced in CO 2 in comparison to N 2 /Ar pyrolysis conditions. Their lower reactivity is associated with higher aro- maticity and structural order as well as with a lower presence of hydrogen and aliphatic functionalities. Ó 2016 Elsevier Ltd. All rights reserved. http://dx.doi.org/10.1016/j.fuel.2016.11.049 0016-2361/Ó 2016 Elsevier Ltd. All rights reserved. ⇑ Corresponding author. E-mail address: apicella@irc.cnr.it (B. Apicella). Fuel xxx (2016) xxx–xxx Contents lists available at ScienceDirect Fuel journal homepage: www.elsevier.com/locate/fuel Please cite this article in press as: Apicella B et al. Separation and characterization of carbonaceous particulate (soot and char) produced from fast pyrolysis of coal in inert and CO 2 atmospheres. Fuel (2016), http://dx.doi.org/10.1016/j.fuel.2016.11.049