Effects of pyrolysis conditions on the structure of chars prepared from an Argentine asphaltite

NASSINI D.; FOUGA G. G.; NASSINI H.; BOHÉ A. E.

FUEL

ELSEVIER SCI LTD

Lugar: Amsterdam; Año: 2016 vol. 182 p. 623 - 631

0016-2361

As gasification reactivity of carbonaceous solidmaterial chars is known to be strongly dependent on their formation conditions,a comprehensive study was carried out on the effects of pyrolysis conditions onstructure of chars prepared from an Argentine asphaltite. The study comprisedqualitative and quantitative analyses of char structures by X-ray diffraction, complementedwith the characterization of physical morphology of char particles by scanningelectronic microscopy and high-resolution transmission electronic microscopy.Effects of pyrolysis temperature, heating rate and holding time at the peaktemperature were investigated separately in a fixed bed tubular reactor.Additionally, the overall effect of variations in time-temperature history ofindividual char particles was evaluated using a drop tube furnace reactor.Experimental results have shown that pyrolysis conditions have a stronginfluence on the asphaltite-derived char structure, producing a significantreordering of the carbonaceous matrix at high heat treatment temperatures thatis evidenced by increments in aromaticity and crystalline carbon fraction. Theresulting physical morphology of asphaltite-derived char particles was found tobe profoundly influenced by the heating rate at which the volatile matter isreleased, due to the appearance of a liquid phase during the heating process.