Resumo

BALOYI, Hope  e  DUGMORE, Gary. Pyrolytic topping of coal-algae composite under mild inert conditions. J. energy South. Afr. [online]. 2019, vol.30, n.3, pp.44-51. ISSN 2413-3051.  http://dx.doi.org/10.17159/2413-3051/2019/v30i3a5763.

Co-processing of coal and biomass has been a focus of several research studies aimed at addressing the negative environmental attributes associated with thermal processing of coal alone, as well as improving the thermal behaviour of coal. Biomass materials are regarded as a clean, renewable source, so thermal coprocessing of biomass with coal is considered an effective way to utilise coal in a sustainable manner. In this study, coal fines were blended with Scenedesmus microalgae slurry to form a coal-algae composite. Pyrolytic topping of coal-algae composite was performed at 450 °C on a batch reactor. Parent fuels and resultant chars were analysed for their proximate properties using an Eltra thermostep TGA; a Vario EL cube Elementar was used to determine the elemental composition of the chars and oils. A simulated distillation (SimDis) method was used to determine the boiling point distribution of the produced oils. The objective of the study was to examine the effects of microalgae slurry on the pyrolytic behaviour of waste coal fines with respect to product yields, composition and quality. Results showed that the yields of volatile components from pyrolysis of coal-algae composite were high compared with those from pyrolysis of coal alone. A significant degree of deoxy-genation, dehydrogenation and denitrification was observed in coal-algae char than coal char. SimDis results showed that the fossil bio-crude oil has different boiling point characteristics from coal tar. The study has shown that microalgae slurry has potential to influence the pyrolytic behaviour of waste coal under mild inert conditions. Highlights • Pyrolysis of the fuel composite results in low yields of char. • Coal-algae composite pyrolysis results in a substantial degree of dehydrogenation. • Fossil bio-crude oil contains more reactive compounds than coal tar. • Coal-algae chars contains lower contents of sulphur and nitrogen than coal, which is desirable to reduce emissions of sulphur and nitrogen oxides during the combustion process • Fossil bio-crude oil have compounds that are predominantly in the distillate fuel oil range

Palavras-chave : fossil bio-crude oil; resultant char; mild pyrolysis; coal-algae composite.

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