Skip to main content

Research Repository

Advanced Search

Evaluation of hydrochars from lignin hydrous pyrolysis to produce biocokes after carbonization

Castro-D�az, M.; Uguna, Clement N.; Florentino, L.; D�az-Faes, E.; Stevens, L.A.; Barriocanal, C.; Snape, C.E.

Evaluation of hydrochars from lignin hydrous pyrolysis to produce biocokes after carbonization Thumbnail


Authors

M. Castro-D�az

L. Florentino

E. D�az-Faes

LEE STEVENS LEE.STEVENS@NOTTINGHAM.AC.UK
Senior Research Fellow

C. Barriocanal

COLIN SNAPE COLIN.SNAPE@NOTTINGHAM.AC.UK
Professor of Chemical Technology & Chemical Eng



Abstract

Hydrochars were obtained after hydrous pyrolysis of a pine Kraft lignin using different reaction conditions (temperature, water content and residence time) and the residues were characterized through a wide range of analytical techniques including high-temperature rheometry, solid-state 13C nuclear magnetic resonance (NMR), thermal gravimetric analysis (TGA), diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) and field emission scanning electron microscopy (FE-SEM). The results indicated that an increase in reaction temperature, an increase in residence time or a decrease in water content reduces the amount of fluid material in the residue. The hydrous pyrolysis conditions studied were not able to increase the maturation of lignin, which would result in an increase in the resolidification temperature, but reduced the amount of mineral matter in the hydrochar produced. On the other hand, the hydrochars obtained from pristine lignin, torrefied lignin (300 °C, 1 h) and their 50:50 wt.%/wt.% blend at temperatures of 350 °C after 6 h using 30 ml of water had lower ash contents (<2 wt.%) than the parent lignin (2.5 wt.%) and a high rank good coking coal (10 wt.%). However, the reactivity of the resulting biocokes (>45%) is excessively high compared to that of the good coking coal (10%) and the micro-strength of the biocokes (R1<1%) is much lower than that of the coal (R1 = 17%). These findings could be rationalized by the high total porosity (>39%) and high microporous surface areas ( > 400 m2/g) of the biocokes and high alkalinity index of the lignins (>27%) compared to those of the coke (27% and 145 m2/g) and coal (0.6%), respectively. Furthermore, the biocoke derived from the hydrous pyrolysed torrefied lignin did not agglomerate, which could not be explained by changes in the chemical properties of the material and requires further investigation.

Citation

Castro-Díaz, M., Uguna, C. N., Florentino, L., Díaz-Faes, E., Stevens, L., Barriocanal, C., & Snape, C. (2017). Evaluation of hydrochars from lignin hydrous pyrolysis to produce biocokes after carbonization. Journal of Analytical and Applied Pyrolysis, 124, 742-751. https://doi.org/10.1016/j.jaap.2016.11.010

Journal Article Type Article
Acceptance Date Nov 18, 2016
Online Publication Date Nov 19, 2016
Publication Date Mar 30, 2017
Deposit Date Jan 26, 2017
Publicly Available Date Nov 20, 2017
Journal Journal of Analytical and Applied Pyrolysis
Print ISSN 0165-2370
Electronic ISSN 1873-250X
Publisher Elsevier
Peer Reviewed Peer Reviewed
Volume 124
Pages 742-751
DOI https://doi.org/10.1016/j.jaap.2016.11.010
Keywords Lignin; Torrefaction; Hydrous pyrolysis; Biocoke; Carbonization
Public URL https://nottingham-repository.worktribe.com/output/827880
Publisher URL https://www.sciencedirect.com/science/article/pii/S0165237016305897
Contract Date Jan 26, 2017

Files





You might also like



Downloadable Citations