Comparison of thermal, rheological properties of Finnish Pinus sp. and Brazilian Eucalyptus sp. black liquors and their impact on recovery units.

Autor: Nuncira J; LUT University, Yliopistonkatu 34, 53850, Lappeenranta, Finland., Manoel GF; Pontifical Catholic University of Minas Gerais (PUC Minas), Belo Horizonte, MG, 30535-000, Brazil., Ribas Batalha LA; Federal Rural University of Rio de Janeiro (UFRRJ), Seropédica, RJ, 23890-000, Brazil., Gonçalves LM; Institute of Pure and Applied Sciences, Federal University of Itajubá (UNIFEI), Rua Irmã Ivone Drumond, 200 - Industrial District II, Itabira, MG, 35903-087, Brazil., Mendoza-Martinez C; LUT University, Yliopistonkatu 34, 53850, Lappeenranta, Finland. clara.mendoza.martinez@lut.fi., Cardoso M; Federal University of Minas Gerais (UFMG), Belo Horizonte, MG, 31270-901, Brazil., Vakkilainen EK; LUT University, Yliopistonkatu 34, 53850, Lappeenranta, Finland.
Jazyk: angličtina
Zdroj: Scientific reports [Sci Rep] 2024 Jul 05; Vol. 14 (1), pp. 15498. Date of Electronic Publication: 2024 Jul 05.
DOI: 10.1038/s41598-024-66513-z
Abstrakt: Black liquor (BL) is the major bioproduct and biomass fuel in pulp mill processes. However, the high viscosity of BL makes it a challenging material to work with, resulting in issues with evaporators and heat exchangers during its transport and processing. The thermal and rheological properties of BLs from Pinus sp. (PBL) and Eucalyptus sp. (EBL) were studied. FTIR spectra revealed the presence of the characteristic functional groups and the chemical composition in liquors. TGA/DTG curves showed three characteristic degradation stages related to evaporation of water, pyrolysis of organic groups, and condensation of char. Rheologically, liquors are classified as non-Newtonian and with comportment pseudoplastic. Their rheological dynamic shear properties included a linear viscoelastic region up to 1% shear strain, while frequency sweeps showed that storage modulus (G') > loss modulus (G''), thus confirming the solid-like behavior of both BLs. The rheological study demonstrated that increasing the temperature and oscillatory deformations of PBL and EBL decreased their degree of viscoelasticity, which could favor their pumping and handling within the pulp mill, as well as the droplet formation and swelling characteristics in the recovery furnace.
(© 2024. The Author(s).)
Databáze: MEDLINE
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