Hemicelluloses Prior to Aspen Chemithermomechanical Pulping: Pre-Extraction, Separation, and Characterization

Abstract

A portion of hemicelluloses and acetic acid can be pre-extracted with dilute sulfuric acid prior to the aspen chemithermomechanical pulp process. The streams collected from the second press-impregnation stage after acid pre-extraction contain a significant amount of acid pre-extracted hemicelluloses. Most of the total sugars obtained from the pressate were xylan, in which xylan was further hydrolyzed to sugar monomers under the acid pre-extraction condition. To fully understand the characteristics of hemicelluloses yielded prior to pulping, the pre-extracted hemicelluloses were separated and characterized by FT-IR, (1)H NMR, and thermogravimetric analysis in this study. Most of the FT-IR bonds from the hemicelluloses agreed well with the other two spectra of birch xylan and CA0050 xylan, except a new absorption at 1734 cm(-1) contributed to acetyl groups. The hemicelluloses obtained from acid pre-extraction began to decompose significantly at about 225 °C, slightly lower in comparison with organosolv and alkaline hemicelluloses reported in the literature.

Chemithermomechanical and kraft pulping of Pinus radiata wood chips after the hydrothermal extraction of hemicelluloses

“…The removal of lignin and hemicelluloses could be responsible for the energy reduction for refining, resulting in more loose, collapsible, and easier separable fibers. A similar behavior was observed by Liu et al (2012) in the CTMPs after the HT of Populus tremuloides Michx.…”

“…The tear index was slightly higher in the pulps from HT chips. Liu et al (2012) found that the HT P. tremuloides pulps have a similar tear index than the untreated control pulps. According to Spiegelberg (1966), the removal of hemicelluloses decrease the strength properties of the fibers by the inhibition of the internal stress distribution, replacing the flexible hemicellulose-cellulose bond by a more rigid cellulose-cellulose bond.…”

Generation of New Cationic Xylan-Based Polymer in Industrially Relevant Process

“…2,3 Hemicellulose can be extracted from biomass via hydrolysis prior to pulping or cellulosic ethanol production. 4 Steam or hot water hydrolysis is commercially used in pulp production from hardwood species. 1,5 It is therefore understood that hemicellulose can be available at a large quantity for use.…”

Saccharide separation from wood prehydrolysis liquor: comparison of selectivity toward non-saccharide compounds with separate techniques

“…Therefore, prehydrolysis liquor (PHL) is identied as a potential feedstock for OS production and receives great attention due to its contribution to the industrial biorenery. [5][6][7][8] However, PHL also contains various non-saccharide compounds (NSC) that are released during the prehydrolysis step. NSC includes wood resins, water soluble aromatic compounds from lignin depolymerization, 9,10 organic acids and furans from carbohydrate degradation.…”