Pre-extraction of hemicelluloses and subsequent kraft pulping Part II: Acid- and autohydrolysis

Abstract

Aspen wood chip samples were subjected to hot water treatments (autohydrolysis) with and without sulfuric acid to extract hemicelluloses. A liquor-to-wood ratio of 4:1 was used at temperatures from 130° to 210°C and H2SO4 concentrations in the range from 0% to 1% (w/v), with treatment times up to 4.5 h. Researchers analyzed wood residues and their corresponding hydrolysates, and determined the most suitable conditions for the extraction. Additional information on the suitability of wood residues for pulping purposes is also considered.

A larch biorefinery: Influence of washing and PS charge on pre-extraction PSAQ pulping

“…For bleachable grade kraft pulp made from loblolly pine, a yield loss of 6% is obtained at about 8% (both on original wood) sugars in the extract , similar to 7% yield loss at about 7% extract sugars for Scots pine (Kautto et al 2010). For a bleachable grade hardwood kraft pulp, the yield loss for silver birch after a mild water hydrolysis is about 4% at 4% sugars in the water extract (Helmerius et al 2010), 10% yield loss for Eucalyptus globulus at a similar percentage of sugar extraction (Mendes et al 2009), and about 11% pulp yield loss after collecting the same level of sugars in the water extract for aspen (Al-Dajani et al 2009).…”

“…Recently, the focus has turned to the possibility of producing other products in addition to or even replacing paper and board (van Heiningen 2006). In one of these biorefinery concepts, the hemicelluloses are extracted before kraft pulping, and then they are utilized as feedstock for biofuels or biochemicals production, while the extracted wood chips are pulped into kraft fibers (Frederick et al 2008;Al-Dajani et al 2009;Helmerius et al 2010;Kämppi et al 2010;Vila et al 2011;Yoon et al 2011). The hemicelluloses have been used for the production of liquid fuels such as ethanol (Walton et al 2010;Liu et al 2010), butanol (Survase et al 2011), jet and diesel fuel (Xing et al 2010), and gasoline (Li et al 2011).…”

Lignocellulosics as sustainable resources for production of bioplastics – A review

“…In recent years, fractionation of the other main lignocellulosic components has been emphasized in the biorefinery context. Thus, several studies have been conducted about separation of hemicelluloses and partial lignin utilization (Al-Dajani et al, 2009;Yoon et al, 2010Yoon et al, , 2011Chirat et al, 2010;Schild et al, 2010). Importantly, some industrial ventures have been established, implementing some of these processes (Miller and Faleiros, 2016).…”