scholarly journals Effect of xylanase pretreatment on the kraft pulping of poplar

BioResources ◽  
2020 ◽  
Vol 16 (1) ◽  
pp. 979-986
Author(s):  
Mehmet Akgül ◽  
Mehmet Onurhan Gücüş ◽  
Birol Üner ◽  
Celil Atik
Keyword(s):  
Mechanical Properties ◽  
Optical Properties ◽  
Kraft Pulp ◽  
Lignin Content ◽  
Kraft Pulping ◽  
Wood Chips ◽  
Populus X Euramericana ◽  
Cooking Conditions

This study aimed to determine the influence of prehydrolysis of wood chips on the kraft pulping of Populus x euramericana. Optimum cooking conditions were determined by evaluating different alkali concentrations and cooking periods. Xylanase was used to hydrolyze chips before cooking. Prehydrolysis process increased the yield and viscosity of pulp. Consequently, the mechanical properties of paper changed remarkably. In contrast, the optical properties of the unbleached kraft pulp declined due to lignin content.

Semi-bleached paper and fermentation products from a larch biorefinery

TAPPI Journal ◽  
2012 ◽  
Vol 11 (10) ◽  
pp. 31-39 ◽  
Author(s):  
HANNA HÖRHAMMER ◽  
OKSANA BEREZINA ◽  
EERO HILTUNEN ◽  
TOM GRANSTRÖM ◽  
ADRIAAN VAN HEININGEN
Keyword(s):  
Kraft Pulp ◽  
Siberian Larch ◽  
Kraft Pulping ◽  
Larix Sibirica ◽  
Wood Chips ◽  
Paper Properties ◽  
Fermentation Products ◽  
Kraft Paper

This study was focused on the products from a larch biorefinery, specifically bleached paper and different fermentation products. Siberian larch (Larix sibirica Lebed.) wood chips were treated with water in a pre-extraction (PE) stage. The larch extract was removed by drainage and fermented into different products. Eight different bacteria strains were tested. The extracted wood chips were mildly washed before kraft pulping with polysulfide (PS) and anthraquinone (AQ). The PE-PSAQ pulps were bleached to about 80% brightness. Laboratory paper sheets were made and tested for different paper properties, and a conventional larch kraft pulp was also prepared as reference. The larch PE-PSAQ paper and the larch kraft paper had similar properties. The removal of a significant amount of hemicelluloses from the wood chips before pulping was not a detriment to the paper properties.

Characteristics of prehydrolysis-kraft pulp fibers from Scots pine

Holzforschung ◽  
2012 ◽  
Vol 66 (7) ◽  
pp. 801-808 ◽  
Author(s):  
Esa Saukkonen ◽  
Jesse Kautto ◽  
Irina Rauvanto ◽  
Kaj Backfolk
Keyword(s):  
Scots Pine ◽  
Chlorine Dioxide ◽  
Kraft Pulp ◽  
Kraft Pulping ◽  
Hot Water ◽  
Wood Chips ◽  
Pulp Fibers ◽  
Fiber Dimensions ◽  
End Use ◽  
Prehydrolysis Kraft

Abstract To clarify the influence of prehydrolysis on fiber characteristics, Scots pine (Pinus sylvestris L.) wood chips were subjected to pressurized hot-water and dilute-acid prehydrolysis (0.5% H2SO4) prior to kraft pulping to partially remove hemicelluloses as hydrolyzate. After the prehydrolysis, the wood chips were submitted to kraft pulping and the pulp was fully bleached in oxygen (O), chlorine dioxide (D), alkaline extraction (E) and chlorine dioxide (D)-sequence. Measurements with an automated optical fiber analyzer showed that prehydrolysis prior to kraft pulping caused significant changes in the fiber dimensions and morphology of the final bleached pulp. Especially, a decrease in fiber width and an increase in fiber deformations were observed compared to a reference kraft pulp. The scanning electron microscopy of handsheets supported the morphology analyses and revealed alterations also in the fiber ultrastructure. The changes in both chemical and physical fiber characteristics require attention when considering the correct processing and end-use of prehydrolysis-kraft pulp fibers.

scholarly journals Effect of mechanical and chemical pulping on ionic liquid fractionation of wood chips

2019 ◽  
Author(s):  
◽  
Nhlanhla Hlongwa
Keyword(s):  
Ionic Liquid ◽  
Kraft Pulp ◽  
Thermo Gravimetric Analysis ◽  
Wood Chip ◽  
Kraft Pulping ◽  
Wood Chips ◽  
Regenerated Cellulose ◽  
Gravimetric Analysis ◽  
Mechanical Pulp ◽  
G Ratio

In this study, a comparison of two pulping methods namely mechanical and chemical, on the dissolution of Eucalyptus grandis (E. grandis) wood chips was undertaken. The wood chip pulp was treated with an ionic liquid (IL): 1-allyl-3-methylimidazolium chloride to extract the cellulose. The IL was mixed with unbleached mechanical pulp (UBMP), bleached mechanical pulp (BMP), unbleached kraft pulp (UBKP) and bleached kraft pulp (BKP) in ratios of 10%, 20%, 30%. Each solution contained IL, wood pulp and 2-mL of 16 v/v % of dimethyl sulfoxide (DMSO). The 30 % IL pretreatment was the most effective IL pretreatment. The cellulose yield at 30 % IL pretreatment for UBMP, BMP, UBKP and BKP was 65.12%, 63.82%, 67.43%, 67.15%, respectively. This indicated that the kraft pulping method was more effective than the mechanical pulping method for the yield of cellulose after the IL pretreatment. The Crl value at 30 % IL pretreatment was highest for UBMP (72.03%) indicating that the pretreatment used was the least effective in reducing the cellulose crystallinity. The fractions of E. grandis wood chip namely, lignin, regenerated cellulose and hemicelluloses before and after the IL pretreatment, were characterized by a variety of analytical techniques such as High-Performance Liquid Chromatography (HPLC) (carbohydrates), Fourier Transform Infra-Red Attenuated Total Reflection (FTIR-ATR) (functional groups), Pyrolysis-Gas Chromatography /Mass Spectroscopy (Py-GC/MS) (lignin fractions), Ultraviolet/Visible spectroscopy (UV/Vis) (acid soluble lignin), Thermo Gravimetric Analysis (TGA) (degradation of pulp), X-Ray Diffraction (XRD) (crystallinity) and high resolution Scanning Electron Microscopy (SEM) (morphology). Kraft pulping was the most effective method for the yield of cellulose after the [AMIM][Cl]/DMSO pretreatment. The 30% [AMIM][Cl]/DMSO pretreatment gave the highest S/G ratio indicating that minimal bleaching was required.

scholarly journals H2O2 bleaching of brown pulp with adsorbed xylan and its modifying effects on the mechanical properties of paper

BioResources ◽  
2021 ◽  
Vol 16 (4) ◽  
pp. 6814-6830
Author(s):  
Xue Zhang ◽  
Lizi Li ◽  
Junfei Tian ◽  
Nanhua Li ◽  
Leigang Zuo ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Hydrogen Peroxide ◽  
Optical Properties ◽  
Kraft Pulp ◽  
Current Trend ◽  
Paper Properties ◽  
Effective Utilization ◽  
Bleaching Process ◽  
Hardwood Species ◽  
Initial Ph

Xylan is the primary hemicellulose in most hardwood species, especially in birch. Research has highlighted the exploitation of xylans as a strength-enhancing additive to paper due to the current trend for the effective utilization of biomass. In this paper, a new pulping process was proposed, which involved the extraction of xylan prior to pulping, followed by the re-adsorption of the pulp after the final stage in the digester, followed by a suitable bleaching process. The aim of this work was to bleach hardwood kraft pulp (brown pulp) with adsorbed birch xylan via hydrogen peroxide and study the effect of the bleaching parameters on the paper properties. The results showed that the optical properties of paper decreased; however, the mechanical properties increased after the brown pulp adsorbed birch xylan. During the bleaching process, better mechanical properties were obtained with shorter bleaching times and lower bleaching temperatures, initial pHs, and MgSO4 dosages. However, the optical properties were improved as the bleaching time, temperature, initial pH, and MgSO4 dosage were increased. The adsorption of birch xylan could effectively modify the mechanical properties of paper made from brown pulp under various phases.

Lignin chemistry and topochemistry during kraft delignification of Eucalyptus globulus genotypes with contrasting pulpwood characteristics

Holzforschung ◽  
2014 ◽  
Vol 68 (6) ◽  
pp. 623-629 ◽  
Author(s):  
María Graciela Aguayo ◽  
André Ferraz ◽  
Juan Pedro Elissetche ◽  
Fernando Masarin ◽  
Regis Teixeira Mendonça
Keyword(s):  
Chemical Composition ◽  
Eucalyptus Globulus ◽  
Lignin Content ◽  
Middle Lamella ◽  
Kraft Pulping ◽  
Pulp And Paper ◽  
Wood Chips ◽  
Short Fibre ◽  
Paper Production ◽  
Cell Corner

Abstract Eucalyptus globulus Labill. is a short-fibre resource for pulp and paper production. Ten different E. globulus genotypes with varied pulpwood quality and chemical composition were evaluated under kraft pulping conditions. Characterisation of the wood and pulp samples by thioacidolysis indicated that the content of syringyl units in β-O-4 linkages (S-β-O-4) was distinct for the studied genotypes. The highest S-β-O-4 levels were detected in the samples with the lowest original lignin and highest glucan levels. This group of samples provided the pulps with the lowest final lignin content at higher yields. UV microspectrophotometric (UMSP) evaluation of the wood chips revealed that the samples with the lowest lignin levels have the lowest UV absorbances at 278 nm (A278 nm) in the secondary walls (S2). During kraft pulping, lignin from the S2 was dissolved, whereas lignins from the middle lamella and cell corner lignin was not removed not even for prolonged reaction periods, independently of the evaluated genotype. The A278 nm values of the S2 were significantly lower in the pulps from the genotypes with less original lignin content.

scholarly journals Lipid and lignin composition of woods from different eucalypt species

Holzforschung ◽  
2007 ◽  
Vol 61 (2) ◽  
pp. 165-174 ◽  
Author(s):  
Jorge Rencoret ◽  
Ana Gutiérrez ◽  
José C. del Río
Keyword(s):  
Eucalyptus Globulus ◽  
Lignin Content ◽  
Kraft Pulping ◽  
Medium Length ◽  
Eucalypt Species ◽  
Kraft Cooking ◽  
Lignin Composition ◽  
G Ratio ◽  
Cooking Conditions

Abstract The lipid and lignin compositions of woods from the eucalypt species Eucalyptus globulus, E. nitens, E. maidenii, E. grandis, and E. dunnii have been characterized. The lipid composition was analyzed by GC and GC/MS using short- and medium-length high-temperature capillary columns, which allowed the detection of intact high-molecular-weight compounds. Similar lipid compositions were observed in all eucalypt woods, which were dominated by sitosterol, sitosterol esters and sitosteryl 3β-D-glucopyranoside. These substance classes are mainly responsible for pitch deposition during kraft pulping of eucalypt wood. However, some quantitative differences were found in the abundance of different lipid classes, with wood from E. globulus containing the lowest amounts of these pitch-forming compounds. The lignins of all eucalypt woods were analyzed in situ (without previous isolation) by pyrolysis-GC/MS. A predominance of syringyl (S) over guaiacyl (G) lignin units was observed and the S/G ratio was in the range from 2.7 to 4.1. E. globulus wood had the highest S/G ratio, a finding that, together with its low lignin content, explains its easy delignification under kraft cooking conditions.

scholarly journals DFT Study of Electronic Structure and Optical Properties of Kaolinite, Muscovite, and Montmorillonite

Crystals ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 618
Author(s):  
Layla Shafei ◽  
Puja Adhikari ◽  
Wai-Yim Ching
Keyword(s):  
Mechanical Properties ◽  
Optical Properties ◽  
Electronic Structure ◽  
Hydrogen Bonds ◽  
Clay Minerals ◽  
Clay Mineral ◽  
Bond Order ◽  
Deep Understanding ◽  
Pharmaceutical Applications ◽  
Structure Properties

Clay mineral materials have attracted attention due to their many properties and applications. The applications of clay minerals are closely linked to their structure and composition. In this paper, we studied the electronic structure properties of kaolinite, muscovite, and montmorillonite crystals, which are classified as clay minerals, by using DFT-based ab initio packages VASP and the OLCAO. The aim of this work is to have a deep understanding of clay mineral materials, including electronic structure, bond strength, mechanical properties, and optical properties. It is worth mentioning that understanding these properties may help continually result in new and innovative clay products in several applications, such as in pharmaceutical applications using kaolinite for their potential in cancer treatment, muscovite used as insulators in electrical appliances, and engineering applications that use montmorillonite as a sealant. In addition, our results show that the role played by hydrogen bonds in O-H bonds has an impact on the hydration in these crystals. Based on calculated total bond order density, it is concluded that kaolinite is slightly more cohesive than montmorillonite, which is consistent with the calculated mechanical properties.

Fate of phosphorus in the recovery cycle of the kraft pulping process

TAPPI Journal ◽  
2020 ◽  
Vol 19 (3) ◽  
pp. 139-148
Author(s):  
MARYAM SADEGH MOUSAVI ◽  
NIKOLAI DEMARTINI
Keyword(s):  
Kraft Pulp ◽  
Pulp Mill ◽  
Field Studies ◽  
Kraft Pulping ◽  
Pulp Mills ◽  
Recovery Cycle ◽  
Green Liquor ◽  
Green Liquor Dregs ◽  
Kraft Pulp Mills ◽  
Negative Effect

The accumulation of nonprocess elements in the recovery cycle is a common problem for kraft pulp mills trying to reduce their water closure or to utilize biofuels in their lime kiln. Nonprocess elements such as magne-sium (Mg), manganese (Mn), silicon (Si), aluminum (Al), and phosphorus (P) enter the recovery cycle via wood, make-up chemicals, lime rock, biofuels, and process water. The main purge point for these elements is green liquor dregs and lime mud. If not purged, these elements can cause operational problems for the mill. Phosphorus reacts with calcium oxide (CaO) in the lime during slaking; as a result, part of the lime is unavailable for slaking reactions. The first part of this project, through laboratory work, identified rhenanite (NaCa(PO4)) as the form of P in the lime cycle and showed the negative effect of P on the availability of the lime. The second part of this project involved field studies and performing a mass balance for P at a Canadian kraft pulp mill.

Sign in / Sign up

Export Citation Format

Share Document