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  • 1
    Language: English
    In: Bioresource Technology, Oct, 2014, Vol.169, p.155(7)
    Description: To link to full-text access for this article, visit this link: http://dx.doi.org/10.1016/j.biortech.2014.06.091 Byline: Qingxi Hou, Yang Wang, Wei Liu, Lihui Liu, Ningpan Xu, Yang Li Abstract: acents Poplar wood chips were autohydrolyzed prior to chemi-thermomechanical pulping. acents Effects of autohydrolysis on chemical compositions in the AHL were investigated. acents A 44% of the extraction yield for xylose from poplar wood chips can be obtained. acents Autohydrolysis pretreatment prior to CTMP was helpful to refining energy savings. acents Some properties of the resultant pulp made from the hydrolyzed chips were improved. Article History: Received 3 May 2014; Revised 24 June 2014; Accepted 25 June 2014
    Keywords: Energy Conservation
    ISSN: 0960-8524
    Source: Cengage Learning, Inc.
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  • 2
    Language: English
    In: Bioresource Technology, October 2014, Vol.169, pp.155-161
    Description: This study investigated the autohydrolysis pre-treatment prior to chemi-thermomechanical pulping (CTMP) process including the effects of autohydrolysis pretreatment with a lower severity on characteristics of the autohydrolysis liquor and hydrolyzed chips. The intensity of autohydrolysis, characterized by the severity factor, increased from 1.76 to 3.54, the hydrolyzed chips yield decreased from 99.0% to 86.7% and the xylose extraction yield increased from 0.8% to 44.0%. The content of holocellulose, pentosan and acid soluble lignin remained in the hydrolyzed chips decreased dramatically with increasing the treatment severity. After the autohydrolysis pretreatment, the resultant poplar chemi-thermomechanical pulp with a severity factor of 2.37 could obtain a 15.3 N m/g tensile index, 58.6% ISO brightness and a 2.39 cm /g bulk.
    Keywords: Autohydrolysis ; Chemi-Thermomechanical Pulping (Ctmp) ; Severity Factor ; Chemical Compositions ; Physical Properties ; Agriculture ; Engineering ; Chemistry
    ISSN: 0960-8524
    E-ISSN: 1873-2976
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  • 3
    Language: English
    In: Industrial & Engineering Chemistry Research, 02/26/2014, Vol.53(8), pp.2897-2902
    Description: Some of the dissolved and colloidal substances (DCS) such as extractives and pectic acids have great negative influence through the whole papermaking process, and their control and understanding would benefit the production, especially in the mills with closed water system. In this work, the DCS from the alkaline peroxide bleaching of poplar chemi-thermomechanical pulp (CTMP) with partial substituting MgO for NaOH were analyzed. The results showed that the amount, pH value, lignin content, conductivity, and cationic demand (CD) of the DCS decreased with increasing substitution percentage of MgO for NaOH. The methyl tert-butyl ether (MTBE) extractives were characterized by a gas chromatograph coupled to a mass spectrometry (GC-MS). The substitution of MgO for NaOH in the bleaching process improves the bulk, light-scattering coefficient, and opacity of the bleached poplar CTMP, reduces the pulp brightness, and decreases the tensile and burst indices.
    Keywords: Water Pollution ; Mass Spectrometry ; Acids ; Conductivity ; Pulp and Paper Industry ; Opacity ; Ethers ; Benefits ; Water Pollution ; Mass Spectrometry ; Acids ; Conductivity ; Pulp and Paper Industry ; Opacity ; Ethers ; Benefits ; General ; Water Resources and Supplies;
    ISSN: 0888-5885
    E-ISSN: 1520-5045
    Source: American Chemical Society (via CrossRef)
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  • 4
    Language: English
    In: Industrial & Engineering Chemistry Research, 08/29/2012, Vol.51(34), pp.11122-11127
    Description: Pre-extraction of hemicelluloses prior to pulping and conversion of the extracted hemicelluloses to other byproducts will provide additional revenue to the traditional pulp and paper industry. The effect of hemicelluloses pre-extraction with dilute sulfuric acid on the properties and bleachability of aspen (Populus tremuloides) chemithermomechanical pulp (CTMP) was investigated. The acid pre-extraction significantly reduced refining energy consumption to a given freeness. However, at the same freeness, the acid pre-extraction resulted in the reduction of bulk, tensile index, and zero-span breaking length, fewer long fibers and more fines, but an increase of the Scott bond strength. Alkaline peroxide bleaching can compensate the strength loss, but the bleachability of pulps with acid pre-extraction was lower than that of the control.
    Keywords: Paper Mills ; Reduction ; Pulping ; Revenues ; Refining ; Breaking ; Bleaches ; Long Fibers ; Analysis (MD) ; Chemical Analysis (Ep) ; Chemical Analysis (Ed) ; Chemical Analysis (EC);
    ISSN: 0888-5885
    E-ISSN: 1520-5045
    Source: American Chemical Society (via CrossRef)
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  • 5
    Language: English
    In: Bioresource Technology, April 2016, Vol.206, pp.99-103
    Description: The hardwood bleached kraft pulp (HBKP) fibers were pretreated by PFI mill to obtain the substrates, the effects of fibrillation on HBKP fibers’ enzymatic hydrolysis was studied. The results showed that the enzymatic hydrolysis efficiency was enhanced obviously by mechanical refining. The mechanical refining alterated the fibers’ characteristics such as fibrillation degree, specific surface area, swelling ability, crystallinity, fiber length and fines content. All these factors correlating to the enzymatic hydrolysis were evaluated through mathematical analysis. Among these factors, the fibrillation degree has the profoundest impact on the enzymatic hydrolysis of wood fibers. Consequently, the mechanical refining aiming for a high fibrillation degree was feasible to enhance the enzymatic hydrolysis of lignocellulosic biomass.
    Keywords: Mechanical Refining ; Fibrillation ; Enzymatic Hydrolysis ; Conversion ; Agriculture ; Engineering ; Chemistry
    ISSN: 0960-8524
    E-ISSN: 1873-2976
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  • 6
    Language: English
    In: Bioresource Technology, September 2016, Vol.216, pp.317-322
    Description: Autohydrolysis with different severity factors was performed on poplar wood chips prior to pulping, and the wettability, absorbility and the following impregnation of NaOH solution for the poplar wood chips were then investigated. The results showed that after autohydrolysis pretreatment the porosity, shrinkage and fiber saturation point (FSP) of the poplar wood chips were increased, while the surface contact angle decreased as the severity factor was increased. The autohydrolyzed chips absorbed more NaOH in impregnation that resulted in a low NaOH concentration in the bulk impregnation liquor (i.e., the impregnation liquor outside wood chips), while the concentration in the entrapped liquor (i.e., the impregnation liquor inside wood chips) was increased. Autohydrolysis substantially improved the effectiveness of alkali impregnation.
    Keywords: Autohydrolysis ; Impregnation ; Poplar Wood Chips ; Absorption ; Agriculture ; Engineering ; Chemistry
    ISSN: 0960-8524
    E-ISSN: 1873-2976
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  • 7
    Language: English
    In: Bioresource Technology, March 2017, Vol.228, pp.125-132
    Description: Dilute acid pre-extraction enhanced the mechanically refined poplar pulp substrates’ enzymatic hydrolysis efficiency obviously. The results showed that the surface lignin distribution was changed significantly in residual wood chips and pulp substrates, and the surface lignin distribution showed important impact on the following enzymatic hydrolysis. Acid pre-extraction can lead to a redistribution of lignin in fiber cell walls, i.e., the lignin was degraded and migrated to fiber surface in the form of re-deposited lignin and pseudo-lignin. However, higher pre-extraction intensity was not desired due to the formation of redeposited lignin and pseudo-lignin. This study will help to reach a deeper understanding on the lignin distribution in the view of molecular and ultrastructure, and promote the development of a cost-efficient pretreatment strategy for biomass processing.
    Keywords: Dilute Acid Pre-Extraction ; Mechanical Refining ; Surface Lignin Concentration ; Redistribution ; Enzymatic Hydrolysis ; Agriculture ; Engineering ; Chemistry
    ISSN: 0960-8524
    E-ISSN: 1873-2976
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  • 8
    Language: English
    In: Bioresource Technology, December 2016, Vol.222, pp.361-366
    Description: This work is aimed at investigating the influence of changes in the content of hemicelluloses of the autohydrolyzed poplar sapwood on the subsequent alkali impregnation for chemi-mechanical pulping (CMP). An alkali impregnation process was conducted using the autohydrolyzed poplar sapwood with different content of hemicelluloses as raw materials. The results showed that both the amount of NaOH consumption and swelling degree of poplar sapwood increased with the removal of hemicelluloses, thus enhancing the alkali impregnation effectiveness. The hemicelluloses removal can also shorten the alkali impregnation time for the autohydrolyzed poplar sapwood to achieve the similar impregnation effectiveness of unautohydrolyzed poplar sapwood. All of these can be attributed to the fact that the hemicelluloses removal would result in the exposure of more free hydroxyl groups on the cellulose and an increase in the porosity of the fiber cell walls.
    Keywords: Poplar Sapwood ; Autohydrolysis ; Alkali Impregnation ; Hemicelluloses ; Wood Swelling ; Agriculture ; Engineering ; Chemistry
    ISSN: 0960-8524
    E-ISSN: 1873-2976
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  • 9
    Language: English
    In: Bioresource Technology, November 2015, Vol.196, pp.662-667
    Description: Autohydrolysis pretreatment with different severity factors was performed on poplar chips prior to chemi-thermomechanical pulping (CTMP) in order to investigate the change in pH value and its effect on the autohydrolysis pretreatment. The results showed that the dissolution amount of acetic acid increased with raising the severity factor of the pretreatment and declining the size of poplar chips, respectively. Besides, a logarithmic relationship between the amount of acetic acid released in the autohydrolysis liquor (AHL) and pH value of the AHL was observed. The amounts of glucose and xylose (including those in the form of monomers, oligomers, and polysaccharides) as well as furfural and hydroxymethylfurfural (HMF) also depended on the pH value of the AHL to some extent.
    Keywords: Autohydrolysis ; Acetic Acid ; Ph Value ; Chemi-Thermomechanical Pulping (Ctmp) ; Agriculture ; Engineering ; Chemistry
    ISSN: 0960-8524
    E-ISSN: 1873-2976
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  • 10
    Language: English
    In: Journal of agricultural and food chemistry, 16 May 2012, Vol.60(19), pp.4880-5
    Description: 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.
    Keywords: Betula -- Chemistry ; Plant Extracts -- Chemistry ; Polysaccharides -- Chemistry ; Wood -- Chemistry
    ISSN: 00218561
    E-ISSN: 1520-5118
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