5179021 Pulp bleaching process comprising oxygen delignification and xylanase enzyme treatment

1993 ◽  
Vol 11 (2) ◽  
pp. 348-349
Keyword(s):  
Enzyme Treatment ◽  
Oxygen Delignification ◽  
Pulp Bleaching ◽  
Bleaching Process ◽  
Xylanase Enzyme

scholarly journals DISSOLVING PULP FROM KENAF BY BIO-BLEACHING PROCESS

2016 ◽  
Vol 3 (02) ◽  
Author(s):  
Susi Sugesty ◽  
Yusup Setiawan
Keyword(s):  
Chlorine Dioxide ◽  
Fibre Length ◽  
Dissolving Pulp ◽  
Raw Material ◽  
National Standard ◽  
Cellulose Content ◽  
Oxygen Delignification ◽  
Pulp Bleaching ◽  
Bleaching Process ◽  
Cooking Liquor

The kenaf taken from Malang-East Java was four to five months old and used as the raw material of dissolving pulp. Morphology and chemicals content of kenaf was analyzed based on Indonesian National Standard (SNI). Kenaf fibre has the fibre length average of 2.59 mm for stem and 3.63 mm for bast and it is classified on the long fiber, fibre length > 1.60 mm. It contains alpha cellulose in the amount of 45.45% for bast and 39.46% for stem. Kenaf was cut with the length of 3 to 5 cm to make chips. Before cooking, pre-hydrolyzed using water and dilute acid (0.4% H2SO4) was done to remove pentosan (hemicellulose) by soaking chips in water and 0.4% H2SO4 in the ratio of 1 : 5 at temperature of 135oC for 2 hours. The results was mixed with cooking liquor which contains Active Alkali (AA) of 16% and Sulfidity (S) of 28%. Ratio of raw material and cooking liquor was 1 : 5 at temperature of 160oC for 3 hours. Bleaching process was done in the five stages consisted of X0D0E0D1D2 (Xylanase, Oxygen delignification, Chlorine Dioxide, Oxygen Ectraction, Chlorine Dioxide 1st, Chlorine Dioxide 2nd). Bleaching process in the stage of X use xylanase enzyme (bio-bleaching). Every stage was washed with hot soft water up to neutral pH. Dissolving pulp was analyzed for brightness, alpha cellulose content and other chemicals content. Pulp viscosity is very high, which means that the pulp bleaching process is not much cause degraded cellulose Keywords: bio-bleaching, dissolving pulp, pre-hydrolyzed, kenaf, xylanase  ABSTRAKKenaf berasal dari daerah Jawa Timur Malang - berusia empat sampai lima bulan dan digunakan sebagai bahan baku dissolving pulp. Morfologi dan komponen kimia kenaf dianalisis berdasarkan Standar Nasional Indonesia (SNI). Serat kenaf memiliki panjang serat rata-rata 2,59 mm untuk batang dan 3,63 mm untuk kulit pohon, termasuk kedalam kelompok serat panjang dengan panjang serat > 1,60 mm. Kenaf mengandung alpha selulosa sebesar 45,45% untuk kulit dan 39,46% untuk batang. Kenaf dipotong-potong dengan panjang 3 sampai dengan 5 cm. Sebelum pemasakan, dilakukan prahidrolisa menggunakan air dan asam encer (0,4% H2SO4) untuk melunakkan serpih kenaf dan membuat ikatan pentosan (hemiselulosa) menjadi lemah, dengan merendamnya dalam air dan 0,4% H2SO4 dengan rasio 1 : 5 pada suhu 135oC selama 2 jam. Selanjutnya dilakukan pemasakan dengan proses kraft menggunakan Alkali Aktif (AA) sebesar 16% dan sulfiditas (S) sebesar 28%. Rasio bahan baku dan larutan pemasak adalah 1 : 5 pada suhu 160oC selama 3 jam. Proses pemutihan pulp dilakukan dalam lima tahap terdiri dari X0D0E0D1D2 (Xilanase, Oksigen delignifikasi, Klorin dioksida, Oksigen Ekstraksi, Klorin dioksida 1, Klorin dioksida 2). Proses pemutihan pada tahap X menggunakan enzim xilanase yang dikenal dengan bio–bleaching. Setiap tahap dicuci dengan air panas sampai bersih. Dissolving pulp yang diperoleh dianalisis derajat cerah, kadar selulosa alfa dan komponen kimia lainnya sesuai SNI. Dissolving pulp mempunyai viskositas yang sangat tinggi, ini berarti bahwa proses pemutihan pulp tidak banyak menyebabkan terjadinya degradasi selulosa.Kata kunci: bio-bleaching, dissolving pulp, prehidrolisa, kenaf, xilanase

Study on Magnesium Hydroxide-Based Hydrogen Peroxide Bleaching Process of Nigra poplar CTMP

2011 ◽  
Vol 233-235 ◽  
pp. 1328-1331 ◽  
Author(s):  
Qiang Zhao ◽  
De Zhi Sun ◽  
Ming Yang Zhang ◽  
Su Min Kang
Keyword(s):  
Hydrogen Peroxide ◽  
Reaction Time ◽  
Magnesium Hydroxide ◽  
High Yield ◽  
Pulp Yield ◽  
Pulp Bleaching ◽  
Bleaching Process ◽  
Peroxide Bleaching ◽  
Bleaching Condition ◽  
Pulp Consistency

The Mg(OH)2-based peroxide bleaching process of Nigra poplar CTMP pulp was confirmed. The optimal bleaching condition were as follows: 4% H2O2,1% Mg(OH)2, 15% pulp consistency, the reaction temperature was 80°C and the suitable reaction time was 2 hours. The Mg(OH)2-based bleaching process shows significant benefits over sodium hydroxide process. In contrast, magnesium hydroxide bleaching generates higher pulp yield and lower effluent COD at the same chemical dosage. The study shows peroxide bleaching of CTMP pulp with magnesium hydroxide as alkali source is to be an option for the high-yield pulp bleaching.

Ozone bleaching of South African Eucalyptus grandis kraft pulps containing high levels of hexenuronic acids

TAPPI Journal ◽  
2013 ◽  
Vol 12 (8) ◽  
pp. 9-16 ◽  
Author(s):  
JEROME E. ANDREW ◽  
JONAS JOHAKIMU ◽  
NKANYISO E. NGEMA
Keyword(s):  
South African ◽  
Chlorine Dioxide ◽  
Preliminary Investigation ◽  
Eucalyptus Grandis ◽  
Reference Sequence ◽  
Kraft Pulps ◽  
Oxygen Delignification ◽  
Pulp Bleaching ◽  
Brightness Reversion ◽  
Removal Efficiencies

Ozone use in conjunction with chlorine dioxide during pulp bleaching offers several advantages over conventional bleaching sequences that make use of chlorine dioxide only. Despite this, in South Africa, only one mill uses ozone. The current study was a preliminary investigation into the use of ozone in bleaching sequences for kraft pulps produced from South African Eucalyptus grandis wood chips, which typically contained high amounts of hexenuronic acids (HexA). The objective of the study was to compare the performance of ozone to other technologies used to remove HexA, such as acid hydrolysis (A) and hot chlorine dioxide (DHT) stages. Bleaching sequences using chlorine dioxide (i.e., OAD0ED1D2 and ODHTED1D2) were compared to bleaching sequences using ozone (i.e., OZD0ED1 and OAZD0ED1). The results showed that ozone preferentially reacted with HexA in the presence of lignin. When applied after oxygen delignification, ozone had the same HexA removal efficiencies as the A- and DHT- stages at dosages in excess of 0.6%. When used in combination with the A-stage, the HexA removal efficiencies of ozone reached 96%. Consequently, up to 15% savings in the estimated bleaching chemical costs were achieved when the OAZD0(EP)D sequence was used, compared to the standard reference sequence (OAD0ED1D2). The residual HexA in the bleached pulp affected brightness reversion of the pulps, but this was only evident for the bleaching sequences that used chlorine dioxide, not for those that included ozone.

Quantification of lignin-carbohydrate complexes in hardwood pulps, Part 2: Effects of bleaching chemicals

TAPPI Journal ◽  
2015 ◽  
Vol 14 (10) ◽  
pp. 663-670 ◽  
Author(s):  
DAVID J. NICHOLSON ◽  
GUSTAVO V. DUARTE ◽  
ERICKA F. ALVES ◽  
DAVID J. KIEMLE ◽  
AARON T. LEAVITT ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Chlorine Dioxide ◽  
Acer Saccharum ◽  
Sugar Maple ◽  
Kappa Number ◽  
Oxygen Delignification ◽  
Bleaching Process ◽  
Lignin Removal ◽  
Dilute Sodium Hydroxide ◽  
Alkaline Conditions

High kappa number kraft and soda-anthraquinone (soda-AQ or SAQ) pulps from sugar maple (Acer saccharum) were investigated to see how the lignin-carbohydrate complexes (LCC) they contained affected lignin removal by oxygen, chlorine dioxide, and hydrogen peroxide. The chlorine dioxide and hydrogen peroxide doses were higher than normal because both pulps had unbleached kappa numbers in the range of 61-62. Only oxygen delignification was investigated with the SAQ pulp. The research focused on the strong lignin-carbohydrate (L-C) linkages only. The pulp carbohydrates were enzymatically degraded and solubilized, thus leaving an enzymatic lignin (EL) residue. The highest concentration of bound sugars (glucan, xylan, arabinan, and galactan) on any of the ELs was <2.1 wt%. Chlorine dioxide (D stage) was investigated at end pHs of 2.1, 2.9, and 4.0, followed by extraction with dilute sodium hydroxide. Lignin oligomers containing bound glucan and arabinan were unreactive and accumulated in the fibers. When oxygen was used to delignify kraft and SAQ pulps by ~50%, only ~10% of the lignin bound arabinan was solubilized. Galacto-lignin complexes were somewhat reactive to oxygen and hydrogen peroxide under alkaline conditions, but less reactive in the D stages. Consistent with literature data, xylo-lignin complexes were reactive toward oxygen and toward the other two oxidants. They do not appear to be major impediments in the bleaching process.

Fundamental molecular characterization and comparison of the O, D0, and E stage effluents from hardwood pulp bleaching

TAPPI Journal ◽  
2019 ◽  
Vol 18 (6) ◽  
pp. 341-351 ◽  
Author(s):  
JULIANA JARDIM ◽  
XUEYU DU ◽  
PETER HART ◽  
LUCIAN LUCIA ◽  
HASAN JAMEEL ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Molecular Weight Distribution ◽  
Weight Distribution ◽  
Gel Permeation Chromatography ◽  
High Yield ◽  
Lower Amount ◽  
Oxygen Delignification ◽  
Pulp Bleaching ◽  
Dissolved Organics ◽  
Hardwood Pulp

The present study characterized effluents from the O, D0, and E stages using nuclear magnetic resonance (NMR) and gel permeation chromatography (GPC) techniques to better understand the chemical nature of the dissolved organics formed from the bleaching of a high-yield hardwood kraft pulp. Understanding the structures and molecular weight distribution of these organics is the first step in developing methods to mitigate these contaminates in the discharged effluents. The results indicated that the molecular weight distribution (MWD) of the dissolved organics from oxygen delignification effluent is broader than those from D0 and E stage effluents. In addition, the O stage filtrate contained considerable amounts of lignin and xylan fragments, which showed its efficiency in removing such materials. The effluent from the D0 stage contained a lower amount of high molecular weight fragments and a higher amount of low molecular weight fragments versus the O-stage filtrate. Aromatic structures were nearly absent in the D0 stage filtrate, but the degraded organic material, presumably from oxidized lignin, contained olefinic (C=C) and carbonyl (C=O) functional groups. Furthermore, higher molecular weight fragments were detected in the E-stage effluent, presumably due to the extensive solubilization and removal of the oxidized lignin generated from the D0 pulp.

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