Impact of modifying conventional chlorine dioxide stage to hot chlorine dioxide during rice straw pulp bleaching on pulp, paper and effluent characteristics

Cellulose ◽  
2019 ◽  
Vol 26 (12) ◽  
pp. 7469-7482
Author(s):  
Daljeet Kaur ◽  
Nishi K. Bhardwaj ◽  
Rajesh Kumar Lohchab
Keyword(s):  
Rice Straw ◽  
Chlorine Dioxide ◽  
Pulp Bleaching ◽  
Pulp Paper ◽  
Effluent Characteristics

Elemental chlorine-free bleaching of North American hardwood kraft pulps: Evaluation of oxidant-reinforced extraction variables on overall bleaching optimization

TAPPI Journal ◽  
2013 ◽  
Vol 12 (10) ◽  
pp. 33-41 ◽  
Author(s):  
BRIAN N. BROGDON
Keyword(s):  
Response Surface ◽  
Chlorine Dioxide ◽  
North American ◽  
Yield Loss ◽  
Alkaline Extraction ◽  
Kraft Pulps ◽  
Pulp Bleaching ◽  
Response Surface Models ◽  
Elemental Chlorine ◽  
Surface Models

This investigation evaluates how higher reaction temperatures or oxidant reinforcement of caustic extraction affects chlorine dioxide consumption during elemental chlorine-free bleaching of North American hardwood pulps. Bleaching data from the published literature were used to develop statistical response surface models for chlorine dioxide delignification and brightening sequences for a variety of hardwood pulps. The effects of higher (EO) temperature and of peroxide reinforcement were estimated from observations reported in the literature. The addition of peroxide to an (EO) stage roughly displaces 0.6 to 1.2 kg chlorine dioxide per kilogram peroxide used in elemental chlorine-free (ECF) bleach sequences. Increasing the (EO) temperature by Δ20°C (e.g., 70°C to 90°C) lowers the overall chlorine dioxide demand by 0.4 to 1.5 kg. Unlike what is observed for ECF softwood bleaching, the presented findings suggest that hot oxidant-reinforced extraction stages result in somewhat higher bleaching costs when compared to milder alkaline extraction stages for hardwoods. The substitution of an (EOP) in place of (EO) resulted in small changes to the overall bleaching cost. The models employed in this study did not take into account pulp bleaching shrinkage (yield loss), to simplify the calculations.

scholarly journals Effect of lignin structure on adsorbable organic halogens formation in chlorine dioxide bleaching

2019 ◽  
Vol 6 (2) ◽  
pp. 182024 ◽  
Author(s):  
Lisheng Shi ◽  
Jiayan Ge ◽  
Shuangxi Nie ◽  
Chengrong Qin ◽  
Shuangquan Yao
Keyword(s):  
Chlorine Dioxide ◽  
Model Compound ◽  
Pulp Bleaching ◽  
Model Compounds ◽  
Lignin Model Compounds ◽  
Lignin Model Compound ◽  
Lignin Model ◽  
Organic Halogens ◽  
Adsorbable Organic Halogens ◽  
Lignin Structure

Adsorbable organic halogens (AOX) are formed in pulp bleaching as a result of the reaction of residual lignin with chlorine dioxide. The natural structure of lignin is very complex and it tends to be damaged by various extraction methods. All the factors can affect the study about the mechanism of AOX formation in the reaction of lignin with chlorine dioxide. Lignin model compounds, with certain structures, can be used to study the role of different lignin structures on AOX formation. The effect of lignin structure on AOX formation was determined by reacting phenolic and non-phenolic lignin model compound with a chlorine dioxide solution. Vanillyl alcohol (VA) and veratryl alcohol (VE) were selected for the phenolic and non-phenolic lignin model compound, respectively. The pattern consumption of lignin model compounds suggests that both VA and VE began reacting with chlorine dioxide within 10 min and then gradually steadied. The volume of AOX produced by VE was significantly higher than that produced by VA for a given initial lignin model compound concentration. In a solution containing a combination of VA and VE in chlorine dioxide, VE was the dominant producer of AOX. This result indicates that the non-phenolic lignin structure was more easily chlorinated, while the phenolic lignin structure was mainly oxidized. In addition, AOX content produced in the combined experiments exceeded the total content of the two separate experiments. It suggested that the combination of phenolic and non-phenolic lignin structure can promote AOX formation.

scholarly journals PENGGUNAAN XILANASE PADA PEMUTIHAN DISSOLVING PULP Acacia crassicarpa

2015 ◽  
Vol 5 (02) ◽  
Author(s):  
Susi Sugesty ◽  
Teddy Kardiansyah ◽  
Wieke Pratiwi
Keyword(s):  
Chlorine Dioxide ◽  
Dissolving Pulp ◽  
Raw Material ◽  
National Standard ◽  
Cellulose Content ◽  
Pulp Bleaching ◽  
Elemental Chlorine ◽  
Free Process ◽  
Acacia Crassicarpa ◽  
Prehydrolysis Kraft

The use of xylanase in pulp bleaching process is intended to reduce chemicals consumption in pulp industry that still using chlorine compounds (chlorine dioxide), so the bleaching stage needs to be modified without reducing the quality of dissolving pulp. Dissolving pulp was produced from six-year-old Acacia crassicarpa as raw material by the Prehydrolysis-Kraft process, then the pulp was bleached with the ECF (elemental chlorine free) process using xylanase (X) and oxygen (O) as comparison at the early stage of bleaching. The sequences of process include X/ODEDED (xylanase or oxygen; chlorine dioxide; extraction-1; chlorine dioxide-1; extraction-2; chlorine dioxide -2). Results showed that the dissolving pulp with active alkali of 22%, sulphidity of 30%, the temperature of 165oC, and the ratio of 1:4 is the optimal condition. Cellulose content, viscosity and brightness were above 94%, 6.2 cP and 88% ISO, respectively.The dissolving pulp produced with the application of xylanase has better quality than the oxygen one, and meets the requirement according to Indonesia National Standard (SNI 0938:2010, pulp rayon).Keywords: Acacia crassicarpa, xylanase, Prehydrolysis-Kraft, dissolving pulp, rayon pulpABSTRAKPenggunaan xilanase pada proses pemutihan pulp dimaksudkan untuk mengurangi konsumsi bahan kimia yang digunakan selama ini di industri pulp, yang masih menggunakan senyawa klorin (klorin dioksida), untuk itu perlu dilakukan modifikasi pada tahap pemutihannya tanpa mengurangi kualitas dissolving pulp yang dihasilkan. Pembuatan dissolving pulp dilakukan menggunakan bahan baku kayu Acacia crassicarpa berumur 6 tahun dengan proses Prahidrolisa–Kraft, selanjutnya pulp diputihkan dengan proses ECF (Elemental Chlorine Free) menggunakan xilanase (X) dan oksigen (O) sebagai pembanding pada awal pemutihan dengan 6 tahapan proses, yaitu X/ODEDED (xilanase atau oksigen; klorin dioksida; ekstraksi-1; klorin dioksida-1; ekstraksi-2; klorin dioksida-2) dengan perlakuan oksigen sebagai pembanding. Hasil pembuatan dissolving pulp dengan alkali aktif 22%, sulfiditas 30%, suhu 165oC, rasio 1:4 adalah kondisi yang optimal. Kandungan selulosa, viskositas dan derajat cerah yang diperoleh masing-masing yaitu di atas 94%, 6,2 cP dan 88% ISO. Kualitas dissolving pulp hasil pemutihan dengan penambahan xilanase lebih tinggi daripada menggunakan oksigen dan memenuhi persyaratan spesifikasi SNI 0938:2010, pulp rayon. Kata kunci : Acacia crassicarpa, xilanase, Prahidrolisa-Kraft, dissolving pulp, pulp rayon

Optimization of elemental chlorine-free bleaching for a softwood kraft pulp – part 1: impact of oxidative extraction on chlorine dioxide stoichiometry

TAPPI Journal ◽  
2010 ◽  
Vol 9 (8) ◽  
pp. 27-35 ◽  
Author(s):  
BRIAN N. BROGDON
Keyword(s):  
Decision Making ◽  
Chlorine Dioxide ◽  
Kraft Pulp ◽  
Alkaline Extraction ◽  
Pulp Bleaching ◽  
Elemental Chlorine ◽  
Kraft Pulp Bleaching ◽  
Softwood Kraft Pulp ◽  
Chemical Usage ◽  
Minimize Costs

The present investigation meticulously analyzes how oxidative alkaline extraction can be augmented through process changes, and how these augmentations can be leveraged to optimize chlorine dioxide usage with elemental chlorine-free (ECF) sequences for a conventional softwood kraft pulp. Bleaching data from Basta and co-workers (1992 TAPPI Pulping Conference) are re-examined and re-interpreted in this study. We determined that ~60% to 65% of the overall ClO2 charge should be applied in the D0-stage. Peroxide addition to an (EOP) can replace 0.6 to 2.5 Kg. ClO2 per Kg H2O2. Boosting the (EO) temperature to 80°C is equivalent to a 70°C (EOP) with 0.25% to 0.30% H2O2,whereas a 90°C (EO) is equivalent to 0.50% – 0.75% H2O2 in a 70°C (EOP). The stoichiometric bleaching data from this study can guide decision-making for lowering chemical usage and minimize costs to reach target brightness levels with three- and five-stage sequences.

Pretreatment of Chlorine Dioxide Solution for Pulp Bleaching

2019 ◽  
Vol 13 (4) ◽  
pp. 523-531
Author(s):  
Shuangquan Yao ◽  
Baojie Liu ◽  
Shuangxi Nie ◽  
Shiwei Wang ◽  
Chengrong Qin ◽  
...  
Keyword(s):  
Chlorine Dioxide ◽  
Removal Rate ◽  
Surface Model ◽  
Chemical Additives ◽  
Pulp Bleaching ◽  
Solution Ph ◽  
Theoretical Support ◽  
Organic Halogen ◽  
Gas Removal ◽  
Chlorine Gas

Adsorbable organic halogen (AOX) is mainly produced by the reaction of residual lignin and chlorinated bleaching agents during bleaching processes. The formation of AOX can be reduced via optimization, addition of chemical additives, and/or pretreatment processes. Only a few studies exist on the effective purification of chlorine dioxide solutions and its effect on AOX reduction. In this paper, the effects of the extraction pressure, temperature, pH, and extraction time on the chlorine gas removal rate (CR) were evaluated. In addition, a response surface model was established to optimize the chlorine gas removal. The temperature of chlorine gas separation was optimized at 39.85 °C, with a separation pressure of –51.20 kPa and solution pH of 1.94, providing an estimated CR of 70.93% under the optimum separation conditions. Chlorine dioxide solutions with and without chlorine gas removal were used for pulp bleaching. AOX formation was reduced by 69.57% at the same 2.0% chlorine dioxide dosage, while the pulp brightness decreased by 3.0%ISO. In addition, AOX formation was reduced by 27.90% at the same bleached pulp brightness (80.00%ISO). The results provide theoretical support for the production of high-purity chlorine dioxide solutions and the development of clean pulping and papermaking processes.

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

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