Optimasi Pengaruh Penambahan Hidrogen Peroksida Terhadap Kualitas Pulp Di EOP Stage

Penelitian dengan judul “Optimasi Pengaruh Penambahan Hidrogen Peroksida Terhadap Kualitas Pulp di EOP Stage” bertujuan untuk mengetahui dosis optimal yang memenuhi standar kualitas EOP Stage. Proses pemutihan di EOP (Ektraksi Oksidasi Peroksida) Stage merupakan proses pemutihan pulp dengan menggunakan bahan kimia yaitu H2O2. Parameter yang digunakan yaitu kappa number, viscosity, dan brightness. Pulp di bleaching menggunakan 5 variasi dosis yaitu 0,3 ml H2O2, 0,4 ml H2O2, 0,6 ml H2O2, 0,7 ml H2O2 dan 0,9 ml H2O2. Dari semua variasi dilakukan disimpulkan bahwa dosis yang optimal untuk menghasilkan kualitas pulp yang baik adalah 0,6 ml dan 0,7 ml dengan hasil nilai kappa number untuk 0,6 ml H2O2 adalah 1,3 dan 1,4 dan dosis 0,7 ml H2O2 adalah 1,14 dan 1,2. Lalu viscosity dari 0,6 ml H2O2 adalah 708 cm3/g dan 713 cm3/g sedangkan pada dosis 0,7 ml H2O2 adalah 703 cm3/g dan 707 cm3/g. Kemudian brightness dari 0,6 ml H2O2 adalah 79,62% dan 79,45% sedangkan pada dosis 0,7 ml H2O2 adalah 80,73% dan 80,12%.

Displacement washing of softwood pulp cooked to various levels of residual lignin content

This study investigates the influence of the degree of delignification of kraft spruce pulp cooked at seven different kappa numbers, ranging from 18.1 to 50.1, on the efficiency of displacement washing under laboratory conditions. Although the pulp bed is a polydispersive and heterogeneous system, the correlation dependence of the wash yield and bed efficiency on the Péclet number and the kappa number of the pulp showed that washing efficiency increased not only with an increasing Péclet number, but also with an increasing kappa number. The linear dependence between the mean residence time of the solute lignin in the bed and the space time, which reflects the residence time of the wash liquid in the pulp bed, was found for all levels of the kappa number. Washing also reduced the kappa number and the residual lignin content in the pulp fibers.

Assessment of Q(OP)D(PO) bleachability of softwood kraft pulp

Bleachability is evaluated as how easily a pulp sample is bleached and it depends on the structure of residual lignin and carbohydrates. Also, the bleachability varies depending on the bleaching sequence. ECF light sequences have been improved significantly in the recent years. However, we still don’t fully understand how ECF light bleach plants are optimally run. This work studies the bleachability of softwood kraft pulp in an ECF light bleaching sequence, (OO)Q(OP)D(PO). Three pulp samples with brown stock kappa number 27, 32 and 35 were bleached and studied for residual lignin, hexenuronic acid and carbohydrate content. It was found that in the bleaching stages that are highly delignifying, it is beneficial with a higher kappa number for the delignifying bleachability. However, in the bleaching stages where the objective is brightness increase, the brightness gain bleachability is improved by a lower kappa number. We also intended to determine which of the three samples had the best suited kappa number for this particular bleaching sequence. According to our results, the bleaching was most effective with kappa number around 32. Although an even higher kappa number resulted in higher yield after cooking, it seemed that this bleaching sequence cannot preserve the yield gain.

Technological evaluation of Pinus maximinoi wood for industrial use in kraft pulp production

This study characterized Pinus maximinoi wood and evaluated its performance for pulp production. Samples of Pinus taeda wood were used as reference material. For both species, wood chips from 14-year-old trees were used for the technological characterization, pulping, bleaching process analysis, and pulp properties. A modified kraft pulping process was carried out targeting kappa number 28±5% on brownstock pulp. The bleaching sequence was applied for bleached pulp with final brightness of 87±1 % ISO. Refinability and resistance properties were measured in the bleached pulps. Compared to P. taeda wood, P. maximinoi showed slightly higher basic density (0.399 g/cm³) and higher holocellulose (64.5%), lignin (31.1%), and extractives content (4.5%), along with lower ash content (0.16%). P. maximinoi tracheids showed greater wall thickness (6.4 µm) when compared to P. taeda tracheids. For the same kappa number, P. maximinoi and P. taeda resulted in similar screened yield, with an advantage observed for P. maximinoi, which resulted in lower specific wood consumption (5.281 m³/o.d. metric ton), and lower black liquor solids (1.613 metric tons/o.d. metric ton). After oxygen delignification, P. maximinoi pulp showed higher efficiency on kappa reduction (67.2%) and similar bleaching chemical demand as P. taeda pulp. Compared to P. taeda pulps, the refined P. maximinoi pulps had similar results and the bulk property was 10% higher. Results showed that P. maximinoi is an interesting alternative raw material for softwood pulp production in Brazil.

Bleaching of bagasse-pulp using short TCF and ECF sequence

More than 70 % bleached chemical pulp is produced in India through elemental chlorine-free bleaching in which chlorine-based compounds like chlorine dioxide is a dominant chemical which generates chlorinated organic toxins harmful to the environment. Present studies demonstrate short sequence of bleaching combined with acid treatment, followed by pressurized oxygen delignification. It was found that efficiency of oxygen improved by adding hydrogen peroxide as an additive in oxygen delignification with subsequent treatment with ozone or chlorine dioxide as bleaching agents. It was observed that by using additive in ODL process, pulp can achieve 70±1 (%ISO) brightness. Reduction attains in kappa number 65–70 % as compared to 45–50 % in control oxygen delignification stage. Through AOpZ and AOpD bleaching sequences, full brightness achieved 84–85 (%ISO) without considerable loss in mechanical strength properties compared to DEpD sequence. A potential reduction in COD, color, and AOX was 28, 53.3, and 88 % respectively were observed in AOpZ short bleaching sequence compared to DEpD bleaching.

Nitrate-Alkaline Pulp from Non-Wood Plants

Because there is a lack of wood resources in many countries, this work focused on pulp and paper production from the waste and agricultural residues of non-wood plants. The work aimed to pulp the nitrate-alkaline of black mustard (Brassica Nigra L.) and camelina (Camelina Sativa L.). The black mustard and the camelina were selected due to the expanding planted areas of these crops in the Czech Republic. To characterize the chemical composition of black mustard and camelina, cellulose, lignin, ash, and extractives were determined. Raw alpha-cellulose, beta-cellulose, and gamma-cellulose were also measured. The results showed that the content of lignin in non-wood plants is lower than that in softwoods. The cooked pulp was characterized by the delignification degree–Kappa number. Additionally, handsheet papers were made for selected samples of pulp. The handsheet papers were characterized by tensile index, breaking length, and smoothness and compared with commonly available papers.

Chemical and morphological characterization and pulping of Casuarina equisetifolia

Bangladesh is very much successful in coastal afforestation programmes, which protects from frequent cyclones. Casuarina equisetifolia has showed a climate resilient and promising species. No study has been done on industrial application of C. equisetifolia in Bangladesh. In this study, C. equisetifolia was characterized in terms of chemical, morphological and anatomical properties. It is characterized with higher α-cellulose, similar hemicelluloses and lignin as compared to other hardwood species grown in Bangladesh. The C. equisetifolia lignin contained mainly of syringyl unit followed by guaiacyl unit. The fiber of C. equisetifolia was shorter in length with very thick cell wall and narrow lumen, consequently the wood density and runkel ratio were very high (2.89). The C. equisetifolia was also fractionated by formic acid (FA) at atmospheric pressure to pulp, dissolved lignin and hemicelluloses. Pulp yield was 50 % with kappa number of 40 at the conditions of 3 h treatment with 90 % FA followed by 2 h peroxyformic acid treatment. But in the kraft process, C. equisetifolia produced pulp yield of 44 % with kappa number 17. Both pulps showed good bleachability. The papermaking properties were in acceptable range. Finally, it can be said that C. equisetifolia is promising species for pulping.

Xylanase pretreatment of mechanically destructured chips of Eucalyptus tereticornis and its effect on kraft pulping

Mechanical pulping of raw wood material is a highly energy intensive and pollution generating step in the papermaking process. This study focused on combined mechanical and xylanase treatment prior to the kraft pulping of E. tereticornis. A screened pulp yield of 49.1% (on oven-dry wood basis) with a Kappa number of 24.9 was obtained at the optimum cooking temperature of 160 °C without any pretreatment of the wood chips. After mechanical treatment (destructuring), a slightly higher screened pulp yield (49.4%) was obtained with a Kappa number of 24.2 at the cooking temperature of 145 °C with the same active alkali charge (15%). The optimum cooking temperature was further reduced to 140 °C for the destructured xylanase-treated wood chips. The xylanase treatment resulted in a 2% reduction in screened pulp yield due to hydrolysis of xylan. However, the Kappa number was reduced to 18.2 after xylanase pretreatment of the mechanically destructured wood chips. The combined pretreatment (destructured and xylanase treatment) of wood chips resulted in a reduction in cooking temperature by 20°C compared to untreated wood chips. Such a reduction in cooking temperature can effectively reduce steam consumption. The combined pretreatment improved the pulp brightness by 2.0 (ISO points) and physical strength properties, which included the tensile index, tear index, and burst index by 11.06%, 21.72%, and 21.79%, respectively, compared to the control.