Sulfate Pulp Research Articles

МОДЕЛИРОВАНИЕ ПРОЦЕССА СЖИГАНИЯ ЧЕРНОГО ЩЕЛОКА В ТОПКЕ СОДОРЕГЕНЕРАЦИОННОГО КОТЛА

A recovery boiler is used in pulp and paper production and is an important element of the chemical regeneration cycle of sulphate pulp production. It is designed to regenerate, i.e. restore the properties, of black liquor used up in the brewing process. The black liquor is regenerated by burning it in the furnace of the recovery boiler. It is a complex power engineering facility, as it combines a chemical reactor and a steam power boiler unit. In addition, the recovery boiler is highly explosive. In this connection, the automation of the processes in this power plant plays a special role. In this paper, a model related to the black liquor combustion stage in the furnace of a recovery boiler is developed based on data from pulp and paper mills.

The Construction of the Revolutionary Year of 1917: The First Russian Sulphate Pulp Plant

During the First World War in Russia, along with mobilization and evacuation, the construction of industrial enterprises was carried out. The study of this problem will allow us to understand how decisions were made on the construction of new production facilities in the deteriorating socio-economic situation, how the construction was carried out and how it depended on the course of the revolutionary process in the country. Using the example of the joint-stock company of the Nikolay-Pavdinsky mountain district, it is shown how the project of constructing the country’s first sulphate pulp plant was implemented in the Northern Urals. The development of the forest industry in the mountainous district began at the beginning of the 20th century, on the eve of the First World War, a paper mill was built near the Lyalya station, its expansion was planned for several years. The stimulating factor was also the growth of the needs of the population and industry for paper due to the loss of a number of western regions of the empire. The receipt by the joint-stock company of solid revenue in the 1915/1916 operating year allowed it to begin the practical implementation of the project, hoping to put the enterprise into operation in 1918. In the spring of 1917, the firm “A. V. Bolotnikov & Co” began its construction. It was revealed that sometimes conflict situations arose between the contractor and the management of the mountain district. A positive role in their solution was played by the experience of A. V. Bolotnikov and the actions of the district leaders. In autumn, most of the construction work was completed, but the change of government, the sharp deterioration of the transport and financial situation did not allow the company to be equipped.

Smarter ways to capture carbon dioxide – exploring alternatives for small to medium-scale carbon capture in Kraft pulp mills

Carbon capture from the calcination process in Kraft pulp mills, also known as sulphate pulp mills, has potential as a part of carbon capture and storage (CCS) infrastructure deployment. Growing concern of climate change is increasing the interest for so-called negative emission technologies (NETs), and large emission points have great potential. However, among other factors, lack of financial incentives, trade-off with investments in existing products, and the necessity of large infrastructure that stretch across country borders, constrain deployment. This study investigates two concepts for carbon capture in combination with lime kilns in Kraft pulp mills: oxyfuel combustion and electric arc plasma calcination. The results from the modelling of six configurations show that carbon capture from the calcination process with these technologies can be made with comparatively low additional energy demand. Sulphate pulp production from Kraft pulp mills, which use lime kilns, is increasing in Europe and in the world. Therefore, there is large potential for capture of CO2 from these alternative calcination technologies, both as a first step towards and as a part of a large-scale deployment of CCS and bioenergy with CCS (BECCS).

Enhanced energy savings in enzymatic refining of hardwood and softwood pulp

BackgroundPulp refining is an energy consuming, but integral part of paper production with the aim to increase tensile strength and smoothness of paper sheets. Commercial enzyme formulations are used to lower the energy requirements by pre-treatment of pulp before refining. However, a high number of different commercial enzyme products are available on the market containing enzymes of varying origin and composition, which complicates the prediction of their behavior, especially using different pulp types.ResultsEndoglucanase-rich enzyme formulations were characterized regarding enzyme activity at different temperatures, resulting in a significant decrease of activity above 70 °C. Some enzyme preparations additionally contained arabinosidase, xylanase and β-glucosidase activity consequently resulting in a release of xylose and glucose from pulp as determined by high-performance liquid chromatography. Interestingly, one enzyme formulation even showed lytic polysaccharide monooxygenase (LPMO) activity of 3.05 nkat mg−1. A correlation between enzyme activity using the endoglucanase specific derivatized cellopentaose (CellG5) substrate and enzyme performance in laboratory PFI (Papirindustriens forskningsinstitut) refining trials was observed on softwood pulp resulting in a maximum increase in the degree of refining values from 27.7°SR to 32.7°SR. When added to a purified endoglucanase enzyme (31.6°SR), synergistic effects were found for cellobiohydrolase II (34.7°SR) or β-glucosidase enzymes (35.7°SR) in laboratory refining. Comparison with previously obtained laboratory refining results on hardwood pulp allowed differences in enzyme performance based on varying pulp types to be elucidated.ConclusionsInterestingly, the individual enzymes indeed showed different refining effects on softwood and hardwood pulp. This difference could be predicted after development of an adapted enzyme activity assay by combination of the derivatized cellopentaose CellG5 substrate with either softwood or hardwood sulfate pulp.

Utilization of palm fiber as papermaking materials: Microscopic structure and chemical pulping

The microscopic structure and pulping properties of palm fiber were explored. Soda cooking and sulfate cooking were conducted and compared in terms of physical strength of the obtained pulps. Sulfate pulp showed better performance than soda pulp, as indicated by the 23% higher tensile index, 49% higher tear index, and 36% higher burst index. To further elevate physical strength, long fibered pulp (LFP), namely commercial softwood sulfate pulp, was mixed with sulfate pulp of palm fiber at levels from 20% to 50%. At the blend level of 50%, tensile index of 52.13 N•m/g, tear index of 15.63 mN•m2/g, and burst index of 3.42 kPa•m2/g were attained. The lignin in spent liquor from pulping was isolated and characterized. Soda lignin of palm fiber was mainly composed of guaiacyl and syringyl units, and showed weight-average molecular weight of 3616 g/mol.

Effect of nine-year soil contact on physical performance of crude tall oil impregnated, copper salt impregnated, and non-treated Scots pine posts

ABSTRACT Crude tall oil (CTO), a side product of sulphate pulping, has promising results in moisture and decay resistance. This article reports the Pilodyn indentation hardness, basic density, and mechanical performance of 600-mm long Scots pine posts after a nine-year soil contact test. The material consisted of round and square-shaped CTO-impregnated posts, supplemented by copper salt-impregnated and untreated reference posts. In total, 240 posts were installed in fertile soil in south-eastern Finland in spring 2010. Posts were harvested in May 2019. At the end of the test, 192 posts were in a condition that allowed the preparation of specimens for density and compression tests. Discs were sawn from the ground level, as well as above and below the ground level to measure the density and deformation under static 45,000 N parallel-to-the-grain compression load. Altogether 80% of the untreated control posts were rejected from further tests due to severe decay. Square-shaped control posts had a slightly higher survival rate than the round ones. After a nine-year soil contact, the performance of CTO impregnated. Scots pine posts were clearly better than that of untreated control posts and comparable to that of copper salt-impregnated posts. The study suggests that CTO has a high potential as a non-biocide wood preservative even in structures in soil contact.

Concept of PPI energy technology complex upgrading

THE PURPOSE. Development and implementation of a set of theoretical and practical recommendations for creating scientifically founded heat flow diagrams for pulp and paper processes, intensifying heat exchanging processes under the economical use of energy resources. METHODS. The method of thermodynamic analysis on the basis of exergy increments in the process of interaction of heat flows is proposed, it allows evaluating the energy efficiency of both individual PPI units and the entire process flow; mathematical relationship between exergy efficiency of process elements and that of a complex heat flow diagram; schematic diagram of a heat recuperator of PBM drying section with a closed loop for the air delivered to drying. RESULTS. Thermodynamic analysis was made to evaluate energy efficiency of PPI equipment; the relationship between conversion factor of thermal pumping plant and thermodynamic properties of actuating media was obtained. Sulfate pulp production was considered in detail. The low energy efficiency of the existing process flow diagram is shown, with its exergy efficiency being equal to 48%. A main share of the consumed exergy (71% of the incoming one) relates to the recovery boiler processes. The process flow diagram consisting of hydrochemical pulpchips processing is suggested. The recovery boiler and rotary-type lime kiln are removed from that flow diagram. Risks of air and water basins pollution fall. The main ways for increasing energy efficiency of lignosulfonates production at sulfite pulp plants are mentioned. DISCUSSION. Further development of energy efficient pulp technologies can be forecasted on the basis of application of fluid technologies such as supercritical water oxidation (SCWO). The positive results of research in water chemistry under supercritical parameters give promise to predict success in developing the energy efficient pulp technology by exposing pulpchips to water at the subcritical and supercritical parameters. Paper and board production relates to the complex physical–chemical and heat-wet processes. The thermodynamic studies allowed determining low exergy efficiency of a drying section of paper and board machine that is because of inefficient operation of the heat recuperation unit. This circumstance is responsible for the bulk supply of low pressure steam from a heat and power plant. The main ways for improving the heat flow diagram of PBM drying section are shown. Cogeneration issues in the pulp and paper industry are considered. The essential attention is given to environmental safety of energy efficient technologies. CONCLUSION. The paper presents main ways for increasing energy efficiency of basic production processes at pulp and paper enterprises. Based on the analysis of exergy efficiency of individual equipment elements and the entire process flow diagrams bottlenecks were revealed and measures for their removal were suggested.

Influence of the Scheme of Bleaching Hardwood Sulfate Pulp Using Chlorine Dioxide on Chlor-Organic Compounds in Wastewater and Cellulose

Study results of the effect of reducing the steps of the bleaching scheme hardwood sulfate pulp including oxygen-alkaline treatment (OAT) to obtain chlor-organic compounds in filtrates and cellulose. It was determined that a shortened bleaching scheme including oxygen-alkaline treatment would reduce chlorine dioxide consumption by 48 %, to achieve the requirements of best available technologies for the discharge of adsorbed organically bound chlorine in wastewater and the total organic chlorine content in deciduous bleached cellulose.

Furnishing autohydrolyzed poplar weakly alkaline P-RC APMP to make lightweight coated base paper

This work investigated the effects of autohydrolysis pretreatment severity on poplar (Populus tomentosa Carr.) woodchips used to make a type of high-yield pulp (HYP) known as preconditioning followed by refiner chemical treatment, alkaline peroxide mechanical pulp (P-RC APMP). It also investigated the ratios for partial-ly replacing sodium hydroxide (NaOH) with magnesium oxide (MgO) in the high-consistency (HC) retention stage of the P-RC APMP process on the obtained HYP’s properties. The results show that the pretreatment severity of autohydrolysis at combined hydrolysis factor (CHF) = 10.77 and the 50 wt% ratio for partially substituting NaOH with MgO were the optimum conditions for making light-weight coated (LWC) base paper. Compared to the conventional P-RC APMP, the optimized P-RC APMP had similar bulk and higher tensile, burst, and tear indices, as well as opacity, but a slightly lower ISO brightness. When the optimized P-RC APMP and commercial softwood bleached sulfate pulp (SBKP) were blended to make LWC base paper, the most favorable pulp furnish was comprised of 50% optimized P-RC APMP and 50% commercial SBKP. The obtained LWC base paper handsheet had better bulk, and its other properties could also meet the require-ments of LWC base paper.

Surface modification of cellulose originated from different plant sources through TEMPO/Laccase/O2 oxidation

An environmentally friendly 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO)-mediated oxidation system using halogen-free reagents has attracted much attention. At present, cellulose nanofibers (CNFs) with a high carboxyl content can be prepared by TEMPO/laccase/O2 (TLO)- oxidation of hardwood bleached kraft pulp (HBKP) under aqueous conditions, while, the related research is still in its infancy. For example, the further applications of TLO-CNFs and the oxidation effect of the TLO system on cellulose from different sources have not been studied. In this work, cellulose from four different sources, that is, HBKP, softwood bleached kraft pulp (SBKP), bleached bagasse sulfate pulp (BBSP) and microcrystalline cellulose (MCC), was oxidized by using a TLO-oxidation system. All cellulose materials were found to be able to be oxidized successfully regardless of the source, which proved the universality of the TLO-oxidation system. Different from traditional TEMPO/NaBr/NaClO (TBN)-oxidation that introduces major carboxyl groups (0.846–1.154 mmol/g) and minor aldehyde groups (0.041–0.097 mmol/g) to cellulose, carboxyl (0.558–0.615 mmol/g) and aldehyde (0.218–0.235 mmol/g) groups can both be sufficiently introduced on the surface of TLO-oxidized cellulose. Based on the aldehyde groups introduced, the wet strength of the TLO-oxidized cellulose handsheet was greatly improved to 400% of the non-oxidized one due to the formation of hemiacetal linkages. In addition, oxidized cellulose can be isolated to homogeneous TLO-CNFs or TLO-cellulose nanocrystals (CNCs), and TLO-CNFs (CNCs) can easily be processed into films and hydrogels with high light transmittance and excellent mechanical properties. Remarkably, compared to the other TLO-CNFs, TLO-CNFs (BBSP) has higher aspect ratio with thinner width (nanofibers as thin as 2 nm can be achieved). Thus, the mechanical properties of TLO-CNFs (BBSP) assembled films and hydrogels were superior to others. These all providing significance and promising prospects for the applications of TLO-oxidation systems, meantime, the distinctive characteristics of TLO-CNFs (BBSP) were explored.

РЕСУРСОЗБЕРІГАЮЧА ТЕХНОЛОГІЯ ОДЕРЖАННЯ КАРТОННО-ПАПЕРОВОЇ ПРОДУКЦІЇ

Nowadays, the products of domestic enterprises of the pulp and paper industry are 80% made from secondary raw materials – recycling paper, which negatively affects its quality, narrows the range and limits the scope of use. This state of the industry connected with the lack of domestic production of cellulose fibrous products. The raw material problem of the pulp and paper industry of Ukraine can be solved by using annual plants and wastes of crop processing for the production of fibrous materials for various purposes. Rapeseed stalks can be considered as a promising raw material to meet the needs of the pulp and paper industry. The aim of the work is to study the physical and mechanical properties of writing paper and cardboard for flat layers of corrugated cardboard, which contain cellulose fibers of rapeseed stalks. This paper presents the results of research of sizes of elementary cellulose fibers from rapeseed stalks. Studies of the fractional composition showed that 70% of cellulose fibers from rapeseed have a length in the range of 0.02 to 0.81 mm and only 30% have a length exceeding 1 mm. To study the effect of cellulose content from rapeseed stalks in the composition of writing paper, paper samples of 80 g/m2 were prepared at different ratios of cellulose from non-wood raw materials to coniferous cellulose. Studies have shown that the surface of paper made of non-wood pulp has a high smoothness and uniform lumen and is more elastic compared to paper made of bleached coniferous sulfate pulp. According to the results of physical and mechanical tests, it can be concluded that the increase in the content of non-wood pulp from rapeseed stalks in the composition of writing paper leads to a decrease in all physical and mechanical properties of the paper. To study the effect of non-wood pulp from rapeseed stalks in a cardboard composition for flat layers of corrugated cardboard, cardboard samples of 175 g/m2 were made. Recycling paper of MS-6B was used as a bottom layer, and non-wood pulp as a surface layer of cardboard. The ratio of recycling paper to non-wood pulp in laboratory samples of cardboard was 80:20 mass %. According to the results, it can be concluded that the use for the surface layer of non-wood pulp from rapeseed stalks allows to obtain cardboard with strength values that fully meet the requirements for cardboard of K-1 type. In general, it was shown that non-wood rapeseed pulp can be used to replace more expensive sulfate bleached coniferous pulp in the production of writing paper and cardboard for flat layers of corrugated cardboard as a surface layer.

Biorefining: the role of endoglucanases in refining of cellulose fibers

With an annual production of more than 400 million tons, paper is the main product of the largest biorefinery process industrially implemented. Enzymes have been used for pulp refining to dramatically reduce energy consumption. However, exact mechanisms related to the individual enzymes are hardly understood. Yet, this knowledge would be important to predict enzyme performance in industrial processes. Three commercial refining enzyme formulations showed different endoglucanase (1.25 nkat mg−1–13.7 nkat mg−1), β-glucosidase (0.57 nkat mg−1–1.34 nkat mg−1) and xylanase activities (1.78 nkat ml−1–62.1 nkat mg−1) on model substrates. Additionally, distinct amounts of reducing sugars from hardwood sulfate pulp were released. Endoglucases were purified from each formulation by using hydrophobic interaction and anion exchange chromatography and showed molecular weights from 20 to 55 kDa and specific activities ranging between 3.11 and 26.3 nkat mg−1 according to endoglucanase specific derivatized cellopentaose (CellG5). Refining trials of hardwood sulfate pulp were conducted using a PFI laboratory mill and fiber properties such as degree of refining or fiber length and properties of formed sheets like tensile index were monitored. Thereby, enzymes were dosed based on identical endoglucanase activity on CellG5. Enzyme formulations and purified endoglucanases led to an increase of the degree of refining of up to 47.9 [°SR] at 6000 PFI revolutions while the tensile index was improved by up to 76.0 Nm g−1. In summary, refining effects can be primarily attributed to endoglucanases indicating activity on CellG5 being a suitable parameter for enzyme dosing.

Study in fatty acids of tall oils and their products of esterification by the method of IR spectrometry for analytical control of preparation of esters

Tall oil fatty acids are a by-product of the sulfate pulping of cellulose. The field of application of tall oil fatty acids is currently limited to the production of polyhydric alcohol esters (glycerol, etriol, and pentaerythritol, primarily, for the production of alkyds); ethanolamides; disproportionated and dimer acids (including amides based on them); imidazolines; salts; as well as lower alkyl esters. However, tall oil fatty acids have the potential to be used as a basis for the synthesis of motor oils and their additives, additives to diesel fuel, as well as raw materials for the production of biodiesel fuel.

Residual Birch Wood Lignocellulose after 2-Furaldehyde Production as a Potential Feedstock for Obtaining Fiber.

From birch wood, it is possible to obtain both acetic acid and 2-furaldehyde as valuable value-added products. The main objective of this study was to develop a new wasteless technology for obtaining 2-furaldehyde, acetic acid, and lignocellulose (LC) residue usable as feedstock in further processing such as thermomechanical (TMP), alkaline peroxide mechanical (APMP), and sulfate pulping processes. To achieve this objective several screening tests were performed, and a further experimental plan was developed using DesignExpert11. Process yields were analyzed both in terms of total yield and at individual time increments. In addition, the obtained LC residue was also characterized. A unique bench-scale reactor system was used to obtain an LC material without pentoses and with maximum preservation of cellulose fiber for further research. Studies on the deacetylation and dehydration of birch wood hemicelluloses of pentose monosaccharides to 2-furaldehyde and acetic acid using orthophosphoric acid as a catalyst were carried out. Results showed that, depending on the used pre-treatment conditions, the 2-furaldehyde yield was from 0.04% to 10.84% oven dry mass (o.d.m.), the acetic acid yield was from 0.51% to 6.50% o.d.m., and the LC residue yield was from 68.13% to 98.07% o.d.m. with minimal content of admixtures. Process optimization using DesignExpert11 revealed that the main pre-treatment process parameters that influenced the yield of 2-furaldehyde in the pre-treatment process were process temperature (53.3%) and process duration (29.8%).

Минимизация содержания хлора в беленой сульфатной целлюлозе для санитарно-гигиенических изделий и упаковки пищевых продуктов

The increasing consumption of pulp for chemical processing, including production of sanitary tissue products and other medical products, food packaging, as well as fillers for food products leads to new requirements for the quality of raw materials. The task of improving the characteristics of pulp has become particularly acute in connection with the COVID-19 epidemic: the demand for disposable nonwoven materials in direct contact with the human skin has increased several times over. The elemental chlorine free (ECF) sulfate pulp bleaching process, which uses chlorine dioxide as a bleaching agent, dominates bleached pulp production worldwide. The chlorine-containing compounds formed as a result of bleaching pollute not only waste water, but also the product itself. In the near future, it is expected that paper products made with chlorine-based bleaches may be banned for the production of sanitary tissue products and food packaging. If the products of the pulp and paper industry do not meet international consumer requirements, the pulp market for these purposes may face undesirable results. The most promising direction of modernization the existing bleaching schemes, both in terms of the process consumption parameters and the quality of the produced pulp, is the use of oxygen-alkaline bleaching in the first stage. Determination of total and organically bound chlorine content in pulp materials in accordance with ISO 11480:2017 on the advanced plant has shown, that the introduction of bleaching schemes using oxygen-alkaline agents will ensure the recommended content of chlorine compounds while maintaining the necessary characteristics of pulp for the manufacture of medical and sanitary tissue products, food packaging. However, high quality of finished products that meet consumers’ requirements is possible only if the chlorine content is controlled at all stages of pulp production, since the quantitative indicators of this substance content remain close to the upper allowable limit. For citation: sofronova e.D., Lipin v.A., Dubovy v.K., Sustavova t.A. Minimizing the Chlorine Content in bleached sulfate pulp for sanitary tissue products and food packaging. Lesnoy Zhurnal [Russian Forestry Journal], 2021, no. 3, pp. 186–195. DOI: 10.37482/0536-1036-2021-3-186-195

Potential Use of Oil Palm Fronds for Papermaking and Application as Molded Pulp Trays for Fresh Product under Simulated Cold Chain Logistics

ABSTRACT Waste paper from newsprint, a key feedstock for molded pulp trays, is globally deficient due to digital shifts. Hence, the alternative fiber source needs to be explored. The potential use of fiber from oil palm fronds for protective packaging under humid conditions was studied. Fibers were isolated from petioles by sulfate pulping with 30.72% yield. The high α-cellulose content (38%) showed valuable for papermaking. Runkle’s ratio (0.63), rigidity coefficient (38.46), and slenderness value (100) suggested that the paper would have excellent mechanical properties. Under cold chain logistics, packaging must withstand high humidity and low temperature (90%RH, 12°C). Addition of 1.4% cationic starch and 0.5% AKD significantly enhanced water absorption resistance from 59 to 23250 sec and improved the burst (6.68%) and tensile index (26.47%). The molded pulp trays fabricated from 70% sized frond fibers and 30% OCC fiber provided 7.71% higher compressive strength than neat OCC tray. All physical properties indicated that the as-prepared trays have potential use for protective material. A simulation with green apple demonstrated that the trays were impractical for use with soft-skinned fruit as the dense and rough surface of the packaging. Further study to evaluate cushioning performance for harder skin fruit is, therefore, necessary.

Определение математической зависимости плотности черного щелока от содержания сухих веществ (хвойная ЦВВ)

A modern evaporator station is an energy-saving production of evaporated liquor with high dry matter content for ensuring the minimum SO2 emissions from the soda recovery boiler. Such stations are equipped with Falling Film devices and consist of 5–7 stages. The necessity to improve and create new black liquor concentrators is driven by the increased attention to environmental issues and the wish to produce liquor with a higher calorific value. The physical properties of black liquor depend on its composition and have a significant impact on the selection and design of evaporators. The main properties considered in the evaporation and combustion processes are density, viscosity, surface tension, heating value and boiling temperature. One of the most important characteristics of the liquor evaporation is its viscosity, since it determines the ability of the liquor to pump and affects the design features. Another equally important characteristic is density. With its help, the dry matter content and evaporation process in the main stages of the liquor regeneration are regulated. The study was carried out to determine the mathematical dependence of the black liquor density on the dry matter content for high yield softwood pulp. The study objectives were the following: analyze the effect of the dry matter temperature and concentration on the density of black liquor obtained from cooking high yield softwood pulp according to the technological flow of production; develop a mathematical model of dependence of the black liquor density of high yield sulphate softwood pulp on the concentration and temperature; conduct the TAPPI comparative testing of the results of mathematical and correlation dependences. A mathematical dependence of the black liquor density on the temperature and dry matter content required for immediate technological calculations of chemical regeneration departments in sulphate production of semi-finished products for cardboard was obtained. The following equation of mathematical dependence based on the conducted research, regression analysis, and mathematical processing of the results was obtained: ρ = 0.974 + 0.0071x – 0.0002t – 0.000007xt – 0.00000045t2 – 0.0000045x2 (where ρ – density, g/cm3; x – dry matter content, %; t – temperature, °C). It allows calculating with the highest accuracy the density of black liquor obtained from cooking high yield softwood sulphate pulp. Comparative testing of the results of the developed mathematical dependence and correlation dependence (published by TAPPI) of black liquor density on the dry matter content was carried out. A high level of comparability of the proposed mathematical equations was found.

The component composition of planted pine wood cultivated in the boreal zone

Abstract The present study analyzes the composition of pine wood cultivated on artificial plantations in the Leningrad Oblast (Region). Comparing to pine wood from natural stands, a smaller heartwood zone along the height of the pine trunk and a lower content of resinous substances are noted. The content of cellulose and lignin in the heartwood and sapwood of pine is distributed differently along the trunk. The distribution of pentosans and water-soluble substances in the heartwood and sapwood along the trunk is associated with the lignin complex. The component composition of the studied pine wood from planted stands is quite uniform in its indicators if compared to the wood of older natural stands. Sulphate pulping of planted pine wood showed a higher yield of technical cellulose than the average yield from wood obtained at natural stands of the studied region.

Optimization of Banana Stem Pulp to Substitute SoftWood Pulp for High Quality Paper

Abstract This study deals with optimizing pulping conditions of the banana stem to substitute softwood pulp in writing and printing paper. Scanning micrograph and chemical composition of banana stem indicate that banana fibers are flat, flexible, long (2.24 mm) and the raw banana is characterized with high cellulose (65%) and low lignin (13.5%)contents. The banana stem was pulped using Kraft process (8.5 % alkali as Na2O and 17% sulfidity cooked at 105oC for 3 hr. Detail mechanism of the pulping parameters was discussed. The obtained pulps were characterized with respect to yield (64%) and Kappa number (35%). Compared to imported softwood pulp, all strength properties and opacity are high. This is attributed to the long banana fibers and the high cellulose content. The effect of these two parameters on tensile, burst, and tear, strengths was discussed. High quality of writing and printing paper was obtained by a furnish blend ratio of 20%-80%, banana stem pulp, and commercial bagasse pulp respectively. Keywords: Banana Stem, Fiber length, Sulfate pulp, writing and printing papers.

Применение окислительного щелочения в процессе отбелки лиственной сульфатной целлюлозы

Pulp and paper plants use chlorine dioxide, oxygen, and hydrogen peroxide for pulp bleaching. The paper aims at analyzing the effect of oxidative alkali treatment with the addition of oxygen and hydrogen peroxide on hardwood sulphate pulp bleaching using ECF technology. The results of an experiment in assessing the performance of oxygen and hydrogen peroxide in alkali treatment are presented in relation to the conditions prevailing at the Russian plants. The scheme of hardwood pulp bleaching was as follows: D0–E (EO, EP, EOP)–D1–D2; where D – chlorine dioxide treatment, E – alkali treatment (with oxygen, with hydrogen peroxide, and with oxygen and hydrogen peroxide). Evaluation of the experimental findings allows to conclude that the oxygen utilization at the alkali stage is insufficient in pulp bleaching under a pressure of 0.2 MPa. The maximum reduction in the amount of kappa sulfate pulp and a decrease in the consumption of chlorine dioxide at the final bleaching is provided by oxidative alkaline treatment with the addition of hydrogen peroxide with a flow rate of 3.0 kg/t. For the D0–EOP–D1–D2 scheme, the addition of 1.0 kg/t of hydrogen peroxide reduces the consumption of chlorine dioxide at the stages of the final bleaching of pulp to 2.7 kg/t.For citation: Koroleva T.A., Milovidova L.A., Komarova G.V., Dryakhlitsyn A.A., Medvedev V.V., Moseev V.G. The Use of Oxidative Alkali Treatment for Sulphate Hardwood Pulp Bleaching. Lesnoy Zhurnal [Russian Forestry Journal], 2020, no. 4, pp. 168–177. DOI: 10.37482/0536-1036-2020-4-168-177Funding: The equipment of the Innovative Facilities Engineering and Innovation Center “Advanced Northern Bioresources Processing Technologies (Northern (Arctic) Federal University named after M.V. Lomonosov) was used during the research. The center was founded with the financial support from the Ministry of Science and Higher Education of the Russian Federation.