Pulping Process Research Articles

Production of kraft pulp from Ochroma pyramidale wood

ABSTRACT Brazil stands out in the international scenario in the production of short-fiber pulp. Despite the great Brazilian biodiversity, that production is based on exotic Eucalyptus clones. In this sense, there may be great potential in the assessment of new sources of fibers from the Brazilian flora, including the Amazon. The present study aimed to assess the technical potential of the wood of Ochroma pyramidale (Malvaceae) for the production of kraft pulp. Four-year-old trees were harvested from a commercial forest for lumber production in Mato Grosso state (Brazil). We determined the wood’s chemical compositions (holocellulose, Klason lignin, soluble lignin, extractives and ash contents), physical properties (density and porosity), and fiber morphology (fiber length, width and thickness, lumen diameter, wall fraction, coefficient of flexibility, and slenderness and Runkel ratios). The wood was subjected to pulping with an effective alkali charge ranging from 10 to 24%, with intervals of 2%. Ochroma pyramidale wood presented characteristics favorable to the production of cellulosic pulp, such as appropriate fiber dimensions and low lignin, extractives, and ash content. The amount of residual active alkali and pH of the black liquor were positively related to the increase of the alkali charge employed in the pulping process. The increase of alkali charge decreased the pulp yield, kappa number and waste content, and increased the hexenuronic acid concentration.

Enhanced gas-liquid mass transfer coefficient by bulk nanobubbles in water

Liquid-gas operation explores the widespread applications in multiple chemical processes industries. For an instance, the inclusion of fermentation, dissolved air flotation, paper and pulp processing, sludge decomposition, aeration, ozonation, etc. are majorly covered. Liquid-gas contacting devices are primarily employed to perform their mixing, and the conventional contacting devices envelopes the fine bubble diffusers, jet aerators, surface aerators, static mixers, ejectors, etc. The gas transfer into the liquid is done by bubble formation, and the bubbles furthermore diffuses into the bulk liquid. The bubble size plays an important role in the transfer of gas, lower the size of bubbles, more is the rate of gas transfer, such as the mass transfer coefficient is remarkably enhanced by microbubbles when compared with milli-bubbles. In this work, we created O2 nanobubbles by sparging oxygen gas into nanopores, and during the production of nanobubbles, we examined the oxygen gas volumetric mass transfer coefficient (kLa) into the water. Nanoparticle tracking analysis was used to determine the population and size of nanobubbles, and we found that the population of nanobubbles is in the order of 107 bubbles/mL, with a mean diameter of 100–200 nm. The gassing out technique determines the volumetric mass transfer coefficient (kLa), and the influence of gas flow rate on the volumetric mass transfer coefficient (kLa) has been demonstrated to be positive. The volumetric mass transfer coefficient (kLa) in the case of nanobubbles is found significantly larger than that of microbubbles, ranging from 2.2 to 3.8 min−1.

Homogeneous microwave-assisted carboxymethylation from totally chlorine free bleached olive tree pruning residues pulp

This study deals with a new methodology for the production of carboxymethyl cellulose (CMC) from olive pruning residues, agricultural by-products. Cellulose was extracted by the soda?anthraquinone pulping process, and the pulp bleaching was performed using totally chlorine free (TCF) bleaching. Then, CMC microwave-assisted synthesis was performed in a homogeneous media, using DMA/LiCl as a cellulose solvent. A Box?Behnken design was applied in order to evaluate which parameters of the carboxymethylation process (viz. reaction time, reaction temperature, and amount of monochloroacetic acid) affect the degree of substitution and the yield of the synthesis reaction of this cellulose derivative. Optimized conditions to yield CMC were determined based on the desirability function approach. The prepared materials under synthesis using the optimal conditions were characterized using several analytical tools, i.e., FTIR, TGA, DSC and SEM. This cellulose derivative was successfully fabricated by a fast and efficient microwave-assisted method and thus would provide many opportunities for diverse applications.

Improvement of Ohmic Pasteurization in Mango Pulp Through CFD and RSM

Ohmic heating, also known as electrical resistance heating, is a novel process of pasteurization that has several advantages, including homogeneous heating, low heating time, high inactivation of microorganisms, and organoleptic and nutritional properties. Furthermore, mathematical tools allow for quick and low-cost analysis of behaviors with various operating parameters. This study aimed to improve the ohmic pasteurization process of mango pulp using computational fluid dynamics (CFD) and response surface methodology (RSM) using the experimental properties of mango pulp. The generated mathematical model is an accurate tool for predicting ohmic pasteurization behavior in an industrial environment; it presents a 4.4% standard deviation error in the experimental data. Furthermore, the arrangement and intensity of the added voltage analysis suggested operating variables with better pasteurization performance. Another observation was that the production speed was related to the voltage intensities of the inlet speed in a non-proportional manner. In addition, operation at a low inlet velocity may be more susceptible to thermal damage, whereas a high inlet velocity requires a particular proportion of voltage insertion to ensure adequate heat distribution.

Advanced Process Control Modeling from an Advanced Planning and Scheduling Perspective

Further to basic process control strategies, advanced process control (APC) aims to improve the performance of the control by actuating towards input moves against effects of process disturbances. Typically addressing economic-based goals as objectives, APC includes a wide range of techniques embedded in process control systems generally found in continuous-process industries such as processing of food, fuels, bulk chemicals, metals, minerals, pulp and paper, among others. Different from the well-known APC techniques such as feedforward, decoupling, inferential, constraint control, etc., we address a novel approach to the dependent-independent or controlled-manipulated pairing of variables of the model predictive control (MPC), also known as moving horizon control (MHC). We introduce manipulated variables as batch-processes into the MPC formulation to build the dynamic model with their paired controlled variables. The manipulated-controlled MPC formulation is configured as an advanced planning and scheduling (APS) problem as opposed to a traditional APC problem whereby the manipulated-batch-process variables are considered with relative-time yields representing their finite impulse-responses or differenced step-responses. As we shall show, APC problems can be equally formulated as a batch-process in APS perspective. To eliminate the steady-state offset between the actual controlled value and its target or setpoint, it is well-known to apply bias-updating though other forms of parameter-feedback are possible. Typically, APS applications only employ variable-feedback, i.e., opening or starting inventories, properties, etc., but this alone will not alleviate the steady-state offset. A small and representative example highlights the APC as an APS modeling with parameter feedback.

Crosslinked starch-coated cellulosic papers as alternative food-packaging materials.

In general, during the papermaking process or the production of cellulosic materials for food-packaging applications, lignin and other amorphous components are usually removed via the pulping and multilevel bleaching process to entirely separate them from the fiber. The aim of this work was to study the positive effect that can impart the residual lignin remaining in the alkali-treated fiber surface over bleached fibers to produce an alternative food-packaging cellulosic paper. Herein, cellulosic papers based on alkali-treated and bleached fibers obtained from the Alfa plant were successfully prepared using a compression process. The as-obtained papers were coated by crosslinked starch using a solvent-casting method to improve their mechanical and surface properties. The morphological and contact angle results showed that the residual lignin in the alkali-treated cellulosic papers strongly increased the interfacial adhesion by making the structure denser and more compact, resulting in an improved water resistance property over the bleached ones. On the other hand, it also promoted char formation, slowing down the burning process, resulting in better flame resistance. Additionally, the mechanical properties demonstrated that the presence of lignin contributed to the material rigidity improvement without compromising its flexibility (folding endurance). The as-developed cellulosic papers coated with crosslinked starch could be used for the production of high-quality materials for food-packaging applications using conventional industrial processes.

Bioactive, technological-functional potential and morphological structures of passion fruit albedo (Passiflora edulis)

Agroindustrial disposal generates tons of passion fruit albedo during pulp and juice processing. The reduction of this environmental pollution potential and its use involves research such as this one, which aims to determine the bioactive compounds in the passion fruit albedo (Passiflora edulis), its technological, functional potential and its morphological structures, aiming at food application. The methodologies applied followed internationally accepted and recommended guidelines. The results showed that the albedo flour obtained a yield of 9.76%, and from this, a semifine powder flour was prepared (75.8%), with 4.95% moisture, 40.72% reducing sugars, water activity of 0.37, pH of 5.29, total titratable acidity of 0.99 and total soluble solids of 1.5 °Brix. In addition, the presence of bioactive compounds such as polyphenols (18.88 mg AGE/100 g), flavonoids (13.51 mg/100 g), anthocyanins (1.74 mg/100 g) and chlorophyll b (69.65 mg/100 g) was evidenced, highlighting a considerable amount of vitamin C (377.36 mg/100 g) and pectin concentration (40.5%). In addition, the presence of bioactive compounds such as polyphenols (18.88 mg AGE/100 g), flavonoids (13.51 mg/100 g), anthocyanins (1.74 mg/100 g) and chlorophyll b (69.65 mg/100 g) was evidenced, highlighting a considerable amount of vitamin C (377.36 mg/100 g) and pectin concentration (40.5%).

Co-pyrolysis based activated Bio-char: Characterization and its utilization for secondary treated pulp and paper industry wastewater

In this study, the solid residue (bio-char) produced from co-pyrolysis of municipal sewage sludge (MSS)-sugarcane bagasse (SCB) was activated through a chemical activation method using phosphoric acid. The resulting activated bio-char was utilized for the removal of chemical oxygen demand (COD) and colour of pulp and paper industry wastewater obtained from conventional secondary treatment process to explore the recycling potential in the pulp and paper manufacturing process itself. In contrast to bio-char, activated bio-char showed higher surface area (50 times), total pore volume (10 times) and lower average diameter (5 times). Honeycomb shape in SEM image and existence of functional groups in FTIR spectra attributed to such a significant improvement. Results of adsorption experiments revealed that COD and colour was reduced by 84.61% and 98.03%, respectively at an optimized 3 pH with activated bio-char doses of 0.14 g/L in 20 h. Moreover, Langmuir and Freundlich isotherm model was observed best suited to obtained equilibrium.

Impact of controlled fermentation on the volatile aroma of roasted cocoa

Abstract The study of controlled methods of cocoa fermentation on a small scale is important to assess the maintenance of heat generated in the last days of fermentation. The research aimed to study the impact of spontaneous fermentation in controlled fermentation systems on the quality and acceptability of fermented cocoa beans. A 2×3 complete factorial design used different controlled fermentation systems (jacket system, solar heater and wooden box) and pulp reduction as variables. Samples were analyzed for fermentation index and volatile aroma composition profile using Headspace-Solid Phase Microextraction (HS-SPME) and Gas Chromatography-Mass Spectrometry (GC-MS). The profile of volatile compounds is evaluated for the studied variables using a multivariate Principal Components Analysis (PCA). The results showed increasing fermentation times in the jacket system seeing that it raised the fermentation rate and accelerated it to five days of fermentation combined with pulp reduction. The PCA analysis showed differences in the chemical composition of volatile compounds that were mainly associated with the reduction of the pulping process than the type of controlled system in four days of fermentation.

Methylation with Dimethyl Carbonate/Dimethyl Sulfide Mixtures: An Integrated Process without Addition of Acid/Base and Formation of Residual Salts.

Dimethyl sulfide, a major byproduct of the Kraft pulping process, was used as an inexpensive and sustainable catalyst/co-reagent (methyl donor) for various methylations with dimethyl carbonate (as both reagent and solvent), which afforded excellent yields of O-methylated phenols and benzoic acids, and mono-C-methylated arylacetonitriles. Furthermore, these products could be isolated using a remarkably straightforward workup and purification procedure, realized by dimethyl sulfide's neutral and distillable nature and the absence of residual salts. The likely mechanisms of these methylations were elucidated using experimental and theoretical methods, which revealed that the key step involves the generation of a highly reactive trimethylsulfonium methylcarbonate intermediate. The phenol methylation process represents a rare example of a Williamson-type reaction that occurs without the addition of a Brønsted base.

Development of a mathematical regression model of the beet pulp pressing process carried out on a deep press extruder

The article is devoted to the development of a mathematical regression model of the beet pulp pressing process carried out on on a deep press extruder. The following parameters of beet pulp pressing were taken as initial ones: initial moisture content (before the extruder) and final moisture content (after the extruder); sugar content in the pulp before and after pressing; sugar content in the pulp; beet chips length before and after pressing; total biological contamination of sugar beet pulp; pulp acidity before and after pressing; acidity of the granulated pulp. The Fuzzy Logic Toolbox module included in the MatLab package is used to implement the proposed technique. The Surfase Viewer module is used to present the simulation results in a graphical form. Such studies were previously carried out with the CurveExpert 1.3 application package. The resulting equations adequately describe the change in the sugar content in the pulp and its nutritional value depending on the pulp acidity and moisture content, as well as the length of the sugar beet chips. The significance of the influence of each of the main technological parameters (acidity and moisture content of the beet pulp, the length of the beet chips) on the amount of sugar in the pulp and its nutritional value was determined in the work. The resulting quadratic dependences having sufficiently high coefficients R2, adequately describe the process of beet pulp pressing in a deep press extruder with an assessment of the influence of variable parameters on the content of residual sugar and feed units in beet pulp. The data obtained make it possible to objectively evaluate the work of a deep-pressing exstruder and justify the kinematic mode of the screws rotation, which allows minimizing the cost of finished products.

Integration of dual fluidized bed steam gasification into the pulp and paper industry

The pulp and paper industry represents an industry sector which is characterised by its already high degree of sustainability. Biomass is a renewable input material, and typically highly developed recovery cycles minimise the loss of chemicals used in the pulping process. However, certain parts of the recovery cycle are still operated on fossil fuels. This study deals with the substitution of the fossil-based gaseous fuel with product gas from biomass gasification.Gasification experiments have shown that bark available at pulp and paper mills is suitable to produce a product gas via dual fluidised bed steam gasification as a promising substitute for natural gas. Based on the comparison of process layouts regarding the separation of non-process elements, separation efficiency is derived for different setups. To ensure operational security of the chemical recovery cycle, comprehensive gas cleaning including heat exchangers, a particle filter, and a liquid scrubber unit is advised. The gas flow of fuel gas into the gas burner is increased as the heating value of the product gas is accordingly lower in comparison to natural gas. Furthermore, adaptions of the gas burner might be necessary to address the earlier ignition of the H2-rich product gas compared to natural gas.

ROLE OF COMBINATION CASEIN AND LACTOFERRIN BOVINE’S COLLOSTRUM AS A PULP CAPPING ON MACROPHAGE EXPRESSION IN MALE WISTAR RATS

ABSTRACTBackground: Inflammatory and/or non-inflammatory processes play a role in stimulating pulp repair and the formation of hard tissue, namely reparative dentin. Macrophages play a role in the pathogenesis and chronic inflammatory disorders. The combination casein lactoferrin of bovine colostrum as an immunomodulator has therapeutic potential. This study aims to determine the therapeutic effect and duration of application of the combination of casein lactoferrin of bovine colostrum, on the expression of macrophages as pulp capping.Method: This study was a true experimental laboratories post test only control group design, consisting of three groups of 60 male wistar rats with 4 observation times, namely day to day 7, 14, 21 and 28 each of 5 mice. The maxillary 1st molars were prepared until the roof of the pulp was exposed. Three groups, namely the combination of casein and lactoferrin bovine colostrum (CKL) and calcium hydroxide (K1) and the untreated group (K0). Each group was filled with glassionomer as a permanent restoration. The tissue was made histological preparations with hematoxylin-eosin staining and the number of macrophages were counted, then analyzed by two way ANOVA and post hoc LSD tests.Result: The results showed that the therapeutic effect and duration of application of the combination of casein and lactoferrin bovine colostrum on the expression of macrophages as pulp cappingConclusion: The combination of casein and lactoferrin of bovine colostrum as capping material can increase the number of macrophages in the healing process of dental pulp.

A novel nitrogen-doped porous carbon derived from black liquor for efficient removal of Cr(VI) and tetracycline: Comparison with lignin porous carbon

The direct preparation of adsorption materials from black liquor (BL) produced by the kraft pulping process has great potential in wastewater treatment. A three-dimensional nitrogen-doped porous carbon (N-BLSAC) with high specific surface area and large pore volume was synthesized. The adsorption performance of N-BLSAC for Cr(VI) and tetracycline (TC) was systematically investigated. Compared with the porous carbon prepared from purified lignin (N-PLAC), the adsorption performance of N-BLSAC for TC was more superior. It was not only attributed to the pore-filling effect but also the electrostatic interaction, hydrogen bonding, and π-π electron-donor-receptor. In terms of Cr(VI), the adsorption performance of N-BLSAC and N-PLAC had little difference. Moreover, N-BLSAC and N-PLAC exhibited an excellent anti-interference property. Therefore, the porous carbon prepared by direct carbonization of BL has significant advantages in removing Cr(VI) and TC from aqueous solution.

Characterization of Birch Wood Residue after 2-Furaldehyde Obtaining, for Further Integration in Biorefinery Processing.

Latvia is a large manufacturer of plywood in Eastern Europe, with an annual production of 250,000 m3. In Latvia’s climatic conditions, birch (Betula pendula) is the main tree species that is mainly used for plywood production. A significant part of the processed wood makes up residues like veneer shorts, cores, and cut-offs (up to 30%), which have a high potential for value-added products. The aim of this research was to comprehensively characterize lignocellulosic (LC) biomass that was obtained after 2-furaldehyde production in terms of further valorization of this resource. The polymeric cellulose-enriched material can be used in the new biorefinery concept for the production of 2-furaldehyde, acetic acid, cellulose pulp, thermomechanical (TMP) and an alkaline peroxide mechanical (APMP) pulping process. In addition, we experimentally developed the best 2-furaldehyde production conditions to optimize the purity and usability of cellulose in the leftovers of the LC material. The best experimental results in terms of both 2-furaldehyde yield and the purity of residual lignocellulose were obtained if the catalyst concentration was 70%, the catalyst amount was 4 wt.%, the reaction temperature was 175 °C,and the treatment time was 60 min. After process optimization with DesignExpert11, we concluded that the best conditions for maximal glucose content (as cellulose fibers) was a catalyst concentration of 85%, a catalyst amount of 5 wt.%, a temperature of 164 °C, and a treatment time of 52 min.

Review on the Lymphatic Vessels in the Dental Pulp.

Simple SummaryIt is debatable whether lymphatic vessels exist in the dental pulp. Most researchers confirm their presence; however, the lymphatic system in the dental pulp is much less developed compared to other tissues of the body. Lymphangiogenesis occurs in the dental pulp with inflammatory changes as a response to inflammatory stimuli acting on the tooth. If lymphangiogenesis is defined as the development of lymphatic vessels from already existing ones, such a mechanism is possible only when lymphatic vessels are present in healthy teeth. Research papers have not conclusively proved whether lymphatic vessels can form in the dental pulp. The use of an immunohistochemical examination can very likely prove the presence of a lymphatic system in dental tissues. However, the evaluation of the lymphatic system of the teeth is problematic because it is quite difficult to clearly distinguish lymphatic vessels from small blood vessels.Despite many studies, opinions on the lymphatic system of the teeth are still incompatible. Studies using light and electron microscopy and directly using methods such as a radioisotope (radionuclide) scan and interstitial fluid pressure measurement reported incomplete results. Immunohistochemistry (IHC) plays the main role in investigating presence of the lymphatic system in dental tissues. This method uses labeled antibodies against antigens typical of lymphatic vessels. The use of appropriate staining enables the detection of antigen-antibody reaction products using a light (optical), electron or fluorescence microscope. However, these studies do not show the system of vessels, their histologic structure under physiological conditions and inflammation as well as the lymphangiogenesis process in the dental pulp. Unfortunately, there is a lack of studies associating the presence of lymphatic vessels in the dental pulp with local lymphatic nodes or large vessels outside the tooth. In the scientific and research environment, the evaluation of the lymphatic system of the teeth is problematic because it is quite difficult to clearly distinguish lymphatic vessels from small blood vessels. Despite many indications of the presence of lymphatic vessels in the pulp chamber, this problem remains open and needs further research.

Synthesis of Lignosulfonate-Based Dispersants for Application in Concrete Formulations.

Lignosulfonates (LS) are products from the sulfite pulping process that could be applied as renewable environmentally-friendly polymeric surfactants. Being widely used as plasticizers and water-reducing admixtures in concrete formulations LS compete in the market with petroleum-based superplasticizers, such as naphthalene sulfonate formaldehyde polycondensate (NSF) and copolymer polycarboxylate ethers (PCE). In this work, different chemical modification strategies were used to improve LS performance as dispersants for concrete formulations. One strategy consisted in increasing the molecular weight of LS through different approaches, such as laccase and polyoxometalate-mediated polymerization, glyoxalation, and reversible addition-fragmentation chain transfer (RAFT) polymerization. The other strategy consisted of preparing LS-based non-ionic polymeric dispersants using two different epoxidized oligomer derivatives of poly(ethylene glycol) (PEG) and poly(propylene glycol) (PPG). Modified LS were used to prepare cement pastes, which were examined for their fluidity. Results revealed that the most promising products are PPG-modified LS due to the introduction of PPG chains by reaction with phenolic moieties in LS. The enhanced dispersant efficiency of the ensuing products is probably related not only to electrostatic repulsion caused by the sulfonic ionizable groups in LS but also to steric hindrance phenomena due to the grafted bulky PPG chains.

Isolation of cellulose fibers from wetland reed grass through an integrated subcritical water hydrolysis-pulping-bleaching process

Cellulose fibers were isolated from wetland reed grass (Phragmites karka) by consolidated subcritical water hydrolysis, pulping and bleaching process. Phragmites biomass was treated with subcritical water at variable temperatures of 130–210 °C at constant pressure, reaction time and the biomass-to-water ratio of 3.5 MPa, 30 min and 1:50, respectively. The optimized temperature was found to be 170 °C with a total reducing sugars yield of 15.5 wt% and minimal charring of biomass. The treated biomass was carried out through pulping and bleaching process to isolate cellulose fibers. The highest cellulose yield was found to be 35.1 wt% with a residual lignin content of 0.4 wt% at 0.5 M NaOH. In a comparative study, the untreated biomass, subcritical water hydrolyzed biomass and cellulose were characterized by several physicochemical characterization tools such as proximate, ultimate and compositional analysis, thermogravimetric analysis, Fourier-transmission infrared, Fourier-transmission near-infrared and Raman spectroscopy, X-ray diffraction, solid-state nuclear magnetic resonance spectroscopy, scanning electron microscopy, transmission electron microscopy and atomic force microscopy to estimate the crystallinity index, carbon content, delignification, cellulose recovery as well as thermal stability and morphology of cellulose fibers. With the inclusion of subcritical water hydrolysis, a higher yield of cellulose was obtained from Phragmites with a crystallinity index of 65.3%. Due to the effective hydrolysis process, subsequent processes such as pulping and bleaching required less severe conditions.

Changes in Bioactive Compounds of Coffee Pulp through Fermentation-Based Biotransformation Using Lactobacillus plantarum TISTR 543 and Its Antioxidant Activities

The use of biotransformation has become a popular trend in the food and cosmetic industry. Lactic acid bacteria (LAB) are widely used due to their safety and beneficial effects on human health. Coffee pulp, a by-product obtained from coffee production, has antioxidant activity because it contains different classes of phenolic compounds. To investigate the factors affecting the biotransformation process of coffee pulp using L. plantarum TISTR 543, a systematic study using 23 factorial designs in a completely randomized design (CRD) was done. After the coffee pulp was bio-transformed, its bacterial count, pH, phenol contents, flavonoid contents, tannin contents, changes in bioactive compounds by LC-QQQ, and antioxidant properties were studied. The highest phenolic content was obtained in the sample containing the substrate, water, and sugar in the ratio of 3:10:3 with a 5% starter. After the fermentation was done, for 24–72 h, total bacteria count, total phenol contents, and antioxidant activities significantly increased compared to their initial values. Protocatechuic acid also markedly increased after 24 h of the biotransformation process. Hence, the fermentation of coffee pulp with L. plantarum TISTR 543 can produce substances with a higher biological activity which can be further studied and used as functional foods or active ingredients in cosmetic application.

Determination of Iron (Fe), Zinc (Zn) Levels and Organoleptic Tests in Coconut Pulp Flour

Coconut pulp is a by-product of coconut milk which contains high protein and good nutrition. This study aimed to determine the iron (Fe) and zinc (Zn) levels in coconut pulp flour using atomic absorption spectrophotometry and determine the characteristics of coconut pulp flour using organoleptic tests. The results showed that iron (Fe) level was 44.075 mg/kg and zinc (Zn) was 24.2 mg /kg. The organoleptic characteristics of the pulp were white and brownish for the dry powder, coconut-scented, a powder-shaped texture, and normal taste. The highest percentage level of hedonic scale for each criterion was 64% preferred for color, 52% preferred for aroma, 48% preferred for texture, and 52% preferred for taste. Based on these results, coconut pulp can be an alternative local food to meet iron and zinc needs for humans. The processing of coconut pulp as food can be used as a substitute flour in making bread, cakes, cookies, and other food preparations.