Academic literature on the topic 'Sulfate pulping process Mathematical models'
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Journal articles on the topic "Sulfate pulping process Mathematical models"
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Hernández-Hernández, Hilda M., Jorge J. Chanona-Pérez, Alberto Vega, Pablo Ligero, Reynold R. Farrera-Rebollo, Jorge A. Mendoza-Pérez, Georgina Calderón-Domínguez, and Norma Güemes Vera. "Spectroscopic and Microscopic Study of Peroxyformic Pulping of Agave Waste." Microscopy and Microanalysis 22, no. 5 (October 2016): 1084–97. http://dx.doi.org/10.1017/s1431927616011818.
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AbstractThe peroxyformic process is based on the action of a carboxylic acid (mainly formic acid) and the corresponding peroxyacid. The influences of processing time (60–180 min), formic acid concentration (80–95%), temperature (60–80°C), and hydrogen peroxide concentration (2–4%) on peroxyformic pulping of agave leaves were studied by surface response methodology using a face-centered factorial design. Empirical models were obtained for the prediction of yield,κnumber (KN) and pulp viscosity as functions of the aforementioned variables. Mathematical optimization enabled us to select a set of operational variables that produced the best fractionation of the material with the following results: pulp yield (26.9%), KN (3.6), and pulp viscosity (777 mL/g). Furthermore, this work allowed the description and evaluation of changes to the agave fibers during the fractionation process using different microscopic and spectroscopic techniques, and provided a comprehensive and qualitative view of the phenomena occurring in the delignification of agave fibers. The use of confocal and scanning electron microscopy provided a detailed understanding of the microstructural changes to the lignin and cellulose in the fibers throughout the process, whereas Raman spectroscopy and X-ray diffraction analysis indicated that cellulose in the pulp after treatment was mainly of type I.
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Strunk, Peter, Åsa Lindgren, Roland Agnemo, and Bertil Eliasson. "Properties of cellulose pulps and their influence on the production of a cellulose ether." Nordic Pulp & Paper Research Journal 27, no. 1 (January 1, 2012): 24–34. http://dx.doi.org/10.3183/npprj-2012-27-01-p024-034.
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Abstract Several grades of cellulose pulps were investigated for their influence on the product quality of a cellulose ether, ethyl-hydroxy-ethyl cellulose (EHEC). The selection of the pulps was based on pulping process, original wood type and intrinsic viscosity. In total, five sulfite pulps and four sulfate pulps were chosen, of which all but one sulfate pulp were of dissolving grade. The physical and chemical properties of the pulps were analyzed as well as important qualitative parameters of the final product EHEC. The influence of pulp properties on EHEC quality was investigated by multivariate data analyses. Principal component analysis showed that due to the influence of all variables, the pulps aligned in groups in accordance to the selection criteria pulping process and wood type. Partial least square regression revealed that high gel formation in EHEC is explained by the pulp properties high intrinsic viscosity and high Mw in combination with high caustic absorption rate and high total caustic absorption. The amount of hemicelluloses, in particular xylose, also contributed to gel formation. High cloud point for an EHEC solution was explained by a high MSEO and low DSEt of the EHEC molecules, where in turn a high MSEO could be predicted by a high pore area, high PD and a low caustic absorption rate. A low DSEt could on the other hand be predicted by a low hemicellulose content and hence a high R18. In a separate model, the same pulp properties explaining MSEO and DSEt also predicted cloud point directly. Fock reactivity and viscose dope filterability, both test methods originating from the viscose manufacturing, were shown to predict cloud point but have low predictability on other EHEC quality parameters. The models achieved can thus be utilized to predict final EHEC product qualities for new pulps within the design set of the chosen pulps.
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Mysov, Oleg, Igor Levchuk, Kseniia Fesenko, Mariia Savchenko, and Olena Gnatko. "DEVELOPMENT OF A COMPUTER MODEL FOR OBTAINING A SOLUTION OF COPPER SULFATE ADAPTED FOR SOLVING CONTROL PROBLEMS." HERALD OF KHMELNYTSKYI NATIONAL UNIVERSITY 299, no. 4 (October 2021): 59–66. http://dx.doi.org/10.31891/2307-5732-2021-299-4-59-66.
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Copper sulfate is an inorganic compound that is currently widely used in the chemical industry, medicine and agriculture. When developing systems for automated control of the process of obtaining copper sulfate, there is a need for simple, high-speed and at the same time accurate mathematical models that are used both in improving algorithms for optimal control of this process, and in developing operator interfaces and debugging control algorithms. At the same time, the development of full-fledged mathematical models of technological processes is a very laborious task that requires significant material and time costs. The subject of study in the article is a computer model of the process of obtaining a solution of copper sulfate, implemented in the software environment of the universal modeling program ChemCAD. The aim of the work is to develop in a software environment a universal modeling program ChemCAD, a computer model of the process of obtaining a solution of copper sulphate, adapted for solving problems of control and integration into modern SCADA systems. Objectives: to develop a computer model of the process of obtaining a solution of copper sulfate in the ChemCAD simulation program; explore the process using a computer model, get graphical dependencies that describe the main technological parameters of the process; perform a comparative analysis of the data obtained by calculation with the experimental data of the laboratory setup and draw a conclusion about the functionality of the developed computer model; adapt the computer model to solve the control problem and develop the principles of two-way information exchange of the computer model based on OPC technology with the modern SCADA system TRACE-MODE 6. The methods used are: computer modeling of technological processes; OPC technology; SCADA. Conclusions: the novelty of the results obtained is as follows. In the ChemCAD software environment, a computer model of the process of obtaining a solution of copper sulfate has been developed, adapted for solving control problems and integration into existing SCADA systems. The principles and structure of two-way information exchange of a computer model with external control programs based on OPC technology have been developed.
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Alkinani, Sadeem S., Mohamed F. El-Amin, and Tayeb Brahimi. "Numerical Modeling and Analysis of Harvesting Atmospheric Water Using Porous Materials." Separations 9, no. 11 (November 10, 2022): 364. http://dx.doi.org/10.3390/separations9110364.
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Nowadays, harvesting water from the atmosphere is becoming a new alternative for generating fresh water. To the author’s best knowledge, no mathematical model has been established to describe the process of harvesting water from the atmosphere using porous materials. This research seeks to develop a new mathematical model for water moisture absorption in porous materials to simulate and assess harvesting atmospheric water. The mathematical model consists of a set of governing partial differential equations, including mass conservation equation, momentum equation, associated parameterizations, and initial/boundary conditions. Moreover, the model represents a two-phase fluid flow that contains phase-change gas–liquid physics. A dataset has been collected from the literature containing five porous materials that have been experimentally used in water generation from the air. The five porous materials include copper chloride, copper sulfate, magnesium sulfate, manganese oxides, and crystallites of lithium bromide. A group of empirical models to relate the relative humidity and water content have been suggested and combined with the governing to close the mathematical system. The mathematical model has been solved numerically for different times, thicknesses, and other critical parameters. A comparison with experimental findings was made to demonstrate the validity of the simulation model. The results show that the proposed mathematical model precisely predicts the water content during the absorption process. In addition, the simulation results show that; during the absorption process, when the depth is smaller, the water content reaches a higher saturation point quickly and at a lower time, i.e., quick process. Finally, the highest average error of the harvesting atmospheric water model is around 1.9% compared to experimental data observed in manganese oxides.
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Lira, J. R., Fábio de Oliveira Arouca, João Jorge Ribeiro Damasceno, and L. C. Oliveira-Lopes. "Modeling of the Height of Sediment in a Continuous Thickener." Materials Science Forum 727-728 (August 2012): 1812–17. http://dx.doi.org/10.4028/www.scientific.net/msf.727-728.1812.
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Mathematical models for thickeners can be used for equipment design, to simulate the process operation, and to develop control strategies for a continuous operation. In this work, numerical simulation to obtain the final height of the sediment when operating at steady state conditions were performed using two mathematical models: the model introduced by Tiller and Chen (1988) and the one proposed by Arouca (2007). The simulated results were compared to experimental data obtained when the thickener was operated with and without the use of flocculent agent. The equipment used to obtain experimental data was a conventional thickener, built in acrylic. Aluminum sulfate was used in the experiments for the production of flocculated suspensions. The results showed that the Tiller and Chen (1988) model produced a deviation of 39.0% for kaolin suspensions and 14.3% when aluminum sulfate was added to the system. The Arouca (2007) model resulted in values much closer to those obtained experimentally, with deviations of less than 3% for kaolin suspensions regardless of the use of flocculent agent.
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Zhuchenko, Anatolii, Ruslan Osipa, Liudmyla Osipa, and Dmytro Kovaliuk. "Statics simulation of the sulphate iron-containing wastewater neutralization process." Proceedings of the NTUU “Igor Sikorsky KPI”. Series: Chemical engineering, ecology and resource saving, no. 4 (December 24, 2021): 15–21. http://dx.doi.org/10.20535/2617-9741.4.2021.248873.
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At the present stage of technical progress, all industries face an extremely complex problem of creating reliable barriers that prevent the penetration of industrial emissions into the environment. Currently, the issues of stabilizing the quality of wastewater treatment have become especially important in connection with the task of developing wastewater-free industrial complexes. Among the complex scientific and technical problems associated with this task, the problem of stable and reliable maintenance of water quality parameters at the outlet of technological systems is crucial, as leakage of pollutants immediately affects the state of basic production, disrupting its technology and infecting ecosystems.
The focus of industry on a sharp reduction in emissions and on the creation of industrial cycles with circulating water supply requires intensive efforts to improve the wastewater treatment technology, the introduction of high-performance processes and devices, as well as the synthesis of control systems for typical wastewater treatment processes.
For the performance of automated control systems for typical cleaning processes, it is necessary to develop a software package on the basis of appropriate mathematical models of typical processes. To obtain them, methods of mathematical and simulation modeling and variance analysis were used.
In order to assess the quality of modeling, the presented mathematical model describing the statics of the neutralization process for ferrous sulfate water was tested for compliance. To do this, two experiments were performed (the first at an initial concentration of sulfuric acid of 800 [mg/l] and ferrous sulfate of 4000 [mg/l] and the second at an initial concentration of sulfuric acid of 800 [mg/l] and ferrous sulfate of 2000 [mg/l]). First of all, a precondition for the reproducibility of experimental results was verified using the Cochrane test. The mathematical model was verified for adequacy on the basis of Fisher's criterion for the significance level q = 0.05 with degrees of freedom j1 = 16 and j2 = 17.
For the first experiment, Grozr = 0.50557 and Gmab = 0.73; i.e., Grozr < Gmab and dispersions are homogeneous. Frozr = 1.0225 and Fmab = 2.4 and thus Frozr < Fmab, and there is no reason to say that the model is inadequate.
For the second experiment, Grozr = 0.50308 and Gmab = 0.73; i.e., Grozr < Gmab and dispersions are also homogeneous. Frozr = 1.0005 and Fmab = 2.4 and thus Frozr < Fmab, which also indicates that the model is adequate.
The issue related to the performance of technological systems for wastewater treatment in non-stationary modes is directly dictated by the specific operating conditions of treatment facilities, which are expressed by the instability of parameters at their inlet. The inability to apply the necessary technological action to the flow in time is a serious obstacle to the implementation of the cleaning depth, which is guaranteed by the physicochemical basis of the methods incorporated in technological systems and requiring cleaning standards. The operator cannot handle this complex task manually. On the basis of the proposed mathematical model, a structural-parametric diagram of the automated process control system has been developed, which makes it possible to proceed to the elaboration of algorithms and software for the control system necessary for automated control of the wastewater treatment process.
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Vázquez-Guerrero, Adriana, Raúl Cortés-Martínez, Ruth Alfaro-Cuevas-Villanueva, Eric M. Rivera-Muñoz, and Rafael Huirache-Acuña. "Cd(II) and Pb(II) Adsorption Using a Composite Obtained from Moringa oleifera Lam. Cellulose Nanofibrils Impregnated with Iron Nanoparticles." Water 13, no. 1 (January 3, 2021): 89. http://dx.doi.org/10.3390/w13010089.
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This work informs on the green synthesis of a novel adsorbent and its adsorption capacity. The adsorbent was synthesized by the combination of iron nanoparticles and cellulose nanofibers (FeNPs/NFCs). Cellulose nanofibers (NFCs) were obtained from Moringa (Moringa oleifera Lam.) by a pulping Kraft process, acid hydrolysis, and ultrasonic methods. The adsorption method has advantages such as high heavy metal removal in water treatment. Therefore, cadmium (Cd) and lead (Pb) adsorption with FeNP/NFC from aqueous solutions in batch systems was investigated. The kinetic, isotherm, and thermodynamic parameters, as well as the adsorption capacities of FeNP/NFC in each system at different temperatures, were evaluated. The adsorption kinetic data were fitted to mathematical models, so the pseudo-second-order kinetic model described both Cd and Pb. The kinetic rate constant (K2), was higher for Cd than for Pb, indicating that the metal adsorption was very fast. The adsorption isotherm data were best described by the Langmuir–Freundlich model for Pb multilayer adsorption. The Langmuir model described Cd monolayer sorption. However, experimental maximum adsorption capacities (qe exp) for Cd (>12 mg/g) were lower than those for Pb (>80 mg/g). In conclusion, iron nanoparticles on the FeNP/NFC composite improved Cd and Pb selectivity during adsorption processes, indicating the process’ spontaneous and exothermic nature.
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Seckler, Marcelo Martins. "Crystallization in Fluidized Bed Reactors: From Fundamental Knowledge to Full-Scale Applications." Crystals 12, no. 11 (October 28, 2022): 1541. http://dx.doi.org/10.3390/cryst12111541.
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A review is presented on fifty years of research on crystallization in fluidized bed reactors (FBRs). FBRs are suitable for recovery of slightly soluble compounds from aqueous solutions, as it yields large, millimeter sized particles, which are suitable for reuse and permits low liquid residence times in the timescale of minutes. Full-scale applications for water softening have been applied since the 1980s, and since then, new applications have been developed or are in development for recovery of phosphorus, magnesium, fluoride, metals, sulfate, and boron. Process integration with membrane, adsorption, and biological processes have led to improved processes and environmental indicators. Recently, novel FBR concepts have been proposed, such as the aerated FBR for chemical-free precipitation of calcium carbonate, the seedless FBR to yield pure particulate products, a circulating FBR for economic recovery and extended use of seeds, as well as coupled FBRs for separation of chiral compounds and FBRs in precipitation with supercritical fluids. Advances are reported in the understanding of elementary phenomena in FBRs and on mathematical models for fluid dynamics, precipitation kinetics, and FBR systems. Their role is highlighted for process understanding, optimization and control at bench to full-scale. Future challenges are discussed.
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Hross, Sabrina, Fabian J. Theis, Michael Sixt, and Jan Hasenauer. "Mechanistic description of spatial processes using integrative modelling of noise-corrupted imaging data." Journal of The Royal Society Interface 15, no. 149 (December 2018): 20180600. http://dx.doi.org/10.1098/rsif.2018.0600.
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Spatial patterns are ubiquitous on the subcellular, cellular and tissue level, and can be studied using imaging techniques such as light and fluorescence microscopy. Imaging data provide quantitative information about biological systems; however, mechanisms causing spatial patterning often remain elusive. In recent years, spatio-temporal mathematical modelling has helped to overcome this problem. Yet, outliers and structured noise limit modelling of whole imaging data, and models often consider spatial summary statistics. Here, we introduce an integrated data-driven modelling approach that can cope with measurement artefacts and whole imaging data. Our approach combines mechanistic models of the biological processes with robust statistical models of the measurement process. The parameters of the integrated model are calibrated using a maximum-likelihood approach. We used this integrated modelling approach to studyin vivogradients of the chemokine (C-C motif) ligand 21 (CCL21). CCL21 gradients guide dendritic cells and are important in the adaptive immune response. Using artificial data, we verified that the integrated modelling approach provides reliable parameter estimates in the presence of measurement noise and that bias and variance of these estimates are reduced compared to conventional approaches. The application to experimental data allowed the parametrization and subsequent refinement of the model using additional mechanisms. Among other results, model-based hypothesis testing predicted lymphatic vessel-dependent concentration of heparan sulfate, the binding partner of CCL21. The selected model provided an accurate description of the experimental data and was partially validated using published data. Our findings demonstrate that integrated statistical modelling of whole imaging data is computationally feasible and can provide novel biological insights.
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Moroz, L. I., and A. G. Maslovskaya. "Fractional-Differential Model of Heat Conductivity Process in Ferroelectrics under the Intensive Heating Conditions." Mathematics and Mathematical Modeling, no. 2 (July 20, 2019): 29–47. http://dx.doi.org/10.24108/mathm.0219.0000185.
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Ferroelectrics, due a number of characteristics, behave as hereditary materials with fractal structure. To model mathematically the systems with so-called memory effects one can use the fractional time-derivatives. The pyro-electric properties of ferroelectrics arouse interest in developing the fractional-differential approach to simulating heat conductivity process.The present study deals with development and numerical implementation of fractal heat conductivity model for hereditary materials using the concepts of fractional-differential calculus applied to the simulation of intensive heating processes in ferroelectrics.The paper proposes a mathematical model governed through mixed initial-boundary value problem for partial differential equation containing a fractional time-derivative as well as nonlinear temperature dependence on the heat capacity. To solve the problem the computational algorithm was designed which is based on an analog of the Crank – Nicolson finite difference scheme combining with the Grunwald – Letnikov formula for fractional time-derivative approximation. The approximation of Neumann boundary condition is included into the finite difference problem statement using scheme of fictitious mesh points. The total system of linear algebraic equations is solved by sweep method.The designed application program allows one to perform the computer simulation of heat conductivity process in hereditary materials. The model verification was performed for numerical solving test problem with known analytical solution. The results of computational experiments are demonstrated for the example of estimating heat distribution in a typical ferroelectric crystal of TGS (triglycine sulfate) near the temperature of phase transition. The fractional derivative order was approximately evaluated to be ~0.7 at variation of this parameter. We applied the comparison of fractal model implementation results with experimental data related to the time when the ferroelectric crystal is heated to Curie temperature. These findings demonstrate that one needs to use the modified models at the analysis of the field effects arising in hereditary materials.
Dissertations / Theses on the topic "Sulfate pulping process Mathematical models"
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Mackinnon, John 1963. "Dynamic simulation of the first two stages of a kraft softwood bleach process." Thesis, McGill University, 1987. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=66188.
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Heazel, Thomas Edward. "Cell wall sulfur distribution in sulfonated southern pine latewood." Diss., Georgia Institute of Technology, 1988. http://hdl.handle.net/1853/5786.
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Burazin, Mark Alan. "A dynamic model of kraft-anthraquinone pulping." Diss., Georgia Institute of Technology, 1986. http://hdl.handle.net/1853/5743.
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Jones, Andrew K. "A Model of the kraft recovery furnace." Diss., Georgia Institute of Technology, 1989. http://hdl.handle.net/1853/5754.
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Kulas, Katherine A. "An overall model of the combustion of a single droplet of kraft black liquor." Diss., Available online, Georgia Institute of Technology, 1990:, 1990. http://etd.gatech.edu/theses/available/ipstetd-12/kulas%5Fka.pdf.
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Fan, Xiaolin. "Material flow in a wood-chip refiner." Thesis, McGill University, 1987. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=63977.
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Watson, Edward. "Mathematical modelling and experimental study of the kinetics of the acid sulphite pulping of eucalyptus wood." Thesis, 1992. http://hdl.handle.net/10413/7936.
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The chemistry of the batch cooking process at Sappi Saiccor, relating to both the pulp and liquor, was investigated with the aim of using kinetic expressions to develop an improved process control model. The mill produces dissolving pulps using the acid sulphite method. Three process reactions were identified as important: cellulose hydrolysis, delignification and hemicellulose dissolution. Of these, cellulose hydrolysis is the most important since the primary aim is to achieve a targeted cellulose degree of polymerisation (DP) or viscosity (DP is commonly expressed in terms
of this measurement). This is directly determined by the rate of this reaction during the cook, and the acidity of the cooking liquor was found to be the key factor. As existing equipment was not suitable for obtaining the data required to perform a kinetic analysis, a pilot plant was constructed. A commercially available probe was used for the first time to measure pH directly. The measured acidity is not directly equivalent to hydrogen ion activity at these temperatures and pressures; however, since the conditions of each cook are similar the errors incurred were found to be constant from cook to cook. The probe was found to be prone to drift due to ageing and this was accounted for by using an 'on line' calibration based on a liquor analysis.
The kinetics of the cellulose hydrolysis reaction were determined using the on-line measurement of acidity and the concept of degradation increase (DI) which relates the reduction in DP value to the rate at which the polymeric chains are split. Delignification and hemicellulose dissolution were examined, since it is beneficial to maximise these reactions to reduce the quantities of chemicals consumed during the bleaching process. A model for controlling cooks to a set target cellulose DP value within a set time was developed based on the reaction kinetics. This was capable of predicting cooking conditions required with sufficient accuracy to control the cellulose DP value to within ±6 cp SNIA on the viscosity scale.Thesis (M.Sc.Eng.)-University of Natal, 1992.
Books on the topic "Sulfate pulping process Mathematical models"
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Dibbs, Scott E. Modeling & simulation of the alkaline sulfite anthraquinone pulping system. 1985.
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Dibbs, Scott E. Modeling & simulation of the alkaline sulfite anthraquinone pulping system. 1985.
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