Journal articles on the topic 'Pyrolysis Mathematical models'
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Hernowo, Pandit, Carolus B. Rasrendra, Yogi W. Budhi, Jenny Rizkiana, Anton Irawan, Septhian Marno, Yana Meliana, Oki Muraza, and Yazid Bindar. "Volatile State Mathematical Models for Predicting Components in Biomass Pyrolysis Products." Journal of Engineering and Technological Sciences 54, no. 1 (February 2, 2022): 220108. http://dx.doi.org/10.5614/j.eng.technol.sci.2022.54.1.8.
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Volatile state mathematical models for quantifying the chemical components in volatile biomass pyrolysis products were developed. The component mass yield Yi rate depends linearly on its pseudo kinetic constant and the remaining mass yield. The mass fraction rate of each component was modeled from the derivation of its mass yield rate equation. A new mathematical model equation was successfully developed. The involved variables are: biomass number, temperature, heating rate, pre-exponential factor, and pseudo activation energy related to each component. The component mass fraction yi and the mass yield were predicted using this model within a temperature range. Available experimental pyrolysis data for beechwood and rice husk biomass were used to confirm the developed model. The volatile products were separated into bio-pyrolysis gas (BPG) and a bio-pyrolysis oil (BPO). Five components in the BPG and forty in the BPO were quantified. The pseudo activation energy for each pseudo chemical reaction for a specific component was modeled as a polynomial function of temperature. The component mass fraction and yield are quantifiable using this developed mathematical model equation within a temperature range. The predicted component mass fractions and yields agreed excellently with the available experimental data.
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Khaghanikavkani, Elham, and Mohammed M. Farid. "Mathematical Modelling of Microwave Pyrolysis." International Journal of Chemical Reactor Engineering 11, no. 1 (October 31, 2013): 543–59. http://dx.doi.org/10.1515/ijcre-2012-0060.
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Abstract This study deals with a detailed numerical investigation of the microwave heating process in plastic pyrolysis. The pyrolysis of high-density polyethylene (HDPE) was studied using a single-mode microwave cavity, TE10 mode, at 2.45 GHz with two different absorbents, as carbon and silicon carbide, and the results were compared. The temperature distribution inside the sample was determined by solving the conservation equations coupled with the microwave and chemical kinetic equations. Lambert’s law was applied to describe the electromagnetic field in the microwave cavity. The effective heat capacity method was used to account for the latent heat in the melting range of plastic. The heat of the reaction was taken into account using first-order kinetic equations assuming a single-step reaction. One-dimensional model equations were solved using the finite difference method utilising MATLAB codes. The model developed in this study provides a better understanding of the fundamental mechanisms of the microwave pyrolysis of HDPE based on a combination of electromagnetic field and thermal models. The primary focus was to incorporate and investigate the effect of the phase changes and reaction during microwave pyrolysis. The results show that the temperature profile strongly depends on the physical properties of the material. Silicon carbide provides more uniform heating distribution compared with carbon.
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Trninić, Marta. "Mathematical modelling of primary and secondary pyrolysis: State of the art." FME Transactions 48, no. 4 (2020): 733–44. http://dx.doi.org/10.5937/fme2004733t.
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Pyrolysis process converts biomass into liquid, gaseous and solid fuels. Chemical kinetics play a key role in explaining the characteristics of pyrolysis reactions and developing mathematical models. Many studies have been undertaken to understand the kinetics of biomass pyrolysis; however, due to the heterogeneity of biomass and the complexity of the chemical and physical changes that occur during pyrolysis, it is difficult to develop a simple kinetic model that is applicable in every case. In this review, different methods to describe biomass primary and secondary pyrolysis with different types of kinetic mechanisms are discussed.
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Assoumani, Nidhoim, Merlin Simo-Tagne, Fatima Kifani-Sahban, Ablain Tagne Tagne, Maryam El Marouani, Marcel Brice Obounou Akong, Yann Rogaume, Pierre Girods, and André Zoulalian. "Numerical Study of Cylindrical Tropical Woods Pyrolysis Using Python Tool." Sustainability 13, no. 24 (December 15, 2021): 13892. http://dx.doi.org/10.3390/su132413892.
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In this paper, the thermal behavior of large pieces of wood pyrolysis has been modeled. Two mathematical models coupling heat transfer equations to chemical kinetics were used to predict the pyrolytic degradation of a 25 mm radius wood sample, assumed to be dry in the first model and wet in the second, when heated to 973.15 K. The reactions involved in the pyrolysis process are assumed to be endothermic. The diffusion of bounded water during the process is taken into account in the second model, where the heat transfer equation has been coupled to that of the diffusion of moisture. This model, although simple, provides more information on the drying and pyrolysis processes during the heating of wood, which is its originality. It can therefore be advantageously used to calculate the temperature distribution in a pyrolysis bed. The equations of the two models, discretized by an explicit finite difference method, were solved numerically by a program written in Python. The validation of both models against experimental work in the literature is satisfactory. The two models allow examination of the temperature profile in the radial direction of wood samples and highlighting of the effect of temperature on some thermal, physical and physicochemical characteristics.
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Нурисламова, Л. Ф., and И. М. Губайдуллин. "Numerical analysis of parameter identifiability for a mathematical model of a chemical reaction." Numerical Methods and Programming (Vychislitel'nye Metody i Programmirovanie), no. 3 (July 25, 2018): 282–92. http://dx.doi.org/10.26089/nummet.v19r327.
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Авторами статьи ведутся работы, направленные на разработку численного подхода к анализу параметрической идентифицируемости модели химической реакции методами анализа чувствительности для эффективного исследования и управления процессом химической реакции. Целью настоящей работы является определение параметров, подлежащих идентификации в условиях задаваемой погрешности измерений, химической реакции на примере процесса пиролиза пропана и определение незначимых параметров модели. Выполнена редукция 157-стадийной детальной схемы пиролиза пропана к 30-стадийной схеме. Предложена кинетическая модель для анализа низкотемпературного пиролиза пропана. Модель адекватно описывает выход наблюдаемых продуктов реакции при атмосферном давлении. Идентифицированы параметры кинетической модели пиролиза пропана путем решения обратной задачи химической кинетики. The authors of this paper develop a numerical approach to analyze the parametric identifiability of chemical reaction models by the methods of sensitivity analysis for the efficient study and management of chemical reaction processes. The primary objective of this paper is to determine the parameters to be identified for the propylene pyrolysis process and to determine the insignificant parameters of the model. The 157-step detailed pyrolysis scheme of propane is reduced to the 30-step scheme. A kinetic model is proposed to analyze the low-temperature pyrolysis of propane. This model adequately describes the yield of observed reaction products at atmospheric pressure. The parameters of the kinetic model of propane pyrolysis are identified by solving the inverse problem of chemical kinetics.
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Alvarado Flores, José Juan, Jorge Víctor Alcaraz Vera, María Liliana Ávalos Rodríguez, Luis Bernardo López Sosa, José Guadalupe Rutiaga Quiñones, Luís Fernando Pintor Ibarra, Francisco Márquez Montesino, and Roberto Aguado Zarraga. "Analysis of Pyrolysis Kinetic Parameters Based on Various Mathematical Models for More than Twenty Different Biomasses: A Review." Energies 15, no. 18 (September 7, 2022): 6524. http://dx.doi.org/10.3390/en15186524.
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Today, energy use is an important and urgent issue for economic development worldwide. It is expected that raw material in the form of biomass and lignocellulosic residues will become increasingly significant sources of sustainable energy in the future because they contain components such as cellulose, hemicellulose, lignin, and extractables with high energy-producing potential. It is then essential to determine the behavior of these materials during thermal degradation processes, such as pyrolysis (total or partial absence of air/oxygen). Pyrolyzed biomass and its residual fractions can be processed to produce important chemical products, such as hydrogen gas (H2). Thermogravimetric (TGA) analysis and its derivative, DTG, are analytical techniques used to determine weight loss as a function of temperature or time and associate changes with certain degradation and mass conversion processes in order to evaluate kinetic properties. Applying kinetic methods (mathematical models) to degradation processes permits obtaining several useful parameters for predicting the behavior of biomass during pyrolysis. Current differential (Friedman) and integral (Flynn–Wall–Ozawa, Kissinger–Akahira–Sunose, Starink, Popescu) models vary in their range of heating speeds (β) and degree of advance (α), but some (e.g., Kissinger’s) do not consider the behavior of α. This article analyzes the results of numerous kinetic studies using pyrolysis and based on thermogravimetric processes involving over 20 distinct biomasses. The main goal of those studies was to generate products with high added value, such as bio-char, methane, hydrogen, and biodiesel. This broad review identifies models and determines the potential of lignocellulosic materials for generating bioenergy cleanly and sustainably.
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Ismailov, Bakhtiyar, Zhanat Umarova, Khairulla Ismailov, Aibarsha Dosmakanbetova, and Saule Meldebekova. "Mathematical modeling and algorithm for calculation of thermocatalytic process of producing nanomaterial." Indonesian Journal of Electrical Engineering and Computer Science 23, no. 3 (September 1, 2021): 1590. http://dx.doi.org/10.11591/ijeecs.v23.i3.pp1590-1601.
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<p>At present, when constructing a mathematical description of the pyrolysis reactor, partial differential equations for the components of the gas phase and the catalyst phase are used. In the well-known works on modeling pyrolysis, the obtained models are applicable only for a narrow range of changes in the process parameters, the geometric dimensions are considered constant. The article poses the task of creating a complex mathematical model with additional terms, taking into account nonlinear effects, where the geometric dimensions of the apparatus and operating characteristics vary over a wide range. An analytical method has been developed for the implementation of a mathematical model of catalytic pyrolysis of methane for the production of nanomaterials in a continuous mode. The differential equation for gaseous components with initial and boundary conditions of the third type is reduced to a dimensionless form with a small value of the peclet criterion with a form factor. It is shown that the laplace transform method is mainly suitable for this case, which is applicable both for differential equations for solid-phase components and calculation in a periodic mode. The adequacy of the model results with the known experimental data is checked.</p>
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Makoba, Mmoloki, Daniel Erich Botha, Mpho Thabang Rapoo, László Zsolt Szabó, Thapelo Shomana, Paul Serban Agachi, and Edison Muzenda. "A Review on Botswana Coal Potential from a Pyrolysis and Gasification Perspective." Periodica Polytechnica Chemical Engineering 65, no. 1 (July 6, 2020): 80–96. http://dx.doi.org/10.3311/ppch.12909.
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Coal pyrolysis and gasification are promising options for the future of Botswana as the country has large coal reserves with severe limitations in terms of export options. Coal characterization facilities will be required in order to harness its full potential and methods such as proximate, ultimate and chemical structure analysis (FTIR, Raman spectroscopy and X-ray diffraction techniques) were investigated. The paper presents a brief history of pyrolysis and gasification, typical types of the reactors as well as factors that influence product selection for Botswana coal. Coal pyrolysis and gasification are complex processes and it is difficult to define the mechanisms of product formation. However, there are several kinetic models that are relevant to the sub-bituminous coal of Botswana which were proposed by researchers to describe the formation of the compounds and mathematical models that were validated by other researchers on mass and heat transfer as also presented herein.
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Szubel, M., A. Dernbecher, and T. Dziok. "Determination of kinetic parameters of pyrolysis of wheat straw using thermogravimetry and mathematical models." IOP Conference Series: Earth and Environmental Science 214 (January 23, 2019): 012131. http://dx.doi.org/10.1088/1755-1315/214/1/012131.
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Донской, Игорь Геннадьевич. "Mathematical modelling of woody particles pyrolysis in a fixed bed." Вычислительные технологии, no. 6(23) (January 16, 2019): 14–24. http://dx.doi.org/10.25743/ict.2018.23.6.003.
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Рассмотрена задача термического разложения совокупности последовательно расположенных древесных частиц с учетом внешнего тепломассообмена с газовым потоком и внутренних физико-химических процессов (теплопроводность, диффузия, фильтрация, сушка и химическая реакция). Математическая модель строится из субмоделей одиночных частиц, сопряженных по потокам теплоты и массы. Результаты численных расчетов позволяют исследовать динамическое поведение частиц в условиях плотного слоя, что представляет интерес при проектировании малых энергетических установок на биотопливе. The development of new energy technologies requires the improvement of mathematical models to describe the physical and chemical processes taking place in power plants. The process of wood particles fixed-bed pyrolysis is investigated in this paper: this process takes place both in the traditional combustion of wood fuels in fixed-bed boilers and in energotechnology processes aimed at producing combustible gases and chemical products (tar, charcoal). The problem of pyrolysis of a set of successively located wood particles is considered. Each particle is considered as an object with an internal distribution of temperature, pressure and concentrations. A system of equations is constructed for a single particle, including external heat and mass transfer between the particles and the ambient gas flow combined with internal physicochemical processes (heat conduction, diffusion, filtration, drying and chemical brutto-reaction of the organic mass decomposition producing gases and solid residue). The temperature of the gas in the pores of the particles is equal to the temperature of the solid. Using the model of pyrolysis of a single particle, it is possible to reproduce the known experimental data. The mathematical model of a fixed-bed pyrolysis is based on submodels of single particles, conjugated over heat and mass flows. The interaction between the particles composing the layer is reduced to heat fluxes: radiant heat transfer between the surfaces of adjacent particles occurs in the bed, as well as convective heat transfer between the heated gas and particles. The result is that each next particle layer is heated at a smaller temperature difference. On the one hand, the intensity of heat transfer decreases, on the other hand, the efficiency of using heat increases. The results of numerical calculations make it possible to study the dynamic behavior of particles in a fixed bed, which is of interest in the design of small power plants using biofuels.
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Olalo, Joselito Abierta. "Pyrolytic Oil Yield from Waste Plastic in Quezon City, Philippines: Optimization Using Response Surface Methodology." International Journal of Renewable Energy Development 11, no. 1 (December 3, 2021): 325–32. http://dx.doi.org/10.14710/ijred.2022.41457.
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Plastics play an essential role in packaging materials because of their durability to different environmental conditions. With its importance in the community lies the problem with waste disposal. Plastic is a non-biodegradable material, making it a big problem, especially when thrown in dumpsites. In solving the plastic problem, one efficient way to reduce its volume is through thermal processing such as pyrolysis. This study used the pyrolysis method to recover energy from plastic waste. Liquid oil from plastic was comparable to regular fuel used in powering engines. Before the pyrolysis process, a 3k factorial Box-Behnken Design was used in determining the number of experiments to be used. The output oil yield in each pyrolysis runs was optimized in different parameters, such as temperature, residence time, and particle size using response surface methodology to determine the optimum oil yield. Between polyethylene (PE), mixed plastic, and polystyrene (PS), PS produced its highest oil yield of 90 %. In comparison, mixed plastic produced only its highest oil yield of 45 % in 500 ºC temperature, 120 min residence time, and 3 cm particle size. The produced quadratic mathematical models in PE, mixed, and PS plastic were significant in which the p-values were less than 0.05. Using mathematical models, the optimum oil yield for PE (467.68 ºC, 120 min residence time, 2 cm particle size), mixed (500 ºC, 120 min residence time, 2.75 cm particle size) and PS plastic (500 ºC, 120 min residence time, 2 cm particle size) were 75.39 %, 46.74 %, and 91.38 %, respectively
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Ojolo, S. J., C. A. Osheku, and M. G. Sobamowo. "Analytical Investigations of Kinetic and Heat Transfer in Slow Pyrolysis of a Biomass Particle." International Journal of Renewable Energy Development 2, no. 2 (June 17, 2013): 105–15. http://dx.doi.org/10.14710/ijred.2.2.105-115.
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The utilization of biomass for heat and power generation has aroused the interest of most researchers especially those of energy .In converting solid fuel to a usable form of energy,pyrolysis plays an integral role. Understanding this very important phenomenon in the thermochemical conversion processes and representing it with appropriate mathematical models is vital in the design of pyrolysis reactors and biomass gasifiers. Therefore, this study presents analytical solutions to the kinetic and the heat transfer equations that describe the slow pyrolysis of a biomass particle. The effects of Biot number, temperature and residence time on biomass particle decomposition were studied. The results from the proposed analytical models are in good agreement with the reported experimental results. The developed analytical solutions to the heat transfer equations which have been stated to be “analytically involved” showed average percentageerror and standard deviations 0.439 and 0.103 from the experimental results respectively as compared with previous model in literature which gives average percentage error and standard deviations 0.75 and 0.106 from the experimental results respectively. This work is of great importance in the design of some pyrolysis reactors/units and in the optimal design of the biomass gasifiers.
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Mitrofanov, A. V., O. V. Sizova, N. S. Shpeynova, and V. A. Katyushin. "Mathematical modeling and analysis of operation of cylindric pyrolysis reactor with radial heating." Vestnik IGEU, no. 5 (October 31, 2021): 60–67. http://dx.doi.org/10.17588/2072-2672.2021.5.060-067.
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The vector of development of solid-fuel energy is currently directed towards expanding the range of renewable fuels used. Along with the direct combustion of fuel, the processes of controlled thermal transformation of the raw biomass in an oxygen-free surrounding to obtain a new fuel based on it (liquid, solid, gaseous) are widely spread. A significant part of research in this sphere is related to the study of the formal kinetics of such processes, at the same time, the hardware design of the process is no less important, but less studied. Thus, development of mathematical models of pyrolysis equipment operation is relevant. A decisive difference approximation of these processes in the framework of an axisymmetric formulation of the problem is chosen as a mathematical basis for modeling physical and chemical transformations and transfer processes in the radial direction of a cylindrical pyrolysis reactor. The material constants of the processes are borrowed from the well-known literature references The authors studied the modes of reactor operation not covered by a full-scale experiment, using the previously proposed and verified one-dimensional mathematical model of a cylindrical pyrolysis reactor. The issues of the influence of the dimensionless kinetic function of the process (reaction model) on the thermal transformation of the material in the apparatus are considered. The significant influence of the chosen reaction model on the kinetic nature of the process is pointed out. The mutual influence of drying and pyrolysis the presence of which is due to the energy effects of the processes is considered. A significant spatial heterogeneity of the process is defined and the possibility of the existence of a non-trivial effect of advanced heating of the internal zones of the apparatus in comparison with the peripheral ones is specified. The paper shows that a computational experiment can help to detect non-trivial effects and identify the variability of the process implementation even within the framework of a single design and technological solution of the pyrolysis process. According to the authors, the results of the obtained numerical experiments indicate that mathematical modeling can be the basis of making technological solution. However, further research is also needed to determine reliably the material constants of the process.
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Li, Shi, Xi Ju Zong, and Yan Hu. "Modeling and Control of Sludge Pyrolysis in a Fluidized Bed Reactor." Advanced Materials Research 846-847 (November 2013): 69–72. http://dx.doi.org/10.4028/www.scientific.net/amr.846-847.69.
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This paper is concerns with the study of modeling and control of sludge pyrolysis in a fluidized bed reactor. Firstly, a mathematical model is established for sludge pyrolysis in a fluidized bed furnace, mass balance and energy equations are established. Then, the model is linearized at the steady-state point, two linear models are derived: state space model and transfer function model. The transfer function model is used in internal model control (IMC), where the filter parameter is selected and discussed. The state space model is applied in model predictive control (MPC), where controller parameters of prediction horizon length and control horizon length are discussed.
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Zhdanova, Alena, Geniy Kuznetsov, Jean Legros, and Pavel Strizhak. "Thermal conditions for stopping pyrolysis of forest combustible material and applications to firefighting." Thermal Science 21, no. 6 Part A (2017): 2565–77. http://dx.doi.org/10.2298/tsci151006121z.
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Five models describing heat transfer during evaporation of the water sprayed over the forest to stop fires and to cool down the pyrolysis of the bio- top layer are established and investigated by a parametric approach. It aims to improve the understanding of the behaviour and the properties of the forest combustible material. A mathematical description of forest combustible material surfaces (needles of pine and fir-tree, leaves of birch) is established. The characteristic time, td, to cool down the forest combustible material layer below the temperature of the onset of the pyrolysis is the important parameter investigated in the present work. The effective conditions were determined allowing to reach the shortest td and the lowest consumption of e. g. water to be dropped.
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Baranovskiy, Nikolay, and Viktoriya Kirienko. "Mathematical Simulation of Forest Fuel Pyrolysis in One-Dimensional Statement Taking into Account Soot Formation." Processes 9, no. 9 (September 8, 2021): 1616. http://dx.doi.org/10.3390/pr9091616.
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Pyrolysis (thermal decomposition) is considered as the most important stage of a forest fire before direct forest fuel ignition. This process is accompanied by soot particle formation. Such particles have a negative impact on public health in the vicinity of forest fires. The purpose of this article was to investigate the heat and mass transfer process occurring in a typical forest fuel element (birch leaf). The pyrolysis and soot formation processes were taken into account, and various forest fire scenarios were considered. Computational experiments were carried out using the high-level programming language Delphi. Heat and mass transfer processes were described by nonlinear non-stationary differential heat conduction equations with corresponding initial and boundary conditions. The differential equations were solved by the finite difference method. Nonlinearity was resolved using a simple iteration. The main results of the research were (1) physical and mathematical models proposed for modeling forest fuel pyrolysis, taking into account soot formation and conditions corresponding to various forest fires; (2) a computer program coded in the high-level programming language Delphi; (3) the obtained temperature distributions over leaf thickness; (4) volume fractions obtained for various components dependent on time and space coordinates. The qualitative analysis of the dependencies showed that the temperature distributions in the birch leaf structure are similar for all forest fire types and differ only in absolute value. The intensity of the soot formation process directly depends on the forest fire type. The presented results should be useful in predicting and assessing forest fire danger, including near the facilities of the Russian Railways.
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Shakirov, S. R., A. G. Kvashnin, and A. V. Pisarev. "Research and Development of Mathematical Models of Elements of a Gas-Air Flow for Improvement of Automatic Control System of Organic Waste Processing Plant." Mekhatronika, Avtomatizatsiya, Upravlenie 21, no. 10 (October 7, 2020): 575–83. http://dx.doi.org/10.17587/mau.21.575-583.
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Recycling of organic wastes is an extremely important and challenging environmental task. One of the promising trends in this field is the creation of multi-mode (combustion, pyrolysis and gasification) plants for processing organic wastes with production of such useful products as thermal energy and energy carriers (biocoal, bio-oil, pyrolysis resins, synthesis gas, etc.) and fertilizers. When creating such plants, the main problems include instability of the properties of a source material, its high water and ash content. This drives the developers to use non-standard equipment and atypical control algorithms, the creating of which requires a lot of experimental work to be done. At the same time, conducting field experiments is an expensive, difficult and long process that highlights the need for extensive use of mathematical and computer modeling. In this paper, mathematical models of elements of the gas-air path of the organic waste processing plant are obtained. The characteristics of the gas-air path of the plant as of an object of regulation for pressure in the lower and vacuum in the upper part of the combustion chamber are determined. The gas-air flow consists of the flue and the air ducts and serves to remove flue gases from the combustion chamber and supply air needed to maintain fuel combustion. When developing new automation systems, modeling allows assessing the applied solutions accurately, simplifying and reducing the cost of their development, solving the problems of system stability, optimizing transient processes, etc. The nonlinearity of the obtained mathematical models on the "the pressure at the inlet to the n-th section air-gas flow path — the pressure at the outlet of the n-th section of the air-gas flow path" channels, the nonstationarity of objects of control and dependence of their dynamic characteristics on operating mode of the plant are determined. Due to developed models, the two-way relationship of the gas and air paths has been revealed. When modeling, the gas-air flow of the plant is divided into several sections for which the mathematical models are obtained. They are required to synthesize controllers of flue gases vacuum in the upper part and the air pressure in the lower part of the combustion chamber.
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Syguła, Ewa, Kacper Świechowski, Paweł Stępień, Jacek A. Koziel, and Andrzej Białowiec. "The Prediction of Calorific Value of Carbonized Solid Fuel Produced from Refuse-Derived Fuel in the Low-Temperature Pyrolysis in CO2." Materials 14, no. 1 (December 24, 2020): 49. http://dx.doi.org/10.3390/ma14010049.
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The decrease in the calorific value of refuse-derived fuel (RDF) is an unintended outcome of the progress made toward more sustainable waste management. Plastics and paper separation and recycling leads to the overall decrease in waste’s calorific value, further limiting its applicability for thermal treatment. Pyrolysis has been proposed to densify energy in RDF and generate carbonized solid fuel (CSF). The challenge is that the feedstock composition of RDF is variable and site-specific. Therefore, the optimal pyrolysis conditions have to be established every time, depending on feedstock composition. In this research, we developed a model to predict the higher heating value (HHV) of the RDF composed of eight morphological refuse groups after low-temperature pyrolysis in CO2 (300–500 °C and 60 min) into CSF. The model considers cardboard, fabric, kitchen waste, paper, plastic, rubber, PAP/AL/PE (paper/aluminum/polyethylene) composite packaging pack, and wood, pyrolysis temperature, and residence time. The determination coefficients (R2) and Akaike information criteria were used for selecting the best model among four mathematical functions: (I) linear, (II) second-order polynomial, (III) factorial regression, and (IV) quadratic regression. For each RDF waste component, among these four models, the one best fitted to the experimental data was chosen; then, these models were integrated into the general model that predicts the HHV of CSF from the blends of RDF. The general model was validated experimentally by the application to the RDF blends. The validation revealed that the model explains 70–75% CSF HHV data variability. The results show that the optimal pyrolysis conditions depend on the most abundant waste in the waste mixture. High-quality CSF can be obtained from wastes such as paper, carton, plastic, and rubber when processed at relatively low temperatures (300 °C), whereas wastes such as fabrics and wood require higher temperatures (500 °C). The developed model showed that it is possible to achieve the CSF with the highest HHV value by optimizing the pyrolysis of RDF with the process temperature, residence time, and feedstock blends pretreatment.
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Quesada, L., A. Pérez, V. Godoy, F. J. Peula, M. Calero, and G. Blázquez. "Optimization of the pyrolysis process of a plastic waste to obtain a liquid fuel using different mathematical models." Energy Conversion and Management 188 (May 2019): 19–26. http://dx.doi.org/10.1016/j.enconman.2019.03.054.
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Alvarado Flores, José Juan, José Guadalupe Rutiaga Quiñones, María Liliana Ávalos Rodríguez, Jorge Víctor Alcaraz Vera, Jaime Espino Valencia, Santiago José Guevara Martínez, Francisco Márquez Montesino, and Antonio Alfaro Rosas. "Thermal Degradation Kinetics and FT-IR Analysis on the Pyrolysis of Pinus pseudostrobus, Pinus leiophylla and Pinus montezumae as Forest Waste in Western Mexico." Energies 13, no. 4 (February 21, 2020): 969. http://dx.doi.org/10.3390/en13040969.
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For the first time, a study has been carried out on the pyrolysis of wood residues from Pinus pseudostrobus, Pinus leiophylla and Pinus montezumae, from an area in Western México using TGA analysis to determine the main kinetic parameters (Ea and Z) at different heating rates in a N2 atmosphere. The samples were heated from 25 °C to 800 °C with six different heating rates 5–30 °C min−1. The Ea, was calculated using different widely known mathematical models such as Friedman, Flynn-Wall-Ozawa and Kissinger-Akahira-Sunose. The Ea value of 126.58, 123.22 and 112.72 kJ/mol (P. pseudostrobus), 146.15, 143.24 and 132.76 kJ/mol (P. leiophylla) and 148.12, 151.8 and 141.25 kJ/mol (P. montezumae) respectively, was found for each method. A variation in Ea with respect to conversion was observed with the three models used, revealing that pyrolysis of pines progresses through more complex, multi-stage kinetics. FT-IR spectroscopy was conducted to determine the functional groups present in the three species of conifers. This research will allow future decisions to be made, and possibly, to carry out this process in a biomass reactor and therefore the production of H2 for the generation of energy through a fuel cell.
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Świechowski, Kacper, Marek Liszewski, Przemysław Bąbelewski, Jacek Koziel, and Andrzej Białowiec. "Oxytree Pruned Biomass Torrefaction: Mathematical Models of the Influence of Temperature and Residence Time on Fuel Properties Improvement." Materials 12, no. 14 (July 10, 2019): 2228. http://dx.doi.org/10.3390/ma12142228.
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Biowaste generated in the process of Oxytree cultivation and logging represents a potential source of energy. Torrefaction (a.k.a. low-temperature pyrolysis) is one of the methods proposed for the valorization of woody biomass. Still, energy is required for the torrefaction process during which the raw biomass becomes torrefied biomass with fuel properties similar to those of lignite coal. In this work, models describing the influence of torrefaction temperature and residence time on the resulting fuel properties (mass and energy yields, energy densification ratio, organic matter and ash content, combustible parts, lower and higher heating values, CHONS content, H:C and O:C ratios) were proposed according to the Akaike criterion. The degree of the models’ parameters matching the raw data expressed as the determination coefficient (R2) ranged from 0.52 to 0.92. Each model parameter was statistically significant (p < 0.05). Estimations of the value and quantity of the produced torrefied biomass from 1 Mg of biomass residues were made based on two models and a set of simple assumptions. The value of torrefied biomass (€123.4·Mg−1) was estimated based on the price of commercially available coal fuel and its lower heating value (LHV) for biomass moisture content of 50%, torrefaction for 20 min at 200 °C. This research could be useful to inform techno-economic analyses and decision-making process pertaining to the valorization of pruned biomass residues.
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Daňo, Martin, Eva Viglašová, Michal Galamboš, Karel Štamberg, and Jan Kujan. "Surface Complexation Models of Pertechnetate on Biochar/Montmorillonite Composite—Batch and Dynamic Sorption Study." Materials 13, no. 14 (July 12, 2020): 3108. http://dx.doi.org/10.3390/ma13143108.
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The study summarizes the results of monitoring the properties of two types of sorbents, BC1 (biochar sample 1) and BC2a (biochar sample 2), prepared by pyrolysis of bamboo biomass (BC1) and as its composite with montmorillonite K10 (BC2a). The main goal was to study their applicability to the Tc (VII) separation from liquid wastes, using NH4ReO4 as a carrier. The research was focused on determining the sorbents surface properties (by XRF (X-ray fluorescence) method and potentiometric titration in order to determine the properties of surface groups—Chemical Equilibrium Model (CEM) and Ion Exchange Model (IExM) models were applied here). As well as monitoring Tc (VII) (+Re(VII)) sorption, especially to determine equilibrium isotherm, the influence of pH and kinetics. The subject of research was also the dynamics of sorption, including its mathematical–physical modeling. Both sorbents have good properties against Tc (VII), however BC2a, due to the presence of montmorillonite, is more advantageous in this respect. It has a higher sorption capacity and faster kinetic investigation. An important finding is that the optimal pH is 2–3, which is related not only to the protonation of surface groups (they have a positive charge), but also to the negative form of the existence of Tc (VII) and Re (VII): TcO4− and ReO4−.
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Yi, Sung-Chul, Eun-Seok Song, and Mohammad R. Hajaligol. "Mathematical Model of Smoldering Combustion in a Carbonaceous Porous Medium Part 1 – Development of Pyrolysis and Combustion Models for a Cylindrical Geometry." Journal of Fire Sciences 19, no. 6 (November 2001): 429–48. http://dx.doi.org/10.1177/073490401773732436.
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Prado, Raquel, Lisa Weigand, Shikh M. S. N. S. Zahari, Xabier Erdocia, Jason Hallett, Jall Labidi, and Tom Welton. "An easy and reliable method for syringyl: guaiacyl ratio measurement." March 2017 16, no. 03 (2017): 145–52. http://dx.doi.org/10.32964/tj16.3.145.
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Lignin structure elucidation is one of the main targets for biorefinery related research. Because of its complexity, obtaining reproducible results in a straight-forward way is very important. One of the values that is used to compare different lignins is the syringyl:guaiacyl (S/G) ratio, which has been measured in different ways. The most reliable result is obtained for nitrobenzene oxidation, but this involves a complex process. In this work, the S/G ratios measured by pyrolysis-gas chromatography mass spectrometry (py-GCMS) and heteronuclear single quantum coherence-nuclear magnetic resonance (HSQC-NMR) spectroscopy were compared with attenuated total reflection infrared (ATR-IR) spectroscopy results to establish a reliable, quick, and simple method for the measurement. To achieve this, two mathematical models were applied with multivariate data analysis software. A partial least squares regression model for py-GCMS gave the best result.
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Saidi, MS, A. Mhaisekar, MR Hajaligol, and M. Subbiah. "Mathematical Modeling of a Lit-End Cigarette: Puffing Cycle and Effects of Puff Counts." Beiträge zur Tabakforschung International/Contributions to Tobacco Research 23, no. 1 (April 1, 2008): 46–62. http://dx.doi.org/10.2478/cttr-2013-0847.
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AbstractThe burning cycles of a lit-end cigarette were numerically simulated using a 3-D model that includes both the cigarette and its surrounding ambient air and the effects of buoyancy forces. The solid and gas phases were treated separately in a thermally non-equilibrium environment. The tobacco pyrolysis and char oxidation were modeled using multi-precursor models. The changes in tobacco column porosity and its subsequent effects on permeability and gas diffusivity were included. The mass, momentum, energy, and species transport equations were solved in a discretized computational domain using a commercially available computational fluid dynamics (CFD) code. The model was applied to puff a cigarette under different puffing intensities and the effects of puff volume, puff profile, and puff duration were studied. The results show that the model is capable of reproducing the major features of a burning cigarette during both smoldering and puffing. For the puffing and puff-by-puff cases, the solid and gas temperatures as well as those mainstream smoke constituents predicted by the model are in a good agreement with experimental results. A parametric study shows the significant effect of puff volume, puff profile, ventilation rate, and puff counts on solid and gas phase temperatures as well as gaseous species concentrations and mainstream smoke delivery. The buoyancy forces have shown to be very important in both smoldering and puffing.
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Abbas, A. H., M. Fadhil, Mohmd Shiraz Aris, A. B. A. Ibrahim, and Mohammed Termzy Nor Aniza. "A Non-Isothermal Thermo Gravimetric Kinetic Analysis of Malaysian Poultry-Processing-Dewatered-Sludge." Advanced Materials Research 970 (June 2014): 217–23. http://dx.doi.org/10.4028/www.scientific.net/amr.970.217.
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Poultry processing dewatered sludge which consisting of trimmings, fat, feathers and liquid discharges from processing slaughtered chicken is typically land filled in specialized sites. It is a costly process to manage and if not handled according to stringent procedures can be harmful to the surrounding environment. The use of this waste material as an alternative fuel can be an effective solution, as it not only contributes as an energy source but also solves environmental issues related to poultry sludge disposal. Combustion, gasification and pyrolysis are efficient techniques of utilizing energy effectively from poultry sludge. The performances of mathematical models to predict the product gas quality is rely on characterization of feed materials as well as the reaction kinetics of their thermal degradation. The aim of this study is to determine selected physical and chemical properties of poultry sludge associated with thermochemical conversion. Thermogravimetric analyses were performed at heating rates of 10, 20, 30, and 40 K/min in an air (oxidizing) atmosphere. The parameters of the reaction kinetics such as activation energy and reaction order were obtained by the application of OzawaFlynn Wall and Vyazovkin kinetic models.
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Director, L. B., K. A. Homkin, I. L. Maikov, Yu L. Shekhter, G. F. Sokol, and V. M. Zaichenko. "Theoretical and Experimental Investigations of Substantiating Technologies for Carbon Materials Production from Natural Gas." Eurasian Chemico-Technological Journal 5, no. 1 (July 12, 2017): 29. http://dx.doi.org/10.18321/ectj587.
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The results of theoretical and experimental investigations on methane pyrolysis with infiltration through a heated porous matrix generated from various carbon materials are presented. The features of mathematical<br />models, kinetic relationships of process are discussed. The mathematical model of process shares on external problem (a flow of particles in an external stream) and internal problem (reaction in particle porous). The<br />heat and mass transfer for the average (over the reactor cross section) parameters, ignoring the heat transfer in gas by thermal conductivity, is described by unsteady-state one-dimensional differential equations in<br />partial derivatives. For the mathematical description of process kinetics of methane decomposition the approach is used by which the soot formation is treated as a chain radical process. The porous media is represented by a system of large enough particles. In its turn, every macroparticle consists of finer particles, which are also composed of microparticles, etc. Calculating programs were used for modeling and efficiency analysis of technological installations for technical carbon production in a regenerative heater, filled by a ceramic nozzle and for similar purposes concerning carbon (oven soot) in autothermal torch process of partial gas oxidation by air at a surplus factor of oxidizer in relation to stoichiometry 0.4-0.5 at pressure close to atmospheric on Sosnogorsk Gas-Processing Plant. Experiment descriptions and techniques for experimental realization are given. These results are used as fundamentals for new technologies considering pyrocarbon materials production in the continuous operation reactor.
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Razd'yakonova, G. I., and V. F. Surovikin. "The Synthesis of Different Forms of Electrically Conductive Carbon Black by the Thermo-Oxidative Pyrolysis of Hydrocarbons. Phenomenological and Mathematical Models of the Synthesis Process." International Polymer Science and Technology 40, no. 3 (March 2013): 37–42. http://dx.doi.org/10.1177/0307174x1304000309.
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Netzer, Corinna, and Terese Løvås. "Chemical Model for Thermal Treatment of Sewage Sludge." ChemEngineering 6, no. 1 (February 7, 2022): 16. http://dx.doi.org/10.3390/chemengineering6010016.
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Sewage sludge is here studied as a valuable source for processing or energy conversation thanks to its high nutrition and energy content. However, various origins of the wastewater, different water cleaning technologies, and seasonal and regional dependencies lead to the high variability of the sewage sludge properties. In thermal treatment units, that is, incineration, gasification and pyrolysis, sewage sludge serves as feedstock or fuel, hence a proper characterization and a mathematical description of the sewage sludge are required to estimate product streams and to formulate numerical simulations and optimization methods. The presented work introduces a surrogate concept that allows replication of sewage sludge’s ultimate composition, moisture, and ash content. The surrogate approach aims to model the decomposition of any sewage sludge sample, opposite to the established determination of kinetic rates for individual samples. Based on chemical solid surrogate species and corresponding reaction mechanisms, the thermal decomposition path is described. Sewage sludge is represented by a combination of lignocellulosic species, proteins, sugars, lipids, and representative inorganic species. The devolatilization and heterogeneous reactions are formulated such that they can be used together with a detailed gas-phase model, including tar oxidation and emission models for nitrogen and sulfur oxides, recently proposed by the authors. The developed chemical model is applied using a zero-dimensional gasification reactor in order to model weight loss within the thermogravimetric analysis, pyrolysis, gasification and combustion conditions. Weight loss, the composition of product gases, and emission release (nitrogen and sulfur oxides) are captured well by the model. The flexible surrogate approach allows us to represent various sewage sludge samples.
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S. Valliammai, K. Gopal, R. Nithya, L. Rama Priya, and D. Kavitha. "Continuous Fixed-Bed Column Studies of Textile Effluent Treatment using Multi-Walled Carbon Nanotubes Originated from Rosmarinus officinalis Oil." Journal of Environmental Nanotechnology 10, no. 4 (January 6, 2022): 22–30. http://dx.doi.org/10.13074/jent.2021.12.214444.
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A continuous adsorption study in a fixed-bed column was carried out using Multi-walled Carbon Nanotubes derived from Rosmarinus officinalis oil as an adsorbent for removing the textile dye Acid blue 40 from an aqueous solution. The adsorbent, MWNTs were prepared from Rosmarinus officinalis oil as a precursor to Fe/Mo catalyst supported on silica at 650 ºC under N2 atmosphere by spray pyrolysis process characterized by scanning electron microscopy, Transmission Electron microscopy, and Raman spectroscopy. The effects of adsorbent bed height (2–6 cm), initial ion concentration (20– 60 mg/L), and flow rate (10–30 mL/min) on the column performance were analyzed. The breakthrough curve was analyzed using the mathematical models of Thomas, Yoon-Nelson, and bed depth service time. The Thomas model at different conditions defined the behaviors of the breakthrough curves. The bed depth service time model showed good agreement with the experimental data. The high values of correlation coefficients (R2 0.9875) obtained indicate the validity of the bed depth service time model for the present column system.
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Zamani, Seyed Ali, Robiah Yunus, A. W. Samsuri, M. A. Mohd Salleh, and Bahareh Asady. "Removal of Zinc from Aqueous Solution by Optimized Oil Palm Empty Fruit Bunches Biochar as Low Cost Adsorbent." Bioinorganic Chemistry and Applications 2017 (2017): 1–9. http://dx.doi.org/10.1155/2017/7914714.
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This study aims to produce optimized biochar from oil palm empty fruit bunches (OPEFB), as a green, low cost adsorbent for uptake of zinc from aqueous solution. The impact of pyrolysis conditions, namely, highest treatment temperature (HTT), heating rate (HR), and residence time (RT) on biochar yield and adsorption capacity towards zinc, was investigated. Mathematical modeling and optimization of independent variables were performed employing response surface methodology (RSM). HTT was found to be the most influential variable, followed by residence time and heating rate. Based on the central composite design (CCD), two quadratic models were developed to correlate three independent variables to responses. The optimum production condition for OPEFB biochar was found as follows: HTT of 615°C, HR of 8°C/min, and RT of 128 minutes. The optimum biochar showed 15.18 mg/g adsorption capacity for zinc and 25.49% of yield which was in agreement with the predicted values, satisfactory. Results of the characterization of optimum product illustrated well-developed BET surface area and porous structure in optimum product which favored its sorptive ability.
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Li, Qiaoling, Quanxing Zheng, Xiaohua Deng, Zhiqiang Yu, Nan Deng, Fei Xing, Xin Chen, et al. "Numerical Simulation of the Burning Process in a King-Size Cigarette Based on Experimentally Derived Reaction Kinetics." Beiträge zur Tabakforschung International/Contributions to Tobacco Research 29, no. 3 (December 1, 2020): 156–79. http://dx.doi.org/10.2478/cttr-2020-0014.
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Summary A comprehensive two-dimensional (2D) mathematical model has been proposed to simulate the burning process of a king-size cigarette. The characteristics of this model are including: 1) the use of kinetic models for the evaporation of water, the pyrolysis of tobacco and the oxidation of char, 2) the application of mathematical relationships between the release amounts of certain products (i.e., “tar” and CO) and different reaction variables (i.e., temperatures and oxygen concentrations), 3) the introduction of mass, heat and momentum transports, 4) the consideration of filtration effects of the cigarette filter on “tar”. These characteristics were expressed in a set of coupled equations that can be solved numerically by FLUENT. The information about the char density field, temperature field, flow velocity field, “tar” and CO density fields and the filtration efficiency could be obtained from the model. This model was validated by comparing the predictions with experimental data on puff number, the temperatures at specific locations, the filtration efficiency and the yields of “tar” and CO under different puff intensities. The calculated results show a good agreement with the experimental data. The predicted puff number was 7.3, and the experimental puff number was 6.8. The standard root mean square error (NRMSE) between the experimental and the predicted temperatures at specific locations is < 18%. The predicted filtration efficiency for “tar” was 46.1%, and the experimentally determined filtration efficiency for nicotine was 44.5%. The maximum relative deviations of the yields of “tar” and CO under different puff intensities were 8.9% and 10.6%, respectively.
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M’sakni, Nour Houda, and Taghreed Alsufyani. "Removal of Cationic Organic Dye from Aqueous Solution by Chemical and Pyrolysis Activated Ulva lactuca." Water 13, no. 9 (April 22, 2021): 1154. http://dx.doi.org/10.3390/w13091154.
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Ulva lactuca has been used to remove many toxic substances from industrial wastewater. In the present study we tried to optimize the efficiency of U. lactuca as an adsorbent of methylene blue (MB) in aqueous solution. U. lactuca was chemically treated with sulfuric acid (UL-H) and sodium hydroxide (UL-OH) and by a slow pyrolysis process (carbonization process) at high temperature T = 600 °C (UL-T) and compared to the nonactive Ulva (UL-NA) and the water insoluble substance (UL-WIS). Several spectroscopic analyses were carried out to detect the biosorption mechanisms of Ulva to remove MB in solution. The effects of different parameters on the adsorption process were studied, i.e., pH (2–10), mass concentration (1–10 g L−1), and contact time (0–120 min). The results showed that the best adsorption of MB by Ulva was at pH = 8, with 5 g L−1 of biomass at 75 min; the best adsorption capacity was 625.0 mg g−1 for UL-OH, which was able to remove more than 89% of MB compared to UL-T, whose removal rate did not exceed 5%. Fourier-transform infrared spectroscopy (FTIR), energy-dispersive X-ray spectroscopy (EDX), and scanning electron microscopy (SEM) indicated the presence of oxygenated functional groups with a highly porous surface. The kinetic studies confirmed that the majority of treatments follow the pseudo-second-order type. The mathematical models showed that Langmuir model is favorable to UL-OH, UL-WIS, and UL-NA. According to the experimental results, the primary treatment for U. lactuca is a promising environmentally friendly method and an economical strategy for removing MB from aqueous solution. This method can help address the growing demand for adsorbents used in environmental protection processes and the resultant increase in their price.
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Raupp, Íris Nunes, Alaor Valério Filho, Aline Lemos Arim, Ana Rosa Costa Muniz, and Gabriela Silveira da Rosa. "Development and Characterization of Activated Carbon from Olive Pomace: Experimental Design, Kinetic and Equilibrium Studies in Nimesulide Adsorption." Materials 14, no. 22 (November 12, 2021): 6820. http://dx.doi.org/10.3390/ma14226820.
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The lack of adequate treatment for the removal of pollutants from domestic, hospital and industrial effluents has caused great environmental concern. Therefore, there is a need to develop materials that have the capacity to treat these effluents. This work aims to develop and characterize an activated charcoal from olive pomace, which is an agro-industrial residue, for adsorption of Nimesulide in liquid effluent and to evaluate the adsorption kinetics and equilibrium using experimental design. The raw material was oven dried at 105 °C for 24 h, ground, chemically activated in a ratio of 1:0.8:0.2 of olive pomace, zinc chloride and calcium hydroxide and thermally activated by pyrolysis in a reactor of stainless steel at 550 °C for 30 min. The activated carbon was characterized by Fourier Transform Infrared (FTIR) spectroscopy, X-ray Diffractometry (XRD), Brunauer, Emmett and Teller (BET) method, Thermogravimetric Analysis (TGA), Scanning Electron Microscopy (SEM), density and zero charge potential analysis. The surface area obtained was 650.9 m2 g−1. The kinetic and isothermal mathematical models that best described the adsorption were PSO and Freundlich and the highest adsorption capacity obtained was 353.27 mg g−1. The results obtained showed the good performance of activated carbon produced from olive pomace as an adsorbent material and demonstrated great potential for removing emerging contaminants such as Nimesulide.
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de Deus, Mirian, Ana Z. Miller, and Nicasio T. Jiménez-Morillo. "Molecular Characterization of Burned Organic Matter at Different Soil Depths and Its Relationship with Soil Water Repellency: A Preliminary Result." Agronomy 11, no. 12 (December 16, 2021): 2560. http://dx.doi.org/10.3390/agronomy11122560.
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Soil water repellency (hydrophobicity) prevents water from wetting or infiltrating soils, triggering changes in the ecosystems. This physical property is directly correlated to the erodibility grade of a soil. Wildfire events may develop, enhance, or destroy soil hydrophobicity, modifying the erodibility grade of a soil and increasing the loss of its most reactive layer (organic matter). To assess the main organic family of compounds (biomarkers) surrogates to fire-induced water repellency, a study was carried out on a fire-affected soil under eucalyptus canopy at two depths (0–2 and 2–5 cm) from Portugal. The potential soil water repellency was measured using the water drop penetration time (WDPT) test. The molecular characterization of hydrophobic biomarkers was carried out using analytical pyrolysis (Py-GC/MS) in combination with multivariate statistical analysis (PCA, MLR). The upper burned soil layer (0–2 cm) displayed a significant contribution of fresh biomass (lignin and polysaccharides), while the deepest (2–5 cm) one showed more humified organic matter (lipids). The soil hydrophobicity was directly correlated to non-polar organic compounds, such as lipids and polycyclic aromatic hydrocarbons (PAHs), and inversely to unspecific aromatic compounds. The combination of mass spectrometry techniques and chemometric analysis allowed obtaining a preliminary forecast model of hydrophobicity degree in fire-affected soil samples under eucalyptus canopy. This analytical approach opens the door to developing more sensitive mathematical models using molecular organic compounds to predict the alteration of hydrophobicity and other soil physical properties induced by fires.
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Andriotis, Eleftherios G., Rigini M. Papi, Adamantini Paraskevopoulou, and Dimitris S. Achilias. "Synthesis of D-Limonene Loaded Polymeric Nanoparticles with Enhanced Antimicrobial Properties for Potential Application in Food Packaging." Nanomaterials 11, no. 1 (January 13, 2021): 191. http://dx.doi.org/10.3390/nano11010191.
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Mini-emulsion polymerization was applied for the synthesis of cross-linked polymeric nanoparticles comprised of methyl methacrylate (MMA) and Triethylene Glycol Dimethacrylate (TEGDMA) copolymers, used as matrix-carriers for hosting D-limonene. D-limonene was selected as a model essential oil, well known for its pleasant odor and its enhanced antimicrobial properties. The synthesized particles were assessed for their morphology and geometric characteristics by Dynamic Light Scattering (DLS) and Scanning Electron Microscopy (SEM), which revealed the formation of particles with mean diameters at the nanoscale (D[3,2] = 0.135 μm), with a spherical shape, while the dried particles formed larger clusters of several microns (D[3,2] = 80.69 μm). The percentage of the loaded D-limonene was quantified by Thermogravimetric Analysis (TGA), complemented by Gas Chromatography-Mass Spectrometry analysis coupled with a pyrolysis unit (Py/GC-MS). The results showed that the volatiles emitted by the nanoparticles were composed mainly of D-limonene (10% w/w of dry particles). Particles subjected to higher temperatures tended to decompose. The mechanism that governs the release of D-limonene from the as-synthesized particles was studied by fitting mathematical models to the release data obtained by isothermal TGA analysis of the dry particles subjected to accelerated conditions. The analysis revealed a two-stage release of the volatiles, one governed by D-limonene release and the other governed by TEGDMA release. Finally, the antimicrobial potency of the D-limonene-loaded particles was demonstrated, indicating the successful synthesis of polymeric nanoparticles loaded with D-limonene, owing to enhanced antimicrobial properties. The overall performance of these nanoparticles renders them a promising candidate material for the formation of self-sterilized surfaces with enhanced antimicrobial activity and potential application in food packaging.
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Valeev, Ilnar A., Irina V. Zhukova, and Azat A. Girfanutdinov. "Mathematical modeling of the process of obtaining raw material for manufacturing sorbents of medical purpose." Butlerov Communications 61, no. 3 (March 31, 2020): 49–58. http://dx.doi.org/10.37952/roi-jbc-01/20-61-3-49.
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This article analyzes the production and use of affordable medical sorbents in the Russian and international markets. The analysis showed that there is a shortage of production of cheap specific activated carbon in Russia, due to insufficient expansion of the range. Today, the price of coal tends to increase, so many manufacturers are puzzled by the creation of an effective system for processing coal. It was suggested to use burnt charcoal from various types of wood, since it is one of the optimal types of sorbents, taking into account the economic aspect and the naturalness of the raw materials used for the production of activated carbon. An efficient and simple method of processing burnt coal-pyrolysis-was also proposed. Verification of the model's adequacy to the real process was performed by comparing the results of experimental studies with the results of theoretical calculations. The basic kinetic and thermophysical equations that are used today to study the kinetics of pyrolysis of activated carbon are studied. To find out whether a change in pressure can affect the course of the pyrolysis process, an experimental setup was developed and a series of experiments were conducted. Wood samples were used for experiments. 25x25x25 mm and humidity 10%. The volume of one-time loading was 50 g. The operating pressure in the pyrolysis chamber was recorded by a pressure gauge and set using ejector pumps (pressure reducers), whose performance was regulated and was 0.9, 0.8, 0.7, 0.6, 0.5 kPa, or a nitrogen cylinder (pressure increase) to the absolute pressure values 1, 2, 3, 4, 5, 6 kPa.A comparative analysis of mathematical calculations and a number of experimental data conducted on warty birch was also carried out. A mathematical model of the wood pyrolysis process is proposed, which takes into account pre-drying, kinetics, the amount of volatile products released, and cooling of the finished charcoal.
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Cordiner, Stefano, Alessandro Manni, Vincenzo Mulone, and Vittorio Rocco. "Biomass pyrolysis modeling of systems at laboratory scale with experimental validation." International Journal of Numerical Methods for Heat & Fluid Flow 28, no. 2 (February 5, 2018): 413–38. http://dx.doi.org/10.1108/hff-11-2016-0459.
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Purpose Thermochemical conversion processes are one of the possible solutions for the flexible production of electric and thermal power from biomass. The pyrolysis degradation process presents, among the others, the interesting features of biofuels and high energy density bio-oil production potential high conversion rate. In this paper, numerical results of a slow batch and continuous fast pyrolyzers, are presented, aiming at validating both a tridimensional computational fluid dynamics-discrete element method (CFD–DEM) and a monodimensional distributed activation energy model (DAEM) represents with data collected in dedicated experiments. The purpose of this paper is then to provide reliable models for industrial scale-up and direct design purposes. Design/methodology/approach The slow pyrolysis experimental system, a batch of small-scale constant-pressure bomb for allothermic conversion processes, is presented. A DEM numerical model has been implemented by means of a modified OpenFOAM solver. The fast pyrolysis experimental system and a lab scale screw reactor designed for biomass fast pyrolysis conversion are also presented along with a 1D numerical model to represent its operation. The model which is developed for continuous stationary feeding conditions and based on a four-parallel reaction chemical framework is presented in detail. Findings The slow pyrolysis numerical results are compared with experimental data in terms of both gaseous species production and reduction of the bed height showing good predictive capabilities. Fast pyrolysis numerical results have been compared to the experimental data obtained from the fast pyrolysis process of spruce wood pellet. The comparison shows that the chemical reaction modeling based on a Gaussian DAEM is capable of giving results in very good agreement with the bio-oil yield evaluated experimentally. Originality/value As general results of the proposed activities, a mixed experimental and numerical approach has demonstrated a very good potential in developing design tools for pyrolysis development.
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Marsden, Barry, Andrew Mummery, and Paul Mummery. "Modelling the coefficient of thermal expansion in graphite crystals: implications of lattice strain due to irradiation and pressure." Proceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences 474, no. 2218 (October 2018): 20180075. http://dx.doi.org/10.1098/rspa.2018.0075.
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Theoretical models for the coefficient of thermal expansion (CTE) first proposed in the 1970s are expanded upon, allowing them, for the first time, to be implemented over a wide temperature range. The models are of interest because they predict the effects of the changes in the crystal lattice spacing and crystallite modulus on the CTE. Hence, they can in turn be used to investigate the influence of pressure and irradiation on the CTE. To date, typographical and mathematical errors and incomplete or conflicting assumptions between the various papers had made the complex mathematical formulations difficult, if not impossible, to follow and apply. This paper has two main aims: firstly to revisit and review the CTE models, correcting the errors and compiling and updating various input data, secondly to use the revised models to investigate the effect of loading and irradiation on the CTE. In particular, the models have been applied to data for natural and highly orientated pyrolytic graphite and compared with experimental data, giving an insight into the influence of temperature, loading and irradiation on both single crystal and polycrystalline graphite. The findings lend credence to postulated microstructural mechanisms attributed to the in-reactor behaviour of nuclear graphite, which finds a wide use in predictive multiscale modelling.
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Rammohan, Draksharapu, Nanda Kishore, and Ramgopal V. S. Uppaluri. "Kinetics and thermodynamics investigation of pyrolysis of butyl rubber tube waste." European Journal of Sustainable Development Research 7, no. 2 (April 1, 2023): em0215. http://dx.doi.org/10.29333/ejosdr/12878.
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Pyrolysis of butyl rubber tube waste was performed under an inert nitrogen gas environment for temperature ranging between 25 and 1,000 °C, by varying the heating rates (5, 10, 20, 35, and 55 °C min<sup>−1</sup>). Five different iso-conversional approaches, namely, Differential Friedman, Ozawa-Flynn-Wall, Kissinger-Akahira-Sunuse, Distributed activation, and Starink, were employed to investigate the kinetics and thermodynamic parameters. The mean activation energy (<i>E</i><i><sub>α</sub></i>), and pre-exponential factor (<i>k<sub>o</sub></i>) varied between 222.67 and 244.73 kJ mol<sup>-1</sup> and 6.82×10<sup>21</sup> and 2.73×10<sup>24</sup> s<sup>-1 </sup>respectively, for all iso-conversional approaches. From the kinetic investigation, a strong correlation co-efficient (R<sup>2</sup>>0.97) was ascertained in the conversion range of up to α=0.8 for all the iso-conversational approaches. By thermodynamic analysis, the mean values of change in enthalpy and change in Gibbs free energy were 217.06-239.13 kJ mol<sup>-1 </sup>and 185.12-218.11, kJ mol<sup>-1</sup>, respectively. From the master plot analysis, diffusion model (D3), and several reaction order models (F1, F2, F3, and F5) were predicted throughout the conversion (0.1 to 0.8) limit at 20 °C min<sup>-1</sup> for the pyrolysis of BRT.
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Kothari, Mrityunjay, Moon-Hyun Cha, Victor Lefevre, and Kyung-Suk Kim. "Critical curvature localization in graphene. II. Non-local flexoelectricity–dielectricity coupling." Proceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences 475, no. 2221 (January 2019): 20180671. http://dx.doi.org/10.1098/rspa.2018.0671.
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As a sequel of part I (Kothari et al. 2018 Proc. R. Soc. A 474 , 20180054), we present a general thermodynamic framework of flexoelectric constitutive laws for multi-layered graphene (MLG), and apply these laws to explain the role of crinkles in peculiar molecular adsorption characteristics of highly oriented pyrolytic graphite (HOPG) surfaces. The thermodynamically consistent constitutive laws lead to a non-local interaction model of polarization induced by electromechanical deformation with flexoelectricity–dielectricity coupling. The non-local model predicts curvature and polarization localization along crinkle valleys and ridges very close to those calculated by density functional theory (DFT). Our analysis reveals that the non-local model can be reduced to a simplified uc-local or e-local model (Kothari et al. 2018 Proc. R. Soc. A 474 , 20180054) only when the curvature distribution is uniform or highly localized. For the non-local model, we calibrated and formulated the layer-number-dependent dielectric and intrinsic flexoelectric coefficients of MLGs. In addition, we also obtained layer-number dependent flexoelectric coefficients for uc-local and e-local models. Our DFT analysis shows that polarization-induced adsorption of neutral molecules at crinkle ridges depends on the molecular weight of the molecule. Furthermore, our detailed study of polarization localization in graphene crinkles enables us to understand previously unexplained self-organized adsorption of C 60 buckyballs in a linear array on an HOPG surface.
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Miljkovic, Biljana. "Effect of Operating Parameters on Agricultural Biomass Mixture Pyrolysis Process in a Batch Reactor." Periodica Polytechnica Chemical Engineering, January 9, 2023. http://dx.doi.org/10.3311/ppch.20257.
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Many phenomena affect devolatilization of biomass particles, including mass and heat transfer, chemical reactions and physical transformation. Mathematical models that are capable to describe pyrolysis phenomena can greatly assist the large-scale development and optimization of pyrolysis processes, but to be implemented into large-scale simulation the models need to be simplified at a certain degree. In the present study, an existing mathematical model is used to describe the pyrolysis of a single particle of biomass. It couples the heat transfer equations with the chemical kinetics equations. The common Euler explicit method is used for solving the heat transfer equation and the two-step pyrolysis kinetics equations. The model equation is solved for a sphere particle with a radius of 0.001 m and temperature ranging from 300 to 923 K. An original numerical model for the pyrolysis of agricultural biomass mixture is proposed and relevant equations solved using original program realized in MATLAB. Simplified particle model was validated with the experimental data in a non-isothermal pyrolysis reactor. The sample was heated in the temperature range of 300–923 K at average heating rates of 21, 30 and 54 K/min. The model results showed reasonable agreement with experiments. The difference (between the experimental and model results) is slightly more prominent with decreasing heating rate (21 and 30 K/min), but model results are in much better agreement with the experimental date for higher heating rate (54 K/min). It is demonstrated that a constitutive equation can be used to express devolatilization rate for higher heating rates.
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Kondratenko, Yurii P., Oleksii V. Kozlov, and Oleksii V. Korobko. "Development of intelligent controllers for pyrolysis reactors control systems based on their mathematical models." Collection of Scientific Publications NUS, no. 6 (January 16, 2015). http://dx.doi.org/10.15589/jnn20140611.
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Şerbănescu, Cristina. "Kinetic analysis of cellulose pyrolysis: a short review." Chemical Papers 68, no. 7 (January 1, 2014). http://dx.doi.org/10.2478/s11696-013-0529-z.
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AbstractSince the 1950s, cellulose pyrolysis has been the subject of intense study, with kinetic analyses forming a major part of these studies. They represent useful tools for a better understanding of the physicochemical process and for the proper design of industrial pyrolysis units. Until recently, the methods most frequently used in these analyses were based on model-fitting, i.e. the fitting of the experimental data to a number of mathematical models. Nowadays, other methods, so-called “model-free” methods, are considered to be more suited. These are based on the principle that, at constant conversion, the reaction rate depends only on temperature. In its first part, this short review presents the particularities and drawbacks of the traditional model-fitting models. Subsequently, several main contributions in this field are listed and discussed. Finally, the more suited “model-free” (isoconversional) methods are explained and several main studies presented, as well as a comparison of this method with the model-fitting ones.
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Singh, Kaushlendra, Mark Risse, K. C. Das, and John Worley. "Determination of Composition of Cellulose and Lignin Mixtures Using Thermogravimetric Analysis." Journal of Energy Resources Technology 131, no. 2 (May 19, 2009). http://dx.doi.org/10.1115/1.3120349.
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The proportional composition of cellulose, hemicellulose, lignin, and minerals in a biomass plays a significant role in the proportion of pyrolysis products (bio-oil, char, and gases). Traditionally, the composition of biomass is chemically determined, which is a time consuming process. This paper presents the results of a preliminary investigation of a method using thermogravimetric analysis for predicting the fraction of cellulose and lignin in lignin-cellulose mixtures. The concept is based on a newly developed theory of pyrolytic unit thermographs (PUTs). The PUT is a thermograph showing rate of change in biomass weight with respect to temperature for a unit weight loss. These PUTs were used as input for two predictive mathematical procedures that minimize noise to predict the fractional composition in unknown lignin-cellulose mixtures. The first model used linear correlations between cellulose/lignin content and peak decomposition rate while the second method used a system of linear equations. Results showed that both models predicted the composition of lignin-cellulose mixture within 7–18% of measured value. The promising results of this preliminary study will certainly motivate further refinement of this method through advanced research.
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Bhat, Vinay S., Titilope John Jayeoye, Thitima Rujiralai, Uraiwan Sirimahachai, Kwok Feng Chong, and Gurumurthy Hegde. "Acacia auriculiformis–Derived Bimodal Porous Nanocarbons via Self-Activation for High-Performance Supercapacitors." Frontiers in Energy Research 9 (September 23, 2021). http://dx.doi.org/10.3389/fenrg.2021.744133.
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Carbon nanomaterials derived from Acacia auriculiformis pods as electrodes for the electrochemical double-layer capacitors were explored. Four pyrolysis temperatures were set (400, 600, 800, and 1,000°C) to understand the role of temperature in biomass pyrolysis via a possible “self-activation” mechanism for the synthesis of carbon materials. The carbon materials synthesized at 800°C (AAC800) were found to exhibit a well-organized hierarchical porous structure, quantified further from N2 adsorption/desorption isotherms with a maximum specific surface area of 736.6 m2/g. Micropores were found to be contributing toward enhancing the specific surface area. AAC800 exhibited a maximum specific capacitance of 176.7 F/g at 0.5 A/g in 6.0 M KOH electrolyte in a three-electrode setup. A symmetric supercapacitor was fabricated using AAC800 as an active material in an organic electrolyte composed of 1.0 M tetraethylammonium tetrafluoroborate (TEABF4) as a conducting salt in the acetonitrile (ACN) solvent. The self-discharge of the cell/device was analyzed from fitting two different mathematical models; the cell also exhibited a remarkable coulombic efficiency of 100% over 10,000 charge/discharge cycles, retaining ∼93% capacitance at 2.3 V.
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Haydary, Juma, and Dalibor Susa. "Kinetics of thermal decomposition of aseptic packages." Chemical Papers 67, no. 12 (January 1, 2013). http://dx.doi.org/10.2478/s11696-013-0319-7.
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AbstractKinetics of thermal decomposition of aseptic packages (e.g. Tetrapak cartons) and pyrolysis of this waste in a laboratory flow reactor was studied. Three different models for the calculation of the reaction rate and the determination of apparent kinetic parameters of thermal decomposition were used. The first method assumes a two stage thermal decomposition and the kinetic parameters were determined by fitting a derivative thermogravimetric (DTG) curve to experimentally determined thermogravimetric data of whole aseptic cartons. The second method uses kinetic parameters determined by fitting DTG curves to thermogravimetric data of individual components of aseptic packages. The last method was a multi-curve isoconversion method assuming a change of kinetic parameters with the increasing conversion. All types of the determined kinetic parameters were used in a mathematical model for thermal decomposition of mini briquettes made from aseptic packages at the temperature of 650°C. The model calculated also the heat conduction in the particles and it was verified by an independent set of experiments conducted in a laboratory screw type flow reactor.
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Puchongkawarin, Channarong, and Supatpong Mattaraj. "Development of a superstructure optimization framework for the design of municipal solid waste facilities." Sustainable Environment Research 30, no. 1 (November 18, 2020). http://dx.doi.org/10.1186/s42834-020-00071-7.
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AbstractThe main objective of this study is to develop a decision-making tool for the design of the optimal municipal solid waste (MSW) facilities based on superstructure optimization. Currently, the disposal of MSW is a major problem due to the lack of awareness of the negative impacts resulting from dumping MSW into the environment. This poses a challenge for the authorities. MSW valorization such as anaerobic digestion, pyrolysis, and gasification has been increasingly focused on as an approach when handling MSW to enhance both economic and environmental sustainability. However, with an increasing array of processing technologies, the design of MSW facilities involving the integration of these technologies is becoming tedious and unmanageable. To deal with this problem, superstructure optimization is proposed. It is an effective tool for the design of several chemical processes because it is able to consider all potential process alternatives including the optimal solution using mathematical models based on mass and energy balances. Uncertainty is incorporated into the optimization framework to enhance the robustness of the solution. The proposed methodology was applied in the design process of the MSW facility in Ubon Rathathani Province, Thailand, with the objective function of maximizing the profit. The optimization problem was developed as Mixed Integer Linear Programming and it was solved using an optimization platform, General Algebraic Modeling System, with CPLEX as the solver related to obtaining the optimal solution. The results show there to be as positive profit that is economically viable compared to the use of landfill technology.
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Li, Yong, Yingchun Zhang, Gongnan Xie, and Bengt Ake Sunden. "Research status of supercritical aviation kerosene and a convection heat transfer considering thermal pyrolysis." International Journal of Numerical Methods for Heat & Fluid Flow, January 21, 2022. http://dx.doi.org/10.1108/hff-08-2021-0579.
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Purpose This paper aims to comprehensively clarify the research status of thermal transport of supercritical aviation kerosene, with particular interests in the effect of cracking on heat transfer. Design/methodology/approach A brief review of current research on supercritical aviation kerosene is presented in views of the surrogate model of hydrocarbon fuels, chemical cracking mechanism of hydrocarbon fuels, thermo-physical properties of hydrocarbon fuels, turbulence models, flow characteristics and thermal performances, which indicates that more efforts need to be directed into these topics. Therefore, supercritical thermal transport of n-decane is then computationally investigated in the condition of thermal pyrolysis, while the ASPEN HYSYS gives the properties of n-decane and pyrolysis products. In addition, the one-step chemical cracking mechanism and SST k-ω turbulence model are applied with relatively high precision. Findings The existing surrogate models of aviation kerosene are limited to a specific scope of application and their thermo-physical properties deviate from the experimental data. The turbulence models used to implement numerical simulation should be studied to further improve the prediction accuracy. The thermal-induced acceleration is driven by the drastic density change, which is caused by the production of small molecules. The wall temperature of the combustion chamber can be effectively reduced by this behavior, i.e. the phenomenon of heat transfer deterioration can be attenuated or suppressed by thermal pyrolysis. Originality/value The issues in numerical studies of supercritical aviation kerosene are clearly revealed, and the conjugation mechanism between thermal pyrolysis and convective heat transfer is initially presented.
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Frankel, Ari, Ellen Wagman, Ryan Keedy, Brent Houchens, and Sarah N. Scott. "Embedded-Error Bayesian Calibration of Thermal Decomposition of Organic Materials." Journal of Verification, Validation and Uncertainty Quantification 6, no. 4 (August 12, 2021). http://dx.doi.org/10.1115/1.4051638.
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Abstract Organic materials are an attractive choice for structural components due to their light weight and versatility. However, because they decompose at low temperatures relative to traditional materials, they pose a safety risk due to fire and loss of structural integrity. To quantify this risk, analysts use chemical kinetics models to describe the material pyrolysis and oxidation using thermogravimetric analysis (TGA). This process requires the calibration of many model parameters to closely match experimental data. Previous efforts in this field have largely been limited to finding a single best-fit set of parameters even though the experimental data may be very noisy. Furthermore, the chemical kinetics models are often simplified representations of the true decomposition process. The simplification induces model-form errors that the fitting process cannot capture. In this work, we propose a methodology for calibrating decomposition models to TGA data that accounts for uncertainty in the model-form and experimental data simultaneously. The methodology is applied to the decomposition of a carbon fiber epoxy composite with a three-stage reaction network and Arrhenius kinetics. The results show a good overlap between the model predictions and TGA data. Uncertainty bounds capture deviations of the model from the data. The calibrated parameter distributions are also presented. The distributions may be used in forward propagation of uncertainty in models that leverage this material.