scholarly journals Modeling of kinetics of drying process of polycaproamide granules considering its sorption properties

2018 ◽  
Author(s):  
Marina Sergeevna Maklusova ◽  
Maria Konstantinovna Kosheleva ◽  
Olga Roaldovna Dornyak
Keyword(s):  
Mathematical Modeling ◽  
Mathematical Model ◽  
Mass Transfer ◽  
Moisture Content ◽  
Gas Phase ◽  
Heat And Mass Transfer ◽  
Sorption Properties ◽  
Convective Drying ◽  
Drying Process ◽  
Kinetics Of

The object of research is a fiber-forming polymer - polycaproamide. The process of drying of polycaproamide granules, after aqueous extraction of low-molecular compounds from them, is an important stage of producing of polyamide fiber nylon and largely determines the quality of the target product. To obtain a high-quality fiber, the drying of the granules should provide a sufficiently high degree of its dehydration. The average final moisture content of the material should be no more than 0.1%. With a low moisture content, the drying process slows down, so the calculation of the kinetics of dewatering of granules can not be carried out using a constant effective mass-transfer coefficient (moisture diffusion). In this paper we present a calculation technique for determining two local parameters of mass transfer: the water diffusion coefficient in polycaproamide (as a liquid) and the so-called criterion for phase transitions, which depend on the moisture content of the material and are determined by its sorption properties. The report presents the results of numerical calculations illustrating the development of two-dimensional fields of moisture content, temperature, pressure and vapor concentration in the vapor-gas phase for cylindrical granules in convective drying. To describe the processes of heat and mass transfer during the drying of granules, a nonstationary nonlinear 2D model is used that includes transport equations averaged over the microvolume of the material: the liquid phase transfer equation; heat equation; equation for vapor-gas phase pressure; equation for the concentration of the vapor component. The nonstationary nonlinear conjugate mathematical model is studied numerically. A feature of the presented model is the possibility of an analytical calculation of the local mass transfer coefficients of a liquid, taking into account the sorption properties of the material, the permeability coefficient and the local values ​​of humidity and temperature. Determination of the local coefficients of moisture transfer is carried out on the basis of the formulas obtained in the analysis of a more general mathematical model of heat and mass transfer carried out based on the mechanics of multiphase systems developed in the works of R.I. Nigmatulin, and S. Whitaker. The structure of the samples was investigated by three independent methods in order to obtain the most complete idea of ​​it and to compare the obtained characteristics. The isotherms of the sorption of polycaproamide were obtained experimentally on a vacuum sorption plant with Mac-Ben-Bakr weights. Comparison of the results of mathematical modeling of heat and mass transfer in the granule and data of the laboratory experiment on the kinetics of polycaproamide granule drying showed good agreement between the calculated and experimental data. The constructed mathematical model allows to form energy-efficient resource-saving regimes for drying granules of polycaproamide.Keywords: convective drying, mathematical modeling, polycaproamide.

Thermodynamic Theory of Convective Drying Process of Porous Media

2002 ◽  
Author(s):  
You-Rong Li ◽  
Dan-Ling Zeng
Keyword(s):  
Mass Transfer ◽  
Heat Source ◽  
Heat And Mass Transfer ◽  
Internal Heat ◽  
Internal Heat Source ◽  
Thermodynamic Theory ◽  
Convective Drying ◽  
Internal Mass ◽  
Drying Process ◽  
Mass Source

Based on non-equilibrium thermodynamic theory and combined with the conservation laws, a comprehensive theoretical model was established to describe heat and mass transfer during convective drying process, and numerical calculation was performed. The results show that: (a) the external convective heat and mass transfer may be treated as the conductive heat transfer with internal heat source and the molecular mass diffusion with internal mass source, respectively, and the ability of heat and mass transfer mainly depends on the strength of the heat source and mass source; the higher the temperature of the drying media, the lower the strength of the internal heat source, but the higher that of the internal mass sources; (b) the evaporation of internal water takes place inside the whole material, and the molecular mass diffusion of the internal vapor is in the direction of decreasing mass transfer potential, not along the decreasing partial pressure of vapor.

scholarly journals 3D simulation on convective drying process for cylindrical tea particle using CFD software to analyze the heat and mass transfer phenomena

2020 ◽  
Author(s):  
Eflita Yohana ◽  
Nazaruddin Sinaga ◽  
Haryo Pachusadewo ◽  
M. Irfan Nugraha ◽  
M. Endy Yulianto ◽  
...  
Keyword(s):  
Mass Transfer ◽  
Heat And Mass Transfer ◽  
3D Simulation ◽  
Convective Drying ◽  
Drying Process

Heat and Mass Transfer during Contact Drying in a Laundry Calender

1973 ◽  
Vol 187 (1) ◽  
pp. 591-599
Author(s):  
J. F. T. MacLaren ◽  
A. A. Nicol ◽  
R. Wallace
Keyword(s):  
Mass Transfer ◽  
Moisture Content ◽  
Heat And Mass Transfer ◽  
Initial Moisture Content ◽  
Temperature Profiles ◽  
Drying Process ◽  
Steam Temperature ◽  
Empirical Expression ◽  
Contact Drying ◽  
Physical Variables

Contact drying of fabric was studied using a two-roll steam-heated laundry calender. The effects on heat and mass transfer of steam temperature, fabric initial moisture content, fabric velocity, contact pressure and steam-side heat transfer coefficient were observed experimentally. Bed and roller surface temperature profiles were measured to assist in interpreting and subsequently analysing the drying process. The experimental results were correlated using dimensionless parameters derived from a dimensional analysis of a drying equation. An empirical expression was obtained that related the final moisture content of the fabric to the initial moisture content and the other pertinent physical variables.

Heat and Mass Transfer Analysis of Fabric in the Tenter Frame

1997 ◽  
Vol 67 (5) ◽  
pp. 311-316 ◽  
Author(s):  
Sang Il Park ◽  
Doo Hyun Baik
Keyword(s):  
Mathematical Model ◽  
Mass Transfer ◽  
Finite Difference Method ◽  
Moisture Content ◽  
Heat And Mass Transfer ◽  
Initial Moisture Content ◽  
Transfer Coefficients ◽  
Operation Parameters ◽  
The Finite Difference Method ◽  
Experimental Values

A mathematical model is developed for heat and mass transfer analysis of fabric in the tenter frame. Using the model, the calculated transient fabric temperatures in the tenter frame agree well with the experimental values measured by Beard. Variations in temperature and moisture content distribution are solved using the finite-difference method. The effects of operation parameters, such as temperature and humidity in the tenter, initial moisture content of the fabric, and heat and mass transfer coefficients, are examined using the model.

scholarly journals RESEARCH OF HEAT AND MASS TRANSFER DURING CONVECTIVE DRYING OF COLLOID CAPILLARY-POROUS MATERIALS

2020 ◽  
Author(s):  
Kateryna Slobodianiuk ◽  
◽  
Kateryna Samoilenko ◽  
Keyword(s):  
Mass Transfer ◽  
Porous Materials ◽  
Heat And Mass Transfer ◽  
Raw Materials ◽  
Biochemical Properties ◽  
The Body ◽  
Biologically Active ◽  
Convective Drying ◽  
Drying Process ◽  
Vegetable Raw Materials

The article presents a reasonable analysis and relevance of the study of the drying process of vegetable raw materials (colloidal capillary-porous materials). Drying is an energy-intensive industrial process that is defined from a technological point of view: on the one hand by heat and moisture exchange between the body surface and the environment, on the other hand by heating the body and transferring moisture inside it due to the form of moisture. One of the most effective ways to increase the shelf life of food is to dry it to equilibrium humidity. Very important are the technological parameters of the drying regimes, which, when used rationally, are able to preserve the biochemical properties and nutrients of the raw material at a high level in the obtained dry product. The study of dehydration of vegetable raw materials is widely practiced around the world, especially in countries such as Germany, France, USA, Argentina, Hungary, Brazil, Poland, Korea, China, Malaysia. However, the obtained processed products lose their biologically active components and nutrients, and the processing process is energy consuming. Therefore, the problem is relevant and needs an effective solution. In this paper, the kinetics of the drying process, thermogravimetric studies and a mathematical model for colloidal capillary-porous materials of plant origin were analyzed. According to the results of the highlighted research, the process of convective drying of colloidal capillary-porous materials was intensified above 21% due to the use of innovative step regimes. The developed beet-rhubarb composition is a colloidal capillary-porous material that stabilizes and protects at the biochemical level betanin of the beet from the effects of temperature during convective drying, has in comparison with the components of the composition lower heat of dehydration and increased thermal-stability. Prolonged high-temperature exposure causes instant complete destruction of sugars, proteins and other nutrients components. Derivatographic studies have confirmed that the use of the temperature range of 100 ° C in a stepwise mode of 100/60 ° C for the developed soybean-spinach composition is safe for biologically active substances and it is justified by experimental temperature curves. Numerical modeling of heat and mass transfer during convective drying of crushed beets and crushed soybeans using the known model by A.V. Lykov satisfactorily describes the process and can be used to model the convection drying of colloidal capillary-porous materials.

scholarly journals Mathematical Modeling of the Process of Micro Irrigation in the Soil Layer under Conditions of Heat and Mass Transfer

2019 ◽  
pp. 84-85
Author(s):  
Anatolii Vlasyuk ◽  
Viktor Ogiychuk
Keyword(s):  
Mathematical Modeling ◽  
Mathematical Model ◽  
Mass Transfer ◽  
Boundary Value Problem ◽  
Heat And Mass Transfer ◽  
Finite Differences ◽  
Numerical Experiments ◽  
Soil Layer ◽  
Nonlinear Mathematical Model ◽  
Micro Irrigation

The nonlinear mathematical model of a process micro irrigation in non-saturated of soil layer under of heat and mass transfer has presented. The numerical solution of the espective boundary value problem has obtained by the method of finite differences using the monotonic scheme. Software had created on the basic of developed algorithms and a series of numerical experiments were done.

scholarly journals МАТЕМАТИЧЕСКАЯ МОДЕЛЬ И МЕТОД РАСЧЕТА ДИНАМИКИ СУШКИ И ТЕРМОДЕСТРУКЦИИ БИОМАССЫ

2018 ◽  
Vol 82 (1) ◽  
Author(s):  
Наталья Николаевна Сороковая ◽  
Дмитрий Николаевич Коринчук
Keyword(s):  
Mathematical Model ◽  
Mass Transfer ◽  
Thermal Decomposition ◽  
Numerical Method ◽  
Heat And Mass Transfer ◽  
The Body ◽  
Physical Factors ◽  
Deformation Equation ◽  
The Mathematical Model ◽  
Kinetics Of

Разработана математическая модель и численный метод расчета динамики тепломассопереноса, фазовых превращений и усадки при сушке коллоидных капиллярно-пористых тел цилиндрической формы в условиях равномерного обдува теплоносителем. Математическая модель строилась на базе дифференциального уравнения переноса субстанции (энергии, массы, импульса) в деформируемых системах. Проведены экспериментальные исследования кинетики обезвоживания частиц энергетической вербы в потоке воздуха с целью верификации математической модели. Обоснована возможность ее использования для расчета совместных процессов сушки и начального этапа термического разложения биомассы. С использованием ранее полученных данных по значениям энергии активации Аэф(Т) для различных видов биомассы проведено математическое моделирование динамики и кинетики высокотемпературной сушки в потоке дымовых газов энергетической вербы, которая сопровождается термодеструкцией гемиоцеллюлозы. Результаты численных экспериментов свидетельствуют об адекватности предложенного подхода, эффективности математической модели и метода ее реализации. На их основе возможно проводить исследование динамики тепломассопереноса при сушке частиц различных видов измельченной биомассы; определение температуры начала и окончания первой стадии термического разложения; момента достижения равновесного влагосодержания в зависимости от свойств материала и сушильного агента. Эти данные позволяют выбирать оптимальные с точки зрения сохранения энергии и качества высушиваемого продукта  режимные параметры процесса.         A mathematical model and a numerical method for calculating the dynamics of heat and mass transfer, phase transformations and shrinkage during the drying of colloidal capillary-porous cylindrical bodies under conditions of equitable winding by a coolant are developed. The mathematical model was based on the differential equation of substance (energy, mass, impulse) transfer in deformable systems. It includes the equations diffusion-filtration transfer of energy for the system as a whole, and the mass transfer of the liquid, vapor and air phases in the pores of the body. Expressions for the intensity of evaporation of a liquid, capillary pressure, and the diffusion coefficients are presented. The relative volume strain was found by means of an analytical solution of the thermoconcentration deformation equation. Based on the explicit three-layer counting difference scheme and the procedure splitting of algorithm  by physical factors, a numerical method for realizing this mathematical model is developed.Experimental studies of the kinetics of dehydration of energy willow particles in the airflow were carried out to verify the mathematical model. Its applicability for calculating combined processes of drying and of the initial stage of thermal decomposition of biomass is substantiated. Using the previously obtained data on the activation energy values for various types of biomass, a mathematical simulation of the dynamics and kinetics of high-temperature drying in the flue gas flow of energy willow was carried out, which is accompanied by thermal destruction of hemiocellulose. The results of numerical experiments indicate the adequacy of the proposed approach, the effectiveness of the mathematical model and the method of its implementation. On their basis, it is possible to study the dynamics of heat and mass transfer when drying particles of different types of ground biomass; determination of the temperature of the beginning and ending of the first stage of thermal decomposition; the moment when the equilibrium moisture content is reached, depending on the properties of the material and the drying agent. These data allow choosing the process parameters that are optimal in terms of energy saving and quality of the dried product.

scholarly journals Simulation and Analysis of Plug Flow Fluidized Bed Dryer

2020 ◽  
Vol 9 (7) ◽  
pp. 805-811
Keyword(s):  
Mass Transfer ◽  
Moisture Content ◽  
Heat And Mass Transfer ◽  
Fluidized Bed ◽  
Plug Flow ◽  
Small Scale ◽  
Outlet Temperature ◽  
Drying Process ◽  
Fluidized Bed Dryer ◽  
Hot Air

Today many industries now use the dryer as a part of grain-drying process even during wet and dry seasons. This helps in reducing spoilage and wastage of paddy. Mostly the available industrial dryers are expensive to purchase and to maintain its smooth functioning. This study therefore is a step to design a simple Plug flow fluidized dryer that can lead to introduce small scale dryers to paddy process industry. The Plug flow fluidized bed dryers are designed and fabricated in this study consists of the drying chamber, hot air distributer plate, hot air inlet and exit system, paddy entry and exit system, fluidization chamber unit with temperature control unit and the centrifugal fan. The evaluation of dryer is based on drying time and reduction in moisture content and outlet temperature of paddy on quality parameters. Dryer dimensions are very important to analyze heat and mass transfer analysis of the Plug flow fluidized bed drying process of paddy grains. It was found d that heat and mass transfer properties of paddy grains in fluidized bed dryer was decreases as the time of drying passes and very rapid at the start of drying. The model present here predicts about dryer dimensions along safe zone of rough rice moisture content with other parameters. Simulation results show a good agreement between the simulation model and the existing simulation models

scholarly journals System Model of Heat and Mass Transfer Process for Mobile Solvent Vapor Phase Drying Equipment

2014 ◽  
Vol 2014 ◽  
pp. 1-11 ◽  
Author(s):  
Shiwei Zhang ◽  
Yufang Zhu ◽  
Baozhen Qiao ◽  
Zhijun Zhang
Keyword(s):  
Mathematical Model ◽  
Mass Transfer ◽  
Heat And Mass Transfer ◽  
Technological Process ◽  
Vapor Phase ◽  
Power Transformer ◽  
Water Yield ◽  
Drying Process ◽  
Solvent Vapor ◽  
Theoretical Simulation

The solvent vapor phase drying process is one of the most important processes during the production and maintenance for large oil-immersed power transformer. In this paper, the working principle, system composition, and technological process of mobile solvent vapor phase drying (MVPD) equipment for transformer are introduced in detail. On the basis of necessary simplification and assumption for MVPD equipment and process, a heat and mass transfer mathematical model including 40 mathematical equations is established, which represents completely thermodynamics laws of phase change and transport process of solvent, water, and air in MVPD technological processes and describes in detail the quantitative relationship among important physical quantities such as temperature, pressure, and flux in key equipment units and process. Taking a practical field drying process of 500 KV/750 MVA power transformer as an example, the simulation calculation of a complete technological process is carried out by programming with MATLAB software and some relation curves of key process parameters changing with time are obtained such as body temperature, tank pressure, and water yield. The change trend of theoretical simulation results is very consistent with the actual production record data which verifies the correctness of mathematical model established.

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