scholarly journals PROBLEMATICS OF CONSTRUCTION OF MATHEMATICAL MODELS OF THE PROCESS OF MICROWAVE DRYING OF SOY

Author(s):  
Valentyna Bandura ◽  
Oleksandr Popiak

The article reviews various techniques for mathematical modeling of the soybean drying process. The purpose of this paper is to review, analyze and compare existing approaches to mathematically describe the processes of moisture movement during microwave drying of soybeans. The only way to provide mathematical modeling of the processes occurring in the soybean grain is a combination of the transformation of microwave energy into heat, the heating of dipole water molecules existing in the seed, the processes of moving moisture from the center to the grain shell and evaporation of moisture. Today, microwave drying is one of the promising areas for research, because this method is much more efficient than traditional post-harvest grain drying methods and, at the same time, poorly understood. Factors on which the process of microwave drying depends on are the speed of movement of moisture in the micropores of the product, the initial temperature and humidity of the raw material, the placement of the main magnetron relative to the object of drying and the speed of movement of raw materials in the drying chamber. The object of the study in this article was to simplify the mathematical model of soybean seeds. To intensify the process of microwave drying, it is advisable to use a combined effect, such as blowing, which increases the intensity and quality of the process of microwave dehumidification. In addition, in this case, the simultaneous use of two or more factors of influence, which allows for rapid processing of raw materials. This determines the relevance and prospects of this study. The developed criteria criterion is substantiated and described, which allows to simplify the complex calculation of microwave energy transfer processes, sample heating and moisture velocity in it. The basic approaches to the construction of a mathematical model of the soybean drying process are considered, and their expediency is determined. The analysis of various methods of mathematical description of the drying process is carried out, the main disadvantages of these methods are identified. It is established that drying soybean seeds in the microwave field is one of the most promising. A mathematical model for a combined soybean drying process with a combination of microwave drying methods and air blowing is proposed.

2020 ◽  
Author(s):  
Gennady Alekseev ◽  
Olga Egorova ◽  
Aleksey Egorov

The article describes a more environmentally friendly method to produce pectin compared to the classical acid scheme, which requires the use of strong mineral acids and toxic solvents. This method of obtaining pectin, like other analogs of the classical method, causes a decrease in the yield of the final product. This study aims to find ways of eliminating these barriers and increase the yield of pectin. The paper investigates the possibility to increase the yield of pectin obtained by acid hydrolysis applying citric acid through the use of preliminary microwave exposure to citrus raw materials. The work compares pectin quality indicators, such as the degree of esterification, molecular weight and gelation, for raw materials dried by the convective method and the combined method consisting of microwave pretreatment and blowing dry air. Curves of comparable pre-drying methods are presented. The rate of pectin yield at the stages of hydrolysis depending on the drying methods is analyzed. Optimal power modes for preliminary microwave drying of citrus raw materials are selected. The data obtained are valuable for both development and improvement of industrial technology of pectin production using environmental methods of extraction without the use of strong mineral acids to increase the yield and quality of pectin.


Molecules ◽  
2021 ◽  
Vol 26 (14) ◽  
pp. 4153
Author(s):  
Doaa Abouelenein ◽  
Ahmed M. Mustafa ◽  
Simone Angeloni ◽  
Germana Borsetta ◽  
Sauro Vittori ◽  
...  

Strawberry is the most consumed berry fruit worldwide due to its unique aroma and flavor. Drying fruits to produce a powder represents one of the possible conservation methods to extend their shelf-life. The aim of the present study was to compare the influence of freezing and different drying methods on the volatile profile of strawberry using the HS-SPME/GC–MS method, in addition to analysis of strawberry jam volatiles. A total of 165 compounds were identified, accounting for 85.03–96.88% of the total volatile compositions. Results and PCA showed that freezing and each drying process affected the volatile profile in a different way, and the most remarkable representative differential volatiles were ethyl hexanoate, hexyl acetate, (E)-2-hexenyl acetate, mesifurane, (E)-nerolidol, γ-decalactone, 1-hexanol, and acetoin. Shade air-dried, frozen, freeze-dried, and oven-dried 45 °C samples retained more of the fruity and sweet aromas of strawberry, representing more than 68% of the total aroma intensity according to the literature. In contrast, the microwave-drying method showed drastic loss of fruity esters. Strawberry jams demonstrated complete destruction of esters and alcohols in most jams, while terpenes were significantly increased. These findings help better understand the aroma of strawberry and provide a guide for the effects of drying, freezing, and jam processing.


Author(s):  
Jan Piecko ◽  
Dorota Konopacka ◽  
Monika Mieszczakowska-Frąc ◽  
Dorota Kruczyńska

Abstract In Poland, Amelanchier berries are of considerable interest to both consumers and potential producers, which presents marketing challenges and opportunities. An attempt was made to preserve Amelanchier berries using a vacuum-microwave method of drying in order to determine its usefulness for producing microbiologically stable dried fruit with a high nutritional values. The berry variety “Prince William” (Amelanchier canadensis) was chosen as the experimental material. Vacuum-microwave drying was performed in two variants: (convective drying [CD] + vacuum microwave method [VMW]) after convective pre-drying of fruit and (VMW) without pre-drying. Unassisted CD was used as the reference method. Application of a vacuum-microwave drying method to Amelanchier berries makes it possible to obtain a stable preserved product of high-quality, yielding moderate shrinkage and good retention of bioactive compounds. An optimized method of vacuum-microwave drying, applied directly to frozen fruit, allows the retention of 70 % of cyanidin glycosides present in the raw material.


2020 ◽  
Vol 6 (2) ◽  
pp. 81-87
Author(s):  
Zhanna Petrova ◽  
◽  
Kateryna Samoilenko ◽  
Vitaly Vishnevsky

Red beetroot is the main raw material which has a high content of betanine with antioxidant properties. An important emphasis in the processing of antioxidant raw materials by drying is to reduce energy consumption for the dehydration process, the maximum preservation of biologically active substances, and to reduce the cost of the final product. Drying is a complex and energy-intensive process. Therefore, to optimize energy consumption during drying and selection of rational modes of dehydration, it is necessary to apply the calculated analysis of heat and mass transfer on the basis of adequate mathematical models. Calculated and experimental results are compared. In general, the comparison of the results of numerical modeling of convection drying processes of the red beetroot sample with the experimental results showed their rather satisfactory qualitative agreement. The calculation model can be used to approximate the characteristics of the drying process of red beetroot, in particular the time required for drying. The obtained results of calorimetric studies allow stating that with correctly selected compositions, not only the components of native raw materials are stabilized, but also the drying process is intensified with the reduction of energy consumption to process.


2019 ◽  
Vol 391 ◽  
pp. 233-238
Author(s):  
E. Gomes da Silva ◽  
E. Santana de Lima ◽  
W.M. Paiva Barbosa de Lima ◽  
A.G. Barbosa de Lima ◽  
J.J. Silva Nascimento ◽  
...  

This paper focuses some fundamental aspects of combined convective and microwave drying of prolate spheroidal solids. A transient mathematical modeling based on the diffusion theory (mass and heat balance equations) written in prolate spheroidal coordinates was derived and the importance of this procedure on the analysis of the drying process of wet porous solid, is also presented. Results pointed to the behavior of the moisture migration and heating of the solid with different aspect ratio. Solids with higher area/volume relationships dry and heat faster.


2020 ◽  
Vol 50 (1) ◽  
pp. 79-86
Author(s):  
Elena Verboloz ◽  
Marina Ivanova ◽  
Vera Demchenko ◽  
Sergey Fartukov ◽  
Nikita Evona

Introduction. Rose hips are rich in macro- and micronutrients. Unfortunately, heat treatment destroys most nutrients. Ultrasonic technologies make it possible to reduce the drying time and lower the temperature regime. The research objective was to adjust ultrasound technology to rose hip production in order to reduce the loss of vitamins and improve the quality indicators of the dried product. Study objects and methods. The research featured rose hips of the Rosa canina species collected in the south of Kazakhstan. This subspecies of wild rose is poor in vitamin C. Nevertheless, this shrub is extremely common in Russia and other countries of the Commonwealth of Independent States. The raw material was dried according to standard methods. One group of samples was treated with ultrasound, while the other served as control. Both groups underwent a sensory evaluation and were tested for moisture and vitamin C. Results and discussion. The rose hips were dried in a combination steam oven with a built-in ultrasonic wave generator. The research revealed the following optimal parameters of the ultrasound drying process: frequency of ultrasonic vibrations – 22 kHz, processing time – 2.5 h, temperature in the combination steam oven – +56°C, initial moisture content – 30%. The resulting product met the requirements of State Standard. The loss of moisture was 57%. According to State Standard 1994-93, the initial moisture content should be 15% or less. Time decreased from 360 min to 160 min, and the initial moisture was 13%. The experiment confirmed the initial hypothesis that ultrasonic treatment improves the drying process by improving quality indicators and preserving vitamin C in raw materials using. Conclusion. Ultrasound treatment during moisture removal from rose hips provides a resource-saving technology that fulfills an economically and socially important function.


2021 ◽  
Vol 1 (1) ◽  
pp. 37-52
Author(s):  
Naum Samoilov ◽  

A critical analysis of the problem of identifying raw materials for hydrotreating diesel fuel by organosulphuric components and quantifying the value of the rate constant of the hydrodesulphurization reaction is presented. It is proposed to describe the raw material as a set of narrow fractions, in each of which the content of various organosulphuric components is considered as a single pseudo-component. The prospects of separate hydrotreatment of diesel fuel pre - fractionated into wide easily and hardly hydrogenated fractions are confirmed, which allows reducing the loading of the catalyst into the reaction unit of the plant by 1.4-1.7 times compared to the traditional process scheme.. It is proposed to use the concept of kinetic coefficient for mathematical modeling of the hydrotreating process instead of the incorrect reaction rate constant in this case. The dependence of the gross conversion rate constant of the raw material on the time of fixing the depth of its hydrodesulfurization is proved by the example of modeling the hydrotreatment of diesel fuel for a number of raw material variants.


Author(s):  
Vadim Karelin ◽  
Vladimir Salomatov

Microwave heating is widely used in the energy, construction, forestry, chemical and food industries, etc. There are many publications that discuss the main mechanisms that occur during microwave heating. For a better understanding of these processes and the development of high-performance microwave installations, mathematical modeling is necessary. As a rule, nonlinear models that most adequately describe these phenomena use a numerical algorithm for calculations. The authors of this report are engaged in approximate analytical approaches for microwave heating and microwave drying of bodies, which, with a controlled decrease in accuracy, nevertheless allow you to display the main processes and evaluate such heating and drying parameters as: temperature and moisture distribution, heating time, drying speed, reaching maximum values, etc. In this work, we consider a model of microwave heating in the form of a ball with uniform irradiation of microwave energy in the conditions of radiation-convective interaction of the product with the environment. The absorption of the microwave inside the material is given by the law of the Bouguer. In this case, a number of simplifications were made: the electrophysical and thermophysical properties of the material are constant, the material is homogeneous in composition and properties.


Author(s):  
Aurelija Kemzūraitė ◽  
Algirdas Raila ◽  
Kristina Bimbiraitė ◽  
Olga Kornyšova ◽  
Audrius Maruška

Medicinal herbs after their harvesting participate in heat exchange with the environmental, as does each organic and hygroscopic material. Drying helps to conserve the medicinal raw material with the maximal preservation of its quality. The present investigation deals with the influence of the surrounding air factors (temperature and relative humidity) on drying intensity. The study object was aboveground part of hyssop (Hyssopus officinalis L.), i.e. Hyssopi herba was used as medicinal raw material. The aim of the study was to offer a mathematical model of time‐related medicinal herbs moisture dynamics and to show its qualitative agreement with the physical model of diffusion as well as to determine the optimum ventilation intensity of medicinal herbs. Drying of Hyssopi herba using active ventilation was investigated. Ventilation intensity and the parameters of the drying agent influenced the processes of moisture dynamics, the total drying time and the quality of Hyssopi herba. The basic prerequisites of the drying process have been analysed. A mathematical model of moisture dynamics has been proposed and used to show the dependence of theoretical moisture dynamics on ventilation velocity. The obtained experimental values of moisture content dynamics during the drying of Hyssopi herba have been shown to agree with theoretical dependences. Santrauka Vaistiniai augalai, kaip ir kiekviena organinė higroskopinė medžiaga, dalyvauja šilumos mainų procese su aplinka. Džiovinant siekiama konservuoti vaistinius augalus iki reikiamo drėgnio, kiek įmanoma išsaugant jų kokybę. Nagrinėta aplinkos oro veiksnių (temperatūros ir santykinio oro drėgnio) įtaka džiovinimo intensyvumui. Tyrimams naudota antžeminė vaistinio isopo (Hyssopus officinalis L.) dalis, t. y. vaistinė augalinė žaliava – isopų žolė (Hyssopi herba). Tyrimų tikslas – sudaryti drėgmės kitimo per tam tikrą laiką matematinį modelį, taikant gautą difuzijos sprendinį, bei nustatyti optimalų ventiliavimo intensyvumą. Tirtas Hyssopi herba džiovinimo taikant aktyviąją ventiliaciją procesas. Išanalizavus pagrindines džiovinimo sąlygas, sudarytas drėgmės kitimo priklausomybės nuo ventiliavimo intensyvumo, matematinis modelis. Ventiliavimo intensyvumas ir džiovinimo agento parametrai turėjo įtakos drėgmės mainų procesams, džiovinimo trukmei ir vaistinės augalinės žaliavos kokybei. Gauti drėgnio kitimo džiovinant Hyssopi herba rezultatai patvirtino, kad teorinės priklausomybės kokybiškai atitinka tiriamąjį procesą. Резюме Лекарственные растения, как и всякий органический гигроскопический материал, участвуют в процессе теплообмена с окружающей средой. С помощью сушки требуется консервировать лекарственные растения до нужной влажности, максимально сохраняя их качествo. Исследовалось влияние температуры и относительной влажности окружающего воздуха на интенсивность сушки. Объект исследования – наземная часть лекарственного иссопа (Hyssopus officinalis L.), т.е. лекарственное сырьё Hyssopi herba. Целью исследования было создать математическую модель изменения влажности с течением времени, применяя полученное решение диффузии, и определить оптимальную интенсивность вентиляции. Процесс сушки Hyssopi herba исследовался способом активной вентиляции. Различные параметры интенсивности вентиляции и сушильной среды влияли на процесс влагообмена, продолжительность сушки и качество лекарственного сырья. Произведен качественный анализ основных предпосылок процесса сушки. Предложена математическая модель изменения влажности, и на ее основе получена теоретическая зависимость изменения влажности от интенсивности вентиляции. Полученные результаты подтвердили соответствие между теоретической моделью и экспериментальными данными.


Author(s):  
Alexander Sklyar

The subject of this research is the processes of price formation for raw materials depending on the demand for end consumer products. The article reviews a mathematical model that is based on the principle of maximum utility. The proposed model is founded on the stage-by-stage determination of the production output and consumption of end products, as well as corresponding prices depending on the prices of used raw materials and semi-finished products. The prices for intermediate products and raw materials are formed depending on the need for end products output with their optimization by demand. The article provides the basic mathematical ration with regards to using principle of maximum utility applicable to the demand-supply model and its implementation in multi-stage production. The acquired results indicate weak dependence of production output and prices for end products on the cost of raw material in terms of advanced refining. With limited production capacity of raw materials, the dynamics of prices is well predicted. The results of modeling, compared to the available statistical data, indicate the adequacy of the proposed model to the unfolding economic processes. It is determined that the accuracy of price prediction for raw products with a significant volume of its subsequent processing is limited.


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