scholarly journals Investigation of low-temperature drying modes plant capillary-porous materials spherical shape

Author(s):  
V.М. Pazyuk

The results of experimental studies of the drying of capillary-porous materials of spherical shape from the influence of the temperature of the heat carrier are given.Spherical granules with a diameter of 2,2 mm were taken to determine the rational modes of drying of capillary-porous materials. For a better evaluation of the nature of the drying process, experimental design studies were carried out on a convective drying stand in an elementary layer.The program of automatic collection and processing of information allows obtaining data on changes in the mass and temperature of the sample during the removal of moisture, and also performs calculations of kinetics of drying in absolute and relative coordinates. This makes it possible to obtain and compare the kinetic and velocity characteristics of colloid capillary-porous materials drying faster, more accurately and reliably.By the method of Krasnikov V.V. the kinetics of drying of capillary-porous materials of spherical shape with a diameter of 2,2 mm with construction of a generalized drying curve with determination and calculation of drying coefficients is considered.The generalized curve of drying rate is constructed and obtained, which allows us to generalize the process of drying of a capillary-porous spherical material. Also, get the formula and determine the overall length of the drying process through the drying rate for each heat treatment.When comparing the values of the process length obtained by experimental studies and determined by the calculations, the experimental error from the calculation does not exceed 3%.The analysis of heat-mass-exchange processes of drying by means of calculations of temperature coefficient b, Rebinder Rb criterion, heat flow q and coefficient of heat transfer α from the influence of heat carrier temperature has been carried out.

Author(s):  
Yu.F. Snezhkin ◽  
V.М. Paziuk ◽  
Zh.O. Petrova

The mathematical processing of experimental data obtained during the drying of spherical form of capillary-porous materials on a convective drying bench allows us to determine the influence of various factors on the process. The main factors influencing the kinetics of drying of capillary-porous materials of spherical shape are the temperature and velocity of the heat carrier, as well as the initial moisture content of the material. For each factor, the variation levels corresponding to the optimal conditions for conducting experimental studies with low-temperature drying conditions are recommended. For a mathematical description of the duration of drying of capillary-porous materials, we use an orthogonal composite plan of the second order. As a result, the proposed mathematical model of the process obtained regression equations and the response surface of the duration of drying of capillary-porous materials of spherical shape. The obtained regression equations of the drying time give a detailed description of the influence of both individual and joint actions of factors, the significance of these parameters is determined by the corresponding coefficients according to Student's criterion. Also, the adequacy of the mathematical model according to Fisher's criterion, which corresponds to the real object, is checked. The construction of the response surfaces of the drying time of capillary-porous materials indicates the nature of the effect of these factors in the given range of variation.


Author(s):  
Yu.F. Snezhkin ◽  
V.М. Paziuk ◽  
Zh.O. Petrova

Heat pump technologies have become widely used in space heating and air conditioning systems, and the heat pump can be used for low-temperature drying of capillary-porous materials. Recuperative and condensing heat pumps, which allow both drying and cooling of the material, have become the most widespread. The developed condensing heat pump drying unit with a mine chamber implements a low-temperature drying process of spherical capillary-porous materials at a drying agent temperature of 40-50°C with a decrease in material humidity by 11% to a final humidity of 8%. Experimental studies on a heat pump drying unit for drying capillary-porous materials of spherical shape indicated a significant reduction in average energy costs per process up to 3700 - 4100 kJ/kg of evaporated moisture. The increase in energy consumption increases significantly in the second part of the second period, where heat consumption can reach 5000 - 5350 kJ/kg of evaporated moisture. The use of condensing heat pumps for low-temperature drying of capillary-porous materials has shown high energy efficiency compared to existing drying technologies.


Author(s):  
Vadym Paziuk ◽  
Eugenia Shemanska ◽  
Dasha Paziuk

Studies on finding rational regimes for drying rapeseed based on drying kinetics and qualitative characteristics are presented. The value of the acid number of oil and laboratory germination of rapeseed on the 7th day of germination were taken as a qualitative characteristic. Experimental studies of the kinetics of the rapeseed drying process were performed on a convective drying stand using an automatic program for collecting and processing information, which makes it possible to obtain more accurate experimental data. According to the obtained experimental data with the help of an automatic program for collecting and processing information, graphs of the process kinetics from the influence of the coolant temperature are constructed. The presented graphs show the drying curves and drying speed curves that characterize the drying process that takes place during the period of falling drying speed. The study of the kinetics of the drying process of rapeseed in a single-stage mode at coolant temperatures of 50 - 80°C showed that for better quality it is necessary to use low-temperature modes. The acid number of oil in this temperature range does not change significantly and is 1.03 - 1.8 mg / g of oil. These values of the acid number of the oil correspond to the normative value. The greatest effect on the germination of rapeseed is observed from the temperature of the coolant. Increasing the temperature by 10 ° C in the temperature range from 50 to 80 ° C reduces the germination of the material. According to laboratory studies, we determined the drying regime of 50 ° С with a germination of 97% to be the most expedient and rational. All other drying regimes significantly reduce the germination of rapeseed and can not be recommended, as the germination value is less than the state standard of Ukraine 2240-93.


Author(s):  
T. N. Tertychnaya ◽  
A. A. Shevtsov ◽  
S. S. Kulikov

Experimental studies of the kinetics of the process of drying triticale grain during counter-current-direct blowing of the grain layer were carried out. In the experimental installation, a programmed change in the direction of the drying agent flow through the grain layer was carried out and the actual conditions of the drying agent supply through the supply and discharge boxes of the shaft grain dryer were emitted. Analysis of drying curves and drying rate of triticale grain showed the presence of only a period of decreasing drying rate, in which the intensity of moisture diffusion is significantly less than the intensity of moisture exchange. The organization of the experiment made it possible to fully adapt it to industrial mine grain dryers, in which the drying process is carried out in a continuous mode. Based on the results of the study, an empirical model of the drying process is proposed in the form of an exponential function, which establishes a unique functional relationship between the current moisture of the grain and the main parameters of the process: temperature, speed, moisture content of the drying agent and the thickness of the blown layer. Taking into ac-count the requirements to the process modes of grain drying, the triticale analyzes the ratio between the grain temperature and its humidity at various values of the mode parameters, which is proposed to be used as a restriction on the drying temperature mode.


Author(s):  
А.С. ДАНИЛЬЧЕНКО ◽  
Т.Г. КОРОТКОВА ◽  
С.Ю. КСАНДОПУЛО

Рассмотрена кинетика сушки послеспиртовой барды при 60°С. Объектом исследований была модельная смесь, состоящая из воды, белков, жиров и растворимых углеводов. Представлены результаты исследований кинетики испарения воды и смесей вода–масло, вода–белок, вода–сахар, вода–масло–белок–сахар, помещенных в чашку Петри. Процесс испарения в изотермических условиях протекал в сушильном шкафу Memmert. Установлено, что добавление вещества в воду снижает скорость испарения воды в периоде постоянной скорости сушки, в периоде падающей скорости сушки продолжительность испарения возрастает. По результатам кинетики сушки модельных смесей можно определять коэффициенты активности компонентов и проводить исследование процесса сушки реальных смесей при проектировании сушилок. The kinetics of drying of the distillery dregs at 60°C is considered. The model mixture containing water, proteins, oils and soluble carbohydrates was the object of research. The results of experimental studies of the kinetics of evaporation of water and mixtures of water-oil, water-protein, water-sugar, water-oil-protein-sugar, placed in a Petri dish, are presented. Evaporation under isothermal conditions was carried out in a Memmert drying cabinet. It is established that the addition of the substance into the water reduces the evaporation rate of water in the period of constant drying speed, the duration of evaporation in the period of falling drying speed increases. According to the results of the kinetics of drying model mixtures, it is possible to determine the activity coefficients of the components and conduct a study of the drying process of real mixtures in the design of dryers.


2020 ◽  
Vol 02 (10) ◽  
pp. 45-54
Author(s):  
Rustamov E.S. ◽  
◽  
Djuraev Kh.F. ◽  
Gafurov K.Kh. ◽  
◽  
...  

The article covers results of research of drying process of apricot fruits by the method of three-stage energy supply. The main stages of drying have been defined, including: pulsed infrared heating, instantaneous pressure impact, convective drying. Optimal technological parameters of energy supply in the process of drying apricot fruits at each stage have been developed. The choice of the method for the experimental determination of the drying speed by the parameters of the drying agent for the capillary-porous material is substantiated. The sequence of changes in moisture content in a given material under the influence of a three-stage energy supply is described. The conditions for drying fruits are established and the values of the drying speed in the first period for various methods of energy supply have been selected.


Author(s):  
Kateryna Slobodianiuk ◽  
◽  
Kateryna Samoilenko ◽  

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.


Author(s):  
Gabriela Silveira da Rosa ◽  
Sai Vanga ◽  
Yvan Gariepy ◽  
Vijaya Raghavan

The aim of this study was to investigate the effect of convective and vacuum drying on properties of biodegradable films. The film-forming solutions were prepared with bovine gelatin and carrageenan. The films solutions were dried in convective and vacuum dryers at temperatures of 40, 50 and 60 oC. The results of convective drying kinetics of biofilms showed a constant drying rate period followed by a falling drying rate period. The results of thickness showed dependence with moisture content present in films.Carrageenan films showed promising results, with high values of tensile strength and elongation for convective drying at 60 oC. Keywords: gelatin; carrageenan; drying; biofilm 


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