Substantiation of the Energy Efficient Schedules of Drying Grain Seeds

It is important to study the patterns of drying grain seeds in order to improve the energy efficiency of the process. Energy efficiency is one of the main parameters that define the choice of a drying schedule. Traditional drying technologies are based on low temperature schedules, which do not allow significantly intensifying the process by increasing the temperature of the heat agent because of substantial reductions in the quality of the material. To adequately assess the drying schedules, we conducted the study of drying grain seeds at low temperatures aimed to preserve the seed properties of the material. To increase the energy efficiency of the drying process, a step-by-step descending low-temperature drying schedule was suggested, which provides for the required quality of seed material. All the proposed technical solutions for the energy-efficient schedules of drying grain seeds were summarized in the recommendations for industrial drying in column type direct-flow grain dryers.

Energy analysis of the production line for canned carrot production

An energy-saving scheme for the production of candied carrots has been developed. The developed scheme includes: washing of raw materials with 1 % NaHCO3 solution, reduction of water consumption for blanching, reduction of syrup consumption for saturation of raw materials with sugar. A new drying technology is introduced: candied fruits are dried in a variable temperature mode, namely: in the initial stages with a heat agent at a temperature of 70 °C, at the final stage – with a heat agent at a temperature of 20 °C. The process of modeling the traditional and energy-saving scheme of candied carrot production in the universal simulation software ChemCad is carried out. The simulation results are analyzed. It is proved that the total energy efficiency of the implemented technology is 340.4 MJ / h or 354.6 kJ / kg of finished product.

MECHANISM OF FILTRATION DRYING OF ORGANIC MATERIALS OF FIBROUS STRUCTURE AND RESULTS OF RESEARCH OF EXTERNAL HEAT EXCHANGE

One of the high-intensity methods for removing both free and bound moisture is filtration drying. This is due to the fact that during filtration drying, the heat agent is filtered through the porous structure of the wet material, which is placed on the perforated partition in the direction "wet material–perforated partition". The velocity of the heat agent in the pores and channels of a stationary layer of wet material determines the thickness of the boundary layer (hydrodynamic, thermal, and diffusion) and, accordingly, the values of the heat and mass transfer coefficients. In addition, the surface of heat and mass transfer is the total surface of the pores and channels through which the heat agent is filtered. The filtration rate of the heat agent is determined based on technical and economic considerations, given that its increase affects the growth of pressure loss. Moreover, the actual speed of the heat agent relative to the layer elements is much higher than in the case of drying by any other methods (in a fluidized bed, during drying in pneumatic transport dryers, etc.). Large heat and mass transfer surfaces and the speed of the heat agent in the pores and channels of the stationary layer of wet material provide high heat and mass transfer coefficients and, accordingly, the intensity of filtration drying. This article presents the results of the study of external heat exchange between the heat agent and dry particles of organic materials of fibrous structure, in particular raw cotton and its stems, and the mechanism of filtration drying.

FORMALIZATION OF THE COTTON DRYING PROCESS BASED ON HEAT AND MASS TRANSFER EQUATIONS

The paper deals with the construction of a mathematical model of the cotton drying process, taking into account the thermal and mass transfer properties of raw cotton components. To determine changes in the temperature of the fibre and raw cotton seeds, the application of Fourier's law is proposed. The mathematical dependence of the change on the humidity of the cotton fibre and seeds along the length of the drum is determined. The rational value of the heat agent consumption in the process of drying raw cotton is also determined. Research methods are based on the provisions of modern trends in management theory and identification. Mathematical models are constructed using analytical methods and equations that describe the physical properties of an object. Methods for constructing a mathematical model usually rely on experimental methods, in particular, the method of acceleration curves, and as a result, the mathematical description becomes a priori inaccurate. It is shown that the mathematical model used is quite adequate for the dynamics of a real object, fully describes it, and characterizes it over the entire range of changes. The analysis of the developed mathematical model based on simulation showed the adequacy of the obtained mathematical dependence of the temperature regime of the cotton drying process with the consumption of heat agent. ABSTRAK: Kajian ini membincangkan tentang penciptaan model matematik bagi proses pengeringan kapas, dengan mengambil kira terma dan sifat-sifat pindah jisim komponen kapas mentah. Bagi mendapatkan perubahan suhu fabrik dan biji benih kapas mentah, penggunaan hukum Fourier telah dicadangkan. Kebergantungan matematik pada perubahan kelembapan fabrik kapas dan biji benih sepanjang drum telah diperolehi. Nilai bersesuaian menggunakan ejen haba dalam proses pengeringan kapas kering mentah didapati. Kaedah kajian berdasarkan tren moden dalam teori pengurusan dan pengenalpastian. Model matematik dibina dengan menggunakan kaedah analisis dan persamaan yang menerangkan ciri-ciri fizikal pada objek. Kaedah bagi membina model matematik selalunya bergantung pada kaedah eksperimen, khususnya, kaedah pecutan melengkung, dan hasilnya, penyataan penaakulan matematik menjadi tidak tepat. Model matematik yang digunakan adalah cukup bagi objek dinamik sebenar, dengan penerangan penuh dan perincian ke atas keseluruhan perubahan. Analisis model matematik yang terhasil berdasarkan simulasi, dilihat cukup kebergantungan matematik terhasil melalui proses pengeringan kapas pada aturan suhu dengan ejen haba.

Investigation of the Energy-Saving Method during Candied Fruits Filtration Drying

The drying process, which is the limiting and power-consuming stage of candied fruits production, has been considered. The heat-transfer processes during the filtration drying of pumpkin candied fruit have been investigated. The filtration drying of finished candied fruits (80 °C) is the filtration of a hot heat agent (100 °C) in the direction of "candied layers – grate". As a result of experimental studies, the kinetic curves of candied fruits drying, as well as the dependence of temperature on the height of the candied fruit layer, were obtained. The experimental data confirm the zonal mechanism of the filtration drying.It was found that during the filtration drying, the upper layers, which reached their final moisture content, overheat and accumulate a considerable amount of unused energy. It was proved that the accumulated energy can be used for drying the lower layers with simultaneous cooling the upper ones. On the basis of the equation of non-stationary heat-mass transfer, the amount of heat is calculated, which will be sufficient to dry the bottom layer. The stoppage time of hot heat agent supply and start of cold heat agent supply were determined. Filtration of cold heat agent through a layer of candied fruits makes it possible to cool the layer, reduce drying time and energy costs for the process.Dried candied fruits have sufficient shelf life, good taste and organoleptic properties.