Designs Of Dryers Research Articles

IMPROVEMENT OF THE EXISTING INTERNAL HEAT EXCHANGE PROCESS IN MODERN BELT DRYERS

Different designs of dryers have been created on the basis of the general rules of providing external energy during heat treatment of dispersed materials, which have their own advantages and disadvantages. One of the promising methods of accelerating the drying process of dispersed materials is the use of belt dryers. One of the main advantages of devices that work in this way, called belt dryers, is the simplicity of the mechanical devices that move inside them, which increases the accuracy of the dryer. The small dimensions allow us to save a lot of rare stainless steel used for their production. Due to the heat applied to the belt dryers, the dispersed material undergoes intensive thermal processing, and its processing is fast. In this way, the contact time of the dispersed material and the heating surface is formed, and the efficiency of the contact drying process increases many times.

Optimal Designs of Air Source Heat Pump Dryers in Agro-food Processing Industry

Optimal Designs of Air Source Heat Pump Dryers in Agro-food Processing Industry

COMPARATIVE EVALUATION OF THE STRUCTURAL DESIGN OF MICROWAVE CONVECTIVE HOP DRYERS

In hop production, the main scientific problem is the low energy efficiency of hop dryers with convective heat supply and the absence of small-sized mobile continuous-flow hop dryers for farms that ensure the preservation of the consumer properties of hops at reduced operating costs. In order to reduce the operating costs of drying hops, work is being carried out aimed at clarifying the drying modes that contribute to the best preservation of consumer characteristics, and the improvement of technologies and technical means that would reduce operating costs. A new method of drying hops by ultra-high-frequency energy supply deserves attention. (Research purpose) The research purpose is revealing the effectiveness of an ultrahigh-frequency convective hop dryer of continuous-flow action by evaluating the developed structural designs of hop dryers with metal-dielectric resonators that ensure uniform drying and disinfection of freshly harvested hops and electromagnetic safety without a shielding housing at reduced operating costs in the conditions of hop farms. (Materials and methods) Carried out three-dimensional modeling of the structural designs of hop dryers in the Compass 20 program, determined the electrodynamic parameters of the ”generator-resonator“ system in CST Microwave Studio. (Results and discussion) Solved the problem of optimizing the structural design and dimensions of metal-electric resonators. It was shown that the main criteria are the correctly agreed parameters of the electrodynamic system ”generator-resonator“: the intrinsic Q-factor of the resonator, the voltage of the electric field, its uniformity of distribution, the power of the radiation flux, the volume of the resonator. The electro-dynamic parameters of 11 hop dryers with different designs of resonators were analyzed: hemispherical, semi-cylindrical, cylindrical, toroidal, prismatic, ellipsoid and others. (Conclusions) It was found that toroidal and hemispherical resonators have a maximum intrinsic Q-factor of up to 8000. It was determined during the evaluation of deviations from the average value of the intervals of variation of the criteria that hop dryers with resonators in the form of a paraboloid and hyperboloid, and semi-cylindrical, are effective.

EVALUATION OF THE EFFICIENCY OF A MULTI-CHANNEL DUST COLLECTOR USING NUMERICAL SIMULATION

Multi-channel dust collectors are based on previously known designs of vortex dryers for bulk products. However, their use for air dust removal is promising. In earlier studies of these devices using numerical simulations, the dust capture coefficient was not evaluated, although it is the most important indicator of their efficiency. In this article, the numerical simulation of MCDC is carried out. The first stage of modeling is the calculation of the gas flow velocity and pressure fields in the device under study. At the second stage, a large number of trajectories of dust particles of different diameters were calculated with subsequent statistical processing. Dust capture coefficients and hydraulic loss coefficients were calculated. It is shown that for the reliability of the results of the numerical experiment, the number of dust particles should be at least 2000. To determine the effect of the outer half-shells on the efficiency of the device, these half-shells were discarded, as a result of which the multi-channel dust collector turned into a cyclone. The comparison of characteristics showed that, other things being equal, the devices being investigated have some advantages over cyclones in capturing of small fractions of dust. The hypothesis that the capture of particles in curved channels occurs mainly due to particle collisions with the front edges of metal half-shells was put forward and refuted. The results of numerical modeling do not support the hypothesis that some dust particles rotate along closed trajectories and form a filter for other particles. The formulas of other authors, which do not take into account the parameters of dust particles, are recognized as unworkable. The speculations of some authors about the influence of the Ranque-Hilsch vortex effect on the process of dust capture cannot be taken into account due to the low subsonic air velocities under the operating conditions of the apparatus.

Solar Hybrid Drying System for Marine Applications – A Comprehensive Review

ABSTRACT At present, the fisheries sector’s contribution to the world as a source of nutrients and wealth is highly significant. Fisherfolks harvest marine products like fish, prawns, and squid in a surplus amount; however, due to the non-availability of cold chain facilities, a lot of items are spoiled. Hence, drying is practiced in most parts of the world to preserve marine products. Studies have reported use of various designs of the solar hybrid dryer for drying of marine products. However, there is no comprehensive report on different designs of solar dryers and their application, especially in the drying of marine products. Hence, this review focused on solar drying, various designs of solar-based dryers, and the application of solar hybrid drying systems for marine products including the quality analysis of the final product.

Assessment of eco‐thermal sustainability potential of a cluster of low‐cost solar dryer designs based on exergetic sustainability indicators and earned carbon credit

This research aims to establish the interconnectivity between solar dryer designs and the exegetic-sustainability performance of solar dryers. This is to assist energy policymakers and fabricators to establish design standards and make the right choice for waste exergy management strategy for environmental sustainability. Therefore, in this study, the exergy-based sustainability indicators and earned carbon credit were used to assess and compare the performance of four different designs of solar dryers of equal collector capacity under the same external environmental conditions in the same town. In terms of better sustainability indicators that include high exergy efficiency, lower waste exergy emission, higher sustainability index and lower lack of productivity, solar dryer designs with single-pass triple air movement direction with inlet air powered by wind generator had the best indices for environmental sustainability. In contrast, the natural convection mix-mode solar dryer design had the lowest environmental effect factor and destruction coefficient while the indirect natural convection solar dryer had the highest energy recovery ratio based on exergy output from water evaporation. However, the mix-mode solar dryer powered by the wind generator earned the highest carbon credit. The exergy efficiency ranged from 19.09 to 52 % for the four cases, whereas the waste exergy ratio ranged from 0.52 to 0.81. The LOP value ranged from 2.95 to 19.96. Similarly, the sustainability index ranged from 1.28 to 2.5, the average environmental destruction coefficient varied from 3.96 to 20.96, the exergy recovery ratio for the four dryers varied from 0.001825 to 0.12405, and the earned carbon credit ranged from $442. 3 to $2630.5.

Application of the method of structural-parametric identification to determine the mathematical model of a multidimensional object with distributed parameters and delay

Drying is one of the most responsible and energy-intensive post-harvest grain processing operations. The constant rise in heat prices has led to the search for new designs of grain dryers, or improvements to existing ones. Studies of well-known scientists such as Romankov, Rezchikov, Rashkovskaya have proven the potential effectiveness of using a fluidized bed for drying grain. The degree to which this drying efficiency approaches the potential is determined by how much the change in the actual humidity of the material during drying approaches the theoretical drying curve at the same resource consumption and the same initial state of the material to be dried. Taking into account the provisions of the theory of optimal control indicates that max-imizing the accuracy of stabilization of a given value of the height of the fluidized bed should be achieved by developing an optimal multidimensional stabilization system of the specified height. The basis for solving the first of these is the study of the design of a fluidized bed grain dryer. The decomposition of the grain dryer allows to present it in the form of a set of multidi-mensional objects with pure delay. The size of this set is determined by the number of cascades, and the dynamic characteristics of its elements depend on the distance of the cascade to the gate Δ. Automation of control and management of processes of processing and storage of grain opens wide opportunities for increase of efficiency of use, increase of productivity of current lines, further reduction of labor costs and improvement of quality of processing of grain. If today most of the known dryers have their own mathematical model, this fluidized bed dryer is new, incompletely studied and therefore needs its own mathematical description in order to develop a system of automatic control of its parameters. Therefore, this paper shows the practical application of the technique of identification of signals "input-output" of the dryer for the dispersed material of the cascade type. According to the spectral and mutual spectral densities of the signals, using the technology of structural-parametric identification, a matrix of transfer functions of the dryer was found, which is a multidimensional dynamic object with distributed parameters with delay, which is affected by various perturbing factors.

SIMULATION OF THE GRAIN DRYING PROCESS IN BUNKER DRYERS USING HELIOCOLLECTORS

Drying is the main method of preparing agricultural materials for storage. Today, there are a variety of drying plants in the world that use solar radiation energy to heat a drying agent or drying material. But most designs of solar dryers are adapted to work in stationary conditions, special rooms. Reducing energy consumption for drying grain materials is an urgent problem, which is solved in two main ways - technical modernization of existing drying equipment and development of new energy-saving methods and modes of drying agricultural materials and their implementation on existing and upgraded facilities. Both the first and second way of solving the problem of energy saving is based on a mathematical description of the processes of heat and mass transfer.The mathematical model of thermal modes of the drying unit is a set of interconnected models of its individual elements with external kinematic parameters (atmospheric air temperature, intensity of solar radiation, etc.). The model of a single element of the system is a system of differential equations in differential form, limit and initial conditions, which reflect the basic physical dependences of the studied processes.The aim of the research was to formulate a mathematical model based on the theory of heat and mass transfer to determine the dynamics of the development of interconnected nonstationary fields of temperature and moisture content of the material and the drying agent - air.Numerical implementation of the proposed mathematical models in a standard mathematical package allows to analyze the performance of equipment, in particular film solar collectors, for convective drying of dispersed agricultural materials in the layer depending on the parameters of the feed material, solar radiation intensity or (and) heat generator capacity atmospheric air.

Effects of roof angle, inlet gap size and dryer height on temperature and relative humidity in a chimney-dependent solar crop dryer

A chimney dependent solar crop dryer (CDSCD) was developed and studied. Design of Experiment (DOE) was employed using statistical three level non randomized factorial experimental design in Minitab statistical software version 19.0. The study of effects of roof angle, inlet gap size and dryer height on dryer temperature revealed that the height at which the drying tray is positioned (A) and the inlet gap (C) influences the highest temperature difference, 30.4 °C. It was concluded that dryer temperature is high when the inlet gap is small (range of inlet area to exit area ratio of 1.8128:1 to 1.0877:1) and the maximum ratio of height of dryer to drying tray’s position is 2.18. Optimal values for achieving high temperature difference response greater than or equal to 32.6 °C are minimum roof height of 84 cm, inlet to outlet area ratio of 1.0877:1 and minimum roof angle of 81°. The effect of the three parameters on relative humidity revealed that the combined effect of roof angle and inlet gap (AB) attained the highest standardized effect of 6.6. The optimal values for achieving low dryer relative humidity (when loaded with 1 kg of cassava) were roof angle of 64°, inlet to outlet area ratio of 2.5379:1 and minimum time of 19 hours. This could serve as effective tool for comparing different designs of CDSCD dryers for optimum humidity and drying performances and be used to subsequently refine solar crop dryer design.

Efficient solar drying techniques: a review.

In the absence of effective drying techniques, a lot of food gets wasted as there is a lack of post-harvest processes. In India, most of the agricultural produces like paddy, maize, wheat, corn, oil seeds, pulses, chillies, etc. require a temperature range of 50-80 °C for effective drying. Hence, in these conditions, solar drying techniques seem to be the most economical; also, it is safe and eco-friendly. Various types of solar dryers are used across India and worldwide; these are direct solar dryer, green house dryer and indirect solar dryer. Nowadays, indirect type solar dryers are most commonly used because of their several advantages over direct solar dryers. In case of indirect type solar dryers, the products to be dried are kept inside a separate compartment known as drying chamber. Hot air is obtained from the solar collectors either by direct heating method or by using a secondary heating medium and then supplied to the drying chamber for heating of the products. This paper presents a detailed review of various innovative designs of indirect type solar dryers and compares the performance of different types of dryer configuration in terms of collector efficiency, dryer efficiency, drying time and maximum air temperature. Also, the effects of various operating parameters on the thermal performance of such dryers have been discussed.

Performance evaluation of the DehytrayTM solar drying device using plantain, pepper and okra under the tropical conditions of Oyo State, Nigeria

The quest for improved performance of access to solar dryers has led to the development of several designs of solar dryers. This study evaluated the performance of the DehytrayTM, a relatively new solar dryer made up of food grade plastic, in comparison with sun drying using plantain, okra and pepper as test crops in five replicated trials. Freshly harvested crops were divided into two batches, weighing 1.3 kg each. The first batch was blanched with salty water (7 g/100 g) for 2 to 4 min while the other was unblanched. Fresh, sun-dried and solar dried samples were analyzed for their proximate composition and microbial load using standard methods. Drying efficiency was determined using standard equations while three thin layer drying models were applied to the experimental data compared according to their coefficient of determination (R2) and root mean square error (RMSE), predicted by non-linear regression analysis using Microsoft Excel solver, 2018. Mean temperatures ranged from 55-65°C and 25.5-34.3°C for DehytrayTM solar dryer and sun drying, respectively. Efficiency of the dryer ranged between 16.6-28.1% (blanched) and 16.3-33.7% (unblanched) for plantain, 18.2-29.8% (blanched) and 19.4-28.8% (unblanched) for okra and 11.7-17.8% (unblanched) and 11.2-17.7% (blanched) for pepper. Efficiency of the sun drying ranged from 1.1-2.1% (blanched) and 1.4-2.3% (unblanched) for plantain, 1.3 -3.1% (blanched) and 1.6- 3.7% (unblanched) for okra and 0.7 -0.9% (unblanched) and 0.7 -1.1% (blanched) for pepper. There was a good retention of nutrients on the solar dried crop compared to that of the sun-dried crop. Mean airflow rate in the DehytrayTM was 0.021 m3/s compared to 0.49 m3/s in the sun drying. The portability and performance of the DehytrayTM makes it a viable option in the humid tropics. Key words: DehytrayTM, drying model, sun drying, solar drying, efficiency, postharvest operation.

Energy analysis and economic feasibility of wood dryers integrated with heat recovery unit and solar air heaters in cold and hot climates

In this paper, the energy performance and economic feasibility of conventional wood dryer systems integrated with a heat recovery unit and solar air heaters are numerically investigated. Four different designs of wood dryers, composed of an insulated drying chamber, a heat recovery unit (HRU), a flat plate air collector (FPC), a photovoltaic/thermal air collector (PVT) and an auxiliary heater, are presented and compared. Annual dynamic simulations were carried out using a heat and mass transfer model with realistic meteorological data from two different climatic zones as boundary conditions. The effect of recovering waste heat and integrating each type of solar air heaters on the wood dryer energy consumption are presented and analyzed. Results show that recovering waste heat from conventional wood dryers in cold climate is more beneficial than in hot climate with an annual energy consumption reduction up to 41%. It is also shown that using a combined heat recovery unit and PVT collector improved significantly the energy efficiency of conventional dryers and reduced by about 67.5% and 49.5% the yearly energy consumption in hot and cold climates, respectively. Based on the economic analysis, the use of the HRU is beneficial in both climatic zones with a maximum payback period of 2 years. However, the use of the PVT collector is recommended only for wood dryers in hot climates where the payback period is about 3.5 years.

Identification of signals as one of the stages of synthesis of the system of automatic stabilization of the height of the fluidized bed in the grain dryer

Drying is one of the most responsible and energy-intensive post-harvest grain pro-cessing operations. The constant rise in heat prices has led to the search for new designs of grain dryers, or improvements to existing ones. Studies of well-known scientists such as Romankov, Rezchikov, Rashkovskaya have proven the potential effectiveness of using a fluid-ized bed for drying grain.The degree to which this drying efficiency approaches the potential is determined by how much the change in the actual humidity of the material during drying approaches the theoretical drying curve at the same resource consumption and the same initial state of the material to be dried.The study of the designs of fluidized bed grain dryers showed that they show irregular fluctuations in the height of the fluidized bed, and, accordingly, the efficiency of energy use for drying. The reason for this phenomenon is related, on the one hand, to random fluctua-tions in the amount of grain in the fluidized bed, and on the other - to the shortcomings of the system of automatic stabilization of its height.Taking into account the provisions of the theory of optimal control indicates that max-imizing the accuracy of stabilization of a given value of the height of the fluidized bed should be achieved by developing an optimal multidimensional stabilization system of the specified height. The basis for solving the first of these is the study of the design of a fluidized bed grain dryer.The decomposition of the grain dryer allows to present it in the form of a set of multidimensional objects with pure delay. The size of this set is determined by the number of cascades, and the dynamic characteristics of its elements depend on the distance of the cascade to the gate.The degree of connections between input-output signals in the form of correlation and cross-correlation functions was studied, and the physical processes occurring in the grain dryer were analyzed. As a result of applying the Blackman-Tukey algorithm to the implemen-tations of the components of the control signal vectors and output signals, estimates of the corresponding correlation functions and spectral densities for all elements of the set of con-trol objects were obtained. The discrete Fourier transform of smoothed estimates of correla-tion and cross-correlation functions allowed us to calculate estimates of the spectral and mutual spectral densities of the respective signals. Approximation of spectral and mutual spectral density estimates by the method of generalized logarithmic frequency characteristics allowed to determine the mathematical description of these signals in the form of spectral density expressions, which will be the basis for the next stage of object identification.

MODELING OF DEGRADATION PROCESSES OF A HOMOGENEOUS SYSTEM

Currently, the food industry of our country faces the task of increasing production, obtaining high quality products and preserving them. The solution of these problems is possible through the use of innovative technologies and equipment. The problem of food preservation and obtaining high nutritional value can be solved by developing the latest technologies for processing and drying of bulk agricultural raw materials used for human consumption. The implementation of innovative technologies is determined by the use of new elements and equipment. Analysis of the development of technologies used for drying agricultural raw materials has shown that plants that operate on the principle of converting electrical energy into energy of infrared radiation have significant advantages and a wide range of uses. The technology of infrared drying of wet products allows to use almost 100% of the energy supplied to the product and significantly reduce the duration of processing and drying. This technology is highly effective at a temperature of 40 ... 60 ° C. With such drying, the product is stored as much as possible, cell membranes are not destroyed, vitamins are stored. At the same time, infrared radiation, which has a sterilizing effect, makes these products suitable for long-term storage. The analysis of literature sources is carried out in the work and the necessity and possibility of creation of new designs of dryers with use of infrared influence on a product and vibration fluctuations of the working container for intensification of drying process is substantiated. The proposed calculations to determine both the time of the product in the processing chamber and the height of the layer will allow to develop an adaptive control scheme for the drying process in the fluidized bed, in devices with infrared heat supply and thus affect the quality of dried products.

Experimental and numerical optimal design of a household solar fruit and vegetable dryer

In the present study, a low-cost solar fruit and vegetable dryer was designed, constructed, and tested for small-scale production, especially in households. An optimizing procedure was performed to convert a typical widely-used direct cabinet dryer into a new indirect dryer using experimental data and numerical simulations. Several well-designed experiments accompanied by CFD simulations using finite volume method were carried out. It was concluded that the proposed conversion procedure could be achieved utilizing a blackened absorber plate, an air circulating unit, and a honeycomb air manifold. The drying capacity of the dryer could be increased by more than 50% in comparison with the direct type by adding a new tray to the optimized dryer. The thermal efficiency of the proposed solar dryer was estimated 16.4%, indicating that the desirable energy performance of the dryer was superior to some available designs of solar dryers. Besides, it was observed that the proposed numerical approach was able to produce a reliable qualitative and quantitative insight into both the thermal and fluid mechanical behavior of the dryer. Finally, it was claimed that not only was the developed apparatus suitable and efficient for the household usage, but also the optimized version of the dryer could be inspiring for those who are currently using typical direct cabinet dryers to convert their dryers into indirect ones.

Classification of Convective Drum Dryers (Survey of Patents)

A classification of convective drum dryers of bulk materials used in chemical and food enterprises as well as enterprises that work with construction materials is proposed. A critical survey of the most characteristic designs of convective drum dryers developed by designers and inventors from the leading countries of the world is performed.

JUSTIFICATION OF CONSTRUCTION-TECHNOLOGICAL PARAMETERS OF INFRARED VIBRATION DRYER

The search for resource-saving and environmentally friendly technologies and technical solutions in the production of food products should occur through the development and development of new analytical methods and constructive measures, which will lead to progress in this field not only in our country but also abroad. The efficient use of processing facilities has always been characterized by its high level of mechanization. Drying is one of the most widespread technological operations in various industries of processing and food production, in particular in the preservation of raw materials. Prospects for the development of drying technologies include reducing energy costs for moisture extraction; improving the quality of dried products; development of highly efficient universal equipment; ensuring the environmental safety of drying plants. When studying different physical phenomena in the process of vibration drying, two methods of research are used, which allow to obtain quantitative regularities. In the first method is used experimental study of specific properties of a single phenomenon, in the second - based on a theoretical study of this problem. The advantage of the experimental research method is the reliability of the obtained results. The analysis of literature sources is carried out and the necessity and possibility of creation of new designs of dryers using infrared influence on the product and vibrational vibrations of the working container for intensification of the drying process is substantiated. The proposed design of an experimental laboratory drying unit for drying granular and granular materials in a vibrating boiling layer allows to identify patterns of changes in the parameters of the drying process, to obtain data to optimize the process and to develop a method of engineering calculation of devices for infrared drying.

Исследование влияния геометрических характеристик аппаратов с псевдоожиженным слоем на технологические параметры процесса сушки

Studies on the influence the fluidized bed apparatus geometrical characteristics on the technological parameters of the drying process. Algorithm and program of calculating tabular processor Microsoft Excel has been developed. Modeling results in the form of graphical dependencies, characterizing the influence of ratio of apparatus for technological process parameters are presented. Trend of energy consumption with reduced height of the separation space apparatus that taken into account in the development of new energy-efficient designs of dryers is installed.

FERROMAGNETIC MATERIALS USE FOR PROVIDING THE NECESSARY THERMAL MODE OF PROCESSING EQUIPMENT (REVIEW)

A new approach to providing the necessary temperature of technological equipment of various industries, in particular, chemical, food, microbiological, heat and power, and therefore a stable thermal mode of processing the flows of substances and materials that are in the specified equipment is proposed. It has been proposed to make working bodies and elements of equipment in contact with the flows of the substances and materials being processed from magnetic material with a phase transition temperature of the second type (Curie point), which corresponds to the temperature of the technological process. The designs of tubular heat exchangers, dryers, packed and disc mass transfer columns, separators, equipment for the processing of thermoplastics (extrusion head, static mixers, worm extruder), as well as bulk feeder are considered. Bibl. 19, Fig. 15.

Perbaikan Desain Mesin Pengering Kopra Sistim Tungku Vertikal: Upaya Produksi Kopra Berdaya Saing

Implementation of this research has been carried out in the copra small industries "Bangun Mandiri" inKupang and aim to expand inter island marketing as one of community welfare. Outputs and outcomes are achieved suchas improving quality and quantity of white copra products through improved designs of multi-functional vertical furnacesystem copper dryers, especially in-house improvements, door frames, outer boxes and fireplaces as well as increasedcapital investment in the form of oven machinery; an increase in sales turnover of 30%; conducting Lab-scale researchfor possibility consuming dry coconut shells that have been patented as an additive of copra-scented foods/drinks andexpansion of marketing area through Pentahelix's partnership to accelerate inter island marketing. Measurable outcomeis to produce oven machine with complete design, also publication on scientific journal. In the future it is expected thatthe SMEs can further focus to quality control by involving academics or local government. To wake up consumerconfidence is also required efforts of local academics to periodically strive for program assistance activities andproduction management to make a teaching factory so that Pentahelix collaboration is established to produce smallindustries areas with highly competitive and prosper to the middle/lower communities and alleviate poverty, especiallykopra.