MODELING AND SIMULATION OF DEEP-BED GRAIN DRYERS

Maize is one of the most important economic crops in the world. The integrity of maize grains directly affects the economic value of the maize as a main commodity that depends on the percentage of grains broken (POGB) in mechanized harvesting. Decreasing grain processing breakage is key to achieving mechanical harvesting with high quality. It is difficult to ensure a low POGB, because it depends on different maize varieties, their moisture contents, threshing devices and harvester working speeds. In this paper, the effects of these factors on the POGB are investigated when the working speed of the harvester is 1.0 m·s−1, 1.5 m·s−1 and 2.0 m·s−1, respectively. The different threshing forms, including tangential-axial-flow (TAF), axial-flow with nail-tooth (AFN), axial-flow with rasp bar in big space (AFRBBS) and axial-flow with rasp bar in small space (AFRBSS), are summarized. The POGB of TAF was 5.4% and it was the lowest of four threshing devices when the working speed of the harvester was 1.0 m·s−1, which was suitable to thresh maize at a low working speed. Maize Demeiya No. 1 (DMYN1), XianDa205 (XD205), Demeiya No. 3 (DMYN3) and Hayu189 (HY189) were harvested at different harvester working speeds, and the POGB of maize DMYN1 was the lowest among the four maize varieties. The POGB increased with increases in the working speed of the harvester and the moisture content of the maize grains. The POGB reached a minimum value of 3.5% when maize XD205 with the lowest moisture content was harvested. The results can provide a reference for choosing the maize variety, its moisture content, the threshing device and the working speed of the harvester for decreasing grain processing breakage.

A method of determining the moisture content of bulk wheat grain

The paper analyzes the control of regime parameters during grain drying in grain dryers. It has been established that direct monitoring of the heating temperature of grain and its humidity in the dryer column in the grain layer is complicated by the uncertainty of sensor readings placed in the layer, which is caused by a significant difference in the heating temperature of the grain as a thermolabile material and a high-temperature heat carrier. The work considers various methods of preventing fire-hazardous situations and deterioration of grain quality as a result of its overheating by traditional methods by mechanical sampling of grain from a column and measuring its temperature and humidity using dielectric, conductometric or microwave methods of measurement. In order to determine the heating temperature of the grain indirectly by the temperature of the spent drying agent, an installation has been developed. The results of its production tests, the prototype design and technical characteristics are presented. Additional production studies have been carried out to determine the change in the moisture content of grain during the drying process in the grain dryer columns by an indirect method based on the relative humidity of the spent drying agent, as well as laboratory tests on the created testbed. The studies were carried out on wheat grain, grain mixture of wheat and barley, and sunflower seeds. The studies have shown high convergence of results in temperature and good convergence in grain moisture. According to the results of joint mathematical processing of the results of production and laboratory tests, regression equations were obtained for calculating the heating temperature and grain moisture during the drying process using the parameters of the spent drying agent: temperature and its relative humidity.

Abstract. Using the right equilibrium moisture content (EMC) relationship is critical for implementing successful aeration strategies and for determining the safe storage moisture content of grains and oilseeds. The oil content of sunflower seeds substantially affects the moisture equilibrium relationship, implying that a specific set of model parameters for each oil content range should be obtained. To overcome this practical limitation, the Enhanced Halsey model was developed incorporating a new parameter (D) to characterize the effect of oil content on the original Modified Halsey model. The constants A, B, C, and D of the model were obtained for a wide range of temperatures, moisture and oil contents. The simplicity of the Enhanced Halsey model and the possibility of adapting EMC as a function of oil content make the Enhanced Halsey model valuable for engineering applications (e.g., aeration controllers) and for predicting the safe storage moisture content of seeds with different oil contents, such as sunflower. Keywords: Composition, Grain, Isotherms, Oilseed, Relative humidity, Sorption, Storage quality.

The moisture content of grain is one of the most important factors determining quality, grade, and price and affecting the physical appearance such as the morphology and color of grain kernels. The objective of this study was to evaluate the correlation between moisture content and image characteristics of corn kernels. A simple and inexpensive machine vision system was set up to obtain images and weights of individual kernels of four varieties of corn. The corn kernels were dried from 32% to 12% (wet basis) moisture at low temperature. A total of 23 morphological and 24 color features were extracted from the individual kernel images. Four optimized feature sets (morphological, color, morphological-color, and weight-morphological-color) were used to fit moisture content using a stepwise linear regression. The coefficient of determination (R2) of the linear regression improved considerably with the combination of morphology, color, and weight. The best results, with an R2 of greater than 0.96, were achieved using the optimized weight-morphological-color set for all corn varieties. The results indicate that the machine vision technique proposed in this study has the potential for rapid measurement of grain moisture content in the industry.

Günümüzde tahılların nem içeriğini belirlemede elde taşınabilen birçok farklı tip portatif nem ölçüm cihazlarının piyasada yaygın bir şekilde kullanıldığı görülmektedir. Bu cihazların doğruluk ve hassasiyetlerinin belirlenmesi ve bu değişkenler üzerindeki etkili faktörlerin araştırılması, cihazların kalibrasyonu ve performanslarının artırılmasına önemli oranda katkı sağlayacaktır. Bu çalışmada, Türkiye piyasasında yaygın olarak kullanılan bazı tahıl nem ölçüm cihazlarının, tane mısırın farklı nem ölçüm aralıklarındaki doğruluk ve hassaslık dereceleri araştırılmıştır. Bu amaçla, üç farklı ticari nem ölçüm cihazı (KETT PM-450 Dökmeli, Wile-55 Sıkmalı, Pfeuffer HE Lite Kırmalı) tane mısırın farklı nem içeriği aralıklarında (%11-12, %16-17, %19-22, %23-25, %27-29 ve %30-31y.a.) denenmiştir. Bu ölçüm cihazlarından elde edilen verilerin doğruluk ve hassaslık dereceleri, referans fırın yöntemi kullanılarak test edilmiştir. Çalışma sonuçları, tane mısırın farklı nem içeriği seviyelerinde aletlerin doğruluk ve hassasiyet derecelerinin farklı olduğunu göstermiştir. Tane mısırın %11-31 nem içeriği aralığındaki yapılan ölçümlerde PM 450 cihazının ölçüm değerleri ile referans fırın ölçüm değerleri arasındaki en düşük fark, başka bir ifadeyle cihaz ölçümlerinin en doğru olduğu ürün nem içeriği aralığı % 21-23 (y.a.) olarak belirlenirken, Wile 55 ölçüm cihazının ölçümlerinin en doğru olduğu ürün nem içeriği aralığı % 14-15 (y.a.) ve Pfeuffer HE Lite Kırmalı nem ölçüm cihazında %11-12 olarak belirlenmiştir.

The authors deal with the problem of mite infestation of stored grain in Czechoslovakia, where more than 10% of the grain is infested by Acarus siro L. and Glycyphagus destructor (Schr.). The methods of mite control hitherto used (fumigants CH3Br, HCN, and ALP) were poor and of short duration. Accordingly, the authors investigated the possibility of biological control using the predacious mite Cheyletus eruditus (Schr.). Some observations showed spontaneous biological control, culminating in the complete eradication of the grain mites. The investigation covered eight grain storages. Details are given of the characteristic course of observations in one grain store, and the results of seven other stores are summarized. In three other stores was studied the influence of cleanliness and moisture contents of grain on the development of mites. The authors found that the mites multiplied on uncleaned wheat (16% moisture content), on cleaned wheat (16% moisture content), and on dry, uncleaned wheat (14% moisture content) in the ratio of 100:10:1.Further details are given about two semioperational trials following the introduction of the predacious mite Cheyletus eruditus (Schr.). These trials were generally successful with the complete eradication of harmful mites.The authors report successful results on the introduction of the predacious mite into uninfested grain destined for long-term storage. They discuss 28 experiments with its artificial introduction (25 successful in biological control) and the course of an operational trial which showed good results as well. Experiences and results from semioperational and operational trials form the basis of a set of technological principles as a guide to practice. It is recommended that the predacious mite be collected from natural biotopes where complete eradication of harmful mites has already been completed. For successful results, the authors recommend artificial introduction in spring or autumn (temperature 5–10 °C) on the surface of grain in the proportion 1:100 to 1:1000 (Cheyletus eruditus Schr.: Acarus siro L. + Glycyphagus destructor Schr.).

Introduction . The widespread use of polyethylene sleeves worldwide has led to their application in various sectors of the national economy. For example, in the agro-industrial complex, polyethylene sleeves are an integral part of the modern method of storing crop products in the field. During the practical application of this storage method in Russia, farmers encountered various problems during their operation, including one of the main ones, namely a violation of the sleeves' tightness. Materials and Methods. The study focused on a non-stationary method of storing crop products in polyethylene bags (silo bags). The research methods included field observations conducted in the Central Federal District during the 2015–2023 agricultural seasons. Surveys of sites for the placement of grain-filled polyethylene bags were conducted over a nine-month period (summer, fall, and winter). Parameters studied included the moisture content of crop products and the degree of damage to the silo bags. Result s. A classification of processes for depressurizing polyethylene bags containing grain during storage is proposed (authorized and unauthorized). The main causes of unauthorized depressurization of silo bags have been identified: improper operation of silo bags at the production site; and the harmful effects of rodents and birds. It has been found that the baseline moisture content of the commercial product influences unauthorized depressurization of silo bags, as their greatest degree of storage damage was detected in grain with moisture contents up to 13.0%. It was established that the cause of grain moisture changes during storage is depressurization of polyethylene bags. Moreover, the nature of the depressurization affects the rate of increase in the grain's moisture content. The nature of damage to silo bags and polyethylene sleeve housings was determined, and the degree of damage (I-III) was established. Conclusions . The results of long-term field observations allowed us to identify the main causes of unauthorized depressurization of silo bags during storage of plant products. It was found that season and relative humidity influence changes in the overall moisture content of grain during storage. It was found that if unauthorized depressurization occurred in summer or winter, when precipitation is lowest, the change in grain moisture content is insignificant.

One of the most perspective directions of intensification of heat and mass transfer in the processes of drying plant materials and increasing the energy efficiency of drying plants is the application of a vibration field for mixing grain material while moving in the drying chamber. The analysis of existing vibration installations has revealed that the most promising is the usage of vibratory grinding chambers with spatial circulation of material for the implementation of grain heat treatment, in particular drying. As a result, it is proposed to use the proven element base of a vibratory mill as a working body of which grinding chambers with spatial circulation of the load are used. The article presents the structural and technological scheme of a vibratory thermal drying unit, the structural parameters of the unit, and a mathematical description of the grain drying process. The obtained differential equations constitute a mathematical model of the nonstationary process of continuous drying of grain material and determine the change in time, parameters of grain and steam-gas mixture at the outlet of the grain drying chamber. The constructed mathematical model of the drying process makes it possible to determine the modes of heating and dehydration of grain material during circulation in a vibrating chamber with a conductive energy supply and partial vacuuming of the chamber, to expand the technological capabilities of the "vibrating mill" type installations. The graphical dependences of the temperature and moisture content of grain over time, the data for which were determined experimentally, are presented when a monolayer of grain of mass m is heated on a heating surface of area F at a stabilized surface temperature θn. In this work, the kinetics of drying and heating of grain were obtained, which were used to calculate the parameters of the vibrothermal drying unit. Also, using the results of the experiments, the performance indicators of the vibration dryer created on the basis of the grinding chamber of the vibrating mill were determined.

Barley: Effect of airflow reversal on fixed bed drying

The applications of computer vision system and tomographic radar imaging for assessing physical properties of food

The present work makes use of experimental data for real part of microwave complex permittivity of spring oats (Avena sativa L.) at 2.45 GHz and 24 °C as a function of moisture content, as extracted from the literature. These permittivity data were individually converted to those for solid materials using seven independent mixture equations for effective permittivity of random media. Moisture dependent quadratic models for complex permittivity of spring oats (Avena sativa L.), as developed by the present group, were used to evaluate the dielectric loss factor of spring oats kernels. Using these data, seven density—independent permittivity functions were evaluated and plotted as a function of moisture content of the samples. Second and third order polynomial regression equations were used for curve fittings with these data and their performances are reported. Coefficients of determination (r2) approaching unity (∼ 0.95–0.9999) and very small Standard Deviation (SD) ∼0.001–8.87 show good acceptability for these models. The regularity in the nature of these variations revealed the usefulness of the density—independent permittivity functions as indicators/calibrators of moisture content of spring oats kernels. Keeping in view the fact that moisture content of grains and seeds is an important factor determining quality and affecting the storage, transportation, and milling of grains and seeds, the work has the potentiality of its practical applications.

In a study on optimum time of harvesting of rice (Var. Jagannath), It was found that, the moisture content in grains decreased at the rate of 0.583% per day, reaching 15.93% at harvesting. The crop harvested at 22% grain moisture content gave the maximum yield. The grains attained physiological maturity at 36 days after heading. Thirty three to 39 days after heading is the optimum time of harvesting of rice (Var. Jagannath).

A simple, low cost instrument that measures impedance and phase angle was used along with a parallel-plate capacitance system to estimate the moisture content (MC) of six types of wheat. Moisture content of grain is important and is measured at various stages of their processing and storage. A sample of about 150 g of wheat was placed separately between a set of parallel plate electrodes and the impedance and phase angle of the system were measured at frequencies 1 and 5 MHz. A semi-empirical equation was developed using the measured impedance and phase angle values, and the computed capacitance, and the MC values obtained by standard air-oven method. Multi Linear Regression (MLR) method was used for the empirical equation development using statistical software. In the present work, a low-cost impedance analyzer designed and assembled in our laboratory was used to measure the impedance and phase angles. MC values of wheat samples in the moisture range of 9% to 25%, not used in the calibration, were predicted by the equations and compared with their standard air-oven values. For over 97% of the samples tested from the six varieties of wheat, the predicted MC values were within 1% of the air-oven values. This method, being nondestructive and rapid, will have considerable application in the drying and storage processes of wheat and similar field crops.

Rice is a very important item of food and commerce in Sierra Leone and so information o n the quality of available rice grains can serve as a useful indicator for the technical status and level of competitiveness in the local rice industry . During this study a n objective evaluation was conducted to measure and characterize the quality of rice grains available in the local markets of Sierra Leone. A total of 315 randomly selected rice samples from 45 markets selected from the four major cities of Sierra Leone (Makeni, Bo, Kenema and Freetown, representing urban communities from the northern, southern, eastern and western parts of the country , respectively ) were evaluated. Quality evaluation involved measurement of moisture content, number of paddy (unmilled rice kernels) in 1 kg of milled rice and other quality factors normally used for the grading of milled rice. Rice samples were then graded based on criteria adapted from the Philippines Rice Grading Standards for milled rice grains. The results showed that the quality of all grain samples evaluated was generally poor, with 63.2% of the samples failing to meet the criteria set for Grade III rice quality ( meaning that the quality level was worse than grade III ) . Quality measures obtained for imported samples appeared to be superior to that obtained for the local samples in terms of higher proportions of superior grades (grade II or better ) . Comparison of measures of grading factors revealed that among the four cities considered in this study, grains from Kenema were of the lowest quality . Further examination of grade limiting factors revealed that the most critical factors responsible for poor quality outcomes in grain sample were (i) the number of paddy in 1kg of milled rice and (ii) the moisture content of grains . The study provided quantitative measures of the quality status of rice grains available in Sierra Leone , as well as a means of identifying the major binding constraints to rice grain quality, in terms of the grade limiting factors. It is speculated that t he low quality of rice grains observed in this study could be the result of avoidable quality defects that may be linked to an undeveloped national system for rice milling and handling .