Mathematical Modeling of the Process of Operation of the Drying Chamber of a Tower Grain Dryer With a Suction Air Flow

Author(s):  
Viktor Shvidia ◽  
◽  
Serhii Stepanenko ◽  

In the article, a drying scheme in a tower grain dryer has been developed, equations for the conservation of energy and material balance for grain, equations for mass transfer and heat transfer between the drying agent and grain have been drawn up. On their basis, analytical dependences of changes in the temperature and moisture content of grain, moisture content and temperature of the drying agent along and in the width of the drying channel were obtained, depending on the operating parameters (the value of rarefaction in the drying channel, the speed of grain movement along the drying channel, the speed of movement of the drying agent, the initial temperatures of the grain and drying agent, initial moisture content of grain, as well as initial moisture content of drying agent). Their analysis facilitates the work in choosing the optimal mode. The developed analytical dependences of changes in the main drying parameters (moisture and temperature of grain, moisture content and temperature of the drying agent) along the length and width of the drying channel in tower dryers with suction air flow make it possible to link the main operating parameters, which facilitate the choice of rational drying modes.

2017 ◽  
Vol 7 (1) ◽  
Author(s):  
S. Syahrul ◽  
M. Mirmanto ◽  
S. Romdani ◽  
S. Sukmawaty

Grain processing does not meet the actual grain harvests. This is due to the unsuitable drying process. Milling grain entrepreneurs and farmers in Indonesia are currently conducting a drying process under the sun. Based on the National Standards Body (BSN), grain moisture content must be at 14% to maintain the grain at high qualities. The purpose of this study is to determine the effect of velocity and grain mass variations on drying times. The grain used in this study contains an initial moisture content of 22% ± 0.5%. The grain is dried by inserting it into the drying chamber and varying the air velocities and grain mass. The air velocities used are 4 m/s, 5 m/s, 6 m/s and the variations of the grain mass are 1 kg 2 kg and 3 kg. The results show that increasing the air velocity decreases the drying time. On the other hand, when the grain mass is increased, the drying time elevates. The air velocity and mass of the grain that results in the fastest drying time are 6 m/s and 2 kg. The time required for achieving the water content of 13.6% is 30 menit. At the air velocity of 4 m/s, and the grain masses of 1 kg, 2 kg, and 3 kg, to achieve moisture contents of 13.4%, 13.5% and 13.4% the drying time needs 50 minutes.


2018 ◽  
Vol 12 (4) ◽  
pp. 29-34
Author(s):  
S. A. Pavlov ◽  
T. F. Frolova

Mine and column grain dryers are a fairly complex object of control in the production line. The process of grain drying is characterized  by a large number of parameters, quantitatively and qualitatively characterizing the dryer operation. First of all, this includes the criteria of maximum performance and minimum deviations of the moisture content of the dried grain from the standard values. These criteria, as studies show, are interconnected with each other: an increase in the performance П of the dryer leads to an increase in the moisture content of the grain coming out of it, and, conversely, an attempt to reduce the moisture content of grain causes the need to reduce the performance П. (Research purpose) The research purpose is to develop the expression for the transfer functions of the of grain flow control depending on perturbations of the initial moisture content and the maximum grain temperature, as well as to conduct experimental studies. (Materials and methods) The authors have developed simplified mathematical models of moisture perturbation compensation of grain coming in for drying and its heating temperature in a drying chamber by changing the dryer performance on the basis of theoretical-and-experimental studies. (Results and discussion). The authors  have obtained  expressions to control the process performance when the current humidity and temperature change through the dryer performance parameters as a function of grain moisture flow and heat used to grain heating up to an acceptable temperature. Farm tests of developed transition management functions have been implemented for dryer SZT-16 controlled by PLC S7-1200 Siemens and operating in an automatic mode. Tests have been conducted on the “Babachev” farm, Karachev district of the Bryansk region in the process of drying food wheat grain. (Conclusion) It has been confirmed that the dryer performance is determined not only by the rated capacity but also by the deviation of the current moisture content of grain from the specified values and by the ratio of the amount of heat used for evaporating and heating. The dryer performance at constant initial humidity is determined by its rated performance, the maximum specified difference of grain temperatures, as well as the ratio of the amounts of heat used for evaporating and heating.


2018 ◽  
Vol 39 (6) ◽  
pp. 2821
Author(s):  
Wilker Alves Morais ◽  
Osvaldo Resende ◽  
Fernando Nobre Cunha ◽  
Vitor Marques Vidal ◽  
Nelmício Furtado da Silva ◽  
...  

Physical properties of soybean grains present differences as a function of cultivars and moisture content, with the correlation between physical properties. This study aimed to determine the characteristics related to the physical properties of grains with different moisture contents of three soybean cultivars. The experimental design was completely randomized design in a 3 × 6 factorial scheme with three replications, consisting of three soybean cultivars (6266 RSF IPRO, BMX Potência RR, and 14403Z6001) and six grain moisture contents (11, 13, 15, 17, 19, and 21% wb). Soybean grains presented an initial moisture content of 11.0, 11.0, and 10.8% wb, respectively for 6266 RSF IPRO, BMX Potência RR, and 14403Z6001. The other moisture contents were obtained by soaking in a BOD chamber maintained at 25 °C and 93% of relative humidity. We assessed volume, roundness, sphericity, surface area, volumetric shrinkage, and volumetric shrinkage rate. The data were submitted to the analysis of variance by the F-test (p < 0.05) and when significant, regression analysis was performed for grain moisture contents and the means of cultivars were compared by the Tukey’s test. Pearson’s correlation analysis was also carried out to represent the linearity between grain physical properties. The cultivar BMX Potência RR obtained the highest results for volume, roundness, sphericity, and surface area. Volume and surface area increased as the moisture content of soybean grains increased; the opposite was observed for roundness and sphericity. A linear increase in volumetric shrinkage was observed as moisture content increased. The values of the correlation coefficients of the linear regression models can be used to describe the relationships between physical properties.


2011 ◽  
Vol 66-68 ◽  
pp. 573-576
Author(s):  
Chun Shan Liu ◽  
Wen Fu Wu ◽  
Jia Yao ◽  
Ya Qin Li ◽  
Chuang Liu

The purpose of this study is to explore the effecting principle in the drying process. The factors such as hot air temperature, hot air flow, drying time on the grain moisture content have been all investigated. Using UD to establish the optimization mathematics model which making the grain dryer moisture content as the goal of the design, making the factors of hot air flow, drying time, air temperature as parameters, with the help of UD to analysis the effecting principle of the drying process parameters on the grain moisture content, some references have been provided to the tower dryer.


2020 ◽  
Vol 51 (3) ◽  
pp. 176-183
Author(s):  
Surachai Hemhirun ◽  
Pracha Bunyawanichakul

After the harvest, the paddy would contain high and unequal initial moisture content, depending on the season and harvest time. As a result, the dehydration was caused by using the dryer while feeding the paddy grain unequal moisture content, the dryer should be properly adjusted to retain the final moisture content as per the rice mill and storage requirements and low specific energy consumption (SEC) were used for the drying operation per one cycle product. The objective of this paper was to study the paddy drying operation by using a continuous cross-flow dryer at a different initial grain moisture content. The research was divided into two steps, the first step began with the drying operation with levels of the initial moisture content 20.0%wb that involved the adjustment of the parameters of an average hot-air temperature 150°C, the speed rotation of an eccentric set of 11.52 rad s–1, the airflow rate 0.016 m3 s–1, and speed rotation of rotary valve 0.21 rad s–1 (approximately feed rate 36 kg h–1), by the application of these parameters, from the obtained results, it was found that grain moisture content of paddy was reduced from 20.0%wb to 14.3%wb as desired, and SEC of 3.60 MJ kg–1 water was evaporated. Then the second step, these parameters were tested in terms of the drying operation that the initial grain moisture content decreased and increased 18.1%wb and 23.0%wb, respectively. The results showed that when the initial grain moisture content decreased, the paddy drying operation reduced the moisture of the paddy until the final grain moisture content became 12.9%wb which was lower than the desired expectation, On the contrary, when the initial moisture content increased, the final grain moisture content became 16.1%wb. This was not sufficient for storage or planting in the next crop year which required re-drying operation as well. Furthermore, the results can be used as reference data and a guideline for small communities in Thailand to appropriate decisions with the drying cost and the value-added tax.


2020 ◽  
Vol 12 (1) ◽  
pp. 24-32
Author(s):  
Usman Usman ◽  
Akhyar Muchtar ◽  
Umar Muhammad ◽  
Nunik Lestari

Grain drying is a process to reduce grain moisture content to certain conditions, so the grain can last longer in storage. The grain dryer model used in this research was Indirect Type Solar Dryer (ITSD). In order to make this dryer can work at night, heating element that used electrical energy from solar panels was added. This energy is a renewable and environmentally friendly energy. This dryer was equipped with a temperature monitoring system and control of the photovoltaic heater. The results of temperature monitoring and voltage sensors to controlling photovoltaic heaters based on validation are categorized as work measurement tools, because they have an error of 0.5% – 2%. Whereas the relay works when the battery voltage is 11 - 10.9 V. This dryer can dry grain to reach a moisture content of 14.90% from initial  moisture content of 48.46%. The drying process lasts for 11 hours, which is 7 hours using solar energy and 4 hours using photovoltaic heaters. The average temperature produced by dryer system during the drying process is 35.28 °C with a drying efficiency of 60.14%.


2008 ◽  
Vol 51 (3) ◽  
pp. 453-456 ◽  
Author(s):  
Javier Alberto Vásquez-Castro ◽  
Gilberto Casadei de Baptista ◽  
Casimiro Dias Gadanha Junior ◽  
Luiz Roberto Pimentel Trevizan

The goal of this work was to evaluate the effect of spray volume on the moisture of the stored grains of the corn and wheat. Two kg of each type of the grain were placed into the plastic bags and sprayed with the theoretical doses of 0, 1, 3, 5, 8, and 10 liters of water / ton of the grain. The grain moisture content was evaluated 24 h after the spray operation by the oven method. The increase in the grain moisture was quadratic and showed the same trend in both the corn and wheat. The grain moisture after spraying 10 L.t-1 showed little increase (0.8 %) as compared to the initial moisture content. Thus, the application of any spray volume as used in this study made no difference for a possible better uniformity in the distribution of insecticide throughout the sprayed material.


2011 ◽  
Vol 367 ◽  
pp. 517-524
Author(s):  
A. F. Alonge ◽  
O. O. Oniya

A solar drying system designed on the principles of convective heat flow, constructed from local materials was employed in drying yam (Dioscorea Alata). A glass collector having an efficiency of about 0.63 was used along with an absorber for absorbing the heat energy. The drying chamber consisted of drying trays. A chimney fitted at the top centre of the drying chamber enhanced airflow. Air passing through the collector heated up and dried the foodstuff in the drying chamber. The latitude of Ilorin is 8.26oN and the collector angle could be varied . 56o C, 41o C and 71o C were obtained as the maximum attainable temperatures for the drying chamber, ambient and collector respectively. Two samples of yam chips, each weighing 1560g and having an average size of 1cm thick, were dried both inside the dryer and outside the dryer within its surrounding. The initial moisture content of the yam was 70.3% (wet basis) and its final moisture content was 9% (wet basis).The result was compared to natural sun drying. It was observed that the drying time was reduced from 52 hours for sun drying to 45 hours for solar drying. The total cost of the construction was 6, 105 Naira.


2014 ◽  
Vol 941-944 ◽  
pp. 1196-1200
Author(s):  
Li Li Zhang ◽  
Chuan Chuan Ma

This paper investigated the influence of operating parameters such as inlet air temperature, compressed air flow rate, concentration of carrier agent and type of carrier on the physicochemical properties of fruit juice powders produced by spray drying.The results indicated that increasing inlet air temperature resulted in the larger size particles with smoothly spherical appearance, and to lower bulk density and moisture content. The bulk density of powders also decreased with increasing carrier agent concentration, decreasing compressed air flow rate. The higher feed flow rate negatively affected process yield and positively influenced moisture content, and occurring the wall deposition easily. Additionally, the anthocyanin retention mainly depends on the inlet air temperature and type of carrier. Moreover, the novel methods and ideas to this problem in the next studies were presented.


2020 ◽  
Vol 9 (1) ◽  
pp. 131-139
Author(s):  
Suherman Suherman ◽  
Hasri Widuri ◽  
Shelyn Patricia ◽  
Evan Eduard Susanto ◽  
Raafi Jaya Sutrisna

In this study, hybrid solar drying of coffee beans was performed, and energy analysis was carried out, to assess the system’s performance, in terms of energy efficiency, compared to solar drying and the open sun drying method. The dryer has three compartments: solar collector for collecting solar radiation, drying chamber, and a Liquid Petroleum Gas burner, which acted as an auxiliary heater to assist the thermal energy. The drying chamber has four trays for placing the dried product. The initial moisture content of coffee beans was 54.23% w.b and was reduced to the final moisture content between 11-12% w.b. The coffee beans dried faster when subjected to the solar hybrid drying method, compared to other methods, with the dryer temperature of 40°C, 50°C, and 60°C. Results indicated that the coffee beans’ drying times varied from 10 to 14 hours. However, at temperature 50°C and 60°C for the 1st tray, the water content was reduced more rapidly compared to the other tray. From the results of this study, we can see the different efficiency of solar collector that shows of 54.15% at variable temperature 60°C for drying time 12:00 to 14:00 p.m for hybrid solar drying and for the solar drying process is 50.07% at the range of drying time 12:00 to 14:00 p.m. Mathematical modelling shows that Page model is the most suitable for describing the coffee beans’ drying behaviour using a hybrid solar dryer. The effective diffusivity values found in this experiment are all in the acceptable range for most agricultural products. ©2020. CBIORE-IJRED. All rights reserved


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