scholarly journals Thermokinetics of Brown Coal during a Fluidized Drying Process

Energies ◽  
2020 ◽  
Vol 13 (3) ◽  
pp. 684 ◽  
Author(s):  
Zbigniew Plutecki ◽  
Paweł Sattler ◽  
Krystian Ryszczyk ◽  
Anna Duczkowska ◽  
Stanisław Anweiler

This paper presents the results of research describing the thermokinetics of brown coal’s (lignite) drying process in a fountain-bubble fluidized bed dryer. The drying medium was atmospheric air of a variable temperature in subsequent tests, which ranged from 27 to 70 °C. This paper presents the results of many experimental studies for two different types of brown coal: xylite, from the Bełchatów mine, and earth, from the Turów mine. The two types of brown coal are used to assess different sized coal particles and different air drying temperatures. The functions parameterizing the moisture content of dried coal at different air drying temperatures at any given time are also presented.

Foods ◽  
2020 ◽  
Vol 9 (1) ◽  
pp. 101 ◽  
Author(s):  
Senadeera ◽  
Adiletta ◽  
Önal ◽  
Di Matteo ◽  
Russo

Drying characteristics of persimmon, cv. “Rojo Brillante”, slabs were experimentally determined in a hot air convective drier at drying temperatures of 45, 50, 55, 60, and 65 °C at a fixed air velocity of 2.3 m/s. It was observed that the drying temperature affected the drying time, shrinkage, and colour. Four empirical mathematical models namely, Enderson and Pabis, Page, Logarithmic, and Two term, were evaluated in order to deeply understand the drying process (moisture ratio). The Page model described the best representation of the experimental drying data at all investigated temperatures (45, 50, 55, 60, 65 °C). According to the evaluation of the shrinkage models, the Quadratic model provided the best representation of the volumetric shrinkage of persimmons as a function of moisture content. Overall, higher drying temperature (65 °C) improved the colour retention of dried persimmon slabs.


Today many industries now use the dryer as a part of grain-drying process even during wet and dry seasons. This helps in reducing spoilage and wastage of paddy. Mostly the available industrial dryers are expensive to purchase and to maintain its smooth functioning. This study therefore is a step to design a simple Plug flow fluidized dryer that can lead to introduce small scale dryers to paddy process industry. The Plug flow fluidized bed dryers are designed and fabricated in this study consists of the drying chamber, hot air distributer plate, hot air inlet and exit system, paddy entry and exit system, fluidization chamber unit with temperature control unit and the centrifugal fan. The evaluation of dryer is based on drying time and reduction in moisture content and outlet temperature of paddy on quality parameters. Dryer dimensions are very important to analyze heat and mass transfer analysis of the Plug flow fluidized bed drying process of paddy grains. It was found d that heat and mass transfer properties of paddy grains in fluidized bed dryer was decreases as the time of drying passes and very rapid at the start of drying. The model present here predicts about dryer dimensions along safe zone of rough rice moisture content with other parameters. Simulation results show a good agreement between the simulation model and the existing simulation models


Author(s):  
Anatolii Spirin ◽  
Ihor Tverdokhlib ◽  
Ihor Kupchuk ◽  
Julia Poberezhets

Shortage of quality feed significantly slows down the production of livestock products in Ukraine. One of the ways to overcome the crisis in the production of feed is the use of new high-energy feed, including the products of fractional processing of alfalfa. For the successful implementation of the skin type of feed, including the products of fractional processing of alfalfa, there should be an opportunity to create their reserves, feed should be canned for successful storage. The best way to preserve food is to dry it. Energy efficiency of the drying process, ie loss of nutrients, energy costs for the implementation of the process, etc. It depends on the method and its mode parameters. In this case, it is proposed to carry out the drying process in a thick layer of alfalfa pulp by active ventilation with heated air. To determine the rational parameters of the process, such as layer thickness, air flow, drying time and patents to conduct theoretical and experimental studies. Alfalfa pulp, like most wet plant materials, belongs to the capillary-porous bodies. The drying blood of these bodies has two distinct periods: constant and decreasing speeds (or the first and second drying periods). The moisture content of the material at which the transition from the first to the second period is called critical. As a result of theoretical research has obtained a dependence that determines the total duration of the drying process on a number of parameters, including initial, critical, equilibrium and final moisture content. To determine these coefficients, as well as to check the adequacy of the obtained dependence, experimental studies were conducted on a special installation. The main elements of the experimental setup are a fan, electric heater, containers with mass, shut-off, control and measuring equipment. According to the results of experimental research, graphical dependences of drying speed and process duration on regime parameters are obtained.


2017 ◽  
Vol 36 (6) ◽  
pp. 664-672 ◽  
Author(s):  
Kenichi Arima ◽  
Yoshihiko Tsuchiyama ◽  
Tetsuya Sawatsubashi ◽  
Masaaki Kinoshita ◽  
Hiromi Ishii

2016 ◽  
Vol 24 (0) ◽  
Author(s):  
Djeison Cesar Batista ◽  
José Tarcísio da Silva Oliveira ◽  
Rená Porto Pizetta ◽  
Vinicius Munaldi Lube

ABSTRACT The determination of moisture content gradients is one of the most important steps for assessing the quality of wood drying. The general aim of this work was to study the quality of air-dried teakwood boards according to the gradients of moisture content in thickness and length. Six representative boards (40 × 180 × 2,300 mm) were sampled from a stack air-dried under shelter, divided into 30 equal parts in length and measured with a resistance moisture meter, resulting in four treatments: two depths (1/4 and 1/2 thickness) and two surfaces (inner and outer) of measurement. As main results, we can conclude that the air-drying quality can be considered good, mainly for two reasons: i) the average moisture content gradients in thickness were comparable to those reported in literature for kiln-drying of less thick boards; ii) the range of average moisture content among boards (2.5 p.p.) was satisfactory for a drying process carried out without environment control. Length moisture content gradient was completely different from that reported in literature, in which no board tops had smaller moisture content than the parts comprehended in between the tops.


Author(s):  
Luna Shrestha ◽  
Roberto Moscetti ◽  
Stuart Crichton ◽  
Oliver Hensel ◽  
Barbara Sturm

Organic dried apples are common snacks fulfilling functional as well as nutritional aspects. However, appearance of dried slices does not always satisfy consumer requirements, thus, improvements are needed. In this study, partial least squares (PLS) regression models were successfully developed to monitor changes in colour and moisture content in apple slices during the drying process over the Vis/NIR spectral range. The regression vector analysis results suggested that features at 580, 750 and 970 nm are better for predicting moisture content, while 580 and 680 nm allow to measure the (a*/b*) colour ratio.   Keywords: Drying; Dried apple slices; Moisture content; Colour; PLSR modelling


Agrotek ◽  
2018 ◽  
Vol 3 (1) ◽  
Author(s):  
Abadi Jading ◽  
Paulus Payung ◽  
Eduard Tethool ◽  
Reniana Reniana

<em>Sago starch drying done to reduce the moisture content in starch, so as to increase the shelf life and quality of dry starch. The drying process should be done while maintaining the physicochemical properties of sago starch. The research goal is to find the proper drying techniques to produce dried sago starch has a moisture content corresponding to the Indonesian National Standard (SNI). The experiments were performed three times with variations in temperature 40<sup>o</sup>C, 50<sup>o</sup>C, and 60<sup>o</sup>C. The moisture content of sago starch obtained at temperatures 40<sup>o</sup>C, 50<sup>o</sup>C, and 60<sup>o</sup>C, respectively 13.75% wb, 13.50% wb and 13.42% wb. Drying time at drying temperature of 40<sup>o</sup>C, 50<sup>o</sup>C, and 60<sup>o</sup>C respectively 5.5 hours, 4 hours, and 3 hours. A good drying sago starch using cross flow fluidized bed dryer at a temperature of 60�C ie, it reduces the moisture content more quickly in accordance with the SNI, and gelatinization does not occur during the drying process.</em>


2012 ◽  
Vol 8 (3) ◽  
Author(s):  
Yoshiki Muramatsu ◽  
Eiichiro Sakaguchi ◽  
Takahiro Orikasa ◽  
Akio Tagawa

Abstract The drying characteristics and volume changes of scarlet runner beans were measured under various conditions to obtain useful basic information for the optimum drying method and conditions. The sample was dried using two drying methods: hot air drying and vacuum drying. The measured changes in moisture content of the sample with the hot air drying process were in good agreement with the exact solution of the infinite plane sheet model. The estimated diffusion coefficients were 3.8×10 -7 -7.4×10 -7 (m 2 h -1) for hot air drying and were related to absolute temperature by an Arrhenius-type equation. The hull of the scarlet runner bean is hard and thick, and the drying rate of the sample was much slower than that of other beans. To establish an efficient drying method without the quality loss, the vacuum drying characteristics of the sample were measured at several levels for temperature and initial moisture content. For the vacuum drying process, an exponential model could be used to estimate the changes in moisture content of the sample. The values of diffusion coefficient for vacuum drying were approximately twice as much as the values of diffusion coefficient for hot air drying at the same temperature. The effects of drying method, temperature, and initial moisture content on the sample quality were investigated, and the optimum drying method and conditions for scarlet runner beans were proposed. Volumetric changes in the sample were determined by measuring particle density. The specific volume of the sample was represented as a linear function of moisture content.


Author(s):  
N. Zanko ◽  
◽  
T. Gaidai ◽  
S. Stepchenko ◽  
N. Nilova

Aim. Investigation of the influence of natural factors on the quality of grain drying in a grain modular dryer. Methods. Experimental studies in operational conditions and graphical modeling of dried grain moisture depending on natural factors. The results. The change in the environmental conditions causes a certain influence on the return of the spent waste dryer to the environment and the processes of drying the grain in it. This causes the production of undried grain and reduced drying efficiency. The influence of natural factors - temperature and humidity, atmospheric pressure and wind speed on the humidity of corn grain during its drying with a single-module grain dryer has been studied. The output of the refrigerant with moisture vapor is carried out through the perforated panels of the dryer circuit and at the same time experiences some resistance from atmospheric pressure. The results show that the reduction of atmospheric pressure helps to reduce the resistance for the exit of the coolant through the surface of the dryer housing. As a result, the coolant in the chamber is more efficiently spent on the grain drying process. This is evidenced by the simultaneous decrease in pressure and humidity of the dried grain The dryer is also affected by the wind: its body experiences cooling, and the drying temperature and drying conditions of the grain deteriorate. Thus, during the research period, the wind speed decreased from 5,3 m / s to 4,4 m / s, and the humidity of the dried grain decreased from 15,2 % to 13,9 %. That is, the reduction of the effect of wind on the surface of the dryer has a positive effect on the drying process of grain. The ambient air is characterized by the moisture present in it. Its reduction in atmospheric air promotes better moisture yield from corn grain and the "filling" of this air moisture: the humidity of the dried grain decreases. The positive temperature of the atmospheric air causes additional thermal action on the dryer and the drying process in it. In this case, the heat supplied to the working chamber of the dryer is more productively used for the drying process: in accordance with the increase in atmospheric air temperature, the humidity of the dried grain decreased from 15,2 % to 13,9 %. Based on the results of experimental studies, graphical dependences of the humidity of dried corn grain on humidity, pressure, temperature and velocity of atmospheric air are constructed. The grain harvester is a system adapter for Conclusions. Conclusions. The process of grain drying and the moisture content of the resulting dried grain of modular grain dryers depends on the influence of objective natural factors. These include, in particular, the weather conditions during the operation of dryers. With an increase in humidity, pressure and air velocity, the quality of drying deteriorates: when the moisture content of the grain decreases from 18,5 ° C to the regulated 14 %, with a single pass through the dryer, the moisture content of the dried grain exceeds the regulated one and vice versa. Drying grain in conditions of positive ambient air temperatures, especially at an air temperature of more than 21 °C, is most favorable for obtaining grain with a moisture content that is significantly less than 14 % and vice versa. Low wind speed, dry and warm atmospheric air with low pressure contribute to the production of dried grain with regulated humidity. For the maximum elimination of the unfavorable influence of natural factors on the quality of operation of modular dryers according to the criterion of the moisture content of dried grain in the conditions of the forest-steppe zone of Ukraine, it is advisable to carry out the drying process in the period from late September to early October.


2012 ◽  
Vol 490-495 ◽  
pp. 3074-3078
Author(s):  
Chun Shan Liu ◽  
Wen Fu Wu ◽  
Jia Song ◽  
Ya Qiu Zhang ◽  
Jun Xing Li ◽  
...  

In order to solve the drying problems in the deep-processing of pepper, peppers were dried through blanching pre-treatment and hot-air drying process. Orthogonal test designs were carried out to investigate factors influencing the quality and moisture content of pepper. The results showed that the whole drying process was a reduction speed drying, hot-air temperature and wind speed have significantly affected on the drying rate of pepper, but the impact of hot-air temperature was more prominent than wind speed; hot-air temperature was found to be the primary parameter to affect the quality of the pepper, wind speed was the secondary one and followed by packing thickness; drying time was found to be the primary parameter to affect the moisture content of the pepper in the drying process, the best drying conditions were as follows: wind temperature was 80°C, wind speed was 10 m/s, packing thickness was 80 cm, drying time was 12 h after 100°C steam blanching pre-treatment


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