Microwave Drying Characteristics of Soybeans in Single and Variable Microwave Power Density

2017 ◽  
Vol 13 (4) ◽  
Author(s):  
Ruifang Wang ◽  
Lijuan Zhang ◽  
Kun Lei ◽  
Qing Xu ◽  
Wei Tian ◽  
...  
Keyword(s):  
Energy Consumption ◽  
Power Density ◽  
Microwave Power ◽  
Lower Energy ◽  
Microwave Drying ◽  
Drying Rate ◽  
Drying Process ◽  
Drying Characteristics ◽  
Single Power ◽  
Energy Aspects

Abstract Drying characteristics of soybeans under different microwave (MW) processing schemes were studied in regard to energy aspects. For drying in a single microwave power density, the experiments were carried out at a constant MW output power throughout the process. It was found that the drying rate is enhanced together with reduced energy consumption at higher single power density, but the soybean cracking ratio is increased gradually from 2 % to 40 % when the power density was changed from 0.2 W/g to 0.8 W/g. Efforts were made to reach a compromise between the drying rate and dried soybean quality by varying the MW power density in several steps overall the drying process, but soybean cracking occurred at a higher ratio due to the fluctuation of drying rate. Microwave drying of soybeans under the power density less than 0.2 W/g with slow and stable drying rate can achieve the soybean cracking ratio controlled within 5 % and lower energy consumption.

Study on Microwave Drying Process and Drying Characteristics of Sewage Sludge

2013 ◽  
Vol 838-841 ◽  
pp. 2643-2647
Author(s):  
Jin Ping Li ◽  
Meng Yao Li ◽  
Wen Yao ◽  
Ni Wang
Keyword(s):  
Energy Consumption ◽  
Sewage Sludge ◽  
Lower Energy ◽  
Microwave Drying ◽  
Drying Rate ◽  
Municipal Sludge ◽  
Drying Process ◽  
Drying Characteristics ◽  
Pretreatment Time ◽  
Short Time

Combination of oven and microwave and only oven are two ways to study municipal sludge,and it investigates whether different size, microwave drying pretreatment, pretreatment time and oven temperature characteristics have effect on drying characteristics. The results shows that: using microwave to dry sludge need short time, the drying rate is fast, combination of oven and microwave has higher drying rate and lower energy consumption than only oven.

scholarly journals Microwave Drying Characteristics and Drying Quality Analysis of Corn in China

Processes ◽  
2021 ◽  
Vol 9 (9) ◽  
pp. 1511
Author(s):  
Haili Liu ◽  
Haoyu Liu ◽  
Heyun Liu ◽  
Xu Zhang ◽  
Qingchao Hong ◽  
...  
Keyword(s):  
Energy Consumption ◽  
Microwave Power ◽  
Early Stage ◽  
Microwave Drying ◽  
Quality Analysis ◽  
Drying Rate ◽  
Drying Characteristics ◽  
Drying Conditions ◽  
Opposite Tendency

To identify the microwave drying characteristics of corn, microwave drying tests were conducted on corn. By taking the moisture content, drying rate, and drying temperature as indices, this research revealed the effects of different microwave powers and loads on the microwave drying characteristics of corn. Moreover, energy consumption and quality of dried corn were analysed under different drying conditions. The results demonstrate that microwave drying has significant energy-saving effects. The energy consumption by microwave drying is less than 0.3 times that used by electrothermal drying under the same load. Both microwave power and load exert significant influences on drying characteristics. Higher microwave power results in a greater average drying rate, wherein shorter periods of time are required to reach the maximum drying rate and higher temperatures of the corn. However, the load shows the opposite tendency. The smaller the load, the higher the temperature of the corn in the early stage of drying. However, as drying continues, the temperature curve changes significantly, and the temperature rises with the increase in load in the later stage of drying. In consideration of energy consumption and dried quality, the load of corn should be increased as appropriate, and the microwave intensity should be limited to no higher than 0.7 W/g in the experiment.

Calculation of Moisture Content and Drying Rate during Microwave Drying

2013 ◽  
Vol 423-426 ◽  
pp. 746-749
Author(s):  
Samad Khani Moghanaki ◽  
Behnam Khoshandam ◽  
Mohammad Hosein Mirhaj
Keyword(s):  
High Temperature ◽  
Moisture Content ◽  
Microwave Power ◽  
Operating Temperature ◽  
Irradiation Time ◽  
Microwave Drying ◽  
Drying Rate ◽  
Microwave Method ◽  
Drying Process ◽  
Drying Time

Convectional dryerswork at high temperature and usually lead to loss of quality for sensitivebiomaterial products (especially in nutrition). In this way the researchersfound the microwave power more effective and suitable for drying processes. Someof microwave drying advantages include the following: short drying time, highquality of product, low operating temperature, flexibility in producing widerange of products and easier process controlling. The article calculated themoisture content and drying rate during drying process. Microwave power, holdertray speed, dimension of samples, irradiation time were considered; under theseconditions experiments were done and the results show that microwave method hasmore advantages as comparing with convectional methods.

scholarly journals Microwave drying behaviour of tomato slices

2013 ◽  
Vol 31 (No. 2) ◽  
pp. 132-138 ◽  
Author(s):  
S. Çelen ◽  
K. Kahveci
Keyword(s):  
Energy Consumption ◽  
Theoretical Model ◽  
Microwave Power ◽  
Internal Heat ◽  
Internal Heat Source ◽  
Microwave Drying ◽  
Drying Rate ◽  
Drying Time ◽  
Drying Behaviour ◽  
Drying Conditions

The microwave drying behaviour of tomato slices was investigated experimentally to determine the effects of microwave power on the drying rate, energy consumption, and dried product quality in terms of colour, and a theoretical model was proposed to define the drying curves of tomato slices. The experiments performed with the microwave power of 90, 180, 360, and 600 W indicate that the drying time and the energy consumption decreased considerably with an increase in microwave power. The experiments also revealed that the drying rate shows first an increase and then a decrease during drying, and that the colour quality of the product deteriorates significantly with the increase of the microwave power. A theoretical model was developed using the solution of energy equation considering the microwave power as an internal heat source. The electric field strength inside the material was assumed to be dependent on the moisture content and the constants emerging from this assumption were obtained by minimising the sum of squared differences between the theoretical results and experimental data obtained for various drying conditions. The results show that the values proposed for the constants provide a good agreement between the theoretical and experimental drying behaviour.  

Effect of Process Parameters on Quality Properties of Microwave Dried Red Pitaya (Hylocereus costaricensis)

2008 ◽  
Vol 4 (6) ◽  
Author(s):  
Mariam Firdhaus Mad Nordin ◽  
Wan Ramli Wan Daud ◽  
Meor Zainal Meor Talib ◽  
Osman Hassan
Keyword(s):  
Power Density ◽  
Microwave Power ◽  
Color Change ◽  
Sample Surface ◽  
Microwave Drying ◽  
Moisture Loss ◽  
Drying Rate ◽  
Quality Properties ◽  
A Value ◽  
Higher Power

The effect of microwave power density on the microwave drying of red pitaya (Hylocereus costaricensis) was investigated using a small modified commercial microwave. Microwave power density was varied in the range of 5.47 to 19.02 W/g. The ambient, internal sample and sample surface temperatures, and moisture loss were measured during microwave drying at various microwave power densities. The drying rate increased with increasing power density. The temperature profiles rapidly reached their saturation level. The experimental moisture loss data were fitted to the Tang and Cenkowski drying model using a value of residual sum of squares (RSS) to evaluate the goodness of fitting the model. The dried product was analysed to examine the quality such as color, shrinkage, tensile hardness and structure. The results showed that the color change is higher at higher power density and temperature because of the faster browning rate and faster drying rate. The beginning of the color change corresponded closely to the beginning of the falling rate period. The microwave drying also caused the red pitaya to shrink to a greater extent of up to 70% at higher power density because of the faster drying rate. The internal structure also tended to collapse during microwave drying.

Meso-mechanics simulation analysis of microwave-assisted mineral liberation

2015 ◽  
Author(s):  
Qin Like ◽  
Dai Jun ◽  
Yuan Liqun
Keyword(s):  
Energy Consumption ◽  
Microwave Irradiation ◽  
Power Density ◽  
Microwave Power ◽  
Mineral Content ◽  
Crystal Size ◽  
Irradiation Time ◽  
Mineral Crystal ◽  
Microwave Assisted ◽  
Time And Energy

Microwave-assisted crushing and grinding can improve efficiency and reduce energy consumption. This paper takes rock grains with galena and calcite as the research object to establish a two-dimensional computational model through the finite difference software FLAC2D. It analyzes the process and law of mineral boundary failure under microwave irradiation, and assesses the effects of four factors, namely, microwave irradiation time, power density, mineral crystal size, and mineral content, on mineral boundary failure. Results indicate an optimal microwave irradiation period for the rapid failure of mineral boundary. Moreover, irradiation time and energy consumption can be reduced by increasing the microwave power density. However, irradiation time and energy consumption are basically unchanged when the microwave power density is above a certain threshold. Mineral content slightly affects the microwave irradiation time, whereas mineral crystal size significantly affects the microwave irradiation time. In addition, a larger-sized mineral crystal requires less irradiation time and energy consumption to reach the same failure rate. However, irradiation time and energy consumption slightly change when the crystal size is larger than a certain value.

scholarly journals Microwave drying of nickel-containing residue: dielectric properties, kinetics, and energy aspects

2019 ◽  
Vol 8 (1) ◽  
pp. 814-824
Author(s):  
Zhanyong Guo ◽  
Fachuang Li ◽  
Guang Su ◽  
Demei Zhai ◽  
Chenhui Liu
Keyword(s):  
Dielectric Properties ◽  
Arrhenius Equation ◽  
Recovery Process ◽  
Microwave Drying ◽  
Sustainable Utilization ◽  
Drying Process ◽  
Production Lines ◽  
Sample Weights ◽  
Valuable Metals ◽  
Energy Aspects

Abstract Nickel-containing residue (NCR) is a hazardous solid waste from battery production lines. Recently, the interest in recovering valuable metals from NCR has increased because sustainable utilization of resources is more and more valued. Drying is a key part of the recovery process. In this study, we measured the dielectric properties of the NCR for different moisture contents and temperatures using the cavity perturbation method at 2.45 GHz. The microwave absorption characteristics of NCR had a positive correlation with the moisture content, while it was less efficient in the 20-180°C temperature range. Then found that the microwave drying data at different microwave powers (400-700 W) and for different sample weights (60-120 g) have a better fit with the Midilli-Kucuk model. The activation energy (Ea) was received as 9.76 W/g using an exponential expression based on the Arrhenius equation. Finally, the energy consumption reduce 110 W·h/kg than that of drying with a single microwave power by optimizing the microwave drying process.

Analytic Study on On-Line Model of Moisture in Hot Air Drying Process of Grain

2017 ◽  
Vol 872 ◽  
pp. 360-372
Author(s):  
Zhi Wei Mai ◽  
Bi Ying Wang ◽  
Chang You Li
Keyword(s):  
Moisture Content ◽  
Cross Flow ◽  
Drying Rate ◽  
Drying Process ◽  
Counter Flow ◽  
Drying Characteristics ◽  
Concurrent Flow ◽  
Content Ratio ◽  
Real Time Tracking ◽  
Drying Technology

This study aims to review variation pattern of moisture content ratio of grains in deep-bed drying process, guide the drying technology design, realize real-time tracking and regulation in drying process, improve the quality of drying process and reduce energy consumption. Based on the moisture diffusion model in thin layer drying process, the principle of mass conservation of deep drying process, state function and irreversible thermodynamics analytic method, we have established and solved basic equations of deep-bed drying of grains, obtained the moisture content ratio of grains and analysis formula of drying velocity distribution in processes of concurrent flow drying, counter flow drying, cross-flow drying and standing drying and resolved the sustained decreasing drying process of grains in the concurrent flow drying and extreme point of drying rate in the counter-flow drying. Under the same conditions of temperature, humidity and air output, the drying velocity in counter-flow drying significantly higher than that in the concurrent flow drying. It means the energy utilization effects in counter-flow drying is better than that in the concurrent flow drying. Drying characteristics of grains in cross-flow drying and standing flow drying are the same, while drying rates in inlet-air side and outlet-air side vary widely. It means that when the layer thickness is 0.5m and the moisture content is over 20%, the drying rate in outlet-air side is nearly zero and the drying uniformity is bad. Tests on 5HP-3.5 recirculation drier shows that maximum deviation between analytic value and measured value in deep drying process is 0.69% and the range scope is -0.27%-0.69%. From the drying characteristics of grains, deviations mainly come from instrument detection deviations. The analytic method has important significance for realizing real-time tracking and regulation in drying process, guiding drying technology design, reducing energy consumption, increasing drying rate and drying machine capacity.

Experimental Study on the Xilingol Lignite Dewatering in Microwave Field

2013 ◽  
Vol 868 ◽  
pp. 442-446
Author(s):  
Wei Dong Wang ◽  
Xiao Yang ◽  
Jing Wen ◽  
Meng Hui Lu ◽  
Chen Gao ◽  
...  
Keyword(s):  
Microwave Field ◽  
Size Composition ◽  
Microwave Drying ◽  
Drying Rate ◽  
Drying Characteristics ◽  
Fine Coal ◽  
Mass Losses ◽  
Drying Rates ◽  
Drying Curves ◽  
Superficial Area

Microwave drying characteristics of Xilingol lignite were investigated with microwave drying testing equipment at 2450 MHz. Effects of particle size has been carefully studied. Mass losses of the samples were measured during drying. Drying rates were then obtained through the trends of drying curves. Results show the 0.6-1mm sample has low drying rate. Changing the stacking superficial area and size composition has been tested and resulted that only mixed with fine coal can increase the drying rate of 0.6-1mm. But classification experiment shows sieving 0-6mm sample into fine sample and coarse sample cannot advance the drying rate obviously.

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