Influence of processing conditions of atmospheric freeze-drying/low-temperature drying on the drying kinetics of sliced fruits and their vitamin C retention

The article discusses a two-stage drying method, including high-temperature and low-temperature drying, is widely used in the USA, France, Italy, especially for corn grain. In this case, the cooling zone in high-temperature dryers is transferred to a drying room, and cooling is carried out in special coolers: in active ventilation bins, platforms or in warehouses. To increase the efficiency of this method, the calculation of the supply of heated grain, the number of mobile fans was performed, and the duration of cooling and moisture removal were experimentally determined.

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Analysis of the process of energy plants drying during the production of solid biofuels

Energy and automation ◽

10.31548/energiya2020.05.110 ◽

2020 ◽

pp. 110-125

Author(s):

R. Shapar ◽

◽

O. Husarova ◽

Keyword(s):

Low Temperature ◽

Total Duration ◽

Raw Material ◽

Residual Moisture ◽

Drying Time ◽

Solid Biofuels ◽

Low Temperature Drying ◽

The Impact ◽

Kinetics Of ◽

Energy Plants

The article presents an analysis of the stages of production of solid biofuels from energy plants and notes that the drying processes in technological processes consume up to 70 % of total energy consumption. The relevance and advantages of low-temperature drying are substantiated. Aim: intensification of the process of dehydration of energy plants, determination of rational parameters of the drying agent and dehydration conditions. Energy willow was used as an object of dehydration. Drying was carried out until the material reached a residual moisture content of 5...6 %. Studies on the effect of drying agent temperature on the kinetics of moisture exchange have shown that increasing the temperature from 80 °C to 100 °C enhances heat and mass transfer and reduces the process duration to 25 %. Increasing the specific load has a positive effect on the productivity of the drying plant and increases the amount of processed raw materials. The total duration of dehydration from the minimum load to the maximum increases by 3.5 times. The paper notes that a significant parameter of the impact on the kinetics of drying and increase the efficiency of the process is the method of grinding raw material. The most intensive mode corresponds to the method of grinding willow by combining abrasion and impact. With this method of grinding, the drying time is reduced from 15 % to 25 % compared to those considered. The established conditions and parameters of low-temperature drying provide intensification and efficiency of the process and obtaining dried energy willow with low and evenly distributed residual moisture.

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REGULARITIES OF CONVECTIVE LOW TEMPERATURE DRYING OF ENERGY SPECIES WOOD

Thermophysics and Thermal Power Engineering ◽

10.31472/ttpe.4.2020.5 ◽

2020 ◽

Vol 42 (4) ◽

pp. 41-49

Author(s):

R.O. Shapar ◽

O.V. Husarova ◽

D.M. Korinchuk

Keyword(s):

Low Temperature ◽

Moisture Content ◽

Raw Material ◽

Biofuel Production ◽

Specific Load ◽

Residual Moisture ◽

Energy Wood ◽

Solid Biofuel ◽

Low Temperature Drying ◽

Kinetics Of

The article presents an analysis of the technological stages of the production of solid biofuel from energy wood species, it is noted that up to 70% of the total energy consumption is spent on drying processes in technological processes. The urgency and advantages of low-temperature drying of such wood have been substantiated. It is noted in the work that the heat and humidity modes should ensure an increase in the energy efficiency of the process and a high calorific value of the resulting fuel. The purpose of the article is to intensify the process of dehydration of energy wood to obtain solid biofuel, to determine the effect on the process of convective low-temperature drying of the operating parameters of the drying agent, the size and shape of the raw material, and the specific load on the drying surface. Energy willow was used as an object for dehydration, the initial moisture content of which varied over a wide range from 45 to 60% per wet weight; dehydration was carried out until the material reached residual moisture content of 5...6%. Studies on the effect of the temperature of the drying agent on the kinetics of moisture exchange prove that an increase in temperature from 80 to 100 °C intensifies heat and mass transfer and reduces the duration of the process by up to 25%. The results of experimental studies of the effect of the specific load on the dehydration process showed that an increase in load has a positive effect on the productivity of the drying unit and increases the volume of processed raw materials. At the same time, the total duration of dehydration from the minimum load to the maximum increases by 3.5 times. It is noted in the work that a significant parameter of influence on the kinetics of drying and increasing the efficiency of the process is the method of grinding the raw material. The most intensive mode corresponds to the method of grinding willow by combining abrasion and impact. With this method of grinding, the drying time is reduced from 15 to 25% in comparison with the others considered. The combination of the specified conditions and parameters of low-temperature drying provides an economical process and obtaining dried willow with low and evenly distributed residual moisture. The use of such material in the technological cycle of biofuel production guarantees the reliable operation of the combustion device for a long time.

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