Open AccessREGULARITIES OF CONVECTIVE LOW TEMPERATURE DRYING OF ENERGY SPECIES WOOD
Author(s) -
Raisa Shapar,
Olena Husarova,
D.M. Korinchuk
Publication year - 2020
Publication title -
teplofìzika ta teploenergetika
Language(s) - English
Resource type - Journals
eISSN - 2663-7235
pISSN - 2663-7243
DOI - 10.31472/ttpe.4.2020.5
Subject(s) - dehydration , water content , humidity , raw material , moisture , pulp and paper industry , convection , materials science , mass transfer , relative humidity , environmental science , chemistry , composite material , thermodynamics , chromatography , biochemistry , physics , geotechnical engineering , organic chemistry , engineering
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.