تعيين مشخصات و پارامترهاي سينتيك خشك كردن ماده انفجاري پيكريت و طراحي يك خشك كن پيوسته

Determination of Drying Kinetics of Picrite and Design of a Continuous Dryer

A continuous parallel-flow conveyor-belt dryer has been designed for drying of Picrite. The inlet wet solid moisture is about 81% and its outlet will be 0.2% and the thickness of the drying material is 2 cm. According to the general procedure of dryer design, first drying kinetics under conditions of thin-layer kinetics test method have been studied. Then modeling and design of conveyor-belt dryer has been carried out. The drying tests have been done at temperatures of 40°C, 60°C, 80°C and 100°C. The above tests were carried out at two different air flow rates. Interrelated curves including original, drying, drying rate, Krischer and temperature curves have been obtained. Data processing of these curves was used to determine other characteristics and parameters of the drying operation such as heat and mass transfer coefficients, moisture content, humidity, humidity of gas-solid interface, mass and heat diffusion coefficients. Also, through the modeling of this work, the dryer has been divided in two hindered and unhindered parts and equations of microscopic and macroscopic heat and mass balance have been derived and solved and subsequently, the final parameters and coefficients of this dryer have been obtained. The experimental device consists of a blower, a desiccator, steam supplier, orifice meters, heater, inlet and outlet psychrometers, drying duct and sampling unit. Accordingly, dynamic control of velocity, temperature and humidity of the flowing gas has been implimented.