(3) Selection of cotton drying system
1. Basic principles
(1) Cotton fiber is a natural fiber. When subjected to high temperature and heat, its physical and chemical properties will be affected, such as macromolecules The thermal motion of the chain links increases, and as the temperature increases, the macromolecules crack at the weakest bonds, causing the fiber strength to decrease. The decomposition temperature of cotton fiber is 150℃, so the temperature at the mixing point of hot air and cotton fiber should be strictly controlled below 140℃.
(2) The processing capacity of the dryer must be compatible with the ginning capacity, otherwise it will either cause a waste of energy or the water removal rate will not meet the requirements.
(3) Choose a dryer with lower unit heat consumption and good drying uniformity. The unit heat consumption (that is, the heat energy required to evaporate each kilogram of water) is directly related to the operating cost of cotton drying; after drying, the uniformity of the moisture content of cotton (that is, the difference between the highest moisture content and the lowest moisture content of cotton) will It affects the normal progress of subsequent processing and the quality of lint processing.
2. Precautions
(1) Before driving, make sure that all parts of the cotton drying system are normal;
(2) Before driving, adjust the control temperature of the hot air at the mixing point; (3) Before driving, make sure that the fire protection and over-temperature alarm device of the direct heating heating device is normal; (4) Before driving, install the air filter device of the heat exchanger. The fin heat exchanger should be cleaned regularly; (5) After driving, do not turn off the hot air blower at will. When cotton is not needed temporarily in subsequent processes, it can be controlled by opening the air vent valve or closing the electric air cut-off valve;
(6) The starting sequence of the cotton drying system is:
Air heating system→ Drying conveyor system → dryer → external suction system
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