Vacuum desiccant dryer for PET chip
Vacuum dehumidification dryer is a kind of dryer which can reduce the waste rate and change the adverse effects caused by the uncertainty of drying.
vacuum desiccant dryer principle:
Vacuum degree is the main parameter to control the rapid evaporation of water in raw materials to achieve rapid drying; the vacuum dryer and dehumidification dryer are put together for testing, because the principle of vacuum drying is to use the principle of lowering the evaporation point of low water at low pressure. The results show that the vacuum dryer can save 70% - 80% energy consumption. This is mainly because the desiccant of dehumidification dryer needs to consume a lot of energy in the regeneration process. The drying time of vacuum drying is usually 1 / 5 – 1 / 6 of that of other dehumidification drying. Long time high temperature drying will cause thermal chemical and physical reactions of raw materials, which will reduce the quality of materials, such as color fading and melt index, thus affecting the quality of waste products.
Thus, the possibility of material quality decline is reduced. Taking PC drying as an example, vacuum dryer shortens the drying time of materials. When drying at 120 ℃ and reaching 0.02% final moisture content, dehumidification drying usually takes about 4 hours, while vacuum drying only takes 20-25 minutes. In this way, the drying time of 3 hours and 35 minutes is saved, especially in the application of vacuum dryer in the test section! The drying efficiency is of special importance to precision injection molding manufacturers. Some resins or polymers are highly sensitive. If the drying time is too long, stress may occur, which may lead to scorching, embrittlement and discoloration of parts.
Pet is sensitive to humidity. When pet is melted by heating, excessive humidity can easily lead to hydrolysis and thermal hydrolysis, which reduces the polymerization of the polymer, reduces the molecular weight and leads to poor physical properties. Therefore, good drying is essential.
The belt continuous vacuum dryer is suitable for drying gelatinous substances such as liquid, mud and paste; continuous vacuum dryer is specially sold and designed for small companies.
On the basis of vacuum drying technology, the dryer is constructed by welding various items. The moisture content of PET chip is expected to be reduced to 0.02% (200ppm). Two types of PET are used, new and recycled. Manufacturers and European cereal PET bottles are reprocessed into recycled PET chips, which have similar IV values and molecular weights to the new ones. The moisture content is expected to be less than 0.02% (200ppm), and factors such as temperature, pressure and material are also studied.