The basic principle of thermal decomposition technology is to decompose the original resin polymer in the waste plastic products more thoroughly to make it return to a low molar mass state, thereby obtaining products with high use value. The thermal decomposition mechanism and thermal decomposition products of different types of pallet containers are different. The thermal decomposition of PE and PP is mainly in the form of random chain scission. There are almost no corresponding monomers in the thermal decomposition products. Thermal decomposition is accompanied by depolymerization and random chain scission reactions. The thermal decomposition products contain some styrene monomers.
The thermal decomposition of PVC first removes hydrogen chloride, and then breaks the chain at a higher temperature to form hydrocarbon compounds. The thermal decomposition process of waste plastics can be divided into high temperature decomposition and catalytic low temperature decomposition. The former is generally carried out at a high temperature of 600-900 ℃, and the latter is carried out at a lower temperature of less than 450 ℃ or even 300 ℃. The decomposition products of the two different. The reactors used for thermal decomposition of waste plastics are: tower, furnace, trough, tube furnace, fluidized bed, and extruder. This technology is a more thorough recycling technology for waste plastics. The method of pyrolysis and recovery of feedstock oil requires a high-temperature reaction, a large investment in equipment, high recovery costs, and coking during the reaction process, which limits its application.