Pyrolysis refining is a technology that converts plastic waste into usable energy (such as gasoline, diesel, etc.). This process is usually carried out in an oxygen-free or low-oxygen environment, and the macromolecules are broken down into smaller hydrocarbons by pyrolysis of plastics at high temperatures. Pyrolysis technology is suitable for many types of plastics, the most common of which include:
Polyethylene (PE): includes high-density polyethylene (HDPE) and low-density polyethylene (LDPE). These plastics are one of the ideal feedstocks for pyrolysis refining because they can be converted into high-quality liquid fuels. The pyrolysis products of PE mainly include paraffin, diesel and gasoline, etc.
Polypropylene (PP): Similar to PE, PP can also produce a large amount of liquid fuel during pyrolysis. Since the structure of PP is similar to that of PE, its pyrolysis products are also similar, containing a series of light and heavy hydrocarbons.
Polystyrene (PS) :p S is easily broken down into smaller molecules during the pyrolysis process, so it can be effectively converted into high-quality fuel oil and chemical feedstocks. Pyrolysis of PS can obtain a higher proportion of aromatic compounds such as benzene, toluene, and xylene.
ABS: Due to the presence of acrylonitrile, butadiene and styrene in its structure, ABS can be easily cleaved into smaller hydrocarbon molecules during pyrolysis. ABS is considered to have some potential in pyrolysis refining, especially in the production of liquid fuels and chemical feedstocks.
Nevertheless, it is important to note that not all plastics are suitable for pyrolysis refining. For example, chlorine-containing plastics such as polyvinyl chloride (PVC) can release toxic *** gases during the pyrolysis process, causing damage to equipment and the environment. In addition, multi-layer composite plastics, plastics containing additives or contaminants may affect pyrolysis efficiency and product quality.
Pyrolysis of PET is relatively difficult, mainly because its molecular structure contains strong aromatic bonds and ester bonds, which makes PET have high thermal stability and need to be pyrolyzed at higher temperatures. In addition, the products of PET pyrolysis are complex and may include non-hydrocarbon compounds. PET pyrolysis mainly produces monomer compositions such as terephthalic acid and ethylene glycol, rather than directly generating hydrocarbons that can be used as fuel. Therefore, although PET can be processed by the pyrolysis process, it is considered more of a feedstock for chemical regeneration than for direct refining of fuel.
All things considered, pyrolysis refining technology provides a way to convert plastic waste into valuable resources, but its application needs to be adjusted and optimized according to the type of plastic, pyrolysis system design, and product treatment capacity.