The waste plastic oil treatment process consists of seven stages 1994.12.15

 (1) Pre-treatment process: After sorting and separating foreign substances (cans, bottles, metals, etc.) mixed in the waste plastic, the waste plastic is crushed to a size that can easily fit into the melting drum (2).

 (2) Melting process: Waste plastic is heated to approximately 200-300°C and either dissolved into liquid itself or melted into liquid by adding a solvent such as kerosene. If the waste plastic contains vinyl chloride (PVC), the PVC decomposes at a temperature of 200-250°C, producing toxic hydrogen chloride gas. If this gas is discharged from the system, most of the hydrogen chloride is removed in the melting process. Recently, the use of this process as a dehydrochlorination process has been attracting attention. The hydrogen chloride gas generated in this process is sent to the neutralization process for treatment. 

 (3) Pyrolysis process: This process is noteworthy because, although the decomposition reaction rate increases as the temperature is raised, it also causes such inconveniences as a decrease in the yield of liquid components and the progression of carbonization. Because of these problems, the key to the process design is the temperature range to be selected. Liquid waste plastic is heated to about 300~500°C for decomposition. In order to obtain as much of the liquid petroleum component as possible at room temperature, a catalyst (zeolite or metal) may be used. Since this catalyst has recently been developed, it can be used to obtain as much of the liquid petroleum component as possible at room temperature. Liquid material, i.e., the product

 The yield and quality of the sleeves have been improved. To reduce the amount of heavy oil (light and heavy ponds) and obtain more light oil (gasoline and kerosene) without the use of a catalyst, it is necessary to perform pyrolysis reactions at higher temperatures for longer periods of time, which can lead to carbonization phenomena and operational traps such as line blockages, increased residues, or even lower yields and quality. This can also lead to a decrease in yield and quality. The use of a catalyst can increase the yield of the pond, especially the yield of light oil, and is also superior in terms of quality.

 (4) Product oil (product) recovery processThe high-temperature pyrolysis gas generated in the pyrolysis process is cooled to room temperature with cooling water to obtain the product in liquid form. The quality, properties, and yield of the product vary greatly depending on various conditions, such as the type of plastic fed, reaction temperature, reaction time, and whether or not a catalyst is used.

 (5) Residual treatment process: Small foreign substances (sand, glass, metal, wood chips, etc.) that could not be separated in the pretreatment process and carbides, etc. generated by thermal decomposition are collected by filtration or removed.

 (6) Neutralization treatment process: Hydrogen chloride gas generated from the thermal decomposition of PVC is neutralized with caustic noda, slaked lime, or other alkali to detoxify or recover the gas.

 (7) Exhaust gas treatment process: This process treats flammable gases (carbon monoxide, methane, propane gas, etc.) generated in the pyrolysis process that are difficult to condense. It may be incinerated directly on a flare stack, etc., or it may be reused in the system by converting it into fuel for pyrolysis or an energy source of electricity or steam.