What is pyrolysis of plastic ?

Pyrolysis of plastic

Pyrolysis is the process of thermally degrading long chain polymer molecules into smaller, less complex molecules through heat. The process requires intense heat with shorter duration and in absence of oxygen, able to produce high amount of liquid oil up to 80 wt% at moderate temperature around 500⁰C. We can get three major products through the pyrolysis of plastic, plastic pyrolysis oil, gas and carbon black, which are valuable for industries especially production and refineries. The plastic pyrolysis oil have high calorific value that could be used as an alternative fuel in multiple applications such as furnaces, boilers, turbines and diesel engines without the needs of upgrading or treatment.

Waste plastic pyrolysis plant to fuel oil

In addition, pyrolysis of plastic is also very flexible since the process parameters can be manipulated to optimize the product yield based on preferences. Parameters play major role in optimizing the product yield and composition in pyrolysis of plastic. There are several parameters that influence liquid oil production in pyrolysis of plastic.

1.In pyrolysis of plastics, temperature is one of the most significant operating parameters since it controls the cracking reaction of the polymer chain. Different plastics have different degradation temperature depending on the chemical structure. For common plastics such as PE, HDPE, LDPE, PP and PS, the thermal degradation temperature started at 350⁰C except for PVC which the degradation started at lower temperature of 220⁰C. However, with the usage of catalyst in the pyrolysis, the optimum temperature could be lowered and higher liquid yield was obtained.

2. Besides temperature, right reactor selection for the pyrolysis of plastic is also crucial to increase efficiency of the reaction towards achieving the final desired product. The plastic pyrolysis reactor we DOING manufacture is strictly according to the standard of pressure vessels(boiler grade). The round-shape reactor head has very strong tension and good connection with the reactor body, thus could not be cracked under high pressure and high temperature.

DOING pyrolysis reactor for plastic pyrolysis plant

3. Furthermore, pressure and residence time also governed the performance of pyrolysis process. Pressure and residence time are both temperature dependence factors that may have potential influence on product distribution of the plastic pyrolysis at lower temperature. Higher pressure increased the product yield and affected the molecular weight distribution for both liquid and gaseous products. DOING pyrolysis plant is equipped with an accurate calculation system to ensure that the plastic is fully cracked in the reactor, and fully converted into oil and gas, thus the oil yield is high.

The sustainability of the plastic pyrolysis process is unquestionable since the amount of plastic wastes available in every country is reaching millions of tons. With the pyrolysis of plastic, the waste management becomes more efficient, less capacity of landfill needed, less pollution and also cost effective. Moreover, with the pyrolysis of plastic to decompose plastic into valuable energy fuel, the dependence on fossil fuel as the non-renewable energy can be reduced and this solves the rise in energy demand.