EGI Research, Development of Continuous and Large-Scale Waste Plastic Pyrolysis Process

The Korea Institute of Energy Research (hereinafter KIER) announced on the 28th that Dr. Hwang Byung-wook's research team from the CCS Research Group has successfully developed a process that applies a circulating fluidized bed process to enable the recycling of waste plastics and the mass production of pyrolysis oil.

(From left) Daewook Kim, Dr. Byungwook Hwang, Yujin Choi, Jaejun Jang, Student Researcher. Provided by Korea Institute of Energy Research

According to KIER, countries around the world are focusing on recycling technologies such as pyrolysis as eco-friendly methods to handle the increasing amount of waste plastics. Recently, the Korean government also announced plans to expand the annual pyrolysis treatment of plastics from 10,000 tons to 900,000 tons by 2030.

Currently, the kiln method is used for pyrolyzing waste plastics in Korea. The kiln method is a process where waste plastics are placed inside a cylinder, heated externally, and the generated vapor is condensed to obtain pyrolysis oil. Although the process design is simple, as the cylinder size increases, heat transfer from the outside to the center becomes difficult, limiting scalability.

In particular, the kiln method can only process less than 20 tons of plastic per day. This amount is far insufficient to achieve the government's target of 900,000 tons of annual pyrolysis treatment. Additionally, continuous external heat supply is required, and since the process can only restart after residual waste disposal, continuous operation is impossible, which is another drawback.

To overcome the limitations of the existing process, the research team developed a technology that applies a circulating fluidized bed process to recycle waste plastics. The circulating fluidized bed process is a combustion method where heat media such as sand, heated to high temperatures by fuel combustion, circulates continuously to transfer heat. The research team applied this process to waste plastic pyrolysis for the first time in the world, enabling continuous processing and scaling up, which were limitations of the existing process.

The core of the developed process is heat circulation. The catalyst in the form of heated solid particles in the combustion reactor moves to the pyrolysis reactor following the airflow and transfers heat. The heat obtained here is used to pyrolyze the input waste plastics. Then, the cooled catalyst returns to the combustion reactor along with the residues. The residues generated in this process are incinerated, and the catalyst is reheated by the incineration heat and moved back to the pyrolysis reactor to pyrolyze the waste plastics again.

By utilizing this process, continuous circulation from raw material input to heat supply and residue treatment becomes possible, enabling continuous operation. Above all, because the catalyst freely moves inside the reactor, heat can be evenly transferred from the center to the edges of the reactor, allowing for scaling up, the research team explained.

Through experiments, the research team confirmed that the process can pyrolyze not only plastics but also solid recovered fuel (SRF, products made from waste synthetic resins, waste rubber, waste wood, etc., manufactured to be used as fuel in power plants) produced from household waste, processing 100 kg of waste plastics per day.

Dr. Hwang Byung-wook of KIER said, “The greatest significance of this research is that we designed a system capable of continuously pyrolyzing waste including waste plastics and developed the technology to realize it.” He added, “The technology developed by the research team is a core pyrolysis technology capable of processing large amounts of waste plastics and producing high-quality pyrolysis oil, making it highly suitable for achieving Korea’s waste plastic pyrolysis goals.”

This content was produced with the assistance of AI translation services.