The resource utilization of ABS plastic waste with subcritical and supercritical water treatment

Nowadays, the massive accumulation of plastic wastes has caused serious environmental problems, and supercritical water treatment provides a promising way for the clean and efficient utilization of plastic wastes. In this work, the acrylonitrile-butadiene-styrene (ABS)plastic was selected as the feedstock, and the supercritical water gasification experiments for fuel gas production were firstly conducted from 450 °C to 700 °C, at 23 MPa. The increase of reaction time, temperature and material ratio (water/ABS)can significantly promote the gasification reaction, and the whole reaction process was obviously divided into three stages: the gasification efficiency rapidly increased firstly, maintaining nearly unchanged then, and restarted to grow. The subcritical water hydrolysis for oil products recovery was also investigated from 375 °C to 450 °C at 21 MPa, and results show that most of the monomers were converted into more stable substances at long residence time. The optimal reaction condition for monomer recovery was determined to be 400 °C and 3 min through the experimental results.