Experimental investigation on gasification characteristics of polyethylene terephthalate (PET) microplastics in supercritical water

In this work, the gasification experiment of PET microplastics in supercritical water was carried out in a quartz tube reactor. The effect of operating conditions on gasification was investigated. Inspired by marine microplastics, the artificial seawater was provided to gasification. A detailed gasification model of PET microplastics was established to reveal the gasification path. The results showed that the increase in gasification temperature and time improved gasification efficiency, but the increase in reaction pressure had little effect on the characteristics of the supercritical water so that gasification efficiency did not change significantly. The carbon conversion of 98.00 wt% was obtained at 800 degrees C for 10 min. The metal salts contained in seawater promoted the gasification of plastics, which meant that seawater was an efficient utilization route to the plastic gasification. The gasification model demonstrated that PET plastics were prone to form biphenyl, which was not conducive to PET gasification at low temperatures.