High Temperature Steam Gasification of ABS, PE and PC in a Batch Reactor

ABS (Acrylonitrile Butadiene Styrene), PE (Polyethylene) and PC (Polycarbonate) plastic pellets were gasified in a batch furnace experiment and the product tars were captured, cooled and measured. High temperature steam was used as an oxidizing and reforming agent at three different temperatures: 700°C, 800°C and 900°C. The second important parameter was steam to carbon (S/C) ratio, where the value of 1.0 represented the stoichiometric amount of steam and 0.0 stands for pyrolysis. The experiments were performed at values S/C values of 0.0; 1.2; 2.0; 3.6 and 5.0. The reaction distance and nitrogen flow rate were modified in order to achieve product residence time of 25 seconds.

The reactor is a horizontal batch reactor. It consists of a 1m long glass tube, surrounded by ceramic heaters. A custom loading/unloading mechanism allows for inserting the sample at any desired temperature, without contaminating the system with air. The system also utilizes dichloromethane for gas clean up and tar separation.

Gravimetric tar analysis showed that PE had the lowest amount of tar (<1%) at 900°C and S/C of 5.0. ABS achieved 4% of tar at 900°C and S/C ratio of 3.6. For PC the minimum tar production of 2.3% was detected at 900°C and S/C ratio of 2.0. In addition PC was the only plastic to produce char and ash residue.