INFLUENCE OF GAS-PHASE REACTIONS ON THE PRODUCT YIELDS OBTAINED IN THE PYROLYSIS OF POLYETHYLENE

The characterization of the product fractions obtained from the pyroly sis of polyethylene (PE) in a laboratory-scale fixed bed reactor was p erformed. The experimental system allowed quantitative information to be obtained on the global tar, char, and gas yields. Pyrolysis runs we re performed using reactor temperatures ranging between 500 and 800 de grees C. The influence of, the residence times in the reactor of the p rimary volatiles generated by the pyrolysis process was also discussed . The secondary reactivity of the tar originated from PE pyrolysis was examined. A lumped-parameters approach was used in order to evaluate the global kinetic parameters for the gas-phase tar-cracking process. PE tars resulted to be more refractory to thermal decomposition than t hose obtained in the pyrolysis of biomass and lignocellulosic material s, but more reactive than tars obtained in the pyrolysis of coal.