Effect of recycled polyethylene catalyst for Mediterranean pine seed shell biomass pyrolysis on hydrogen and methane production

Abstract

ABSTRACT The present study exhibits the potential of hydrogen and methane gases production from the Mediterranean pine tree seed shell biomass over recycled polyethylene wastes as catalyst. In the study, firstly, the viscosity and density of polyethylene materials and degassing point were determined. The pyrolysis was carried out at a rate of 50 °C/min at 600°C temperature. The obtained gases were analyzed with gas chromatography device. At the last step of the experiments, solid residues were observed under an optical microscope, and their microstructures were also examined. The results showed that Mediterranean pine seed shell biomass and its mixture with low-density polyethylene may produce methane and hydrogen gases. M8 catalyst, which has one of the lowest viscosity values (0.45 gr/10 min.) and highest density values (0.950 gr/cm3) produced the highest methane and hydrogen gas yields. In the pyrolysis experiments, 38.44% CH4, 19.50% CO2 and 42.06% H2 gases were obtained from Mediterranean pine seed shell biomass. Moreover, CO2 emission values of biomass were calculated and compared with DEFRA values. The study demonstrated that, since hydrogen and methane can be obtained through the pyrolysis process, Mediterranean pine tree seed shell can be classified as a new biomass source and has potential to alternative fuel to fossil-based fuels for internal combustion engines.