Use of polypropylene pyrolysis oil in alternative fuel production.

In this study, polypropylene (PP) was recycled in a non-stirred batch reactor by slow pyrolysis at low temperature. Virgin PP and waste PP as well as mixed material of equal amounts of virgin PP plus virgin PP pyrolysis oil (ratio 1:1 w/w) were used as raw material. The highest yields of liquid product were obtained at 350°C and 400°C (82.0 and 82.3 w/w%, respectively). The density, viscosity and calorific value of the gasoline and diesel fractions of the obtained pyrolysis oils comply with EN228 and EN590 standards, respectively. The flash point corresponded to the standard only for some of the oils, but the cold filter clogging point, the pour point and especially the oxidation stability were far above the stated reference values of the standards. The pyrolysis oils as products of thermal decomposition were determined by the methods of 1H and 13C and two-dimensional-heteronuclear single quantum coherence nuclear magnetic resonance (2D-HSQC NMR) spectra. Spectral analysis showed that only very little aromatic compounds were present in the oils, but they contained many unsaturated compounds, which is presumably consistent with the measured oxidation stability and limits their use in the production of alternative fuels. The research octane number (RON) calculated from the NMR analyses corresponds to the lower limit of gasoline.

Vertical distribution of polycyclic aromatic hydrocarbons in the brackish sea water column: ex situ experiment.

BACKGROUND: Oil spills can cause severe damage within a marine ecosystem. Following a spill, the soluble fraction of polycyclic aromatic hydrocarbons is rapidly released into the water column. These remain dissolved in seawater over an extended period of time, even should the insoluble fraction be removed. The vertical distribution of the aromatic hydrocarbon component and how these become transferred is poorly understood in brackish waters. This study examines the vertical distribution of polycyclic aromatic hydrocarbons having been released from a controlled film of spilled oil onto the surface of brackish water. METHODS: The study was undertaken under controlled conditions so as to minimize the variability of environmental factors such as temperature and hydrodynamics. The distribution of polycyclic aromatic hydrocarbons was measured in the dissolved and suspended phases throughout the 1 m water column with different intensity of water sampling: 1, 2, 4, 7, 72, 120, 336, 504 and 984 h. RESULTS: The total concentration of polycyclic aromatic hydrocarbons ranged from 19.01 to 214.85 ng L-1 in the dissolved phase and from 5.14 to 63.92 ng L-1 in the suspended phase. These hydrocarbons were released immediately following a controlled spill attaining 214.9 ng L-1 in the dissolved phase and 54.4 ng L-1 in the suspended phase near the cylinder bottom after 1-2 h. The 2-3 ring polycyclic aromatic hydrocarbons dominated in the dissolved phase (60-80%), whereas the greater amount of 4-6 ring polycyclic aromatic hydrocarbons (55-90%) occurred in the suspended phase. A relatively low negative correlation (rS = -0.41) was determined between the concentration of phenanthrene and suspended matter, whereas a high negative correlation (r =  - 0.79) was found between the concentration of pyrene and suspended matter. Despite the differences in the relationships between the concentration ratio and amount of suspended matter the obtained regressions allow roughly to predict the concentration of polycyclic aromatic hydrocarbons.