Visbreaking of a heavy gas oil fraction promoted by phenol formaldehyde sulphonate polymer

Mild thermal cracking (visbreaking) of the gas oil fraction boiling above 350 degreesC was carried out in the presence of 0.5 wt% of a polymeric phenol formaldehyde sulphonate (PFS) used as a promoter. PFS was prepared and its structure was confirmed through analysis. Cracking reactions were performed in an autoclave and the operating variables including reaction temperature and contact time over a wide range were studied. The reaction pressure throughout the whole investigation was 30 kg/cm(2). Enthalpy, entropy and activation energy values were calculated according to the Arrhenius and the absolute rate theories. The experimental data obtained indicate that the addition of PFS as a promoter accelerates the free radical chain reaction. Kinetic parameters for these reactions further confirmed this view.