Kinetic Studies of Low Severity Visbreaking

Thermal cracking of vacuum residues and asphalts obtained from operating Indian refineries were studied in a batch reactor. The temperature was varied in the range 400−430 °C, and the batch time was varied from 0 to 15 min. The pressure was kept at a constant value of 1.2 MPa through out the experiment. The variation in the composition of the cracked gas fraction for each feed was studied by gas chromatography. The resulting visbroken products were further characterized in terms of its different industrially important boiling cuts. A five lump kinetic model, comprising of gas (C1−C5), gasoline (IBP-150), LGO (150−350), VGO (350−500), and VR (500+) has been developed. The variation in the kinetic parameters with change in the feed properties has been discussed. Also, an attempt has been made to seek a relationship between the feed properties with the kinetic rate parameters and the activation energies.