Abstract

In a thermal cracking process, the molecular bonds of the liquid are broken to the lighter ones. Recently due to the availability of more heavy oils, the process interest was to yield light and middle distillate products. In this research, thermal cracking of vacuum residue in a commercial soaker-visbreaking plant is studied. The product of the process is characterized to the light gas (C₁, C₂), liquefied petroleum gases (C₃, C₄), gasoline (IBP-180°C), gas oil (180 to 320°C) and fuel (320⁺°C). Then to model the visbreaking process, a six-lump kinetic network with fifteen reactions and thirty kinetic parameters is developed. In this model, visbreaking process is modeled as an equal distributed heater, and the soaker is modeled as a complete stirred tank reactor. After evaluating the rate of reactions by estimated kinetic parameters, it is confirmed that a reduced reaction network with seven reaction paths and fourteen kinetic parameters is reliable enough to simulate the performance of the reactor with the absolute average deviation () of 4.75%.

Key words: Kinetic model, visbreaking, lumped model.