6-Lump kinetic model for an industrial visbreaking unit

Author(s): S.Reza. Seif Mohaddecy, Sepehr Sadighi

Visbreaking process in refineries refers to the process of reducing the viscosity of a liquid through high temperatures. This is a type of thermal cracking that works by breaking the molecular bonds of the liquid. In this present work, visbreaking of vacuum residue in a commercial soakervisbreaking plant is studied. The product of the visbreaking furnace is characterized to the light gas (C1,C2), LPG(C3,C4), gasoline (IBP-180oC), gas oil (180-320oC) and fuel (320+oC).Afterwards tomodel the visbreaking process, a six-lump kinetic network with fifteen reactions and thirty kinetic parameters is developed. In thismodel, visbreaking furnace ismodeled as a equal distributed heater whilst 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 appropriate to simulate the performance of the reactor with the same accuracy as complete network, which results the final AAD%of the model to 4.75%.

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