Continuous Lumping Model of an Industrial Refinery Isomax Reactor

Sadeghi, M. T.; Shahhosseini, Sh.; Behroozshad, F.

Continuous Lumping Model of an Industrial Refinery Isomax Reactor

Document Type : Full article

Authors

M. T. Sadeghi

Sh. Shahhosseini

F. Behroozshad

Process Simulation and Control Research Lab., School of Chemical Engineering Iran University of Science and Technology (IUST), Tehran, Iran

Abstract

Hydrocracking is an important secondary process in the petroleum industry, generally used to process heavy oil cuts. The process is tailored to various needs of refineries in order to maximize middle distillates, gasoline, LPG and similar products. Therefore, kinetic modeling of hydrocracking reactors applied to upgrade vacuum heavy oil (Isomax) is important and needs to be investigated. In this work, following a brief comparison of continuous lumping model in contrast to discrete lumping model, the former was chosen to model an operational Isomax reactor in Tabriz refinery, located in the North West of Iran. In order to categorise various unknown components True Boiling Point (TBP) of the mixtures were employed as the key parameter. Hence, the hydrocracking rate constant was assumed to be an even function of true boiling point. This would facilitate reformulation of mass-balance equations in terms of rate constant as a continuous variable. In order to determine the fraction yield distribution of the species, a specific distribution function was formulated. The resulting model equations were solved numerically and the yield of various fractions as a function of reactor residence time were estimated. A comparison between model predictions and experimental data shows it can predict the weight percent of light and heavy fractions well with an acceptable accuracy.

Keywords

Hydrocracking

Continuous Lumping Model

Isomax Reactor