Kinetic modeling of dual-stage oxidative extractive denitrogenation of model fuel

Abstract

The petroleum fraction of crude oil is laden with notorious nitrogen compounds, whose removal facilitates fuel oil transport and enhances the longevity of hydrodesulfurization catalysts. Petroleum refining operation thus demands the adoption of unconventional techniques, such as coupled oxidative–extractive denitrogenation. Kinetic models can provide insights into the reaction mechanism and the design and performance of reactors. In this work, nine different kinetic models were developed by applying the Langmuir–Hinshelwood and Eley–Rideal approaches to various reaction pathways. The screening of the kinetic models was done based on the values of the rate law parameters and corresponding R² and adjusted R² values calculated through a multi-parametric, non-linear regression based on the Levenberg–Marquardt algorithm. Out of all the models, the Eley–Rideal model corresponding to the rate expression rs₉ was found to be the best fit, reflecting that hydrogen peroxide remained in bulk while pyridine alone was adsorbed on the catalyst. The selection of suitable extractants for the extractive removal of oxidation products was made based on their extraction efficiency and partition coefficients. The ternary liquid–liquid equilibrium (LLE) data for the (acidulated water-pyridine-isooctane) and (acidulated water-pyridine N-oxide-isooctane) systems were plotted, and Othmer–Tobias, Hand, and Bachman correlations explained the consistency of the experimental LLE data.

Keywords:

• Eley–Rideal model
• kinetic modeling
• Langmuir–Hinshelwood model
• oxidation
• ternary diagram

Acknowledgments

The authors acknowledge the Department of Chemical Engineering, Indian Institute of Technology Kharagpur, India.

Disclosure statement

The authors have no conflicts to declare.

Data availability

Data will be made available on request.

Additional information

Funding

This work was supported by Science and Engineering Research Board, Department of Science and Technology, Government of India.