Data Standardization Using an Extensible Mark-up Language (XML) to Estimate Kinetic Parameters for Refinery Processes. Case Study: Hydrocracking

Data standardization using an eXtensible Mark-up Language (XML) to estimate kinetic parameters for refinery processes. Case study: Hydrocracking

L.C. López ¹, J.J. Arias ¹, M.Kraft²,   A. Molina^*1.

¹ Universidad Nacional de Colombia – Sede Medellín, Facultad de Minas, Bioprocesos y Flujos reactivos, Medellín, Colombia

² University of Cambridge, Department of Chemical Engineering and Biotechnology, Computational Modelling Group, Cambridge, United Kingdom.

^*Corresponding author: amolinao@unal.edu.co

Extensible Mark-up language (XML) was used to standardize kinetic data of refinery processes. In this work this standardization process is illustrated with hydrocracking as case study. Hydrocracking is a refinery process used to convert vacuum gas oils into high-value fuels. With hydrotreatment, it allows processing of heavy crude oils with high sulfur, nitrogen and metals content. To face the challenge of the high demand of lighter products such as naphtha, gasoline, kerosene and light gases, the processing and upgrading of heavy residue has attracted the attention of the refinery industry. Several kinetic mechanisms [1-8] have been reported on the hydrocracking literature. These mechanisms use lumps to represent the large numbers of chemical compounds present in the feed with a smaller number of pseudocomponents.

One interesting characteristic of the literature available on crude oil refining, and particularly on hydrocracking, is that each research proposes an individual set of kinetic parameters. The data obtained by other groups is normally lost or, in the best case, only used for comparison. This research looks for a methodology that helps in the standardization of these data so that more robust mechanisms can be developed. This paper deals particularly with how eXtensible Mark-up Language (XML) can be use as the standardization methodology and is applied to hydrocracking as illustrative case.

To model hydrotreatment, the mechanism proposed by Martínez et al. [8] was selected as it has the right complexity level, universality, availability of experimental data and availability on kinetic parameters to represent the hydrocracking of Colombian heavy oil. The kinetic parameters originally proposed in [8] were regressed to obtain a new set that represents industrial data for a Colombian hydrocracker.   A set of simulations were carried out in the software Matlab with the same temperature profile, reactor dimensions and catalyst of an industrial hydrocracking reactor that was approximated as a Packed Bed Reactor (PBR).

The kinetic parameter estimation started with the construction of an  open-source database, that includes kinetic data and experiments from 10 different sources, written using an eXtensible Mark-up Language (XML). The database includes data previously reported in open literature, and data from the Hysys hydrotreatment black-box model [9] and industrial data. The comparison with multiple sources improves the universality of the model.

Once the database was completed, the fmincon routine available in the Matlab Optimization Toolbox was implemented to minimize the mean square error between the data obtained by the model and the various external source data described above.

A first simulation using only industrial data was done to estimate a set of kinetic parameters.The results show good agreement between the industrial data and the model with an associated relative error less than 5% for all exit flows of the reactor.

References

[1]      D. I. Orochko, I. Y. Perezhigina, S. P. Rogov, M. V Rysakov, G. N. Chernakova, “Applied over-all kinetics of hydrocracking of heavy petroleum distillates,” Chem. Technol. Fuels Oils, vol. 6, no. 8, pp. 561–565, 1970.

[2]       S. Sánchez, M. A. Rodríguez, J. Ancheyta, “Kinetic Model for Moderate Hydrocracking of Heavy Oils,” Ind. Eng. Chem. Res., vol. 44, no. 25, pp. 9409–9413, 2005.

[3]       S. M. Yui, “Mild Hydrocracking of Bitumen-Derived Coker and Hydrocracker Heavy Gas Oils: Kinetics, Product Yields, and Product Propertied,” pp. 1278–1284, 1989.

[4]       M. A. Callejas, M. T. Martínez, “Hydrocracking of a Maya Residue. Kinetics and Product Yield Distributions,” Ind. Eng. Chem. Res., vol. 38, no. 9, pp. 3285–3289, 1999.

[5]       K. Aoyagi, W. C. McCaffrey, M. R. Gray, “Kinetics of Hydrocracking and Hydrotreating of Coker and Oilsands Gas Oils,” Pet. Sci. Technol., vol. 21, no. 5–6, pp. 997–1015, Jan. 2003.

[6]       C. Botchwey, A. K. Dalai, J. Adjaye, “Product Selectivity during Hydrotreating and Mild Hydrocracking of Bitumen-Derived Gas Oil,” Energy & Fuels, vol. 17, no. 5, pp. 1372–1381, Sep. 2003.

[7]       C. Botchwey, A. K. Dalai, J. Adjaye, “Kinetics of Bitumen-Derived Gas Oil Upgrading Using a Commercial NiMo/Al 2 O 3 Catalyst,” vol. 82, no. June, pp. 478–487, 2004.

[8]      J. Martínez, J. Ancheyta. “Kinetic model for hydrocracking of heavy oil in a            CSTR involving short term catalyst deactivation”. Fuel. Vol 100 pp. 193-199, 2012.

[9]      AspenTech, Aspen Hysys (Versión 8.4) [Software].