(514e) Data Standardization Using an Extensible Mark-up Language (XML) to Estimate Kinetic Parameters for Upgrading Cracking Processes

Data
standardization using an eXtensible Mark-up Language
(XML) to estimate kinetic parameters for upgrading cracking processes.

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 two of the most important upgrading
cracking processes: Hydrocracking and Fluid catalytic cracking. These processes
convert vacuum gas oils into high-value fuels. Hydrotreatment
is designed for VGOs from heavy crude oils with high sulfur, nitrogen and metals
content and operates under pressure of H₂. Contrary, FCC processes
crude oils in an atmosphere without hydrogen at lower pressures. 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 for
both processes [1-12] have been reported on the open literature. These
mechanisms use lumps to represent the large number of chemical compounds present
in the feed with a smaller number of pseudocomponents.

One interesting characteristic of the literature
available on crude oil refining 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 kinetic parameters to represent the hydrocracking of
Colombian heavy oil. To model hydrocracking a four-lump mechanism proposed by Gianetto et al. [9] was selected.  The kinetic parameters originally proposed in
[8,9] were regressed to obtain a new set that
represents industrial data for a Colombian refinery.   A set of
simulations were carried out in the software Matlab
with the same temperature profile, reactor dimensions and catalyst of the
industrial reactors that were approximated as a Packed Bed Reactor (PBR) and
Plug Flow reactor PFR.

The kinetic parameter
estimation started with the construction of an  open-source
database, that includes kinetic data and experiments from 10 different sources
for both processes, written using an eXtensible
Mark-up Language (XML). 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.

A bootstrap analysis was applied
to calculate the confidence interval and quantify estimation uncertainty for
the kinetic parameters values. The bootstrap method consists mainly in to
generate random sample of size n using originally the experimental data. The
process is repeated a large number of times in order to ensure as much
combinations as possible from the data. The standard deviation of all of the
bootstrap samples estimate the variability of the sampling distribution of each
parameter, and therefore is a measure of the precision of the parameter. 

Results
with an accuracy less than 10% according to
experimental and a set of literature data were obtained using a 1500 bootstrap
replicates for both cracking processes.

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/Al₂O₃
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] A. Gianetto, H.Farag, A. Blasetti, H. De Lasa  ?Fluid Catalytic Cracking Catalyst for
Reformulated Gasolines. Kinetic Modeling? Ind. Eng. Chem
Res. Vol 33. No. 12. Pp.
3053-3062, 1994.

[10] V. W. Weekman
and D. M. Nace, ?Kinetics of catalytic cracking
selectivity in fixed,moving,
and fluid bed reactors,? AIChE Journal, vol. 16, pp. 397?404, May 1970.

[11] M. Larocca,
S. Ng, and H. De Lasa, ?Fast catalytic cracking of heavy gas oils: modeling coke
deactivation,? Industrial
& Engineering Chemistry Research, vol. 29, pp. 171?180, Feb. 1990.

[12] A. C. Barbosa, G. C. Lopes, L.
M. Rosa, and M. Mori, ?Three Dimensional Simulation of Catalytic Cracking
Reactions in an Industrial Scale Riser Using a 11-lump Kinetic?, vol. 32, pp.
637?642, 2013.