Hydrocracker Model

Figure 6. Hydrocracking model of n-lieptaiie witli Pd-liybrid catalyst.

Hydrocracking Modelling with single events methodology Exhaustive description of reaction network needed ... 

This section first discusses the reaction mechanism for paraffin hydrocracking and the thus-derived modeling specifications for each reaction family. This is followed by a discussion of the automated model building algorithm and the QSRC/LFERs used to organize the rate parameters. Finally, the thus-developed Cig paraffin mechanistic hydrocracking model diagnostics are presented. 

The mechanistic paraffin hydrocracking model builder has a database of all reaction matrices and rules for all mechanistic paraffin hydrocracking reactions, involving both metal and acid chemistries, with the flexibility of changing them. A detailed library of parafifins, olefins, and ion intermediates consisting of their connectivity and thermod5mamic information was built... 

A Ci6 hydrocracking model with 465 species and 1503 reactions was built automatically in only 14 CPU seconds on a Pentium Pro 200 PC. The corresponding plug flow reactor (PFR) model with molar expansion was then... 

Figure 5. Parity Plots for Cig Paraffin Hydrocracking Model at Various Operation Conditions (T, P, LHSV, and Inhibition)...

The thus-deduced Cso paraffin hydrocracking model containing 306 species and 4671 reactions was automatically generated on the computer. This model can thus be further tuned to capture the carbon number distribution and iso-to-normal ratio in the paraffin hydrocracking process. 

Graph theoretic concepts were used to construct a paraffin hydrocracking mechanistic model builder incorporating bi-flinctional catalysis with metal and acid functions. The complete automated approach was successfully demonstrated for a Cm paraffin hydrocracking model with 465 species and 1503 reactions at the mechanistic level. 

The generalized isomorphism algorithm was applied at the carbon and branch number level to reduce the complexity and explosion of modeling heavy paraffin hydrocracking. A thus-deduced Cso paraffin hydrocracking model with 306 species and 4671 reactions at the pathways level was developed from the teachings of the Cie model. 

AHYC is an update of SARCRACK, a hydrocracker model developed by Sun Oil Company/ and modified by Suncor Sarnia with assistance from DMC corporation for online optimization. The component slate and reaction network for AHYC are consistent with publications by Klein, et al., Stangeland, Quann, et a M Filiminov, et al., and Jacobs. ... 

Again, we ran the case study using the hydrotreating portion of the Suncor-Samia hydrocracker model with an equal-outlet temperature profile. For 500 wppm sulfur in the product, the makeup H2 flow is 15.2 MMSCFD. For 15 wppm, the makeup flow is 18.6 MMSCFD, more than 40% higher. Higher WART leads to increased conversion, increased HDN, and (up to point) increased saturation of aromatics. This explains why the hydrogen consumption increased so much— and so non-linearly— when the target product sulfur content went from 500 wppm to 15 wppm. 

The cahbration process for the FCC is square . This implies that there are no user adjustable tuning factors unlike the Aspen HYSYS Reformer or Hydrocracking models. In other words, the number of tuning parameters equals the number of available measurements and the calibration is a much simpler root-finding exercise. In general, the calibration process is quick and converges within 20 iterations. If there is difficulty during calibration, it is mostly likely due to inconsistent product measurements. 

Basak, K., Sau, M., Maima, U., Verma, R.P. 2004. Industrial hydrocracker model based on novel continuum lumping approach for optimization in petroleum refinery. Catal. Today 98 253-264. 

Other complementary equations of the hydrocracking model are as follows ... 

Experimental data of the sulfur curves, that is, boiling temperature versus sulfur content, was used together with Equation 11.71 and the hydrocracking model parameters previously determined to calculate the model parameters for the HDS reaction. The values of the three parameters are = 7.5h, = 0.08h", and P = 2. 

---