Hydrocracking relative reactions rates

Figure 3.40 Relative reaction rates for hydrocracking of aromatics...

In view of the complicated reaction kinetics of multicomponent systems, it was not clear whether or not the diffusional effects would also affect the relative rate of conversion of feed molecules in a mixture. To answer this question we studied the hydrocracking of three multicomponent systems. The first was a C5-C8 mixture, a C5 360° C boiling range midcontinent reformate which contained 12.5 wt % n-paraffins including 4.2% n-pentane, 4.3% n-hexane, 2.9% n-heptane, l.l%n-octane, and <1% C9+ n-paraffins, with the remainder isoparaffins and aromatics. The reaction was carried out at 400 psig, 2 H2/HC, 2 LHSV, and 800°F. Secondly, a Cg-Cie mixture... 

Table 6. Relative Rates for Groups of Hydrocracking Reactions (as Shown in Figure 15)...

Figure 15. Hydrocracking reaction chain for poly aromatic and naphtheno-aromatic compounds, per Filimononv, et al. The relative rates of Reactions 1 to 12 are shown in Table 6.

Kinetics is the study of the rates of reaction. The rates of reaction determine the key properties of a hydrocracking catalyst initial activity, selectivity, stability and product quality. The temperature required to obtain the desired product at the start of the run measures the initial activity. In general, the catalyst activity is a measure of the relative rate of feedstock conversion. In hydrocracking, activity is defined as the temperature required obtaining fixed conversion under certain process conditions. Hydrocracking conversion is usually defined in terms of change of endpoint ... 

ABSTRACT. A fundamental approach is outlined for the kinetic modeling of complex processes like thermal cracking or catalytic hydrocracking of mixtures of hydrocarbons. The reaction networks are written in terms of radical mechanisms in the first case and of carbenium ion mechanisms in the second case. Since the elementary steps of the networks pertain to a relatively small number of classes, the number of rate coefficients is kept within tractable limits. The reaction networks are generated by computer through Boolean relation matrices. The number of continuity equations is limited by the elimination of radicals or carbenium ions through the pseudo-steady-state approximation. 

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