HYDROCRACKING PRODUCTS DISTRIBUTION

I. M. Keen (British Petroleum Co., Ltd., Middlesex, England) First, how did you impregnate the palladium hydrogenation component onto your catalysts—i.e., what salt did you use Secondly, did you notice any differences in the hydrocracked product distribution from Cr-Ce naphtha using your different ion-exchanged forms of the erionite catalyst ... 

M. Steijns and G. Froment, Hydroisomerization and hydrocracking product distributions from n-decane and n-dodecane, Ind. Chem. Prod. Res. Dev., 20, 654-660 (1981). 

The observation of anomalous cracked product distributions is not limited to zeolites with large cages and small (8-MR) windows. Depending on the feed, it has been observed in 10-MR and 12-MR zeolites as well. Examples of hydrocracked product distributions from decane, dodecane, tridecane and tetradecane on zeolites of the types ZSM-5, BETA and Y are shown in Figs.8 and 9. 

Figure 11. Hydrocracked product distribution from heptadecane on Pt/CSZ-1 zeolite.

Pore size optimization is one area where developmental efforts have been focused. Unimodal pore (NiMo) catalysts were found highly active for asphaltene conversion from resids but a large formation of coke-like sediments. Meanwhile, a macroporous catalyst showed lower activity but almost no sediments. The decrease of pore size increases the molecular weight of the asphaltenes in the hydrocracked product. An effective catalyst for VR is that for which average pores size and pore size distribution, and active phase distribution have been optimized. Therefore, the pore size distribution must be wide and contain predominantly meso-pores, but along with some micro- and macro-pores. However, the asphaltene conversion phase has to be localized in the larger pores to avoid sediment formation [134],... 

Hydrocracking, 30 48-52 behavior, thermal, 29 269 catalytic, 26 383 deethylation, 30 50 demethylation, 30 50 metallocarbene formation, 30 51-52 of f -decane, 35 332-333 primary coal liquids, 40 57 procedure, 40 66-67 product distribution, 30 49 reactions, over perovskites, 36 311 suppression by sulfur, 31 229 zeolite-supported catalysts, 39 181-188... 

Figure 16.7 Influence of support type on product distribution in hydrocracking hydrotreated light Arabian gasoil feed hydrocracked over amorphous and high zeolite catalysts differential yields measured in 50°F (10°C) increments.

It is significant that the mixture yielded propane as the major product (Table III). As noted in our earlier paper on catalytic cracking (6), the predominance of C3 fragments in the cracked products and the absence of isobutane appeared to be a unique property of erionite. Our present data indicate that this is also true for hydrocracking over a dual function erionite. The only exception was that when n-pentane alone was hydro-cracked, equimolal quantities of ethane and propane were found. This shift in product distribution in the presence of n-hexane, a second crackable component, indicated that the reaction path within the intracrystalline space was complicated. 

Besides influencing over-all reaction rates, pore diffusion can cause changes in selectivity. An extreme example of this was observed (26) when a high molecular weight California solvent-deasphalted oil was hydrocracked over a small pore size palladium zeolite catalyst at high temperatures. The feedstock gravity was 16.4° API, and 70% boiled above 966°F. The resulting product distribution is compared with that... 

This picture explains the great differences in product distributions of ideal hydrocracking and catalytic cracking. Furthermore, it is in agreement with the observation that carbon number distributions are similar in ideal hydrocracking of n-alkanes and in catalytic cracking of n-alkenes with the same carbon number (19). 

Schutz and Weitkamp (15) show product distributions for the hydrocracking of dodecane on several noble metals on zeolite catalysts. Product distributions are in general similar to those distributions previously reported for noble metals on ambrphous supports. These results show no major unexpected effect of the zeolitic support differences among the catalysts tested are related to changes in hydrogenation ability or acidity. 

In this paper we compare behavior of catalysts in extinction recycle hydrocracking. In such a processing scheme, all of the feed is ultimately converted to product boiling below a certain predefined temperature. The reaction paths of individual feed components may differ from catalyst to catalyst. Product distributions and properties are examined to determine the general effects of changes in catalytic properties. 

Figure 6. Product distribution in hydrocracking for maximum isobutane yields. 7,000 kPa (1,000 psig), 5 hydrogen-to-hydrocarbon mole ratio, 200 ppm sulfur in feed. 0.7 wt % Pd — 15 wt % Nir-SMM, sulfided.

Product distribution data (Table V) obtained in the hydrocracking of coal, coal oil, anthracene and phenanthrene over a physically mixed NIS-H-zeolon catalyst indicated similarities and differences between the products of coal and coal oil on the one hand and anthracene and phenanthrene on the other hand. There were differences in the conversions which varied in the order coal> anthracene>phenanthrene coal oil. The yield of alkylbenzenes also varied in the order anthracene >phenanthrene>coal oil >coal under the conditions used. The alkylbenzenes and C -C hydrocarbon products from anthracene were similar to the products of phenanthrene. The most predominant component of alkylbenzenes was toluene and xylenes were produced in very small quantities. Methane was the most and butanes the least predominant components of the gaseous product. The products of coal and coal oil were also found to be similar. The most predominant components of alkylbenzenes and gaseous product were benzene and propane respectively. The data also indicated distinct differences between products of coal origin and pure aromatic hydrocarbons. The alkyl-benzene products of coal and coal oil contained more benzene and xylenes and less toluene, ethylbenzene and higher benzenes when compared to the products from anthracene and phenanthrene. The gaseous products of coal and coal oil contained more propane and butanes and less methane and ethane when compared to the products of anthracene and phenanthrene. The differences in the hydrocracked products were obviously due to the differences in the nature of reactants. Coal and coal oil contain hydroaromatic, naphthenic, heterocyclic and aliphatic structures, in addition to polynuclear aromatic structures. Hydrocracking under severe conditions yielded more BTX as shown in Table VI. The yields of BTX obtained from coal, coal oil, anthracene and phenanthrene were respectively 18.5, 25.5, 36.0, and 32.5 percent. Benzene was the most... 

An example of how feedstock composition can influence the variation in product distribution and quality comes from application of the ABC (asphaltene bottoms cracking) hydrocracking process to different feedstocks (Tables 6-18, 6-19, 6-20, and 6-21) (Takeuchi et al., 1986 Komatsu et al., 1986). A further example of variations in product distributions from different feedstocks comes from the Mild Resid Hydrocracking (MRH) process (Table 6-22 Figures 6-14 and 6-15) (Sadhukhan et al., 1986). In addition, different processes will produce variations in the product slate from any one particular feedstock (Figure 6-14) and the feedstock recycle option adds another dimension to variations in product slate (Tables 6-23 and 6-24) (Munoz et al., 1986). 

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