Aromatic distributions

Figure 4.20 MTG/MTO reaction path and aromatics distribution with different zeolites as catalysts. (Reprinted from C.D. Chang, W.H. Lang, W.K. Bell, Catalysis in Organic Reactions, Molecular Shape-Selective Catalysis in Zeolites, pp. 93-94. Copyright 1981. With permission from Marcel Dekker.)...

Bicyclic aromatics and naphthenes are important components of cracking feed stocks. The former, after cracking in the side chains to gasoline and gas, will remain as smaller bicyclic aromatics in the cracked gas oil. The latter will be converted to naphthenes and aromatics distributed in both the gasoline and gas oil, together with aliphatic gas and gasoline components. 

Besides olefines, zcoliies such as ZSM-5 permit the conversion of methanol into aromatics. The Cs fraction can contain up to 50% aromatics in the Cu range [23]. Depending on the pore diameter of the zeolite applied, different aromatics can be obtained. Table IV exhibits the aromatic distribution derived from various zeolites. 

In the experiment with the sulfided catalyst at 37S C (fig- 2c), catalytic hydrogenation occurs changing the aromatic distribution in the products. However, it is possible to see a... 

Table 6.11 Site-specific deuterium distribution in benmldehyde by source. Adapted from [280] with kind permission, Copyright [1992] American Chemical Society. Values f[i] are the mole fractions of site-deuterated molecular species i. ADR (aromatic distribution ratio) = f ]ortho]/f ]meta + para]. The (D/H) are expressed in total parts per million [ppm] and are determined by standard combustion and IRMS...

Pl(NH3)4Cl2. However, the aromatics distribution in the BTX fraction was shilled towards benzene (48.8 %) and toluene (35.7 %) as compared with Ga/H7.SM-5. 

The zeolite catalysts with and without binder are compared for the distribution of aromatics formed over them at the same propane-to-aromatics conversion (3 and 10%) in Table 5. The comparison indicates that the influence of binder on the aromatics distribution is small. 

FIGURE 8.13 Aromatics Distribution by number of aromatic rings in EOR RDS-VGO product streams from Chevron studies. 

Radke, M., Welte, D. H. WiLLSCH, H. 1982a. Geochemical study on a well in the Western Canada Basin relation of the aromatic distribution pattern to maturity of organic matter. Geochim. Cosmo-chim. Acta, 46, 1-10. 

Fig. 6. Total aromatics content and aromatics distribution obtained in the hydrogenation of a hydrated LCO (HT-LCO) over the different Pt supported catalysts. Reaction temperature 300 C. The values corresponding to the HT-LCO feed are also included for comparison. (0) Mono-aromatics. ( ) Di-aromatics. ( ) Tri. ...

The typical MTG aromatics distribution is shown in detail in Table 2 [1], along with the calculated (normalized) thermodynamic equilibrium values. The xylenes are seen to be essentially at equilibrium, but departure from equilibrium distribution becomes more pronounced with higher aromatics. 

Currently, the feed lump distribution is developed by routine measurement and it is unachievable for any modeling technique to accurately estimate the molecular information of oil fraction (such as PNA content, multi-ring aromatics distribution, hindered and non-hindered sulfur content) by using routine measurement only. Therefore, the resulting model is sensitive to feed stock and needs to be re-calibrated when the feed stock is changed from base case. If detail molecular information of feed stock is available, the feed lump distribution can be customized to better characterize feed stock. 

Also Meindersma Haan presented a conceptual process design for the separation of aliphatic/aromatic hydrocarbons, in which the authors concluded that ILs which show a high aromatic distribution coefficient, Danm = 0.6 m/m, with a reasonable aromatic/ aliphatic selectivity, Samm/aUf = 40, could reduce the investment costs of the aromatic/aliphatic separation to about M 25 to 30 and the annual costs to M 16 to 17 respect to total investment costs in the typically applied sulfolane extraction process (Meindersma de Haan, 2007). 

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