Hydrocracker Products

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],... 

Coonradt and coworkers (13) use an empirical hydrogenation activity index based on the aromatle-naphthene ratio In the hydrocracked product. This approach does not provide an Independent measure of catalytic properties. However, It has the advantage that activities are measured under actual hydrocracking conditions and changes in catalytic properties with catalytic aging can be observed. 

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... 

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 ... 

The cyclic mechanism was demonstrated by comparing the initial product distributions in the hydrogenolysis of methylcyclopentane and in isomerization of methylpentanes and -hexane. For instance, the ratios 3-methyl-pentane/n-hexane, extrapolated to zero conversion, are the same in hydrogenolysis of methylcyclopentane and in isomerization of 2-methylpentane. Since cyclic type isomerization involves first carbon-carbon bond formation and then carbon-carbon bond rupture, one does not expect hydrocracking of alkanes to occur by this mechanism. In contrast, as suggested early on (55), if bond shift isomerization involves first carbon-carbon bond rupture and then carbon-carbon bond recombination, a common intermediate should exist, leading to both the isomerization and the hydrocracking products. 

Distributions of Hydrocracking Products frortt 2-Methylpentane on 10" Metal/AliOi Catalysts... 

Distributions of Hydrocracking Products from 3-Mel/tylpentane on IO", Meta /Al2Oy Catalysts... 

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). 

One of Sun s objectives for the new plant was that the base stocks be at least of the same quality as those from solvent refining, therefore this hurdle had to be overcome. Their solution was to give the total dewaxed hydrocrackate product a light furfural extraction (about 97% raffinate) to remove the tri+ aromatics which appeared to be at the root of the problem.1516 Thus their process involved two solvent extraction steps, one before the hydrocracker and one afterwards. This route gave stable base stocks, but with some residual color. An example of the improvement obtained can be seen in Table 7.10, where 100, 200, and 500 SUS base stocks ( 1, 2, and 3 in Table 7.10) of approximately 110 VI from hydrocracking a distillate/DAO blend were tested for stability before and after furfural extraction. The results show that the extraction improves color relative to unextracted samples for the immediate hydrocracker products and that their performance in the stability test was improved as well by extraction. 

These structural features of the hydrocracked products appear to be reasonably consistent through the boiling range as well (Table 7.18) from analyses on 20 vol. % fractions obtained by distillation ... 

Properties of the base stocks (Table 7.22) compared with solvent extracted stocks show that the hydrocracked products have better colors, Vis, and flash points. Sulfur and nitrogen levels will be in the low parts per million range. 

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