Hydrocracking product yields from

Figure 2. Effect of sulfur level in product yields from hydrocracking. 371°C (700° F), 7,000 kPa (1000 psig), 2 LHSV, 5 hydrogen-to-hydrocarbon mole ratio. 0.7 wt % Pd — 15 wt % Nir-SMM, sulfided.

Product yields and qualities obtained from HCK of heavy Safaniya VR are compared in Table 12 [142], As can be seen, higher yields on slurry and ebullated beds are associated with poorer product quality, besides the asphaltene concentration in the hydrocracked VR makes almost impossible any further improvement by further processing. 

The pure compound rate constants were measured with 20-28 mesh catalyst particles and reflect intrinsic rates (—i.e., rates free from diffusion effects). Estimated pore diffusion thresholds are shown for 1/8-inch and 1/16-inch catalyst sizes. These curves show the approximate reaction rate constants above which pore diffusion effects may be observed for these two catalyst sizes. These thresholds were calculated using pore diffusion theory for first-order reactions (18). Effective diffusivities were estimated using the Wilke-Chang correlation (19) and applying a tortuosity of 4.0. The pure compound data were obtained by G. E. Langlois and co-workers in our laboratories. Product yields and suggested reaction mechanisms for hydrocracking many of these compounds have been published elsewhere (20-25). 

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... 

The appendix shows yields and product properties from each of the hydrotreaters and hydrocrackers estimated for the studies. 

In the fourth step, the preprocessor generates plant performance data for the FCC, gas oil hydrocracker, motor reformer and BTX reformer. For each of these process units, the preprocessor calls the appropriate process simulator which computes the usage of equipment and utilities, product yields, and product properties for all base and alternate operations specified by the user. For all of the FCC operations, the feed properties are those of the atmospheric plus vacuum gas oil from the base crude mix blended with a specified fraction of deasphalter overhead. 

The liquid product obtained from thermal cracking can be either catalytically cracked/ hydrocracked or co-processed with a refinery feed. Since the catalytic cracking of oil derived from MWP is more or less problematic, any cracking catalyst can be applied to oil derived from pyrolysis of plastics. But the yield and the quality of gasohne obtained from cracking step vary with the type of catalyst and the properties of the pyrolytic oil derivated from waste plastics. 

Simple distillation to separate the diesel from naphtha and other products is normally required. Hydrocracking of heavier lubes and waxes to maximize diesel yield from the F-T process may also occur. 

For the polycyclic aromatic and hydroaromatic compounds tested in this study, the energy yield from electric discharge hydrocracking for production of the lighter hydrocarbons was in the following order ... 

Table 3.22 Yields and product specifications from hydrocracking a Texan vacuum residue using the H-Oil process...

Because of heat effects of the reactions, the calculated reactor temperature profiles from previous steps would show deviations from actual plant data. We tune the global activity factors again to ensure that the deviations of reactor temperature predictions are within tolerance. We repeat the calibration of reactor temperature profiles and mass yields ofhquid products several times until the errors of model predictions are within the acceptable tolerance. These back-and-forth procedures compose the first phase shown in Figure 6.13 which is a generalized guideline of initial calibration for the Aspen HYSYS Petroleum Refining HCR model. This follows because reactor temjjerature profiles and major liquid product yields are always crucial considerations for any hydrocracker. 

The continuous kinetic lumping model, in contrast to the discrete lump model, is able to predict the whole distillation curve of hydrocracked product. For instance. Table 11.2 shows predicted product compositions for two cases, five lumps and nine lumps, obtained with Equation 11.9 with the optimized parameter values. In the case of the continuous kinetic lumping model, it allows for predicting the entire boiling point, and the yield of any fraction can be defined at convenience without any other recalculation of parameters that is why results for five and nine lumps are easily generated, while in the case of the discrete lumping model, only results for five lumps are reported, and to obtain information for nine lumps apart from the new parameter estimation, more experiments are indeed necessary. The comparison between the two models can then be only made for five-lumps results. The difference of the predicted product composition with both models compared with the experimental values is small. 

Once the original VGO was subtracted from the hydrocracked product, the corrected distillation curve was utilized for determining the real composition of the prodnct by interpolation nsing a probability distribntion function as reported elsewhere (Sanchez and Ancheyta, 2007). Liquid product volumetric yields were calculated with flows of each product divided by the flow of the corresponding feed (1) residue + VGO, for the... 

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