Hydrotreating processes for diesel fuels are becoming increasingly important, owing to environmental regulations limiting sulfur and aromatic compounds, which are becoming more strict. Among investigations into hydrotreating modeling, most of the studies use a homogeneous model to simulate the reactor. However, for a real industrial reactor, that is not always an accurate assumption. Furthermore, reports of efforts to find the best operating conditions are very scarce. In this study, a heterogeneous model of three main reactionshydro-desulfurization, hydro-denitrogenation, and hydro-dearomatizationwas applied to simulate the hydrotreating reactor. The model results show a good agreement with literature experimental data. The effects of important operational parameters such as temperature, pressure, liquid hourly space velocity, and H 2 /oil ratio on various hydrotreating reactions are also evaluated. Finally, a multi-objective optimization based on non-dominated sorting genetic algorithm II is carried out to find the best operating conditions for a diesel fuel hydrotreating reactor.

To estimate the amount of dissolved propene gas in various industrial solvents especially in the early time of polymerization in slurry-phase propene polymerization and consequently achieve real polymer productivity, the precise experimental solubility data are needed. The solubility of propene in methylbenzene and heptane was measured at pressures from (0.13 to 1.27) MPa and temperatures ranging from (313 to 359) K. A static apparatus is used to measure the experimental data. The experimental data are modeled using the Peng−Robinson cubic equation of state (PR CEOS) with the van der Waals (vdW) mixing rule with two adjustable parameters. The modeling results show that the PR CEOS is capable to represent the experimental data well.

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Hydrocracking (HC) is becoming a more important process in refineries owing to increasing demand for gasoline and jet fuel in comparison with diesel and home heating oils. In a commercial hydrocracking unit, tubular fixed bed reactors (TR) are commonly used. Some disadvantages of these reactors are pressure drop across the tube, high manufacturing costs, and low production capacity. These drawbacks can be solved by using a novel radial-flow, spherical packed bed reactor (SR). The aim of this work is to consider a radial-flow spherical packed bed reactor as an alternative for the tubular packed bed reactor in the HC process and compare the packed beds through important parameters such as pressure drop, yield of products, and temperature profile. The calculations showed that the pressure drop in the spherical reactor is negligible in comparison to that of the conventional tubular reactor. It is shown that by using more catalyst in the SR, the yield of more economical products could be well increased, but doing the same is impossible for TR because of the high pressure drop, which damages the catalyst and their structure in the reactor. Furthermore, the simultaneous effect of catalyst and feed flow rate scale-up ratio on yield of products in the spherical reactor was investigated.

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