Middle Hydrocarbon Research Articles

Effect of the chemical composition of six hydrotreated light cycle oils for benzene, toluene, ethylbenzene, and xylene production by a hydrocracking process

The effect of the chemical composition of the hydrotreated light cycle oil (HDT LCO) on the benzene, toluene, ethylbenzene, and xylene (BTEX) production by a hydrocracking (HCK) procedure, is presented. Six different types of HDT LCOs were obtained by submitting two types of LCOs to hydrotreating (HDT) with different catalysts and experimental conditions. The products were analyzed as mono-, di- and tri-aromatic compounds using the supercritical fluid chromatography (SFC) method (ASTM D5186). The HDT LCOs were subjected to HCK with a 50/50 in weight mixture of nickel-molybdenum on alumina (NiMo/Al2O3) and H-ZSM5 (NiMo/H-ZSM5, 50/50) at 375 °C, 7.5 MPa, 1.2 h−1, and 750 m3/m3 H2/Oil. The HCK products were analyzed by gas chromatography with a flame ionization detector (GC-FID) and divided into five groups: gas, light hydrocarbons (LHCs), BTEX, middle hydrocarbons (MHCs), and heavy hydrocarbons (HHCs).The results showed that the BTEX formation ranged from 27.0 to 29.8 wt.% and it did not show a significant dependence on the mono-aromatic (59.9 and 75.6 wt.%), total aromatic (61.1–84.2 wt.%) contents or MHCs conversion (58.3–64.3 wt.%) from the departing HDT LCO feedstock. This result implies that, contrary to previous expectations, the BTEX formation does not directly depend on the amounts of total or mono-aromatic compounds when departing from real feedstocks. A GC-PIONA (paraffin, isoparaffin, olefin, naphthene, aromatic) characterization method (ASTM D6623) for mechanism understanding purpose was also carried out.

Effect of the experimental conditions on BTX formation from hydrotreated light cycle oil

The study of a light cycle oil (LCO) upgrading alternative involving hydrotreating and hydrocracking/transalkylation procedures for obtaining a benzene, toluene and xylene (BTX) enriched fraction is presented. The research work was focused on the effect of the experimental conditions on the hydrocracking of an hydrotreated light cycle oil (HDT LCO) in order to produce the highest amounts of BTX, when the catalysts consisted of a mixture (50/50 in weight) of nickel–molybdenum on alumina (NiMo/Al2O3) and ZSM-5 materials (NiMo/ZSM-5 (50)). It was found that 7.4 MPa, up to 375 °C, LHSV of 1.2 h−1 and a H2/Oil value of 442 m3/m3 were the optimal experimental conditions for producing an enriched BTX fraction (31%). In order to facilitate the analysis, the study was carried out considering four types of hydrocarbons as lumps for the feed and HCK products: light hydrocarbons (LHC) composed by C4–C7 non-aromatic compounds, BTX, middle hydrocarbons (MHC) consisting of C7–C10 paraffins and isoparaffins, alkylbenzenes, tetralin and naphthalene derivatives and a small amount of high molecular weight hydrocarbons (HHC). Based on this description, HDT LCO used as feedstock for the hydrocracking (HCK) procedure, presents a 99% of a MHC fraction. The HCK conversion, BTX selectivity and yields were obtained from the chromatographic analysis of the products. A simple kinetic model considering only the MHC conversion was carried out. The obtained activation energy confirmed the endothermic nature of the HCK process. The activity decay of the catalytic mixture was also studied by varying the time on stream.

Hydro‐conversion of oleic acid in bio‐oil to liquid hydrocarbons: an experimental and modeling investigation

AbstractBACKGROUNDThis study focused on understanding the reaction kinetics for the hydrocracking process. Oleic acid, as the main component of most bio‐oils, was selected as feedstock for the hydrocracking process. The hydrocracking of oleic acid was performed in a laboratory scale trickle‐bed reactor in the presence of a Ni–Zeolite β catalyst and hydrogen for hydrogenation. The concentrations of oleic acid and the three main components of jet fuel range hydrocarbons produced, which are nonane, decane and dodecane (C9, C10 and C12), were measured with GC analysis.RESULTSAccording to the aforementioned component concentrations, the rate of reaction and the related Arrhenius equation parameters were estimated. The reaction kinetic calculations were subjected to hydrocracking reactor modeling to gain a better understanding of hydrocracking. The concentrations of C9, C10 and C12 were assumed to be a separate lump of the hydrocarbons produced, namely middle hydrocarbon (MC). The reactant and MC lump concentrations throughout the reactor were measured and compared with experimental data. The modeling and experimental results are in reasonable agreement in terms of MC lump production and oleic acid conversion. The oleic acid and MC concentration profiles and reactor wall temperature profiles along the reactor were examined in this research.CONCLUSIONThe outcome of this study can be applied in simulation and commercialisation of hydrocracking as a potential process for biofuel production. © 2014 Society of Chemical Industry