Selective hydrogenation of light cycle oil for BTX and gasoline production purposes

Abstract

The study of the best experimental conditions and catalyst for the hydrogenation (HYD) of light cycle oil (LCO) for upgrading purposes was carried out. The objective was to examine the ability of two commercial hydrotreatment (HDT) catalysts for selective aromatic saturation. The effect of the hydrotreatment operation parameters (temperature, pressure, liquid hourly space velocity, H2/HC ratio) on the sulfur and nitrogen contents and in the saturation of aromatic hydrocarbons was also investigated. The goal was to obtain the highest conversion to mono-aromatic hydrocarbons from this di-aromatic (naphthalene derivatives) type feedstock, and at the same time to get reasonable hydrodesulfurization (HDS) and hydrodenitrogenation (HDN) performance to avoid contaminant hydrocarbons for the next step (usually hydrocracking, HCK). An appropriate hydrotreated product with the highest concentration of mono-aromatic derivatives, a minimum reduction on the total aromatic content, and suitable decrements of sulfur and nitrogen compounds, was achieved using a cobalt-molybdenum supported on alumina catalyst, at 330 °C, 5.5 MPa, and a liquid hourly space velocity of 1.1 h−1. Additionally, the kinetics of the HDA was studied, assuming a lump characterization into tri-, di- and mono-aromatic and aliphatic hydrocarbons, pseudo-first-order reaction rates between these conversions, and thermal losses and diffusional resistances to be undetectable.

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

“…The BTEX formation values ranged from 25.2 to 29.2 wt.%. An unexpected result contrary to the assumptions made in previous reports [4,13,14] that the higher the amounts of monoaromatic compounds, the higher the BTEX formation was obtained. It is noteworthy to mention from Figs.…”

“…Ultra-high purity hydrogen (99.99 vol.%, Infra-México) was employed in the experiments. Pemex kindly provided two LCO samples [4,14] (Table 1). The catalysts used in this work, either for HDT and HCK, were commercial catalysts that were tested in previous works [3,4,14].…”