Influence of Pressure on Product Composition and Hydrogen Consumption in Hydrotreating of Gas Oil and Rapeseed Oil Blends over a NiMo Catalyst

This study describes the co-hydrotreating of mixtures of rapeseed oil (0–20 wt%) with a petroleum feedstock consisting of 90 wt% of straight run gas oil and 10 wt% of light cycle oil. The hydrotreating was carried out in a laboratory flow reactor using a sulfided NiMo/Al2O3 catalyst at a temperature of 345 °C, the pressure of 4.0 and 8.0 MPa, a weight hourly space velocity of 1.0 h−1 and hydrogen to feedstock ratio of 230 m3∙m−3. All the liquid products met the EU diesel fuel specifications for the sulfur content (<10 mg∙kg−1). The content of aromatics in the products was very low due to the high hydrogenation activity of the catalyst and the total conversion of the rapeseed oil into saturated hydrocarbons. The addition of a depressant did not affect the cold filter plugging point of the products. The larger content of n-C17 than n-C18 alkanes suggested that the hydrodecarboxylation and hydrodecarbonylation reactions were preferred over the hydrodeoxygenation of the rapeseed oil. The hydrogen consumption increased with increasing pressure and the hydrogen consumption for the rapeseed oil conversion was higher when compared to the hydrotreating of the petroleum feedstock.

Thermal Polycondensation Process and Oil Furnace Production

The article discusses the methods of obtaining petroleum pitch of thermal polycondensation. The main attention is paid to the characteristics of petroleum pitch, its properties, its comparison with coal-tar pitch, the advantages of petroleum pitch in comparison to coal-tar pitch, the processes of production of petroleum pitch by thermal polycondensation are given. Three promising technologies for the production of petroleum pitch have been identified: thermal polycondensation of cracking residue, high-temperature thermal polycondensation of petroleum feedstock and thermal polycondensation of pyrolysis resin according to a two-stage scheme. Methods of obtaining petroleum pitch in laboratory conditions, such as thermal polycondensation under pressure and heat treatment under reduced pressure, are presented. The urgency and feasibility of developments for the creation of petroleum pitch and the introduction of thermopoly-condensation processes in Russia is emphasized.

Bio-oil transformation into 2nd generation biofuels

The article summarized the possible transformations of pyrolysis bio-oil from lignocellulose into 2nd generation biofuels. Although a lot has been published about this topic, so far, none of the published catalytic pro-cesses has found commercial application due to the rapid deactivation of the catalyst. Most researches deal with bio-oil hydrotreatment at severe conditions or its pro-cessing by catalytic cracking to prepare 2nd generation biofuels directly. However, this approach is not commercially applicable due to high consumptions of hydrogen and fast catalyst deactivation. Another way, crude bio-oil co-processing with petroleum fractions in hydrotreatment or FCC units seems to be more promising. The last approach, bio-oil mild hydrotreatment followed by final co-processing with petroleum feedstock using common refining processes (FCC and hydrotreatment) seems to be the most promising way to produce 2nd generation biofuels from pyrolysis bio-oil. Co-processing of bio-oil with petroleum fraction in FCC increases conversion to gasoline and, thus, it could be a preferable process in the USA. Otherwise, co-hydrotreatment of hydrotreated bio-oil with LCO leads not only to the reduction of hydrogen consumption but also to the conversion preferably to diesel. This process seems to be more suitable for Europe. Further research on bio-oils upgrading is still necessary before the commercialization of the bio-oil conversion into biofuels suitable for cars. However, the first commercial bio-refinery that will convert bio-oil into biofuel for marine transport is planned to be built in the Netherlands.

Mathematical Modelling and Simulation of a Trickle-Bed Reactor for Hydrotreating of Petroleum Feedstock

In this work, a model for a trickle-bed reactor for catalytic hydrotreating (HDT) of oil fractions is developed and simulations are performed to investigate its behavior. The model considers dynamic, one-dimensional plug-flow to describe a heterogeneous, adiabatic trickle-bed reactor. It takes into consideration the main reactions present in the HDT process: hydrodesulfurization (HDS), hydrodenitrogenation (HDN), and hydrodearomatization (HDA) with a reconstructed petroleum feedstock using a practical approach of generation of pseudo-components by dividing the boiling point curves of the feedstock. The model is solved using the method of lines with a finite difference scheme for discretization in the axial direction and simulations are performed for an industrial hydrotreating unit to evaluate the behavior of the system under different conditions and assumptions e. g. related to the linear gas velocity. A study of the dynamics is carried out to investigate the behavior of the system with a change in the sulfur compound concentration of the feed. In addition, a sensitivity analysis of the most relevant model parameters is performed.