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Petroleum heavy vacuum gas oil (HVGO) containing 10 wt.% of petroleum wax was hydrocracked at 390–430 °C and under the pressure of 18 MPa over a Ni W/amorphous silica-alumina catalyst in a continuous-flow fixed-bed reactor. The hydrocracking of a reference feed (neat HVGO) was carried out under the same reaction conditions. The physico-chemical properties of primary products obtained via laboratory atmospheric-vacuum distillation (heavy naphtha, middle distillates and distillation residue) were evaluated. Most products prepared from the mixed feedstock had a similar or lower density and sulfur content than the products obtained from the hydrocracking of the neat HVGO. The heavy naphtha fractions obtained from mixed feedstock contained slightly more n-alkanes and iso-alkanes and less naphthenes and aromatics. Similarly, middle distillates obtained from the mixed feedstock contained slightly more n-alkanes and less aromatics and had cetane index higher by up to 2 units.

Due to the growing restrictions on the content of aromatic compounds by the European legislation in motor fuels and at the same time the need for higher quality fuels (minimizing the presence of contaminants and hazardous products to health), it has become necessary to increase processes that can maximize the number of octane in gasoline. This manuscript is aimed to provide current trends and processes related to isomerization, alkylation and etherification processes to improve gasolines as final product. Examples provided include the isomerization of light n-alkanes into iso-alkanes or the alkylation, in which the preferred olefin is the methylbutilene and i-butane to produce a high octane number gasoline. Currently, there are two main commercial processes for alkylation processes (hydrofluoric and sulfuric acid technologies). Other incoming suitable process is the etherification of iso-olefins to bio-ethers (the European Union have as a minimum target of biofuel content in fuels of 10% in 2020). The refiners are recently investing in the production of bio-ETBE (ethyl tertiary butyl ether) and other products as additives using bio-ethanol and olefins. Commercial and new potential catalysts for all these processes are currently being used and under investigation.

The original version of the article was published in Cent. Eur. J. Chem. 12(1) (2014) pp. 1–13. Unfortunately, the original version of this article contains some mistakes in the text: The caption of Figure 7. A fixed bed unit converted to the UOP Par-Isom Process™Par Isom Process should be written as Par-Isom Process™everywhere in the text LCC should be written as LLC