Improving the quality of low octane hydrocarbon fractions under conditions of catalytic processing on aluminum-silicon catalysts

Abstract

The main challenge today is to find new alternative energy sources. Reduction of oil, gas and coal production can be achieved through the rational use of biomass as a raw material for fuels and lubricants. Thermochemical treatment of biomass allows to obtain raw materials for a number of processes, in particular the separation of hydrocarbon components and their catalytic treatment allows to obtain alternative components for motor fuels. The main advantage of using hydrocarbon fractions from biomass is that they are completely free of sulfur- or nitrogen-containing compounds that play the role of catalytic poisons. Catalytic studies were performed in a flow reactor at a charged catalyst volume of 30 cm³, a reaction zone temperature of 350 ± 5 °C and a pressure of 0.1 MPa. The feedstock was fed to the reaction zone using a pump at a constant rate of 1 h-1. The direction of supply of raw materials from top to bottom. In this work it is shown that industrial aluminosilicates are structural compounds (Cat.25, Cat.38, Cat.50, Cat.80) and show catalytic properties in the cracking process, which is reflected in the increase of octane number from 8 to 20 units. The higher their cracking activity, the more gaseous products are formed and the fractional composition changes in the direction of isomeric hydrocarbons, which is confirmed by gas chromatographic analysis. According to the amount of gas phase and the composition of liquid products, it should be noted that the most active catalyst was the sample Cat.25. This efficiency is related to the chemical composition and methods of synthesis of the presented catalysts. The latter by their nature contain cations of aluminum (Al3+) and silicon (Si4+), which certainly affects the formation of Bronsted acid centers, which are responsible for the cracking process. In turn, catalysts of the type Cat.1 and Cat.2 with a significant content of aluminum and no catalytic effect can be characterized as a mechanical mixture of these basic oxides, and not an aluminosilicate matrix with a certain structure. Based on the obtained results, renewable biomass is a potential source for obtaining hydrocarbon fractions, which after catalytic treatment processes can serve as high-quality high-octane components of alternative fuels.