Reducing the environmental impact of aluminum production through the use of petroleum pitch

Abstract

This study is aimed at developing a technology for obtaining petroleum pitch as a binder for anode mass used in the electrolytic production of aluminum from fuel oils of catalytic liquid-phase oxidative oil cracking. A review of published data on the existing methods for obtaining petroleum pitch and its properties is carried out in order to define research directions. A method for producing petroleum pitch by catalytic liquid-phase oxidative cracking of crude oil using heterogeneous metal complex catalysts is proposed. The process of petroleum pitch production is shown to undergo several stages, including homogenization of fuel oil and modifying additives; oxidative cracking of fuel oil during heating of homogenized fuel oil in a furnace; catalytic liquid-phase oxidative cracking of fuel oil with removal of distillates; rectification of light fractions; condensation of distillates; collection of light oil products; oxidation of bottom residues by air and steam; removal of oxidation distillates and petroleum pitch; and pitch pelletizing. According to the conducted comparison of the as-obtained petroleum pitch with the B-1 coal tar pitch produced by the Altai Koks JSC, the proposed material meets the technological requirements of the Krasnoyarsk Aluminum Plant of the RUSAL company. In terms of sulfur content, the proposed petroleum pitch is superior to coal tar pitch. The experiments conducted at an aluminum plant showed the petroleum pitch to contain no harmful polyaromatic hydrocarbons, in particular, carcinogenic benz(a)pyrene.  Therefore, replacement of coal tar pitch with petroleum pitch could provide technological and environmental advantages for primary aluminum producers, as well as for enterprises producing various carbon materials.