Investigation of Zn-Fe-O Mixed Oxides and Their Catalytic Activity in the Refining of Heavy Oil in Supercritical Aqueous Fluid

According to PJSC Tatneft, the forecast geological and recoverable reserves of heavy oils in the Volga-Ural oil and gas basin are estimated at 4 billion tons. Profitable development of extra-viscous oil (EVO) fields is possible only in conditions of implementation of innovative energy-saving and waste-free technologies of their processing. A new promising direction in the processing of heavy EVO hydrocarbon resources into valuable hydrocarbon feedstock is their primary refining in hydrothermal fluids. The work is devoted to the study of properties of synthesized mixed Zn-Fe-О oxides and investigation of their catalytic activity under conditions simulating refining of heavy EVO hydrocarbons in hydrothermal fluid. For the first time mixed Zn-Fe-О oxides with high selectivity to asphaltene molecules in the cracking process were used as catalytic systems for refining. Synthesis of mixed Zn-Fe-О oxides was carried out by co-precipitation of preliminary hydroxide forms from aqueous solutions containing corresponding Zn2+ and Fe3+ cations. According to the X-ray diffraction analysis data, the influence of the molar ratio of metal cations Zn2+/Fe3+ in aqueous solution on the phase composition, crystallinity and lattice parameters of the obtained mixed Zn-Fe-О oxides was established. According to IR spectroscopy data, the presence of spinel phase ZnFe2O4 in the composition of mixed Zn-Fe-О oxides was recorded. As a result of experimental studies of refining of heavy EVO in hydrothermal fluid in the presence of the obtained mixed Zn-Fe-О oxides, the influence of their structure on the composition of the final product was established.