Composition of aquathermolysis catalysts forming in situ from oil-soluble catalyst precursor mixtures

Increasing efficiency of thermal recovery methods of heavy oil through injection of destructive hydrogenation catalysts precursors is a relevant task. In this paper the composition and properties of the active binary catalysts, which formed from a mixture of oil-soluble iron-, nickel- and copper-based precursors have been studied by XRD, Mössbauer spectroscopy, SEM, EDX-mapping methods. Moreover, the efficiency of a mixture of the corresponding metals in reducing the content of heavy components (SARA) of heavy crude oil from Ashal'cha field (Republic of Tatarstan) have been investigated. Mössbauer spectroscopy and EDX-mapping detected the formation of not only spinel ferrites MFe2O4 (where M = Ni or Cu), but also individual oxides. Moreover, in case of nickel-based catalyst three phases are formed: magnetite FeO⋅Fe2O3, spinel ferrite NiFe2O4 and superparamagnetic finely dispersed phase of iron oxides (and probably nickel oxides). According to XRD results, the oxides formed in the first stage transform into nonstoichiometric spinel ferrites Cu0.86Fe2.14O4 and Ni1.43Fe1.7O4 under hydrothermal influences. It is related with the thermodynamically beneficial processes of conversion of this specific phase composition. Based on the SARA and elemental analysis of the initial and converted oil, it was found that catalytic aquathermolysis decreases the content of asphaltenes and resins (about 45%) in the presence of catalyst nanoparticles, which indicates an improvement in the quality of the heavy oil.