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• The physicochemical alterations in naphtha co-injection with steam were evaluated. • Physical properties of upgraded crude oil are related to structural changes. • The ANOVA evaluated the influential parameters in the naphtha co-injection/steam. • The 1H NMR parameters relate the change in viscosity in the upgraded crude oils. Steam and naphtha co-injection processes have been considered as an Enhanced oil recovery strategy to deal with current challenges in the development of heavy oil reservoirs. However, the reactions and oil physicochemical alterations in crude-solvent–water interactions under high pressure and temperature have not been dealt with in depth. Steam injection in three Colombian crude oils was studied to identify its effect on the quality of the upgraded crude oils. For this purpose, physicochemical properties such as viscosity and fraction distribution (ASTM/D-7169) were analyzed. A 23 factorial experimental design was used to know the effect of variables (270–300 °C, 48–66 h and 3–9 wt% naphtha) over viscosity reduction of upgraded crude A. Subsequently, with the best conditions crudes B and C were evaluated. The analysis of variance and Pareto chart depicted that the naphtha-vapor relationship and temperature were the variables with the greatest effect. Crude A has a viscosity of 3115.1 cP (at 45 °C), and the addition of naphtha showed viscosity reductions of about 25 to 51 %, and between 36 and 58 % for temperatures of 270 and 300 °C, for 66 h. Likewise, crude oils B and C exhibited viscosity drops of about 20 and 30 % at 270 °C, 66 h, and 9 wt% naphtha. The simulated distillation showed that the physicochemical changes were related to the conversion of the fraction with boiling points above 565 °C+. The conversions were 3.2–3.9 % and 4.5–9.1 % at temperatures of 270 and 300 °C. Average molecular parameters obtained by spectroscopy FTIR/1H NMR showed that the naphtha and steam conditions favor the transformation of complex compounds into simpler structures. These changes in physicochemical properties translate into upgraded crude oil and better results in oil recovery factors. These outcomes could be a guideline to understand the recovery mechanism during steam/naphtha injection. [ABSTRACT FROM AUTHOR]

Abstract Recent works describing the existence of an intense-blue color within the YIn 1-x Mn x O 3 solid solution due to the presence of Mn3+ cations in trigonal-bipyramidal sites have led to the interest to prepare Al-analogues with the same 5-fold non-centrosymetric coordination. In this framework, YAlO 3 structure has been recently re-examined, concluding the aluminate is indeed an oxycarbonate with the Y 3 Al 3 O 8 CO 3 stoichiometry. In this work, we observed that pure yttrium aluminate is not only obtained for fast thermal treatments below 1000 °C but with higher Al:Y ratio than 1:1. YAl 1.15 (CO 3) y O 3+δ. The corresponding YAl 1.15-x Mn x (CO 3) y O 3+δ solid solutions were successfully prepared showing dull brown colors for the low Mn-content in comparison to Yin 1-x Mn x O 3 series, confirming that the TBP coordination is lost in the aluminate, partly due to the presence of carbonate groups in the structure. Graphical abstract Image 1 Highlights • Pure hexagonal YAlO 3 can be obtained with higher Al:Y ratio than 1:1. • The corresponding oxide contains carbonate species, evidenced by TGA and IRTF. • YAl 1.15-x Mn x (CO 3) y O 3+δ solid solutions exhibit dull brown colors. • The absence of bright color is due to the loss of the 5-fold coordination for Mn. [ABSTRACT FROM AUTHOR]