Use of deuterated water to prove its role as hydrogen donor during the hydrothermal upgrading of oil shale at supercritical conditions

Abstract

This paper corroborates the capability of supercritical water to generate active hydrogen that interact with the different fractions involved in unconventional feedstocks such as oil shale during the hydrothermal reactions by using supercritical deuterated water (SCDW). Experiments were conducted in an autoclave reactor at a temperature of 380 ºC and a time of 1–12 h. The products were assessed using various methods. The findings indicate that 15.30% of deuterium (D) was involved in the reaction of synthetic oil production and that oil samples are characterized by the presence of heteroatoms (N and O) most derived from kerogen. It found that the generation of synthetic oil is perturbed by carbonate species and a maximal yield of 16.78% is reached at 6 h. FTIR revealed that during hydrothermal upgrading of oil shale, the conversion of resins consumes more molecules of D than asphaltenes. According to EPR, Fe²⁺ and Mn²⁺ particles haven't played much role in the upgrading process.