Experimental Considerations for Proper Development of Aquathermolysis Tests in Batch Reactor Systems

Abstract

Steam-based technologies are promising procedures with great potential for the recovery of heavy oil reserves. Particularly, catalytic aquathermolysis has been identified as a relevant technology for the permanent upgrading of heavy crude oil to increase the recovery factor. This technology requires appropriate experimentation for evaluation of the effect of operational conditions on product yield and quality and catalyst performance, and to determine reaction kinetics and mechanisms. Consequently, the procedures used to generate, interpret, and analyze the experimental data required for optimizing the aquathermolysis process need to be properly defined and applied. This work reports an exhaustive review of experimental results reported in the literature on diverse upgraded oil samples. The effect of operating reaction parameters, such as temperature, oil/water ratio, time, and catalyst dosage, was discussed in detail. Based on experimental results, some behaviors in gas production and viscosity reduction are highlighted and explained for the development of future studies. It was concluded that the upgrading of crude oil is mainly influenced by the reactivity of the chemical compounds involved, and a detailed analysis of the reaction system is required for the experimental development and scale-up.

New Approach to Simulate Long-Term In Situ Aquathermolysis Reaction Combining Noncatalytic and Catalytic Kinetic Models

“…The yield of heavy fractions is reduced with reaction time until they start to reach equilibrium, while the content of light fractions is raised with time. This is because the conversion of all fractions in crude oils depends on their composition and reactivity . As the amount of As and Re is lowered, the number of reactive molecules (poly condensed aromatic ring containing heteroatoms, especially sulfur compounds) is reduced, hindering the conversion of these fractions.…”

The Effect of Thermal Steam Treatment Duration with Metallic Sodium Nanoparticles on Heavy Oil Upgrading

“…Potentiometric titration results indicate that in the presence of a sodium nanoparticle suspension during aquathermolysis, there is an average halving of the mercaptan sulfur content. This decrease in mercaptan sulfur content, attributed to the interaction forming sodium mercaptides, , subsequently migrates into the water phase of the oil emulsion postreactor.…”

Kinetics of Non-Catalytic Aquathermolysis of Heavy Crude Oil in the Presence of a Hydrogen Donor

“…Due to the depletion of conventional oil reserves and increasing energy consumption worldwide, the recovery and upgrading of heavy crude oil resources have received more attention from oil companies and research centers. Steam injection techniques (cyclic steam stimulation, steam flooding, steam-assisted gravity drainage) are the most applied methods for heavy crude oil production, where the application of some catalytic precursors and solvents has allowed for increasing significantly the recovery factor by reducing the content of macromolecules, such as asphaltenes and resins, and increasing the yield of light fractions. , During these processes, the viscosity of heavy crude oil is reduced by composition and structure changes of oil compounds due to a series of reactions in the presence of steam (aquathermolysis), involving cleavage of alkyl chains, carbon-heteroatom bonds, hydrogenation, and heteroatom removal, where active hydrogen is produced in situ by water–gas shift (WGS) reaction and water dissociation. , However, the efficiency of water conversion into hydrogen is limited for the accomplishment of high degrees of hydrogenation of organic substances, and condensed structure compounds with free radicals lead to the formation of secondary resins and asphaltene molecules by polyaddition reactions, resulting in viscosity regression. , In order to increase the performance in these processes and provide additional active hydrogen in the reaction system capable of saturating the formed free radicals, some solvents with hydrogen donation capacity via dehydrogenation/hydrogenation mechanisms (tetralin, decalin, and cyclohexane) have been studied to favor the production of light compounds and inhibit polyaddition reactions. − Consequently, the concentration of free radicals in the reaction system decreases, inhibiting the recombination of generated molecule radicals and thus the viscosity rebounding of heavy crude oil. , …”