Effect of Ligand Structure on the Kinetics of Heavy Oil Oxidation: Toward Biobased Oil-Soluble Catalytic Systems for Enhanced Oil Recovery

Optimizing In Situ Combustion with Manganese (II) Oxide Nanoparticle-Catalyzed Heavy Oil Oxidation

The combustion front is a crucial parameter in determining the efficiency of in situ combustion techniques during enhanced oil recovery. Nowadays, catalytic systems are widely believed to be an efficient tool to stabilize the combustion front. This study aimed to investigate the synthesis and catalytic activity of manganese (II) oxide nanoparticles in the high-temperature oxidation of heavy oils. The synthesis and catalytic activity of manganese (II) oxide nanoparticles in the high and low-temperature oxidation regions of heavy oil were investigated in this study. The obtained nanoparticles were characterized and studied by using X-ray powder diffraction (XRPD), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), transmission electron microscopy (TEM), thermogravimetric analysis (TG), nitrogen adsorption and desorption measurements, and differential scanning calorimetry (DSC) thermal analysis combined with the Kissinger isoconversional method. The obtained results showed that the synthesized nanoparticles had an average size of 17 ± 4 nm and a specific surface area of 38.2 ± 0.1 m2 g−1, with a pore size distribution of ~8 nm. The low and high-temperature oxidation processes’ activation energies were found to be 98.9 ± 0.7 kJ/mol and 151.9 ± 0.6 kJ/mol, respectively, in the presence of nanoparticles. However, these parameters were found to be equal to 110.1 ± 1.8 kJ/mol and 142.8 ± 8.3 kJ/mol, respectively, in the absence of nanoparticles. These data were processed further by calculating the corresponding reaction rates. The obtained results indicated that the rate of heavy oil oxidation was higher in the presence of the synthesized nanoparticles, which could play a critical role in stabilizing the combustion front in the in situ combustion process.

Changes in Heavy Oil Saturates and Aromatics in the Presence of Microwave Radiation and Iron-Based Nanoparticles

Our knowledge of electromagnetic heating’s effect on heavy oil upgrading is largely based on very limited data. The aim of the present research was thus to study in detail the effect of microwave exposure in the absence and presence of nanosized magnetite on the composition of heavy oil. The obtained data reveal that the use of nanosized magnetite improves not only microwave radiation application as a result of its absorption and release of thermal energy but also that these nanoparticles have a catalytic ability to break carbon–heteroatom bonds in the composition of resins and asphaltene molecules. In fact, the overall reduction in asphaltenes or resins does not always adequately describe very important changes in asphaltene composition. Even a small fraction of broken carbon–heteroatom bonds can lead to an increase in the mobility of asphaltenes. Moreover, this study has shed light on the important evidence for asphaltenes’ transformation, which was found to be the formation of light aromatic compounds, such as alkylbenzenes, naphthalenes and phenanthrenes. These compounds were fixed in the composition of the aromatic fraction. We believe that these compounds could be the fragments obtained from asphaltenes’ degradation. The evidence from this study points toward the idea that asphaltenes’ destruction is crucial for increasing oil mobility in the reservoir rock during its thermal stimulation.

Thermal Behavior of Heavy Oil Catalytic Pyrolysis and Aquathermolysis

There is still considerable controversy surrounding the mechanisms, thermodynamics, and kinetics of heavy oil aquathermolysis and pyrolysis processes. The present paper aims to widen our knowledge about the effect of iron tallates on pyrolysis and aquathermolysis of Cuban heavy oil. The obtained SARA (S: saturates, A: aromatics, R: resins, A: asphaltenes) analysis has shown a significant increase in light hydrocarbon content during aquathermolysis. Moreover, the elemental analysis has indicated an increase in C and H content by almost 4% and 6%, respectively, with a significant decrease in S and O content by up to 23% in the presence of iron tallates. These results have been further confirmed by infrared spectrometry. The obtained IR data indicated that asphaltene and resin compounds transform into light hydrocarbons after aquathermolysis. On another hand, the activation energy of heavy oil pyrolysis decreased in the presence of the utilized catalyst; meanwhile, the reaction rate increased, especially in the temperature range of 200–480 °C, which may validate a significant effect of the used catalyst in real conditions. Moreover, the obtained thermodynamic data showed a decrease in the enthalpy and entropy of activation of oil pyrolysis in the presence of iron tallates. Our results are encouraging in terms of energy consumption, optimization, and process control and should be validated by a larger sample size.

Microwave Radiation Impact on Heavy Oil Upgrading from Carbonate Deposits in the Presence of Nano-Sized Magnetite

The present paper reports experiments on microwave heating of a carbonate oil-containing rock sample in the presence and absence of an iron-magnetite-based nanocatalyst. It has been shown that the used catalyst improves the processes of destructive hydrogenation of resins and asphaltenes compounds in the oil. The chemical reactions analysis demonstrated a decrease in asphaltenes content and in their molecular weight, which increases the filtration capacity of the oil fluid in the reservoir rock porous medium. Moreover, the content of non-extractable organic matter in the rock sample after experiments and after oil extraction was determined. It has been found that the absence of the catalyst causes the least increase in the content of non-extractable organic matter in the rock. This fact is related to the intensive processes of resinous-asphaltene compounds destruction especially at the level of peripheral groups which are the most condensed fraction, and hence leads to a decrease in their solubility in the organic medium and eases their adsorption on the mineral skeleton surface.

A Thermal Study on Peat Oxidation Behavior in the Presence of an Iron-Based Catalyst

Peat is a resource used for heat and energy, particularly in countries where peat is abundant and conventional fuels are not available. Some countries have made extensive use of peat resources to produce electricity and heat in addition to light hydrocarbons. By doing so, they were able to reduce the cost of importing fossil fuels. To the best of our knowledge, there is a lack of a detailed description of the peat oxidation process in the presence of other substances. Herein, the process of peat oxidation was studied in-depth by means of thermal analysis in the presence of iron tallate acting as a catalytic agent. Differential scanning calorimetry and thermogravimetric analysis demonstrated an oil-like oxidation behavior during the combustion of the used peat. The process of peat oxidation includes two main regions: low-temperature oxidation (LTO), which occurs during the oxidation of light hydrocarbons, followed by the so-called high-temperature oxidation (HTO), which includes the oxidation of the obtained coke-like product. Moreover, the application of non-isothermal kinetics experiments based on the isoconversional and model approach principle have confirmed the role of 2% iron tallate in peat mass by improving the oxidation rate at low- and high-temperature oxidation (HTO) regions. The results obtained from this study have proven that the added catalyst improves efficiency with regards to the energy activation in the process by leading to its significant decrease from 110.8 ± 7.8 kJ/mol to 81.8 ± 7.5 kJ/mol for LTO and from 157.8 ± 19.1 kJ/mol to 137.6 ± 9.3 kJ/mol for HTO. These findings clearly confirm the improvement in the rate of the process by shifting the LTO and HTO peaks to lower regions in the presence of the catalyst. These results further emphasize the possible impact which could be generated by the application of thermally enhanced oil recovery methods on peat development and exploitation.