The components of petroleum asphaltenes exhibit complex bridged structures comprising sulfur, nitrogen, aromatic, and naphthenic groups linked by alkyl chains. These components aggregate in crude o...

Supramolecular Assembly Model for Aggregation of Petroleum Asphaltenes

With the ever increasing demand for energy to meet the needs of growth in population and improvement in the living standards in particular in developing countries, the abundant unconventional oil reserves (about 70% of total world oil), such as heavy oil, oil/tar sands and shale oil, are playing an increasingly important role in securing global energy supply. Compared with the conventional reserves unconventional oil reserves are characterized by extremely high viscosity and density, combined with complex chemistry. As a result, petroleum production from unconventional oil reserves is much more difficult and costly with more serious environmental impacts. As a key underpinning science, understanding the interfacial phenomena involved in unconventional petroleum production, such as oil liberation from host rocks, oil–water emulsions and demulsification, is critical for developing novel processes to improve oil production while reducing GHG emission and other environmental impacts at a lower operating cost. In the past decade, significant efforts and advances have been made in applying the principles of interfacial sciences to better understand complex unconventional oil-systems, while many environmental and production challenges remain. In this critical review, the recent research findings and progress in the interfacial sciences related to unconventional petroleum production are critically reviewed. In particular, the chemistry of unconventional oils, liberation mechanisms of oil from host rocks and mechanisms of emulsion stability and destabilization in unconventional oil production systems are discussed in detail. This review also seeks to summarize the current state-of-the-art characterization techniques and brings forward the challenges and opportunities for future research in this important field of physical chemistry and petroleum.

Interfacial sciences in unconventional petroleum production: from fundamentals to applications

Most crude oils contain traces of vanadium, which cause significant detrimental impact during catalytic conversion and combustion. The concentrations in bitumen and vacuum residue are generally much higher, which poses a problem for the economical upgrading of these feedstocks. These problems are relevant since the world reserves of conventional light oils are dwindling and being replaced by an increasing amount of heavier feedstocks. In this article, the current understanding of the distribution and form of vanadium compounds within vacuum residue is critically discussed. The implications of this chemistry on prospects for new separation methods, other than deasphalting, are considered. Although only a small fraction of the vanadium is contained within the polar resin fraction (i.e., maltenes), this fraction has been most often characterized to determine the chemical form of the vanadium compounds. Various spectroscopic techniques have been used to determine that these resin soluble vanadium compounds ex...

Chemistry and Association of Vanadium Compounds in Heavy Oil and Bitumen, and Implications for Their Selective Removal

Stability mechanism of W/O crude oil emulsion stabilized by polymer and surfactant

Overview on petroleum emulsions, formation, influence and demulsification treatment techniques

The ability to stabilize water-in-oil (W/O) emulsions for six studied asphaltene subfractions is dependent on their solubility rather than on their concentration, polarity, molecular weight, or other parameters. Paraffinic froth treatment technology recently introduced in the oil sand industry yields a clean bitumen product (<0.1 wt % water and <0.1 wt % solids) at a solvent-to-bitumen ratio above a critical value, which corresponds to the onset of asphaltene precipitation. Six subfractions of Athabasca bitumen asphaltenes were obtained by precipitation with a gradually increasing heptane-to-bitumen (H/B) ratio, from 1.25 to 40. The properties of the asphaltene subfractions obtained were investigated by elemental analysis, Fourier transform infrared (FTIR) and ultraviolet-visible (UV−vis) spectroscopy, and vapor pressure osmometry (VPO). There were no significant differences in the molecular masses of the six asphaltene subfractions. However, the aromaticity and the metalloporphyrin (vanadyl) content in t...

Investigation of Subfractions of Athabasca Asphaltenes and Their Role in Emulsion Stability

The invention relates to a method of treating a liquid hydrocarbon (e.g. heavy oil, bitumen, etc.) containing naphthenic acid(s) or other corrosive acids in order to partially or fully convert such acids into non-corrosive compounds. The method comprises adding an alkylating agent to the hydrocarbon, bringing the hydrocarbon into contact with an aqueous liquid containing an alkaline compound and a phase transfer catalyst to form an immiscible two-phase system, maintaining the contact to allow conversion of the acid to non-corrosive oil-soluble esters, and separating the aqueous phase from the liquid hydrocarbon. Acids, particularly naphthenic acids, are highly corrosive to plant and equipment and the method enables such acids to be converted to non-corrosive compounds in an economic manner.

Jan Czarnecki

Papers

Investigation of Subfractions of Athabasca Asphaltenes and Their Role in Emulsion Stability

Treatment of hydrocarbons containing acids