New Pathways for Asphaltenes Upgrading Using the Oxy-Cracking Process

Abstract

Solvent deasphalting of the bottom of vacuum distillation columns (vacuum residue, VR) is a process practiced worldwide. In Northern Alberta, a solvent deasphalting plant was designed to process up to 4000 tons/day of the asphaltenic pitch. Asphaltenes oxy-cracking in liquid phase could be a new approach to asphaltenes upgrading and conversion into valuable chemicals. Oxy-cracking is a combination of oxidation and cracking in basic aqueous media at moderate temperatures (170–225 °C) and pressures (300–500 psi). This process could act very selectively producing smaller amounts of greenhouse gases like CO2, thus being considered environmentally friendly. In this work, a mild oxy-cracking treatment of C5-asphaltenes solid from Athabasca vacuum residue was investigated. The reaction kinetics and possible reaction mechanism for C5-asphaltenes oxy-cracking in water under alkali conditions were studied. Products solubilized under different severities were characterized using Fourier transform infrared and nuclear magnetic resonance spectroscopies, simulated distillation, elemental analysis, and ultraviolet–visible spectrophotometry to investigate the structure of solubilized products and changes in asphaltenes structures after the reaction. A model based on sequential-parallel reactions from the asphaltenes to water-soluble products and CO2 was found to describe the process successfully. Products of oxidized functionalities like carboxylic acids, their salts, methyl ethers and esters, and sulfur-oxidized forms plus phenolics were determined as the most significant fractions soluble in water. Solubilization of asphaltenes in water could also decrease challenges regarding facilities and pipelines plugging.

Enhancement of petroleum coke thermal reactivity using Oxy‐cracking technique

“…The oxy‐cracked materials were found to contain low molecular weight compounds that are believed to be easier to oxidize . Additionally, it has been suggested in our previous work on petcoke that the oxy‐cracking process might be an effective route for demineralization and desulphurization of feedstocks …”

“…Oxy‐cracking of petcoke via sequential oxidation and cracking reactions under alkaline conditions might be a promising technique to generate a new type of material that can be used as a fuel, with low sulphur, nitrogen, and metal contents. The oxy‐cracking process was recently reported as an alternative‐practical approach for partially oxidizing and solubilizing heavy residual feedstock like asphaltenes and petcoke into alkaline media with minimal emissions of CO 2 at mild reaction conditions (170–250 °C and 5000 kPa) . This oxy‐cracking reaction was motivated by Ashtari et al for solubilizing n‐C 7 asphaltenes in alkaline medium, which then could be upgraded into light products through hydroprocessing reaction as reported by Haghighat et al Using quinolin‐65 (Q‐65) as a model molecule for residual feedstock, our group has carried out computational modelling to understand the oxy‐cracking mechanism at the molecular level using state‐of‐the‐art ab initio methods, under conditions similar to those performed in the experimental part .…”

“…The oxy-cracking process was recently reported as an alternative-practical approach for partially oxidizing and solubilizing heavy residual feedstock like asphaltenes and petcoke into alkaline media with minimal emissions of CO 2 at mild reaction conditions (170-250°C and 5000 kPa). [20][21][22][23][24] This oxy-cracking reaction was motivated by Ashtari et al [25] for solubilizing n-C 7 asphaltenes in alkaline medium, which then could be upgraded into light products through hydroprocessing reaction as reported by Haghighat et al [26] Using quinolin-65 (Q-65) as a model molecule for residual feedstock, our group has carried out computational modelling to understand the oxy-cracking mechanism at the molecular level using state-of-the-art ab initio methods, under conditions similar to those performed in the experimental part. [26] This provided an insight on the different possible reaction pathways, which is also confirmed by our recent study on the oxy-cracking of metformin-an anti-diabetic agent and one of the most prescribed pharmaceutical compounds worldwide.…”

“…[21] Additionally, it has been suggested in our previous work on petcoke that the oxy-cracking process might be an effective route for demineralization and desulphurization of feedstocks. [20,21] The main goal of this study is to explore the thermal behaviour of these oxy-cracked products and compare them with the virgin petcoke. Additionally, we studied the combustion parameters of oxy-cracked petcoke, virgin petcoke, and their mixture.…”

Aluminum Oxide Nanoparticles for Highly Efficient Asphaltene Separation from Crude Oil Using Ceramic Membrane Technology

“…The precipitation of asphaltenes makes various issues such as the blockage of crude oil extraction and the transport pipes and also the pollution of ecosystems. In addition, precipitated asphaltene increases the viscosity of crude oils, negatively impacting production (Ashtari et al, 2016a;Ashtari et al, 2016b;Goual et al, 2011;Kaminski et al, 2000).…”