Dynamics and Structure of Bitumen-Water Mixtures

Area of Science:

• Petroleum Geochemistry
• Materials Science
• Computational Chemistry

Background:

• Bitumen, a complex hydrocarbon mixture, can interact with water, affecting its properties.
• Understanding these interactions is crucial for various industrial applications, including oil recovery and material processing.

Purpose of the Study:

• To investigate the effects of water content on Cooee bitumen properties using molecular dynamics simulations.
• To analyze the behavior and distribution of water molecules within the bitumen matrix.

Main Methods:

• Molecular dynamics simulations were employed to model bitumen-water systems with varying water content (up to 4% mass).
• Analysis focused on cohesive energy density, interaction energies, volume changes, and droplet formation.

Main Results:

• Cohesive energy density decreases with increasing water content, primarily due to increased system volume outweighing interaction energy changes.
• Water molecules aggregate into droplets within the bitumen, with size and distribution dependent on temperature.
• These water droplets are predominantly found near saturates molecules in the bitumen.
• Water dynamics in bitumen are significantly slower than in pure water, governed by droplet diffusion.

Conclusions:

• Water addition impacts bitumen's cohesive energy density through volume expansion rather than altered asphaltene interactions.
• Water forms stable droplets in bitumen, influencing its macroscopic properties and molecular mobility.
• The diffusion of water droplets, not individual molecules, dictates water's slow dynamics in bitumen.