Separation of Emulsions with Fibrous Filter-Coalescers

Area of Science:

• Petroleum Engineering
• Colloid and Surface Science
• Chemical Engineering

Background:

• Froth treatment yields water-in-diluted bitumen emulsions with small emulsified water droplets (<10 μm).
• These droplets contain chloride ions, causing catalyst deactivation and corrosion in downstream oil processing.
• Conventional methods like gravity settling and centrifugation fail to reduce water content below 2 wt %.

Purpose of the Study:

• To investigate the use of a filter-coalescer for efficient separation of water-in-bitumen emulsions.
• To develop a predictive model for emulsion filtration performance.
• To understand the mechanisms of droplet coalescence and detachment in filter-coalescers.

Main Methods:

• Utilized a filter-coalescer to promote the coalescence and separation of water-in-bitumen emulsion.
• Applied colloid filtration theory (Rajagopalan and Tien) enhanced with a coalescence probability (CP) prefactor (RTCP framework).
• Employed capillary number analysis to study droplet detachment under varying superficial velocities and bed porosities.

Main Results:

• Achieved significant reduction in water content in diluted bitumen emulsions to below 0.1 vol % after filter-coalescer treatment and gravity settling.
• The RTCP framework successfully reproduced experimental data, demonstrating its predictive capability.
• Capillary number analysis provided insights into drop detachment and size variations.

Conclusions:

• Filter-coalescers are effective for removing fine water droplets from diluted bitumen emulsions.
• The developed RTCP framework offers a potential predictive tool for emulsion filtration processes.
• Understanding droplet dynamics through capillary number analysis aids in optimizing filter-coalescer operation.