Separation & Coalescing Filter

In many industrial processes, contaminants are not always solid particles. They may exist as fine liquid droplets, aerosols, emulsified water, entrained oil, or condensate mist.

Traditional particle filtration alone cannot effectively remove these dispersed liquid phases. This is where coalescing and separation technology becomes essential.

What is Coalescing?

Coalescing is the process of merging fine dispersed droplets into larger droplets that can be more easily separated from the flowing stream.

As contaminated fluid passes through engineered media:

• Tiny droplets contact fibers or porous surfaces
• Droplets collide and merge
• Droplet size increases
• Larger droplets separate by gravity or downstream separator stage

This principle is widely used in:

• Oil removal from compressed air
• Water removal from diesel fuel
• Mist removal from gas streams
• Condensate removal from natural gas
• Oil / water treatment systems

What Controls Separation Efficiency?

1. Droplet Size Distribution

Larger droplets separate more easily, while sub-micron emulsions are more difficult to remove.

2. Interfacial Tension (IFT)

Low interfacial tension systems are harder to separate because droplets remain more stable and less likely to merge.

3. Viscosity

Higher viscosity slows droplet movement and reduces separation speed.

4. Density Difference

Greater density difference between phases improves gravity separation performance.

5. Flow Velocity

Excessive flow velocity can re-entrain separated droplets back into the process stream.

Two-Stage Engineering Principle

Most effective systems use two-stage separation design:

Stage 1: Coalescing Media

Capture fine droplets and promote droplet growth through repeated collision and merging.

Stage 2: Separator Media / Chamber

Remove enlarged droplets from the flow stream through gravity settling, vane separation, or dedicated separator elements.

Why Standard Filters Fail

Conventional particulate filters are designed for solids retention and may perform poorly in liquid-phase separation service.

• Blind quickly when exposed to liquid loading
• Retain liquid internally
• Create rapid pressure drop increase
• Cannot effectively break emulsions

Coalescers are engineered specifically for liquid-phase behavior, not only particle capture.

CMI Engineering Capability

• Liquid-liquid coalescers
• Gas-liquid coalescers
• Fuel water separators
• Natural gas mist eliminators
• Custom vessel internals
• Replacement coalescer elements

Typical Industries

• Oil & Gas
• Petrochemical
• Aviation Fuel
• Compressor Systems
• Chemical Processing
• Power Generation

CMI Process Focus

At CMI, coalescing solutions are selected based on fluid properties, droplet behavior, operating pressure, temperature, and target separation efficiency. We focus on practical process performance rather than generic filter sizing.