Liquid/Liquid Coalescers

Pall’s liquid/liquid coalescers efficiently remove free water and particulate contamination in various applications in the oil and gas, and chemical industries to save costs and extend the life of the equipment.

Pall offers a wide range of liquid-liquid coalescers to choose from.

  • PhaseSep® EL Coalescers

Ideal for working with aggressive chemicals at high temperatures, PhaseSep EL coalescing filters can virtually separate any liquid-liquid emulsion.


  • AquaSep® Coalescers

Suitable for working with non-aggressive chemicals at normal temperatures, AquaSep coalescers effectively separate water from the hydrocarbon stream.


  • Ultipleat® Diesel Plus Filters

The Ultipleat Diesel Plus filters offer advanced water and particulate removal from diesel within a single filter element while offering high dirt holding capacity and long filter life.


  • Retrofit Coalescers

Pall's retrofit filters and coalescers work as direct replacements for competitors elements. The products are reliable and offer improved efficiency.

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The inability to efficiently separate liquid/liquid emulsions can be a very costly problem in the oil, gas, and chemical industries. Liquid contamination can cause final products to be off-specification, rapid deactivation of downstream catalysts, corrosion of downstream storage facilities, and increased costs for wastewater treatment. Breaking stable emulsions can be difficult depending on the physical properties of the oil, water, and surfactant system.


Pall’s liquid/liquid coalescers offer effective liquid/liquid separations. The coalescer separator breaks emulsions into two phases using a highly efficient liquid/liquid separation method that utilizes a polymeric material that can handle very low interfacial tension (IFT) and does not disarm with surfactants. The prefilter provides particulate control for long coalescer life and optimizes operating costs.


The liquid/liquid coalescers provide free water removal to a level as low as 15 ppmv and are available in horizontal and vertical orientations to suit budgetary, size, weight, and footprint needs. While the vertical configuration provides a smaller capital footprint, the horizontal configuration offers easier change-out, higher flow, and lower vessel costs.


Why choose Liquid-Liquid Coalescers? 


Pall’s liquid/liquid coalescers provide several benefits, including:

  • Improved fluid quality, consistency, and value
  • Lower operating, disposal, and maintenance costs
  • Lower separation costs
  • Prevention of catalyst deactivation in downstream processes
  • Reduced corrosion problems in downstream equipment 
  • Prevention of disarming, thereby increasing service life 
  • Eliminating the need for emulsion breaking chemicals
  • Extended time between scheduled maintenance periods
  • Elimination of ongoing labor costs to change disarmed glass fiber coalescer elements or mesh packs
  • Efficient, high-performance design for smaller assembly size

Applications/ Use

Pall’s Liquid/Liquid Coalescers are used in various applications to remove water, particulate matter, and other fluids efficiently.

Oil & Gas

  • Refinery Alkylation
  • Refinery Amine Systems
  • Refinery Caustic Treatment
  • LNG Acid Gas
  • Midstream Acid Gas
  • Liquid Fuel Treatment
  • Refinery Final Product
  • Refinery Molecular Sieve Drier
  • Refinery React/Catalyst Protect
  • Upstream Condensate
  • Refinery Condensate Dewatering
  • Midstream Mol-sieve Dehydration
  • LNG Stabilization Column
  • Midstream Gas Pipeline Compressors
  • Midstream Glycol Filtration
  • Midstream Merc Rem Unit (MRU)
  • LNG Other
  • Midstream Black Powder

Chemicals & Polymers

  • Petrochem quench water
  • Chemical Final Product (Liquid)
  • Poly Commodity Intermediate (Fluids)
  • Poly Engraved & Special Intermediate (Fluids)
  • Ammonia Liquid/Hyd Peroxide intermediate
  • Naphtha/Propane/Propylene Feed
  • PetroChem Final Product (Liquid)
  • Chem Raw Material - Liquid
  • Chemicals Raw Material/Gas/Air
  • Petrochem Selective gas/gas separation
  • Amine/Benfield /Other Solvent loop
  • Molecular sieve protection

Power & Utilities

  • Liquid Fuel Treatment
  • Diesel Generators

Industrial Manufacturing

  • Heavy Lubrication
  • Midstream Process Water


1. What are the benefits of using Pall’s Liquid/Liquid Coalescers?

Pall’s liquid/liquid coalescer separators efficiently separate water, fluids, and particulate matter with lower separation, operation, and maintenance costs. These coalescers prevent catalyst deactivation in downstream processes, reduce corrosion problems in downstream equipment, eliminate the need for emulsion breaking chemicals, and help resolve many other issues. 

As the liquid/liquid coalescers don’t disarm, they offer extended service life and eliminate ongoing labor costs. The filters are built with a high-performance design that leads to a smaller assembly size. 


2. How do Pall’s Liquid/Liquid Coalescers work?

Pall’s liquid-liquid coalescers effectively filter using three stages. 

  • By removing solids with a cartridge filter, the coalescer preconditions the fluid for optimum coalescer performance.
  • A high-performance coalescer medium captures the droplets that are to be separated from the bulk liquid and moves them through a coalescer media with progressively larger pores where they are coalesced to form larger droplets. 
  • These droplets are released from the media. The phases are separated by either coalescing filter separators or by gravity in the settling zone.


3. Why are Pall’s Liquid/Liquid Coalescers less prone to disarming in the presence of surfactants?

Pall’s specially engineered coalescing media options do not allow surfactants to coat the surface of the media fibers to prevent disarming. This is in contrast to glass fiber media that is used in most other competitor coalescer products and highly prone to disarming.


4. What are the applications of Pall’s Liquid/Liquid Coalescer systems?

Pall’s Liquid/Liquid Coalescers are used in various applications that demand efficient removal of particulate contamination and water. Some of the applications involve: 

  • Fuel systems and fuel delivery systems in aircraft, helicopter, ship, submarine, military, and commercial vehicles
  • Refinery applications during alkylation, amine systems, and caustic treatments
  • Midstream water processing
  • Midstream LNG acid gas
  • Separation of oil from water, ammonia, caustic, urea, and acid streams 
  • Molecular sieve protection, midstream molecular sieve dehydration, refinery molecular sieve dryer