Pall’s new AquaSep XS liquid/liquid coalescer system is a lower cost solution to separate emulsions versus competitive cartridge coalescers, sand beds and electrostatic precipitators (ESPs). Its cost effectiveness is due to the ability of each coalescer element to process a higher flow while still providing superior effluent quality. Up to 60% more flow per element is now achievable, resulting in significantly lower capex, smaller footprint and volume, as well as reduced weight. Outlet quality is superior to competitive offerings. See Figures 1, 2, and 3 below.
The AquaSep XS system is a multiple-stage system starting with filtration to remove particulate matter, followed by either a one-stage horizontal coalescer or two-stage integrated vertical coalescer/separator stack to separate the two liquid phases. AquaSep XS coalescers will remove free water to a level as low as 15 ppmv1 and be effective over a wide range of conditions such as inlet liquid contaminant concentration as high as 10% and interfacial tension less than 20 dynes/cm.
The AquaSep XS coalescer system is available in two different housing configurations. Both configurations begin with a filtration stage to remove solid contaminants.
Table 1: Coalescer Selection Guide
|The dispersed phase fluid is aqueous and a horizontal vessel footprint is acceptable
|AquaSep XS coalescer in a horizontal housing without separator
|The dispersed phase fluid is oil and the continuous phase fluid is aqueous
|The dispersed phase fluid is aqueous and minimal footprint is required
|AquaSep XS coalescer/separator stack in a vertical housing
AquaSep XS Coalescer— Horizontal Housing Configuration
In a horizontal housing, the liquid/liquid mixture enters the coalescing element and flows inside-to-outside, small liquid dispersed phase droplets suspended in the continuous phase come together, or coalesce, as the mixture moves through the AquaSep XS coalescer. The large coalesced droplets of the dispersed phase separate by gravity in the horizontal housing and are removed. The size of the housing is a function of the flow rate, IFT, viscosity, and specific gravity of the liquids.
AquaSep XS Coalescer/Separator Stack— Vertical Housing Configuration
The liquid/liquid mixture enters the coalescing element and flows inside-to-outside. Small liquid droplets suspended in the continuous phase come together, or coalesce, as the mixture moves through the coalescer medium.
Contaminant-free liquid and large droplets of the dispersed phase flow toward the separator located directly below the coalescer stage. The flow is outsideto- inside. The separator medium is hydrophobic preventing the aqueous phase from entering the separator. Only the non-aqueous continuous phase fluid flows through the separator. The two liquids are removed by separate drain connections.
1Performance can vary depending on application.
Not all coalescers provide a high quantitative removal of dispersed liquid contaminants and can handle emulsions with low interfacial tensions (IFTs). For example, conventional cartridge coalescers made of glass fiber media begin to lose efficiency when the IFT of the emulsion gets below 20 dyne/cm. In contrast, the new AquaSep XS coalescer from Pall is constructed of a high-efficiency, polymeric medium, making it well suited for numerous liquid/liquid separation applications with very low IFTs including:
- Removal of water from refined products with or without additive package, including gasoline, diesel, jet, and LPG
- Separation of water from hydrocarbon condensates, refinery intermediates, naphtha, propane, propylene
- Removal of water from aromatics
- Separation of oil from water
|Maximum operating temperature
|Maximum differential pressure
|3.4 bard/50 psid at 21°C/70°F
|1.0 bard/15 psid at 21°C/70°F
Comparative PerformanceNOTE:Comparison tests were performed in a Pall laboratory with a limited number of 20 inch elements that were purchased through standard commercial channels. Lab results may not be identical to test results with actual process fluid under field conditions.
|Availability of a High Performance Integrated Stack Design-Coalescer and Separator