Caustic treating is used to upgrade a wide range of liquid fractions from LPG to diesel fuels and heating oils. As the caustic solution (and often a catalyst) mixes with the hydrocarbon feed it either extracts or sweetens mercaptans, depending on the process used.
However, the combination of the hydrocarbon and mercaptan rich caustic also forms a very stable emulsion that is difficult to separate, causing significant quantities of caustic carryover in the product. This results in off-specification products due to haze or elevated sodium concentration and loss of caustic. In many cases the entrained caustic is fed to processes where sodium is a poison to the catalyst.
Because the emulsion is so stable, knock-out drums, sand filters and packed vessels are not able to efficiently separate the caustic emulsion from the hydrocarbon streams.
- Achieve oil production quotas via reliable treatment of mercaptans and hydrogen sulfide
- Meet product quality specifications for haze and sodium levels
- Protect and extend run life of downstream catalytic process units
Production Challenge / Pall Solution
Meet product specifications
Improve refinery productivity and product specifications by removal of spent caustic carryover via effective liquids and solids removal downstream of the extractor.
- KO pots, sand beds, water washes, and salt towers may not effectively remove the stable spent caustic emulsion.
- High efficiency PhaseSep® liquid/liquid coalescers reliably meet ‘clear and bright’ product specification and sodium levels downstream.
Protect downstream catalytic process units
Improve protection of downstream process units by removal of spent caustic carryover via effective liquids and solids removal downstream of the extractor.
- KO pots, mesh pads, cyclonic devices and conventional filter-separators may not effectively remove the stable spent caustic emulsion.
- High efficiency PhaseSep liquid/liquid coalescers reliably meet ‘clear and bright’ product specification and sodium levels downstream.
- Solid particle contaminants in the spent caustic may not be adequately removed by filters that exhibit unloading, media migration, channeling or poor sealing.
- A range of filter elements is available to reduce suspended solids to improve the efficiency and life of the liquid/liquid coalescer.
refinery caustic treatment systems
Meet product quality specifications, and extend the run life of downstream catalytic process units.
Use of caustic treating to remove acids, hydrogen sulfide and/or mercaptans from hydrocarbon intermediate and final product streams generates spent caustic waste. This high pH wastewater is toxic and highly odorous, and can carry over into the product resulting in off-specifications due to haze or elevated sodium concentration. The spent caustic forms a stable emulsion that s difficult to remove using knock-out drums, sand beds, electrostatic precipitators (ESPs), water washes or salt towers. Pall offers a leading edge prefilter and liquid/liquid coalescer solution for refinery caustic treatment systems to achieve production quotas, meet product quality specifications, and extend the run life of downstream catalytic process units.
For prefiltration prior to the liquid/liquid coalescer, Nylon Profile® filters or Ultipleat® High Flow filters deliver efficient removal of solids.
Nylon Profile® filters are constructed from Nylon. In some cored configurations, the Nylon core may also contain glass fibers for reinforcement. Different configurations such as Profile coreless or Profile II elements are available to suit your flow requirements. The elements contain an absolute-rated downstream section, and a continuously graded pore size upstream section, which increases service life. Since the fibers in Profile filters are continuous and are “bonded” by intertwining during the manufacturing process, the filters show no media migration and have fixed pore construction that provides consistent downstream fluid quality.
The Ultipleat® High Flow filter is a large diameter, coreless, single open ended, pleated cartridge with an inside-to-outside flow pattern. The filter's unique crescent-shaped pleat geometry, combined with its large 152.4 mm (6 inch) diameter and proprietary range of available Pall filter media, allows the use of significantly fewer filters and smaller housings for high flow rate applications.
b) Liquid/Liquid Coalescing
High efficiency PhaseSep liquid/liquid coalescers reliably remove spcnt caustic / high pH water to meet ‘clear and bright’ product specification and sodium levels downstream. These coalescers remove caustic carryover from hydrocarbon product to assure the highest quality and prevent downstream unit downtime from caustic contamination of catalytic processes.
Pall's spent caustic filter and coalescer systems reliably treat high pH finsl products and intermediates to help meet daily production quotas and downstream process protection needs. For more information, click here to see purchase information or talk to a Pall expert.
Don’t take our word for it. Just ask the thousands of refinery engineers around the world why Pall is their supplier of choice for filtration and separations solutions. Let them tell you how our extended filter life and simple maintenance protocols save them time that can be spent on value-add process improvements.
Ask them about the reliability and consistent output from the Pall systems installed in their critical processes. You don’t want to spend time worrying about your filters and coalescers, and we don’t want you to either.
Contact Pall today and let us put our 50+ years of experience to work for you.
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