Caustic Treatment | Spent Caustic Filtration - Refineries

Refinery Requirements for Caustic Treatment

Caustic treatment 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.

Caustic Carryover

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.

Refinery Needs From Caustic Treatment

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

Refinery Production Challenge / Pall Solution for Caustic Treatment

Challenge	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® EL 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. This is where better caustic filtration options are critical. KO pots, mesh pads, cyclonic devices and conventional filter-separators may not effectively remove the stable spent caustic emulsion. This is where better caustic filtration options are critical. High efficiency PhaseSep® EL 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 wide range of filter elements for caustic treatment is available to reduce suspended solids to improve the efficiency and life of the liquid/liquid coalescer.

Challenge

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® EL 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. This is where better caustic filtration options are critical.

KO pots, mesh pads, cyclonic devices and conventional filter-separators may not effectively remove the stable spent caustic emulsion. This is where better caustic filtration options are critical.
High efficiency PhaseSep® EL 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 wide range of filter elements for caustic treatment is available to reduce suspended solids to improve the efficiency and life of the liquid/liquid coalescer.

Caustic Treatment Process Flow Diagram

Key Application in Caustic Treatment/Filter Recommendations (other applications not shown)

Diagram number	Application	Pall Product	Customer Benefits
1	Prefiltration prior to liquid/liquid coalescer	Nylon or polyphenylene sulfide (PPS) Profile® filter	Low operating costs by improving the life of the liquid/liquid coalescer
2	Spent caustic treatment	PhaseSep® EL in horizontal configuration	Assured production and quality by meeting caustic filtration specifications for haze and sodium levels Prevents downstream unit downtime from caustic contamination of catalytic processes

Diagram number

Application

Pall Product

Customer Benefits

Prefiltration prior to liquid/liquid coalescer

Nylon or polyphenylene sulfide (PPS)

Profile® filter

Low operating costs by improving the life of the liquid/liquid coalescer

Spent caustic treatment

PhaseSep® EL in horizontal configuration

Assured production and quality by meeting caustic filtration specifications for haze and sodium levels

Prevents downstream unit downtime from caustic contamination of catalytic processes

For more information on improving the efficiency of your processes, contact our team of filtration experts.

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Refinery Applications - Caustic Treating.pdf

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