High-Efficiency Coalescing Oil Remover + CDFU: Treating High-Oil Desalter Effluent

Desalter effluent is difficult to treat because of its water quality: high and fluctuating oil content, high resin and asphaltene content, severe emulsification and a small oil-water density difference. For feed like this, conventional processes such as gravity settling, cyclonic de-oiling and membrane filtration run at high cost with poor results, and oil levels at the inlet of the wastewater plant frequently exceed the limit.

1. Solution overview: patented technology + purely physical separation

SINOKLE has built its overall desalter wastewater solution around the patented combination of the high-efficiency coalescing oil remover and CDFU (cyclonic dissolved-air flotation), a fully physical separation route. The equipment runs steadily, treats water effectively and occupies a small footprint; it operates fully enclosed, pressurised and automatically, and is safe and environmentally friendly. The technology is internationally advanced and can be installed and commissioned online without shutting down the desalter unit.

2. Option 1: high-oil combined process

For desalter effluent with high oil content and severe emulsification, the process combines the high-efficiency coalescing oil remover+CDFU cyclonic dissolved-air flotation into one train. The coalescing internals make fine oil droplets grow and separate first, and CDFU cyclonic dissolved-air flotation then captures the remaining emulsified oil; each stage does its own job and together they handle high-load, heavily emulsified feed.

3. Option 2: two-stage CDFU process

For feed with lower oil content, two stages of CDFU cyclonic dissolved-air flotation are used. With 0.5%-5% oil in the feed, effluent oil is below 50mg/L and oil removal exceeds 90%, while the separated crude has a water cut below 1%.

4. Why is this solution better?

First, purely physical separation means no chemicals, no secondary pollution and no extra burden on downstream biological treatment. Second, fully enclosed pressurised automatic operation is safe, environmentally friendly, needs little manpower and runs steadily. Third, the footprint is small, skid-mounted deployment is flexible, and online installation without shutdown keeps retrofit downtime low. The biggest gain is economic: Option 2 recovers crude with a water cut below 1%, which is high-quality crude, so the wastewater treatment investment returns real crude oil.

For refiners, desalter effluent is no longer an unsolvable problem. Matching the two options to the feed oil content delivers compliance, cost savings and crude recovery at the same time.

Looking inside the Option 1 process chain, the high-efficiency coalescing oil remover performs coarse separation, using coalescing internals to grow fine droplets and accelerate their rise, greatly reducing the oil load entering the flotation stage; CDFU cyclonic dissolved-air flotation performs fine separation, capturing residual emulsified oil through cyclonic centrifugation and microbubble attachment. Working together, the two stages protect downstream equipment and keep effluent stable.

In operation, purely physical separation means no chemicals, no dosing system and no chemical inventory costs; enclosed pressurised automatic operation needs little intervention; and the small, highly skid-mounted package is easy to deploy. On the benefit side, Option 2 achieves effluent below 50mg/L with over 90% oil removal while recovering high-quality crude with a water cut below 1%, creating a virtuous circle between environmental spending and crude recovery.

High-oil desalter effluent has never been an unsolvable multiple-choice question. With patented technology, a purely physical route and two clearly defined options, SINOKLE turns the problem into an executable engineering answer. Refiners should rethink desalter wastewater treatment starting from this solution.

To discuss how the solution can be implemented, please talk to the SINOKLE technical team.

The solution also suits wastewater reuse and upgrading projects in refineries, leaving room for future expansion.

Only when the environmental and economic accounts are added together does the value of the solution really show.

Operating data match the process design, and selection, design, implementation and maintenance all follow a documented basis - that is the confidence behind a mature technology route.