CDFU Cyclonic Flotation plus KHC Coalescing Technology Solves the Coking Wastewater Challenge
The highly emulsified, highly acidic wastewater produced by the coking process in refineries is complex and very challenging. Its main characteristics are:
high content of fine coke powder;
high oil content with fine droplets and severe emulsification;
high concentrations of sulphides, ammonia nitrogen and phenols;
large fluctuations in composition and concentration.
If such wastewater enters the stripper directly it easily clogs equipment, reducing stripping efficiency and liquid ammonia quality and even causing unplanned shutdowns with major economic losses. Conventional chemical treatment consumes large amounts of reagent, generates large volumes of scum and oily sludge, performs inconsistently and carries a risk of secondary pollution.
To solve these problems, an innovative treatment system based on purely physical demulsification and separation has been successfully developed. The core process is CDFU cyclonic dissolved air flotation plus a fine filter plus the KHC high-efficiency coalescing oil separator. The flow is as follows:
Process flow diagram of the refinery acidic wastewater treatment
1. Coarse filtration: removal of large particulate impurities.
2. CDFU cyclonic dissolved air flotation: cyclonic action and dissolved gas efficiently separate suspended solids and emulsified oil.
3. Fine filtration: further retention of solid particles and residual emulsified oil.
4. KHC high-efficiency coalescing oil removal: deep purification that thoroughly removes fine oil droplets and residual suspended solids, giving clear effluent with an oil removal rate above 99%.
Compared with conventional chemical methods, the new process has clear advantages:
Zero chemicals: no heavy reagent consumption and no scum or oily sludge, rooting out secondary pollution.
Stable, efficient physical demulsification: powerful separation of emulsified oil and suspended solids.
High-quality waste oil recovery: the recovered oil has low water content and can be re-refined directly, delivering resource recovery and economic benefit.
Safe and clean: fully automatic, sealed operation under pressure with no environmental risk.
Economical and compact: small footprint and low operating cost.
Practical results:
A petrochemical company in Luoyang has applied this system successfully. The inlet wastewater oil content was as high as 15% (150,000 ppm), and the treated effluent oil content stayed below 50 ppm on average, with oil removal above 99%, completely solving its acidic wastewater problem.
The successful application of this process provides an efficient solution for highly emulsified coking acidic wastewater and marks a major breakthrough in China coking wastewater treatment technology, strongly supporting the sustainable and green development of petrochemical companies.
