Technological Innovation in Pretreatment of Coking Acidic Wastewater: Application of CDFU Swirl Dissolved Air Flotation and Pure-Physical Three-Stage Separation Process

In the refining, chemical, and coal chemical industries, the acidic wastewater generated by coking units is widely recognized as a difficult treatment challenge due to its complex composition, high toxicity, and difficulty of treatment. Such wastewater contains not only high concentrations of sulfides, ammonia nitrogen, and phenolic compounds, but also exhibits the physical characteristics of high emulsification, high oil content, and entrained fine coke powder, posing a serious threat to the stable operation of downstream stripping units. How to achieve efficient and stable pretreatment of such wastewater and ensure long-cycle operation of the main units is a core operational pain point that enterprises urgently need to solve.

I.Limitations of Traditional Processes: Low Efficiency Coupled with Secondary Risks
For a long time, the industry has generally adopted gravity settling or ordinary cyclone plus filtration as pretreatment means, but when dealing with highly emulsified coking acidic wastewater, these traditional processes expose a series of inherent defects:
Low separation efficiency endangering main unit safety: The traditional gravity settling method relies on residence times as long as 50 to 70 hours, with minimal separation effect on emulsified oil droplets; ordinary hydrocyclones may cause secondary emulsification due to improper design. Oil and coke powder that are not effectively removed enter the stripping tower, easily causing fouling and blockage of trays and packing and instrument failure, which not only affects desulfurization and deamination efficiency but may also trigger unplanned shutdowns, causing significant economic losses.

Secondary pollution from chemical dependence:To achieve demulsification, traditional processes often require large amounts of chemicals, leading to rising operating costs and generating large amounts of oily chemical sludge (hazardous waste), which is difficult and costly to dispose of and carries environmental compliance risks.

Poor resource recovery quality, low economic benefit:The waste oil separated by traditional methods often has high water content and many impurities, with low quality, making it difficult to directly recycle, greatly reducing resource value.

Safety hazards and excessive footprint:Open or semi-open processes carry the risk of escape of toxic and harmful gases such as hydrogen sulfide and ammonia; at the same time, large multi-stage series tanks occupy huge areas, making it difficult to meet the needs of intensive upgrading and transformation of modern factories.

II. SINOKLE Technology Process: Pure-Physical Three-Stage Progressive Separation Solution
In response to the above industry pain points, Shenzhen SINOKLE Technology, relying on its self-developed core patented equipment, innovatively launched a three-stage pure-physical treatment process centered onCDFUswirl dissolved air flotation+fine filtration+KHC high-efficiency coalescing oil removeras the core. This solution requires no chemical demulsifiers throughout the process, eliminating secondary pollution at the source.

First-stage treatment:CDFUSwirl Dissolved Air Flotation (high-efficiency demulsification and primary separation)
The wastewater first enters theCDFU(swirl dissolved air flotation unit). Through the deep coupling of the swirl centrifugal field and dissolved air release technology, the device generates a large number of ultra-fine bubbles with diameters of 5 to 30 microns inside the unit. These bubbles have an extremely large specific surface area and adsorption capacity, rapidly capturing and adhering to emulsified oil droplets and fine coke powder in the water, and using the density difference to achieve efficient and rapid separation of oil, water, and solids. The hydraulic residence time is shortened to within 5 minutes, and the single-stage oil removal efficiency exceeds 90%.

Second-stage treatment: Fine Filtration (deep interception of suspended solids)
CDFUThe effluent then enters the fine filtration unit (such as a special filter media filter). Through high-precision filter media, this unit further intercepts residual tiny suspended solids and dispersed oil droplets in the water, ensuring strict control of effluent suspended solids concentration and particle size, providing reliable protection for downstream precision equipment, and is equipped with an automatic backwash function to ensure continuous and stable operation.

Third-stage treatment: KHC High-Efficiency Coalescing Oil Remover (deep purification and oil recovery)
After removing most suspended solids, the water flow enters the KHC (high-efficiency coalescing oil remover). It is filled with special super-oleophilic and hydrophobic modified coalescing material. When micron-scale oil droplets flow through the material surface, they collide, coalesce, and grow, ultimately achieving deep oil-water separation. The effluent oil content can be stably reduced to a very low level (e.g., <50 mg/L), fully meeting the strict requirements for stripping tower influent. At the same time, the recovered oil has high purity and low water content, and can be directly reused in the production process, realizing resource value.

Core Advantages of the Process:

III. Technical Value and Industry Significance

SINOKLE's pure-physical three-stage separation technology provides a revolutionary path for the treatment of coking acidic wastewater, with far-reaching value:

Ensuring production continuity and safety:By efficiently removing emulsified oil and coke powder, it eradicates the risk of coking and blockage in the stripping tower, improves the operational flexibility and cycle of the main unit, and directly reduces the huge losses caused by unplanned shutdowns.

Achieving the unity of environmental protection and economic benefits:The zero chemicals, zero hazardous waste process route greatly reduces environmental compliance risks and sludge disposal costs; at the same time, high-quality recovered oil can be directly monetized, turning environmental investment into a new profit growth point.

Driving the green and low-carbon transformation of the industry:The technical features of skid-mounted, automated, low-energy-consumption, and intensive land use highly align with the intrinsic needs of modern factories for intelligent upgrading and sustainable development, providing a solid and reliable technical support for refining, coal chemical, and other industries to move toward a high-quality, low-emission future.