Slashing Sludge & Chemical Costs: How SINOKLE’s Coalescence + CDFU Process Revolutionizes High-Oil Tank Farm Drainage Treatment
In the petroleum refining process, tank farm draining is one of the most typically difficult-to-treat sources of oily wastewater. As the trend toward heavier and lower-quality crude oils intensifies, the oil content in wastewater accumulated at the bottom of tanks has skyrocketed—consistently hovering at high levels from several thousands to tens of thousands of mg/L, and even reaching up to 100,000 mg/L—accompanied by high concentrations of COD and suspended solids (SS).
Traditional sedimentation tanks or chemical-dosing dissolved air flotation (DAF) processes often fall into a vicious cycle of "high energy consumption, massive sludge generation, and incomplete oil removal," and can even pose safety hazards due to water seal failures.
Faced with this industry dilemma, how can low-cost, low-risk, and high-efficiency reclamation be achieved? Shenzhen Clear Science & Technology Co., Ltd (SINOKLE) provides a disruptive solution centered on "High-Efficiency Coalescence + Cyclone Dissolved Gas Flotation."
Core Breakthrough: From "Chemical Reliance" to "Physical Separation"
Unlike traditional processes that rely heavily on massive amounts of flocculants, this pretreatment process consists of two core units connected in series: a Coalescing Pressurized Oil Separator and a CDFU (Cyclone Dissolved Gas Flotation) unit, supplemented by necessary equalization and lifting facilities.
The specific process flow is as follows:
· Equalization and Lifting: Tank farm drainage first enters a slop oil equalization tank for flow regulation and pre-sedimentation, after which it is delivered via lifting pumps to the main treatment line.
· Primary Treatment (Coalescence Oil Removal): The wastewater enters the Coalescing Pressurized Oil Separator. Utilizing super-hydrophilic modified media (modified via atomic layer deposition technology), the interfacial energy of oil droplets is altered. This promotes the collision and coalescence of micron-sized dispersed oil into larger oil droplets, which then float up and separate. This stage primarily completes the interception of free oil and large-particle suspended solids.
· Secondary Treatment (Cyclone Flotation): The effluent from the primary treatment enters the CDFU cyclone dissolved gas flotation unit. This unit combines cyclonic centrifugal separation with micro-nano bubble flotation technologies, performing deep stripping targeted at emulsified oil and fine suspended solids to further enhance the three-phase oil-water-solid separation effect.
Compared to traditional chemical-dosing flotation or biochemical pretreatment processes, this physical combined process exhibits the following technical features:
Dimension | Technical Performance |
Separation Mechanism | Purely physical process: Zero dosing of chemicals such as demulsifiers or flocculants throughout the entire process. Relying purely on physical coalescence and buoyant separation, it avoids secondary interference to water quality caused by chemical agents. |
Treatment Efficiency | High-efficiency removal: The two-stage treatment stably controls the effluent oil content to below 10 mg/L (specifically for crude oil tank farm drainage). It also exhibits a significant synergistic removal effect on SS and COD, providing favorable influent conditions for downstream biochemical systems. |
Product Destination | Resource recovery: The separated slop oil has a low moisture content and can be directly recycled back into the crude oil system. The volume of sludge generated is extremely minimal—consisting primarily of inorganic impurities—thereby reducing the hazardous waste disposal burden. |
Operational Stability | High shock resistance: The physical separation mechanism is minimally affected by fluctuations in water temperature and pH. Coupled with an automated control system, it successfully adapts to the intermittent nature and wide water-quality fluctuations characteristic of tank farm dewatering. |
Footprint and O&M | Intensified design: Adopting a skid-mounted modular design with a high level of integration, the footprint is significantly reduced compared to traditional processes. Due to the absence of a chemical dosing system, daily operation and maintenance (O&M) are simplified, requiring minimal labor. |
Conclusion
Tailored to the characteristics of refinery tank farm drainage—namely "high oil, high COD, and difficult emulsification"—the physical combined process of "coalescence + cyclone flotation" effectively resolves the sludge disposal dilemmas and operating cost pressures brought about by traditional chemical methods. With clear process logic, this system achieves high-efficiency oil-water dissociation through step-by-step separation, holding substantial engineering application value in the field of industrial wastewater pretreatment.
