Do you struggle with the efficiency of your fish oil winterization process? Stearin recovery is a constant headache for many manufacturers, particularly when you’re striving for higher yields and better quality.

Good news: a filter machine can be your game-changer for stearin recovery. With the right setup, you can maximize recovery rates while maintaining optimal winterization performance.

Intrigued? Stick around. I’ll walk you through this transformative approach to fish oil winterization processing.

Why to Winterize Fish Oil?

Winterization isn’t just about making fish oil looks better; it’s a crucial phase to remove unwanted fatty acids, aldehydes, and ketones.

The compositional profile of fish oil can vary significantly depending on the fish species, leading to differences in the content of saturated fatty acids as well as the distribution of fatty acids in the glyceride structure. Consequently, these variations translate into noticeable differences in the physical properties of fish oil, both at room and low temperatures.

Deep-sea fish oil, after undergoing critical refining processes like alkali refining, degumming, decolorization, and deodorization, remains enriched with specific stearin and saturated fatty acid esters with higher melting points. Such impurities also compromise the oil’s digestibility, influence its taste negatively, and reduce both its nutritional worth and its application value.

To elevate the standard of refined fish oil and maintain its superior quality, it becomes imperative to separate the stearin meticulously. The most prevalent and efficient method for this separation is the winterization (dry fractionation) technique.

While winterization is a mandated process strictly for edible fish oils to pass rigorous freezing tests, its application is not confined solely to this category. Expanding the utilization of winterization techniques to other types of oil and fats is an instrumental strategy to enhance overall product quality.

The significance of the winterization process lies in its ability to achieve two primary objectives:

1. Lowering the Freezing Point: The process reduces the freezing point of fish oil, thereby enhancing its physical characteristics and stability at lower temperatures.
2. Improving Fatty Acid Composition: More critically, winterization facilitates the fractional crystallization of the fish oil, which not only segregates saturated fatty acids but also concentrates essential polyunsaturated fatty acids such as EPA and DHA in the liquid fraction.

What’s the Deal with Stearin Recovery?

Stearin is a valuable byproduct that can be repurposed for a variety of applications. However, the conventional processes for stearin recovery can be cumbersome, time-consuming, and wasteful. Don’t you wish there was a better way?

Filtration & Separation of Stearin from Fish Oil

In the fish oil winterization process, the utilization of specialized high-efficiency, energy-saving filtration equipment is indispensable for achieving superior separation outcomes.

Engineered specifically for the fish oil winterization and fractional crystallization process, this separation equipment is equipped with advanced features designed to effectively filter and separate crystallized stearins from the liquid oil fraction.

The filtration equipment boasts a robust and stable structural design, augmented by a highly secure sealing performance within the filtration assembly. Such attributes make it exceptionally suited for large-scale industrial continuous oil refining and separation processes.

Dewaxing filters commonly used are membrane filter press, plate and frame filter, thermal melt winterization filter, horizontal leaf filter, etc., although they can meet the requirements of winterization process, but the removed stearin ester oil content, refining rate, manual operation and filter cloth loss vary greatly.

Membrane Press Filter:

The Membrane Press Filter is an advanced filtration system incorporating an elastic membrane between the filter plate and the filter cloth. During operation, once the feed material has been fully introduced, high-pressure fluid or gas is injected into the membrane plate. This action causes the membrane to expand, exerting additional pressure on the filter cake for a secondary pressing operation, thus achieving deep dewatering.

This state-of-the-art equipment is particularly well-suited for applications requiring low moisture content in the filter cake post-filtration, such as viscous materials, municipal sludge, chemical sludge, and coal slurry. With its robust design and precision engineering, the Membrane Press Filter offers an optimal solution for users with high moisture reduction requirements, setting a new standard in efficient and effective filtration.

Hot Melt Type Filter:

As an integral piece of equipment designed for the fractionation of waxes and fats from both plant and animal-based oils. This highly specialized device is employed in winterization processes to efficiently separate oils and waxes of differing melting points, as well as liquid oils from stearin.

Applicable to a wide array of oils including deep-sea fish oil, rice bran oil, corn oil, sunflower oil, cottonseed oil, tea seed oil, sesame oil, and pork fat, this equipment is engineered for both de-waxing and de-greasing operations. Its versatility and efficacy make it a staple in the modern refining processes of various oils, meeting the industry’s stringent quality and performance requirements.

Plate Frame Filter Press

The Plate Frame Filter Press is a highly engineered filtration equipment designed for intermittent pressure filtration operations. The system is composed of four key components: the frame, filter plates, a compression system available in three variants—manual, mechanical, and hydraulic—and an electrical control cabinet.

The frame section serves as the structural foundation supporting both the compression device and the filter plates. It is assembled from a base, a compression plate, a thrust plate, and a main beam. Filter plates are strategically positioned on the main beam between the compression and thrust plates, with filter cloths sandwiched in between.

This versatile filtration solution is well-suited for various industries, including chemical, pharmaceutical, environmental, mining, construction, and railways. It excels in tasks requiring solid-liquid separation, sludge dewatering, and wastewater filtration.

What Makes a Filter Machine Special?

Comparative Analysis of Membrane Press Filter, Plate Frame Filter Press, and Hot-Melted Type Filter for Solid-Liquid Separation Processes

Structural Design:

• Membrane Press Filter: This filter is engineered with a flexible membrane, membrane plates, and filter cloths that together form multiple filtration chambers. Liquid and solid components are efficiently separated through the membrane layer.
• Plate Frame Filter Press: Consisting of filter frames and filter plates, this device also features multiple filtration chambers. Filter cloths are held between filter frames and plates, which support the solids, while the filtrate flows through the cloth.

Operational Modality:

• Membrane Press Filter: Typically features a high degree of automation, offering automatic control and monitoring through an advanced control system.
• Plate Frame Filter Press: Usually requires manual operation and offers a relatively simpler operational approach.

Control Flexibility:

• Membrane Press Filter: Exhibits high operational flexibility by allowing adjustments to the flow rate and pressure during the filtration and squeezing stages.
• Plate Frame Filter Press: Lacks the capability to adjust pressure and flow rate during the filtration process, making its operation relatively static.

Filtration Efficiency:

• Membrane Press Filter: Due to its membrane functionality, it offers complete separation of solids and liquids, usually rendering superior filtration results.
• Plate Frame Filter Press: May experience some level of permeation between solids and liquids during filtration, resulting in suboptimal filtration efficiency.

Applicability:

• Membrane Press Filter: Ideal for materials with fine, small-sized solid particles and is especially well-suited for filtering corrosive or high-temperature substances.
• Plate Frame Filter Press: Best for materials with larger particles and higher solid content, and is particularly effective in industrial wastewater treatment and other solid-liquid separation applications.

Hot-Melted Type Filter: The Game Changer

This type of filter combines the advantages of the Plate Frame Filter Press while eliminating its drawbacks. The primary benefit is its ability to meet the continuous refining needs of 30-50 tons/day of oils and fats with just two alternating devices.

There is no need to dismantle the filter frames and cloths for cleaning. Instead, hot water is channeled through the coils within the filter frame, melting the crystallized esters for easy removal. This design minimizes equipment wear caused by multiple disassemblies, significantly reduces labor intensity, increases work efficiency, prolongs equipment lifespan, conserves production resources, lowers production costs, and enhances economic returns for the user.

Pros and Cons of Membrane Type Filter Press

The Membrane Filter Press represents a sophisticated filtration system, featuring a core component known as the membrane filter plate. Constructed from polypropylene material, the plate offers several advantages, including low weight, minimal thermal loss, high tensile strength, superior mechanical integrity, corrosion resistance, and resistance to deformation. The strategically designed membrane and corner feed structure augment the filter press’s functionalities.

Operational Workflow:

Upon filling the filter chambers with well-crystallized fish oil, the material input is halted. Initially, low-pressure compressed air (with 0.2 MPa) passes through the membrane filter plate to pre-compress the wax cake, thereby equalizing its pore channels and enhancing its ventilation properties. Subsequently, the compressed air pressure is increased to 0.6 MPa. This higher pressure, executed through a high-pressure airbag, is effective in thoroughly expelling the oil from the wax cake, resulting in a low oil content and well-formed cake.

Advantages:

1. Efficiency: When the system is automated, the advanced drum membrane pressing feature eliminates the need for secondary pressing, thereby enhancing operational efficiency.
2. Cost-effectiveness: The technology significantly reduces the oil content in the wax cake, increasing refining rates and offering cost savings.
3. High Mechanical Strength: The membrane filter plate is highly durable and resistant to wear and tear, ensuring long-term service.
4. Low Heat Loss: The polypropylene material of the plate maintains minimal thermal loss, conserving energy.
5. Corrosion Resistance: The material is inherently resistant to most chemicals, providing an added layer of durability.

Limitations:

While the membrane filter press is replete with advantages, it is important to note the following:

1. Initial Investment: The technology, particularly automated versions, may require a substantial upfront capital investment.
2. Operational Complexity: The need for precise control over compressed air pressure may require specialized training for operators.
3. Exposure to Air: The stearin in the the filter plate and transfer route to tank will be exposed to air and cause a certain ratio of oxidation of stearin.

Pros and Cons of Thermal Melting Type Filter

The Hot-Melt Dewaxing Filter facilitates the intricate process of separating crystallized wax or stearin from fish oil. Initially, the crude deodorized oil undergoes a freezing crystallization and cultivation stage. Utilizing the principle of liquid-level difference, the material flows spontaneously into the filter’s wax-separating chamber at a low-pressure threshold of <0.2 MPa.

The separation is performed through a filter cloth that effectively segregates the liquid oil from the crystallized wax or stearin. The liquid oil permeates through the cloth and is channeled into an oil collection trough, from which it is subsequently pumped into a colorant tank. In contrast, the wax or stearin remains in a solid state and is thus confined within the filter chamber due to its inability to penetrate the filter cloth.

After a predetermined filtration duration—evident by the decreasing flow rate of the liquid oil—the input is halted. All the oil and wax release valves are then closed. At this point, a heating source circulates through coils within the filter chamber, melting the retained crystallized wax or stearin. Once liquefied, the release valve for the wax is opened and the liquid wax is collected and pumped into a tank for industrial re-utilization.

Closed-Loop Oil Circulation and Stearin Recovery System

While this system is featured with complete closed stearin discharging and cleaning process, which minimize air contact, ensuring optimal flow and recovery of stearin, it is important to note that 100% isolation from air contact may not be achievable. Small quantities of oil and stearin may come into contact with air on the cloth. However, the equipment is engineered to significantly limit the majority of air exposure to the material, maintaining the quality and integrity of the material being recovered.

Performance Comparison: Automatic Membrane Filter Press vs. Hot Melt Type Filter

Filtration Rate:

In traditional hot melt-type filters, filtration speed is inversely proportional to filtration time. While initial filtration is rapid, there’s a linear relationship between filtration volume and time. As time progresses, the wax cake thickens, increasing the filtration resistance and subsequently decreasing both the filtration speed and volume. The Automatic Membrane Filter Press circumvents this issue with its pneumatic membrane filter plate. After rapid filtration, it shifts to an auxiliary program to reduce the oil content in the wax cake via pneumatic squeezing, substantially shortening the filtration cycle.

Oil Content in Wax Cake and Time-Efficiency:

The hot melt type filter relies on extending the feed time and blowing compressed air to reduce oil content, which slows down the filtration process and consumes compressed air. In contrast, the Automatic Membrane Filter Press relies on airbag pressure to reduce the oil content in the wax cake. With the increase in squeezing pressure, oil content can be reduced to as low as 40%, significantly boosting economic efficiency.

Quality of Winterized Oil:

The large plate frame area in hot melt-type filters results in dead zones. Compressed air is blown in from the top of the plate frame, which could potentially dislodge some insoluble matter. The Automatic Membrane Filter Press uses compressed air within its airbag to expel the oil from the wax cake, yielding clear and transparent oil.

Automation Level:

Hot melt-type filters are mainly operated manually. Automatic Membrane Filter Press, the feed pump automatically adjusts the input pressure based on the filter press pressure, and the plate vibration for cake discharge is also automated, reducing labor intensity.

Air Isolation:

Hot melt-type filters can isolate air to a greater extent, reducing the extent of oil and stearin oxidation.

In summary, while both systems have their merits, the Automatic Membrane Filter Press offers a higher degree of automation, greater economic efficiency, and superior quality control in winterized oil production. The Hot Melt Type Filter, although effective in isolating air, faces challenges in terms of filtration speed, labor intensity, and oil content management. Therefore, choosing between the two systems would depend on your specific operational priorities and requirements.

Here’s where things get interesting. A filter press machine is highly efficient in separating liquid from solid components. With the correct membrane and pressure settings, it can work wonders in stearin recovery.

Any Customization Options?

You’re in the driver’s seat! The filter press machine can be tailored to suit your specific needs. Different membrane types, plate sizes, and pressure settings—it’s like a made-to-order suit for your factory.

Determine Production Requirements

Prior to customizing a membrane filter press, it is imperative to establish specific parameters related to the production needs. This includes understanding the material characteristics, particle size, moisture content, and production volume. Additionally, key parameters such as the viscosity and specific gravity of the substances to be separated must be considered to lay the foundation for customization.

Select Suitable Filter Plate Material

The choice of filter plate material has a significant impact on the longevity and filtration efficiency of the device. Different materials like polypropylene, stainless steel, and cast iron serve various applications depending on the solid content, raw material properties, and filtration objectives. Consideration should also be given to the material’s corrosion and abrasion resistance.

Opt for the Correct Filtration Media

Choosing the right filtration media is a critical aspect of customizing a filter press. The chosen media must be compatible with the material properties and should also be evaluated in terms of filtration speed and processing volume. Decisions should be made based on the scale of the production line and the cost factors associated with the filtration media.

Specify Processing Parameters

When customizing a membrane filter press, it is crucial to set appropriate processing parameters aligned with product requirements. For a filter press, parameters such as pressure, filtration time, and discharge methods not only influence the production efficiency but also have a direct impact on the quality of the output.

Incorporate Safety Considerations in Design

Safety considerations should be an integral part of customizing a filter press. This includes planning the workshop layout and training operators. Special industrial application requirements may dictate specific design considerations. Both the status of the operators and the plant machinery should be taken into account during equipment selection and customization.

Consider Maintenance and Cleaning

The design should facilitate easy maintenance and cleaning in real-world operation. Moreover, appropriate cleaning methods must be established based on the material characteristics. This requires planning for the necessary cleaning and maintenance activities as well as the associated training procedures.

Conclusion

Revamping your stearin recovery process is not just about improving efficiency—it’s about upping your game in the highly competitive fish oil market. The filter press machine can be a cornerstone in achieving this goal. Your yield, quality, and bottom line for optimal fish oil winterization.

If you need any solution for oil and lipids filtration, please send us your process requirements for detail discussion.

Reference sites:

https://goedomega3.com/

https://en.wikipedia.org/wiki/Filter_press

https://www.sciencedirect.com/science/article/abs/pii/B9781893997820500086

https://lipidlibrary.aocs.org/edible-oil-processing/dry-fractionation