All You Need to Know About SPDU for Fish Oil Concentration

What is Short Path Molecular Distillation?

Short path distillation unit(SPDU) is a separation technique that capitalizes on the differences in average free path lengths of molecules among various components. The average free path is directly proportional to the distillation temperature (thermodynamic temperature) and inversely proportional to both the distillation pressure and the square of the average molecular diameter.

Under identical temperature and pressure conditions, smaller molecules, such as ethyl esters of fatty acids, possess a smaller average diameter, leading to a greater molecular free path. This property allows them to more readily “evaporate” from the heated liquid surface and subsequently be captured by the condenser, resulting in their classification as the “light phase”. Conversely, larger molecules, such as EPA (eicosapentaenoic acid) and DHA (docosahexaenoic acid) ethyl esters, tend to form the “heavy phase.”

The multi-stage molecular distillation process facilitates the continuous enrichment of EPA and DHA by systematically increasing the distillation temperature for each stage. This approach allows for distillation at lower temperatures, thus enhancing the concentration of n-3 polyunsaturated fatty acids (PUFAs) and improving product yields. Furthermore, molecular distillation can effectively adjust the mass fraction ratios of EPA and DHA within high n-3 PUFA ethyl ester fish oils.

This refined methodology is particularly beneficial for producing high-quality fish oil concentrates, optimizing both yield and component ratios for targeted applications in pharmaceuticals and nutrition.

How SPDU Benefits in Fish Oil Processing

Multi-stages Short Path Distillation (SPDU) is a highly efficient separation technology, ideal for processing fish oil, particularly in concentrating Omega-3 fatty acids. Its unique characteristics make it an essential tool for improving product quality while maintaining the integrity of sensitive compounds.

The key benefits of using SPDU in fish oil processing are:

1. Low Operating Temperature

SPDU operates at significantly lower temperatures than traditional vacuum distillation, often well below the boiling points of the separated compounds. This is achieved by maintaining an high vacuum (unloaded system gauge pressure ≤- 0.1 Pa). The short heating time, measured in seconds, helps prevent thermal degradation, making the closed circuit system suitable for heat-sensitive substances such as fish oil rich in Omega-3 fatty acids, which are prone to oxidation and thermal breakdown.

2. Efficient Removal of Impurities

SPDU is effective in removing both low-molecular-weight substances (such as odors) and high-molecular-weight substances (such as pigments). This dual capability ensures that impurities are efficiently eliminated, resulting in a higher-purity fish oil product. The process enhances the removal of undesirable compounds while concentrating the beneficial EPA and DHA components in the fish oil.

3. Physical Separation Process

The SPDU system utilizes a purely physical separation process, which protects the integrity of the separated compounds. This is particularly important for natural extracts like fish oil, where preserving the original qualities of Omega-3 fatty acids is critical. The absence of chemical reactions during separation ensures that the fish oil remains uncontaminated and retains its natural properties.

4. High Separation Efficiency

SPDU provides higher separation efficiency than traditional distillation or conventional thin-film evaporators. The system’s ability to achieve precise sequential molecular separation allows for a high degree of refinement, ensuring superior concentration of Omega-3 fatty acids. The level of separation achieved by SPDU is particularly valuable in producing pharmaceutical-grade and ultra-high purity fish oil omega-3 API ingredients, where both purity and concentration are key quality factors.

By leveraging these advantages, SPDU technology offers fish oil processors a reliable, efficient, and effective means of improving product quality while ensuring the safety and integrity of sensitive compounds.

How SPDU Outstands the Omega-3 Concentration

The process of refining fish oil, especially for enriching Omega-3 fatty acids (EPA and DHA), involves several critical steps. The use of SPDU plays a vital role in separating not only the fatty acids but also removing impurities such as oxidized materials, environmental contaminants, and other unwanted components.

Industrial multi-stage molecular distillation equipment for fish oil concentration is a specialized type of distillation system that is used to concentrate fish oil by removing impurities and unwanted compounds. The process involves heating and evaporating the fish oil under vacuum to separate the various components based on their boiling points.

The multi-stage molecular distillation system consists of a series of interconnected distillation columns or stages, each of which is equipped with its own heating and cooling systems. The fish oil is fed into the first stage, where it is heated and vaporized under a vacuum. The vapor is then condensed and collected in a separate chamber, leaving behind the heavier phase and unwanted compounds. This process is repeated in multi subsequent stages, resulting in a highly concentrated and purified fish oil PUFA product.

Here’s the detailed breakdown based on the most commonly known of process steps before and after SPDU.

1. Raw Material Inspection:

Each batch of raw fish oil is sourced from qualified manufacturers with production credentials. The raw material purchaser and the company’s laboratory conduct sensory and physicochemical tests. Only after meeting the required standards is the raw material accepted. Each batch is clearly labeled and stored in designated areas.

2. Crude Oil Pretreatment:

Crude fish oil contains water, impurities, colloids, and fish proteins, leading to a high acid value, dark color, and a strong fishy odor. Pretreatment is essential to remove these elements and achieve a certain quality standard before further processing.

The main pretreatment methods include:

• Alkali Refining for Deacidification: Using alkali to neutralize free fatty acids.

• Bleaching with Clay: Utilizing bleaching agents to remove color pigments and other impurities.

3. Esterification:

The pretreated crude fish oil, anhydrous ethanol, and sodium hydroxide (NaOH) as a catalyst are added to the esterification reactor in proportion. The mixture is heated to initiate the esterification reaction. After the reaction, a small amount of water is added to promote clear phase separation.

• Top Layer (Ethyl Esters of Fish Oil and Ethanol): This is the desired product layer.

• Bottom Layer (Glycerol and other Mixture): Byproducts and unwanted components.

4. Ethanol Removal:

Once transesterification is complete, the excess ethanol is evaporated, condensed, and recovered for reuse.

5. Decolorization:

The ethyl ester layer is injected into the decolorization reactor, where vacuum conditions remove moisture. Then a certain amount of bleaching earth is added to remove residual pigments, oxidized materials, and impurities through adsorption.

6. Molecular Distillation:

This is one of the most crucial steps in the purification process.

• Lighter Fractions (e.g., volatile impurities and shorter chain fatty acids): These are removed.

• Heavier Fractions (e.g., triglycerides, pollutants): These are separated from the ethyl esters of EPA and DHA.

By controlling temperature and pressure, short-path molecular distillation could effectively purify the omega-3 ethyl esters and remove unwanted components like oxidized byproducts and environmental contaminants.

7. Urea Inclusion and Separation:

A mixture of fish oil ethyl esters, 95% ethanol, and urea is combined. Urea selectively adsorbs the saturated fatty acid ethyl esters from the fish oil, while unsaturated fatty acid ethyl esters (EPA and DHA) remain in the ethanol. The mixture is then separated into two phases:

• Urea-Saturated Phase: Contains saturated fatty acid ethyl esters.

• Ethanol Phase: Contains unsaturated fatty acid ethyl esters.

The ethanol phase undergoes further vacuum separation, and the ethyl esters of fish oil are sent for additional short path molecular distillation processing.

8. Winterization and Filtration:

After urea inclusion, the ethyl esters are transferred to a crystallization reactor where the mixture is cooled to promote the crystallization of saturated fatty acids into solid form. The solidified fats are filtered out, resulting in various ratios of unsaturated ethyl esters (EPA/DHA).

9. Polishing and Refining Filtration:

The filtered fish oil is mixed with activated carbon. Activated carbon helps in the adsorption of heavy metals and further decolorizes the oil, ensuring the highest purity of omega-3 ethyl esters.

10. Deodorization:

The semi-finished fish oil is heated in a deodorization tower to an appropriate temperature. Superheated steam at a certain pressure is introduced, which helps in stripping off any remaining volatile compounds responsible for the fishy odor. After deodorization, the oil is cooled to the desired temperature, completing the process.

This comprehensive process allows for the production of high-quality, refined fish oil enriched with Omega-3 fatty acids, ensuring the removal of unwanted components such as water, saturated fats, free fatty acids, color bodies, and other impurities.

What Makes Up a Multi-Stage SPDU Units

The multi-stage SPDU system is specially engineered and configured to handle thermally sensitive, viscous, and high-boiling-point materials that conventional distillation methods cannot efficiently process. To acquire the performance include minimal pressure drop, high vacuum capability, high heat transfer coefficient, and a short evaporation time, ensuring the material’s integrity throughout the distillation process.

The system comprises six main subsystems:

1. Molecular Distillation System
2. Heat Transfer Oil Heating System
3. Chilled Water&Recirculating Water Condensation System
4. Vacuum Pumping System
5. Material transfer and storage system
6. Digital PLC control systems

Each subsystem plays a crucial role in ensuring efficient continuous operation, as detailed below:

1. Molecular Distillation System

The molecular distillation system is the core of the unit and consists of the following components:

• Feed Pump: Delivers the raw material to the system at a controlled rate.

• Heat Transfer Oil Circulating Pump: Ensures a consistent flow of heated oil to maintain optimal process temperatures.

• Heavy Phase Discharge Pump: Extracts the separated heavy phase components and transfer to the next stage distilling cycle (e.g., higher boiling point fractions).

• Light Phase Discharge Pump: Collects the separated light phase components (e.g., lower boiling point fractions).

• Industrial water Circulating Pump: Circulates water to maintain the system’s temperature during operation.

• Pre-Heater: Prepares the feed material by bringing it to the required temperature before it enters the distillation process.

• Molecular Distillation Units: The multi stages distillation columns where separation occurs based on molecular weight and volatility.

• Cold traps : Cools down the vapor to facilitate the condensation of the distilled components.

• Vacuum Buffer Tank: Maintains a stable vacuum environment to prevent sudden fluctuations during the process.

• Vacuum Pump System: Consists of a primary screw or molecular pump and a multi-stages Roots pump, designed to achieve a vacuum level of less than minus 0.1Pa under unloaded conditions.

The distillation system operates at a design temperature range of below 170°C, ensuring that the target components are effectively separated without thermal degradation.

2. Heat Transfer Oil Heating System

The heat transfer oil heating system provides precise temperature control for the distillation unit. The system uses automatic temperature modules to maintain the required process temperature, which is designed to step by step sequentially temperature rise to 180°C. This ensures that the molecular distillation unit operates efficiently, allowing for effective separation of compounds with high boiling points.

3. Chilled Water System

The chilled water system is an essential part of the cooling process within the distillation system. It provides proper temperature water to the condenser to rapidly cool the vaporized fractions, ensuring efficient condensation and separation of light phase components. This system is integrated with the plant’s general utility system.

4. Recirculating Water System

The recirculating water system supplies water for various cooling purposes, including maintaining the temperature of the heat exchangers and other auxiliary equipment. This system also connects to the central utility water system to ensure continuous and reliable cooling throughout the operation.

The multi-stage SPDU system is a robust and reliable solution for processing sensitive materials, especially those with high boiling points or viscosity that require precise temperature and vacuum working conditions. Its advanced design and integration of heating, vacuum, and cooling subsystems ensure efficient separation and maintain product integrity, making it ideal for applications in the chemical, pharmaceutical, and food industries.

Operational Guidelines for SPDU

SPDU system is a highly precise and efficient separation process widely applied in chemical, pharmaceutical, and food industries. To ensure the safety of operators and equipment, strict adherence to operational protocols is essential.

This guideline provides standardized operating instructions and safety precautions to ensure the proper use and running of the short-path molecular distillation system.

1. Environmental Requirements

The molecular distillation system should be operated in a dry, well-ventilated, and dust-free environment. It is recommended to install air conditioning and temperature control systems to maintain consistent ambient temperature and humidity levels.

Operators must wear appropriate protective gear, including protective clothing, safety shoes, and safety helmets, to ensure personal safety during operation.

2. Equipment Operation

Starting up and commissioning of Multi-stage SPDU requires careful planning, preparation, and execution to ensure a successful operation.

Pre-Start Inspection and Preparation for Short Path Molecular Distillation Unit

To ensure optimal performance and maximize output in the industrial production of molecular distillation, it is essential to conduct a thorough pre-start inspection each time the system is restarted after a shutdown. This process helps guarantee the smooth operation of the unit. The following checklist outlines the key inspection steps:

Below are the essential process steps to guarantee a smooth start-up and commissioning:

1. Inspection and Pre-Startup Checks: Before starting the equipment, conduct a thorough inspection to ensure that all components are installed correctly and in good condition. Verify that all connections are secure, and there are no leaks or safety hazards. Perform pre-startup checks according to the manufacturer’s guidelines.
2. System Cleaning and Purging: Clean and purge the distillation system to remove any residual contaminants or impurities. This step is critical to achieving the desired purity of the Omega-3 concentrates.
3. Vacuum System Check: Verify the integrity and efficiency of the vacuum system. Ensure that the vacuum pumps and associated equipment are functioning correctly and capable of reaching the required vacuum levels.
4. Heating System Calibration: Calibrate and test the heating system to ensure accurate and consistent temperature control throughout the distillation process.
5. Cooling System Check: Check the cooling system to confirm that it can maintain the necessary condensation temperatures to collect the distilled fractions effectively.
6. Feedstock Preparation: Prepare the Omega-3-rich feedstock, ensuring it is properly filtered and degassed to remove any volatile impurities that could interfere with the distillation process.
7. Start-Up Sequence: Follow the manufacturer’s recommended start-up sequence for the SPDU functioning. This typically involves gradually increasing the temperature and vacuum levels while introducing the feedstock at the appropriate rate.
8. Process Optimization: During the initial stages of operation, closely monitor the distillation process and make adjustments as needed to optimize the system’s performance. This may include adjusting temperature, pressure, flow rates, and other relevant parameters.

Pre-Start Inspection Checklist

1. Pump Operation Check: Verify that all material pumps are functioning correctly and ensure that the lubricants are adequately filled.
2. Motor and Drive Inspection: Confirm that the motor, reducer, and magnetic drive are operating normally without any unusual noises or vibrations.
3. Glass Inspection: Check the integrity of the glass observation ports to ensure they are intact and free of cracks.
4. Seal Integrity Check: Inspect all sealing devices for any signs of wear or damage, and ensure that all pipelines and valves are clear and functioning properly.
5. Instrument and Electrical Check: Ensure that all instruments and electrical components are in good condition, with wiring connections secured and operational.
6. Condensate Water System: Verify that the cooling water supply is open and properly functioning.
7. Vacuum System Inspection: Check the integrity of the vacuum system to ensure that it is fully operational.
8. Maintenance Follow-Up: Confirm that all necessary maintenance tasks identified during the last shutdown have been completed satisfactorily.

The isolation of EPA (eicosapentaenoic acid) and DHA (docosahexaenoic acid) from fish oil using a short path molecular distillation system involves a series of temperature-controlled stages.

The exact temperature settings can vary based on the specific equipment, feedstock, and desired outcome. However, I can provide you with a general temperature range that you might consider for each stage:

1. Degassing Stage: In this initial stage, you want to remove any volatile compounds. Set the temperature around 50-80°C to evaporate off impurities and volatile substances without significantly affecting EPA and DHA.
2. Preheating Stage: Preheat the fish oil to prepare it for distillation. This stage can be set around 80-90°C.
3. First Distillation Stage: You can start the separation process by targeting lower boiling point compounds. Set the temperature around 90-100°C to begin isolating lighter compounds.
4. Second Distillation Stage: Increase the temperature to around 105-120°C to further isolate the lower boiling points compounds, EPA and DHA, which have higher boiling points compared to the previous stages.
5. Third Distillation Stage: Continue the separation by gradually increasing the temperature to around 120-130°C. This should help focus on the EPA and DHA fractions.
6. Fourth Distillation Stage: Further increase the temperature to around 130-140°C to refine the enrichment of EPA and DHA.
7. Fifth Distillation Stage: As you get closer to the best of the process, set the temperature around 140-150°C to complete the separation and purification of EPA and DHA.
8. Final Stage (Residue): After isolating EPA and DHA, there may be some residue left. Raise the temperature to around 150-160°C to separate and collect any remaining compounds.

Remember, these temperature ranges are general guidelines and can vary based on your specific equipment working conditions, feed composition, and process goals.

It’s crucial to work closely with experienced equipment suppliers that are familiar with the equipment to optimize the distillation process for your fish oil nutrient ingredients manufacturing.

Greatwall Process and Control has been devoted to fish oil refining and concentration equipment business in the past years, We will formulate process solutions and services on the customer’s production process flow and practical demand, and manufacture the optimal facility.

It’s quite significant to choose a supplier that provide excellent customer service and support. We are available to answer your questions and provide technical support throughout the entire process, from installation to maintenance and beyond.

Additionally, safety precautions should always be followed when working with elevated temperatures and volatile compounds. It’s recommended to consult with chemical engineering professionals or experts in the field of short path molecular distillation to fine-tune your process for optimal results.

1. Sampling and Analysis: Regularly collect samples during the start-up and commissioning process to analyze the distilled fractions for desired concentration levels and purity. Adjust process parameters if the desired results are not achieved.
2. Safety Measures and Training: Prioritize safety throughout the start-up process. Ensure that all operators and personnel involved are adequately trained in the operation of the SPDU line and aware of potential hazards.
3. Documentation: Maintain detailed records of the start-up and commissioning process, including operating parameters, adjustments made, and the performance of the equipment. This documentation will be valuable for future reference and troubleshooting.
4. Troubleshooting and Optimization: If any issues or challenges arise during the start-up and commissioning, conduct troubleshooting to identify the root causes and implement necessary corrective actions.

It is crucial to follow the supplier’s guidelines and recommendations during the entire start-up and commissioning process. Additionally, involving experienced personnel or working with experts in short path molecular distillation can significantly contribute to a successful start-up and the smooth operation of the equipment.

Efficient and Reliable Maintenance Procedures for SPDU

To ensure optimal performance and prolonged operational life of SPDU systems, it is essential to implement well-structured and consistent maintenance procedures.

The following guidelines cover best practices to keep the system functioning effectively, and reduce downtime for customers in industries such as petrochemicals, biopharmaceuticals, and food processing.

1. Daily Cleaning

After each use of the distillation system, perform immediate cleaning to avoid residue buildup. Use appropriate solvents like ethanol or ethane to clean the evaporation and condensation surfaces. This will prevent contamination from affecting future distillation processes. Rinse the equipment with deionized or purified water, and wipe the surfaces dry to prevent corrosion or damage.

2. Regular Deep Cleaning

Depending on the frequency of use and the nature of the materials being processed, schedule deep cleaning at regular intervals. Disassemble the system and use suitable cleaning agents to thoroughly clean all parts, including the evaporator, condenser, and piping. For stubborn residues, mechanical cleaning might be necessary. After deep cleaning, rinse thoroughly with deionized water and dry the components with a clean, soft cloth to ensure no moisture remains.

3. Seal and Valve Maintenance

Seals and valves are critical components that ensure vacuum integrity and operational efficiency. Regularly inspect seals for signs of wear or aging and replace them when necessary. Pumps should be lubricated with an appropriate vacuum grease to ensure smooth operation and maintain vacuum tightness. This will prevent leaks and maintain the system’s performance.

4. Vacuum Pump Maintenance

The vacuum pump is the heart of the SPDU system, maintaining the necessary vacuum levels for distillation. Follow the manufacturer’s recommendations for regular oil changes to keep the pump in optimal condition. Monitor the oil levels to ensure clarity and replace oil when it becomes discolored or contaminated. Additionally, regularly check the performance of the vacuum pump and arrange for repairs or replacements as needed to avoid system inefficiencies.

5. Temperature Control System Calibration

Precise temperature control is essential for effective separation in SPDU. Regularly calibrate the temperature sensors to ensure accurate readings. Also, inspect the heating elements and cooling systems to ensure they are functioning correctly. An efficient temperature control system prevents overprocessing and maintains product quality.

6. Electrical System Maintenance

Regularly inspect the electrical connections and wiring of the SPDU system to ensure they are secure and undamaged. Keep the electrical components dry to prevent short circuits and avoid exposure to corrosive gases that could degrade the system’s wiring over time. Back up all system parameters to safeguard operational settings.

7. Software Updates

For systems equipped with software control, ensure that the software is regularly updated to fix known issues and improve system stability. Software updates can introduce new features, enhance process control, and ensure compatibility with the latest technologies. Regularly back up software data to avoid loss of operational information.

8. Operator Training

Regularly train all operators on proper system operation and maintenance procedures. A well-trained team is crucial for maximizing the lifespan of the equipment and minimizing downtime due to operator error. Establish a logbook for tracking equipment usage, operator details, sample information, and maintenance activities. This will aid in future troubleshooting and system analysis.

9. Storage Environment

When not in use, store the molecular distillation system in a dry, clean, and well-ventilated environment. Avoid direct sunlight and humidity, as these can degrade system components over time. The system should be stored away from corrosive gases, flammable substances, and explosive materials to prevent damage or hazardous situations.

10. Safety Inspections

Regular safety inspections should be conducted to ensure the system’s protective features, such as grounding and leakage protection, are functioning correctly. Ensure that all operators are equipped with proper personal protective equipment (PPE) and that safety protocols are strictly followed during system operation and maintenance.

By implementing these maintenance procedures, your process production line can ensure efficient and reliable performance of SPDU systems, leading to longer equipment life, improved safety, and enhanced productivity across various applications. Regular maintenance not only prevents unexpected breakdowns but also maintains the system’s operational integrity, ensuring high-quality outputs in fish oil Omega-3 concentration and other complex separations.

Conclusion:

The sequential SPDU system operates by distilling the heavy phase from each stage of molecular distillation at increasing distillation temperatures.

Due to the complexity of lipid molecules and their interactions, the same compound may show different behavior in a single or binary system than in a multicomponent system. The most important process parameters of the SPDU fractionation are pressure, temperature, feed rate and the rotation speed.

Efficient heat transfer is also significant for the evaporation performance.

SPDU system is highly efficient liquid liquid separation process with proved performance records.