Application of Vertical Leaf Filters in Crude Oil Filtration

After processes such as pressing, solvent extraction, or preliminary treatment, crude oil typically contains suspended impurities, fine solid particles, and other substances that must be removed. Failure to separate these impurities can interfere with subsequent refining processes, increase equipment load, and compromise the clarity of the finished oil.

Vertical leaf filters employ a closed-system pressure filtration method, utilizing multiple vertically mounted filter leaves to achieve solid-liquid separation; they are well-suited for filtering out fine particles and suspended matter during edible oil processing.

Key Challenges in Crude Oil Filtration

Impurities in crude oil typically consist of fine particles, and the physical state of the material varies depending on the oil source, production process, and pretreatment methods.

Common issues encountered during actual filtration include:

Fine particles tend to pass through the filter medium, compromising the clarity of the filtered oil;
The accumulation of impurities on the filter screen surface leads to a gradual increase in filtration resistance;
Some types of crude oil have high viscosity, necessitating higher filtration pressure and greater filtration surface area;
Open-system operation of filtration equipment can easily result in oil loss or external contamination;

Therefore, crude oil filtration equipment must not only possess sufficient filtration area but also balance filtration precision, sealing integrity, residue discharge efficiency, and ease of cleaning and maintenance.

How a Vertical Leaf Filter Processes Crude Oil

Crude oil is pumped into a sealed filtration tank containing vertically arranged filter leaves.

Under pressure, the crude oil passes from the outside of the filter leaves through the mesh or the pre-formed filter cake layer. Solid particles are trapped on the surface of the filter leaves, while the clarified oil enters the interior of the leaves and is discharged through a collection manifold.

For applications requiring high filtration precision, filter aids such as diatomaceous earth or perlite can be used for pre-coating. The system circulates the liquid with the filter aid to form a uniform filtration layer on the leaf surfaces before proceeding to the actual filtration stage.

Once filtration is complete, air is blown in through the overflow port to remove residual material and dry the filter cake; the vibrator is then activated to discharge the solids. Typically, the vertical leaf filter requires cleaning only once a month.

Advantages of Vertical Leaf Filters for Crude Oil Filtration

Enclosed filtration

The entire filtration process takes place within a sealed tank, minimizing the oil’s exposure to the external environment and reducing the risk of oil loss, leakage, or the ingress of external impurities into the system. This is crucial for maintaining a clean production environment during edible oil processing.

High filtration precision

The mesh on the filter leaves performs initial particle retention; as filtration progresses, the accumulating filter cake layer further contributes to the filtration process. Consequently, this method achieves more consistent filtration results—particularly regarding fine suspended particles in the crude oil—than simple mesh screening alone.

Compatibility with filter aids

Some particles in crude oil are extremely fine, making it difficult to achieve optimal clarity using only metal filter screens. Pre-coating with filter aids—such as diatomaceous earth or perlite—creates a more uniform filtration layer on the filter leaves. This enhances the capture of fine impurities while reducing the risk of fine particles directly clogging the mesh.

Large effective filtration area

Vertical leaf filters accommodate multiple filter leaves within a single enclosed tank, providing a large filtration area within a compact footprint. This increases crude oil processing capacity while minimizing the space required for the equipment.

Automatic vibration-based solids discharge

Upon completion of filtration, the filter cake adheres to the filter leaves. A vibration mechanism dislodges the cake from the leaves, allowing it to be discharged through the bottom outlet; this eliminates the need for manual cleaning of individual filter leaves.

Conclusion

During the processing of crude oil, vertical leaf filters utilize enclosed pressure filtration and large-area filter leaves to separate suspended solids and fine impurities.

For different types of crude oil, the appropriate filtration area and filter screen configuration must be selected based on processing capacity, solids content, viscosity, and filtration precision to achieve more stable filtration performance.

Application of Vertical Leaf Filters in Crude Oil Filtration