Introduction
In the field of liquid-liquid separation, coalescer is used to separate emulsions into their components using coalescence of droplet. the Coalescence Filter Element and Separation Filter Element work hand in hand as an ideal combination, delivering efficient and precise separation in industries such as petrochemical, chemical, and environmental protection. Through complementary functions, they ensure high separation efficiency and long-term reliability.
Core Functions: A Balanced Synergy
1. Coalescence Filter Element – The “Pre-Treatment Expert”
Working Principle:
Using mechanisms like inertial impaction, diffusion interception, and direct interception, this filter captures small droplets on the fiber surface. Through surface tension, these micro-droplets gradually merge into larger ones, which then fall off under gravity.
Core Function:
The Coalescence Filter Element provides both filtration and coalescence. It first removes solid contaminants (filtration accuracy up to 0.1–25 μm), then uses hydrophilic properties to break emulsions and merge dispersed water droplets, converting micron-sized droplets into millimeter-sized drops for easier removal.
2. Separation Filter Element – The “Final Purifier”
Working Principle:
Made from oleophobic and hydrophobic synthetic fibers or specially treated materials, its ultra-low surface energy prevents unwanted liquids from adhering to the surface. This enables selective filtration, allowing “oil through, water blocked” or “water through, oil blocked.”
Core Function:
Serving as the final stage of separation, it blocks enlarged droplets (e.g., water beads) on the outer surface while allowing the target liquid (e.g., oil) to pass through. This ensures deep dehydration or de-oiling, achieving high purity in the output.
How They Work Together: From Coalescence to Separation
1. Pre-Treatment Stage (Coalescence Filter Element)
The mixed liquid (such as oil-water) first passes through the coalescence filter. Solid impurities are trapped, and tiny droplets merge into larger ones (e.g., water droplets from <10 μm to >50 μm), some separating naturally under gravity.
2. Deep Separation Stage (Separation Filter Element)
The fluid then flows through the separation filter. Due to its hydrophobic and oleophilic properties, residual microdroplets are blocked, allowing clean liquid to exit. Collected droplets form and are drained from the system.
3. Performance Synergy
The Coalescence Filter Element solves the problem of tiny droplets being difficult to separate, while the Separation Filter Element ensures complete removal of remaining droplets. Together, they increase overall separation efficiency from 80–90% up to over 99.9%.
Typical Applications
1. Petrochemical Industry
Used in fuel dehydration systems, where the coalescence filter removes impurities and merges water droplets, and the separation filter provides fine dehydration. Ensures clean fuels such as aviation kerosene and diesel, preventing corrosion and improving engine reliability.
2. Environmental Protection
In oil-contaminated wastewater treatment, the coalescence filter merges emulsified oil into larger droplets, while the separation filter intercepts the oil phase, allowing treated water to meet discharge standards (<10 ppm oil content).
3. Pharmaceutical & Food Processing
Used for separating immiscible liquids (e.g., solvents and water). The coalescence filter removes fine impurities and enhances phase separation, while the separation filter ensures ultra-pure, residue-free liquids that meet high hygiene standards.
