Removing Liquid Contaminants in Green Hydrogen Production: Meeting ISO 14687 Purity Standards

Green hydrogen production generates moisture, electrolyte droplets, and fine aerosols that must be removed to protect equipment and meet ISO 14687:2025 Hydrogen Fuel Quality – Production Specification quality purity standards. High‑efficiency coalescers provide reliable liquid/gas separation to support consistent, fuel‑cell‑grade hydrogen quality.

As hydrogen moves through the production process, liquid contaminants can accumulate from compressor oil aerosols to reaction‑generated water and re‑entrained droplets. Without effective removal at each stage, these impurities can damage equipment, shorten dryer life, and prevent the system from achieving the purity levels required for storage, transport, and mobility applications.

Hydrogen producers have long relied on gravity separators, mesh pads, and vane separators. These systems work well for large droplets and steady flow conditions, but they struggle with the fine aerosols common in modern, compact hydrogen plants.

• Gravity separators handle large droplets but require large vessels.
• Mist eliminator pads remove medium‑sized droplets but risk re‑entrainment at higher velocities.
• Vane separators operate at higher flow rates but cannot reliably capture sub‑micron aerosols.

As hydrogen production scales and becomes more modular, these limitations become harder to ignore.

High‑efficiency liquid/gas coalescers address the gaps left by traditional technologies. Using engineered micro‑fibrous media, they capture and merge fine droplets into larger droplets that drain away without re‑entrainment.

Their advantages make them particularly well‑suited for hydrogen production:

• Reliable removal of fine aerosols
• Stable pressure drop across varying flow rates
• Compact vessel design for modular electrolyzer skids
• Essential support for achieving ISO 14687‑compliant hydrogen

Liquid/gas separation is required at multiple stages of hydrogen production:

Compression: Temperature changes cause new water droplets to form, and compressor oil aerosols may enter the gas stream. A coalescer at this stage protects both compressors and downstream catalysts.

Deoxygenation: Removing oxygen generates additional water that must be separated before drying.

Drying (TSA or PSA): Adsorption dryers perform best when the incoming gas is free of aerosols. Even small amounts of oil or electrolyte can shorten desiccant life and increase operating costs.

Throughout the process, separated water and electrolyte can be recycled back to the electrolyzer, improving efficiency and reducing waste.

Hydrogen producers must control a range of contaminants, including moisture, electrolyte carryover, compressor oil aerosols, particulates, hydrocarbons, and oxygen. These impurities are tightly regulated under ISO 14687, which defines the purity requirements for hydrogen used in fuel‑cell applications.

Pall offers a portfolio of high‑efficiency coalescers engineered specifically for hydrogen production, compression, and purification. These solutions deliver high removal efficiency, stable performance, and robust material compatibility across a wide range of operating conditions.

Featured technologies include:

Each product line supports hydrogen producers in achieving ISO 14687 purity levels while protecting critical equipment and reducing total cost of ownership.

As the hydrogen economy grows, purity assurance is becoming a defining factor in production success. High‑efficiency coalescers provide the fine aerosol removal needed to protect equipment, reduce operational costs, and consistently meet ISO 14687 standard. With decades of expertise in gas purification, we deliver the technologies and support hydrogen producers need to supply clean, high‑purity hydrogen for mobility, industrial use, and long‑duration energy storage.

Explore Pall’s hydrogen purification solutions.