Divyam Mandalia, Director of Global Purification at PSB Industries, discusses the role of advanced oxygen removal in chlor-alkali processing.
Chlor-alkali production is among the most energy intensive processes in the chemical industry. Through electrolysis, sodium chloride is converted into chlorine and caustic soda, with hydrogen generated as a byproduct. Historically, that hydrogen stream was often treated as secondary, used internally where possible or vented when purification requirements made recovery impractical.
That mindset has shifted. Producing hydrogen, especially at usable purity levels, has become increasingly expensive, regardless of whether the end use is fuel, feedstock, or resale.
Venting hydrogen is no longer viewed as a neutral operational choice; it represents lost value. As a result, chlor-alkali operators are reassessing how effectively they capture, clean, and reuse hydrogen generated within their own processes.
This shift has elevated gas purification from a downstream afterthought to a core efficiency lever. The challenge is not simply capturing hydrogen but refining it to meet downstream requirements without introducing new inefficiencies or hidden losses elsewhere in the system.
Why hydrogen purity, and how it’s achieved, matters more than ever
Hydrogen produced from electrolysis processes is not clean by default. Oxygen and moisture are intrinsic byproducts of the process, and trace contaminants such as carbon dioxide, carbon monoxide, and halogenated species are often present as well.
While concentrations may be low, their impact downstream is significant. Many chlor-alkali facilities route hydrogen through pressure swing adsorption systems or other polishing steps to meet final purity specifications.
These systems are sensitive to oxygen content. Higher oxygen levels reduce hydrogen recovery, increase purge losses, and place greater stress on adsorption media. In practical terms, facilities may sacrifice a meaningful percentage of usable hydrogen simply to remove oxygen later in the process.
Several purification technologies are commonly applied upstream, including membranes and PSA-based approaches. While effective for bulk separation, these technologies struggle when tasked with removing oxygen to very low outlet concentrations.
Their efficiency declines sharply at the trace level, where removal must occur at parts-per-million thresholds rather than percentage points.
Catalytic oxygen removal, often referred to as Deoxo purification, addresses this limitation directly. Instead of separating oxygen from hydrogen, catalytic systems convert oxygen into water through controlled oxidation.
This approach enables near complete oxygen removal, often down to one part per million by volume or lower, without relying on adsorption capacity or purge-intensive operation.
Because the reaction itself generates water, high performance drying becomes a necessary companion technology. Advanced dryer systems remove the resulting moisture to similarly low levels, ensuring the hydrogen stream meets downstream requirements without shifting the burden of impurity removal further along the process.
Together, catalytic oxygen removal and deep drying form a purification strategy optimized for trace-level control rather than bulk correction.
Regeneration strategy, hydrogen recovery, and downstream performance
Dryer systems operate cyclically. As desiccant beds become saturated, they must be regenerated by desorbing moisture from the media. That regeneration step typically relies on a slipstream of process gas, which is heated and routed through the saturated bed. In many systems, regeneration occurs at reduced pressure.
While technically effective, depressurization introduces gas losses that are easy to overlook, particularly when hydrogen is viewed as a secondary stream. Over time, however, these losses accumulate. Each regeneration cycle represents hydrogen that is vented rather than recovered, quietly eroding overall process efficiency.
Operating regeneration at full system pressure eliminates this inefficiency. By maintaining pressure during regeneration, hydrogen remains within the process instead of being lost through venting. Although high pressure regeneration can increase capital cost, its lifecycle impact is often decisive. When evaluated over five or ten years of operation, avoided hydrogen losses frequently outweigh the initial investment.
The benefits of advanced oxygen removal extend beyond the dryer itself. By reducing oxygen levels upstream, facilities can dramatically improve the performance of downstream PSA systems. Lower oxygen concentrations lead to higher hydrogen recovery, reduced purge requirements, and longer adsorption media life.
Equipment operates under more stable conditions, maintenance intervals extend, and total cost of ownership declines. In some applications, the addition of dedicated oxygen removal has paid for itself in less than a year through improved hydrogen recovery alone. In this context, purification is no longer a cost center, it becomes a recovery strategy that protects the value of hydrogen already produced.
Integration without disruption
One barrier to adopting advanced purification technologies is concern over integration. Chlor-alkali facilities often operate with tightly controlled automation standards, and introducing new equipment must not disrupt existing control architectures. Modern purification systems should be designed with this reality in mind. Controls can be aligned with plant standards, whether Allen-Bradley, Siemens, or other platforms, ensuring seamless communication with upstream and downstream equipment. This flexibility allows purification systems to be added or upgraded without forcing broader control system changes.
The ability to adapt to evolving project requirements is equally important. In facilities where specifications may run hundreds of pages, or where design changes emerge mid-project, close coordination between engineering, fabrication, and commissioning becomes a practical necessity rather than a nice to have.
These efficiency driven approaches are increasingly visible in how companies like us support hydrogen purification in chlor-alkali applications. By combining catalytic oxygen removal with high performance drying and zero-gas-loss regeneration, we focus on maximising hydrogen recovery while minimising operational waste.
For operators balancing legacy infrastructure with evolving performance expectations, that flexibility can be as valuable as the purification technology itself.
Turning purification into a strategic advantage
As hydrogen continues to gain importance across chemical processing and energy markets, chlor-alkali producers are uniquely positioned. They already generate hydrogen at scale; the challenge lies in capturing its full value.
Advanced oxygen removal and drying technologies offer a clear path forward, one that prioritises recovery, reliability, and long-term efficiency over short term convenience. When purification is designed not merely to meet specifications but to protect hydrogen recovery across the system, it becomes a strategic advantage rather than a necessary expense.
Just as important as the technology itself is how purification systems are engineered, built, and supported. Facilities increasingly benefit from partners that can move quickly between design and fabrication, adapt to evolving project requirements, and align closely with existing plant standards.
Shorter feedback loops between engineering and manufacturing allow systems to be customised without introducing delays, while vertical integration helps ensure that design intent carries cleanly through fabrication, testing, and commissioning.
This approach becomes especially valuable in complex or fast-moving projects, where specifications may evolve, tie-in constraints emerge late, or integration details need to be refined in real time.
Purification solutions that are developed, fabricated, and supported under one roof are often better equipped to respond to these realities, reducing turnaround time, minimising rework, and simplifying coordination for plant teams.
For chlor-alkali operations reassessing how they manage hydrogen streams, the opportunity is straightforward but consequential: cleaner gas, higher recovery, faster project execution, and a stronger return on energy already invested.
In that context, purification is no longer just a unit operation, it becomes an enabling component of a more resilient, efficient production strategy.
