Mastering Film-Forming Amines: Boil-Out and Steam Blowing

Abstract  Boil-out and steam blowing are essential pre-commissioning procedures for cleaning and protecting new or refurbished boiler systems. Traditionally carried out with alkaline solutions, these procedures are now increasingly performed with film-forming amines (FFAs) due to their cleaning efficiency, environmental compatibility, and ability to provide immediate corrosion protection. This article outlines best practices for using FFAs during boil-out and steam blowing, explains their advantages over conventional methods, and shares practical insights from real-world applications across different boiler types and pressure levels.

Introduction 

Boil-out and steam blowing serve a critical role in preparing boiler systems for safe and reliable operation. Before first firing, new or refurbished boilers often contain contaminants such as rust, oil, grease, and residues from manufacturing, transport, or installation. Without proper cleaning, these impurities can compromise water-steam chemistry and lead to costly damage, especially to steam turbines.

While traditional alkaline boil-out procedures rely on strong chemicals like sodium phosphate, modern strategies increasingly incorporate film-forming amines. FFAs combine cleaning performance with immediate corrosion protection, enabling safer, more sustainable, and often faster commissioning.

This edition of ODACON Insights explores how FFAs can be used in practical boil-out and steam blowing scenarios.

Why Film-Forming Amines?

When it comes to preparing boilers for safe and stable operation, the advantages of film-forming amines (FFAs) extend far beyond traditional expectations. Historically, pre-commissioning cleanings have relied on strong alkaline solutions—effective but difficult to handle, environmentally taxing, and often chemically aggressive. FFAs, by contrast, offer a fundamentally different approach: one that is both efficient and inherently protective.

Unlike alkaline treatments that depend on high pH values, FFAs perform impressively even in neutral conditions. They’re capable of removing loose iron oxides, residual oils, and manufacturing debris without the need for caustic chemicals or post-treatment neutralization. That alone simplifies handling, lowers risk for plant personnel, and significantly reduces environmental impact.

Yet their true strength lies in what happens simultaneously: while cleaning the system, FFAs also begin building a protective layer on all wetted metal surfaces. This hydrophobic film, formed molecule by molecule, prevents new corrosion from setting in—crucially important during the time between cleaning and full commissioning, when systems are most vulnerable.

Their volatility adds another layer of value. As steam begins to circulate—even partially—FFAs enter the vapor phase and deposit onto internal steam lines. This pre-coating action helps reduce erosion during steam blowing, minimizing the number of blow cycles needed to reach target cleanliness standards. The result? Faster timelines, fewer interruptions, and greater reliability from the first ignition.

Perhaps most importantly, FFAs support a more sustainable approach to plant chemistry. Most formulations are phosphate-free, biodegradable, and non-toxic, making them safe for discharge and easier to incorporate into water treatment strategies. The economic upside is clear as well: reduced chemical usage, lower energy demand, and less water consumption across the board.

Application Guidelines

Laying the Groundwork

Successfully executing a boil-out with film-forming amines begins with careful planning. As with any critical process step, it's essential to understand not just the chemistry but the context in which it's applied.

First, the basics: a reliable water source is essential. Whether from a fully commissioned treatment plant or a temporary supply, the volume and quality must meet the demands of the procedure. Equally important is your heating strategy. If internal burners aren’t yet operational, an external heating setup will be required, along with appropriate storage and supply for the fuel.

Drainage and wastewater handling deserve early attention. Although FFAs significantly reduce the need for neutralization and allow for easier disposal, there may still be site-specific requirements around temperature or discharge limits. Make sure these are addressed in advance to avoid any last-minute bottlenecks.

Analytical equipment also requires forethought. High concentrations of iron and other suspended solids can damage sensitive online monitors, so it's often best to isolate these systems during cleaning and rely instead on manual sampling, turbidity checks, or conductivity measurements.

As for chemical injection, the dosing system must be well-planned and properly integrated. A stable, continuous injection close to the boiler drum or a recirculation loop ensures good distribution. In some cases, piping modifications may be needed to accommodate injection points, pumps, and storage—all of which should be located as conveniently as possible to reduce operator effort and minimize risk.

And finally, if the cleaning is to be followed by steam blowing, the proper bypass arrangement and noise abatement measures must be in place. Many facilities refer to VGB-S-513 as a comprehensive guideline for steam-side cleaning procedures. It outlines flushing, chemical cleaning, and steam blowing standards—and is well worth consulting during the planning phase.

The Procedure in Practice

The FFA-based boil-out begins with a thorough flushing of the boiler using standard tap water. This initial rinse is less about chemistry and more about mechanics: the goal is to physically remove loose particles, welding debris, and any surprises left behind after installation. Once drained, the system is ready for the core procedure.

The boiler is then filled—either with cold water or pre-heated feedwater, depending on site capabilities—and gently brought up to temperature. Many manufacturers provide a staged heating protocol designed to cure refractory linings and minimize thermal stress. These guidelines should be followed closely, ramping up the temperature and holding it steady at each level as prescribed.

Once the system reaches at least 60°C, the FFA dosing can begin. This threshold is critical: injecting below this temperature risks local overdosing and solubility issues. At higher temperatures, the product disperses smoothly and safely. The target concentration typically lies between 1.5 and 2.0 ppm of active ingredient in the boiler water.

If there is no manufacturer guideline for the boil-out, the boiler is then maintained at 150°C for 8 to 12 hours. This extended holding time ensures thorough distribution of the product and allows the protective film to develop evenly across all surfaces. Near the end of this phase, the water level is raised to the system’s maximum—overfilling slightly if possible—to ensure all surfaces are reached. A supplemental dose is usually added at this stage to maintain the target concentration despite dilution.

If steam valves are opened during the procedure, FFAs will naturally migrate into the steam lines, condensing on pipe walls and initiating corrosion protection even before steam blowing begins. This pre-conditioning effect reduces the amount of debris dislodged during steam blowing, which in turn reduces the number of cycles needed.

When the hold period concludes, the system is drained—ideally while still hot—to remove residual impurities. Water samples are then checked for turbidity, ion content, or total organic carbon (TOC). In most cases, one repeat cycle is sufficient to achieve the desired cleanliness. In particularly contaminated systems, a third may be required, though such cases are rare in practice.

Case Studies

Low-Pressure Hospital Boilers – New Zealand

Three low-pressure boilers (23 m³/h steam) underwent FFA boil-out before service. Despite differing manufacturers and boiler conditions, all units achieved clean, hydrophobic surfaces after two cycles. Initial black and turbid water turned clear, with visible reductions in sludge and corrosion products.

Biomass CHP – New Zealand

A 30 MW biomass boiler experienced rapid drops in iron and turbidity following FFA dosing. The protective film formed consistently, as evidenced by improved visual clarity and stabilized conductivity and pH throughout the procedure.

Sugar Mill Power Plant – Switzerland

A 50-bar drum-type boiler was treated during the refractory dry-out process. With no injection ports available, FFAs were added directly via modified drum access. Despite this improvisation, the boil-out achieved excellent results: clean internal surfaces and effective conditioning without phosphates or dispersants.

Conclusion

Film-forming amines offer a powerful, efficient, and environmentally responsible alternative to conventional alkaline boil-out and steam blowing procedures. Their ability to clean and protect in a single step simplifies commissioning, shortens timelines, and supports long-term asset reliability.

From low-pressure auxiliary boilers to high-pressure industrial units, FFA-based pre-cleaning is proving itself as a modern standard, especially where safety, flexibility, and sustainability are top priorities.

Author

Bio Ronny Wagner is the Managing Director at REICON Wärmetechnik und Wasserchemie Leipzig GmbH. As an experienced water treatment professional, he specializes in the application of film-forming amines in water-steam cycles, as well as in closed cooling and heating systems. With over 15 years of experience in the preservation of nuclear, fossil, and industrial power plants, he has played a pivotal role in advancing industry best practices. As an active member of vgbe and the IAPWS Power Cycle Chemistry (PCC) group, he has co-authored several international standards for the safe and effective application of film-forming amines in power plant chemistry.