What is Chemical Cleaning?
Chemical cleaning uses chemical solutions to remove organic material, oils, grease, mineral deposits, iron and other matter from the interior of systems. Depending on the specific needs of the project, chemical cleaning of pipes or chemical cleaning of a boiler can look a few different ways. It may involve the injection of chemicals into boiler water during firing, use of external flushing equipment and a heat source, or a combination of chemicals with a flow of steam. The chemicals used in the chemical cleaning process vary depending on the type of buildup and the material of the piping system. Acid-based cleaners are commonly used to remove rust and scale buildup, while alkaline cleaners are used for removing grease and oils.
Why is Chemical Cleaning Important?
The chemical cleaning process plays a vital role in maintaining the safety, efficiency and durability of large-scale industrial projects. As time progresses, corrosion, scale and other impurities build up within systems, resulting in reduced performance and costly shutdowns. Chemical cleaning methods help ensure that piping systems stay structurally intact and unobstructed.
Pre-Operational Cleaning vs. Post-Operational Cleaning
Most forms of chemical cleaning fall into one of two categories: pre-operational cleaning and post-operational cleaning. Pre-operational cleaning is performed following construction activities to prepare equipment and facilities for operation by removing any materials that could interfere with performance. Post-operational cleaning may be performed for a variety of reasons, including an observable reduced heat transfer or flow rate following production, increased access for more thorough inspection or to address safety concerns. Some of the most commonly performed chemical cleaning procedures include degreasing only, boiler boil-outs and acid-based chemical cleaning.
What Is Degreasing?
Degreasing removes excess oil, grease, lubricants and other foreign matter from piping, process equipment and steam-generating equipment. Although there are various degreasing methods, the process typically involves an external heat source and temporary circulation pumps.
Which Degreasing Method Should You Use?
The appropriate degreasing method for your project depends on the kind of equipment you’re cleaning and the material it’s made of. Several degreasing techniques include forced circulation and natural circulation like in a boiler boil-out. Degreasing is commonly applied to amine systems, critical oxygen gas systems and some steam-generating equipment.
What Is A Boiler Boil-Out?
Following the manufacturing process, newly installed boilers are often slick with oil, grease and organic material from the boiler’s internal components. If these coatings aren’t removed, they may reduce the boiler’s heat transfer rate and cause tubes to overheat and burst. Due to the risks that contaminants pose to equipment, conducting a boil-out is essential to thoroughly cleanse a boiler.
To decontaminate a boiler, B&W injects a chemical cleaner with a high pH directly into the boiler water to thoroughly degrease and passivate internal surfaces. The heat accelerates the boiler chemical cleaning process as the solution recirculates and dissolves any grease or oil within the boiler’s internal systems. While a boiler boil-out can technically be classified as a degreasing process, degreasing is typically a standalone process using external pumps and equipment. Boiler boil-outs commonly apply to smaller package boilers, HRSG cleaning or other lower-pressure steam-generating equipment. B&W typically performs this on college campuses or other CHP-type projects.
What is Acid-Based Chemical Cleaning?
Acid-based chemical cleaning is commonly applied to high-pressure steam-generating equipment and critical piping systems to remove corrosion, scale and other materials from the interior of systems. It is commonly combined with a degreasing process in a single volume fill to reduce the amount of waste effluent generated during cleaning.
The most common pre-operational chemical cleaning method uses a citric acid-based chemical blend for new equipment to remove mill scale, rust, preservatives and other materials from its surfaces. Once cleaning is complete, an oxidizing agent is used to passivate the metal surfaces to provide protection against further corrosion until the system is put into service. Additional preservation methods, such as introducing nitrogen to the system, may be used if equipment startup is delayed.
FAQs
What are the best methods for chemical cleaning of industrial boilers?
The best chemical cleaning method depends on your boiler type and contamination level.
For new boilers, acid-based chemical cleaning using citric acid effectively removes mill scale, rust and preservatives from high-pressure steam-generating equipment. Boiler boil-outs work well for smaller package boilers and HRSGs, using high-pH chemical cleaners injected directly into boiler water to remove oils and grease. For systems with heavy organic contamination, degreasing with external circulation pumps provides thorough cleaning.
B&W evaluates your specific system conditions, including metallurgy, target contamination and process diagrams, to engineer the most effective chemical cleaning program for your facility.
Can chemical cleaning services help extend the lifespan of boilers?
Yes, professional chemical cleaning significantly extends boiler lifespan by preventing damage caused by scale, corrosion and deposits.
When contaminants accumulate in boilers, they reduce heat transfer efficiency, causing tubes to overheat and potentially fail. Chemical cleaning removes these deposits before they compromise structural integrity.
Regular maintenance cleaning also prevents corrosion that can thin tube walls over time. By keeping internal surfaces clean and applying passivation treatments after cleaning, chemical cleaning services help industrial boilers operate safely and efficiently for decades, protecting your investment and avoiding costly emergency shutdowns.
What safety precautions are necessary during chemical boiler cleaning?
Chemical boiler cleaning requires rigorous safety protocols to protect personnel and facilities. All temporary pipe spools should be fabricated to ASME B31.3 code standards with ANSI B16.5 flanges to eliminate leak risks.
Comprehensive engineering procedures must be developed and followed throughout the cleaning process. The cleaning team should use low-risk chemical solutions and high-quality circulation equipment designed specifically for chemical cleaning applications.
B&W Energy Services maintains one of the highest safety records in the pre-commissioning industry by ensuring that all client, owner and vendor safety specifications are incorporated into engineered procedures. We also provide our teams with extensive training on proper chemical handling, waste disposal protocols and emergency response procedures.
What is boiler chemical cleaning?
Boiler chemical cleaning is a specialized industrial process that uses chemical solutions to remove contaminants from the interior surfaces of boiler systems. The process targets mill scale, rust, mineral deposits, oils, grease and other materials that accumulate during manufacturing or operation.
Chemical cleaning typically involves circulating engineered chemical solutions through the boiler using external pumps and heat sources, or in some cases, injecting chemicals directly into boiler water during firing.
After cleaning, surfaces are passivated with oxidizing agents to prevent corrosion until the system enters service. This critical pre-commissioning step ensures boilers operate at peak efficiency and prevents premature equipment failure.
When should industrial boilers be chemically cleaned?
Industrial boilers should be chemically cleaned during pre-commissioning before initial startup to remove manufacturing residues, mill scale and construction debris. This pre-operational cleaning is essential for all new boiler installations. Post-operational chemical cleaning becomes necessary when you observe reduced heat transfer efficiency, decreased flow rates or increased operating pressures—all signs of deposit buildup.
Many facilities schedule chemical cleaning during planned maintenance outages every 3-5 years, though timing varies based on water quality, operating conditions and boiler type. If you’re planning a boiler inspection and notice visible scale or corrosion, chemical cleaning should be performed before returning the unit to service.
What types of contaminants does chemical cleaning remove from boilers?
Chemical cleaning effectively removes various contaminants that accumulate in boiler systems during manufacturing, construction and operation. Mill scale (iron oxide formed during tube manufacturing) is one of the primary targets, along with rust, corrosion products and metal oxides that reduce heat transfer.
Chemical cleaning also eliminates manufacturing oils, greases and preservatives applied during fabrication and shipping. Mineral deposits, like calcium carbonate, silica scale and other waterside deposits, are removed using specifically formulated chemical solutions. Construction debris, including welding flux, slag, dirt and particulates left during installation, are dissolved or dislodged during the cleaning process. For operational boilers, chemical cleaning addresses hard water scale, process deposits and fouling that accumulate over time.
B&W Energy Services begins every project by analyzing your specific contamination through system evaluation and, when needed, sample analysis to engineer the precise chemical formulation that will effectively remove your contaminants without damaging boiler materials.