The manufacturing and process industries throughout the world require steam boilers for processing operations. Steam boilers are undoubtedly irreplaceable equipment in the industries for heating, drying, and sterilization purposes. Plant managers ensure that the boiler systems are functioning smoothly and delivering optimum productivity. Regular maintenance and following standard guidelines are important to ensure the safety of the process plant and hassle-free operations. However, some boiler problems are inevitable and require prompt action to avoid significant losses or harm. Among many issues occurring in steam boilers, priming and foaming are the two most commonly found boiler problems. Let us understand both concepts in detail.
Priming:
As the steam boiler generates steam rapidly, some water particles are carried along with the steam. The process of formation of wet steam is known as priming. Due to the carryover of water droplets in the steam, the energy efficiency of the steam is reduced. It leads to salt crystals deposition on the superheaters and turbines. Improper construction of steam boilers, sudden fluctuation in steam demand, and excessive ratings are some of the primary causes of priming.
Minute drops entrainment is unavoidable in steam boilers. If the boiler water carryover is excessive, it results in steam-carried solids producing turbine blade deposits. The composition of the deposits is similar to the dissolved solids in the boiler water. Since priming is a major cause of the high level of boiler water carryover, it consequently leads to the failure of superheaters. Priming takes place due to the viscosity of water and its possibility of foaming. These properties depend on the alkalinity, presence of organic substances, and total dissolved solids or TDS. The level of priming is related to the design of the steam boiler and the steaming rate.
Priming leads to the deposit formation in the valves that causes overheating and corrosion in superheaters. It affects the heat transfer that results in low quality of processed product, higher level of steam consumption, and lowers the overall lifecycle of the steam boiler system.
Causes of Priming:
Effects of Priming:
Prevention for priming:
Ensuring chemical presence in the boiler water does not exceed the required amount
Foaming:
Foaming is the unrelenting formation of bubbles or foam in the steam boiler that does not cease easily. It is caused due to the oily substances in water that reduce the surface tension in the boiler water. The contamination of the steam with solids in boiler water causes water carryover. The froth or bubbles formed at the surface of the boiler passes out with the steam. The phenomenon, known as foaming, is caused by a high concentration of solids present in the boiler water. It has been found that particular substances such as alkalis, fats, oils, grease, and specific types of organic matter are specifically instrumental in foaming.
In addition, the suspended solids accumulated in the surface film that surrounds the steam bubble result in a persistent deposition. It leads to resistance in the bursting of a steam bubble that builds up foam. It has been observed that finer suspended particles accumulate on a higher level in the bubble.
Causes of Foaming:
Effects of Foaming:
Prevention of Foaming:
Introducing anti-foaming agents such as castor oil, tannic acid, gallic acid, etc.
Administrating compounds like sodium aluminate for eliminating oil from the boiler water
Since 1983, Rakhoh Boilers has emerged as a trusted boiler manufacturer in Pune, delivering efficient and reliable industrial steam boilers in over 26 countries globally. We manufacture superior quality products like steam boilers, waste heat recovery boilers, thermic fluid heaters, and boiler accessories. We are renowned for our excellent after-sales services like energy audit, boiler automation, steam trap assessment, annual boiler maintenance, etc., to ensure the hassle-free efficiency and productivity of the steam boilers.
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