Boiler Water Treatment
Dissolved Oxygen in boilers pose serious threats in steam generating plants by promoting corrosion of the feed water system, the boilers, and the condensate system. Most corrosion problems occur in the hottest areas of the boiler viz., the water wall, screen, and super heater tubes. Other common problem areas include de-aerators, feed water heaters, and economizers. Dissolved gases (primarily O2, CO2), under deposition, attack, lower pH level, attack areas already weakened by mechanical stress, resulting in fatigue and cracking. Many different types of boiler water treatment programs used today around the world to help aid with commercial, industrial and institutional facilities. Primary objectives of a boiler water treatment program are the prevention of both scale formation and corrosion on the internal surfaces in the system. Minimizing corrosion in boiler systems involve removing all traces of oxygen from the boiler feed water and creating conditions, which promote the formation of a passive magnetite film on the internal surfaces. Oxygen scavenger boiler water treatment programs are essential for any company that utilize boilers or steam equipment for their everyday operations.
DEHA or Diethylhyroxylamine is an organic, volatile oxygen scavenger mainly used in high pressure boilers. It is a pale yellow transparent liquid and a derivative of hydroxylamine. It is completely soluble in water alongside its unique combination of properties such as volatility, ability to passivate metal surfaces, and low toxicity makes it the oxygen scavenger of choice for many applications. It has an exceptional property of oxygen scavenging, prevention of corrosion of steel and other metals. It is effective in removing dissolved oxygen thus slowing or eliminating corrosion. It produces a protective film on ferrous-based metals, thus offering enhanced corrosion protection. It is considered a hydrazine replacement and is less toxic.
DEHA has numerous beneficial properties as an oxygen scavenger in boiler feed water systems:
Rapid complete oxygen removal under typical boiler feed water temperature and pH conditions
Promotes passivation of internal surfaces in the boiler system
Volatile in nature and can be easily distilled off boilers
Provides protection to the entire steam condensate system and feed water systems
Reduces corrosion byproduct transport to the boiler minimizing the potential for boiler deposition and corrosion
Improves equipment reliability and efficiency
Minimizes overall condensate system corrosion reducing maintenance costs
Byproducts of DEHA or amines are helpful in raising pH of condensates ergo reducing the consumption of neutralizing amines. The formation of ammonia is very low and hence threat to yellow metallurgy in the system is very minimum when compared to hydrazine based treatment.`