The treatment of boiler water can be put into two parts. These are internal treatment and external treatment. (Sendelbach, p. 131) The internal treatment is for boiler feed water and external treatment is for make-up feed water and the condensate part of the system.
Why feed water treatment is necessary in a boiler?
Feedwater must be pretreated to remove impurities to control deposition, carryover, and corrosion in the boiler system. Poor quality water gives poor quality steam. The first step in any treatment is filtration of suspended solids.
What is the significance of feed water treatment in power plant?
Feedwater treatment is a pre-water treatment process to control deposition, eradicate impurities and prevent corrosion within a boiler system. In a boiler system, water is transformed into steam and expands by as much as 1000 times as it passes through steam pipes at rates of 100km/hr.
What is the pH of boiler feed water?
Boiler water should be maintained at pH 11. Generally, the higher the pH (basic), the less soluble some solids are in the water. The lower the pH (acidic), the more soluble these solids are.
How do you remove oxygen from boiler feed water?
Heating the feed water and maintaining it at a high temperature prior to its delivery to boiler, in the feed tank can drive off both oxygen & free carbon dioxide. Any remaining oxygen can then be dealt with by the addition of a chemical oxygen scavenger such as catalyzed sodium sulphite.
What are the 5 control of boiler carryover?
As discussed earlier, the principle chemical factors causing carryover are the dissolved solids, suspended solids, alkalinity, silica (vaporous carryover), and oil contents of boiler water. In many cases, limiting the concentration of these components will satisfactorily control carryover.
Why boiler feed water pH is high?
It comes into play with steam boilers because a pH between 7 and 9 (slightly alkaline) is just right. If the pH is lower than that, the water will start eating the pipes. If it’s higher than that, the water won’t corrode metal, but it may begin to foam, and that’s not good. Hold that thought for a moment.
Which chemical is used to remove co2 from Boiler feed water?
Deaerators are commonly used to remove dissolved gases in feedwater for steam-generating boilers.
Why is de aeration important?
The purpose of a deaerator is to reduce dissolved gases, particularly oxygen, to a low level and improve a plant’s thermal efficiency by raising the water temperature. In addition, deaerators provide feedwater storage and proper suction conditions for boiler feedwater pumps.
