Characteristics of boiler feedwater - Lenntech
At sea level atmospheric pressure, water boils at about 212oF. With increasing pressure, the boiling point also increases. At a pressure of 200 psig, for example, water boils at a temperature of about 388oF. At the critical pressure of 3200 psig (where water is converted to steam without change in volume), the boiling point is 704oF.
When generating steam at supercritical pressure, for. example, 4500 psi. (pounds per square inch), the maximum iron content in the feed water should not exceed .010 ppm. (parts per million) to
If boiler water gets too high in total dissolved solids, then it becomes inefficient and expensive to operate. Sulphite Elevated iron levels can indicate corrosion within the boiler, so iron becomes an important parameter to monitor. Condensate Good condensate is the best quality, least expensive water most systems can
The consensus is that feedwater oxygen, iron, and copper content should be very low (e.g., less than 7 ppb oxygen, 20 ppb iron, and 15 ppb copper for a 900 psig boiler) and that pH should be maintained between 8.5 and 9.5 for system corrosion protection.
Boiler Feedwater Treatment (Part I): Why Water Treatment is Necessar
Characteristics of boiler feed water Water absorbs more heat for a given temperature rise than any other common inorganic substance. It expands 1600 times as it evaporates to form steam at atmospheric pressure. The steam is capable of carrying large quantities of heat.
Objectives of Internal Water Treatment. 1 To control the level of total dissolved solids (TDS) within the boiler As water is boiled within the boiler and steam is produced, then the solids remain in the water and concentrate. Thus, over time the level of total dissolved solids (TDS) increases. Further evaporation causes these dissolved solids to come out of solution, and to produce suspended solids (sludge).