Why is alkalinity important in boiler water?
Alkalinity is a key control parameter for boilers (outside of the prescribed operating range, it can lead to corrosion, caustic metal embrittlement, and carryover) and cooling water systems (where it has a significant effect on chemical treatments for scale and corrosion inhibition).
How do I raise the alkalinity in my boiler?
In an emergency, increase the blow down rate if necessary to bring boiler water alkalinity under control. Sodium hydroxide is the preferred approach, as the break down components does not form carbon dioxide. Carbon dioxide will carry off the steam and form carbonic acid in the condensate return lines.
What problems will occur when hard and alkaline water is used in boilers?
Hard water that’s filled with minerals like calcium and magnesium can cause damage to the tubes inside water boilers. If these minerals are present in the boiler’s water supply, it can lead to limescale forming on the surface of the tubes, which has the potential to cause overheating and tube failure.
What is the acceptable P alkalinity of a boiler water?
200-400 ppm
Generally, 200-400 ppm P-alkalinity is maintained in the water for effective control of pH. Inhibitor requirements vary depending on the system. Electric boilers are also used for heating.
How do I test the alkalinity of my boiler?
Alkalinity is measured by titrating a water sample with a standard acid to a designated pH and is recorded as P, M, or T alkalinity. P alkalinity is titrated with phenolphthalein to pH 8.3, M alkalinity with methyl orange indicator to pH 4.6, and T alkalinity with total alkalinity indicator to pH 4.5.
How do you know that the boiler water is alkaline?
The pH value of the boiler water is a number between zero and fourteen. Values below seven are acidic, seven is neutral, and values above seven are alkaline. At a pH between 5 and 9.4 pitting of shell plates will occur at a rate depending on the amount of dissolved oxygen in the boiler.
What is the difference between alkalinity and total alkalinity?
Alkalinity is expressed as phenolphthalein alkalinity or total alkalinity. Phenolphthalein alkalinity measures the hydroxides and half the carbonates at a pH 8.3. Total alkalinity measures all carbonate, bicarbonate, and hydroxide alkalinity at a pH 4.5 (approximately).
How do you test alkalinity?
Alkalinity is usually measured using sulfuric acid with a digital titrator. Sulfuric acid is added to the water sample in measured amounts until the three main forms of alkalinity (bicarbonate, carbonate, and hydroxide) are converted to carbonic acid.
What is alkalinity in boiler water?
Alkalinity in steam-generating boilers is a problem because under heat the alkalinity breaks down to carbon dioxide, which passes with the steam. The alkalinity is principally carbonate (CO3) or bicarbonate (HCO3) anions, which can be expressed in parts per million or as grains per gallon.
How do I reduce the P alkalinity in my boiler water?
You can go directly to a makeup or condensate tank. Dealkalization (salt-splitting process) is an ion exchange system for the reduction of bicarbonate alkalinity of the raw (makeup) water, generally to a steaming boiler. The equipment is very similar to a water softener.
What chemical would be used to control alkalinity in a boiler?
The most common alkaline solutions for boiler water include sodium hydroxide and potassium hydroxide. You can typically purchase these products with a 25 percent concentration or a 50 percent concentration.
Why is alkalinity important in a boiler system?
Alkalinity is a key control parameter for boilers (outside of the prescribed operating range, it can lead to corrosion, caustic metal embrittlement, and carryover) and cooling water systems (where it has a significant effect on chemical treatments for scale and corrosion inhibition). P, M, and T
What should the pH of a steam boiler be?
Carbonic acid is usually neutralized with chemical treatment at each steam directly or indirectly through boiler to produce pH around 8.5 to 9.0. Reduction of alkalinity in the boiler feed water is necessary to minimize the formation of CO 2 and reduce costs of chemical treatment.
Why is it important to control alkalinity in water?
In cooling water, treatment professionals aim to control alkalinity (and pH) to prevent corrosion and scaling. Below acceptable levels, these parameters can contribute to corrosion. The higher the pH, the more alkalinity is present in the carbonate species, which can react with calcium in the water to form scale.
When to test alkalinity in steam and cooling systems?
Both steam boilers and cooling water systems require alkalinity to be tested regularly in order to prevent scale and corrosion, but do you know how to interpret the results?
How does the alkalinity of water affect a boiler?
Generally Boiler feed water pH level is maintained between 9 to 9.5 (Slightly Alkaline) to avoid acidic corrossion. But in case pH is too much Alkaline (Above 10 pH) it causes issues like Caustic embrittlement and
What should the pH of boiler water be?
A typically recommended alkalinity rating is 140 – 700 ppm for boilers operating below 300 psi. Natural water is usually between 6.5 and 7.5 pH. A common recommendation is to maintain boiler water at 8.5 pH.Acidic water is corrosive.
In cooling water, treatment professionals aim to control alkalinity (and pH) to prevent corrosion and scaling. Below acceptable levels, these parameters can contribute to corrosion. The higher the pH, the more alkalinity is present in the carbonate species, which can react with calcium in the water to form scale.
Both steam boilers and cooling water systems require alkalinity to be tested regularly in order to prevent scale and corrosion, but do you know how to interpret the results?
