What is the effect of chloride in boiler water?
Chloride and sulfate ions adversely affect the corrosion resistance of most metals and the presence of 100 ppm chloride ions in the water causes pitting corrosion of steel [5] . The chloride ions cause the passive film to break down at certain weak spots on the metal surface and assist corrosion. …
What is chloride test in boiler water?
The chloride test is used (often in conjunction with the conductivity test) to regulate boiler blowdown. Blowdown is necessary to keep boiler solids (both dissolved and precipitated) from building up to the level where they might cause scale and carryover.
What to do if chloride is high in boiler?
Closed main steam stop valve. Increase cut off pressure of boiler. Bypass high pressure cut off of the boiler. Arrange the boiler fire rate to a maximum.
What could high content of chloride impose or effect to the boiler?
Chlorine can contribute to corrosion of boiler tubes. The extent of corrosion depends on the amount of slag formation. Sulfur in the coal tends to reduce the corroding effect of chlorine. Corrosion will be more severe in areas of the boiler with reducing flue gas conditions.
What is P alkalinity in boiler water?
P-ALKALINITY:- THIS TEST IS CARRIED TO FIND OUT THE PRESENCE OF ALKALINE IN BOILER WATER. BOILER WATER SHOULD BE ALKALINE TO SAVE IT FROM CORROSION. ALKALINITY IS DUE TO HYDROXIDE AND CARBONATES AND HYDROXIDE. P ALKALINITY IS USED TO FIND OUT ALKALINITY DUE TO CARBONATES. “P” STANDS FOR PHENOLPHTHALEIN ALKALINITY.
How can we determine the presence of chloride?
The test for chloride ions described here is based on precipitation of an insoluble chloride salt. When a few drops of a silver nitrate solution are added to a slightly acidic aqueous solution that contains chloride ions, a white precipitate of silver chloride will form.
Why do we test pH alkalinity and chloride in boiler feed water?
A PH test indicates how alkaline or acidic your boiler water is. Ideally, the water should be maintained between 9.5-11.5 PH inside the boiler (alkaline environment). Engineers perform this test to prevent acidic corrosion from the water (low PH) as well as scale formation (high PH).
What is the recommended pH of boiler water?
The pH should be maintained between a minimum of 10.5 and a maximum of 11.0 to prevent acidic corrosion of boiler tubes and plates, and to provide for the precipitation of scale forming salts before scale is deposited. Below a pH of 5.0 the water is acidic enough to dissolve the steel boiler plates.
How do you remove chlorides from boiler water?
When it comes to chloride concentration, there isn’t a “chemical treatment” to reduce its levels in the vessel’s boiler water. If the concentration is too high, you will simply need to blowdown and make sure that the replacing water has a lower chloride concentration.
How is high chloride content in boiler water reduced?
Formation of chloride ions can be done by controlling the amount and time of boiler blow down. Standard value of chloride ion is less than 300 mg Cl/l. When calcium phosphates is formed it precipitates on the water surface and can be easily removed by blow down.
Does the presence of chloride leads to boiler corrosion?
The high content of chlorine in biomass will cause serious ash deposition and corrosion problems on the heating surface in boiler, reduce heat transfer efficiency, and endanger the boiler operation safety.
Why is chloride content determination in water necessary?
The measured chloride ions can be used to know salinity of different water sources. For brackish water (or sea water or industrial brine solution), it is an important parameter and indicates the extent of desalting of apparatus required.