Question 390Steam Plants - Assistant Engineer70% to pass
What boiler water chemistry is necessary to ensure the precipitation of hard scale forming calcium?
AI Explanation
The correct answer is C) Boiler water should have a reserve of phosphates.
Phosphates are added to boiler water to control the precipitation of hard scale-forming minerals like calcium carbonate. By maintaining a reserve of phosphates in the boiler water, these minerals are precipitated as soft, sludge-like deposits that can be more easily removed, rather than forming a hard, adherent scale on the boiler surfaces. This helps to maintain efficient heat transfer and prevent damage to the boiler.
The other options are incorrect because: A) Slightly acidic boiler water can actually increase corrosion, B) High water hardness will lead to more scale formation, and D) Hydrazine is used to remove dissolved oxygen, not to control scale.
Related Questions
#388 Normally a boiler water sample should be taken _______________.#389 A sample of boiler water can be chemically tested for alkalinity by initially adding a few drops of phenolphthalein and then slowly titrating the water sample until the _______________.#391 A boiler water sample being collected for analysis should be circulated through a cooling coil because _______________.#392 A boiler with a water capacity of 10 tons generates steam at the rate of 30 tons per hour. If the feed water quality is 0.5 ppm, the concentration of solids will increase 1.5 ppm every hour. What would be the increase in the concentration of solids within 24 hours? #393 Phenolphthalein is used as an indicator to test boiler water for _______________.