What is the ratio in which Sodium Hexametaphosphate should be added in the boiler water to prevent scaling?
Sodium Hexametaphosphate in Boilers added depending on the feed water quality and blow-down rate that control sludge accumulation. In general pH should be maintained in the rage 9-9-5 and phosphate as ortho-phosphate is 15-30 ppm.
thanku Radwan Al-rasheed. but alklinity such high wont effect the boiler components? moreover will it prevent the scale formation or it will it leave a residue that can be easily removed from the boiler?
As a first guideline, for water with high calcium content you can add 0.5 mg/dm3 of sodium hexametaphosphate, (NaPO3)6, to prevent CaCO3 scaling. To protect from Fe or Mn precipitation, which can occur with O2 or Cl2 dissolved, pH should be above 8.
Cf. Frank N. Kemmer (Ed.), “Agua el disolvente universal”, Spanish translation of: “Water: The Universal solvent” (extracted from “Nalco Water Handbook”), Nalco Chemical Company, P.A.G.S.A., Barcelona, 1978, p. 46.
- Badges
- Science topic
- Similar topics
- Engineering
- Chemical Engineering