Chemical cleaning of CuNi Tubes?
Chemical cleaning of CuNi Tubes?
(OP)
Is there any easy way to chemically clean the CuNi tubes of a heat exchanger that are coated with calcium carbonate, etc. after water heater service?
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RE: Chemical cleaning of CuNi Tubes?
Calcium scales such as calcium sulfate, calcium carbonate and calcium oxalate are insoluble in water. However, all three are soluble in a Sodium Bisulfate acid solution. Calcium scale can be removed with an acid wash using a 5-15% solution of Sodium Bisulfate (SBS). SBS can also be used during a shut down to remove scale by re-circulating it throughout areas of the process where needed. The concentration of SBS solutions and the re-circulation time depend on the amount of scale that needs to be removed. The following chart shows (by weight) the theoretical amount of SBS required to remove one pound of calcium scale.
0.95 lb. Pounds SBS To Remove 1lb. Calcium sulfate
2.5 lbs. Pounds SBS To Remove 1lb. Calcium carbonate
3.2 lbs. Pounds SBS To Remove 1lb. Calcium oxalate