Re: NNG...More water woes for Alamosa!

Various compounds are used to chemically bind the ions that can cause boiler scale. One pair of compounds often used are Sodium diphosphate and sodium triphosphate. The idea is that the phosphate ion will preferentially bind to ions that exist in the boiler water so that they will form a sludge that can be blown down instead of binding to a Calcium (or worse, a sulfur) ion and form a scale which plates out on the inside of the boiler shell and inhibits heat transfer. This boiler scale then has to be manually removed from the inside of the shell which is a tedious and time-consuming process (ask me how I know this...). Two chemicals are used since they act as a "buffer" (any chemists out there?) so that a "positive inventory" is maintained in the boiler water without continuous attention by the crew who has more important things to do.

Bill Daniels
Santa Rosa, California