You have the ability to determine the total amount of dissolved solids in your plant's boiler water by measuring conductivity.
Conductivity is the measure of a solution's ability to conduct electricity. Electrical current is carried by dissolved solids present in the water.
Therefore, current is negligible in pure water. But current is measurable in water which contains dissolved solids.
Measuring conductivity gives no indication of what is in the water, but it will give you a good indication of the total amount of dissolved solids present.
Total dissolved solids may be controlled by the continuous blowdown, which typically is removed from the steam drum, or by manual blowdown. Guidelines for maximum TDS levels in boilers operating at various steam pressures are shown in tables.
It is advisable to keep the TDS in the boiler water just below the maximum allowed in order to save fuel, water and treatment chemicals.
Because of the time it takes to determine the TDS by evaporation, the TDS is calculated from the water's conductivity.
The relationship between TDS and conductivity varies depending on the water quality.
For boilers that use synthetic polymers as a sludge dispersant, a factor of 0.7 times the neutralized conductivity (in µmhos) may be used.
For boilers that use Quebracho tannin, the factor will vary from 0.7 to 1.0 depending on the amount of tannin in the water.