Substituting in Equation 11:
15,000 pph = 534 pph
2,500 - 86
Function. All steam generating systems, where steam is evaporated
leaving cumulative solids from the feedwater in the boiler, should be treated
with chemicals internally while the system is in operation. Internal
treatment is also used to eliminate oxygen not removed by the deaerator.
Table 17 gives the limiting boiler water concentrations.
Blowdown. Intermittent and continuous blowdown ensure that these
limits are not exceeded. Raw water treatment limits the amounts of dissolved
Chemicals Used. The actual internal chemical treatment, aside from
the method of feeding and controlling the treatment, is part of the plant
operation. A list of chemicals for internal treatment is given in Table 20 to
assist in selection of the feeding method.
Chemical Feeding Equipment
Mixing or Dissolving Tank. For small installations, the mixing
tank may consist of a steel barrel with proper piping connections, or it may
be combined, as shown in (a) of Figure 26. A more elaborate dissolving tank
for larger plants is shown in (b) of Figure 26.