Steam boiler scale at a Washington chemical plant
Steam boiler scale was building in two diesel-fired boilers, of 600 and 700 HP, at a chemical plant in Wapato, Washington. The well water ran at about 200 ppm hardness and a softener brought it to about 80 ppm, yet heavy scale persisted. Acid cleaning meant about a week offline and more than $15,000, and replacing either boiler could cost about $350,000. Three HydroFLOW® i60 units were fitted: one on the softened make-up line to the deaerator tank and one on the feed to each boiler. Scale began leaving through blowdown within days, and within 2.5 months daily diesel use fell from 400 to 275 gallons.
The Challenge
- Steam boiler scale persisted in both diesel boilers despite water softening
- Make-up water was still about 80 ppm hardness after the softener
- Acid cleaning required about a week offline and cost more than $15,000
- Replacing either boiler could cost about $350,000
The Solution
- Units installed: three HydroFLOW® i60
- Installation points: the softened make-up line to the deaerator tank, and the feed line to each boiler
- Boilers: 600 HP and 700 HP low-pressure diesel steam boilers
- Water: well water at about 200 ppm, softened to about 80 ppm
To tackle steam boiler scale without another acid clean, one unit treated the softened make-up water going to the deaerator tank, and each boiler had its own unit on its feed line. Within days, soft grey and red putty-like scale was coming out through the boiler blowdown, and stack temperature and fuel use were tracked over the following 2.5 months.
