Hi guys,
Alain, yes, topping boilers off with water until the injector quits as a shut down procedure is pretty harsh on a boiler- we train our crews to work the water up to about 3/4 glass for the put-away, getting to that level gradually over the last 30 minutes of operation or so. Also- most of that water should go in while there’s still a fire in the belly.
We also train to keep a fire hot until dumped. There used to be a tendency to save coal, and “fire down” on the last trip, to the point where on fire dumping, it was all dead, we were down on pressure, the water wasn’t boiling, and injecting up to that 3/4 glass would be really shocking. Now- last trip is fired no different than the others, and the boiler kept on the ready until the end. The extra coal consumption might amount to a few dollars.
A quick btu loss calc on no 9 shows it to be less than a typical household water heater can handle. The initial thought is to add a zone to the existing bay 4 heating system (oil fired hot water), and use a standard household hot water heat exchanger. A circulator pump and quick disconnects to the blowdown and feed inlets. In the winter the heat loss would be into a room were heating anyway. The system isn’t yet implemented but we’d like to this spring.
Jeff: our ox scavenger is sodium sulfite. This grabs O2 and becomes sodium sulfate. We test effectiveness by measuring residual sodium sulfite.
See ya
Jason