Page 233 - Boiler_Operators_Handbook,_Second_Edition

218 Boiler Operator’s Handbook

you looking unprepared and could generate significant ers are operated with only the forced draft fan running
unnecessary costs. The wise operator will always have you are creating an explosive mixture of dust and air
contingency plans for failure of each piece of equipment with enough energy added by the steam to create a
and service. static spark. I’ve noticed a lot of new designs with soot
Service? Yes, you need to have a plan for the blowers connected to a header instead of the respective
failure of every utility. Loss of electric power is a com- boiler, that’s wrong!
mon occurrence and I’m always amazed at how some Of course soot blowers have to be intact and in-
customers respond to it. They are always in a quandary stalled right to do a good cleaning job. You should be able
when the generator fails to start or shuts down shortly to tell by the sound if they’re working right. If the end of
after the electricity is lost. You need plans that include the soot blower has corroded or burnt off or the element is
procedures in the event standby equipment fails, loss misaligned so the steam jets are hitting the tubes (a good
of the utility becomes long term, or conditions prevent way to cut through the tubes) you should be able to tell
delivery. by the sound. When soot blowing doesn’t do the job and
When replacing small parts and items make a fuel additives don’t do the job then the boiler has to be
concerted effort to ensure you’re replacing something of cleaned with a high pressure water wash.
equal quality. A big problem with valves
is they cost less when furnished with
reduced trim (a smaller opening). Mo-
tors with a service factor may be using
it and a larger motor may be required.
Modern technology has also provided
better and lower cost alternatives, espe-
cially motors and controls, that should
be considered when replacing parts and
equipment.

Boiler Tube Cleaning—Replacement
One thing that is designed to be
replaced is a boiler tube. They’re de-
signed to transfer heat rapidly so they
are more likely to be coated with scale.
They’re thin, also for heat transfer, so
they will corrode through first. There
are means for cleaning scaled tubes so
they don’t have to be replaced but water
side cleaning occasionally penetrates
Figure 6-9A. Firetube cleaner
the tube so replacement is necessary.
Fire side cleaning can be performed by wire brush-
ing the tubes of fire tube boilers. A modern piece of
equipment (Figure 6-9A) that connects to a vacuum
to collect the removed soot and a motor driven brush
makes the job relatively easy and a lot cleaner than
using a brush on a pole like I used to (Figure 6-9B).
Without the machinery your spouse won’t let you into
the house until you’ve stripped and put all your sooty
clothes in a bag.
Fire side cleaning of water tube boilers is normally
accomplished with the boiler in operation using soot
blowers. Note that soot blowers should be used only
when the boiler is firing. During boiler operation the
flue gas inside is essentially an inert gas. If soot blow- Figure 6-9B.