Page 152 - Boiler plant and distribution system optimization manual

Over 100 Ways to Improve Efficiency 137

3. Oxygen sensors and feel for unusual vibrations and noises. You
4. Repair a leaking seals on combustion air pre- might be surprised at what can be found even
heaters disconnected linkages and burners not securely
5. Install turbulators bolted to the furnace.
6. Chemically clean internal boiler scale to im-
prove heat transfer
7. Clean fire-side deposits to improve heat 2. CONDUCT INFRARED SCANS
transfer OF BOILER AND STEAM LINES.
8. Check for hot gas short circuits indicating
defective baffles There are some good instruments available
for conducting infrared scans of boiler and steam
lines to identify poor refractory and insulation.
1. REPLACE BINDING OR WORN
They can identify hot spots and energy losses
CONTROL SYSTEM LINKAGES.
quickly and easily identify unusual energy loss-
Boilers seem to operate for years on a 24/7 es. Figure 10.32 shows the graphic results of such
basis with no problems while all this time parts a scan.
are wearing and vibrating with continuous use.
Nothing seems to go wrong. Boilers are not like
engines that begin to vibrate and make strange 3. ExCESS AIR INDICATORS
noises when they begin to have problems. It’s a
good idea to check the control linkages for open- Oxygen sensors provide information for ex-
ing clearances and play, just a little bit of play can cess air indications on a continuous basis which
start costing money. A good check is to test for can be quite helpful for tracking boiler efficien-
flue gas oxygen levels at selected load points, this cy trends. This is a prime indicator of operating
and a hand over hand examination of parts will efficiency and also as a trouble indicator for the
tell the story. Cycle the controls with the boiler off burner and combustion control systems.

Figure 10.32—Shows a sample
of a graphic scan of a boiler
surface which has been dis-
played on a spreadsheet grid
for easy summation of results.
This scan was done with an in-
frared instrument that directly
measured Btus radiated from
the boiler surface in Btus per
square ft per hour; a handy
number to use in a grid like
this. Using this and surface
temperature information, trou-
ble spots can easily be identi-
fied.